ovs-vswitchd(8)               Open vSwitch Manual              ovs-vswitchd(8)



NAME
       ovs-vswitchd - Open vSwitch daemon

SYNOPSIS
       ovs-vswitchd [database]

DESCRIPTION
       A  daemon that manages and controls any number of Open vSwitch switches
       on the local machine.

       The  database  argument  specifies   how   ovs-vswitchd   connects   to
       ovsdb-server.   database  may  be an OVSDB active or passive connection
       method, as described in ovsdb(7).  The default  is  unix:/var/run/open‐
       vswitch/db.sock.

       ovs-vswitchd  retrieves its configuration from database at startup.  It
       sets up Open vSwitch datapaths and then operates switching across  each
       bridge  described in its configuration files.  As the database changes,
       ovs-vswitchd automatically updates its configuration to match.

       ovs-vswitchd switches may be configured with any of the following  fea‐
       tures:

       ·      L2 switching with MAC learning.

       ·      NIC  bonding  with  automatic  fail-over and source MAC-based TX
              load balancing ("SLB").

       ·      802.1Q VLAN support.

       ·      Port mirroring, with optional VLAN tagging.

       ·      NetFlow v5 flow logging.

       ·      sFlow(R) monitoring.

       ·      Connectivity to an external OpenFlow controller, such as NOX.

       Only a single instance of ovs-vswitchd is intended to run at a time.  A
       single  ovs-vswitchd  can  manage any number of switch instances, up to
       the maximum number of supported Open vSwitch datapaths.

       ovs-vswitchd does all the necessary management of  Open  vSwitch  data‐
       paths  itself.  Thus, ovs-dpctl(8) (and its userspace datapath counter‐
       parts accessible via ovs-appctl  dpctl/command)  are  not  needed  with
       ovs-vswitchd and should not be used because they can interfere with its
       operation.  These tools are still useful for diagnostics.

       An Open vSwitch datapath kernel module must be loaded for  ovs-vswitchd
       to  be  useful.   Refer to the documentation for instructions on how to
       build and load the Open vSwitch kernel module.

OPTIONS
       --mlockall
              Causes ovs-vswitchd to call the mlockall() function, to  attempt
              to  lock all of its process memory into physical RAM, preventing
              the kernel from paging any of its memory to disk.  This helps to
              avoid networking interruptions due to system memory pressure.

              Some systems do not support mlockall() at all, and other systems
              only allow privileged users, such as the superuser, to  use  it.
              ovs-vswitchd emits a log message if mlockall() is unavailable or
              unsuccessful.

   DPDK Options
       For details on initializing ovs-vswitchd to use DPDK  ports,  refer  to
       the documentation or ovs-vswitchd.conf.db(5).

   Daemon Options
       The following options are valid on POSIX based platforms.

       --pidfile[=pidfile]
              Causes a file (by default, ovs-vswitchd.pid) to be created indi‐
              cating the PID of the running process.  If the pidfile  argument
              is  not  specified,  or  if it does not begin with /, then it is
              created in /var/run/openvswitch.

              If --pidfile is not specified, no pidfile is created.

       --overwrite-pidfile
              By default, when --pidfile is specified and the  specified  pid‐
              file  already  exists  and  is  locked  by  a  running  process,
              ovs-vswitchd refuses to start.  Specify  --overwrite-pidfile  to
              cause it to instead overwrite the pidfile.

              When --pidfile is not specified, this option has no effect.

       --detach
              Runs  ovs-vswitchd  as a background process.  The process forks,
              and in the child it starts a new session,  closes  the  standard
              file descriptors (which has the side effect of disabling logging
              to the console), and changes its current directory to  the  root
              (unless --no-chdir is specified).  After the child completes its
              initialization, the parent exits.   ovs-vswitchd  detaches  only
              after  it  has  connected to the database, retrieved the initial
              configuration, and set up that configuration.

       --monitor
              Creates an additional process to monitor the  ovs-vswitchd  dae‐
              mon.   If  the daemon dies due to a signal that indicates a pro‐
              gramming error (SIGABRT, SIGALRM, SIGBUS, SIGFPE,  SIGILL,  SIG‐
              PIPE,  SIGSEGV,  SIGXCPU,  or  SIGXFSZ) then the monitor process
              starts a new copy of it.   If  the  daemon  dies  or  exits  for
              another reason, the monitor process exits.

              This  option  is  normally used with --detach, but it also func‐
              tions without it.

       --no-chdir
              By default, when --detach is specified, ovs-vswitchd changes its
              current  working  directory  to  the  root  directory  after  it
              detaches.  Otherwise, invoking ovs-vswitchd  from  a  carelessly
              chosen directory would prevent the administrator from unmounting
              the file system that holds that directory.

              Specifying  --no-chdir  suppresses  this  behavior,   preventing
              ovs-vswitchd  from changing its current working directory.  This
              may be useful for collecting core  files,  since  it  is  common
              behavior  to write core dumps into the current working directory
              and the root directory is not a good directory to use.

              This option has no effect when --detach is not specified.

       --no-self-confinement
              By default daemon will try to self-confine itself to  work  with
              files  under well-known directories determined during build.  It
              is better to stick with this default behavior  and  not  to  use
              this  flag  unless  some other Access Control is used to confine
              daemon.  Note that in contrast to other access control implemen‐
              tations  that are typically enforced from kernel-space (e.g. DAC
              or MAC), self-confinement is imposed from the user-space  daemon
              itself  and hence should not be considered as a full confinement
              strategy, but instead should be viewed as an additional layer of
              security.

       --user Causes  ovs-vswitchd  to  run  as  a different user specified in
              "user:group", thus dropping most of the root  privileges.  Short
              forms "user" and ":group" are also allowed, with current user or
              group are assumed respectively. Only daemons started by the root
              user accepts this argument.

              On   Linux,   daemons   will   be   granted   CAP_IPC_LOCK   and
              CAP_NET_BIND_SERVICES before dropping root  privileges.  Daemons
              that  interact  with  a  datapath, such as ovs-vswitchd, will be
              granted three  additional  capabilities,  namely  CAP_NET_ADMIN,
              CAP_NET_BROADCAST  and  CAP_NET_RAW.  The capability change will
              apply even if the new user is root.

              On Windows, this option is not currently supported. For security
              reasons,  specifying  this  option will cause the daemon process
              not to start.

   Service Options
       The following options are valid only on Windows platform.

       --service
              Causes ovs-vswitchd to run as a service in the  background.  The
              service  should already have been created through external tools
              like SC.exe.

       --service-monitor
              Causes the ovs-vswitchd service to be automatically restarted by
              the  Windows  services  manager if the service dies or exits for
              unexpected reasons.

              When --service is not specified, this option has no effect.

   Public Key Infrastructure Options
       -p privkey.pem
       --private-key=privkey.pem
              Specifies  a  PEM  file  containing  the  private  key  used  as
              ovs-vswitchd's identity for outgoing SSL connections.

       -c cert.pem
       --certificate=cert.pem
              Specifies a PEM file containing a certificate that certifies the
              private key specified on -p or --private-key to be  trustworthy.
              The certificate must be signed by the certificate authority (CA)
              that the peer in SSL connections will use to verify it.

       -C cacert.pem
       --ca-cert=cacert.pem
              Specifies  a  PEM  file  containing  the  CA  certificate   that
              ovs-vswitchd  should  use to verify certificates presented to it
              by SSL peers.  (This may be the same certificate that SSL  peers
              use  to verify the certificate specified on -c or --certificate,
              or it may be a different one, depending on  the  PKI  design  in
              use.)

       -C none
       --ca-cert=none
              Disables  verification  of  certificates presented by SSL peers.
              This introduces a security risk, because it means that  certifi‐
              cates cannot be verified to be those of known trusted hosts.

       --bootstrap-ca-cert=cacert.pem
              When cacert.pem exists, this option has the same effect as -C or
              --ca-cert.  If it does not exist, then ovs-vswitchd will attempt
              to  obtain the CA certificate from the SSL peer on its first SSL
              connection and save it to the named PEM file.  If it is success‐
              ful,  it will immediately drop the connection and reconnect, and
              from then on all SSL connections must be authenticated by a cer‐
              tificate 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, but it may be  use‐
              ful for bootstrapping.

              This option is only useful if the SSL peer sends its CA certifi‐
              cate as part of the SSL certificate  chain.   The  SSL  protocol
              does not require the server to send the CA certificate.

              This option is mutually exclusive with -C and --ca-cert.

       --peer-ca-cert=peer-cacert.pem
              Specifies  a  PEM file that contains one or more additional cer‐
              tificates to send to SSL peers.  peer-cacert.pem should  be  the
              CA certificate used to sign ovs-vswitchd's own certificate, that
              is, the  certificate  specified  on  -c  or  --certificate.   If
              ovs-vswitchd's  certificate  is  self-signed, then --certificate
              and --peer-ca-cert should specify the same file.

              This option is not useful in normal operation, because  the  SSL
              peer  must  already have the CA certificate for the peer to have
              any confidence in ovs-vswitchd's identity.  However, this offers
              a  way for a new installation to bootstrap the CA certificate on
              its first SSL connection.

   Logging Options
       -v[spec]
       --verbose=[spec]
              Sets logging levels.  Without any spec, sets the log  level  for
              every  module and destination to dbg.  Otherwise, spec is a list
              of words separated by spaces or commas or colons, up to one from
              each category below:

              ·      A  valid  module name, as displayed by the vlog/list com‐
                     mand on ovs-appctl(8), limits the log level change to the
                     specified module.

              ·      syslog,  console,  or file, to limit the log level change
                     to only to the system log, to the console, or to a  file,
                     respectively.   (If  --detach  is specified, ovs-vswitchd
                     closes its standard file descriptors, so logging  to  the
                     console will have no effect.)

                     On  Windows platform, syslog is accepted as a word and is
                     only useful along with the  --syslog-target  option  (the
                     word has no effect otherwise).

              ·      off,  emer,  err,  warn, info, or dbg, to control the log
                     level.  Messages of the given severity or higher will  be
                     logged,  and  messages of lower severity will be filtered
                     out.  off filters out all  messages.   See  ovs-appctl(8)
                     for a definition of each log level.

              Case is not significant within spec.

              Regardless  of  the  log  levels set for file, logging to a file
              will not take place unless --log-file  is  also  specified  (see
              below).

              For compatibility with older versions of OVS, any is accepted as
              a word but has no effect.

       -v
       --verbose
              Sets the maximum logging verbosity level, equivalent  to  --ver‐
              bose=dbg.

       -vPATTERN:destination:pattern
       --verbose=PATTERN:destination:pattern
              Sets  the  log  pattern  for  destination  to pattern.  Refer to
              ovs-appctl(8) for a description of the valid syntax for pattern.

       -vFACILITY:facility
       --verbose=FACILITY:facility
              Sets the RFC5424 facility of the log message.  facility  can  be
              one  of kern, user, mail, daemon, auth, syslog, lpr, news, uucp,
              clock, ftp, ntp, audit, alert, clock2, local0,  local1,  local2,
              local3,  local4, local5, local6 or local7. If this option is not
              specified, daemon is used as the default for  the  local  system
              syslog  and local0 is used while sending a message to the target
              provided via the --syslog-target option.

       --log-file[=file]
              Enables logging to a file.  If file is  specified,  then  it  is
              used  as  the exact name for the log file.  The default log file
              name   used   if   file    is    omitted    is    /var/log/open‐
              vswitch/ovs-vswitchd.log.

       --syslog-target=host:port
              Send  syslog  messages  to  UDP port on host, in addition to the
              system syslog.  The host must be a numerical IP address,  not  a
              hostname.

       --syslog-method=method
              Specify method how syslog messages should be sent to syslog dae‐
              mon.  Following forms are supported:

              ·      libc, use libc syslog() function.  Downside of using this
                     options  is  that libc adds fixed prefix to every message
                     before it is actually sent  to  the  syslog  daemon  over
                     /dev/log UNIX domain socket.

              ·      unix:file, use UNIX domain socket directly.  It is possi‐
                     ble to specify arbitrary message format with this option.
                     However,  rsyslogd  8.9 and older versions use hard coded
                     parser function anyway that  limits  UNIX  domain  socket
                     use.   If  you  want to use arbitrary message format with
                     older rsyslogd versions, then use UDP socket to localhost
                     IP address instead.

              ·      udp:ip:port, use UDP socket.  With this method it is pos‐
                     sible to use arbitrary message  format  also  with  older
                     rsyslogd.   When  sending syslog messages over UDP socket
                     extra precaution needs to  be  taken  into  account,  for
                     example,  syslog  daemon needs to be configured to listen
                     on the specified  UDP  port,  accidental  iptables  rules
                     could  be interfering with local syslog traffic and there
                     are some security considerations that apply to UDP  sock‐
                     ets, but do not apply to UNIX domain sockets.

              ·      null, discards all messages logged to syslog.

              The  default  is  taken  from  the OVS_SYSLOG_METHOD environment
              variable; if it is unset, the default is libc.

   Other Options
       --unixctl=socket
              Sets the name of the control socket on which  ovs-vswitchd  lis‐
              tens  for  runtime  management  commands (see RUNTIME MANAGEMENT
              COMMANDS, below).  If socket does not begin with /, it is inter‐
              preted as relative to /var/run/openvswitch.  If --unixctl is not
              used   at   all,   the   default   socket   is    /var/run/open‐
              vswitch/ovs-vswitchd.pid.ctl,   where   pid   is  ovs-vswitchd's
              process ID.

              On Windows a local named pipe is used to listen for runtime man‐
              agement  commands.   A  file  is created in the absolute path as
              pointed by socket or if --unixctl is not used at all, a file  is
              created  as ovs-vswitchd.ctl in the configured OVS_RUNDIR direc‐
              tory.  The file exists just to mimic  the  behavior  of  a  Unix
              domain socket.

              Specifying none for socket disables the control socket feature.

       -h
       --help Prints a brief help message to the console.

       -V
       --version
              Prints version information to the console.

RUNTIME MANAGEMENT COMMANDS
       ovs-appctl(8) can send commands to a running ovs-vswitchd process.  The
       currently supported commands are described below.  The command descrip‐
       tions assume an understanding of how to configure Open vSwitch.

   GENERAL COMMANDS
       exit --cleanup
              Causes  ovs-vswitchd  to  gracefully  terminate. If --cleanup is
              specified, deletes flows from datapaths and releases other data‐
              path  resources configured by ovs-vswitchd.  Otherwise, datapath
              flows and other resources remains undeleted.  Resources of data‐
              paths  that  are  integrated into ovs-vswitchd (e.g.  the netdev
              datapath type)  are  always  released  regardless  of  --cleanup
              except  for  ports  with internal type. Use --cleanup to release
              internal ports too.

       qos/show-types interface
              Queries the interface for a list of  Quality  of  Service  types
              that are configurable via Open vSwitch for the given interface.

       qos/show interface
              Queries the kernel for Quality of Service configuration and sta‐
              tistics associated with the given interface.

       bfd/show [interface]
              Displays detailed  information  about  Bidirectional  Forwarding
              Detection  configured  on interface.  If interface is not speci‐
              fied, then displays detailed information  about  all  interfaces
              with BFD enabled.

       bfd/set-forwarding [interface] status
              Force  the  fault  status of the BFD module on interface (or all
              interfaces if none is  given)  to  be  status.   status  can  be
              "true",  "false",  or  "normal"  which  reverts  to the standard
              behavior.

       cfm/show [interface]
              Displays detailed information about Connectivity  Fault  Manage‐
              ment  configured  on  interface.  If interface is not specified,
              then displays detailed information about all interfaces with CFM
              enabled.

       cfm/set-fault [interface] status
              Force  the  fault  status of the CFM module on interface (or all
              interfaces if none is  given)  to  be  status.   status  can  be
              "true",  "false",  or  "normal"  which  reverts  to the standard
              behavior.

       stp/tcn [bridge]
              Forces a topology change event on bridge if  it's  running  STP.
              This  may  cause it to send Topology Change Notifications to its
              peers and flush its MAC table.  If no bridge is given, forces  a
              topology change event on all bridges.

       stp/show [bridge]
              Displays detailed information about spanning tree on the bridge.
              If bridge is not specified, then displays  detailed  information
              about all bridges with STP enabled.

       rstp/tcn [bridge]
              Forces  a  topology change event on bridge if it's running RSTP.
              This may cause it to send Topology Change Notifications  to  its
              peers  and flush its MAC table.  If no bridge is given, forces a
              topology change event on all bridges.

       rstp/show [bridge]
              Displays detailed information about rapid spanning tree  on  the
              bridge.   If  bridge  is  not  specified, then displays detailed
              information about all bridges with RSTP enabled.

   BRIDGE COMMANDS
       These commands manage bridges.

       fdb/flush [bridge]
              Flushes bridge MAC  address  learning  table,  or  all  learning
              tables if no bridge is given.

       fdb/show bridge
              Lists  each  MAC  address/VLAN  pair  learned  by  the specified
              bridge, along with the port on which it was learned and the  age
              of the entry, in seconds.

       fdb/stats-clear [bridge]
              Clear  bridge MAC address learning table statistics, or all sta‐
              tistics if no bridge is given.

       fdb/stats-show bridge
              Show MAC address learning table  statistics  for  the  specified
              bridge.

       mdb/flush [bridge]
              Flushes  bridge multicast snooping table, or all snooping tables
              if no bridge is given.

       mdb/show bridge
              Lists each multicast group/VLAN pair learned  by  the  specified
              bridge,  along with the port on which it was learned and the age
              of the entry, in seconds.

       bridge/reconnect [bridge]
              Makes bridge drop all of its OpenFlow controller connections and
              reconnect.   If  bridge  is not specified, then all bridges drop
              their controller connections and reconnect.

              This command might be useful for debugging  OpenFlow  controller
              issues.

       bridge/dump-flows [--offload-stats] bridge
              Lists  all  flows  in bridge, including those normally hidden to
              commands such as ovs-ofctl dump-flows.  Flows set up  by  mecha‐
              nisms  such as in-band control and fail-open are hidden from the
              controller since it is not allowed to modify or  override  them.
              If  --offload-stats  are specified then also list statistics for
              offloaded packets and bytes, which are a  subset  of  the  total
              packets and bytes.

   BOND COMMANDS
       These  commands  manage  bonded ports on an Open vSwitch's bridges.  To
       understand some of these commands, it  is  important  to  understand  a
       detail  of  the bonding implementation called ``source load balancing''
       (SLB).  Instead of directly assigning Ethernet source addresses to mem‐
       bers,  the  bonding  implementation  computes  a  function that maps an
       48-bit Ethernet source addresses into an 8-bit value  (a  ``MAC  hash''
       value).  All of the Ethernet addresses that map to a single 8-bit value
       are then assigned to a single member.

       bond/list
              Lists all of the bonds, and their members, on each bridge.

       bond/show [port]
              Lists all of the bond-specific information (updelay,  downdelay,
              time  until  the next rebalance) about the given bonded port, or
              all bonded ports if no port is given.   Also  lists  information
              about  each members: whether it is enabled or disabled, the time
              to completion of an updelay or downdelay if one is in  progress,
              whether it is the active member, the hashes assigned to the mem‐
              ber.  Any LACP information related to this  bond  may  be  found
              using the lacp/show command.

       bond/migrate port hash member
              Only  valid  for  SLB  bonds.  Assigns a given MAC hash to a new
              member.  port specifies the bond port, hash the MAC hash  to  be
              migrated (as a decimal number between 0 and 255), and member the
              new member to be assigned.

              The reassignment is not permanent: rebalancing or fail-over will
              cause  the  MAC  hash to be shifted to a new member in the usual
              manner.

              A MAC hash cannot be migrated to a disabled member.

       bond/set-active-member port member
              Sets member as the active member on port.  member must currently
              be enabled.

              The  setting  is  not  permanent:  a  new  active member will be
              selected if member becomes disabled.

       bond/enable-member port member
       bond/disable-member port member
              Enables (or disables) member on the given  bond  port,  skipping
              any updelay (or downdelay).

              This  setting  is not permanent: it persists only until the car‐
              rier status of member changes.

       bond/hash mac [vlan] [basis]
              Returns the hash value which would be used for mac with vlan and
              basis if specified.

       lacp/show [port]
              Lists  all of the LACP related information about the given port:
              active or passive, aggregation key, system id, and system prior‐
              ity.   Also  lists  information about each member: whether it is
              enabled or disabled, whether it is attached or detached, port id
              and  priority,  actor  information, and partner information.  If
              port is not specified, then displays detailed information  about
              all interfaces with CFM enabled.

       lacp/stats-show [port]
              Lists  various  stats about LACP PDUs (number of RX/TX PDUs, bad
              PDUs received) and member  state  (number  of  times  its  state
              expired/defaulted  and  carrier  status  changed)  for the given
              port.  If port is not specified,  then  displays  stats  of  all
              interfaces with LACP enabled.

   DPCTL DATAPATH DEBUGGING COMMANDS
       The  primary  way to configure ovs-vswitchd is through the Open vSwitch
       database, e.g. using ovs-vsctl(8).  These commands provide a  debugging
       interface  for  managing  datapaths.   They implement the same features
       (and syntax) as ovs-dpctl(8).  Unlike ovs-dpctl(8), these commands work
       with  datapaths  that are integrated into ovs-vswitchd (e.g. the netdev
       datapath type).

       Do  not  use  commands  to  add  or  remove  or  modify  datapaths   if
       ovs-vswitchd is running because this interferes with ovs-vswitchd's own
       datapath management.

       dpctl/add-dp dp [netdev[,option]...]
              Creates datapath dp, with a local port also named dp.  This will
              fail if a network device dp already exists.

              If  netdevs  are  specified,  ovs-vswitchd  adds them to the new
              datapath, just as if add-if was specified.

       dpctl/del-dp dp
              Deletes datapath dp.  If  dp  is  associated  with  any  network
              devices, they are automatically removed.

       dpctl/add-if dp netdev[,option]...
              Adds each netdev to the set of network devices datapath dp moni‐
              tors, where dp is the name of an existing datapath,  and  netdev
              is  the  name  of  one of the host's network devices, e.g. eth0.
              Once a network device has been added to a datapath, the datapath
              has  complete  ownership of the network device's traffic and the
              network device appears silent to the rest of the system.

              A netdev may be followed by a comma-separated list  of  options.
              The following options are currently supported:

              type=type
                     Specifies  the  type of port to add.  The default type is
                     system.

              port_no=port
                     Requests a specific port number within the datapath.   If
                     this  option  is not specified then one will be automati‐
                     cally assigned.

              key=value
                     Adds an arbitrary key-value option to the port's configu‐
                     ration.

              ovs-vswitchd.conf.db(5)  documents  the available port types and
              options.

       dpctl/set-if dp port[,option]...
              Reconfigures each port in dp as specified.   An  option  of  the
              form  key=value  adds the specified key-value option to the port
              or overrides an existing key's value.  An  option  of  the  form
              key=, that is, without a value, deletes the key-value named key.
              The type and port number of a port cannot be  changed,  so  type
              and port_no are only allowed if they match the existing configu‐
              ration.

       dpctl/del-if dp netdev...
              Removes each netdev from the list of network devices datapath dp
              monitors.

       dpctl/dump-dps
              Prints the name of each configured datapath on a separate line.

       dpctl/show [-s | --statistics] [dp...]
              Prints  a summary of configured datapaths, including their data‐
              path numbers and a list of ports  connected  to  each  datapath.
              (The local port is identified as port 0.)  If -s or --statistics
              is specified, then packet and byte counters are also printed for
              each port.

              The  datapath  numbers consists of flow stats and mega flow mask
              stats.

              The "lookups" row displays three stats related  to  flow  lookup
              triggered  by processing incoming packets in the datapath. "hit"
              displays number of packets matches existing flows. "missed" dis‐
              plays  the  number of packets not matching any existing flow and
              require user space processing.  "lost" displays number of  pack‐
              ets  destined  for  user  space process but subsequently dropped
              before reaching userspace. The sum of "hit" and "miss" equals to
              the total number of packets datapath processed.

              The "flows" row displays the number of flows in datapath.

              The  "masks"  row displays the mega flow mask stats. This row is
              omitted for datapath not implementing mega flow. "hit"  displays
              the total number of masks visited for matching incoming packets.
              "total" displays number of masks in the datapath. "hit/pkt" dis‐
              plays  the average number of masks visited per packet; the ratio
              between "hit" and total number of packets processed by the data‐
              path.

              If  one  or  more  datapaths  are specified, information on only
              those datapaths are displayed.  Otherwise, ovs-vswitchd displays
              information about all configured datapaths.

   DATAPATH FLOW TABLE DEBUGGING COMMANDS
       The following commands are primarily useful for debugging Open vSwitch.
       The flow table entries (both matches and actions) that they  work  with
       are not OpenFlow flow entries.  Instead, they are different and consid‐
       erably simpler flows maintained by the Open vSwitch kernel module.   Do
       not  use  commands  to  add  or  remove  or  modify  datapath  flows if
       ovs-vswitchd is running because it interferes with  ovs-vswitchd's  own
       datapath  flow  management.   Use  ovs-ofctl(8),  instead, to work with
       OpenFlow flow entries.

       The dp argument to each of these commands is optional when exactly  one
       datapath exists, in which case that datapath is the default.  When mul‐
       tiple datapaths exist, then a datapath name is required.

       dpctl/dump-flows [-m | --more] [--names | --no-names] [dp] [filter=fil‐
       ter] [type=type] [pmd=pmd]
              Prints to the console all flow entries in datapath dp's flow ta‐
              ble.  Without -m or --more, output omits  match  fields  that  a
              flow  wildcards entirely; with -m or --more, output includes all
              wildcarded fields.

              If filter=filter is specified,  only  displays  the  flows  that
              match  the filter. filter is a flow in the form similiar to that
              accepted by ovs-ofctl(8)'s add-flow command.  (This  is  not  an
              OpenFlow  flow:  besides  other  differences,  it never contains
              wildcards.)  The filter  is  also  useful  to  match  wildcarded
              fields   in   the   datapath   flow.   As   an   example,   fil‐
              ter='tcp,tp_src=100' will match  the  datapath  flow  containing
              'tcp(src=80/0xff00,dst=8080/0xff)'.

              If  pmd=pmd  is  specified, only displays flows of the specified
              pmd.  Using pmd=-1 will restrict the dump to flows from the main
              thread.   This  option  is only supported by the userspace data‐
              path.

              If type=type is specified, only displays flows of the  specified
              types.     This    option    supported   only   for   ovs-appctl
              dpctl/dump-flows.  type is a comma  separated  list,  which  can
              contain any of the following:
                 ovs - displays flows handled in the ovs dp
                 tc - displays flows handled in the tc dp
                 dpdk - displays flows fully offloaded by dpdk
                 offloaded - displays flows offloaded to the HW
                 non-offloaded - displays flows not offloaded to the HW
                 partially-offloaded - displays flows where only part of their
              proccessing is done in HW
                 all - displays all the types of flows

              By default all the types  of  flows  are  displayed.   ovs-dpctl
              always acts as if the type was ovs.

       dpctl/add-flow [dp] flow actions

       dpctl/mod-flow  [--clear]  [--may-create] [-s | --statistics] [dp] flow
       actions
              Adds or modifies a flow in dp's flow table that, when  a  packet
              matching flow arrives, causes actions to be executed.

              The  add-flow  command  succeeds  only  if flow does not already
              exist in dp.  Contrariwise, mod-flow without  --may-create  only
              modifies  the  actions for an existing flow.  With --may-create,
              mod-flow will add a new flow or modify an existing one.

              If -s or --statistics is specified,  then  mod-flow  prints  the
              modified  flow's statistics.  A flow's statistics are the number
              of packets and bytes that have  passed  through  the  flow,  the
              elapsed  time  since the flow last processed a packet (if ever),
              and (for TCP flows) the union of the TCP flags processed through
              the flow.

              With  --clear,  mod-flow  zeros  out the flow's statistics.  The
              statistics printed if -s or --statistics is also  specified  are
              those from just before clearing the statistics.

              NOTE:  flow  and  actions  do  not  match  the  syntax used with
              ovs-ofctl(8)'s add-flow command.

              Usage Examples

              Forward ARP between ports 1 and 2 on datapath myDP:

                     ovs-dpctl add-flow myDP \
                       "in_port(1),eth(),eth_type(0x0806),arp()" 2

                     ovs-dpctl add-flow myDP \
                       "in_port(2),eth(),eth_type(0x0806),arp()" 1

              Forward all IPv4 traffic between two addresses on ports 1 and 2:

                     ovs-dpctl add-flow myDP \
                       "in_port(1),eth(),eth_type(0x800),\
                        ipv4(src=172.31.110.4,dst=172.31.110.5)" 2

                     ovs-dpctl add-flow myDP \
                       "in_port(2),eth(),eth_type(0x800),\
                        ipv4(src=172.31.110.5,dst=172.31.110.4)" 1

       dpctl/add-flows [dp] file
       dpctl/mod-flows [dp] file
       dpctl/del-flows [dp] file
              Reads flow entries from file (or stdin if file is -)  and  adds,
              modifies,  or  deletes  each  entry  to the datapath.  Each flow
              specification (e.g., each line in file) may start with add, mod‐
              ify, or delete keyword to specify whether a flow is to be added,
              modified, or deleted. A flow specification without one of  these
              keywords is treated based on the used command.  All flow modifi‐
              cations are executed as individual  transactions  in  the  order
              specified.

       dpctl/del-flow [-s | --statistics] [dp] flow
              Deletes  the flow from dp's flow table that matches flow.  If -s
              or --statistics is specified, then del-flow prints  the  deleted
              flow's statistics.

       dpctl/get-flow [dp] ufid:ufid [-m | --more] [--names | --no-names]
              Fetches  the  flow  from  dp's flow table with unique identifier
              ufid.  ufid must be specified as  a  string  of  32  hexadecimal
              characters.

       dpctl/del-flows [dp]
              Deletes all flow entries from datapath dp's flow table.

   CONNECTION TRACKING TABLE COMMANDS
       The  following  commands  are  useful for debugging and configuring the
       connection tracking table in the datapath.

       The dp argument to each of these commands is optional when exactly  one
       datapath exists, in which case that datapath is the default.  When mul‐
       tiple datapaths exist, then a datapath name is required.

       N.B.(Linux specific): the system datapaths (i.e. the Linux kernel  mod‐
       ule  Open  vSwitch  datapaths) share a single connection tracking table
       (which is also used by other kernel subsystems, such as iptables, nfta‐
       bles and the regular host stack).  Therefore, the following commands do
       not apply specifically to one datapath.

       dpctl/ipf-set-enabled [dp] v4|v6
       dpctl/ipf-set-disabled [dp] v4|v6
              Enables or disables IP fragmentation handling for the  userspace
              connection  tracker.   Either  v4 or v6 must be specified.  Both
              IPv4 and IPv6 fragment reassembly are enabled by default.   Only
              supported for the userspace datapath.

       dpctl/ipf-set-min-frag [dp] v4|v6 minfrag
              Sets  the  minimum  fragment  size (L3 header and data) for non-
              final fragments to minfrag.  Either v4 or v6 must be  specified.
              For  enhanced  DOS  security,  higher minimum fragment sizes can
              usually be used.  The default IPv4 value is 1200 and the clamped
              minimum  is 400.  The default IPv6 value is 1280, with a clamped
              minimum of 400, for testing flexibility.  The  maximum  fragment
              size  is not clamped, however, setting this value too high might
              result in valid fragments being  dropped.   Only  supported  for
              userspace datapath.

       dpctl/ipf-set-max-nfrags [dp] maxfrags
              Sets  the  maximum  number of fragments tracked by the userspace
              datapath connection tracker to maxfrags.  The default  value  is
              1000  and the clamped maximum is 5000.  Note that packet buffers
              can be held by the  fragmentation  module  while  fragments  are
              incomplete, but will timeout after 15 seconds.  Memory pool siz‐
              ing should be set accordingly  when  fragmentation  is  enabled.
              Only supported for userspace datapath.

       dpctl/ipf-get-status [dp] [-m | --more]
              Gets the configuration settings and fragment counters associated
              with the fragmentation handling of the userspace  datapath  con‐
              nection  tracker.  With -m or --more, also dumps the IP fragment
              lists.  Only supported for userspace datapath.

       dpctl/dump-conntrack [-m | --more] [-s | --statistics] [dp] [zone=zone]
              Prints to the console all the connection entries in the  tracker
              used  by  dp.  If zone=zone is specified, only shows the connec‐
              tions  in  zone.   With  --more,  some  implementation  specific
              details  are included. With --statistics timeouts and timestamps
              are added to the output.

       dpctl/flush-conntrack [dp] [zone=zone] [ct-tuple]
              Flushes the connection entries in the tracker used by  dp  based
              on  zone and connection tracking tuple ct-tuple.  If ct-tuple is
              not provided, flushes all the connection entries.  If  zone=zone
              is specified, only flushes the connections in zone.

              If  ct-tuple is provided, flushes the connection entry specified
              by ct-tuple in zone. The zone defaults to 0 if it  is  not  pro‐
              vided.   The userspace connection tracker requires flushing with
              the original pre-NATed tuple and a warning log will be otherwise
              generated.  An example of an IPv4 ICMP ct-tuple:

              "ct_nw_src=10.1.1.1,ct_nw_dst=10.1.1.2,ct_nw_proto=1,icmp_type=8,icmp_code=0,icmp_id=10"

              An example of an IPv6 TCP ct-tuple:

              "ct_ipv6_src=fc00::1,ct_ipv6_dst=fc00::2,ct_nw_proto=6,ct_tp_src=1,ct_tp_dst=2"

       dpctl/ct-stats-show [dp] [zone=zone] [-m | --more]
              Displays  the  number of connections grouped by protocol used by
              dp.  If zone=zone is specified, numbers refer to the connections
              in  zone.  With --more, groups by connection state for each pro‐
              tocol.

       dpctl/ct-bkts [dp] [gt=threshold]
              For each conntrack bucket, displays the  number  of  connections
              used  by  dp.   If gt=threshold is specified, bucket numbers are
              displayed when the number of connections in a bucket is  greater
              than threshold.

       dpctl/ct-set-maxconns [dp] maxconns
              Sets the maximum limit of connection tracker entries to maxconns
              on dp.  This can be used to reduce the processing  load  on  the
              system  due to connection tracking or simply limiting connection
              tracking.  If the number of connections is already over the  new
              maximum  limit  request  then  the  new  maximum  limit  will be
              enforced when the number of connections decreases to that limit,
              which normally happens due to connection expiry.  Only supported
              for userspace datapath.

       dpctl/ct-get-maxconns [dp]
              Prints the maximum limit of connection tracker  entries  on  dp.
              Only supported for userspace datapath.

       dpctl/ct-get-nconns [dp]
              Prints  the  current number of connection tracker entries on dp.
              Only supported for userspace datapath.

       dpctl/ct-enable-tcp-seq-chk [dp]
       dpctl/ct-disable-tcp-seq-chk [dp]
              Enables or disables TCP sequence checking.   When  set  to  dis‐
              abled,  all  sequence number verification is disabled, including
              for TCP resets.  This is similar, but not the same  as  'be_lib‐
              eral'  mode, as in Netfilter.  Disabling sequence number verifi‐
              cation is not an optimization in itself, but is needed for  some
              hardware  offload  support  which  might  offer some performance
              advantage. Sequence number checking is  enabled  by  default  to
              enforce  better security and should only be disabled if required
              for hardware offload support.  This command  is  only  supported
              for the userspace datapath.

       dpctl/ct-get-tcp-seq-chk [dp]
              Prints  whether  TCP sequence checking is enabled or disabled on
              dp.  Only supported for the userspace datapath.

       dpctl/ct-set-limits            [dp]             [default=default_limit]
       [zone=zone,limit=limit]...
              Sets  the  maximum allowed number of connections in a connection
              tracking zone.  A specific zone may be set to limit, and  multi‐
              ple  zones  may  be specified with a comma-separated list.  If a
              per-zone limit for a particular zone is  not  specified  in  the
              datapath,  it defaults to the default per-zone limit.  A default
              zone may be specified with the  default=default_limit  argument.
              Initially,  the  default per-zone limit is unlimited.  An unlim‐
              ited number of entries may be set with 0 limit.

       dpctl/ct-del-limits [dp] zone=zone[,zone]...
              Deletes the connection tracking limit for zone.  Multiple  zones
              may be specified with a comma-separated list.

       dpctl/ct-get-limits [dp] [zone=zone[,zone]...]
              Retrieves  the maximum allowed number of connections and current
              counts per-zone.  If zone is given, only the  specified  zone(s)
              are printed.  If no zones are specified, all the zone limits and
              counts are provided.  The command always  displays  the  default
              zone limit.

   DPDK COMMANDS
       These commands manage DPDK components.

       dpdk/log-list
              Lists  all DPDK components that emit logs and their logging lev‐
              els.

       dpdk/log-set [spec]
              Sets DPDK components logging level. Without any spec,  sets  the
              logging  level for all DPDK components to debug. Otherwise, spec
              is a list of words separated by spaces: a word can be  either  a
              logging  level  (emergency,  alert,  critical,  error,  warning,
              notice, info or debug) or a  pattern  matching  DPDK  components
              (see  dpdk/log-list  command  on  ovs-appctl(8))  separated by a
              colon from the logging level to apply.

   DPIF-NETDEV COMMANDS
       These commands are used to expose internal information (mostly  statis‐
       tics)  about the "dpif-netdev" userspace datapath. If there is only one
       datapath (as is often the case, unless dpctl/ commands are  used),  the
       dp  argument  can  be omitted. By default the commands present data for
       all pmd threads in the datapath. By specifying the "-pmd  Core"  option
       one can filter the output for a single pmd in the datapath.

       dpif-netdev/pmd-stats-show [-pmd core] [dp]
              Shows  performance  statistics for one or all pmd threads of the
              datapath dp. The special thread "main" sums up the statistics of
              every non pmd thread.

              The sum of "emc hits", "smc hits", "megaflow hits" and "miss" is
              the number of packet lookups performed by the  datapath.  Beware
              that a recirculated packet experiences one additional lookup per
              recirculation, so there may be more lookups than forwarded pack‐
              ets in the datapath.

              Cycles  are  counted  using  the TSC or similar facilities (when
              available on the platform). The duration of one cycle depends on
              the processing platform.

              "idle  cycles" refers to cycles spent in PMD iterations not for‐
              warding any any packets. "processing cycles"  refers  to  cycles
              spent  in PMD iterations forwarding at least one packet, includ‐
              ing the cost for polling, processing and transmitting said pack‐
              ets.

              To reset these counters use dpif-netdev/pmd-stats-clear.

       dpif-netdev/pmd-stats-clear [dp]
              Resets  to  zero the per pmd thread performance numbers shown by
              the  dpif-netdev/pmd-stats-show  and   dpif-netdev/pmd-perf-show
              commands.  It will NOT reset datapath or bridge statistics, only
              the values shown by the above commands.

       dpif-netdev/pmd-perf-show [-nh] [-it iter_len] [-ms ms_len] [-pmd core]
       [dp]
              Shows  detailed  performance metrics for one or all pmds threads
              of the user space datapath.

              The collection of detailed statistics can be controlled by a new
              configuration   parameter   "other_config:pmd-perf-metrics".  By
              default it is disabled. The run-time overhead, when enabled,  is
              in the order of 1%.


              —      used cycles
              —      forwared packets
              —      number of rx batches
              —      packets/rx batch
              —      max. vhostuser queue fill level
              —      number of upcalls
              —      cycles spent in upcalls

              This raw recorded data is used threefold:


              1.     In histograms for each of the following metrics:
                     —      cycles/iteration (logarithmic)
                     —      packets/iteration (logarithmic)
                     —      cycles/packet
                     —      packets/batch
                     —      max. vhostuser qlen (logarithmic)
                     —      upcalls
                     —      cycles/upcall  (logarithmic)  The  histograms bins
                            are divided linear or logarithmic.
              2.     A cyclic history of the above metrics for 1024 iterations
              3.     A cyclic history of the  cummulative/average  values  per
                     millisecond wall clock for the last 1024 milliseconds:
                     —      number of iterations
                     —      avg. cycles/iteration
                     —      packets (Kpps)
                     —      avg. packets/batch
                     —      avg. max vhost qlen
                     —      upcalls
                     —      avg. cycles/upcall

              The command options are:

              -nh    Suppress the histograms

              -it iter_len
                     Display the last iter_len iteration stats

              -ms ms_len
                     Display the last ms_len millisecond stats

              The output always contains the following global PMD statistics:

                     Time: 15:24:55.270
                     Measurement duration: 1.008 s

                     pmd thread numa_id 0 core_id 1:

                       Iterations:              572817  (1.76 us/it)
                       - Used TSC cycles:   2419034712  ( 99.9 % of total cycles)
                       - idle iterations:       486808  ( 15.9 % of used cycles)
                       - busy iterations:        86009  ( 84.1 % of used cycles)
                       Rx packets:             2399607  (2381 Kpps, 848 cycles/pkt)
                       Datapath passes:        3599415  (1.50 passes/pkt)
                       - EMC hits:              336472  (  9.3 %)
                       - SMC hits:                   0  ( 0.0 %)
                       - Megaflow hits:        3262943  ( 90.7 %, 1.00 subtbl lookups/hit)
                       - Upcalls:                    0  (  0.0 %, 0.0 us/upcall)
                       - Lost upcalls:               0  (  0.0 %)
                       Tx packets:             2399607  (2381 Kpps)
                       Tx batches:              171400  (14.00 pkts/batch)

              Here  "Rx  packets" actually reflects the number of packets for‐
              warded by the datapath. "Datapath passes" matches the number  of
              packet  lookups  as  reported  by the dpif-netdev/pmd-stats-show
              command.

              To reset the counters and start a new measurement use  dpif-net‐
              dev/pmd-stats-clear.

       dpif-netdev/pmd-perf-log-set  on|off  [-b  before]  [-a after] [-e|-ne]
       [-us usec] [-q qlen]
              The userspace "netdev" datapath is able  to  supervise  the  PMD
              performance  metrics  and detect iterations with suspicious sta‐
              tistics according to the following criteria:

              —      The  iteration  lasts  longer  than   usec   microseconds
                     (default  250).  This can be used to capture events where
                     a PMD is blocked or interrupted for such a period of time
                     that there is a risk for dropped packets on any of its Rx
                     queues.

              —      The max vhost qlen  exceeds  a  threshold  qlen  (default
                     128). This can be used to infer virtio queue overruns and
                     dropped packets inside a VM, which are not visible in OVS
                     otherwise.

              Such  suspicious  iterations  can  be logged together with their
              iteration statistics in the ovs-vswitchd.log to be able to  cor‐
              relate them to packet drop or other events outside OVS.

              The above command enables (on) or disables (off) supervision and
              logging at run-time and can be used to adjust the above  thresh‐
              olds for detecting suspicious iterations. By default supervision
              and logging is disabled.

              The command options are:

              -b before
                     The number of iterations before the suspicious  iteration
                     to be logged (default 5).

              -a after
                     The  number  of iterations after the suspicious iteration
                     to be logged (default 5).

              -e     Extend logging interval if another  suspicious  iteration
                     is detected before logging occurs.

              -ne    Do  not  extend  logging  interval  if another suspicious
                     iteration is detected before logging occurs (default).

              -q qlen
                     Suspicious vhost queue  fill  level  threshold.  Increase
                     this to 512 if the Qemu supports 1024 virtio queue length
                     (default 128).

              -us usec
                     Change the duration threshold for a suspicious  iteration
                     (default 250 us).

       Note:  Logging  of suspicious iterations itself consumes a considerable
       amount of processing cycles of a PMD which may be visible in the itera‐
       tion  history.   In  the worst case this can lead OVS to detect another
       suspicious iteration caused by logging.

       If more than 100 iterations around a  suspicious  iteration  have  been
       logged  once, OVS falls back to the safe default values (-b 5 -a 5 -ne)
       to avoid that logging itself continuously  causes  logging  of  further
       suspicious iterations.

       dpif-netdev/pmd-rxq-show [-pmd core] [dp]
              For  one  or all pmd threads of the datapath dp show the list of
              queue-ids with port names, which this thread polls.

       dpif-netdev/pmd-rxq-rebalance [dp]
              Reassigns rxqs to pmds in the datapath dp based on their current
              usage.

       dpif-netdev/bond-show [dp]
              When  "other_config:lb-output-action"  is  set  to  "true",  the
              userspace datapath handles the load balancing of bonds  directly
              instead  of depending on flow recirculation (only in balance-tcp
              mode).

              When this is the case, the above command prints the load-balanc‐
              ing  information  of the bonds configured in datapath dp showing
              the interface associated with each bucket (hash).

   NETDEV-DPDK COMMANDS
       These commands manage DPDK related ports (type=dpdk*).

       netdev-dpdk/set-admin-state [interface] up | down
              Change the admin state for DPDK interface to  up  or  down.   If
              interface is not specified, then it applies to all DPDK ports.

       netdev-dpdk/detach pci-address
              Detaches  device with corresponding pci-address from DPDK.  This
              command can be used to detach device if it wasn't detached auto‐
              matically  after  port  deletion. Refer to the documentation for
              details and instructions.

       netdev-dpdk/get-mempool-info [interface]
              Prints the debug information about  memory  pool  used  by  DPDK
              interface.   If called without arguments, information of all the
              available mempools will be printed. For additional mempool  sta‐
              tistics  enable  CONFIG_RTE_LIBRTE_MEMPOOL_DEBUG  while building
              DPDK.

   DATAPATH DEBUGGING COMMANDS
       These commands query and modify datapaths.  They  are  are  similar  to
       ovs-dpctl(8)  commands.   dpif/show  has  the additional functionality,
       beyond dpctl/show of printing OpenFlow port numbers.   The  other  com‐
       mands are redundant and will be removed in a future release.

       dpif/dump-dps
              Prints the name of each configured datapath on a separate line.

       dpif/show
              Prints  a  summary of configured datapaths, including statistics
              and a list of connected ports.  The  port  information  includes
              the  OpenFlow  port  number, datapath port number, and the type.
              (The local port is identified as OpenFlow port 65534.)

       dpif/dump-flows [-m] dp
              Prints to the console all flow entries in datapath dp's flow ta‐
              ble. Without -m, output omits match fields that a flow wildcards
              entirely; with -m output includes all wildcarded fields.

              This command is primarily useful  for  debugging  Open  vSwitch.
              The  flow  table  entries that it displays are not OpenFlow flow
              entries.  Instead, they are different and  considerably  simpler
              flows maintained by the datapath module.  If you wish to see the
              OpenFlow flow entries, use ovs-ofctl dump-flows.

       dpif/del-flows dp
              Deletes all flow entries  from  datapath  dp's  flow  table  and
              underlying  datapath  implementation (e.g., kernel datapath mod‐
              ule).

              This command is primarily useful for debugging Open vSwitch.  As
              discussed  in  dpif/dump-flows,  these  entries are not OpenFlow
              flow entries.

   OFPROTO COMMANDS
       These commands manage the core OpenFlow switch  implementation  (called
       ofproto).

       ofproto/list
              Lists the names of the running ofproto instances.  These are the
              names that may be used on ofproto/trace.

       ofproto/trace [options] [dpname] odp_flow [packet]
       ofproto/trace [options] bridge br_flow [packet]]
       ofproto/trace-packet-out [options] [dpname] odp_flow [packet] actions
       ofproto/trace-packet-out [options] bridge br_flow [packet] actions
              Traces the path  of  an  imaginary  packet  through  switch  and
              reports  the  path  that  it took.  The initial treatment of the
              packet varies based on the command:

              ·      ofproto/trace looks the packet up in  the  OpenFlow  flow
                     table, as if the packet had arrived on an OpenFlow port.

              ·      ofproto/trace-packet-out  applies  the specified OpenFlow
                     actions, as if the packet, flow,  and  actions  had  been
                     specified in an OpenFlow ``packet-out'' request.

              The  packet's headers (e.g. source and destination) and metadata
              (e.g. input port), together called its ``flow,'' are usually all
              that  matter for the purpose of tracing a packet.  You can spec‐
              ify the flow in the following ways:

              dpname odp_flow
                     odp_flow is a flow in the form printed by  ovs-dpctl(8)'s
                     dump-flows command.  If all of your bridges have the same
                     type, which is the common case, then you can omit dpname,
                     but  if  you  have  bridges of different types (say, both
                     ovs-netdev and ovs-system), then you need  to  specify  a
                     dpname to disambiguate.

              bridge br_flow
                     br_flow is a flow in the form similar to that accepted by
                     ovs-ofctl(8)'s add-flow command.  (This is not  an  Open‐
                     Flow  flow:  besides other differences, it never contains
                     wildcards.)  bridge names of  the  bridge  through  which
                     br_flow should be traced.

              These commands support the following options:

              --generate
                     Generate  a  packet  from  the  flow  (see below for more
                     information).

              --l7 payload
              --l7-len length
                     Accepted only with --generate (see below for more  infor‐
                     mation).

              --consistent
                     Accepted  by  ofproto-trace-packet-out  only.   With this
                     option, the command rejects actions that are inconsistent
                     with  the  specified packet.  (An example of an inconsis‐
                     tency is attempting to strip the VLAN tag from  a  packet
                     that  does  not  have  a VLAN tag.)  Open vSwitch ignores
                     most forms of inconsistency in OpenFlow 1.0  and  rejects
                     inconsistencies  in  later  versions  of  OpenFlow.   The
                     option is necessary because the command does not ordinar‐
                     ily  imply  a particular OpenFlow version.  One exception
                     is that, when actions includes an action that only  Open‐
                     Flow  1.1  and later supports (such as push_vlan), --con‐
                     sistent is automatically enabled.

              --ct-next flags
                     When  the  traced  flow   triggers   conntrack   actions,
                     ofproto/trace  will automatically trace the forked packet
                     processing pipeline with user specified  ct_state.   This
                     option  sets the ct_state flags that the conntrack module
                     will report. The flags must be a  comma-  or  space-sepa‐
                     rated list of the following connection tracking flags:

                     ·      trk:  Include  to indicate connection tracking has
                            taken place.

                     ·      new: Include to indicate a new flow.

                     ·      est: Include to indicate an established flow.

                     ·      rel: Include to indicate a related flow.

                     ·      rpl: Include to indicate a reply flow.

                     ·      inv: Include to indicate a connection entry  in  a
                            bad state.

                     ·      dnat:  Include to indicate a packet whose destina‐
                            tion IP address has been changed.

                     ·      snat: Include to indicate a packet whose source IP
                            address has been changed.

                     When  --ct-next  is  unspecified, or when there are fewer
                     --ct-next options than ct actions, the flags  default  to
                     trk,new.

              Most commonly, one specifies only a flow, using one of the forms
              above, but sometimes one might need to specify an actual  packet
              instead of just a flow:

              Side effects.
                     Some  actions have side effects.  For example, the normal
                     action can update the MAC learning table, and  the  learn
                     action  can  change  OpenFlow tables.  The trace commands
                     only perform side effects when a packet is specified.  If
                     you want side effects to take place, then you must supply
                     a packet.

                     (Output actions are obviously side effects too,  but  the
                     trace  commands  never execute them, even when one speci‐
                     fies a packet.)

              Incomplete information.
                     Most of the time, Open vSwitch can figure out  everything
                     about  the  path  of a packet using just the flow, but in
                     some special circumstances it needs to look at  parts  of
                     the  packet that are not included in the flow.  When this
                     is the case, and you do not supply a packet, then a trace
                     command will tell you it needs a packet.

              If  you  wish  to include a packet as part of a trace operation,
              there are two ways to do it:

              --generate
                     This option, added to one of the ways to specify  a  flow
                     already described, causes Open vSwitch to internally gen‐
                     erate a packet with the flow described and  then  to  use
                     that  packet.   If  your goal is to execute side effects,
                     then --generate is the easiest way to do it, but --gener‐
                     ate  is not a good way to fill in incomplete information,
                     because it generates  packets  based  on  only  the  flow
                     information,  which  means that the packets really do not
                     have any more information than the flow.

                     By default, for protocols that allow  arbitrary  L7  pay‐
                     loads, the generated packet has 64 bytes of payload.  Use
                     --l7-len to change the payload length, or --l7 to specify
                     the exact contents of the payload.

              packet This  form  supplies  an explicit packet as a sequence of
                     hex digits.  An Ethernet frame is at least 14 bytes long,
                     so  there  must be at least 28 hex digits.  Obviously, it
                     is inconvenient to type in the hex digits by hand, so the
                     ovs-pcap(1) and ovs-tcpundump(1) utilities provide easier
                     ways.

                     With this form, packet  headers  are  extracted  directly
                     from  packet,  so  the odp_flow or br_flow should specify
                     only metadata. The metadata can be:

                     skb_priority
                            Packet QoS priority.

                     pkt_mark
                            Mark of the packet.

                     ct_state
                            Connection state of the packet.

                     ct_zone
                            Connection tracking zone for packet.

                     ct_mark
                            Connection mark of the packet.

                     ct_label
                            Connection label of the packet.

                     tun_id The tunnel ID on which the packet arrived.

                     in_port
                            The port on which the packet arrived.

              The in_port value is kernel datapath port number for  the  first
              format  and OpenFlow port number for the second format. The num‐
              bering of these two types of port usually differs and  there  is
              no relationship.

       Usage examples:

           Trace an unicast ICMP echo request on ingress port 1 to destination
           MAC 00:00:5E:00:53:01
               ofproto/trace br in_port=1,icmp,icmp_type=8,\
               dl_dst=00:00:5E:00:53:01

           Trace an unicast ICMP echo reply on ingress port 1  to  destination
           MAC 00:00:5E:00:53:01
               ofproto/trace br in_port=1,icmp,icmp_type=0,\
               dl_dst=00:00:5E:00:53:01

           Trace an ARP request on ingress port 1
               ofproto/trace br in_port=1,arp,arp_op=1

           Trace an ARP reply on ingress port 1
               ofproto/trace br in_port=1,arp,arp_op=2

   VLOG COMMANDS
       These commands manage ovs-vswitchd's logging settings.

       vlog/set [spec]
              Sets  logging  levels.  Without any spec, sets the log level for
              every module and destination to dbg.  Otherwise, spec is a  list
              of words separated by spaces or commas or colons, up to one from
              each category below:

              ·      A valid module name, as displayed by the  vlog/list  com‐
                     mand on ovs-appctl(8), limits the log level change to the
                     specified module.

              ·      syslog, console, or file, to limit the log  level  change
                     to  only to the system log, to the console, or to a file,
                     respectively.

                     On Windows platform, syslog is accepted as a word and  is
                     only  useful  along  with the --syslog-target option (the
                     word has no effect otherwise).

              ·      off, emer, err, warn, info, or dbg, to  control  the  log
                     level.   Messages of the given severity or higher will be
                     logged, and messages of lower severity will  be  filtered
                     out.   off  filters  out all messages.  See ovs-appctl(8)
                     for a definition of each log level.

              Case is not significant within spec.

              Regardless of the log levels set for file,  logging  to  a  file
              will  not  take  place  unless ovs-vswitchd was invoked with the
              --log-file option.

              For compatibility with older versions of OVS, any is accepted as
              a word but has no effect.

       vlog/set PATTERN:destination:pattern
              Sets  the  log  pattern  for  destination  to pattern.  Refer to
              ovs-appctl(8) for a description of the valid syntax for pattern.

       vlog/list
              Lists the supported logging modules and their current levels.

       vlog/list-pattern
              Lists logging patterns used for each destination.

       vlog/close
              Causes ovs-vswitchd to close its log file, if it is open.   (Use
              vlog/reopen to reopen it later.)

       vlog/reopen
              Causes  ovs-vswitchd  to  close its log file, if it is open, and
              then reopen it.  (This is useful after rotating  log  files,  to
              cause a new log file to be used.)

              This  has  no  effect  unless  ovs-vswitchd was invoked with the
              --log-file option.

       vlog/disable-rate-limit [module]...
       vlog/enable-rate-limit [module]...
              By default, ovs-vswitchd limits the rate at which  certain  mes‐
              sages  can  be  logged.   When  a message would appear more fre‐
              quently than the limit,  it  is  suppressed.   This  saves  disk
              space,  makes  logs easier to read, and speeds up execution, but
              occasionally troubleshooting requires more  detail.   Therefore,
              vlog/disable-rate-limit allows rate limits to be disabled at the
              level of an individual log module.  Specify one or  more  module
              names, as displayed by the vlog/list command.  Specifying either
              no module names at all or the keyword any disables  rate  limits
              for every log module.

              The  vlog/enable-rate-limit command, whose syntax is the same as
              vlog/disable-rate-limit, can be used to re-enable a  rate  limit
              that was previously disabled.

   MEMORY COMMANDS
       These commands report memory usage.

       memory/show
              Displays  some  basic  statistics  about  ovs-vswitchd's  memory
              usage.  ovs-vswitchd  also  logs  this  information  soon  after
              startup and periodically as its memory consumption grows.

   COVERAGE COMMANDS
       These commands manage ovs-vswitchd's ``coverage counters,'' which count
       the number of times particular events occur during a daemon's  runtime.
       In addition to these commands, ovs-vswitchd automatically logs coverage
       counter values, at INFO level, when it detects that the  daemon's  main
       loop takes unusually long to run.

       Coverage counters are useful mainly for performance analysis and debug‐
       ging.

       coverage/show
              Displays the averaged per-second rates for the last few seconds,
              the  last  minute and the last hour, and the total counts of all
              of the coverage counters.

       coverage/read-counter counter
              Displays the total count for the given coverage counter.

   OPENVSWITCH TUNNELING COMMANDS
       These commands query and modify OVS tunnel components.

       ovs/route/add ipv4_address/plen output_bridge [GW]
              Adds ipv4_address/plen route to  vswitchd  routing  table.  out‐
              put_bridge  needs to be OVS bridge name.  This command is useful
              if OVS cached routes does not look right.

       ovs/route/show
              Print all routes in OVS  routing  table,  This  includes  routes
              cached from system routing table and user configured routes.

       ovs/route/del ipv4_address/plen
              Delete ipv4_address/plen route from OVS routing table.

       tnl/neigh/show

       tnl/arp/show
              OVS  builds  ARP  cache  by  snooping are messages. This command
              shows ARP cache table.

       tnl/neigh/set bridge ip mac

       tnl/arp/set bridge ip mac
              Adds or modifies an ARP cache entry in  bridge,  mapping  ip  to
              mac.

       tnl/neigh/flush

       tnl/arp/flush
              Flush ARP table.

       tnl/egress_port_range [num1] [num2]
              Set  range  for  UDP source port used for UDP based Tunnels. For
              example VxLAN. If case of zero  arguments  this  command  prints
              current range in use.

OPENFLOW IMPLEMENTATION
       This section documents aspects of OpenFlow for which the OpenFlow spec‐
       ification requires documentation.

   Packet buffering.
       The OpenFlow specification, version 1.2, says:

              Switches  that  implement  buffering  are  expected  to  expose,
              through  documentation,  both the amount of available buffering,
              and the length of time before buffers may be reused.

       Open vSwitch does not maintains any packet buffers.

   Bundle lifetime
       The OpenFlow specification, version 1.4, says:

              If the  switch  does  not  receive  any  OFPT_BUNDLE_CONTROL  or
              OFPT_BUNDLE_ADD_MESSAGE  message  for  an opened bundle_id for a
              switch  defined  time  greater  than  1s,   it   may   send   an
              ofp_error_msg  with  OFPET_BUNDLE_FAILED type and OFPBFC_TIMEOUT
              code.  If the switch does not receive any new message in a  bun‐
              dle  apart  from  echo  request and replies for a switch defined
              time  greater  than  1s,  it  may  send  an  ofp_error_msg  with
              OFPET_BUNDLE_FAILED type and OFPBFC_TIMEOUT code.

       Open  vSwitch  implements  default  idle bundle lifetime of 10 seconds.
       (This  is  configurable  via  other-config:bundle-idle-timeout  in  the
       Open_vSwitch table. See ovs-vswitchd.conf.db(5) for details.)

LIMITS
       We  believe these limits to be accurate as of this writing.  These lim‐
       its assume the use of the Linux kernel datapath.

       ·      ovs-vswitchd started through  ovs-ctl(8)  provides  a  limit  of
              65535 file descriptors.  The limits on the number of bridges and
              ports is decided by the availability of file descriptors.   With
              the  Linux kernel datapath, creation of a single bridge consumes
              three file descriptors and each  port  consumes  one  additional
              file  descriptor.   Other  platforms  may have different limita‐
              tions.

       ·      8,192 MAC learning entries per bridge,  by  default.   (This  is
              configurable  via  other-config:mac-table-size in the Bridge ta‐
              ble.  See ovs-vswitchd.conf.db(5) for details.)

       ·      Kernel flows are limited only by memory available to the kernel.
              Performance  will  degrade  beyond  1,048,576  kernel  flows per
              bridge with a 32-bit kernel, beyond 262,144 with a  64-bit  ker‐
              nel.  (ovs-vswitchd should never install anywhere near that many
              flows.)

       ·      OpenFlow flows are limited only by  available  memory.   Perfor‐
              mance is linear in the number of unique wildcard patterns.  That
              is, an OpenFlow table that contains many flows that all match on
              the  same fields in the same way has a constant-time lookup, but
              a table that contains many flows that match on different  fields
              requires lookup time linear in the number of flows.

       ·      255  ports per bridge participating in 802.1D Spanning Tree Pro‐
              tocol.

       ·      32 mirrors per bridge.

       ·      15 bytes for the name of a port, for ports  implemented  in  the
              Linux  kernel.   Ports  implemented  in userspace, such as patch
              ports, do not have an  arbitrary  length  limitation.   OpenFlow
              also limit port names to 15 bytes.

SEE ALSO
       ovs-appctl(8), ovsdb-server(1).



Open vSwitch                        2.15.90                    ovs-vswitchd(8)