ovs-vswitchd.conf.db(5)       Open vSwitch Manual      ovs-vswitchd.conf.db(5)



NAME
       ovs-vswitchd.conf.db - Open_vSwitch database schema

       A  database  with  this  schema  holds  the  configuration for one Open
       vSwitch daemon. The top-level  configuration  for  the  daemon  is  the
       Open_vSwitch  table,  which  must  have  exactly one record. Records in
       other tables are significant only when they can be reached directly  or
       indirectly  from the Open_vSwitch table. Records that are not reachable
       from the Open_vSwitch table are automatically deleted  from  the  data‐
       base, except for records in a few distinguished ``root set’’ tables.

   Common Columns
       Most  tables contain two special columns, named other_config and exter
       nal_ids. These columns have the same form and purpose each  place  that
       they appear, so we describe them here to save space later.

              other_config: map of string-string pairs
                     Key-value  pairs  for  configuring  rarely used features.
                     Supported keys, along with the forms taken by their  val‐
                     ues, are documented individually for each table.

                     A  few tables do not have other_config columns because no
                     key-value pairs have yet been defined for them.

              external_ids: map of string-string pairs
                     Key-value pairs for use by external frameworks that inte‐
                     grate  with Open vSwitch, rather than by Open vSwitch it‐
                     self. System  integrators  should  either  use  the  Open
                     vSwitch  development mailing list to coordinate on common
                     key-value definitions,  or  choose  key  names  that  are
                     likely to be unique. In some cases, where key-value pairs
                     have been defined that are likely to  be  widely  useful,
                     they are documented individually for each table.

TABLE SUMMARY
       The  following list summarizes the purpose of each of the tables in the
       Open_vSwitch database.  Each table is described in  more  detail  on  a
       later page.

       Table     Purpose
       Open_vSwitch
                 Open vSwitch configuration.
       Bridge    Bridge configuration.
       Port      Port configuration.
       Interface One physical network device in a Port.
       Flow_Table
                 OpenFlow table configuration
       QoS       Quality of Service configuration
       Queue     QoS output queue.
       Mirror    Port mirroring.
       Controller
                 OpenFlow controller configuration.
       Manager   OVSDB management connection.
       NetFlow   NetFlow configuration.
       SSL       SSL configuration.
       sFlow     sFlow configuration.
       IPFIX     IPFIX configuration.
       Flow_Sample_Collector_Set
                 Flow_Sample_Collector_Set configuration.
       AutoAttach
                 AutoAttach configuration.

Open_vSwitch TABLE
       Configuration  for  an  Open  vSwitch daemon. There must be exactly one
       record in the Open_vSwitch table.

   Summary:
       Configuration:
         bridges                     set of Bridges
         ssl                         optional SSL
         external_ids : system-id    optional string
         external_ids : xs-system-uuid
                                     optional string
         external_ids : hostname     optional string
         external_ids : rundir       optional string
         other_config : stats-update-interval
                                     optional string, containing  an  integer,
                                     at least 5,000
         other_config : flow-restore-wait
                                     optional string, either true or false
         other_config : flow-limit   optional  string,  containing an integer,
                                     at least 0
         other_config : max-idle     optional string, containing  an  integer,
                                     at least 500
         other_config : hw-offload   optional string, either true or false
         other_config : tc-policy    optional string, one of none, skip_hw, or
                                     skip_sw
         other_config : dpdk-init    optional string, one of false,  true,  or
                                     try
         other_config : dpdk-lcore-mask
                                     optional  string,  containing an integer,
                                     at least 1
         other_config : pmd-cpu-mask
                                     optional string
         other_config : dpdk-alloc-mem
                                     optional string, containing  an  integer,
                                     at least 0
         other_config : dpdk-socket-mem
                                     optional string
         other_config : dpdk-socket-limit
                                     optional string
         other_config : dpdk-hugepage-dir
                                     optional string
         other_config : dpdk-extra   optional string
         other_config : vhost-sock-dir
                                     optional string
         other_config : vhost-iommu-support
                                     optional string, either true or false
         other_config : per-port-memory
                                     optional string, either true or false
         other_config : tx-flush-interval
                                     optional  string,  containing an integer,
                                     in range 0 to 1,000,000
         other_config : pmd-perf-metrics
                                     optional string, either true or false
         other_config : smc-enable   optional string, either true or false
         other_config : pmd-rxq-assign
                                     optional   string,   either   cycles   or
                                     roundrobin
         other_config : n-handler-threads
                                     optional  string,  containing an integer,
                                     at least 1
         other_config : n-revalidator-threads
                                     optional string, containing  an  integer,
                                     at least 1
         other_config : emc-insert-inv-prob
                                     optional  string,  containing an integer,
                                     in range 0 to 4,294,967,295
         other_config : vlan-limit   optional string, containing  an  integer,
                                     at least 0
         other_config : bundle-idle-timeout
                                     optional  string,  containing an integer,
                                     at least 1
         other_config : offload-rebalance
                                     optional string, either true or false
         other_config : pmd-auto-lb  optional string, either true or false
         other_config : pmd-auto-lb-rebal-interval
                                     optional string, containing  an  integer,
                                     in range 0 to 20,000
       Status:
         next_cfg                    integer
         cur_cfg                     integer
         dpdk_initialized            boolean
         Statistics:
            other_config : enable-statistics
                                     optional string, either true or false
            statistics : cpu         optional  string,  containing an integer,
                                     at least 1
            statistics : load_average
                                     optional string
            statistics : memory      optional string
            statistics : process_NAME
                                     optional string
            statistics : file_systems
                                     optional string
       Version Reporting:
         ovs_version                 optional string
         db_version                  optional string
         system_type                 optional string
         system_version              optional string
         dpdk_version                optional string
       Capabilities:
         datapath_types              set of strings
         iface_types                 set of strings
       Database Configuration:
         manager_options             set of Managers
       IPsec:
         other_config : private_key  optional string
         other_config : certificate  optional string
         other_config : ca_cert      optional string
         Plaintext Tunnel Policy:
            other_config : ipsec_skb_mark
                                     optional string
       Common Columns:
         other_config                map of string-string pairs
         external_ids                map of string-string pairs

   Details:
     Configuration:

       bridges: set of Bridges
              Set of bridges managed by the daemon.

       ssl: optional SSL
              SSL used globally by the daemon.

       external_ids : system-id: optional string
              A unique identifier for the Open vSwitch’s  physical  host.  The
              form  of  the  identifier  depends on the type of the host. On a
              Citrix XenServer,  this  will  likely  be  the  same  as  exter
              nal_ids:xs-system-uuid.

       external_ids : xs-system-uuid: optional string
              The Citrix XenServer universally unique identifier for the phys‐
              ical host as displayed by xe host-list.

       external_ids : hostname: optional string
              The hostname for the host running Open vSwitch. This is a  fully
              qualified domain name since version 2.6.2.

       external_ids : rundir: optional string
              In  Open vSwitch 2.8 and later, the run directory of the running
              Open vSwitch daemon. This directory is used  for  runtime  state
              such  as control and management sockets. The value of other_con
              fig:vhost-sock-dir is relative to this directory.

       other_config : stats-update-interval: optional  string,  containing  an
       integer, at least 5,000
              Interval  for  updating statistics to the database, in millisec‐
              onds. This option will affect the update of the statistics  col‐
              umn in the following tables: Port, Interface , Mirror.

              Default value is 5000 ms.

              Getting statistics more frequently can be achieved via OpenFlow.

       other_config : flow-restore-wait: optional string, either true or false
              When  ovs-vswitchd  starts  up,  it  has an empty flow table and
              therefore it handles all arriving packets in its default fashion
              according to its configuration, by dropping them or sending them
              to an OpenFlow controller or  switching  them  as  a  standalone
              switch.  This  behavior  is  ordinarily  desirable.  However, if
              ovs-vswitchd is restarting as part of  a  ``hot-upgrade,’’  then
              this  leads to a relatively long period during which packets are
              mishandled.

              This option allows for  improvement.  When  ovs-vswitchd  starts
              with  this  value  set  as true, it will neither flush or expire
              previously set datapath flows nor will it send and  receive  any
              packets to or from the datapath. When this value is later set to
              false, ovs-vswitchd will start receiving packets from the  data‐
              path and re-setup the flows.

              Additionally,  ovs-vswitchd is prevented from connecting to con‐
              trollers when this value is set  to  true.  This  prevents  con‐
              trollers  from making changes to the flow table in the middle of
              flow restoration, which could result in undesirable intermediate
              states.  Once  this  value has been set to false and the desired
              flow state has been restored, ovs-vswitchd will be able  to  re‐
              connect  to controllers and process any new flow table modifica‐
              tions.

              Thus, with this option,  the  procedure  for  a  hot-upgrade  of
              ovs-vswitchd becomes roughly the following:

              1.  Stop ovs-vswitchd.

              2.  Set other_config:flow-restore-wait to true.

              3.  Start ovs-vswitchd.

              4.  Use  ovs-ofctl  (or  some other program, such as an OpenFlow
                  controller) to restore the OpenFlow flow table  to  the  de‐
                  sired state.

              5.  Set  other_config:flow-restore-wait  to  false (or remove it
                  entirely from the database).

              The ovs-ctl’s ``restart’’  and  ``force-reload-kmod’’  functions
              use the above config option during hot upgrades.

       other_config  :  flow-limit: optional string, containing an integer, at
       least 0
              The maximum number of flows allowed in the datapath flow  table.
              Internally  OVS  will  choose  a flow limit which will likely be
              lower than this number, based on real time  network  conditions.
              Tweaking  this value is discouraged unless you know exactly what
              you’re doing.

              The default is 200000.

       other_config : max-idle: optional string,  containing  an  integer,  at
       least 500
              The  maximum  time (in ms) that idle flows will remain cached in
              the datapath. Internally OVS will check the validity and  activ‐
              ity  for  datapath  flows regularly and may expire flows quicker
              than this number, based on real time network conditions.  Tweak‐
              ing  this  value  is  discouraged  unless  you know exactly what
              you’re doing.

              The default is 10000.

       other_config : hw-offload: optional string, either true or false
              Set this value to true to enable netdev flow offload.

              The  default  value  is  false.  Changing  this  value  requires
              restarting the daemon

              Currently  Open  vSwitch  supports  hardware offloading on Linux
              systems. On other systems, this value is ignored. This function‐
              ality  is considered ’experimental’. Depending on which OpenFlow
              matches and actions are  configured,  which  kernel  version  is
              used,  and  what  hardware is available, Open vSwitch may not be
              able to offload functionality to hardware.

       other_config : tc-policy: optional string, one  of  none,  skip_hw,  or
       skip_sw
              Specified the policy used with HW offloading. Options:

              none   Add software rule and offload rule to HW.

              skip_sw
                     Offload rule to HW only.

              skip_hw
                     Add software rule without offloading rule to HW.

              This is only relevant if other_config:hw-offload is enabled.

              The default value is none.

       other_config : dpdk-init: optional string, one of false, true, or try
              Set this value to true or try to enable runtime support for DPDK
              ports. The vswitch must have compile-time support  for  DPDK  as
              well.

              A  value of true will cause the ovs-vswitchd process to abort if
              DPDK cannot be initialized. A value of try will allow  the  ovs-
              vswitchd process to continue running even if DPDK cannot be ini‐
              tialized.

              The  default  value  is  false.  Changing  this  value  requires
              restarting the daemon

              If this value is false at startup, any dpdk ports which are con‐
              figured in the bridge will fail due to memory errors.

       other_config : dpdk-lcore-mask: optional string, containing an integer,
       at least 1
              Specifies  the  CPU  cores  where  dpdk  lcore threads should be
              spawned. The DPDK lcore threads are used for DPDK library tasks,
              such as library internal message processing, logging, etc. Value
              should be in the form of a hex string (so  ’0x123’)  similar  to
              the ’taskset’ mask input.

              The  lowest  order  bit corresponds to the first CPU core. A set
              bit means the corresponding  core  is  available  and  an  lcore
              thread  will  be created and pinned to it. If the input does not
              cover all cores, those uncovered cores are considered not set.

              For performance reasons, it is best to set this to a single core
              on the system, rather than allow lcore threads to float.

              If  not  specified, the value will be determined by choosing the
              lowest CPU core from initial cpu affinity list.  Otherwise,  the
              value will be passed directly to the DPDK library.

       other_config : pmd-cpu-mask: optional string
              Specifies  CPU  mask  for  setting the cpu affinity of PMD (Poll
              Mode Driver) threads. Value should be in the form of hex string,
              similar  to  the  dpdk  EAL  ’-c  COREMASK’  option input or the
              ’taskset’ mask input.

              The lowest order bit corresponds to the first CPU  core.  A  set
              bit  means  the corresponding core is available and a pmd thread
              will be created and pinned to it. If the input  does  not  cover
              all cores, those uncovered cores are considered not set.

              If  not  specified, one pmd thread will be created for each numa
              node and pinned to any available core on the numa  node  by  de‐
              fault.

       other_config  : dpdk-alloc-mem: optional string, containing an integer,
       at least 0
              Specifies the amount of memory to preallocate from the  hugepage
              pool,  regardless of socket. It is recommended that dpdk-socket-
              mem is used instead.

       other_config : dpdk-socket-mem: optional string
              Specifies the amount of memory to preallocate from the  hugepage
              pool, on a per-socket basis.

              The specifier is a comma-separated string, in ascending order of
              CPU socket. E.g. On a four socket system 1024,0,2048  would  set
              socket  0  to  preallocate  1024MB, socket 1 to preallocate 0MB,
              socket 2 to preallocate 2048MB and socket 3 (no value given)  to
              preallocate 0MB.

              If  dpdk-socket-mem  and dpdk-alloc-mem are not specified, dpdk-
              socket-mem will be used and the default value is 1024  for  each
              numa  node.  If dpdk-socket-mem and dpdk-alloc-mem are specified
              at same time, dpdk-socket-mem will be used as default.  Changing
              this value requires restarting the daemon.

       other_config : dpdk-socket-limit: optional string
              Limits  the  maximum  amount of memory that can be used from the
              hugepage pool, on a per-socket basis.

              The specifier is a comma-separated list  of  memory  limits  per
              socket. 0 will disable the limit for a particular socket.

              If  not specified, OVS will configure limits equal to the amount
              of preallocated memory specified by other_config:dpdk-socket-mem
              or --socket-mem in other_config:dpdk-extra. If none of the above
              options specified or --legacy-mem provided in other_config:dpdk-
              extra,  limits will not be applied. Changing this value requires
              restarting the daemon.

       other_config : dpdk-hugepage-dir: optional string
              Specifies the path to the hugetlbfs mount point.

              If not specified, this will be guessed by the DPDK library  (de‐
              fault  is /dev/hugepages). Changing this value requires restart‐
              ing the daemon.

       other_config : dpdk-extra: optional string
              Specifies additional eal command line arguments for DPDK.

              The default is empty. Changing this  value  requires  restarting
              the daemon

       other_config : vhost-sock-dir: optional string
              Specifies a relative path from external_ids:rundir to the vhost-
              user unix domain socket files. If this value is unset, the sock‐
              ets are put directly in external_ids:rundir.

              Changing this value requires restarting the daemon.

       other_config  :  vhost-iommu-support:  optional  string, either true or
       false
              vHost IOMMU is a security feature,  which  restricts  the  vhost
              memory  that  a virtio device may access. vHost IOMMU support is
              disabled by default, due to a bug in QEMU implementations of the
              vhost REPLY_ACK protocol, (on which vHost IOMMU relies) prior to
              v2.9.1. Setting this value to true enables vHost  IOMMU  support
              for  vHost  User  Client  ports  in OvS-DPDK, starting from DPDK
              v17.11.

              Changing this value requires restarting the daemon.

       other_config : per-port-memory: optional string, either true or false
              By default OVS DPDK uses a shared memory model  wherein  devices
              that have the same MTU and socket values can share the same mem‐
              pool. Setting this value to true  changes  this  behaviour.  Per
              port memory allow DPDK devices to use private memory per device.
              This can provide greater transparency as  regards  memory  usage
              but potentially at the cost of greater memory requirements.

              Changing  this value requires restarting the daemon if dpdk-init
              has already been set to true.

       other_config : tx-flush-interval: optional string, containing an  inte‐
       ger, in range 0 to 1,000,000
              Specifies  the  time  in  microseconds that a packet can wait in
              output batch for sending i.e. amount of  time  that  packet  can
              spend  in an intermediate output queue before sending to netdev.
              This option can be used to configure balance between  throughput
              and  latency. Lower values decreases latency while higher values
              may be useful to achieve higher performance.

              Defaults to 0 i.e. instant packet sending (latency optimized).

       other_config : pmd-perf-metrics: optional string, either true or false
              Enables recording of detailed PMD performance metrics for analy‐
              sis  and trouble-shooting. This can have a performance impact in
              the order of 1%.

              Defaults to false but can be changed at any time.

       other_config : smc-enable: optional string, either true or false
              Signature match cache or SMC is a cache between EMC and megaflow
              cache. It does not store the full key of the flow, so it is more
              memory efficient comparing to EMC cache. SMC is especially  use‐
              ful when flow count is larger than EMC capacity.

              Defaults to false but can be changed at any time.

       other_config  :  pmd-rxq-assign:  optional  string,  either  cycles  or
       roundrobin
              Specifies how RX queues will be automatically  assigned  to  CPU
              cores. Options:

              cycles Rxqs  will  be sorted by order of measured processing cy‐
                     cles before being assigned to CPU cores.

              roundrobin
                     Rxqs will be round-robined across CPU cores.

              The default value is cycles.

              Changing this value will affect an  automatic  re-assignment  of
              Rxqs to CPUs. Note: Rxqs mapped to CPU cores with pmd-rxq-affin
              ity are unaffected.

       other_config : n-handler-threads: optional string, containing an  inte‐
       ger, at least 1
              Specifies  the  number  of threads for software datapaths to use
              for handling new flows. The default the  number  of  online  CPU
              cores minus the number of revalidators.

              This  configuration  is  per datapath. If you have more than one
              software datapath (e.g. some  system  bridges  and  some  netdev
              bridges),  then the total number of threads is n-handler-threads
              times the number of software datapaths.

       other_config : n-revalidator-threads: optional  string,  containing  an
       integer, at least 1
              Specifies  the  number  of threads for software datapaths to use
              for revalidating flows in the datapath. Typically,  there  is  a
              direct  correlation  between  the number of revalidator threads,
              and the number of flows allowed in the datapath. The default  is
              the  number  of  cpu  cores  divided by four plus one. If n-han
              dler-threads is set, the default changes to the  number  of  cpu
              cores minus the number of handler threads.

              This  configuration  is  per datapath. If you have more than one
              software datapath (e.g. some  system  bridges  and  some  netdev
              bridges),  then the total number of threads is n-handler-threads
              times the number of software datapaths.

       other_config : emc-insert-inv-prob: optional string, containing an  in‐
       teger, in range 0 to 4,294,967,295
              Specifies  the  inverse probability (1/emc-insert-inv-prob) of a
              flow being inserted into the Exact Match Cache (EMC). On average
              one  in every emc-insert-inv-prob packets that generate a unique
              flow will cause an insertion into the EMC. A value of 1 will re‐
              sult in an insertion for every flow (1/1 = 100%) whereas a value
              of zero will result in no insertions and essentially disable the
              EMC.

              Defaults  to  100 ie. there is (1/100 =) 1% chance of EMC inser‐
              tion.

       other_config : vlan-limit: optional string, containing an  integer,  at
       least 0
              Limits  the  number  of  VLAN headers that can be matched to the
              specified number. Further VLAN headers will be treated  as  pay‐
              load, e.g. a packet with more 802.1q headers will match Ethernet
              type 0x8100.

              Open vSwitch userspace currently supports at most 2  VLANs,  and
              each  datapath  has  its own limit. If vlan-limit is nonzero, it
              acts as a further limit.

              If this value is absent, the default is currently 1. This  main‐
              tains backward compatibility with controllers that were designed
              for use with Open vSwitch versions earlier than 2.8, which  only
              supported one VLAN.

       other_config  : bundle-idle-timeout: optional string, containing an in‐
       teger, at least 1
              The maximum time (in seconds) that idle bundles will wait to  be
              expired since it was either opened, modified or closed.

              OpenFlow  specification  mandates the timeout to be at least one
              second. The default is 10 seconds.

       other_config : offload-rebalance: optional string, either true or false
              Configures HW offload rebalancing, that  allows  to  dynamically
              offload  and  un-offload flows while an offload-device is out of
              resources (OOR). This policy allows flows to be selected for of‐
              floading based on the packets-per-second (pps) rate of flows.

              Set this value to true to enable this option.

              The  default  value  is  false.  Changing  this  value  requires
              restarting the daemon.

              This is only relevant if HW offloading is enabled  (hw-offload).
              When  this policy is enabled, it also requires ’tc-policy’ to be
              set to ’skip_sw’.

       other_config : pmd-auto-lb: optional string, either true or false
              Configures PMD Auto Load Balancing that allows automatic assign‐
              ment  of  RX  queues  to PMDs if any of PMDs is overloaded (i.e.
              processing cycles >gt; 95%).

              It uses current scheme of cycle based assignment  of  RX  queues
              that are not statically pinned to PMDs.

              The default value is false.

              Set  this  value  to true to enable this option. It is currently
              disabled by default and an experimental feature.

              This only comes in effect if cycle based assignment  is  enabled
              and  there  are  more  than one non-isolated PMDs present and at
              least one of it polls more than one queue.

       other_config : pmd-auto-lb-rebal-interval: optional string,  containing
       an integer, in range 0 to 20,000
              The  minimum  time (in minutes) 2 consecutive PMD Auto Load Bal‐
              ancing iterations.

              The defaul value is 1 min. If configured to 0 then it  would  be
              converted to default value i.e. 1 min

              This  option can be configured to avoid frequent trigger of auto
              load balancing of PMDs. For e.g. set the  value  (in  min)  such
              that it occurs once in few hours or a day or a week.

     Status:

       next_cfg: integer
              Sequence  number for client to increment. When a client modifies
              any part of the database configuration and wishes  to  wait  for
              Open  vSwitch  to  finish applying the changes, it may increment
              this sequence number.

       cur_cfg: integer
              Sequence number that Open vSwitch sets to the current  value  of
              next_cfg  after  it  finishes  applying  a  set of configuration
              changes.

       dpdk_initialized: boolean
              True if other_config:dpdk-init is set to true and the  DPDK  li‐
              brary is successfully initialized.

     Statistics:

       The  statistics  column contains key-value pairs that report statistics
       about a system running an Open vSwitch. These are updated  periodically
       (currently, every 5 seconds). Key-value pairs that cannot be determined
       or that do not apply to a platform are omitted.

       other_config : enable-statistics: optional string, either true or false
              Statistics are disabled by default to avoid overhead in the com‐
              mon case when statistics gathering is not useful. Set this value
              to true to enable populating the statistics column or  to  false
              to explicitly disable it.

       statistics : cpu: optional string, containing an integer, at least 1
              Number of CPU processors, threads, or cores currently online and
              available to the operating system on which Open vSwitch is  run‐
              ning, as an integer. This may be less than the number installed,
              if some are not online or if they are not available to the oper‐
              ating system.

              Open  vSwitch userspace processes are not multithreaded, but the
              Linux kernel-based datapath is.

       statistics : load_average: optional string
              A comma-separated list of three floating-point  numbers,  repre‐
              senting  the system load average over the last 1, 5, and 15 min‐
              utes, respectively.

       statistics : memory: optional string
              A comma-separated list of integers, each of which  represents  a
              quantity  of  memory  in  kilobytes that describes the operating
              system on which Open vSwitch is running.  In  respective  order,
              these values are:

              1.  Total amount of RAM allocated to the OS.

              2.  RAM allocated to the OS that is in use.

              3.  RAM  that  can be flushed out to disk or otherwise discarded
                  if that space is needed for another purpose. This number  is
                  necessarily less than or equal to the previous value.

              4.  Total disk space allocated for swap.

              5.  Swap space currently in use.

              On Linux, all five values can be determined and are included. On
              other operating systems, only the first two values can be deter‐
              mined, so the list will only have two values.

       statistics : process_NAME: optional string
              One  such  key-value pair, with NAME replaced by a process name,
              will exist for each running Open vSwitch  daemon  process,  with
              name  replaced by the daemon’s name (e.g. process_ovs-vswitchd).
              The value is a comma-separated list of  integers.  The  integers
              represent  the  following, with memory measured in kilobytes and
              durations in milliseconds:

              1.  The process’s virtual memory size.

              2.  The process’s resident set size.

              3.  The amount of user and  system  CPU  time  consumed  by  the
                  process.

              4.  The  number  of  times that the process has crashed and been
                  automatically restarted by the monitor.

              5.  The duration since the process was started.

              6.  The duration for which the process has been running.

              The interpretation of some of these values  depends  on  whether
              the  process was started with the --monitor. If it was not, then
              the crash count will always be 0 and the two durations will  al‐
              ways  be  the same. If --monitor was given, then the crash count
              may be positive; if it is, the latter duration is the amount  of
              time since the most recent crash and restart.

              There will be one key-value pair for each file in Open vSwitch’s
              ``run directory’’ (usually /var/run/openvswitch) whose name ends
              in .pid, whose contents are a process ID, and which is locked by
              a running process. The name is taken from the pidfile’s name.

              Currently Open vSwitch is only able to obtain all of  the  above
              detail  on  Linux  systems. On other systems, the same key-value
              pairs will be present but the values will always  be  the  empty
              string.

       statistics : file_systems: optional string
              A  space-separated  list  of information on local, writable file
              systems. Each item in the list describes  one  file  system  and
              consists in turn of a comma-separated list of the following:

              1.  Mount point, e.g. / or /var/log. Any spaces or commas in the
                  mount point are replaced by underscores.

              2.  Total size, in kilobytes, as an integer.

              3.  Amount of storage in use, in kilobytes, as an integer.

              This key-value pair is omitted if there are no  local,  writable
              file  systems or if Open vSwitch cannot obtain the needed infor‐
              mation.

     Version Reporting:

       These columns report the types and versions of the hardware  and  soft‐
       ware running Open vSwitch. We recommend in general that software should
       test whether specific features are supported instead of relying on ver‐
       sion  number  checks. These values are primarily intended for reporting
       to human administrators.

       ovs_version: optional string
              The Open vSwitch version number, e.g. 1.1.0.

       db_version: optional string
              The database schema  version  number,  e.g.  1.2.3.  See  ovsdb-
              tool(1) for an explanation of the numbering scheme.

              The  schema  version  is  part of the database schema, so it can
              also be retrieved by fetching the schema using the Open  vSwitch
              database protocol.

       system_type: optional string
              An  identifier  for  the  type  of  system  on top of which Open
              vSwitch runs, e.g. XenServer or KVM.

              System integrators are responsible for choosing and  setting  an
              appropriate value for this column.

       system_version: optional string
              The  version  of  the  system  identified  by  system_type, e.g.
              5.6.100-39265p on XenServer 5.6.100 build 39265.

              System integrators are responsible for choosing and  setting  an
              appropriate value for this column.

       dpdk_version: optional string
              The version of the linked DPDK library.

     Capabilities:

       These columns report capabilities of the Open vSwitch instance.

       datapath_types: set of strings
              This column reports the different dpifs registered with the sys‐
              tem. These are the values that this  instance  supports  in  the
              datapath_type column of the Bridge table.

       iface_types: set of strings
              This  column  reports  the different netdevs registered with the
              system. These are the values that this instance supports in  the
              type column of the Interface table.

     Database Configuration:

       These   columns   primarily   configure   the   Open  vSwitch  database
       (ovsdb-server), not the Open vSwitch switch (ovs-vswitchd).  The  OVSDB
       database also uses the ssl settings.

       The  Open vSwitch switch does read the database configuration to deter‐
       mine remote IP addresses to which in-band control should apply.

       manager_options: set of Managers
              Database clients to  which  the  Open  vSwitch  database  server
              should  connect or to which it should listen, along with options
              for how these connections should be configured. See the  Manager
              table for more information.

              For  this column to serve its purpose, ovsdb-server must be con‐
              figured to honor it. The easiest way to do  this  is  to  invoke
              ovsdb-server         with         the        option        --re
              mote=db:Open_vSwitch,Open_vSwitch,manager_options  The   startup
              scripts that accompany Open vSwitch do this by default.

     IPsec:

       These  settings  control the global configuration of IPsec tunnels. The
       options column of the Interface table configures IPsec  for  individual
       tunnels.

       OVS  IPsec  supports  the following three forms of authentication. Cur‐
       rently, all IPsec tunnels must use the same form:

              1.  Pre-shared keys: Omit the global settings. On  each  tunnel,
                  set options:psk.

              2.  Self-signed  certificates:  Set the private_key and certifi
                  cate  global  settings.  On  each  tunnel,  set  options:re
                  mote_cert. The remote certificate can be self-signed.

              3.  CA-signed  certificates:  Set all of the global settings. On
                  each tunnel, set options:remote_name to the common name (CN)
                  of  the  remote  certificate. The remote certificate must be
                  signed by the CA.

       other_config : private_key: optional string
              Name of a PEM file  containing  the  private  key  used  as  the
              switch’s identity for IPsec tunnels.

       other_config : certificate: optional string
              Name  of  a PEM file containing a certificate that certifies the
              switch’s private key, and identifies a  trustworthy  switch  for
              IPsec  tunnels. The certificate must be x.509 version 3 and with
              the string in common name (CN) also set in the subject  alterna‐
              tive name (SAN).

       other_config : ca_cert: optional string
              Name  of a PEM file containing the CA certificate used to verify
              that a remote switch of the IPsec tunnel is trustworthy.

     Plaintext Tunnel Policy:

       When an IPsec tunnel is configured in this database, multiple  indepen‐
       dent  components  take responsibility for implementing it. ovs-vswitchd
       and its datapath handle packet forwarding to the tunnel and a  separate
       daemon  pushes the tunnel’s IPsec policy configuration to the kernel or
       other entity that implements it. There is a race: if the former config‐
       uration  completes  before  the  latter, then packets sent by the local
       host over the tunnel can be transmitted in plaintext. Using  this  set‐
       ting, OVS users can avoid this undesirable situation.

       other_config : ipsec_skb_mark: optional string
              This setting takes the form value/mask. If it is specified, then
              the skb_mark field in every outgoing  tunneled  packet  sent  in
              plaintext  is compared against it and, if it matches, the packet
              is dropped. This is a global setting that is  applied  to  every
              tunneled  packet,  regardless of whether IPsec encryption is en‐
              abled for the tunnel, the type of tunnel, or whether OVS is  in‐
              volved.

              Example policies:

              1/1    Drop all unencrypted tunneled packets in which the least-
                     significant bit of skb_mark is 1. This would be a  useful
                     policy given an OpenFlow flow table that sets skb_mark to
                     1 for traffic  that  should  be  encrypted.  The  default
                     skb_mark is 0, so this would not affect other traffic.

              0/1    Drop all unencrypted tunneled packets in which the least-
                     significant bit of skb_mark is 0. This would be a  useful
                     policy if no unencrypted tunneled traffic should exit the
                     system without being  specially  whitelisted  by  setting
                     skb_mark to 1.

              (empty)
                     If  this  setting is empty or unset, then all unencrypted
                     tunneled packets are transmitted in the usual way.

     Common Columns:

       The overall purpose of these columns is described under Common  Columns
       at the beginning of this document.

       other_config: map of string-string pairs

       external_ids: map of string-string pairs

Bridge TABLE
       Configuration for a bridge within an Open_vSwitch.

       A  Bridge  record  represents  an  Ethernet  switch  with  one  or more
       ``ports,’’ which are the Port records pointed to by the Bridge’s  ports
       column.

   Summary:
       Core Features:
         name                        immutable  string  (must be unique within
                                     table)
         ports                       set of Ports
         mirrors                     set of Mirrors
         netflow                     optional NetFlow
         sflow                       optional sFlow
         ipfix                       optional IPFIX
         flood_vlans                 set of up to 4,096 integers, in  range  0
                                     to 4,095
         auto_attach                 optional AutoAttach
       OpenFlow Configuration:
         controller                  set of Controllers
         flow_tables                 map  of  integer-Flow_Table pairs, key in
                                     range 0 to 254
         fail_mode                   optional string, either secure or  stand
                                     alone
         datapath_id                 optional string
         datapath_version            string
         other_config : datapath-id  optional string
         other_config : dp-desc      optional string
         other_config : disable-in-band
                                     optional string, either true or false
         other_config : in-band-queue
                                     optional  string,  containing an integer,
                                     in range 0 to 4,294,967,295
         protocols                   set of strings, one of OpenFlow10,  Open
                                     Flow11,   OpenFlow12,  OpenFlow13,  Open
                                     Flow14, OpenFlow15, or OpenFlow16
       Spanning Tree Configuration:
         STP Configuration:
            stp_enable               boolean
            other_config : stp-system-id
                                     optional string
            other_config : stp-priority
                                     optional string, containing  an  integer,
                                     in range 0 to 65,535
            other_config : stp-hello-time
                                     optional  string,  containing an integer,
                                     in range 1 to 10
            other_config : stp-max-age
                                     optional string, containing  an  integer,
                                     in range 6 to 40
            other_config : stp-forward-delay
                                     optional  string,  containing an integer,
                                     in range 4 to 30
            other_config : mcast-snooping-aging-time
                                     optional string, containing  an  integer,
                                     at least 1
            other_config : mcast-snooping-table-size
                                     optional  string,  containing an integer,
                                     at least 1
            other_config : mcast-snooping-disable-flood-unregistered
                                     optional string, either true or false
         STP Status:
            status : stp_bridge_id   optional string
            status : stp_designated_root
                                     optional string
            status : stp_root_path_cost
                                     optional string
       Rapid Spanning Tree:
         RSTP Configuration:
            rstp_enable              boolean
            other_config : rstp-address
                                     optional string
            other_config : rstp-priority
                                     optional string, containing  an  integer,
                                     in range 0 to 61,440
            other_config : rstp-ageing-time
                                     optional  string,  containing an integer,
                                     in range 10 to 1,000,000
            other_config : rstp-force-protocol-version
                                     optional string, containing an integer
            other_config : rstp-max-age
                                     optional string, containing  an  integer,
                                     in range 6 to 40
            other_config : rstp-forward-delay
                                     optional  string,  containing an integer,
                                     in range 4 to 30
            other_config : rstp-transmit-hold-count
                                     optional string, containing  an  integer,
                                     in range 1 to 10
         RSTP Status:
            rstp_status : rstp_bridge_id
                                     optional string
            rstp_status : rstp_root_id
                                     optional string
            rstp_status : rstp_root_path_cost
                                     optional  string,  containing an integer,
                                     at least 0
            rstp_status : rstp_designated_id
                                     optional string
            rstp_status : rstp_designated_port_id
                                     optional string
            rstp_status : rstp_bridge_port_id
                                     optional string
       Multicast Snooping Configuration:
         mcast_snooping_enable       boolean
       Other Features:
         datapath_type               string
         external_ids : bridge-id    optional string
         external_ids : xs-network-uuids
                                     optional string
         other_config : hwaddr       optional string
         other_config : forward-bpdu
                                     optional string, either true or false
         other_config : mac-aging-time
                                     optional string, containing  an  integer,
                                     at least 1
         other_config : mac-table-size
                                     optional  string,  containing an integer,
                                     at least 1
       Common Columns:
         other_config                map of string-string pairs
         external_ids                map of string-string pairs

   Details:
     Core Features:

       name: immutable string (must be unique within table)
              Bridge identifier. Must be unique among the names of ports,  in‐
              terfaces, and bridges on a host.

              The  name  must  be alphanumeric and must not contain forward or
              backward slashes. The name of a bridge is also the  name  of  an
              Interface (and a Port) within the bridge, so the restrictions on
              the name column in the Interface table, particularly on  length,
              also  apply  to bridge names. Refer to the documentation for In
              terface names for details.

       ports: set of Ports
              Ports included in the bridge.

       mirrors: set of Mirrors
              Port mirroring configuration.

       netflow: optional NetFlow
              NetFlow configuration.

       sflow: optional sFlow
              sFlow(R) configuration.

       ipfix: optional IPFIX
              IPFIX configuration.

       flood_vlans: set of up to 4,096 integers, in range 0 to 4,095
              VLAN IDs of VLANs on which MAC address learning should  be  dis‐
              abled, so that packets are flooded instead of being sent to spe‐
              cific ports that are believed to  contain  packets’  destination
              MACs.  This should ordinarily be used to disable MAC learning on
              VLANs used for mirroring (RSPAN VLANs). It may  also  be  useful
              for debugging.

              SLB  bonding (see the bond_mode column in the Port table) is in‐
              compatible with flood_vlans. Consider using another bonding mode
              or a different type of mirror instead.

       auto_attach: optional AutoAttach
              Auto Attach configuration.

     OpenFlow Configuration:

       controller: set of Controllers
              OpenFlow  controller set. If unset, then no OpenFlow controllers
              will be used.

              If there are primary controllers, removing all  of  them  clears
              the OpenFlow flow tables, group table, and meter table. If there
              are no primary controllers, adding one also clears these tables.
              Other  changes  to the set of controllers, such as adding or re‐
              moving a service controller, adding another  primary  controller
              to  supplement  an existing primary controller, or removing only
              one of two primary controllers, have no effect on these tables.

       flow_tables: map of integer-Flow_Table pairs, key in range 0 to 254
              Configuration for OpenFlow tables. Each pair maps from an  Open‐
              Flow table ID to configuration for that table.

       fail_mode: optional string, either secure or standalone
              When  a controller is configured, it is, ordinarily, responsible
              for setting up all flows on the switch. Thus, if the  connection
              to  the  controller fails, no new network connections can be set
              up. If the connection to the controller stays down long  enough,
              no  packets can pass through the switch at all. This setting de‐
              termines the switch’s response to such a situation.  It  may  be
              set to one of the following:

              standalone
                     If  no  message is received from the controller for three
                     times  the  inactivity  probe  interval   (see   inactiv
                     ity_probe), then Open vSwitch will take over responsibil‐
                     ity for setting up flows.  In  this  mode,  Open  vSwitch
                     causes  the  bridge  to act like an ordinary MAC-learning
                     switch. Open vSwitch will continue to retry connecting to
                     the controller in the background and, when the connection
                     succeeds, it will discontinue its standalone behavior.

              secure Open vSwitch will not set up flows on its  own  when  the
                     controller  connection  fails  or when no controllers are
                     defined. The bridge will continue to retry connecting  to
                     any defined controllers forever.

              The default is standalone if the value is unset, but future ver‐
              sions of Open vSwitch may change the default.

              The standalone mode can create forwarding loops on a bridge that
              has  more  than  one uplink port unless STP is enabled. To avoid
              loops on such a bridge, configure secure mode or enable STP (see
              stp_enable).

              When  more  than one controller is configured, fail_mode is con‐
              sidered only when none of the configured controllers can be con‐
              tacted.

              Changing  fail_mode  when  no primary controllers are configured
              clears the OpenFlow flow tables, group table, and meter table.

       datapath_id: optional string
              Reports the OpenFlow datapath ID in use. Exactly 16 hex  digits.
              (Setting  this  column  has  no  useful  effect.  Set other-con
              fig:datapath-id instead.)

       datapath_version: string
              Reports the version number of the Open vSwitch datapath in  use.
              This  allows management software to detect and report discrepan‐
              cies between Open vSwitch userspace and datapath versions.  (The
              ovs_version  column in the Open_vSwitch reports the Open vSwitch
              userspace version.) The version reported depends on the datapath
              in use:

              •      When  the  kernel  module  included  in  the Open vSwitch
                     source tree is used, this column reports the Open vSwitch
                     version from which the module was taken.

              •      When the kernel module that is part of the upstream Linux
                     kernel is used, this column reports unknown>gt;>gt;.

              •      When the datapath is built into the ovs-vswitchd  binary,
                     this column reports built-in>gt;>gt;. A built-in datapath is by
                     definition the same version  as  the  rest  of  the  Open
                     VSwitch userspace.

              •      Other  datapaths  (such  as  the Hyper-V kernel datapath)
                     currently report unknown>gt;>gt;.

              A version discrepancy between ovs-vswitchd and the  datapath  in
              use  is  not  normally  cause for alarm. The Open vSwitch kernel
              datapaths for Linux and Hyper-V, in particular, are designed for
              maximum inter-version compatibility: any userspace version works
              with with any kernel version. Some reasons do exist to insist on
              particular  user/kernel  pairings.  First, newer kernel versions
              add new features, that can only be used by new-enough userspace,
              e.g. VXLAN tunneling requires certain minimal userspace and ker‐
              nel versions. Second, as an extension to the first reason,  some
              newer kernel versions add new features for enhancing performance
              that only new-enough userspace versions can take advantage of.

       other_config : datapath-id: optional string
              Overrides the default OpenFlow datapath ID, setting  it  to  the
              specified  value  specified in hex. The value must either have a
              0x prefix or be exactly 16 hex digits long. May not be all-zero.

       other_config : dp-desc: optional string
              Human readable description of datapath.  It  is  a  maximum  256
              byte-long  free-form  string to describe the datapath for debug‐
              ging purposes, e.g. switch3 in room 3120.

       other_config : disable-in-band: optional string, either true or false
              If set to true, disable in-band control on the bridge regardless
              of controller and manager settings.

       other_config  :  in-band-queue: optional string, containing an integer,
       in range 0 to 4,294,967,295
              A queue ID as a nonnegative  integer.  This  sets  the  OpenFlow
              queue ID that will be used by flows set up by in-band control on
              this bridge. If unset, or if the port used by an in-band control
              flow  does not have QoS configured, or if the port does not have
              a queue with the specified ID, the default  queue  is  used  in‐
              stead.

       protocols:  set  of strings, one of OpenFlow10, OpenFlow11, OpenFlow12,
       OpenFlow13, OpenFlow14, OpenFlow15, or OpenFlow16
              List of OpenFlow protocols that may be used when  negotiating  a
              connection  with  a controller. OpenFlow 1.0, 1.1, 1.2, 1.3, and
              1.4 are enabled by default if this column is empty.

              OpenFlow 1.5 and 1.6 are not enabled by  default  because  their
              implementations  are missing features. In addition, the OpenFlow
              1.6 specification is still under development and thus subject to
              change.

     Spanning Tree Configuration:

       The IEEE 802.1D Spanning Tree Protocol (STP) is a network protocol that
       ensures loop-free topologies. It allows redundant links to be  included
       in  the  network  to provide automatic backup paths if the active links
       fails.

       These settings configure the slower-to-converge but still  widely  sup‐
       ported   version   of   Spanning  Tree  Protocol,  sometimes  known  as
       802.1D-1998. Open vSwitch also supports the newer Rapid  Spanning  Tree
       Protocol  (RSTP), documented later in the section titled Rapid Spanning
       Tree Configuration.

     STP Configuration:

       stp_enable: boolean
              Enable spanning tree on the bridge. By default, STP is  disabled
              on  bridges.  Bond, internal, and mirror ports are not supported
              and will not participate in the spanning tree.

              STP and RSTP are mutually exclusive. If both are  enabled,  RSTP
              will be used.

       other_config : stp-system-id: optional string
              The bridge’s STP identifier (the lower 48 bits of the bridge-id)
              in the form xx:xx:xx:xx:xx:xx. By default, the identifier is the
              MAC address of the bridge.

       other_config : stp-priority: optional string, containing an integer, in
       range 0 to 65,535
              The bridge’s relative priority value for  determining  the  root
              bridge  (the  upper 16 bits of the bridge-id). A bridge with the
              lowest bridge-id is elected the root. By default,  the  priority
              is 0x8000.

       other_config  : stp-hello-time: optional string, containing an integer,
       in range 1 to 10
              The interval between transmissions of hello messages  by  desig‐
              nated ports, in seconds. By default the hello interval is 2 sec‐
              onds.

       other_config : stp-max-age: optional string, containing an integer,  in
       range 6 to 40
              The  maximum  age  of  the information transmitted by the bridge
              when it is the root bridge, in seconds. By default, the  maximum
              age is 20 seconds.

       other_config  : stp-forward-delay: optional string, containing an inte‐
       ger, in range 4 to 30
              The delay to wait  between  transitioning  root  and  designated
              ports  to forwarding, in seconds. By default, the forwarding de‐
              lay is 15 seconds.

       other_config : mcast-snooping-aging-time: optional  string,  containing
       an integer, at least 1
              The maximum number of seconds to retain a multicast snooping en‐
              try for which no packets have been seen.  The  default  is  cur‐
              rently  300  seconds  (5  minutes).  The value, if specified, is
              forced into a reasonable range, currently 15 to 3600 seconds.

       other_config : mcast-snooping-table-size: optional  string,  containing
       an integer, at least 1
              The maximum number of multicast snooping addresses to learn. The
              default is currently 2048. The value, if  specified,  is  forced
              into a reasonable range, currently 10 to 1,000,000.

       other_config   :   mcast-snooping-disable-flood-unregistered:  optional
       string, either true or false
              If set to false, unregistered multicast packets are forwarded to
              all  ports.  If  set to true, unregistered multicast packets are
              forwarded to ports connected to multicast routers.

     STP Status:

       These key-value pairs  report  the  status  of  802.1D-1998.  They  are
       present only if STP is enabled (via the stp_enable column).

       status : stp_bridge_id: optional string
              The  bridge ID used in spanning tree advertisements, in the form
              xxxx.yyyyyyyyyyyy where the xs are the STP priority, the ys  are
              the STP system ID, and each x and y is a hex digit.

       status : stp_designated_root: optional string
              The  designated root for this spanning tree, in the same form as
              status:stp_bridge_id. If this bridge is the root, this will have
              the  same  value as status:stp_bridge_id, otherwise it will dif‐
              fer.

       status : stp_root_path_cost: optional string
              The path cost of reaching the designated bridge. A lower  number
              is  better. The value is 0 if this bridge is the root, otherwise
              it is higher.

     Rapid Spanning Tree:

       Rapid Spanning Tree Protocol (RSTP), like STP, is  a  network  protocol
       that  ensures loop-free topologies. RSTP superseded STP with the publi‐
       cation of 802.1D-2004. Compared to STP, RSTP converges more quickly and
       recovers more quickly from failures.

     RSTP Configuration:

       rstp_enable: boolean
              Enable  Rapid  Spanning  Tree on the bridge. By default, RSTP is
              disabled on bridges. Bond, internal, and mirror  ports  are  not
              supported and will not participate in the spanning tree.

              STP  and  RSTP are mutually exclusive. If both are enabled, RSTP
              will be used.

       other_config : rstp-address: optional string
              The bridge’s RSTP address (the lower 48 bits of  the  bridge-id)
              in  the  form  xx:xx:xx:xx:xx:xx. By default, the address is the
              MAC address of the bridge.

       other_config : rstp-priority: optional string, containing  an  integer,
       in range 0 to 61,440
              The  bridge’s  relative  priority value for determining the root
              bridge (the upper 16 bits of the bridge-id). A bridge  with  the
              lowest  bridge-id  is elected the root. By default, the priority
              is 0x8000 (32768). This value needs to be a  multiple  of  4096,
              otherwise it’s rounded to the nearest inferior one.

       other_config  :  rstp-ageing-time: optional string, containing an inte‐
       ger, in range 10 to 1,000,000
              The Ageing Time parameter for the Bridge. The default  value  is
              300 seconds.

       other_config : rstp-force-protocol-version: optional string, containing
       an integer
              The Force Protocol Version parameter for the  Bridge.  This  can
              take  the  value  0  (STP Compatibility mode) or 2 (the default,
              normal operation).

       other_config : rstp-max-age: optional string, containing an integer, in
       range 6 to 40
              The  maximum  age  of  the information transmitted by the Bridge
              when it is the Root Bridge. The default value is 20.

       other_config : rstp-forward-delay: optional string, containing an inte‐
       ger, in range 4 to 30
              The  delay used by STP Bridges to transition Root and Designated
              Ports to Forwarding. The default value is 15.

       other_config : rstp-transmit-hold-count: optional string, containing an
       integer, in range 1 to 10
              The  Transmit Hold Count used by the Port Transmit state machine
              to limit transmission rate. The default value is 6.

     RSTP Status:

       These key-value pairs  report  the  status  of  802.1D-2004.  They  are
       present only if RSTP is enabled (via the rstp_enable column).

       rstp_status : rstp_bridge_id: optional string
              The bridge ID used in rapid spanning tree advertisements, in the
              form x.yyy.zzzzzzzzzzzz where x is the RSTP priority, the ys are
              a  locally assigned system ID extension, the zs are the STP sys‐
              tem ID, and each x, y, or z is a hex digit.

       rstp_status : rstp_root_id: optional string
              The root of this spanning tree, in the same  form  as  rstp_sta
              tus:rstp_bridge_id.  If  this bridge is the root, this will have
              the same value as rstp_status:rstp_bridge_id, otherwise it  will
              differ.

       rstp_status : rstp_root_path_cost: optional string, containing an inte‐
       ger, at least 0
              The path cost of reaching the root. A lower  number  is  better.
              The  value  is  0  if  this  bridge is the root, otherwise it is
              higher.

       rstp_status : rstp_designated_id: optional string
              The  RSTP  designated  ID,  in  the  same  form   as   rstp_sta
              tus:rstp_bridge_id.

       rstp_status : rstp_designated_port_id: optional string
              The RSTP designated port ID, as a 4-digit hex number.

       rstp_status : rstp_bridge_port_id: optional string
              The RSTP bridge port ID, as a 4-digit hex number.

     Multicast Snooping Configuration:

       Multicast  snooping  (RFC  4541) monitors the Internet Group Management
       Protocol (IGMP) and Multicast Listener Discovery traffic between  hosts
       and  multicast  routers.  The  switch  uses  what IGMP and MLD snooping
       learns to forward multicast traffic only to interfaces  that  are  con‐
       nected  to  interested receivers. Currently it supports IGMPv1, IGMPv2,
       IGMPv3, MLDv1 and MLDv2 protocols.

       mcast_snooping_enable: boolean
              Enable multicast snooping on the bridge. For now, the default is
              disabled.

     Other Features:

       datapath_type: string
              Name  of datapath provider. The kernel datapath has type system.
              The userspace datapath has type netdev. A manager may  refer  to
              the  datapath_types  column of the Open_vSwitch table for a list
              of the types accepted by this Open vSwitch instance.

       external_ids : bridge-id: optional string
              A unique identifier of the bridge. On Citrix XenServer this will
              commonly be the same as external_ids:xs-network-uuids.

       external_ids : xs-network-uuids: optional string
              Semicolon-delimited  set of universally unique identifier(s) for
              the network with which this bridge is  associated  on  a  Citrix
              XenServer  host.  The  network identifiers are RFC 4122 UUIDs as
              displayed by, e.g., xe network-list.

       other_config : hwaddr: optional string
              An Ethernet address in the form  xx:xx:xx:xx:xx:xx  to  set  the
              hardware  address  of  the local port and influence the datapath
              ID.

       other_config : forward-bpdu: optional string, either true or false
              Controls forwarding of BPDUs and other  network  control  frames
              when  NORMAL action is invoked. When this option is false or un‐
              set, frames with reserved Ethernet addresses (see  table  below)
              will  not  be  forwarded.  When this option is true, such frames
              will not be treated specially.

              The above general rule has the following exceptions:

              •      If STP is enabled on the bridge (see the stp_enable  col‐
                     umn  in  the  Bridge table), the bridge processes all re‐
                     ceived STP packets and never passes them to  OpenFlow  or
                     forwards them. This is true even if STP is disabled on an
                     individual port.

              •      If LLDP is enabled on an interface (see the  lldp  column
                     in the Interface table), the interface processes received
                     LLDP packets and never passes them to  OpenFlow  or  for‐
                     wards them.

              Set this option to true if the Open vSwitch bridge connects dif‐
              ferent Ethernet networks and is not configured to participate in
              STP.

              This  option  affects packets with the following destination MAC
              addresses:

              01:80:c2:00:00:00
                     IEEE 802.1D Spanning Tree Protocol (STP).

              01:80:c2:00:00:01
                     IEEE Pause frame.

              01:80:c2:00:00:0x
                     Other reserved protocols.

              00:e0:2b:00:00:00
                     Extreme Discovery Protocol (EDP).

              00:e0:2b:00:00:04 and 00:e0:2b:00:00:06
                     Ethernet Automatic Protection Switching (EAPS).

              01:00:0c:cc:cc:cc
                     Cisco Discovery Protocol (CDP),  VLAN  Trunking  Protocol
                     (VTP),  Dynamic Trunking Protocol (DTP), Port Aggregation
                     Protocol (PAgP), and others.

              01:00:0c:cc:cc:cd
                     Cisco Shared Spanning Tree Protocol PVSTP+.

              01:00:0c:cd:cd:cd
                     Cisco STP Uplink Fast.

              01:00:0c:00:00:00
                     Cisco Inter Switch Link.

              01:00:0c:cc:cc:cx
                     Cisco CFM.

       other_config : mac-aging-time: optional string, containing an  integer,
       at least 1
              The maximum number of seconds to retain a MAC learning entry for
              which no packets have been seen. The default  is  currently  300
              seconds  (5  minutes). The value, if specified, is forced into a
              reasonable range, currently 15 to 3600 seconds.

              A short MAC aging time allows a network to more  quickly  detect
              that a host is no longer connected to a switch port. However, it
              also makes it more likely that packets will be flooded  unneces‐
              sarily,  when they are addressed to a connected host that rarely
              transmits packets. To reduce the incidence of unnecessary flood‐
              ing,  use  a  MAC aging time longer than the maximum interval at
              which a host will ordinarily transmit packets.

       other_config : mac-table-size: optional string, containing an  integer,
       at least 1
              The  maximum  number  of  MAC addresses to learn. The default is
              currently 8192. The value, if specified, is forced into  a  rea‐
              sonable range, currently 10 to 1,000,000.

     Common Columns:

       The  overall purpose of these columns is described under Common Columns
       at the beginning of this document.

       other_config: map of string-string pairs

       external_ids: map of string-string pairs

Port TABLE
       A port within a Bridge.

       Most commonly, a port has exactly one ``interface,’’ pointed to by  its
       interfaces  column.  Such  a  port logically corresponds to a port on a
       physical Ethernet switch. A port with more  than  one  interface  is  a
       ``bonded port’’ (see Bonding Configuration).

       Some  properties  that one might think as belonging to a port are actu‐
       ally part of the port’s Interface members.

   Summary:
       name                          immutable string (must be  unique  within
                                     table)
       interfaces                    set of 1 or more Interfaces
       VLAN Configuration:
         vlan_mode                   optional    string,    one   of   access,
                                     dot1q-tunnel,  native-tagged,  native-un
                                     tagged, or trunk
         tag                         optional integer, in range 0 to 4,095
         trunks                      set  of  up to 4,096 integers, in range 0
                                     to 4,095
         cvlans                      set of up to 4,096 integers, in  range  0
                                     to 4,095
         other_config : qinq-ethtype
                                     optional string, either 802.1ad or 802.1q
         other_config : priority-tags
                                     optional string, either true or false
       Bonding Configuration:
         bond_mode                   optional  string,  one  of active-backup,
                                     balance-slb, or balance-tcp
         other_config : bond-hash-basis
                                     optional string, containing an integer
         Link Failure Detection:
            other_config : bond-detect-mode
                                     optional string, either carrier or miimon
            other_config : bond-miimon-interval
                                     optional string, containing an integer
            bond_updelay             integer
            bond_downdelay           integer
         LACP Configuration:
            lacp                     optional string, one of active,  off,  or
                                     passive
            other_config : lacp-system-id
                                     optional string
            other_config : lacp-system-priority
                                     optional  string,  containing an integer,
                                     in range 1 to 65,535
            other_config : lacp-time optional string, either fast or slow
            other_config : lacp-fallback-ab
                                     optional string, either true or false
         Rebalancing Configuration:
            other_config : bond-rebalance-interval
                                     optional string, containing  an  integer,
                                     in range 0 to 10,000
         bond_fake_iface             boolean
       Spanning Tree Protocol:
         STP Configuration:
            other_config : stp-enable
                                     optional string, either true or false
            other_config : stp-port-num
                                     optional  string,  containing an integer,
                                     in range 1 to 255
            other_config : stp-port-priority
                                     optional string, containing  an  integer,
                                     in range 0 to 255
            other_config : stp-path-cost
                                     optional  string,  containing an integer,
                                     in range 0 to 65,535
         STP Status:
            status : stp_port_id     optional string
            status : stp_state       optional string, one  of  blocking,  dis
                                     abled, forwarding, learning, or listening
            status : stp_sec_in_state
                                     optional  string,  containing an integer,
                                     at least 0
            status : stp_role        optional string, one of alternate, desig
                                     nated, or root
       Rapid Spanning Tree Protocol:
         RSTP Configuration:
            other_config : rstp-enable
                                     optional string, either true or false
            other_config : rstp-port-priority
                                     optional  string,  containing an integer,
                                     in range 0 to 240
            other_config : rstp-port-num
                                     optional string, containing  an  integer,
                                     in range 1 to 4,095
            other_config : rstp-port-path-cost
                                     optional string, containing an integer
            other_config : rstp-port-admin-edge
                                     optional string, either true or false
            other_config : rstp-port-auto-edge
                                     optional string, either true or false
            other_config : rstp-port-mcheck
                                     optional string, either true or false
         RSTP Status:
            rstp_status : rstp_port_id
                                     optional string
            rstp_status : rstp_port_role
                                     optional   string,   one   of  Alternate,
                                     Backup, Designated, Disabled, or Root
            rstp_status : rstp_port_state
                                     optional string, one  of  Disabled,  Dis
                                     carding, Forwarding, or Learning
            rstp_status : rstp_designated_bridge_id
                                     optional string
            rstp_status : rstp_designated_port_id
                                     optional string
            rstp_status : rstp_designated_path_cost
                                     optional string, containing an integer
         RSTP Statistics:
            rstp_statistics : rstp_tx_count
                                     optional integer
            rstp_statistics : rstp_rx_count
                                     optional integer
            rstp_statistics : rstp_error_count
                                     optional integer
            rstp_statistics : rstp_uptime
                                     optional integer
       Multicast Snooping:
         other_config : mcast-snooping-flood
                                     optional string, either true or false
         other_config : mcast-snooping-flood-reports
                                     optional string, either true or false
       Other Features:
         qos                         optional QoS
         mac                         optional string
         fake_bridge                 boolean
         protected                   boolean
         external_ids : fake-bridge-id-*
                                     optional string
         other_config : transient    optional string, either true or false
       bond_active_slave             optional string
       Port Statistics:
         Statistics: STP transmit and receive counters:
            statistics : stp_tx_count
                                     optional integer
            statistics : stp_rx_count
                                     optional integer
            statistics : stp_error_count
                                     optional integer
       Common Columns:
         other_config                map of string-string pairs
         external_ids                map of string-string pairs

   Details:
       name: immutable string (must be unique within table)
              Port name. For a non-bonded port, this should be the same as its
              interface’s name. Port names must otherwise be unique among  the
              names  of ports, interfaces, and bridges on a host. Because port
              and interfaces names are usually the same, the  restrictions  on
              the  name column in the Interface table, particularly on length,
              also apply to port names. Refer to the documentation for  Inter
              face names for details.

       interfaces: set of 1 or more Interfaces
              The  port’s  interfaces.  If  there  is more than one, this is a
              bonded Port.

     VLAN Configuration:

       In short, a VLAN (short for ``virtual LAN’’) is a way  to  partition  a
       single switch into multiple switches. VLANs can be confusing, so for an
       introduction, please refer to the question ``What’s a  VLAN?’’  in  the
       Open vSwitch FAQ.

       A  VLAN  is  sometimes  encoded into a packet using a 802.1Q or 802.1ad
       VLAN header, but every packet is part of some VLAN whether or not it is
       encoded  in  the packet. (A packet that appears to have no VLAN is part
       of VLAN 0, by default.) As a result, it’s useful to think of a VLAN  as
       a metadata property of a packet, separate from how the VLAN is encoded.
       For a given port, this column determines how the encoding of  a  packet
       that  ingresses  or egresses the port maps to the packet’s VLAN. When a
       packet enters the switch, its VLAN is determined based on  its  setting
       in  this  column  and its VLAN headers, if any, and then, conceptually,
       the VLAN headers are then stripped off. Conversely, when a packet exits
       the  switch,  its  VLAN  and the settings in this column determine what
       VLAN headers, if any, are pushed onto the packet before it egresses the
       port.

       The VLAN configuration in this column affects Open vSwitch only when it
       is doing ``normal switching.’’ It does not affect flows set  up  by  an
       OpenFlow controller, outside of the OpenFlow ``normal action.’’

       Bridge ports support the following types of VLAN configuration:

              trunk  A  trunk  port  carries  packets on one or more specified
                     VLANs specified in the trunks  column  (often,  on  every
                     VLAN).  A packet that ingresses on a trunk port is in the
                     VLAN specified in its 802.1Q header, or  VLAN  0  if  the
                     packet  has  no  802.1Q  header.  A  packet that egresses
                     through a trunk port will have an 802.1Q header if it has
                     a nonzero VLAN ID.

                     Any  packet  that ingresses on a trunk port tagged with a
                     VLAN that the port does not trunk is dropped.

              access An access port carries packets on exactly one VLAN speci‐
                     fied  in  the  tag column. Packets egressing on an access
                     port have no 802.1Q header.

                     Any packet with an 802.1Q header with a nonzero  VLAN  ID
                     that  ingresses  on an access port is dropped, regardless
                     of whether the VLAN ID in the header is the access port’s
                     VLAN ID.

              native-tagged
                     A native-tagged port resembles a trunk port, with the ex‐
                     ception that a packet without an 802.1Q header  that  in‐
                     gresses on a native-tagged port is in the ``native VLAN’’
                     (specified in the tag column).

              native-untagged
                     A native-untagged port resembles  a  native-tagged  port,
                     with  the  exception that a packet that egresses on a na‐
                     tive-untagged port in the native VLAN will  not  have  an
                     802.1Q header.

              dot1q-tunnel
                     A dot1q-tunnel port is somewhat like an access port. Like
                     an access port, it carries packets  on  the  single  VLAN
                     specified  in  the  tag  column and this VLAN, called the
                     service VLAN, does not appear in  an  802.1Q  header  for
                     packets that ingress or egress on the port. The main dif‐
                     ference lies in the behavior when packets that include  a
                     802.1Q header ingress on the port. Whereas an access port
                     drops such packets, a dot1q-tunnel port treats  these  as
                     double-tagged with the outer service VLAN tag and the in‐
                     ner customer VLAN taken from the  802.1Q  header.  Corre‐
                     spondingly,  to  egress  on the port, a packet outer VLAN
                     (or only VLAN) must  be  tag,  which  is  removed  before
                     egress, which exposes the inner (customer) VLAN if one is
                     present.

                     If cvlans is set, only allows packets  in  the  specified
                     customer VLANs.

       A  packet  will only egress through bridge ports that carry the VLAN of
       the packet, as described by the rules above.

       vlan_mode: optional string, one of access, dot1q-tunnel, native-tagged,
       native-untagged, or trunk
              The  VLAN mode of the port, as described above. When this column
              is empty, a default mode is selected as follows:

              •      If tag contains a value, the port is an access port.  The
                     trunks column should be empty.

              •      Otherwise,  the  port  is a trunk port. The trunks column
                     value is honored if it is present.

       tag: optional integer, in range 0 to 4,095
              For an access port, the port’s implicitly tagged VLAN. For a na‐
              tive-tagged  or  native-untagged  port,  the port’s native VLAN.
              Must be empty if this is a trunk port.

       trunks: set of up to 4,096 integers, in range 0 to 4,095
              For a trunk, native-tagged, or native-untagged port, the  802.1Q
              VLAN  or  VLANs  that this port trunks; if it is empty, then the
              port trunks all VLANs. Must be empty if this is an access port.

              A native-tagged or native-untagged port always trunks its native
              VLAN, regardless of whether trunks includes that VLAN.

       cvlans: set of up to 4,096 integers, in range 0 to 4,095
              For  a  dot1q-tunnel port, the customer VLANs that this port in‐
              cludes. If this is empty, the port includes all customer VLANs.

              For other kinds of ports, this setting is ignored.

       other_config : qinq-ethtype: optional string, either 802.1ad or 802.1q
              For a dot1q-tunnel port, this is the TPID for the  service  tag,
              that  is,  for  the 802.1Q header that contains the service VLAN
              ID. Because packets that actually ingress and  egress  a  dot1q-
              tunnel  port  do  not  include  an 802.1Q header for the service
              VLAN, this does not affect packets on the dot1q-tunnel port  it‐
              self.  Rather,  it determines the service VLAN for a packet that
              ingresses on a dot1q-tunnel port and egresses on a trunk port.

              The value 802.1ad specifies TPID 0x88a8, which is also  the  de‐
              fault if the setting is omitted. The value 802.1q specifies TPID
              0x8100.

              For other kinds of ports, this setting is ignored.

       other_config : priority-tags: optional string, either true or false
              An 802.1Q header contains two important pieces of information: a
              VLAN  ID  and  a priority. A frame with a zero VLAN ID, called a
              ``priority-tagged’’ frame, is supposed to be  treated  the  same
              way  as  a frame without an 802.1Q header at all (except for the
              priority).

              However, some network elements ignore any frame that has  802.1Q
              header  at all, even when the VLAN ID is zero. Therefore, by de‐
              fault Open vSwitch does not output priority-tagged  frames,  in‐
              stead  omitting  the  802.1Q  header  entirely if the VLAN ID is
              zero. Set this key to true to enable priority-tagged frames on a
              port.

              Regardless of this setting, Open vSwitch omits the 802.1Q header
              on output if both the VLAN ID and priority would be zero.

              All frames output to native-tagged ports have a nonzero VLAN ID,
              so this setting is not meaningful on native-tagged ports.

     Bonding Configuration:

       A  port  that has more than one interface is a ``bonded port.’’ Bonding
       allows for load balancing and fail-over.

       The following types of bonding will work  with  any  kind  of  upstream
       switch.  On  the  upstream switch, do not configure the interfaces as a
       bond:

              balance-slb
                     Balances flows among slaves based on source  MAC  address
                     and  output  VLAN,  with  periodic rebalancing as traffic
                     patterns change.

              active-backup
                     Assigns all flows to one slave, failing over to a  backup
                     slave when the active slave is disabled. This is the only
                     bonding mode in which interfaces may be plugged into dif‐
                     ferent upstream switches.

       The following modes require the upstream switch to support 802.3ad with
       successful LACP negotiation. If LACP negotiation fails  and  other-con‐
       fig:lacp-fallback-ab is true, then active-backup mode is used:

              balance-tcp
                     Balances  flows  among slaves based on L3 and L4 protocol
                     information such as IP addresses and TCP/UDP ports.

       These columns apply only to bonded ports. Their  values  are  otherwise
       ignored.

       bond_mode:  optional string, one of active-backup, balance-slb, or bal
       ance-tcp
              The type of bonding used for a  bonded  port.  Defaults  to  ac
              tive-backup if unset.

       other_config : bond-hash-basis: optional string, containing an integer
              An  integer  hashed along with flows when choosing output slaves
              in load balanced bonds. When changed, all flows will be assigned
              different hash values possibly causing slave selection decisions
              to change. Does not affect bonding modes  which  do  not  employ
              load balancing such as active-backup.

     Link Failure Detection:

       An  important  part of link bonding is detecting that links are down so
       that they may be disabled. These settings determine  how  Open  vSwitch
       detects link failure.

       other_config : bond-detect-mode: optional string, either carrier or mi
       imon
              The means used to detect  link  failures.  Defaults  to  carrier
              which uses each interface’s carrier to detect failures. When set
              to miimon, will check for failures by polling  each  interface’s
              MII.

       other_config : bond-miimon-interval: optional string, containing an in‐
       teger
              The interval, in milliseconds, between  successive  attempts  to
              poll each interface’s MII. Relevant only when other_config:bond-
              detect-mode is miimon.

       bond_updelay: integer
              The number of milliseconds for which the link must stay up on an
              interface before the interface is considered to be up. Specify 0
              to enable the interface immediately.

              This setting is honored only when at least one bonded  interface
              is  already  enabled.  When  no interfaces are enabled, then the
              first bond interface to come up is enabled immediately.

       bond_downdelay: integer
              The number of milliseconds for which the link must stay down  on
              an  interface  before  the  interface  is considered to be down.
              Specify 0 to disable the interface immediately.

     LACP Configuration:

       LACP, the Link Aggregation Control Protocol, is an IEEE  standard  that
       allows switches to automatically detect that they are connected by mul‐
       tiple links and aggregate across those links.  These  settings  control
       LACP behavior.

       lacp: optional string, one of active, off, or passive
              Configures  LACP  on  this  port. LACP allows directly connected
              switches to negotiate which links may be bonded. LACP may be en‐
              abled  on  non-bonded ports for the benefit of any switches they
              may be connected to. active ports are allowed to  initiate  LACP
              negotiations.  passive  ports are allowed to participate in LACP
              negotiations initiated by a remote switch, but  not  allowed  to
              initiate  such  negotiations themselves. If LACP is enabled on a
              port whose partner switch does not support LACP, the  bond  will
              be  disabled,  unless  other-config:lacp-fallback-ab  is  set to
              true. Defaults to off if unset.

       other_config : lacp-system-id: optional string
              The LACP system ID of this Port. The system ID of a LACP bond is
              used  to  identify itself to its partners. Must be a nonzero MAC
              address. Defaults to the bridge Ethernet address if unset.

       other_config : lacp-system-priority: optional string, containing an in‐
       teger, in range 1 to 65,535
              The  LACP  system  priority  of this Port. In LACP negotiations,
              link status decisions are made by the system  with  the  numeri‐
              cally lower priority.

       other_config : lacp-time: optional string, either fast or slow
              The  LACP  timing  which should be used on this Port. By default
              slow is used. When configured to be fast LACP heartbeats are re‐
              quested  at a rate of once per second causing connectivity prob‐
              lems to be detected more quickly. In slow mode,  heartbeats  are
              requested at a rate of once every 30 seconds.

       other_config : lacp-fallback-ab: optional string, either true or false
              Determines the behavior of openvswitch bond in LACP mode. If the
              partner switch does not support LACP,  setting  this  option  to
              true allows openvswitch to fallback to active-backup. If the op‐
              tion is set to false, the bond will be  disabled.  In  both  the
              cases,  once  the partner switch is configured to LACP mode, the
              bond will use LACP.

     Rebalancing Configuration:

       These settings control behavior when a bond is in balance-slb  or  bal
       ance-tcp mode.

       other_config  : bond-rebalance-interval: optional string, containing an
       integer, in range 0 to 10,000
              For a load balanced bonded port, the number of milliseconds  be‐
              tween  successive  attempts  to  rebalance the bond, that is, to
              move flows from one interface on the bond to another in  an  at‐
              tempt  to  keep  usage of each interface roughly equal. If zero,
              load balancing is disabled on the bond (link failure still cause
              flows to move). If less than 1000ms, the rebalance interval will
              be 1000ms.

       bond_fake_iface: boolean
              For a bonded port, whether to create a fake  internal  interface
              with  the  name  of  the  port.  Use only for compatibility with
              legacy software that requires this.

     Spanning Tree Protocol:

       The configuration here is only meaningful, and the status is only popu‐
       lated, when 802.1D-1998 Spanning Tree Protocol is enabled on the port’s
       Bridge with its stp_enable column.

     STP Configuration:

       other_config : stp-enable: optional string, either true or false
              When STP is enabled on a bridge, it is enabled by default on all
              of  the  bridge’s  ports except bond, internal, and mirror ports
              (which do not work with STP). If this column’s value  is  false,
              STP is disabled on the port.

       other_config : stp-port-num: optional string, containing an integer, in
       range 1 to 255
              The port number used for the lower 8 bits of the port-id. By de‐
              fault, the numbers will be assigned automatically. If any port’s
              number is manually configured on a bridge, then  they  must  all
              be.

       other_config  : stp-port-priority: optional string, containing an inte‐
       ger, in range 0 to 255
              The port’s relative priority value for determining the root port
              (the  upper  8 bits of the port-id). A port with a lower port-id
              will be chosen as the root port. By  default,  the  priority  is
              0x80.

       other_config  :  stp-path-cost: optional string, containing an integer,
       in range 0 to 65,535
              Spanning tree path cost for the port. A lower number indicates a
              faster  link. By default, the cost is based on the maximum speed
              of the link.

     STP Status:

       status : stp_port_id: optional string
              The port ID used in spanning tree advertisements for this  port,
              as  4  hex  digits.  Configuring the port ID is described in the
              stp-port-num and stp-port-priority keys of the other_config sec‐
              tion earlier.

       status  :  stp_state:  optional string, one of blocking, disabled, for
       warding, learning, or listening
              STP state of the port.

       status : stp_sec_in_state: optional string, containing an  integer,  at
       least 0
              The  amount of time this port has been in the current STP state,
              in seconds.

       status : stp_role: optional string, one of  alternate,  designated,  or
       root
              STP role of the port.

     Rapid Spanning Tree Protocol:

       The  configuration  here is only meaningful, and the status and statis‐
       tics are only populated, when 802.1D-1998 Spanning Tree Protocol is en‐
       abled on the port’s Bridge with its stp_enable column.

     RSTP Configuration:

       other_config : rstp-enable: optional string, either true or false
              When  RSTP  is  enabled on a bridge, it is enabled by default on
              all of the bridge’s ports  except  bond,  internal,  and  mirror
              ports  (which  do not work with RSTP). If this column’s value is
              false, RSTP is disabled on the port.

       other_config : rstp-port-priority: optional string, containing an inte‐
       ger, in range 0 to 240
              The  port’s  relative  priority  value  for determining the root
              port, in multiples of 16. By default, the port priority is  0x80
              (128). Any value in the lower 4 bits is rounded off. The signif‐
              icant upper 4 bits become the upper 4 bits  of  the  port-id.  A
              port with the lowest port-id is elected as the root.

       other_config  :  rstp-port-num: optional string, containing an integer,
       in range 1 to 4,095
              The local RSTP port number, used as the lower  12  bits  of  the
              port-id. By default the port numbers are assigned automatically,
              and typically may not correspond to the OpenFlow port numbers. A
              port with the lowest port-id is elected as the root.

       other_config  : rstp-port-path-cost: optional string, containing an in‐
       teger
              The port path cost. The Port’s contribution, when it is the Root
              Port,  to the Root Path Cost for the Bridge. By default the cost
              is automatically calculated from the port’s speed.

       other_config : rstp-port-admin-edge: optional string,  either  true  or
       false
              The admin edge port parameter for the Port. Default is false.

       other_config  :  rstp-port-auto-edge:  optional  string, either true or
       false
              The auto edge port parameter for the Port. Default is true.

       other_config : rstp-port-mcheck: optional string, either true or false
              The mcheck port parameter for the Port. Default is false. May be
              set to force the Port Protocol Migration state machine to trans‐
              mit RST BPDUs for a MigrateTime period, to test whether all  STP
              Bridges  on  the attached LAN have been removed and the Port can
              continue to transmit RSTP BPDUs. Setting mcheck has no effect if
              the Bridge is operating in STP Compatibility mode.

              Changing  the  value from true to false has no effect, but needs
              to be done if this behavior is to be triggered again  by  subse‐
              quently changing the value from false to true.

     RSTP Status:

       rstp_status : rstp_port_id: optional string
              The  port ID used in spanning tree advertisements for this port,
              as 4 hex digits. Configuring the port ID  is  described  in  the
              rstp-port-num  and  rstp-port-priority  keys of the other_config
              section earlier.

       rstp_status  :  rstp_port_role:  optional  string,  one  of  Alternate,
       Backup, Designated, Disabled, or Root
              RSTP role of the port.

       rstp_status  :  rstp_port_state: optional string, one of Disabled, Dis
       carding, Forwarding, or Learning
              RSTP state of the port.

       rstp_status : rstp_designated_bridge_id: optional string
              The port’s RSTP designated  bridge  ID,  in  the  same  form  as
              rstp_status:rstp_bridge_id in the Bridge table.

       rstp_status : rstp_designated_port_id: optional string
              The port’s RSTP designated port ID, as 4 hex digits.

       rstp_status : rstp_designated_path_cost: optional string, containing an
       integer
              The port’s RSTP designated path cost. Lower is better.

     RSTP Statistics:

       rstp_statistics : rstp_tx_count: optional integer
              Number of RSTP BPDUs transmitted through this port.

       rstp_statistics : rstp_rx_count: optional integer
              Number of valid RSTP BPDUs received by this port.

       rstp_statistics : rstp_error_count: optional integer
              Number of invalid RSTP BPDUs received by this port.

       rstp_statistics : rstp_uptime: optional integer
              The duration covered by the other RSTP statistics, in seconds.

     Multicast Snooping:

       other_config : mcast-snooping-flood: optional string,  either  true  or
       false
              If  set to true, multicast packets (except Reports) are uncondi‐
              tionally forwarded to the specific port.

       other_config : mcast-snooping-flood-reports:  optional  string,  either
       true or false
              If  set to true, multicast Reports are unconditionally forwarded
              to the specific port.

     Other Features:

       qos: optional QoS
              Quality of Service configuration for this port.

       mac: optional string
              The MAC address to use for this port for the purpose of choosing
              the  bridge’s  MAC address. This column does not necessarily re‐
              flect the port’s actual MAC address, nor will setting it  change
              the port’s actual MAC address.

       fake_bridge: boolean
              Does this port represent a sub-bridge for its tagged VLAN within
              the Bridge? See ovs-vsctl(8) for more information.

       protected: boolean
              The protected ports feature allows certain ports  to  be  desig‐
              nated  as protected. Traffic between protected ports is blocked.
              Protected ports can send traffic to  unprotected  ports.  Unpro‐
              tected ports can send traffic to any port. Default is false.

       external_ids : fake-bridge-id-*: optional string
              External  IDs for a fake bridge (see the fake_bridge column) are
              defined  by   prefixing   a   Bridge   external_ids   key   with
              fake-bridge-, e.g. fake-bridge-xs-network-uuids.

       other_config : transient: optional string, either true or false
              If  set  to  true,  the  port will be removed when ovs-ctl start
              --delete-transient-ports is used.

       bond_active_slave: optional string
              For a bonded port, record the mac address of the current  active
              slave.

     Port Statistics:

       Key-value  pairs that report port statistics. The update period is con‐
       trolled by other_config:stats-update-interval in the  Open_vSwitch  ta‐
       ble.

     Statistics: STP transmit and receive counters:

       statistics : stp_tx_count: optional integer
              Number  of  STP BPDUs sent on this port by the spanning tree li‐
              brary.

       statistics : stp_rx_count: optional integer
              Number of STP BPDUs received on this port and  accepted  by  the
              spanning tree library.

       statistics : stp_error_count: optional integer
              Number of bad STP BPDUs received on this port. Bad BPDUs include
              runt packets and those with an unexpected protocol ID.

     Common Columns:

       The overall purpose of these columns is described under Common  Columns
       at the beginning of this document.

       other_config: map of string-string pairs

       external_ids: map of string-string pairs

Interface TABLE
       An interface within a Port.

   Summary:
       Core Features:
         name                        immutable  string  (must be unique within
                                     table)
         ifindex                     optional   integer,   in   range   0   to
                                     4,294,967,295
         mac_in_use                  optional string
         mac                         optional string
         error                       optional string
         OpenFlow Port Number:
            ofport                   optional integer
            ofport_request           optional integer, in range 1 to 65,279
       System-Specific Details:
         type                        string
       Tunnel Options:
         options : remote_ip         optional string
         options : local_ip          optional string
         options : in_key            optional string
         options : out_key           optional string
         options : dst_port          optional string
         options : key               optional string
         options : tos               optional string
         options : ttl               optional string
         options : df_default        optional string, either true or false
         options : egress_pkt_mark   optional string
         Tunnel Options: lisp only:
            options : packet_type    optional string, either legacy_l3 or ptap
         Tunnel Options: vxlan only:
            options : exts           optional string
            options : packet_type    optional   string,   one   of  legacy_l2,
                                     legacy_l3, or ptap
         Tunnel Options: gre only:
            options : packet_type    optional  string,   one   of   legacy_l2,
                                     legacy_l3, or ptap
            options : seq            optional string, either true or false
         Tunnel Options: gre, geneve, and vxlan:
            options : csum           optional string, either true or false
         Tunnel Options: IPsec:
            options : psk            optional string
            options : remote_cert    optional string
            options : remote_name    optional string
       Tunnel Options: erspan only:
         options : erspan_idx        optional string
         options : erspan_ver        optional string
         options : erspan_dir        optional string
         options : erspan_hwid       optional string
       Patch Options:
         options : peer              optional string
       PMD (Poll Mode Driver) Options:
         options : n_rxq             optional  string,  containing an integer,
                                     at least 1
         options : dpdk-devargs      optional string
         other_config : pmd-rxq-affinity
                                     optional string
         options : vhost-server-path
                                     optional string
         options : dq-zero-copy      optional string, either true or false
         options : n_rxq_desc        optional string, containing  an  integer,
                                     in range 1 to 4,096
         options : n_txq_desc        optional  string,  containing an integer,
                                     in range 1 to 4,096
       EMC (Exact Match Cache) Configuration:
         other_config : emc-enable   optional string, either true or false
       MTU:
         mtu                         optional integer
         mtu_request                 optional integer, at least 1
       Interface Status:
         admin_state                 optional string, either down or up
         link_state                  optional string, either down or up
         link_resets                 optional integer
         link_speed                  optional integer
         duplex                      optional string, either full or half
         lacp_current                optional boolean
         status                      map of string-string pairs
         status : driver_name        optional string
         status : driver_version     optional string
         status : firmware_version   optional string
         status : source_ip          optional string
         status : tunnel_egress_iface
                                     optional string
         status : tunnel_egress_iface_carrier
                                     optional string, either down or up
         dpdk:
            status : port_no         optional string
            status : numa_id         optional string
            status : min_rx_bufsize  optional string
            status : max_rx_pktlen   optional string
            status : max_rx_queues   optional string
            status : max_tx_queues   optional string
            status : max_mac_addrs   optional string
            status : max_hash_mac_addrs
                                     optional string
            status : max_vfs         optional string
            status : max_vmdq_pools  optional string
            status : if_type         optional string
            status : if_descr        optional string
            status : pci-vendor_id   optional string
            status : pci-device_id   optional string
       Statistics:
         Statistics: Successful transmit and receive counters:
            statistics : rx_packets  optional integer
            statistics : rx_bytes    optional integer
            statistics : tx_packets  optional integer
            statistics : tx_bytes    optional integer
         Statistics: Receive errors:
            statistics : rx_dropped  optional integer
            statistics : rx_frame_err
                                     optional integer
            statistics : rx_over_err optional integer
            statistics : rx_crc_err  optional integer
            statistics : rx_errors   optional integer
         Statistics: Transmit errors:
            statistics : tx_dropped  optional integer
            statistics : collisions  optional integer
            statistics : tx_errors   optional integer
       Ingress Policing:
         ingress_policing_rate       integer, at least 0
         ingress_policing_burst      integer, at least 0
       Bidirectional Forwarding Detection (BFD):
         BFD Configuration:
            bfd : enable             optional string, either true or false
            bfd : min_rx             optional string, containing  an  integer,
                                     at least 1
            bfd : min_tx             optional  string,  containing an integer,
                                     at least 1
            bfd : decay_min_rx       optional string, containing an integer
            bfd : forwarding_if_rx   optional string, either true or false
            bfd : cpath_down         optional string, either true or false
            bfd : check_tnl_key      optional string, either true or false
            bfd : bfd_local_src_mac  optional string
            bfd : bfd_local_dst_mac  optional string
            bfd : bfd_remote_dst_mac optional string
            bfd : bfd_src_ip         optional string
            bfd : bfd_dst_ip         optional string
            bfd : oam                optional string
            bfd : mult               optional string, containing  an  integer,
                                     in range 1 to 255
         BFD Status:
            bfd_status : state       optional string, one of admin_down, down,
                                     init, or up
            bfd_status : forwarding  optional string, either true or false
            bfd_status : diagnostic  optional string
            bfd_status : remote_state
                                     optional string, one of admin_down, down,
                                     init, or up
            bfd_status : remote_diagnostic
                                     optional string
            bfd_status : flap_count  optional  string,  containing an integer,
                                     at least 0
       Connectivity Fault Management:
         cfm_mpid                    optional integer
         cfm_flap_count              optional integer
         cfm_fault                   optional boolean
         cfm_fault_status : recv     none
         cfm_fault_status : rdi      none
         cfm_fault_status : maid     none
         cfm_fault_status : loopback
                                     none
         cfm_fault_status : overflow
                                     none
         cfm_fault_status : override
                                     none
         cfm_fault_status : interval
                                     none
         cfm_remote_opstate          optional string, either down or up
         cfm_health                  optional integer, in range 0 to 100
         cfm_remote_mpids            set of integers
         other_config : cfm_interval
                                     optional string, containing an integer
         other_config : cfm_extended
                                     optional string, either true or false
         other_config : cfm_demand   optional string, either true or false
         other_config : cfm_opstate  optional string, either down or up
         other_config : cfm_ccm_vlan
                                     optional string, containing  an  integer,
                                     in range 1 to 4,095
         other_config : cfm_ccm_pcp  optional  string,  containing an integer,
                                     in range 1 to 7
       Bonding Configuration:
         other_config : lacp-port-id
                                     optional string, containing  an  integer,
                                     in range 1 to 65,535
         other_config : lacp-port-priority
                                     optional  string,  containing an integer,
                                     in range 1 to 65,535
         other_config : lacp-aggregation-key
                                     optional string, containing  an  integer,
                                     in range 1 to 65,535
       Virtual Machine Identifiers:
         external_ids : attached-mac
                                     optional string
         external_ids : iface-id     optional string
         external_ids : iface-status
                                     optional  string,  either active or inac
                                     tive
         external_ids : xs-vif-uuid  optional string
         external_ids : xs-network-uuid
                                     optional string
         external_ids : vm-id        optional string
         external_ids : xs-vm-uuid   optional string
       Auto Attach Configuration:
         lldp : enable               optional string, either true or false
       Flow control Configuration:
         options : rx-flow-ctrl      optional string, either true or false
         options : tx-flow-ctrl      optional string, either true or false
         options : flow-ctrl-autoneg
                                     optional string, either true or false
       Link State Change detection mode:
         options : dpdk-lsc-interrupt
                                     optional string, either true or false
       Common Columns:
         other_config                map of string-string pairs
         external_ids                map of string-string pairs

   Details:
     Core Features:

       name: immutable string (must be unique within table)
              Interface name. Should be  alphanumeric.  For  non-bonded  port,
              this  should  be the same as the port name. It must otherwise be
              unique among the names of ports, interfaces, and  bridges  on  a
              host.

              The  maximum length of an interface name depends on the underly‐
              ing datapath:

              •      The names of interfaces implemented as Linux and BSD net‐
                     work  devices,  including  interfaces with type internal,
                     tap, or system plus the different types of tunnel  ports,
                     are  limited  to  15 bytes. Windows limits these names to
                     255 bytes.

              •      The names of patch ports are not used in  the  underlying
                     datapath,  so operating system restrictions do not apply.
                     Thus, they may have arbitrary length.

              Regardless of other restrictions, OpenFlow only supports 15-byte
              names,  which means that ovs-ofctl and OpenFlow controllers will
              show names truncated to 15 bytes.

       ifindex: optional integer, in range 0 to 4,294,967,295
              A positive interface index as defined for SNMP  MIB-II  in  RFCs
              1213  and  2863,  if  the  interface  has  one, otherwise 0. The
              ifindex is useful for seamless integration with  protocols  such
              as SNMP and sFlow.

       mac_in_use: optional string
              The MAC address in use by this interface.

       mac: optional string
              Ethernet  address  to  set for this interface. If unset then the
              default MAC address is used:

              •      For the local interface, the default is  the  lowest-num‐
                     bered  MAC  address  among the other bridge ports, either
                     the value of the mac in its Port record, if set,  or  its
                     actual  MAC (for bonded ports, the MAC of its slave whose
                     name is first in alphabetical order). Internal ports  and
                     bridge ports that are used as port mirroring destinations
                     (see the Mirror table) are ignored.

              •      For other internal interfaces, the default  MAC  is  ran‐
                     domly generated.

              •      External  interfaces typically have a MAC address associ‐
                     ated with their hardware.

              Some interfaces may not have  a  software-controllable  MAC  ad‐
              dress.  This  option only affects internal ports. For other type
              ports, you can change the MAC address outside Open vSwitch,  us‐
              ing ip command.

       error: optional string
              If  the  configuration of the port failed, as indicated by -1 in
              ofport, Open vSwitch sets this column to an error description in
              human readable form. Otherwise, Open vSwitch clears this column.

     OpenFlow Port Number:

       When  a  client  adds a new interface, Open vSwitch chooses an OpenFlow
       port number for the new port. If the client that adds the port fills in
       ofport_request,  then  Open vSwitch tries to use its value as the Open‐
       Flow port number. Otherwise, or if the requested port number is already
       in use or cannot be used for another reason, Open vSwitch automatically
       assigns a free port number. Regardless of how the port number  was  ob‐
       tained,  Open  vSwitch  then reports in ofport the port number actually
       assigned.

       Open vSwitch limits the port numbers that it automatically  assigns  to
       the  range 1 through 32,767, inclusive. Controllers therefore have free
       use of ports 32,768 and up.

       ofport: optional integer
              OpenFlow port number for this interface. Open vSwitch sets  this
              column’s value, so other clients should treat it as read-only.

              The  OpenFlow  ``local’’  port (OFPP_LOCAL) is 65,534. The other
              valid port numbers are in the  range  1  to  65,279,  inclusive.
              Value -1 indicates an error adding the interface.

       ofport_request: optional integer, in range 1 to 65,279
              Requested OpenFlow port number for this interface.

              A  client  should  ideally  set  this column’s value in the same
              database transaction that it uses to create the interface.  Open
              vSwitch  version  2.1 and later will honor a later request for a
              specific port  number,  althuogh  it  might  confuse  some  con‐
              trollers: OpenFlow does not have a way to announce a port number
              change, so Open vSwitch represents it over OpenFlow  as  a  port
              deletion followed immediately by a port addition.

              If  ofport_request  is set or changed to some other port’s auto‐
              matically assigned port number, Open vSwitch chooses a new  port
              number for the latter port.

     System-Specific Details:

       type: string
              The interface type. The types supported by a particular instance
              of Open vSwitch are listed in  the  iface_types  column  in  the
              Open_vSwitch table. The following types are defined:

              system An ordinary network device, e.g. eth0 on Linux. Sometimes
                     referred to as ``external  interfaces’’  since  they  are
                     generally connected to hardware external to that on which
                     the Open vSwitch is running. The empty string is  a  syn‐
                     onym for system.

              internal
                     A  simulated network device that sends and receives traf‐
                     fic. An internal interface whose name is the same as  its
                     bridge’s  name is called the ``local interface.’’ It does
                     not make sense to bond  an  internal  interface,  so  the
                     terms  ``port’’  and  ``interface’’ are often used impre‐
                     cisely for internal interfaces.

              tap    A TUN/TAP device managed by Open vSwitch.

                     Open vSwitch checks the interface state before send pack‐
                     ets  to  the  device.  When  it  is down, the packets are
                     dropped and the tx_dropped statistic is  updated  accord‐
                     ingly.  Older  versions of Open vSwitch did not check the
                     interface state and then the tx_packets  was  incremented
                     along with tx_dropped.

              geneve An             Ethernet            over            Geneve
                     (http://tools.ietf.org/html/draft-ietf-nvo3-geneve)
                     IPv4/IPv6  tunnel.  A description of how to match and set
                     Geneve options can be found in the ovs-ofctl manual page.

              gre    Generic Routing Encapsulation (GRE) over  IPv4/IPv6  tun‐
                     nel, configurable to encapsulate layer 2 or layer 3 traf‐
                     fic.

              vxlan  An Ethernet tunnel over the UDP-based VXLAN protocol  de‐
                     scribed in RFC 7348.

                     Open  vSwitch  uses  IANA-assigned  UDP  destination port
                     4789. The source port used for VXLAN traffic varies on  a
                     per-flow basis and is in the ephemeral port range.

              lisp   A  layer  3 tunnel over the experimental, UDP-based Loca‐
                     tor/ID Separation Protocol (RFC 6830).

                     Only IPv4 and IPv6 packets are supported by the protocol,
                     and  they  are  sent  and  received  without  an Ethernet
                     header. Traffic to/from LISP ports is expected to be con‐
                     figured  explicitly,  and  the  ports are not intended to
                     participate in learning based switching.  As  such,  they
                     are always excluded from packet flooding.

              stt    The  Stateless  TCP  Tunnel  (STT) is particularly useful
                     when tunnel endpoints are in end-systems, as it  utilizes
                     the  capabilities  of standard network interface cards to
                     improve performance. STT utilizes a TCP-like  header  in‐
                     side  the  IP  header. It is stateless, i.e., there is no
                     TCP connection state of any kind associated with the tun‐
                     nel. The TCP-like header is used to leverage the capabil‐
                     ities of existing network interface cards, but should not
                     be  interpreted  as implying any sort of connection state
                     between endpoints. Since the STT protocol does not engage
                     in  the usual TCP 3-way handshake, so it will have diffi‐
                     culty traversing stateful firewalls. The protocol is doc‐
                     umented   at  https://tools.ietf.org/html/draft-davie-stt
                     All traffic uses a default destination port of 7471.

              patch  A pair of virtual devices that act as a patch cable.

     Tunnel Options:

       These options apply to interfaces with type of geneve, gre, vxlan, lisp
       and stt.

       Each tunnel must be uniquely identified by the combination of type, op
       tions:remote_ip, options:local_ip, and options:in_key. If two ports are
       defined that are the same except one has an optional identifier and the
       other does not, the more specific one is matched first.  options:in_key
       is considered more specific than options:local_ip if a port defines one
       and another port defines the other.

       options : remote_ip: optional string
              Required. The remote tunnel endpoint, one of:

              •      An  IPv4  or  IPv6  address  (not  a  DNS   name),   e.g.
                     192.168.0.123. Only unicast endpoints are supported.

              •      The word flow. The tunnel accepts packets from any remote
                     tunnel endpoint. To process only packets from a  specific
                     remote tunnel endpoint, the flow entries may match on the
                     tun_src or tun_ipv6_srcfield. When sending packets  to  a
                     remote_ip=flow  tunnel,  the flow actions must explicitly
                     set the tun_dst or tun_ipv6_dst field to the  IP  address
                     of  the  desired  remote  tunnel  endpoint,  e.g.  with a
                     set_field action.

              The remote tunnel endpoint for any packet received from a tunnel
              is  available  in the tun_src field for matching in the flow ta‐
              ble.

       options : local_ip: optional string
              Optional. The tunnel destination IP that received  packets  must
              match.  Default  is to match all addresses. If specified, may be
              one of:

              •      An IPv4/IPv6 address (not a DNS name), e.g. 192.168.12.3.

              •      The word flow. The tunnel accepts packets sent to any  of
                     the  local  IP  addresses  of  the system running OVS. To
                     process only packets sent to a specific IP  address,  the
                     flow  entries  may  match  on the tun_dst or tun_ipv6_dst
                     field. When sending packets to  a  local_ip=flow  tunnel,
                     the  flow  actions  may  explicitly  set  the  tun_src or
                     tun_ipv6_src field to the desired IP address, e.g. with a
                     set_field  action.  However,  while  routing the tunneled
                     packet out, the local system may override  the  specified
                     address with the local IP address configured for the out‐
                     going system interface.

                     This option is valid only  for  tunnels  also  configured
                     with the remote_ip=flow option.

              The tunnel destination IP address for any packet received from a
              tunnel is available in the tun_dst  or  tun_ipv6_dst  field  for
              matching in the flow table.

       options : in_key: optional string
              Optional. The key that received packets must contain, one of:

              •      0.  The tunnel receives packets with no key or with a key
                     of 0. This is equivalent to specifying no  options:in_key
                     at all.

              •      A  positive  24-bit (for Geneve, VXLAN, and LISP), 32-bit
                     (for GRE) or 64-bit (for STT) number. The tunnel receives
                     only packets with the specified key.

              •      The  word  flow. The tunnel accepts packets with any key.
                     The key will be placed in the tun_id field  for  matching
                     in the flow table. The ovs-fields(7) manual page contains
                     additional information about matching fields in  OpenFlow
                     flows.

       options : out_key: optional string
              Optional. The key to be set on outgoing packets, one of:

              •      0. Packets sent through the tunnel will have no key. This
                     is equivalent to specifying no options:out_key at all.

              •      A positive 24-bit (for Geneve, VXLAN  and  LISP),  32-bit
                     (for  GRE)  or  64-bit  (for  STT)  number.  Packets sent
                     through the tunnel will have the specified key.

              •      The word flow. Packets sent through the tunnel will  have
                     the  key  set using the set_tunnel Nicira OpenFlow vendor
                     extension (0 is used in the absence of  an  action).  The
                     ovs-fields(7) manual page contains additional information
                     about the Nicira OpenFlow vendor extensions.

       options : dst_port: optional string
              Optional. The tunnel transport layer destination port,  for  UDP
              and TCP based tunnel protocols (Geneve, VXLAN, LISP, and STT).

       options : key: optional string
              Optional. Shorthand to set in_key and out_key at the same time.

       options : tos: optional string
              Optional. The value of the ToS bits to be set on the encapsulat‐
              ing packet. ToS is interpreted as DSCP and ECN  bits,  ECN  part
              must be zero. It may also be the word inherit, in which case the
              ToS will be copied from the inner packet if it is IPv4  or  IPv6
              (otherwise  it  will be 0). The ECN fields are always inherited.
              Default is 0.

       options : ttl: optional string
              Optional. The TTL to be set on the encapsulating packet. It  may
              also  be  the word inherit, in which case the TTL will be copied
              from the inner packet if it is IPv4 or IPv6 (otherwise  it  will
              be  the system default, typically 64). Default is the system de‐
              fault TTL.

       options : df_default: optional string, either true or false
              Optional. If enabled, the Don’t Fragment bit will be set on tun‐
              nel  outer  headers  to allow path MTU discovery. Default is en‐
              abled; set to false to disable.

       options : egress_pkt_mark: optional string
              Optional. The pkt_mark to be set on  the  encapsulating  packet.
              This  option  sets  packet  mark for the tunnel endpoint for all
              tunnel packets including tunnel monitoring.

     Tunnel Options: lisp only:

       options : packet_type: optional string, either legacy_l3 or ptap
              A LISP tunnel sends and receives only  IPv4  and  IPv6  packets.
              This  option controls what how the tunnel represents the packets
              that it sends and receives:

              •      By default, or if this option is  legacy_l3,  the  tunnel
                     represents  packets  as Ethernet frames for compatibility
                     with legacy OpenFlow controllers that expect this  behav‐
                     ior.

              •      If this option is ptap, the tunnel represents packets us‐
                     ing the packet_type mechanism introduced in OpenFlow 1.5.

     Tunnel Options: vxlan only:

       options : exts: optional string
              Optional. Comma separated list of optional VXLAN  extensions  to
              enable. The following extensions are supported:

              •      gbp:  VXLAN-GBP allows to transport the group policy con‐
                     text of a packet across the VXLAN tunnel to other network
                     peers.    See   the   description   of   tun_gbp_id   and
                     tun_gbp_flags in ovs-fields(7)  for  additional  informa‐
                     tion.
                     (https://tools.ietf.org/html/draft-smith-vxlan-group-pol
                     icy)

              •      gpe: Support for Generic Protocol Encapsulation in accor‐
                     dance             with             IETF             draft
                     https://tools.ietf.org/html/draft-ietf-nvo3-vxlan-gpe.
                     Without this option, a VXLAN packet  always  encapsulates
                     an  Ethernet frame. With this option, an VXLAN packet may
                     also encapsulate an IPv4, IPv6, NSH, or MPLS packet.

       options : packet_type: optional string, one of legacy_l2, legacy_l3, or
       ptap
              This  option controls what types of packets the tunnel sends and
              receives and how it represents them:

              •      By default, or if this option is  legacy_l2,  the  tunnel
                     sends and receives only Ethernet frames.

              •      If  this  option  is  legacy_l3, the tunnel sends and re‐
                     ceives only non-Ethernet (L3) packet, but the packets are
                     represented  as  Ethernet  frames  for compatibility with
                     legacy OpenFlow controllers that  expect  this  behavior.
                     This requires enabling gpe in options:exts.

              •      If  this  option is ptap, Open vSwitch represents packets
                     in the tunnel using the packet_type mechanism  introduced
                     in  OpenFlow  1.5.  This  mechanism  supports any kind of
                     packet, but actually sending and  receiving  non-Ethernet
                     packets   requires   additionally  enabling  gpe  in  op
                     tions:exts.

     Tunnel Options: gre only:

       gre interfaces support these options.

       options : packet_type: optional string, one of legacy_l2, legacy_l3, or
       ptap
              This  option controls what types of packets the tunnel sends and
              receives and how it represents them:

              •      By default, or if this option is  legacy_l2,  the  tunnel
                     sends and receives only Ethernet frames.

              •      If  this  option  is  legacy_l3, the tunnel sends and re‐
                     ceives only non-Ethernet (L3) packet, but the packets are
                     represented  as  Ethernet  frames  for compatibility with
                     legacy OpenFlow controllers that expect this behavior.

              •      The legacy_l3 option is only available via the user space
                     datapath.  The  OVS  kernel datapath does not support de‐
                     vices of type ARPHRD_IPGRE which is the  requirement  for
                     legacy_l3 type packets.

              •      If this option is ptap, the tunnel sends and receives any
                     kind of packet. Open vSwitch represents  packets  in  the
                     tunnel  using  the  packet_type  mechanism  introduced in
                     OpenFlow 1.5.

       options : seq: optional string, either true or false
              Optional. A 4-byte sequence number field for  GRE  tunnel  only.
              Default  is  disabled, set to true to enable. Sequence number is
              incremented by one on each outgoing packet.

     Tunnel Options: gre, geneve, and vxlan:

       gre, geneve, and vxlan interfaces support these options.

       options : csum: optional string, either true or false
              Optional. Compute  encapsulation  header  (either  GRE  or  UDP)
              checksums  on outgoing packets. Default is disabled, set to true
              to enable. Checksums present on incoming packets will  be  vali‐
              dated regardless of this setting.

              When  using  the  upstream  Linux  kernel module, computation of
              checksums for geneve and vxlan requires Linux kernel version 4.0
              or  higher.  gre  supports  checksums  for  all versions of Open
              vSwitch that support GRE. The out of tree kernel module distrib‐
              uted as part of OVS can compute all tunnel checksums on any ker‐
              nel version that it is compatible with.

     Tunnel Options: IPsec:

       Setting any of these options enables IPsec support for a given  tunnel.
       gre,  geneve,  vxlan, and stt interfaces support these options. See the
       IPsec section in the Open_vSwitch table for a description of each mode.

       options : psk: optional string
              In PSK mode only, the preshared secret to negotiate tunnel. This
              value must match on both tunnel ends.

       options : remote_cert: optional string
              In  self-signed  certificate  mode only, name of a PEM file con‐
              taining a certificate of the remote switch. The certificate must
              be  x.509 version 3 and with the string in common name (CN) also
              set in the subject alternative name (SAN).

       options : remote_name: optional string
              In CA-signed certificate mode only, common name (CN) of the  re‐
              mote certificate.

     Tunnel Options: erspan only:

       Only erspan interfaces support these options.

       options : erspan_idx: optional string
              20  bit  index/port  number associated with the ERSPAN traffic’s
              source port and direction (ingress/egress). This field is  plat‐
              form dependent.

       options : erspan_ver: optional string
              ERSPAN  version:  1  for  version 1 (type II) or 2 for version 2
              (type III).

       options : erspan_dir: optional string
              Specifies the ERSPAN v2  mirrored  traffic’s  direction.  1  for
              egress traffic, and 0 for ingress traffic.

       options : erspan_hwid: optional string
              ERSPAN  hardware ID is a 6-bit unique identifier of an ERSPAN v2
              engine within a system.

     Patch Options:

       These options apply only to patch ports, that is, interfaces whose type
       column  is patch. Patch ports are mainly a way to connect otherwise in‐
       dependent bridges to one another, similar to how one might plug an Eth‐
       ernet  cable  (a ``patch cable’’) into two physical switches to connect
       those switches. The effect of plugging a patch port into  two  switches
       is  conceptually  similar  to  that of plugging the two ends of a Linux
       veth device into those switches, but the implementation of patch  ports
       makes them much more efficient.

       Patch  ports  may connect two different bridges (the usual case) or the
       same bridge. In the latter case, take special care to avoid loops, e.g.
       by programming appropriate flows with OpenFlow. Patch ports do not work
       if its ends are attached to bridges on  different  datapaths,  e.g.  to
       connect bridges in system and netdev datapaths.

       The  following  command  creates and connects patch ports p0 and p1 and
       adds them to bridges br0 and br1, respectively:

       ovs-vsctl add-port br0 p0 -- set Interface p0 type=patch options:peer=p1 \
              -- add-port br1 p1 -- set Interface p1 type=patch options:peer=p0


       options : peer: optional string
              The name of the Interface for the other side of the  patch.  The
              named  Interface’s own peer option must specify this Interface’s
              name. That is, the two patch interfaces must have reversed  name
              and peer values.

     PMD (Poll Mode Driver) Options:

       Only PMD netdevs support these options.

       options : n_rxq: optional string, containing an integer, at least 1
              Specifies  the maximum number of rx queues to be created for PMD
              netdev. If not specified or specified to 0, one rx queue will be
              created by default. Not supported by DPDK vHost interfaces.

       options : dpdk-devargs: optional string
              Specifies  the PCI address associated with the port for physical
              devices, or the virtual driver to be used for the  port  when  a
              virtual PMD is intended to be used. For the latter, the argument
              string typically  takes  the  form  of  eth_driver_namex,  where
              driver_name  is  a valid virtual DPDK PMD driver name and x is a
              unique identifier of your choice for the given port.  Only  sup‐
              ported by the dpdk port type.

       other_config : pmd-rxq-affinity: optional string
              Specifies mapping of RX queues of this interface to CPU cores.

              Value should be set in the following form:

              other_config:pmd-rxq-affinity=rxq-affinity-list>gt;>gt;

              where

              •      gt; ::= NULL | gt;

              •      gt;  ::= gt; | gt; ,
                     gt;

              •      gt; ::= gt; : gt;

       options : vhost-server-path: optional string
              The value specifies the path to the  socket  associated  with  a
              vHost  User  client mode device that has been or will be created
              by QEMU. Only supported by dpdkvhostuserclient interfaces.

       options : dq-zero-copy: optional string, either true or false
              The value specifies whether or not to enable dequeue  zero  copy
              on  the given interface. Must be set before vhost-server-path is
              specified. Only supported by dpdkvhostuserclient interfaces. The
              feature is considered experimental.

       options  : n_rxq_desc: optional string, containing an integer, in range
       1 to 4,096
              Specifies the rx queue size (number  rx  descriptors)  for  dpdk
              ports.  The  value must be a power of 2, less than 4096 and sup‐
              ported by the hardware of the device being  configured.  If  not
              specified  or  an incorrect value is specified, 2048 rx descrip‐
              tors will be used by default.

       options : n_txq_desc: optional string, containing an integer, in  range
       1 to 4,096
              Specifies  the  tx  queue  size (number tx descriptors) for dpdk
              ports. The value must be a power of 2, less than 4096  and  sup‐
              ported  by  the  hardware of the device being configured. If not
              specified or an incorrect value is specified, 2048  tx  descrip‐
              tors will be used by default.

     EMC (Exact Match Cache) Configuration:

       These settings controls behaviour of EMC lookups/insertions for packets
       received from the interface.

       other_config : emc-enable: optional string, either true or false
              Specifies if Exact Match Cache (EMC) should be used  while  pro‐
              cessing   packets   received   from  this  interface.  If  true,
              other_config:emc-insert-inv-prob will have effect on this inter‐
              face.

              Defaults to true.

     MTU:

       The  MTU (maximum transmission unit) is the largest amount of data that
       can fit into a single Ethernet frame. The standard Ethernet MTU is 1500
       bytes.  Some physical media and many kinds of virtual interfaces can be
       configured with higher MTUs.

       A client may change an interface MTU by filling  in  mtu_request.  Open
       vSwitch then reports in mtu the currently configured value.

       mtu: optional integer
              The currently configured MTU for the interface.

              This column will be empty for an interface that does not have an
              MTU as, for example, some kinds of tunnels do not.

              Open vSwitch sets this column’s value, so other  clients  should
              treat it as read-only.

       mtu_request: optional integer, at least 1
              Requested  MTU  (Maximum Transmission Unit) for the interface. A
              client can fill this column to change the MTU of an interface.

              RFC 791 requires every internet module to be able to  forward  a
              datagram of 68 octets without further fragmentation. The maximum
              size of an IP packet is 65535 bytes.

              If this is not set and if the interface has internal type,  Open
              vSwitch  will  change  the MTU to match the minimum of the other
              interfaces in the bridge.

     Interface Status:

       Status information about interfaces attached to bridges, updated  every
       5 seconds. Not all interfaces have all of these properties; virtual in‐
       terfaces don’t have a link speed, for example.  Non-applicable  columns
       will have empty values.

       admin_state: optional string, either down or up
              The administrative state of the physical network link.

       link_state: optional string, either down or up
              The  observed  state of the physical network link. This is ordi‐
              narily the link’s carrier status. If the interface’s Port  is  a
              bond configured for miimon monitoring, it is instead the network
              link’s miimon status.

       link_resets: optional integer
              The number of times Open vSwitch has observed the link_state  of
              this Interface change.

       link_speed: optional integer
              The  negotiated speed of the physical network link. Valid values
              are positive integers greater than 0.

       duplex: optional string, either full or half
              The duplex mode of the physical network link.

       lacp_current: optional boolean
              Boolean value indicating LACP  status  for  this  interface.  If
              true, this interface has current LACP information about its LACP
              partner. This information may be used to monitor the  health  of
              interfaces  in a LACP enabled port. This column will be empty if
              LACP is not enabled.

       status: map of string-string pairs
              Key-value pairs that report port status. Supported status values
              are  type-dependent;  some  interfaces may not have a valid sta
              tus:driver_name, for example.

       status : driver_name: optional string
              The name of the device driver controlling the network adapter.

       status : driver_version: optional string
              The version string of the device driver controlling the  network
              adapter.

       status : firmware_version: optional string
              The  version string of the network adapter’s firmware, if avail‐
              able.

       status : source_ip: optional string
              The source IP address used for an  IPv4/IPv6  tunnel  end-point,
              such as gre.

       status : tunnel_egress_iface: optional string
              Egress  interface  for tunnels. Currently only relevant for tun‐
              nels on Linux systems, this column will show the name of the in‐
              terface  which  is  responsible for routing traffic destined for
              the configured options:remote_ip. This could be an internal  in‐
              terface such as a bridge port.

       status  :  tunnel_egress_iface_carrier: optional string, either down or
       up
              Whether carrier is detected on status:tunnel_egress_iface.

     dpdk:

       DPDK specific interface status options.

       status : port_no: optional string
              DPDK port ID.

       status : numa_id: optional string
              NUMA socket ID to which an Ethernet device is connected.

       status : min_rx_bufsize: optional string
              Minimum size of RX buffer.

       status : max_rx_pktlen: optional string
              Maximum configurable length of RX pkt.

       status : max_rx_queues: optional string
              Maximum number of RX queues.

       status : max_tx_queues: optional string
              Maximum number of TX queues.

       status : max_mac_addrs: optional string
              Maximum number of MAC addresses.

       status : max_hash_mac_addrs: optional string
              Maximum number of hash MAC addresses for MTA and UTA.

       status : max_vfs: optional string
              Maximum number of hash MAC addresses for MTA  and  UTA.  Maximum
              number of VFs.

       status : max_vmdq_pools: optional string
              Maximum number of VMDq pools.

       status : if_type: optional string
              Interface type ID according to IANA ifTYPE MIB definitions.

       status : if_descr: optional string
              Interface description string.

       status : pci-vendor_id: optional string
              Vendor ID of PCI device.

       status : pci-device_id: optional string
              Device ID of PCI device.

     Statistics:

       Key-value pairs that report interface statistics. The current implemen‐
       tation updates these counters periodically. The update period  is  con‐
       trolled  by  other_config:stats-update-interval in the Open_vSwitch ta‐
       ble. Future implementations may update them when an interface  is  cre‐
       ated, when they are queried (e.g. using an OVSDB select operation), and
       just before an interface is deleted due to virtual interface hot-unplug
       or  VM shutdown, and perhaps at other times, but not on any regular pe‐
       riodic basis.

       These are the same  statistics  reported  by  OpenFlow  in  its  struct
       ofp_port_stats  structure.  If  an  interface  does not support a given
       statistic, then that pair is omitted.

     Statistics: Successful transmit and receive counters:

       statistics : rx_packets: optional integer
              Number of received packets.

       statistics : rx_bytes: optional integer
              Number of received bytes.

       statistics : tx_packets: optional integer
              Number of transmitted packets.

       statistics : tx_bytes: optional integer
              Number of transmitted bytes.

     Statistics: Receive errors:

       statistics : rx_dropped: optional integer
              Number of packets dropped by RX.

       statistics : rx_frame_err: optional integer
              Number of frame alignment errors.

       statistics : rx_over_err: optional integer
              Number of packets with RX overrun.

       statistics : rx_crc_err: optional integer
              Number of CRC errors.

       statistics : rx_errors: optional integer
              Total number of receive errors, greater than or equal to the sum
              of the above.

     Statistics: Transmit errors:

       statistics : tx_dropped: optional integer
              Number of packets dropped by TX.

       statistics : collisions: optional integer
              Number of collisions.

       statistics : tx_errors: optional integer
              Total  number  of  transmit errors, greater than or equal to the
              sum of the above.

     Ingress Policing:

       These settings control ingress policing for packets  received  on  this
       interface. On a physical interface, this limits the rate at which traf‐
       fic is allowed into the system from the outside; on a virtual interface
       (one connected to a virtual machine), this limits the rate at which the
       VM is able to transmit.

       Policing is a simple form of quality-of-service that simply drops pack‐
       ets  received  in excess of the configured rate. Due to its simplicity,
       policing is usually less accurate and less effective  than  egress  QoS
       (which is configured using the QoS and Queue tables).

       Policing  is currently implemented on Linux and OVS with DPDK. Both im‐
       plementations use a simple ``token bucket’’ approach:

              •      The size of  the  bucket  corresponds  to  ingress_polic
                     ing_burst. Initially the bucket is full.

              •      Whenever a packet is received, its size (converted to to‐
                     kens) is compared to the number of  tokens  currently  in
                     the  bucket.  If the required number of tokens are avail‐
                     able, they are removed and the packet is forwarded.  Oth‐
                     erwise, the packet is dropped.

              •      Whenever  it is not full, the bucket is refilled with to‐
                     kens at the rate specified by ingress_policing_rate.

       Policing interacts badly with some network  protocols,  and  especially
       with fragmented IP packets. Suppose that there is enough network activ‐
       ity to keep the bucket nearly empty  all  the  time.  Then  this  token
       bucket  algorithm will forward a single packet every so often, with the
       period depending on packet size and on the configured rate. All of  the
       fragments  of an IP packets are normally transmitted back-to-back, as a
       group. In such a situation, therefore, only one of these fragments will
       be  forwarded and the rest will be dropped. IP does not provide any way
       for the intended recipient to ask for only the remaining fragments.  In
       such  a  case  there  are two likely possibilities for what will happen
       next: either all of the fragments will eventually be retransmitted  (as
       TCP  will do), in which case the same problem will recur, or the sender
       will not realize that its packet has been dropped and data will  simply
       be lost (as some UDP-based protocols will do). Either way, it is possi‐
       ble that no forward progress will ever occur.

       ingress_policing_rate: integer, at least 0
              Maximum rate for data received on this interface, in kbps.  Data
              received  faster  than  this  rate is dropped. Set to 0 (the de‐
              fault) to disable policing.

       ingress_policing_burst: integer, at least 0
              Maximum burst size for data received on this interface,  in  kb.
              The  default burst size if set to 0 is 8000 kbit. This value has
              no effect if ingress_policing_rate is 0.

              Specifying a larger burst size lets the algorithm be  more  for‐
              giving, which is important for protocols like TCP that react se‐
              verely to dropped packets. The burst size should be at least the
              size  of the interface’s MTU. Specifying a value that is numeri‐
              cally at least as large as 80%  of  ingress_policing_rate  helps
              TCP come closer to achieving the full rate.

     Bidirectional Forwarding Detection (BFD):

       BFD,  defined in RFC 5880 and RFC 5881, allows point-to-point detection
       of connectivity failures by occasional transmission of BFD control mes‐
       sages. Open vSwitch implements BFD to serve as a more popular and stan‐
       dards compliant alternative to CFM.

       BFD operates by regularly transmitting BFD control messages at  a  rate
       negotiated independently in each direction. Each endpoint specifies the
       rate at which it expects to receive control messages, and the  rate  at
       which  it  is willing to transmit them. By default, Open vSwitch uses a
       detection multiplier of three, meaning that an endpoint signals a  con‐
       nectivity  fault  if three consecutive BFD control messages fail to ar‐
       rive. In the case of a unidirectional connectivity  issue,  the  system
       not  receiving  BFD control messages signals the problem to its peer in
       the messages it transmits.

       The Open vSwitch implementation of BFD aims to comply  faithfully  with
       RFC 5880 requirements. Open vSwitch does not implement the optional Au‐
       thentication or ``Echo Mode’’ features.

     BFD Configuration:

       A controller sets up key-value pairs in the bfd column  to  enable  and
       configure BFD.

       bfd : enable: optional string, either true or false
              True to enable BFD on this Interface. If not specified, BFD will
              not be enabled by default.

       bfd : min_rx: optional string, containing an integer, at least 1
              The shortest interval, in milliseconds, at which this  BFD  ses‐
              sion offers to receive BFD control messages. The remote endpoint
              may choose to send messages at a slower rate. Defaults to 1000.

       bfd : min_tx: optional string, containing an integer, at least 1
              The shortest interval, in milliseconds, at which this  BFD  ses‐
              sion  is willing to transmit BFD control messages. Messages will
              actually be transmitted at a slower rate if the remote  endpoint
              is  not  willing to receive as quickly as specified. Defaults to
              100.

       bfd : decay_min_rx: optional string, containing an integer
              An alternate receive interval, in  milliseconds,  that  must  be
              greater than or equal to bfd:min_rx. The implementation switches
              from bfd:min_rx to bfd:decay_min_rx when there is no obvious in‐
              coming  data  traffic  at  the  interface, to reduce the CPU and
              bandwidth cost of monitoring an idle interface. This feature may
              be disabled by setting a value of 0. This feature is reset when‐
              ever bfd:decay_min_rx or bfd:min_rx changes.

       bfd : forwarding_if_rx: optional string, either true or false
              When true, traffic received on the Interface is used to indicate
              the  capability  of  packet  I/O.  BFD control packets are still
              transmitted and received. At least one BFD control  packet  must
              be  received  every  100 * bfd:min_rx amount of time. Otherwise,
              even if traffic are received, the bfd:forwarding will be false.

       bfd : cpath_down: optional string, either true or false
              Set to true to notify the remote endpoint  that  traffic  should
              not  be  forwarded  to  this system for some reason other than a
              connectivty failure on the interface being monitored. The  typi‐
              cal  underlying  reason  is ``concatenated path down,’’ that is,
              that connectivity beyond the local system is down.  Defaults  to
              false.

       bfd : check_tnl_key: optional string, either true or false
              Set to true to make BFD accept only control messages with a tun‐
              nel key of zero. By default, BFD accepts control  messages  with
              any tunnel key.

       bfd : bfd_local_src_mac: optional string
              Set  to an Ethernet address in the form xx:xx:xx:xx:xx:xx to set
              the MAC used as source for transmitted BFD packets. The  default
              is the mac address of the BFD enabled interface.

       bfd : bfd_local_dst_mac: optional string
              Set  to an Ethernet address in the form xx:xx:xx:xx:xx:xx to set
              the MAC used as destination for transmitted BFD packets. The de‐
              fault is 00:23:20:00:00:01.

       bfd : bfd_remote_dst_mac: optional string
              Set  to an Ethernet address in the form xx:xx:xx:xx:xx:xx to set
              the MAC used for checking the destination of received BFD  pack‐
              ets.  Packets with different destination MAC will not be consid‐
              ered as BFD packets. If not specified the  destination  MAC  ad‐
              dress of received BFD packets are not checked.

       bfd : bfd_src_ip: optional string
              Set  to an IPv4 address to set the IP address used as source for
              transmitted BFD packets. The default is 169.254.1.1.

       bfd : bfd_dst_ip: optional string
              Set to an IPv4 address to set the IP address used as destination
              for transmitted BFD packets. The default is 169.254.1.0.

       bfd : oam: optional string
              Some  tunnel  protocols  (such  as  Geneve) include a bit in the
              header to indicate that the encapsulated packet is an OAM frame.
              By  setting  this  to true, BFD packets will be marked as OAM if
              encapsulated in one of these tunnels.

       bfd : mult: optional string, containing an integer, in range 1 to 255
              The BFD detection multiplier, which defaults to 3.  An  endpoint
              signals  a connectivity fault if the given number of consecutive
              BFD control messages fail to arrive.

     BFD Status:

       The switch sets key-value pairs in the bfd_status column to report  the
       status  of BFD on this interface. When BFD is not enabled, with bfd:en
       able, the switch clears all key-value pairs from bfd_status.

       bfd_status : state: optional string, one of admin_down, down, init,  or
       up
              Reports  the  state of the BFD session. The BFD session is fully
              healthy and negotiated if UP.

       bfd_status : forwarding: optional string, either true or false
              Reports whether the BFD session believes this Interface  may  be
              used  to forward traffic. Typically this means the local session
              is signaling UP, and the remote system isn’t signaling a problem
              such as concatenated path down.

       bfd_status : diagnostic: optional string
              A  diagnostic  code specifying the local system’s reason for the
              last change in session state. The error messages are defined  in
              section 4.1 of [RFC 5880].

       bfd_status  :  remote_state:  optional string, one of admin_down, down,
       init, or up
              Reports the state of the remote endpoint’s BFD session.

       bfd_status : remote_diagnostic: optional string
              A diagnostic code specifying the remote system’s reason for  the
              last  change in session state. The error messages are defined in
              section 4.1 of [RFC 5880].

       bfd_status : flap_count: optional string,  containing  an  integer,  at
       least 0
              Counts  the number of bfd_status:forwarding flaps since start. A
              flap is considered as  a  change  of  the  bfd_status:forwarding
              value.

     Connectivity Fault Management:

       802.1ag  Connectivity  Fault Management (CFM) allows a group of Mainte‐
       nance Points (MPs) called a Maintenance Association (MA) to detect con‐
       nectivity  problems  with  each other. MPs within a MA should have com‐
       plete and exclusive interconnectivity. This is verified by occasionally
       broadcasting  Continuity Check Messages (CCMs) at a configurable trans‐
       mission interval.

       According to the 802.1ag specification, each Maintenance  Point  should
       be  configured  out-of-band with a list of Remote Maintenance Points it
       should have connectivity to. Open vSwitch differs from  the  specifica‐
       tion  in  this area. It simply assumes the link is faulted if no Remote
       Maintenance Points are reachable, and considers it not  faulted  other‐
       wise.

       When operating over tunnels which have no in_key, or an in_key of flow.
       CFM will only accept CCMs with a tunnel key of zero.

       cfm_mpid: optional integer
              A Maintenance Point ID (MPID) uniquely identifies each  endpoint
              within  a  Maintenance Association. The MPID is used to identify
              this endpoint to other Maintenance Points in the MA. Each end of
              a  link  being  monitored  should have a different MPID. Must be
              configured to enable CFM on this Interface.

              According to the 802.1ag specification, MPIDs can only range be‐
              tween   [1,   8191].  However,  extended  mode  (see  other_con
              fig:cfm_extended) supports eight byte MPIDs.

       cfm_flap_count: optional integer
              Counts the number of cfm fault flapps since boot. A flap is con‐
              sidered to be a change of the cfm_fault value.

       cfm_fault: optional boolean
              Indicates  a connectivity fault triggered by an inability to re‐
              ceive heartbeats from any remote endpoint. When a fault is trig‐
              gered  on  Interfaces  participating in bonds, they will be dis‐
              abled.

              Faults can be triggered for several  reasons.  Most  importantly
              they are triggered when no CCMs are received for a period of 3.5
              times the transmission interval. Faults are also triggered  when
              any CCMs indicate that a Remote Maintenance Point is not receiv‐
              ing CCMs but able to send them. Finally, a fault is triggered if
              a  CCM is received which indicates unexpected configuration. No‐
              tably, this case arises when a CCM is received which  advertises
              the local MPID.

       cfm_fault_status : recv: none
              Indicates  a  CFM  fault was triggered due to a lack of CCMs re‐
              ceived on the Interface.

       cfm_fault_status : rdi: none
              Indicates a CFM fault was triggered due to the  reception  of  a
              CCM with the RDI bit flagged. Endpoints set the RDI bit in their
              CCMs when they are not receiving CCMs themselves. This typically
              indicates a unidirectional connectivity failure.

       cfm_fault_status : maid: none
              Indicates  a  CFM  fault was triggered due to the reception of a
              CCM with a MAID other than the one Open vSwitch uses. CFM broad‐
              casts  are  tagged  with an identification number in addition to
              the MPID called the MAID. Open vSwitch only  supports  receiving
              CCM broadcasts tagged with the MAID it uses internally.

       cfm_fault_status : loopback: none
              Indicates  a  CFM  fault was triggered due to the reception of a
              CCM advertising the same MPID configured in the cfm_mpid  column
              of this Interface. This may indicate a loop in the network.

       cfm_fault_status : overflow: none
              Indicates  a  CFM fault was triggered because the CFM module re‐
              ceived CCMs from more remote endpoints than it  can  keep  track
              of.

       cfm_fault_status : override: none
              Indicates a CFM fault was manually triggered by an administrator
              using an ovs-appctl command.

       cfm_fault_status : interval: none
              Indicates a CFM fault was triggered due to the  reception  of  a
              CCM frame having an invalid interval.

       cfm_remote_opstate: optional string, either down or up
              When  in  extended  mode, indicates the operational state of the
              remote endpoint as either up or down.  See  other_config:cfm_op
              state.

       cfm_health: optional integer, in range 0 to 100
              Indicates  the  health  of  the interface as a percentage of CCM
              frames received over 21 other_config:cfm_intervals.  The  health
              of  an  interface  is undefined if it is communicating with more
              than one cfm_remote_mpids. It reduces if healthy heartbeats  are
              not  received  at  the  expected rate, and gradually improves as
              healthy heartbeats are received at the desired  rate.  Every  21
              other_config:cfm_intervals,  the  health of the interface is re‐
              freshed.

              As mentioned above, the faults can be triggered for several rea‐
              sons.  The  link  health will deteriorate even if heartbeats are
              received but they are reported to  be  unhealthy.  An  unhealthy
              heartbeat  in  this context is a heartbeat for which either some
              fault is set or is out of sequence. The interface health can  be
              100 only on receiving healthy heartbeats at the desired rate.

       cfm_remote_mpids: set of integers
              When  CFM is properly configured, Open vSwitch will occasionally
              receive CCM broadcasts. These broadcasts contain the MPID of the
              sending Maintenance Point. The list of MPIDs from which this In
              terface is receiving broadcasts from is regularly collected  and
              written to this column.

       other_config : cfm_interval: optional string, containing an integer
              The  interval,  in  milliseconds,  between  transmissions of CFM
              heartbeats. Three missed heartbeat receptions indicate a connec‐
              tivity fault.

              In  standard  operation  only  intervals  of  3, 10, 100, 1,000,
              10,000, 60,000, or 600,000 ms are supported. Other  values  will
              be  rounded down to the nearest value on the list. Extended mode
              (see other_config:cfm_extended)  supports  any  interval  up  to
              65,535 ms. In either mode, the default is 1000 ms.

              We do not recommend using intervals less than 100 ms.

       other_config : cfm_extended: optional string, either true or false
              When true, the CFM module operates in extended mode. This causes
              it to use a nonstandard destination address to avoid conflicting
              with compliant implementations which may be running concurrently
              on the network. Furthermore, extended mode increases  the  accu‐
              racy  of  the  cfm_interval  configuration parameter by breaking
              wire compatibility with 802.1ag compliant  implementations.  And
              extended mode allows eight byte MPIDs. Defaults to false.

       other_config : cfm_demand: optional string, either true or false
              When true, and other_config:cfm_extended is true, the CFM module
              operates in demand mode. When in demand mode,  traffic  received
              on  the  Interface  is used to indicate liveness. CCMs are still
              transmitted and received. At least one CCM must be received  ev‐
              ery  100  * other_config:cfm_interval amount of time. Otherwise,
              even if traffic are received, the CFM module will raise the con‐
              nectivity fault.

              Demand mode has a couple of caveats:

              •      To  ensure that ovs-vswitchd has enough time to pull sta‐
                     tistics from the datapath, the fault  detection  interval
                     is set to 3.5 * MAX(other_config:cfm_interval, 500) ms.

              •      To  avoid  ambiguity,  demand  mode  disables itself when
                     there are multiple remote maintenance points.

              •      If the Interface is heavily  congested,  CCMs  containing
                     the  other_config:cfm_opstate status may be dropped caus‐
                     ing changes in the operational state to be delayed. Simi‐
                     larly,  if  CCMs containing the RDI bit are not received,
                     unidirectional link failures may not be detected.

       other_config : cfm_opstate: optional string, either down or up
              When down, the CFM module marks all CCMs it generates as  opera‐
              tionally  down  without  triggering  a fault. This allows remote
              maintenance points to choose not to forward traffic to  the  In
              terface  on which this CFM module is running. Currently, in Open
              vSwitch, the opdown bit of CCMs affects Interfaces participating
              in  bonds,  and  the bundle OpenFlow action. This setting is ig‐
              nored when CFM is not in extended mode. Defaults to up.

       other_config : cfm_ccm_vlan: optional string, containing an integer, in
       range 1 to 4,095
              When  set,  the  CFM module will apply a VLAN tag to all CCMs it
              generates with the given value. May  be  the  string  random  in
              which  case  each  CCM  will be tagged with a different randomly
              generated VLAN.

       other_config : cfm_ccm_pcp: optional string, containing an integer,  in
       range 1 to 7
              When  set,  the  CFM module will apply a VLAN tag to all CCMs it
              generates with the given PCP value, the VLAN ID of  the  tag  is
              governed   by   the   value   of  other_config:cfm_ccm_vlan.  If
              other_config:cfm_ccm_vlan is unset, a VLAN ID of zero is used.

     Bonding Configuration:

       other_config : lacp-port-id: optional string, containing an integer, in
       range 1 to 65,535
              The  LACP  port  ID of this Interface. Port IDs are used in LACP
              negotiations to identify individual  ports  participating  in  a
              bond.

       other_config : lacp-port-priority: optional string, containing an inte‐
       ger, in range 1 to 65,535
              The LACP port priority of this Interface. In  LACP  negotiations
              Interfaces  with  numerically lower priorities are preferred for
              aggregation.

       other_config : lacp-aggregation-key: optional string, containing an in‐
       teger, in range 1 to 65,535
              The LACP aggregation key of this Interface. Interfaces with dif‐
              ferent aggregation keys may not be active within a given Port at
              the same time.

     Virtual Machine Identifiers:

       These  key-value  pairs  specifically apply to an interface that repre‐
       sents a virtual Ethernet interface  connected  to  a  virtual  machine.
       These  key-value  pairs should not be present for other types of inter‐
       faces. Keys whose names end in -uuid have values that uniquely identify
       the entity in question. For a Citrix XenServer hypervisor, these values
       are UUIDs in RFC 4122 format. Other hypervisors may use other formats.

       external_ids : attached-mac: optional string
              The MAC address programmed into  the  ``virtual  hardware’’  for
              this  interface,  in  the  form  xx:xx:xx:xx:xx:xx.  For  Citrix
              XenServer, this is the value of the MAC field in the VIF  record
              for this interface.

       external_ids : iface-id: optional string
              A system-unique identifier for the interface. On XenServer, this
              will commonly be the same as external_ids:xs-vif-uuid.

       external_ids : iface-status: optional string, either active or inactive
              Hypervisors may sometimes have more than one  interface  associ‐
              ated  with  a  given external_ids:iface-id, only one of which is
              actually in use at a given time. For example,  in  some  circum‐
              stances XenServer has both a ``tap’’ and a ``vif’’ interface for
              a single external_ids:iface-id, but only uses one of them  at  a
              time. A hypervisor that behaves this way must mark the currently
              in use interface active and the others  inactive.  A  hypervisor
              that  never  has  more  than  one  interface  for a given exter
              nal_ids:iface-id may mark that interface active or  omit  exter
              nal_ids:iface-status entirely.

              During  VM  migration, a given external_ids:iface-id might tran‐
              siently be marked active on two different hypervisors. That  is,
              active  means  that this external_ids:iface-id is the active in‐
              stance within a single hypervisor, not in a broader scope. There
              is  one exception: some hypervisors support ``migration’’ from a
              given hypervisor to itself (most often for test purposes).  Dur‐
              ing  such  a  ``migration,’’  two  instances  of a single exter
              nal_ids:iface-id might both be briefly marked active on a single
              hypervisor.

       external_ids : xs-vif-uuid: optional string
              The virtual interface associated with this interface.

       external_ids : xs-network-uuid: optional string
              The virtual network to which this interface is attached.

       external_ids : vm-id: optional string
              The  VM to which this interface belongs. On XenServer, this will
              be the same as external_ids:xs-vm-uuid.

       external_ids : xs-vm-uuid: optional string
              The VM to which this interface belongs.

     Auto Attach Configuration:

       Auto Attach configuration for a particular interface.

       lldp : enable: optional string, either true or false
              True to enable LLDP on this Interface. If  not  specified,  LLDP
              will be disabled by default.

     Flow control Configuration:

       Ethernet flow control defined in IEEE 802.1Qbb provides link level flow
       control using MAC pause frames. Implemented only  for  interfaces  with
       type dpdk.

       options : rx-flow-ctrl: optional string, either true or false
              Set  to true to enable Rx flow control on physical ports. By de‐
              fault, Rx flow control is disabled.

       options : tx-flow-ctrl: optional string, either true or false
              Set to true to enable Tx flow control on physical ports. By  de‐
              fault, Tx flow control is disabled.

       options : flow-ctrl-autoneg: optional string, either true or false
              Set  to true to enable flow control auto negotiation on physical
              ports. By default, auto-neg is disabled.

     Link State Change detection mode:

       options : dpdk-lsc-interrupt: optional string, either true or false
              Set this value to true to  configure  interrupt  mode  for  Link
              State  Change  (LSC) detection instead of poll mode for the DPDK
              interface.

              If this value is not set, poll mode is configured.

              This parameter has an effect only on netdev dpdk interfaces.

     Common Columns:

       The overall purpose of these columns is described under Common  Columns
       at the beginning of this document.

       other_config: map of string-string pairs

       external_ids: map of string-string pairs

Flow_Table TABLE
       Configuration for a particular OpenFlow table.

   Summary:
       name                          optional string
       Eviction Policy:
         flow_limit                  optional integer, at least 0
         overflow_policy             optional string, either evict or refuse
         groups                      set of strings
       Classifier Optimization:
         prefixes                    set of up to 3 strings
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       name: optional string
              The  table’s  name. Set this column to change the name that con‐
              trollers will receive when they request table  statistics,  e.g.
              ovs-ofctl dump-tables. The name does not affect switch behavior.

     Eviction Policy:

       Open  vSwitch  supports  limiting  the  number of flows that may be in‐
       stalled in a flow table, via the flow_limit column. When adding a  flow
       would  exceed this limit, by default Open vSwitch reports an error, but
       there are  two  ways  to  configure  Open  vSwitch  to  instead  delete
       (``evict’’) a flow to make room for the new one:

              •      Set the overflow_policy column to evict.

              •      Send  an  OpenFlow  1.4+  ``table mod request’’ to enable
                     eviction for the flow table (e.g. ovs-ofctl -O OpenFlow14
                     mod-table  br0 0 evict to enable eviction on flow table 0
                     of bridge br0).

       When a flow must be evicted due to overflow, the flow to evict is  cho‐
       sen through an approximation of the following algorithm. This algorithm
       is used regardless of how eviction was enabled:

              1.  Divide the flows in the table into groups based on the  val‐
                  ues  of the fields or subfields specified in the groups col‐
                  umn, so that all of the flows in a given group have the same
                  values  for those fields. If a flow does not specify a given
                  field, that field’s value is treated  as  0.  If  groups  is
                  empty,  then  all of the flows in the flow table are treated
                  as a single group.

              2.  Consider the flows in the largest group, that is, the  group
                  that  contains  the greatest number of flows. If two or more
                  groups all have the same largest number of  flows,  consider
                  the flows in all of those groups.

              3.  If  the  flows under consideration have different importance
                  values, eliminate from consideration any flows except  those
                  with  the lowest importance. (``Importance,’’ a 16-bit inte‐
                  ger value attached to each flow, was introduced in  OpenFlow
                  1.4.  Flows  inserted with older versions of OpenFlow always
                  have an importance of 0.)

              4.  Among the flows under consideration, choose  the  flow  that
                  expires soonest for eviction.

       The  eviction process only considers flows that have an idle timeout or
       a hard timeout. That is, eviction never deletes permanent flows.  (Per‐
       manent flows do count against flow_limit.)

       flow_limit: optional integer, at least 0
              If  set, limits the number of flows that may be added to the ta‐
              ble. Open vSwitch may limit the number of flows in a  table  for
              other  reasons, e.g. due to hardware limitations or for resource
              availability or performance reasons.

       overflow_policy: optional string, either evict or refuse
              Controls the switch’s behavior when an OpenFlow flow table modi‐
              fication  request  would  add flows in excess of flow_limit. The
              supported values are:

              refuse Refuse to add the flow or flows. This is also the default
                     policy when overflow_policy is unset.

              evict  Delete a flow chosen according to the algorithm described
                     above.

       groups: set of strings
              When overflow_policy is evict, this controls how flows are  cho‐
              sen  for  eviction  when  the  flow table would otherwise exceed
              flow_limit flows. Its value is a  set  of  NXM  fields  or  sub-
              fields,  each  of  which  takes  one  of  the  forms  field[] or
              field[start..end], e.g. NXM_OF_IN_PORT[]. Please see meta-flow.h
              for a complete list of NXM field names.

              Open  vSwitch  ignores  any  invalid or unknown field specifica‐
              tions.

              When eviction is not enabled, via overflow_policy or an OpenFlow
              1.4+ ``table mod,’’ this column has no effect.

     Classifier Optimization:

       prefixes: set of up to 3 strings
              This  string  set  specifies which fields should be used for ad‐
              dress prefix tracking. Prefix tracking allows the classifier  to
              skip  rules  with  longer  than necessary prefixes, resulting in
              better wildcarding for datapath flows.

              Prefix tracking may be beneficial when  a  flow  table  contains
              matches  on IP address fields with different prefix lengths. For
              example, when a flow table contains IP address matches  on  both
              full  addresses  and  proper  prefixes, the full address matches
              will typically cause the datapath flow to un-wildcard the  whole
              address field (depending on flow entry priorities). In this case
              each  packet  with  a  different  address  gets  handed  to  the
              userspace  for  flow  processing  and generates its own datapath
              flow. With prefix tracking enabled  for  the  address  field  in
              question  packets with addresses matching shorter prefixes would
              generate datapath flows where the irrelevant  address  bits  are
              wildcarded,  allowing  the  same datapath flow to handle all the
              packets within  the  prefix  in  question.  In  this  case  many
              userspace upcalls can be avoided and the overall performance can
              be better.

              This is a performance optimization only, so packets will receive
              the same treatment with or without prefix tracking.

              The    supported   fields   are:   tun_id,   tun_src,   tun_dst,
              tun_ipv6_src, tun_ipv6_dst, nw_src, nw_dst  (or  aliases  ip_src
              and  ip_dst),  ipv6_src,  and  ipv6_dst. (Using this feature for
              tun_id would only make sense  if  the  tunnel  IDs  have  prefix
              structure similar to IP addresses.)

              By default, the prefixes=ip_dst,ip_src are used on each flow ta‐
              ble. This instructs the flow classifier to track the IP destina‐
              tion  and  source  addresses  used by the rules in this specific
              flow table.

              The keyword none is recognized as an explicit  override  of  the
              default values, causing no prefix fields to be tracked.

              To set the prefix fields, the flow table record needs to exist:

              ovs-vsctl  set  Bridge  br0 flow_tables:0=@N1 -- --id=@N1 create
              Flow_Table name=table0
                     Creates a flow table record for the OpenFlow table number
                     0.

              ovs-vsctl set Flow_Table table0 prefixes=ip_dst,ip_src
                     Enables prefix tracking for IP source and destination ad‐
                     dress fields.

              There is a maximum number of fields that can be enabled for  any
              one flow table. Currently this limit is 3.

     Common Columns:

       The  overall purpose of these columns is described under Common Columns
       at the beginning of this document.

       external_ids: map of string-string pairs

QoS TABLE
       Quality of Service (QoS) configuration for each  Port  that  references
       it.

   Summary:
       type                          string
       queues                        map  of integer-Queue pairs, key in range
                                     0 to 4,294,967,295
       Configuration for linux-htb and linux-hfsc:
         other_config : max-rate     optional string, containing an integer
       Configuration for egress-policer QoS:
         other_config : cir          optional string, containing an integer
         other_config : cbs          optional string, containing an integer
       Configuration for linux-sfq:
         other_config : perturb      optional string, containing an integer
         other_config : quantum      optional string, containing an integer
       Common Columns:
         other_config                map of string-string pairs
         external_ids                map of string-string pairs

   Details:
       type: string
              The type of QoS to implement. The currently  defined  types  are
              listed below:

              linux-htb
                     Linux  ``hierarchy  token  bucket’’  classifier.  See tc-
                     htb(8) (also  at  http://linux.die.net/man/8/tc-htb)  and
                     the  HTB  manual (http://luxik.cdi.cz/~devik/qos/htb/man
                     ual/userg.htm) for information  on  how  this  classifier
                     works and how to configure it.

              linux-hfsc
                     Linux  "Hierarchical  Fair Service Curve" classifier. See
                     http://linux-ip.net/articles/hfsc.en/ for information  on
                     how this classifier works.

              linux-sfq
                     Linux  ``Stochastic  Fairness  Queueing’’ classifier. See
                     tc-sfq(8) (also at http://linux.die.net/man/8/tc-sfq) for
                     information on how this classifier works.

              linux-codel
                     Linux  ``Controlled  Delay’’  classifier. See tc-codel(8)
                     (also                                                  at
                     http://man7.org/linux/man-pages/man8/tc-codel.8.html) for
                     information on how this classifier works.

              linux-fq_codel
                     Linux ``Fair Queuing with Controlled Delay’’  classifier.
                     See           tc-fq_codel(8)           (also           at
                     http://man7.org/linux/man-pages/man8/tc-fq_codel.8.html)
                     for information on how this classifier works.

              linux-noop
                     Linux  ``No operation.’’ By default, Open vSwitch manages
                     quality of service on all of its configured  ports.  This
                     can  be  helpful,  but sometimes administrators prefer to
                     use other software to manage QoS. This type prevents Open
                     vSwitch from changing the QoS configuration for a port.

              egress-policer
                     A  DPDK egress policer algorithm using the DPDK rte_meter
                     library. The rte_meter library provides an implementation
                     which  allows  the  metering and policing of traffic. The
                     implementation in OVS essentially creates a single  token
                     bucket  used  to  police traffic. It should be noted that
                     when the rte_meter is configured as  part  of  QoS  there
                     will  be  a  performance overhead as the rte_meter itself
                     will consume CPU cycles in order to police traffic. These
                     CPU cycles ordinarily are used for packet proccessing. As
                     such the drop in performance will be noticed in terms  of
                     overall aggregate traffic throughput.

       queues: map of integer-Queue pairs, key in range 0 to 4,294,967,295
              A  map  from queue numbers to Queue records. The supported range
              of queue numbers depend on type. The queue numbers are the  same
              as  the  queue_id  used in OpenFlow in struct ofp_action_enqueue
              and other structures.

              Queue 0 is the ``default queue.’’ It is used by OpenFlow  output
              actions  when no specific queue has been set. When no configura‐
              tion for queue 0 is present, it is automatically  configured  as
              if  a  Queue record with empty dscp and other_config columns had
              been specified. (Before version 1.6, Open  vSwitch  would  leave
              queue  0  unconfigured  in  this  case. With some queuing disci‐
              plines, this  dropped  all  packets  destined  for  the  default
              queue.)

     Configuration for linux-htb and linux-hfsc:

       The  linux-htb  and  linux-hfsc classes support the following key-value
       pair:

       other_config : max-rate: optional string, containing an integer
              Maximum rate shared by all queued traffic, in  bit/s.  Optional.
              If  not  specified,  for physical interfaces, the default is the
              link rate. For other interfaces or if the link  rate  cannot  be
              determined, the default is currently 100 Mbps.

     Configuration for egress-policer QoS:

       QoS  type  egress-policer  provides  egress policing for userspace port
       types with DPDK. It has the following key-value pairs defined.

       other_config : cir: optional string, containing an integer
              The Committed Information Rate (CIR) is measured in bytes of  IP
              packets per second, i.e. it includes the IP header, but not link
              specific (e.g. Ethernet) headers. This represents the bytes  per
              second  rate  at which the token bucket will be updated. The cir
              value is calculated by (pps x packet data size). For example as‐
              suming  a  user  wishes  to limit a stream consisting of 64 byte
              packets to 1 million packets per second the CIR would be set  to
              to  to 46000000. This value can be broken into ’1,000,000 x 46’.
              Where 1,000,000 is the policing rate for the number  of  packets
              per  second  and 46 represents the size of the packet data for a
              64 byte ip packet.

       other_config : cbs: optional string, containing an integer
              The Committed Burst Size (CBS) is measured in bytes  and  repre‐
              sents  a  token bucket. At a minimum this value should be be set
              to the expected largest size packet in the  traffic  stream.  In
              practice  larger  values may be used to increase the size of the
              token bucket. If a packet can be transmitted then the  cbs  will
              be  decremented  by the number of bytes/tokens of the packet. If
              there are not enough tokens in the cbs bucket the packet will be
              dropped.

     Configuration for linux-sfq:

       The linux-sfq QoS supports the following key-value pairs:

       other_config : perturb: optional string, containing an integer
              Number  of  seconds between consecutive perturbations in hashing
              algorithm. Different flows can end up in the  same  hash  bucket
              causing  unfairness.  Perturbation’s  goal is to remove possible
              unfairness. The default and recommended value is 10. Too  low  a
              value  is discouraged because each perturbation can cause packet
              reordering.

       other_config : quantum: optional string, containing an integer
              Number of bytes linux-sfq QoS can dequeue in one turn in  round-
              robin  from one flow. The default and recommended value is equal
              to interface’s MTU.

     Common Columns:

       The overall purpose of these columns is described under Common  Columns
       at the beginning of this document.

       other_config: map of string-string pairs

       external_ids: map of string-string pairs

Queue TABLE
       A configuration for a port output queue, used in configuring Quality of
       Service (QoS) features. May be referenced by queues column in  QoS  ta‐
       ble.

   Summary:
       dscp                          optional integer, in range 0 to 63
       Configuration for linux-htb QoS:
         other_config : min-rate     optional  string,  containing an integer,
                                     at least 1
         other_config : max-rate     optional string, containing  an  integer,
                                     at least 1
         other_config : burst        optional  string,  containing an integer,
                                     at least 1
         other_config : priority     optional string, containing  an  integer,
                                     in range 0 to 4,294,967,295
       Configuration for linux-hfsc QoS:
         other_config : min-rate     optional  string,  containing an integer,
                                     at least 1
         other_config : max-rate     optional string, containing  an  integer,
                                     at least 1
       Common Columns:
         other_config                map of string-string pairs
         external_ids                map of string-string pairs

   Details:
       dscp: optional integer, in range 0 to 63
              If  set, Open vSwitch will mark all traffic egressing this Queue
              with the given DSCP bits. Traffic egressing the default Queue is
              only  marked  if  it was explicitly selected as the Queue at the
              time the packet was output. If unset, the DSCP bits  of  traffic
              egressing this Queue will remain unchanged.

     Configuration for linux-htb QoS:

       QoS  type  linux-htb may use queue_ids less than 61440. It has the fol‐
       lowing key-value pairs defined.

       other_config : min-rate: optional string,  containing  an  integer,  at
       least 1
              Minimum guaranteed bandwidth, in bit/s.

       other_config  :  max-rate:  optional  string, containing an integer, at
       least 1
              Maximum allowed bandwidth, in bit/s. Optional. If specified, the
              queue’s  rate will not be allowed to exceed the specified value,
              even if excess bandwidth is available. If unspecified,  defaults
              to no limit.

       other_config  : burst: optional string, containing an integer, at least
       1
              Burst size, in bits. This is the maximum amount  of  ``credits’’
              that  a queue can accumulate while it is idle. Optional. Details
              of the linux-htb implementation require a minimum burst size, so
              a too-small burst will be silently ignored.

       other_config  :  priority:  optional  string, containing an integer, in
       range 0 to 4,294,967,295
              A queue with a smaller priority  will  receive  all  the  excess
              bandwidth that it can use before a queue with a larger value re‐
              ceives any. Specific priority values are unimportant; only rela‐
              tive ordering matters. Defaults to 0 if unspecified.

     Configuration for linux-hfsc QoS:

       QoS  type linux-hfsc may use queue_ids less than 61440. It has the fol‐
       lowing key-value pairs defined.

       other_config : min-rate: optional string,  containing  an  integer,  at
       least 1
              Minimum guaranteed bandwidth, in bit/s.

       other_config  :  max-rate:  optional  string, containing an integer, at
       least 1
              Maximum allowed bandwidth, in bit/s. Optional. If specified, the
              queue’s  rate will not be allowed to exceed the specified value,
              even if excess bandwidth is available. If unspecified,  defaults
              to no limit.

     Common Columns:

       The  overall purpose of these columns is described under Common Columns
       at the beginning of this document.

       other_config: map of string-string pairs

       external_ids: map of string-string pairs

Mirror TABLE
       A port mirror within a Bridge.

       A port mirror configures a bridge to send selected  frames  to  special
       ``mirrored’’ ports, in addition to their normal destinations. Mirroring
       traffic may also be referred to as SPAN or RSPAN, depending on how  the
       mirrored traffic is sent.

       When  a  packet  enters an Open vSwitch bridge, it becomes eligible for
       mirroring based on its ingress port and VLAN.  As  the  packet  travels
       through  the  flow tables, each time it is output to a port, it becomes
       eligible for mirroring based on the  egress  port  and  VLAN.  In  Open
       vSwitch  2.5  and later, mirroring occurs just after a packet first be‐
       comes eligible, using the packet as it exists at that  point;  in  Open
       vSwitch  2.4 and earlier, mirroring occurs only after a packet has tra‐
       versed all the flow tables, using the original packet as it entered the
       bridge.  This  makes a difference only when the flow table modifies the
       packet: in Open vSwitch 2.4, the modifications  are  never  visible  to
       mirrors,  whereas  in Open vSwitch 2.5 and later modifications made be‐
       fore the first output that makes it eligible for mirroring to a partic‐
       ular destination are visible.

       A packet that enters an Open vSwitch bridge is mirrored to a particular
       destination only once, even if it is eligible for multiple reasons. For
       example,  a  packet  would be mirrored to a particular output_port only
       once, even if it  is  selected  for  mirroring  to  that  port  by  se
       lect_dst_port  and  select_src_port  in  the  same  or different Mirror
       records.

   Summary:
       name                          string
       Selecting Packets for Mirroring:
         select_all                  boolean
         select_dst_port             set of weak reference to Ports
         select_src_port             set of weak reference to Ports
         select_vlan                 set of up to 4,096 integers, in  range  0
                                     to 4,095
       Mirroring Destination Configuration:
         output_port                 optional weak reference to Port
         output_vlan                 optional integer, in range 1 to 4,095
         snaplen                     optional integer, in range 14 to 65,535
       Statistics: Mirror counters:
         statistics : tx_packets     optional integer
         statistics : tx_bytes       optional integer
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       name: string
              Arbitrary identifier for the Mirror.

     Selecting Packets for Mirroring:

       To  be  selected  for mirroring, a given packet must enter or leave the
       bridge through a selected port and it must also be in one  of  the  se‐
       lected VLANs.

       select_all: boolean
              If  true,  every packet arriving or departing on any port is se‐
              lected for mirroring.

       select_dst_port: set of weak reference to Ports
              Ports on which departing packets are selected for mirroring.

       select_src_port: set of weak reference to Ports
              Ports on which arriving packets are selected for mirroring.

       select_vlan: set of up to 4,096 integers, in range 0 to 4,095
              VLANs on which packets are selected for mirroring. An empty  set
              selects packets on all VLANs.

     Mirroring Destination Configuration:

       These  columns  are  mutually  exclusive.  Exactly  one of them must be
       nonempty.

       output_port: optional weak reference to Port
              Output port for selected packets, if nonempty.

              Specifying a port for mirror output reserves  that  port  exclu‐
              sively  for  mirroring.  No frames other than those selected for
              mirroring via this column will be forwarded to the port, and any
              frames received on the port will be discarded.

              The  output  port  may  be  any  kind  of port supported by Open
              vSwitch. It may be, for  example,  a  physical  port  (sometimes
              called SPAN) or a GRE tunnel.

       output_vlan: optional integer, in range 1 to 4,095
              Output VLAN for selected packets, if nonempty.

              The frames will be sent out all ports that trunk output_vlan, as
              well as any ports with implicit VLAN output_vlan.  When  a  mir‐
              rored  frame is sent out a trunk port, the frame’s VLAN tag will
              be set to output_vlan, replacing any existing tag;  when  it  is
              sent  out  an  implicit VLAN port, the frame will not be tagged.
              This type of mirroring is sometimes called RSPAN.

              See the documentation for other_config:forward-bpdu in  the  In
              terface table for a list of destination MAC addresses which will
              not be mirrored to a VLAN to avoid confusing switches  that  in‐
              terpret the protocols that they represent.

              Please note: Mirroring to a VLAN can disrupt a network that con‐
              tains unmanaged switches. Consider an unmanaged physical  switch
              with  two  ports:  port 1, connected to an end host, and port 2,
              connected to an Open vSwitch configured to mirror received pack‐
              ets  into  VLAN 123 on port 2. Suppose that the end host sends a
              packet on port 1 that the physical switch forwards  to  port  2.
              The  Open  vSwitch  forwards  this packet to its destination and
              then reflects it back on port 2  in  VLAN  123.  This  reflected
              packet  causes  the unmanaged physical switch to replace the MAC
              learning table entry, which correctly pointed to  port  1,  with
              one  that  incorrectly points to port 2. Afterward, the physical
              switch will direct packets destined for the end host to the Open
              vSwitch  on  port  2, instead of to the end host on port 1, dis‐
              rupting connectivity. If mirroring to a VLAN is desired in  this
              scenario,  then the physical switch must be replaced by one that
              learns Ethernet addresses on  a  per-VLAN  basis.  In  addition,
              learning  should  be  disabled  on  the VLAN containing mirrored
              traffic. If this is not done  then  intermediate  switches  will
              learn  the  MAC address of each end host from the mirrored traf‐
              fic. If packets being sent to that end host are  also  mirrored,
              then  they will be dropped since the switch will attempt to send
              them out the input port. Disabling learning for  the  VLAN  will
              cause the switch to correctly send the packet out all ports con‐
              figured for that VLAN. If Open vSwitch is being used as  an  in‐
              termediate  switch,  learning can be disabled by adding the mir‐
              rored VLAN to flood_vlans in the appropriate Bridge table or ta‐
              bles.

              Mirroring  to a GRE tunnel has fewer caveats than mirroring to a
              VLAN and should generally be preferred.

       snaplen: optional integer, in range 14 to 65,535
              Maximum per-packet number of bytes to mirror.

              A mirrored packet with size larger than snaplen  will  be  trun‐
              cated  in datapath to snaplen bytes before sending to the mirror
              output port. If omitted, packets are not truncated.

     Statistics: Mirror counters:

       Key-value pairs that report mirror statistics.  The  update  period  is
       controlled  by  other_config:stats-update-interval  in the Open_vSwitch
       table.

       statistics : tx_packets: optional integer
              Number of packets transmitted through this mirror.

       statistics : tx_bytes: optional integer
              Number of bytes transmitted through this mirror.

     Common Columns:

       The overall purpose of these columns is described under Common  Columns
       at the beginning of this document.

       external_ids: map of string-string pairs

Controller TABLE
       An OpenFlow controller.

       Open vSwitch supports two kinds of OpenFlow controllers:

              Primary controllers
                     This is the kind of controller envisioned by the OpenFlow
                     1.0 specification. Usually, a primary  controller  imple‐
                     ments  a  network policy by taking charge of the switch’s
                     flow table.

                     Open vSwitch initiates and maintains  persistent  connec‐
                     tions  to  primary  controllers,  retrying the connection
                     each time it fails or drops. The fail_mode column in  the
                     Bridge table applies to primary controllers.

                     Open  vSwitch permits a bridge to have any number of pri‐
                     mary controllers. When multiple controllers  are  config‐
                     ured,  Open  vSwitch  connects  to all of them simultane‐
                     ously. Because OpenFlow 1.0 does not specify how multiple
                     controllers  coordinate  in  interacting  with  a  single
                     switch, more than one primary controller should be speci‐
                     fied  only  if the controllers are themselves designed to
                     coordinate with each other. (The Nicira-defined  NXT_ROLE
                     OpenFlow vendor extension may be useful for this.)

              Service controllers
                     These  kinds  of  OpenFlow controller connections are in‐
                     tended for occasional support and maintenance  use,  e.g.
                     with  ovs-ofctl.  Usually  a  service controller connects
                     only briefly to inspect or  modify  some  of  a  switch’s
                     state.

                     Open  vSwitch  listens for incoming connections from ser‐
                     vice controllers. The service controllers  initiate  and,
                     if  necessary,  maintain  the connections from their end.
                     The fail_mode column in the Bridge table does  not  apply
                     to service controllers.

                     Open  vSwitch  supports configuring any number of service
                     controllers.

       The target determines the type of controller.

   Summary:
       Core Features:
         target                      string
         connection_mode             optional  string,   either   in-band   or
                                     out-of-band
       Controller Failure Detection and Handling:
         max_backoff                 optional integer, at least 1,000
         inactivity_probe            optional integer
       Asynchronous Messages:
         enable_async_messages       optional boolean
         Controller Rate Limiting:
            controller_rate_limit    optional integer, at least 100
            controller_burst_limit   optional integer, at least 25
            Controller Rate Limiting Statistics:
              status : packet-in-TYPE-bypassed
                                     optional  string,  containing an integer,
                                     at least 0
              status : packet-in-TYPE-queued
                                     optional string, containing  an  integer,
                                     at least 0
              status : packet-in-TYPE-dropped
                                     optional  string,  containing an integer,
                                     at least 0
              status : packet-in-TYPE-backlog
                                     optional string, containing  an  integer,
                                     at least 0
       Additional In-Band Configuration:
         local_ip                    optional string
         local_netmask               optional string
         local_gateway               optional string
       Controller Status:
         is_connected                boolean
         role                        optional string, one of master, other, or
                                     slave
         status : last_error         optional string
         status : state              optional string, one of ACTIVE,  BACKOFF,
                                     CONNECTING, IDLE, or VOID
         status : sec_since_connect  optional  string,  containing an integer,
                                     at least 0
         status : sec_since_disconnect
                                     optional string, containing  an  integer,
                                     at least 1
       Connection Parameters:
         other_config : dscp         optional string, containing an integer
       Common Columns:
         external_ids                map of string-string pairs
         other_config                map of string-string pairs

   Details:
     Core Features:

       target: string
              Connection method for controller.

              The  following  connection  methods  are currently supported for
              primary controllers:

              ssl:host[:port]
                     The specified SSL port on the host  at  the  given  host,
                     which can either be a DNS name (if built with unbound li‐
                     brary)  or  an  IP  address.  The  ssl  column   in   the
                     Open_vSwitch  table  must point to a valid SSL configura‐
                     tion when this form is used.

                     If port is not specified, it defaults to 6653.

                     SSL support is an optional feature  that  is  not  always
                     built as part of Open vSwitch.

              tcp:host[:port]
                     The  specified  TCP  port  on the host at the given host,
                     which can either be a DNS name (if built with unbound li‐
                     brary)  or  an  IP  address (IPv4 or IPv6). If host is an
                     IPv6  address,  wrap  it   in   square   brackets,   e.g.
                     tcp:[::1]:6653.

                     If port is not specified, it defaults to 6653.

              The  following  connection  methods  are currently supported for
              service controllers:

              pssl:[port][:host]
                     Listens for SSL connections on the specified TCP port. If
                     host,  which  can either be a DNS name (if built with un‐
                     bound library) or an IP address, is specified, then  con‐
                     nections  are restricted to the resolved or specified lo‐
                     cal IP address (either IPv4 or IPv6). If host is an  IPv6
                     address,    wrap    it    in    square   brackets,   e.g.
                     pssl:6653:[::1].

                     If port is not specified, it defaults to 6653. If host is
                     not specified then it listens only on IPv4 (but not IPv6)
                     addresses. The ssl column in the Open_vSwitch table  must
                     point  to  a  valid  SSL  configuration when this form is
                     used.

                     If port is not specified, it currently to 6653.

                     SSL support is an optional feature  that  is  not  always
                     built as part of Open vSwitch.

              ptcp:[port][:host]
                     Listens  for  connections  on  the specified TCP port. If
                     host, which can either be a DNS name (if built  with  un‐
                     bound  library) or an IP address, is specified, then con‐
                     nections are restricted to the resolved or specified  lo‐
                     cal  IP address (either IPv4 or IPv6). If host is an IPv6
                     address,   wrap   it    in    square    brackets,    e.g.
                     ptcp:6653:[::1]. If host is not specified then it listens
                     only on IPv4 addresses.

                     If port is not specified, it defaults to 6653.

              When multiple controllers are configured for  a  single  bridge,
              the  target values must be unique. Duplicate target values yield
              unspecified results.

       connection_mode: optional string, either in-band or out-of-band
              If it is specified, this setting must be one  of  the  following
              strings  that  describes how Open vSwitch contacts this OpenFlow
              controller over the network:

              in-band
                     In this mode, this controller’s OpenFlow traffic  travels
                     over the bridge associated with the controller. With this
                     setting, Open vSwitch allows traffic to and from the con‐
                     troller  regardless  of the contents of the OpenFlow flow
                     table. (Otherwise, Open vSwitch would never  be  able  to
                     connect to the controller, because it did not have a flow
                     to enable it.) This is the most  common  connection  mode
                     because  it  is not necessary to maintain two independent
                     networks.

              out-of-band
                     In this mode, OpenFlow traffic  uses  a  control  network
                     separate from the bridge associated with this controller,
                     that is, the bridge does not use any of its  own  network
                     devices  to  communicate with the controller. The control
                     network must be configured separately,  before  or  after
                     ovs-vswitchd is started.

              If not specified, the default is implementation-specific.

     Controller Failure Detection and Handling:

       max_backoff: optional integer, at least 1,000
              Maximum  number  of  milliseconds to wait between connection at‐
              tempts. Default is implementation-specific.

       inactivity_probe: optional integer
              Maximum number of milliseconds of idle  time  on  connection  to
              controller  before  sending an inactivity probe message. If Open
              vSwitch does not communicate with the controller for the  speci‐
              fied  number  of seconds, it will send a probe. If a response is
              not received for  the  same  additional  amount  of  time,  Open
              vSwitch  assumes  the connection has been broken and attempts to
              reconnect. Default is implementation-specific. A value of 0 dis‐
              ables inactivity probes.

     Asynchronous Messages:

       OpenFlow  switches send certain messages to controllers spontanenously,
       that is, not in response to any request from the controller. These mes‐
       sages  are  called ``asynchronous messages.’’ These columns allow asyn‐
       chronous messages to be limited or disabled to ensure the best  use  of
       network resources.

       enable_async_messages: optional boolean
              The  OpenFlow  protocol enables asynchronous messages at time of
              connection establishment, which means that a controller can  re‐
              ceive  asynchronous  messages, potentially many of them, even if
              it turns them off immediately after connecting. Set this  column
              to false to change Open vSwitch behavior to disable, by default,
              all  asynchronous  messages.  The   controller   can   use   the
              NXT_SET_ASYNC_CONFIG Nicira extension to OpenFlow to turn on any
              messages that it does want to receive, if any.

     Controller Rate Limiting:

       A switch can forward packets to a controller over the  OpenFlow  proto‐
       col.  Forwarding  packets  this  way at too high a rate can overwhelm a
       controller, frustrate use of the OpenFlow  connection  for  other  pur‐
       poses,  increase  the  latency  of  flow setup, and use an unreasonable
       amount of bandwidth. Therefore, Open vSwitch supports limiting the rate
       of packet forwarding to a controller.

       There  are  two  main  reasons in OpenFlow for a packet to be sent to a
       controller: either the packet ``misses’’ in the flow  table,  that  is,
       there  is  no  matching  flow,  or a flow table action says to send the
       packet to the controller. Open vSwitch limits the rate of each kind  of
       packet  separately  at  the configured rate. Therefore, the actual rate
       that packets are sent to the controller can be up to twice the  config‐
       ured rate, when packets are sent for both reasons.

       This feature is specific to forwarding packets over an OpenFlow connec‐
       tion. It is not general-purpose QoS. See the QoS table for  quality  of
       service configuration, and ingress_policing_rate in the Interface table
       for ingress policing configuration.

       controller_rate_limit: optional integer, at least 100
              The maximum rate at which the switch will forward packets to the
              OpenFlow controller, in packets per second. If no value is spec‐
              ified, rate limiting is disabled.

       controller_burst_limit: optional integer, at least 25
              When a high rate triggers  rate-limiting,  Open  vSwitch  queues
              packets  to  the  controller for each port and transmits them to
              the controller at the configured rate.  This  value  limits  the
              number  of  queued  packets.  Ports on a bridge share the packet
              queue fairly.

              This value has no effect unless controller_rate_limit is config‐
              ured.  The  current  default when this value is not specified is
              one-quarter of controller_rate_limit, meaning that  queuing  can
              delay forwarding a packet to the controller by up to 250 ms.

     Controller Rate Limiting Statistics:

       These values report the effects of rate limiting. Their values are rel‐
       ative to establishment of the most recent OpenFlow connection, or since
       rate  limiting was enabled, whichever happened more recently. Each con‐
       sists of two values, one with TYPE replaced by miss for  rate  limiting
       flow  table misses, and the other with TYPE replaced by action for rate
       limiting packets sent by OpenFlow actions.

       These statistics are reported only when controller rate limiting is en‐
       abled.

       status  : packet-in-TYPE-bypassed: optional string, containing an inte‐
       ger, at least 0
              Number of packets sent directly to the controller, without queu‐
              ing, because the rate did not exceed the configured maximum.

       status : packet-in-TYPE-queued: optional string, containing an integer,
       at least 0
              Number of packets added to the queue to send later.

       status : packet-in-TYPE-dropped: optional string, containing  an  inte‐
       ger, at least 0
              Number of packets added to the queue that were later dropped due
              to overflow. This value is less than or equal to  status:packet-
              in-TYPE-queued.

       status  :  packet-in-TYPE-backlog: optional string, containing an inte‐
       ger, at least 0
              Number of packets currently queued.  The  other  statistics  in‐
              crease  monotonically, but this one fluctuates between 0 and the
              controller_burst_limit as conditions change.

     Additional In-Band Configuration:

       These values are considered only in in-band control mode  (see  connec
       tion_mode).

       When  multiple  controllers  are  configured  on a single bridge, there
       should be only one set of unique values in these columns. If  different
       values  are  set for these columns in different controllers, the effect
       is unspecified.

       local_ip: optional string
              The  IP  address  to  configure  on   the   local   port,   e.g.
              192.168.0.123.  If  this  value is unset, then local_netmask and
              local_gateway are ignored.

       local_netmask: optional string
              The  IP  netmask  to  configure  on   the   local   port,   e.g.
              255.255.255.0.  If local_ip is set but this value is unset, then
              the default is chosen based on whether the IP address  is  class
              A, B, or C.

       local_gateway: optional string
              The IP address of the gateway to configure on the local port, as
              a string, e.g. 192.168.0.1. Leave this column unset if this net‐
              work has no gateway.

     Controller Status:

       is_connected: boolean
              true if currently connected to this controller, false otherwise.

       role: optional string, one of master, other, or slave
              The  level  of  authority  this controller has on the associated
              bridge. Possible values are:

              other  Allows the controller access to all OpenFlow features.

              master Equivalent to other, except that there may be at most one
                     master controller at a time. When a controller configures
                     itself as master, any existing master is demoted  to  the
                     slave role.

              slave  Allows  the  controller read-only access to OpenFlow fea‐
                     tures. Attempts to modify the flow table will be rejected
                     with   an   error.   Slave  controllers  do  not  receive
                     OFPT_PACKET_IN or OFPT_FLOW_REMOVED messages, but they do
                     receive OFPT_PORT_STATUS messages.

       status : last_error: optional string
              A human-readable description of the last error on the connection
              to the controller; i.e. strerror(errno).  This  key  will  exist
              only if an error has occurred.

       status  :  state:  optional string, one of ACTIVE, BACKOFF, CONNECTING,
       IDLE, or VOID
              The state of the connection to the controller:

              VOID   Connection is disabled.

              BACKOFF
                     Attempting to reconnect at an increasing period.

              CONNECTING
                     Attempting to connect.

              ACTIVE Connected, remote host responsive.

              IDLE   Connection is idle. Waiting for response to keep-alive.

              These values may change in the future. They  are  provided  only
              for human consumption.

       status  : sec_since_connect: optional string, containing an integer, at
       least 0
              The amount of time since this controller last successfully  con‐
              nected  to the switch (in seconds). Value is empty if controller
              has never successfully connected.

       status : sec_since_disconnect: optional string, containing an  integer,
       at least 1
              The  amount of time since this controller last disconnected from
              the switch (in seconds). Value is empty if controller has  never
              disconnected.

     Connection Parameters:

       Additional  configuration  for  a connection between the controller and
       the Open vSwitch.

       other_config : dscp: optional string, containing an integer
              The Differentiated Service Code Point (DSCP) is specified  using
              6 bits in the Type of Service (TOS) field in the IP header. DSCP
              provides a mechanism to classify the network traffic and provide
              Quality  of  Service (QoS) on IP networks. The DSCP value speci‐
              fied here is used when establishing the connection  between  the
              controller and the Open vSwitch. If no value is specified, a de‐
              fault value of 48 is chosen. Valid DSCP values must  be  in  the
              range 0 to 63.

     Common Columns:

       The  overall purpose of these columns is described under Common Columns
       at the beginning of this document.

       external_ids: map of string-string pairs

       other_config: map of string-string pairs

Manager TABLE
       Configuration for a database connection to  an  Open  vSwitch  database
       (OVSDB) client.

       This   table   primarily   configures   the   Open   vSwitch   database
       (ovsdb-server), not the Open vSwitch switch (ovs-vswitchd). The  switch
       does  read the table to determine what connections should be treated as
       in-band.

       The Open vSwitch database server can initiate and maintain active  con‐
       nections  to  remote  clients.  It can also listen for database connec‐
       tions.

   Summary:
       Core Features:
         target                      string (must be unique within table)
         connection_mode             optional  string,   either   in-band   or
                                     out-of-band
       Client Failure Detection and Handling:
         max_backoff                 optional integer, at least 1,000
         inactivity_probe            optional integer
       Status:
         is_connected                boolean
         status : last_error         optional string
         status : state              optional  string, one of ACTIVE, BACKOFF,
                                     CONNECTING, IDLE, or VOID
         status : sec_since_connect  optional string, containing  an  integer,
                                     at least 0
         status : sec_since_disconnect
                                     optional  string,  containing an integer,
                                     at least 0
         status : locks_held         optional string
         status : locks_waiting      optional string
         status : locks_lost         optional string
         status : n_connections      optional string, containing  an  integer,
                                     at least 2
         status : bound_port         optional string, containing an integer
       Connection Parameters:
         other_config : dscp         optional string, containing an integer
       Common Columns:
         external_ids                map of string-string pairs
         other_config                map of string-string pairs

   Details:
     Core Features:

       target: string (must be unique within table)
              Connection method for managers.

              The following connection methods are currently supported:

              ssl:host[:port]
                     The  specified  SSL  port  on the host at the given host,
                     which can either be a DNS name (if built with unbound li‐
                     brary)   or   an  IP  address.  The  ssl  column  in  the
                     Open_vSwitch table must point to a valid  SSL  configura‐
                     tion when this form is used.

                     If port is not specified, it defaults to 6640.

                     SSL  support  is  an  optional feature that is not always
                     built as part of Open vSwitch.

              tcp:host[:port]
                     The specified TCP port on the host  at  the  given  host,
                     which can either be a DNS name (if built with unbound li‐
                     brary) or an IP address (IPv4 or IPv6).  If  host  is  an
                     IPv6   address,   wrap   it   in  square  brackets,  e.g.
                     tcp:[::1]:6640.

                     If port is not specified, it defaults to 6640.

              pssl:[port][:host]
                     Listens for SSL connections on the  specified  TCP  port.
                     Specify  0  for  port  to  have  the kernel automatically
                     choose an available port. If host, which can either be  a
                     DNS  name  (if  built  with unbound library) or an IP ad‐
                     dress, is specified, then connections are  restricted  to
                     the  resolved  or specified local IP address (either IPv4
                     or IPv6 address). If host is an  IPv6  address,  wrap  in
                     square  brackets,  e.g.  pssl:6640:[::1].  If host is not
                     specified then it listens only on IPv4 (but not IPv6) ad‐
                     dresses.  The  ssl  column in the Open_vSwitch table must
                     point to a valid SSL  configuration  when  this  form  is
                     used.

                     If port is not specified, it defaults to 6640.

                     SSL  support  is  an  optional feature that is not always
                     built as part of Open vSwitch.

              ptcp:[port][:host]
                     Listens for connections on the specified TCP port.  Spec‐
                     ify 0 for port to have the kernel automatically choose an
                     available port. If host, which can either be a  DNS  name
                     (if  built  with  unbound  library)  or an IP address, is
                     specified, then connections are  restricted  to  the  re‐
                     solved or specified local IP address (either IPv4 or IPv6
                     address). If host is an IPv6 address, wrap it  in  square
                     brackets,  e.g. ptcp:6640:[::1]. If host is not specified
                     then it listens only on IPv4 addresses.

                     If port is not specified, it defaults to 6640.

              When multiple managers are configured, the target values must be
              unique. Duplicate target values yield unspecified results.

       connection_mode: optional string, either in-band or out-of-band
              If  it  is  specified, this setting must be one of the following
              strings that describes how  Open  vSwitch  contacts  this  OVSDB
              client over the network:

              in-band
                     In  this  mode,  this connection’s traffic travels over a
                     bridge managed by Open vSwitch. With this  setting,  Open
                     vSwitch  allows traffic to and from the client regardless
                     of the contents of the OpenFlow flow  table.  (Otherwise,
                     Open  vSwitch  would  never  be  able  to  connect to the
                     client, because it did not have a  flow  to  enable  it.)
                     This is the most common connection mode because it is not
                     necessary to maintain two independent networks.

              out-of-band
                     In this mode, the client’s traffic uses a control network
                     separate from that managed by Open vSwitch, that is, Open
                     vSwitch does not use any of its own  network  devices  to
                     communicate  with the client. The control network must be
                     configured separately, before or  after  ovs-vswitchd  is
                     started.

              If not specified, the default is implementation-specific.

     Client Failure Detection and Handling:

       max_backoff: optional integer, at least 1,000
              Maximum  number  of  milliseconds to wait between connection at‐
              tempts. Default is implementation-specific.

       inactivity_probe: optional integer
              Maximum number of milliseconds of idle time on connection to the
              client  before  sending  an  inactivity  probe  message. If Open
              vSwitch does not communicate with the client for  the  specified
              number  of  seconds,  it will send a probe. If a response is not
              received for the same additional amount of  time,  Open  vSwitch
              assumes  the  connection  has been broken and attempts to recon‐
              nect. Default is implementation-specific. A value of 0  disables
              inactivity probes.

     Status:

       Key-value pair of is_connected is always updated. Other key-value pairs
       in the status columns may be updated depends on the target type.

       When target specifies a connection method that listens for inbound con‐
       nections  (e.g.  ptcp:  or punix:), both n_connections and is_connected
       may also be updated while the remaining key-value pairs are omitted.

       On the other hand, when target specifies an  outbound  connection,  all
       key-value  pairs  may  be  updated, except the above-mentioned two key-
       value pairs associated with inbound connection targets. They are  omit‐
       ted.

       is_connected: boolean
              true if currently connected to this manager, false otherwise.

       status : last_error: optional string
              A human-readable description of the last error on the connection
              to the manager; i.e. strerror(errno). This key will  exist  only
              if an error has occurred.

       status  :  state:  optional string, one of ACTIVE, BACKOFF, CONNECTING,
       IDLE, or VOID
              The state of the connection to the manager:

              VOID   Connection is disabled.

              BACKOFF
                     Attempting to reconnect at an increasing period.

              CONNECTING
                     Attempting to connect.

              ACTIVE Connected, remote host responsive.

              IDLE   Connection is idle. Waiting for response to keep-alive.

              These values may change in the future. They  are  provided  only
              for human consumption.

       status  : sec_since_connect: optional string, containing an integer, at
       least 0
              The amount of time since this  manager  last  successfully  con‐
              nected  to  the database (in seconds). Value is empty if manager
              has never successfully connected.

       status : sec_since_disconnect: optional string, containing an  integer,
       at least 0
              The amount of time since this manager last disconnected from the
              database (in seconds). Value is empty if manager has never  dis‐
              connected.

       status : locks_held: optional string
              Space-separated  list  of the names of OVSDB locks that the con‐
              nection holds. Omitted if  the  connection  does  not  hold  any
              locks.

       status : locks_waiting: optional string
              Space-separated  list  of the names of OVSDB locks that the con‐
              nection is currently waiting to acquire. Omitted if the  connec‐
              tion is not waiting for any locks.

       status : locks_lost: optional string
              Space-separated  list  of the names of OVSDB locks that the con‐
              nection has had stolen by another OVSDB client.  Omitted  if  no
              locks have been stolen from this connection.

       status  :  n_connections:  optional  string,  containing an integer, at
       least 2
              When target specifies a connection method that listens  for  in‐
              bound  connections  (e.g. ptcp: or pssl:) and more than one con‐
              nection is actually active, the value is the  number  of  active
              connections. Otherwise, this key-value pair is omitted.

       status : bound_port: optional string, containing an integer
              When target is ptcp: or pssl:, this is the TCP port on which the
              OVSDB server is listening. (This  is  particularly  useful  when
              target  specifies a port of 0, allowing the kernel to choose any
              available port.)

     Connection Parameters:

       Additional configuration for a connection between the manager  and  the
       Open vSwitch Database.

       other_config : dscp: optional string, containing an integer
              The  Differentiated Service Code Point (DSCP) is specified using
              6 bits in the Type of Service (TOS) field in the IP header. DSCP
              provides a mechanism to classify the network traffic and provide
              Quality of Service (QoS) on IP networks. The DSCP  value  speci‐
              fied  here  is used when establishing the connection between the
              manager and the Open vSwitch. If no value is  specified,  a  de‐
              fault  value  of  48 is chosen. Valid DSCP values must be in the
              range 0 to 63.

     Common Columns:

       The overall purpose of these columns is described under Common  Columns
       at the beginning of this document.

       external_ids: map of string-string pairs

       other_config: map of string-string pairs

NetFlow TABLE
       A  NetFlow  target.  NetFlow is a protocol that exports a number of de‐
       tails about terminating IP flows, such as the principals  involved  and
       duration.

   Summary:
       targets                       set of 1 or more strings
       engine_id                     optional integer, in range 0 to 255
       engine_type                   optional integer, in range 0 to 255
       active_timeout                integer, at least -1
       add_id_to_interface           boolean
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       targets: set of 1 or more strings
              NetFlow  targets  in  the form ip:port. The ip must be specified
              numerically, not as a DNS name.

       engine_id: optional integer, in range 0 to 255
              Engine ID to use in NetFlow messages. Defaults to datapath index
              if not specified.

       engine_type: optional integer, in range 0 to 255
              Engine type to use in NetFlow messages. Defaults to datapath in‐
              dex if not specified.

       active_timeout: integer, at least -1
              The interval at which NetFlow records are sent  for  flows  that
              are  still active, in seconds. A value of 0 requests the default
              timeout (currently 600 seconds); a value of -1  disables  active
              timeouts.

              The  NetFlow passive timeout, for flows that become inactive, is
              not configurable. It will vary depending  on  the  Open  vSwitch
              version, the forms and contents of the OpenFlow flow tables, CPU
              and memory usage, and network activity. A typical passive  time‐
              out is about a second.

       add_id_to_interface: boolean
              If  this  column’s value is false, the ingress and egress inter‐
              face fields of NetFlow flow records are  derived  from  OpenFlow
              port  numbers.  When  it is true, the 7 most significant bits of
              these fields will be replaced by the least significant 7 bits of
              the engine id. This is useful because many NetFlow collectors do
              not expect multiple switches to be  sending  messages  from  the
              same  host,  so  they  do not store the engine information which
              could be used to disambiguate the traffic.

              When this option is enabled, a maximum of  508  ports  are  sup‐
              ported.

     Common Columns:

       The  overall purpose of these columns is described under Common Columns
       at the beginning of this document.

       external_ids: map of string-string pairs

SSL TABLE
       SSL configuration for an Open_vSwitch.

   Summary:
       private_key                   string
       certificate                   string
       ca_cert                       string
       bootstrap_ca_cert             boolean
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       private_key: string
              Name of a PEM file  containing  the  private  key  used  as  the
              switch’s identity for SSL connections to the controller.

       certificate: string
              Name  of a PEM file containing a certificate, signed by the cer‐
              tificate authority (CA) used by the controller and manager, that
              certifies  the  switch’s  private key, identifying a trustworthy
              switch.

       ca_cert: string
              Name of a PEM file containing the CA certificate used to  verify
              that the switch is connected to a trustworthy controller.

       bootstrap_ca_cert: boolean
              If  set to true, then Open vSwitch will attempt to obtain the CA
              certificate from the controller on its first SSL connection  and
              save  it to the named PEM file. If it is successful, it will im‐
              mediately drop the connection and reconnect, and  from  then  on
              all  SSL  connections  must  be  authenticated  by a certificate
              signed by the CA certificate thus obtained. This option  exposes
              the  SSL  connection to a man-in-the-middle attack obtaining the
              initial CA certificate. It may still be  useful  for  bootstrap‐
              ping.

     Common Columns:

       The  overall purpose of these columns is described under Common Columns
       at the beginning of this document.

       external_ids: map of string-string pairs

sFlow TABLE
       A set of sFlow(R) targets. sFlow is a protocol for remote monitoring of
       switches.

   Summary:
       agent                         optional string
       header                        optional integer
       polling                       optional integer
       sampling                      optional integer
       targets                       set of 1 or more strings
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       agent: optional string
              Determines  the  agent address, that is, the IP address reported
              to collectors as the source of the sFlow data. It may be  an  IP
              address or the name of a network device. In the latter case, the
              network device’s IP address is used,

              If not specified, the agent device is  figured  from  the  first
              target  address and the routing table. If the routing table does
              not contain a route to the target, the IP  address  defaults  to
              the local_ip in the collector’s Controller.

              If an agent IP address cannot be determined, sFlow is disabled.

       header: optional integer
              Number of bytes of a sampled packet to send to the collector. If
              not specified, the default is 128 bytes.

       polling: optional integer
              Polling rate in seconds to send port statistics to  the  collec‐
              tor. If not specified, defaults to 30 seconds.

       sampling: optional integer
              Rate  at which packets should be sampled and sent to the collec‐
              tor. If not specified, defaults to 400, which means one  out  of
              400 packets, on average, will be sent to the collector.

       targets: set of 1 or more strings
              sFlow targets in the form ip:port.

     Common Columns:

       The  overall purpose of these columns is described under Common Columns
       at the beginning of this document.

       external_ids: map of string-string pairs

IPFIX TABLE
       Configuration for sending packets to IPFIX collectors.

       IPFIX is a protocol that exports a number of details about  flows.  The
       IPFIX  implementation in Open vSwitch samples packets at a configurable
       rate, extracts flow information from those packets,  optionally  caches
       and  aggregates  the  flow  information, and sends the result to one or
       more collectors.

       IPFIX in Open vSwitch can be configured two different ways:

              •      With per-bridge sampling,  Open  vSwitch  performs  IPFIX
                     sampling automatically on all packets that pass through a
                     bridge. To configure per-bridge sampling, create an IPFIX
                     record and point a Bridge table’s ipfix column to it. The
                     Flow_Sample_Collector_Set table  is  not  used  for  per-
                     bridge sampling.

              •      With  flow-based sampling, sample actions in the OpenFlow
                     flow table drive IPFIX sampling. See ovs-actions(7) for a
                     description of the sample action.

                     Flow-based sampling also requires database configuration:
                     create a IPFIX record that describes the IPFIX configura‐
                     tion  and  a Flow_Sample_Collector_Set record that points
                     to the Bridge whose flow table holds the  sample  actions
                     and to IPFIX record. The ipfix in the Bridge table is not
                     used for flow-based sampling.

   Summary:
       targets                       set of strings
       cache_active_timeout          optional integer, in range 0 to 4,200
       cache_max_flows               optional   integer,   in   range   0   to
                                     4,294,967,295
       other_config : enable-tunnel-sampling
                                     optional string, either true or false
       other_config : virtual_obs_id optional string
       Per-Bridge Sampling:
         sampling                    optional   integer,   in   range   1   to
                                     4,294,967,295
         obs_domain_id               optional   integer,   in   range   0   to
                                     4,294,967,295
         obs_point_id                optional   integer,   in   range   0   to
                                     4,294,967,295
         other_config : enable-input-sampling
                                     optional string, either true or false
         other_config : enable-output-sampling
                                     optional string, either true or false
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       targets: set of strings
              IPFIX target collectors in the form ip:port.

       cache_active_timeout: optional integer, in range 0 to 4,200
              The maximum period in seconds for which an IPFIX flow record  is
              cached  and  aggregated before being sent. If not specified, de‐
              faults to 0. If 0, caching is disabled.

       cache_max_flows: optional integer, in range 0 to 4,294,967,295
              The maximum number of IPFIX flow records that can be cached at a
              time.  If  not  specified,  defaults to 0. If 0, caching is dis‐
              abled.

       other_config : enable-tunnel-sampling: optional string, either true  or
       false
              Set to true to enable sampling and reporting tunnel header 7-tu‐
              ples in IPFIX flow records. Tunnel sampling is  enabled  by  de‐
              fault.

              The  following  enterprise  entities  report  the sampled tunnel
              info:

              tunnelType:
                     ID: 891, and enterprise ID 6876 (VMware).

                     type: unsigned 8-bit integer.

                     data type semantics: identifier.

                     description: Identifier of the layer  2  network  overlay
                     network  encapsulation  type:  0x01 VxLAN, 0x02 GRE, 0x03
                     LISP, 0x07 GENEVE.

              tunnelKey:
                     ID: 892, and enterprise ID 6876 (VMware).

                     type: variable-length octetarray.

                     data type semantics: identifier.

                     description: Key which is used for identifying  an  indi‐
                     vidual  traffic  flow within a VxLAN (24-bit VNI), GENEVE
                     (24-bit VNI), GRE (32-bit key), or LISP (24-bit  instance
                     ID)  tunnel.  The  key is encoded in this octetarray as a
                     3-, 4-, or 8-byte integer ID in network byte order.

              tunnelSourceIPv4Address:
                     ID: 893, and enterprise ID 6876 (VMware).

                     type: unsigned 32-bit integer.

                     data type semantics: identifier.

                     description: The IPv4 source address  in  the  tunnel  IP
                     packet header.

              tunnelDestinationIPv4Address:
                     ID: 894, and enterprise ID 6876 (VMware).

                     type: unsigned 32-bit integer.

                     data type semantics: identifier.

                     description:  The  IPv4 destination address in the tunnel
                     IP packet header.

              tunnelProtocolIdentifier:
                     ID: 895, and enterprise ID 6876 (VMware).

                     type: unsigned 8-bit integer.

                     data type semantics: identifier.

                     description: The value of the protocol number in the tun‐
                     nel  IP packet header. The protocol number identifies the
                     tunnel IP packet payload type.

              tunnelSourceTransportPort:
                     ID: 896, and enterprise ID 6876 (VMware).

                     type: unsigned 16-bit integer.

                     data type semantics: identifier.

                     description: The source port  identifier  in  the  tunnel
                     transport  header.  For the transport protocols UDP, TCP,
                     and SCTP, this is the source port number given in the re‐
                     spective header.

              tunnelDestinationTransportPort:
                     ID: 897, and enterprise ID 6876 (VMware).

                     type: unsigned 16-bit integer.

                     data type semantics: identifier.

                     description:  The destination port identifier in the tun‐
                     nel transport header. For the  transport  protocols  UDP,
                     TCP,  and SCTP, this is the destination port number given
                     in the respective header.

              Before Open vSwitch 2.5.90,  other_config:enable-tunnel-sampling
              was  only supported with per-bridge sampling, and ignored other‐
              wise. Open vSwitch 2.5.90 and later support other_config:enable-
              tunnel-sampling for per-bridge and per-flow sampling.

       other_config : virtual_obs_id: optional string
              A  string  that accompanies each IPFIX flow record. Its intended
              use is for the ``virtual observation ID,’’ an  identifier  of  a
              virtual  observation  point  that is locally unique in a virtual
              network. It describes a location in the virtual network where IP
              packets can be observed. The maximum length is 254 bytes. If not
              specified, the field is omitted from the IPFIX flow record.

              The following enterprise entity reports  the  specified  virtual
              observation ID:

              virtualObsID:
                     ID: 898, and enterprise ID 6876 (VMware).

                     type: variable-length string.

                     data type semantics: identifier.

                     description:  A virtual observation domain ID that is lo‐
                     cally unique in a virtual network.

              This feature was introduced in Open vSwitch 2.5.90.

     Per-Bridge Sampling:

       These values affect only per-bridge sampling. See above for a  descrip‐
       tion of the differences between per-bridge and flow-based sampling.

       sampling: optional integer, in range 1 to 4,294,967,295
              The  rate  at  which  packets should be sampled and sent to each
              target collector. If not specified, defaults to 400, which means
              one  out of 400 packets, on average, will be sent to each target
              collector.

       obs_domain_id: optional integer, in range 0 to 4,294,967,295
              The IPFIX Observation Domain ID sent in each  IPFIX  packet.  If
              not specified, defaults to 0.

       obs_point_id: optional integer, in range 0 to 4,294,967,295
              The  IPFIX  Observation Point ID sent in each IPFIX flow record.
              If not specified, defaults to 0.

       other_config : enable-input-sampling: optional string, either  true  or
       false
              By  default,  Open  vSwitch  samples and reports flows at bridge
              port input in IPFIX flow records. Set this column  to  false  to
              disable input sampling.

       other_config  : enable-output-sampling: optional string, either true or
       false
              By default, Open vSwitch samples and  reports  flows  at  bridge
              port  output  in IPFIX flow records. Set this column to false to
              disable output sampling.

     Common Columns:

       The overall purpose of these columns is described under Common  Columns
       at the beginning of this document.

       external_ids: map of string-string pairs

Flow_Sample_Collector_Set TABLE
       A  set of IPFIX collectors of packet samples generated by OpenFlow sam
       ple actions. This table is used only for IPFIX flow-based sampling, not
       for  per-bridge  sampling (see the IPFIX table for a description of the
       two forms).

   Summary:
       id                            integer, in range 0 to 4,294,967,295
       bridge                        Bridge
       ipfix                         optional IPFIX
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       id: integer, in range 0 to 4,294,967,295
              The ID of this collector set, unique among the bridge’s  collec‐
              tor  sets, to be used as the collector_set_id in OpenFlow sample
              actions.

       bridge: Bridge
              The bridge into which OpenFlow sample actions can  be  added  to
              send packet samples to this set of IPFIX collectors.

       ipfix: optional IPFIX
              Configuration  of  the  set of IPFIX collectors to send one flow
              record per sampled packet to.

     Common Columns:

       The overall purpose of these columns is described under Common  Columns
       at the beginning of this document.

       external_ids: map of string-string pairs

AutoAttach TABLE
       Auto  Attach  configuration  within a bridge. The IETF Auto-Attach SPBM
       draft standard describes a compact method of using  IEEE  802.1AB  Link
       Layer  Discovery  Protocol (LLDP) together with a IEEE 802.1aq Shortest
       Path Bridging (SPB) network to automatically attach network devices  to
       individual  services in a SPB network. The intent here is to allow net‐
       work applications and devices using OVS to be able to easily  take  ad‐
       vantage of features offered by industry standard SPB networks.

       Auto  Attach (AA) uses LLDP to communicate between a directly connected
       Auto Attach Client (AAC) and Auto Attach Server (AAS). The LLDP  proto‐
       col  is  extended  to  add two new Type-Length-Value tuples (TLVs). The
       first new TLV supports the ongoing discovery of directly  connected  AA
       correspondents.  Auto Attach operates by regularly transmitting AA dis‐
       covery TLVs between the AA client and AA server.  By  exchanging  these
       discovery messages, both the AAC and AAS learn the system name and sys‐
       tem description of their peer. In the OVS context, OVS operates as  the
       AA  client and the AA server resides on a switch at the edge of the SPB
       network.

       Once AA discovery has been completed the AAC then uses the  second  new
       TLV  to  deliver identifier mappings from the AAC to the AAS. A primary
       feature of Auto Attach is to facilitate the mapping  of  VLANs  defined
       outside the SPB network onto service ids (ISIDs) defined within the SPM
       network. By doing so individual external VLANs can be mapped onto  spe‐
       cific  SPB network services. These VLAN id to ISID mappings can be con‐
       figured and managed locally using new options added  to  the  ovs-vsctl
       command.

       The  Auto  Attach OVS feature does not provide a full implementation of
       the LLDP protocol. Support for the mandatory TLVs  as  defined  by  the
       LLDP  standard  and support for the AA TLV extensions is provided. LLDP
       protocol support in OVS can be enabled or disabled on a  port  by  port
       basis. LLDP support is disabled by default.

   Summary:
       system_name                   string
       system_description            string
       mappings                      map  of  integer-integer  pairs,  key  in
                                     range 0 to 16,777,215, value in  range  0
                                     to 4,095

   Details:
       system_name: string
              The  system_name  string is exported in LLDP messages. It should
              uniquely identify the bridge in the network.

       system_description: string
              The system_description string is exported in LLDP  messages.  It
              should describe the type of software and hardware.

       mappings:  map  of integer-integer pairs, key in range 0 to 16,777,215,
       value in range 0 to 4,095
              A mapping from SPB network Individual Service Identifier  (ISID)
              to VLAN id.



Open vSwitch 2.11.90            DB Schema 7.16.1       ovs-vswitchd.conf.db(5)