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
                     itself. 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
         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 : dpdk-init    optional string, either true or false
         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-hugepage-dir
                                     optional string
         other_config : dpdk-extra   optional string
         other_config : vhost-sock-dir
                                     optional string
         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
       Status:
         next_cfg                    integer
         cur_cfg                     integer
         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
       Capabilities:
         datapath_types              set of strings
         iface_types                 set of strings
       Database Configuration:
         manager_options             set of Managers
       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.

       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.

              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 con‐
                troller) to restore the OpenFlow flow  table  to  the  desired
                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 : dpdk-init: optional string, either true or false
              Set this value to true to enable runtime support for DPDK ports.
              The vswitch must have compile-time support for DPDK as well.

              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
              default.

       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.

              If  not  specified, the value is 0. Changing this value requires
              restarting the daemon.

       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 (ex: 1024,2048,4096,8192 would set socket 0 to preal‐
              locate 1024MB, socket 1 to preallocate 2048MB, etc.)

              If  not  specified,  the  default value is 1024,0. 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
              (default   is  /dev/hugepages).  Changing  this  value  requires
              restarting 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  the  path to the vhost-user unix domain socket files.
              This path must exist and be a  subdirectory  tree  of  the  Open
              vSwitch run directory.

              Defaults  to  the working directory of the application. Changing
              this value requires restarting the daemon.

       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.

     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.

     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  nec‐
                essarily 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
              always 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.

     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 connection should be configured. See  the  Manager
              table for more information.

     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 OpenFlow11, Open
                                     Flow10,  OpenFlow13,  OpenFlow12,   Open
                                     Flow15, OpenFlow14, 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,
              interfaces, 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
              Interface 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
              incompatible  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 flow table. If there are no primary controllers, adding  one
              also  clears  the  flow  table. Other changes to the set of con‐
              trollers, such as  adding  or  removing  a  service  controller,
              adding another primary controller to supplement an existing pri‐
              mary controller, or  removing  only  one  of  two  primary  con‐
              trollers, have no effect on the flow table.

       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
              determines  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 flow 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
              Exactly  16 hex digits to set the OpenFlow datapath ID to a spe‐
              cific value. May not be all-zero.

       other_config : dp-desc: optional string
              Human readable description of datapath.  It  it  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
              instead.

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

              OpenFlow 1.4, 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
              delay 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
              entry 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
              unset, 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
                     received 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 2048. 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,
                                     native-tagged, native-untagged, 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
         other_config : priority-tags
                                     optional string, either true or false
       Bonding Configuration:
         bond_mode                   optional  string,  one  of active-backup,
                                     balance-tcp, or balance-slb
         other_config : bond-hash-basis
                                     optional string, containing an integer
         Link Failure Detection:
            other_config : bond-detect-mode
                                     optional string, either miimon or carrier
            other_config : bond-miimon-interval
                                     optional string, containing an integer
            bond_updelay             integer
            bond_downdelay           integer
         LACP Configuration:
            lacp                     optional string, one of active,  passive,
                                     or off
            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 slow or fast
            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  disabled,  for
                                     warding, learning, listening, or blocking
            status : stp_sec_in_state
                                     optional  string,  containing an integer,
                                     at least 0
            status : stp_role        optional  string,  one   of   designated,
                                     alternate, 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 Backup, Desig
                                     nated, Alternate, Root, or Disabled
            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:

       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
                     exception  that  a  packet  without an 802.1Q header that
                     ingresses 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
                     native-untagged  port in the native VLAN will not have an
                     802.1Q header.

       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,   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
              native-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.

       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
              default Open vSwitch does  not  output  priority-tagged  frames,
              instead  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 L2, L3, and L4 pro‐
                     tocol information such as  destination  MAC  address,  IP
                     address, and TCP port.

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

       bond_mode: optional string, one of active-backup, balance-tcp, or  bal
       ance-slb
              The  type  of  bonding  used  for  a  bonded  port.  Defaults to
              active-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 miimon or car
       rier
              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
       integer
              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, passive, or off
              Configures LACP on this port.  LACP  allows  directly  connected
              switches  to  negotiate  which  links may be bonded. LACP may be
              enabled 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
       integer, 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 slow or fast
              The LACP timing which should be used on this  Port.  By  default
              slow  is  used.  When  configured to be fast LACP heartbeats are
              requested at a rate of  once  per  second  causing  connectivity
              problems  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
              option  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
              between successive attempts to rebalance the bond, that  is,  to
              move  flows  from  one  interface  on  the bond to another in an
              attempt 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
              default, 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  disabled,  forwarding,
       learning, listening, or blocking
              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 designated, alternate, 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
       enabled 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
       integer
              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 Backup, Desig
       nated, Alternate, Root, or Disabled
              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
              reflect  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
              library.

       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 : 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: vxlan only:
            options : exts           optional string
         Tunnel Options: gre, geneve, and vxlan:
            options : csum           optional string, either true or false
       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 : 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
       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
       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 Status:
            bfd_status : state       optional  string,  one of down, init, up,
                                     or admin_down
            bfd_status : forwarding  optional string, either true or false
            bfd_status : diagnostic  optional string
            bfd_status : remote_state
                                     optional string, one of down,  init,  up,
                                     or admin_down
            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
       Rx Checksum Offload Configuration:
         options : rx-checksum-offload
                                     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
              address.

       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
       obtained,  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.

              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    An  Ethernet  over RFC 2890 Generic Routing Encapsulation
                     over IPv4/IPv6 tunnel.

              vxlan  An Ethernet tunnel  over  the  UDP-based  VXLAN  protocol
                     described 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
                     inside  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.

              null   An ignored interface. Deprecated and slated  for  removal
                     in February 2013.

     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,
       options: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-ofctl  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-ofctl manual  page  contains  additional  information
                     about the Nicira OpenFlow vendor extensions.

       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
              default 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
              enabled; 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: 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)

     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.

     Patch Options:

       Only patch interfaces support these options.

       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_gt;gt; where
              ’driver_name’ is a valid virtual DPDK PMD driver name and  where
              ’x’ lies in the range of 0 to RTE_MAX_ETHPORTS-1. Only supported
              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  : 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.

     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
       interfaces 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
              interface  which is responsible for routing traffic destined for
              the configured options:remote_ip.  This  could  be  an  internal
              interface 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.

     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
       periodic 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
       implementations 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
                     tokens)  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
                     tokens 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
              default) 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. Open  vSwitch  uses  a  detection
       multiplier  of  three,  meaning that an endpoint signals a connectivity
       fault if three consecutive BFD control messages fail to arrive. 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
       Authentication 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
              incoming 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
              default 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
              address 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 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:enable, the switch clears all key-value pairs from bfd_status.

       bfd_status  :  state:  optional  string,  one  of  down,  init,  up, or
       admin_down
              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 down, init,  up,  or
       admin_down
              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
              between  [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
              receive  heartbeats  from  any  remote endpoint. When a fault is
              triggered on Interfaces participating in  bonds,  they  will  be
              disabled.

              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.
              Notably,  this  case  arises when a CCM is received which adver‐
              tises the local MPID.

       cfm_fault_status : recv: none
              Indicates a CFM fault was  triggered  due  to  a  lack  of  CCMs
              received 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
              received  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_con
              fig:cfm_opstate.

       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
              refreshed.

              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
              Interface  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
              every 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
              Interface on which this CFM module  is  running.  Currently,  in
              Open vSwitch, the opdown bit of CCMs affects Interfaces partici‐
              pating in bonds, and the bundle OpenFlow action. This setting is
              ignored 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
       integer, 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
              instance  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 pur‐
              poses). During such a ``migration,’’ two instances of  a  single
              external_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
              default, 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
              default, 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.

     Rx Checksum Offload Configuration:

       The  checksum  validation  on the incoming packets are performed on NIC
       using Rx checksum offload feature. Implemented only for  dpdk  physical
       interfaces.

       options : rx-checksum-offload: optional string, either true or false
              Set  to  false  to disble Rx checksum offloading on dpdkphysical
              ports. By default, Rx checksum offload is enabled.

     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 refuse or evict
         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
       installed 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  values
                of  the fields or subfields specified in the groups column, 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 integer
                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 refuse or evict
              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
              address 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
                     address 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
       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
              assuming  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.

     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
              receives  any.  Specific  priority  values are unimportant; only
              relative 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
       becomes  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
       before  the first output that makes it eligible for mirroring to a par‐
       ticular 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
       select_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
       selected VLANs.

       select_all: boolean
              If true, every packet arriving  or  departing  on  any  port  is
              selected 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
              Interface table for a list of destination  MAC  addresses  which
              will  not be mirrored to a VLAN to avoid confusing switches that
              interpret 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
              intermediate switch, learning can be disabled by adding the mir‐
              rored  VLAN  to  flood_vlans  in the appropriate Bridge table or
              tables.

              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
                     intended 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 slave, other,  or
                                     master
         status : last_error         optional string
         status : state              optional  string,  one  of  ACTIVE, VOID,
                                     CONNECTING, IDLE, or BACKOFF
         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:ip[:port]
                     The specified SSL port on the host at the given ip, which
                     must be expressed as an IP address (not a DNS name).  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 6653.

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

              tcp:ip[:port]
                     The specified TCP port on the host at the given ip, which
                     must be expressed as an IP  address  (not  a  DNS  name),
                     where  ip  can  be IPv4 or IPv6 address. If ip 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][:ip]
                     Listens for SSL connections on the specified TCP port. If
                     ip, which must be expressed as an IP address (not  a  DNS
                     name),  is  specified, then connections are restricted to
                     the specified local IP address (either IPv4 or IPv6).  If
                     ip  is  an IPv6 address, wrap it in square brackets, e.g.
                     pssl:6653:[::1].

                     If port is not specified, it defaults to 6653. If  ip  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][:ip]
                     Listens for connections on the specified TCP port. If ip,
                     which must be expressed as  an  IP  address  (not  a  DNS
                     name),  is  specified, then connections are restricted to
                     the specified local IP address (either IPv4 or IPv6).  If
                     ip  is  an IPv6 address, wrap it in square brackets, e.g.
                     ptcp:6653:[::1]. If ip 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
              attempts. 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
              receive 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
       enabled.

       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
              increase 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 slave, other, or master
              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, VOID, CONNECTING, IDLE,
       or BACKOFF
              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
              default  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,  VOID,
                                     CONNECTING, IDLE, or BACKOFF
         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:ip[:port]
                     The specified SSL port on the host at the given ip, which
                     must  be expressed as an IP address (not a DNS name). 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.

              tcp:ip[:port]
                     The specified TCP port on the host at the given ip, which
                     must  be  expressed  as  an  IP address (not a DNS name),
                     where ip can be IPv4 or IPv6 address. If ip  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][:ip]
                     Listens  for  SSL  connections on the specified TCP port.
                     Specify 0 for  port  to  have  the  kernel  automatically
                     choose  an available port. If ip, which must be expressed
                     as an IP address (not a DNS  name),  is  specified,  then
                     connections  are  restricted  to  the  specified local IP
                     address (either IPv4 or IPv6 address). If ip is  an  IPv6
                     address,  wrap  in square brackets, e.g. pssl:6640:[::1].
                     If ip 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 defaults to 6640.

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

              ptcp:[port][:ip]
                     Listens for connections on the specified TCP port.  Spec‐
                     ify 0 for port to have the kernel automatically choose an
                     available port. If ip, which must be expressed as  an  IP
                     address  (not a DNS name), is specified, then connections
                     are restricted to the specified local IP address  (either
                     IPv4  or IPv6 address). If ip is an IPv6 address, wrap it
                     in square brackets, e.g. ptcp:6640:[::1]. If  ip  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
              attempts. 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, VOID, CONNECTING, IDLE,
       or BACKOFF
              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
              inbound 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
              default 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
       details 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
              index 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
              immediately  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
              Name of the network device whose IP address should  be  reported
              as  the  ``agent  address’’ to collectors. 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  col‐
              lector’s Controller. If an agent IP address cannot be determined
              any of these ways, 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-ofctl(8) 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,
              defaults 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-tuples  in  IPFIX  flow records. Tunnel sampling is enabled by
              default.

              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
                     respective 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
                     locally 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
       advantage 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 2.7.90             DB Schema 7.14.0       ovs-vswitchd.conf.db(5)