ovn-sb(5)                     Open vSwitch Manual                    ovn-sb(5)

NAME
       ovn-sb - OVN_Southbound database schema

       This  database  holds  logical and physical configuration and state for
       the Open Virtual Network (OVN) system to support  virtual  network  ab‐
       straction. For an introduction to OVN, please see ovn-architecture(7).

       The OVN Southbound database sits at the center of the OVN architecture.
       It is the one component that speaks both southbound directly to all the
       hypervisors  and  gateways, via ovn-controller/ovn-controller-vtep, and
       northbound to the Cloud Management System, via ovn-northd:

   Database Structure
       The OVN Southbound database contains classes  of  data  with  different
       properties, as described in the sections below.

     Physical network

       Physical  network tables contain information about the chassis nodes in
       the system. This contains all the information  necessary  to  wire  the
       overlay,  such  as  IP  addresses, supported tunnel types, and security
       keys.

       The amount of physical network data is small (O(n)  in  the  number  of
       chassis)  and it changes infrequently, so it can be replicated to every
       chassis.

       The Chassis and Encap tables are the physical network tables.

     Logical Network

       Logical network tables contain the topology  of  logical  switches  and
       routers,  ACLs,  firewall  rules, and everything needed to describe how
       packets traverse a logical network,  represented  as  logical  datapath
       flows (see Logical Datapath Flows, below).

       Logical network data may be large (O(n) in the number of logical ports,
       ACL rules, etc.). Thus, to improve scaling, each chassis should receive
       only  data  related  to logical networks in which that chassis partici‐
       pates.

       The logical network data is ultimately controlled by the cloud  manage‐
       ment  system  (CMS)  running northbound of OVN. That CMS determines the
       entire OVN logical configuration and therefore the logical network data
       at any given time is a deterministic function of the  CMS’s  configura‐
       tion,  although that happens indirectly via the OVN_Northbound database
       and ovn-northd.

       Logical network data is likely to change  more  quickly  than  physical
       network  data. This is especially true in a container environment where
       containers are created  and  destroyed  (and  therefore  added  to  and
       deleted from logical switches) quickly.

       The   Logical_Flow,   Multicast_Group,   Address_Group,   DHCP_Options,
       DHCPv6_Options, and DNS tables contain logical network data.

     Logical-physical bindings

       These tables link logical and physical components. They show  the  cur‐
       rent  placement of logical components (such as VMs and VIFs) onto chas‐
       sis, and map logical entities to the values that represent them in tun‐
       nel encapsulations.

       These tables change frequently, at least every time a VM powers  up  or
       down  or  migrates,  and especially quickly in a container environment.
       The amount of data per VM (or VIF) is small.

       Each chassis is authoritative about the VMs and VIFs that it  hosts  at
       any  given time and can efficiently flood that state to a central loca‐
       tion, so the consistency needs are minimal.

       The Port_Binding and Datapath_Binding tables contain binding data.

     MAC bindings

       The MAC_Binding table tracks the bindings from IP addresses to Ethernet
       addresses that are dynamically discovered  using  ARP  (for  IPv4)  and
       neighbor  discovery (for IPv6). Usually, IP-to-MAC bindings for virtual
       machines are statically  populated  into  the  Port_Binding  table,  so
       MAC_Binding  is  primarily  used  to discover bindings on physical net‐
       works.

   Common Columns
       Some tables contain a special column named  external_ids.  This  column
       has  the  same  form  and purpose each place that it appears, so we de‐
       scribe it here to save space later.

              external_ids: map of string-string pairs
                     Key-value pairs for use by the software that manages  the
                     OVN   Southbound   database   rather   than  by  ovn-con‐‐
                     troller/ovn-controller-vtep.  In  particular,  ovn-northd
                     can use key-value pairs in this column to relate entities
                     in the southbound database to higher-level entities (such
                     as  entities  in the OVN Northbound database). Individual
                     key-value pairs in this column may be documented in  some
                     cases  to  aid  in understanding and troubleshooting, but
                     the reader should not mistake such documentation as  com‐
                     prehensive.

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

       Table     Purpose
       SB_Global Southbound configuration
       Chassis   Physical Network Hypervisor and Gateway Information
       Chassis_Private
                 Chassis Private
       Encap     Encapsulation Types
       Address_Set
                 Address Sets
       Port_Group
                 Port Groups
       Logical_Flow
                 Logical Network Flows
       Logical_DP_Group
                 Logical Datapath Groups
       Multicast_Group
                 Logical Port Multicast Groups
       Mirror    Mirror Entry
       Meter     Meter entry
       Meter_Band
                 Band for meter entries
       Datapath_Binding
                 Physical-Logical Datapath Bindings
       Port_Binding
                 Physical-Logical Port Bindings
       MAC_Binding
                 IP to MAC bindings
       DHCP_Options
                 DHCP Options supported by native OVN DHCP
       DHCPv6_Options
                 DHCPv6 Options supported by native OVN DHCPv6
       Connection
                 OVSDB client connections.
       SSL       SSL configuration.
       DNS       Native DNS resolution
       RBAC_Role RBAC_Role configuration.
       RBAC_Permission
                 RBAC_Permission configuration.
       Gateway_Chassis
                 Gateway_Chassis configuration.
       HA_Chassis
                 HA_Chassis configuration.
       HA_Chassis_Group
                 HA_Chassis_Group configuration.
       Controller_Event
                 Controller Event table
       IP_Multicast
                 IP_Multicast configuration.
       IGMP_Group
                 IGMP_Group configuration.
       Service_Monitor
                 Service_Monitor configuration.
       Load_Balancer
                 Load_Balancer configuration.
       BFD       BFD configuration.
       FDB       Port to MAC bindings
       Static_MAC_Binding
                 IP to MAC bindings
       Chassis_Template_Var
                 Chassis_Template_Var configuration.

SB_Global TABLE
       Southbound  configuration  for  an OVN system. This table must have ex‐
       actly one row.

   Summary:
       Status:
         nb_cfg                      integer
       Common Columns:
         external_ids                map of string-string pairs
         options                     map of string-string pairs
       Common options:
         options                     map of string-string pairs
         Options for configuring BFD:
            options : bfd-min-rx     optional string
            options : bfd-decay-min-rx
                                     optional string
            options : bfd-min-tx     optional string
            options : bfd-mult       optional string
            options : debug_drop_domain_id
                                     optional string
            options : debug_drop_collector_set
                                     optional string
         Options for configuring ovn-sbctl:
            options : sbctl_probe_interval
                                     optional string
       Connection Options:
         connections                 set of Connections
         ssl                         optional SSL
       Security Configurations:
         ipsec                       boolean

   Details:
     Status:

       This column allow a client to track the overall configuration state  of
       the system.

       nb_cfg: integer
              Sequence  number  for the configuration. When a CMS or ovn-nbctl
              updates the northbound database, it increments the nb_cfg column
              in the NB_Global table in the northbound database. In turn, when
              ovn-northd updates the southbound database to  bring  it  up  to
              date  with  these  changes,  it  updates this column to the same
              value.

     Common Columns:

       external_ids: map of string-string pairs
              See External IDs at the beginning of this document.

       options: map of string-string pairs

     Common options:

       options: map of string-string pairs
              This column provides general key/value settings.  The  supported
              options are described individually below.

     Options for configuring BFD:

       These  options  apply when ovn-controller configures BFD on tunnels in‐
       terfaces.

       options : bfd-min-rx: optional string
              BFD option min-rx value to use when configuring  BFD  on  tunnel
              interfaces.

       options : bfd-decay-min-rx: optional string
              BFD  option  decay-min-rx  value  to use when configuring BFD on
              tunnel interfaces.

       options : bfd-min-tx: optional string
              BFD option min-tx value to use when configuring  BFD  on  tunnel
              interfaces.

       options : bfd-mult: optional string
              BFD  option mult value to use when configuring BFD on tunnel in‐
              terfaces.

       options : debug_drop_domain_id: optional string
              If set to a 8-bit number and if debug_drop_collector_set is also
              configured, ovn-controller will add a  sample  action  to  every
              flow  that  does  not  come  from a logical flow that contains a
              ’drop’ action. The 8  most  significant  bits  of  the  observa‐
              tion_domain_id  field  will  be  those  specified  in  the   de‐‐
              bug_drop_domain_id. The 24 least significant bits of the  obser‐
              vation_domain_id field will be zero.

              The  observation_point_id will be set to the OpenFlow table num‐
              ber.

       options : debug_drop_collector_set: optional string
              If set to a 32-bit number ovn-controller will add a  sample  ac‐
              tion  to  every flow that does not come from a logical flow that
              contains a ’drop’ action. The sample action will have the speci‐
              fied collector_set_id. The value must match that  of  the  local
              OVS configuration as described in ovs-actions(7).

     Options for configuring ovn-sbctl:

       These options apply when ovn-sbctl connects to OVN Southbound database.

       options : sbctl_probe_interval: optional string
              The  inactivity  probe  interval  of  the  connection to the OVN
              Southbound database from ovn-sbctl utility, in milliseconds.  If
              the value is zero, it disables the connection keepalive feature.

              If the value is nonzero, then it will be forced to a value of at
              least 1000 ms.

              If  the  value  is  less  than zero, then the default inactivity
              probe interval for ovn-sbctl would be left intact (120000 ms).

     Connection Options:

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

       ssl: optional SSL
              Global SSL configuration.

     Security Configurations:

       ipsec: boolean
              Tunnel  encryption  configuration.  If  this column is set to be
              true, all OVN tunnels will be encrypted with IPsec.

Chassis TABLE
       Each row in this table represents a hypervisor or gateway  (a  chassis)
       in  the  physical  network.  Each  chassis, via ovn-controller/ovn-con‐‐
       troller-vtep, adds and updates its own row, and keeps a copy of the re‐
       maining rows to determine how to reach other hypervisors.

       When a chassis shuts down gracefully, it should  remove  its  own  row.
       (This  is  not  critical  because  resources  hosted on the chassis are
       equally unreachable regardless of whether the row  is  present.)  If  a
       chassis  shuts  down permanently without removing its row, some kind of
       manual or automatic cleanup is  eventually  needed;  we  can  devise  a
       process for that as necessary.

   Summary:
       name                          string (must be unique within table)
       hostname                      string
       nb_cfg                        integer
       other_config : ovn-bridge-mappings
                                     optional string
       other_config : datapath-type  optional string
       other_config : iface-types    optional string
       other_config : ovn-cms-options
                                     optional string
       other_config : is-interconn   optional string
       other_config : is-remote      optional string
       transport_zones               set of strings
       other_config : ovn-chassis-mac-mappings
                                     optional string
       other_config : port-up-notif  optional string
       Common Columns:
         external_ids                map of string-string pairs
       Encapsulation Configuration:
         encaps                      set of 1 or more Encaps
       Gateway Configuration:
         vtep_logical_switches       set of strings

   Details:
       name: string (must be unique within table)
              OVN  does  not  prescribe a particular format for chassis names.
              ovn-controller populates this column using  external_ids:system-
              id  in  the Open_vSwitch database’s Open_vSwitch table. ovn-con‐
              troller-vtep populates  this  column  with  name  in  the  hard‐
              ware_vtep database’s Physical_Switch table.

       hostname: string
              The  hostname of the chassis, if applicable. ovn-controller will
              populate this column with the hostname of the host it is running
              on. ovn-controller-vtep will leave this column empty.

       nb_cfg: integer
              Deprecated. This column is replaced by the nb_cfg column of  the
              Chassis_Private table.

       other_config : ovn-bridge-mappings: optional string
              ovn-controller  populates  this  key with the set of bridge map‐
              pings it has been configured to use. Other  applications  should
              treat  this key as read-only. See ovn-controller(8) for more in‐
              formation.

       other_config : datapath-type: optional string
              ovn-controller populates this key with the datapath type config‐
              ured in the datapath_type column of the Open_vSwitch  database’s
              Bridge  table. Other applications should treat this key as read-
              only. See ovn-controller(8) for more information.

       other_config : iface-types: optional string
              ovn-controller populates this key with the interface types  con‐
              figured in the iface_types column of the Open_vSwitch database’s
              Open_vSwitch  table. Other applications should treat this key as
              read-only. See ovn-controller(8) for more information.

       other_config : ovn-cms-options: optional string
              ovn-controller populates this key with the set of  options  con‐
              figured   in  the  external_ids:ovn-cms-options  column  of  the
              Open_vSwitch  database’s  Open_vSwitch   table.   See   ovn-con‐‐
              troller(8) for more information.

       other_config : is-interconn: optional string
              ovn-controller populates this key with the setting configured in
              the  external_ids:ovn-is-interconn  column  of  the Open_vSwitch
              database’s Open_vSwitch table. If set to true,  the  chassis  is
              used  as  an  interconnection gateway. See ovn-controller(8) for
              more information.

       other_config : is-remote: optional string
              ovn-ic set this key to true for remote  interconnection  gateway
              chassises  learned from the interconnection southbound database.
              See ovn-ic(8) for more information.

       transport_zones: set of strings
              ovn-controller populates this key with the transport zones  con‐
              figured  in  the  external_ids:ovn-transport-zones column of the
              Open_vSwitch  database’s  Open_vSwitch   table.   See   ovn-con‐‐
              troller(8) for more information.

       other_config : ovn-chassis-mac-mappings: optional string
              ovn-controller  populates  this key with the set of options con‐
              figured in the external_ids:ovn-chassis-mac-mappings  column  of
              the  Open_vSwitch  database’s  Open_vSwitch  table. See ovn-con‐‐
              troller(8) for more information.

       other_config : port-up-notif: optional string
              ovn-controller populates this key with  true  when  it  supports
              Port_Binding.up.

     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

     Encapsulation Configuration:

       OVN uses encapsulation to transmit logical  dataplane  packets  between
       chassis.

       encaps: set of 1 or more Encaps
              Points  to  supported  encapsulation  configurations to transmit
              logical dataplane packets to this chassis. Each entry is a Encap
              record that describes the configuration.

     Gateway Configuration:

       A gateway is a chassis that forwards traffic  between  the  OVN-managed
       part of a logical network and a physical VLAN, extending a tunnel-based
       logical  network  into a physical network. Gateways are typically dedi‐
       cated nodes that do not host VMs and will  be  controlled  by  ovn-con‐‐
       troller-vtep.

       vtep_logical_switches: set of strings
              Stores  all  VTEP logical switch names connected by this gateway
              chassis. The Port_Binding table entry  with  options:vtep-physi‐‐
              cal-switch  equal  Chassis name, and options:vtep-logical-switch
              value in Chassis vtep_logical_switches, will be associated  with
              this Chassis.

Chassis_Private TABLE
       Each  row in this table maintains per chassis private data that are ac‐
       cessed only by the owning chassis (write only) and ovn-northd,  not  by
       any other chassis. These data are stored in this separate table instead
       of  the  Chassis table for performance considerations: the rows in this
       table can be conditionally monitored by chassises so that each  chassis
       only  get  update  notifications  for its own row, to avoid unnecessary
       chassis private data update flooding in a large scale deployment.

   Summary:
       name                          string (must be unique within table)
       chassis                       optional weak reference to Chassis
       nb_cfg                        integer
       nb_cfg_timestamp              integer
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       name: string (must be unique within table)
              The name of the chassis that owns these chassis-private data.

       chassis: optional weak reference to Chassis
              The reference to Chassis table for the chassis that  owns  these
              chassis-private data.

       nb_cfg: integer
              Sequence  number  for the configuration. When ovn-controller up‐
              dates the configuration of a chassis from the  contents  of  the
              southbound  database,  it copies nb_cfg from the SB_Global table
              into this column.

       nb_cfg_timestamp: integer
              The timestamp when ovn-controller finishes processing the change
              corresponding to nb_cfg.

     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
Encap TABLE
       The  encaps column in the Chassis table refers to rows in this table to
       identify how OVN may transmit logical dataplane packets to  this  chas‐
       sis.  Each  chassis,  via  ovn-controller(8) or ovn-controller-vtep(8),
       adds and updates its own rows and keeps a copy of the remaining rows to
       determine how to reach other chassis.

   Summary:
       type                          string, one of geneve, stt, or vxlan
       options                       map of string-string pairs
       options : csum                optional string, either true or false
       options : dst_port            optional string, containing an integer
       options : is_default          optional string, either true or false
       ip                            string
       chassis_name                  string

   Details:
       type: string, one of geneve, stt, or vxlan
              The encapsulation to use to transmit packets  to  this  chassis.
              Hypervisors and gateways must use one of: geneve, vxlan, or stt.

       options: map of string-string pairs
              Options  for  configuring  the  encapsulation, which may be type
              specific.

       options : csum: optional string, either true or false
              csum indicates whether this chassis  can  transmit  and  receive
              packets  that  include checksums with reasonable performance. It
              hints to senders transmitting data to  this  chassis  that  they
              should  use  checksums  to  protect OVN metadata. ovn-controller
              populates this key with the value defined  in  external_ids:ovn-
              encap-csum  column  of  the Open_vSwitch database’s Open_vSwitch
              table. Other applications should treat this  key  as  read-only.
              See ovn-controller(8) for more information.

              In terms of performance, checksumming actually significantly in‐
              creases  throughput  in  most common cases when running on Linux
              based hosts without NICs supporting encapsulation  hardware  of‐
              fload  (around  60% for bulk traffic). The reason is that gener‐
              ally all NICs are capable of offloading transmitted and received
              TCP/UDP checksums (viewed as ordinary data packets  and  not  as
              tunnels).  The benefit comes on the receive side where the vali‐
              dated outer checksum can be used to additionally validate an in‐
              ner checksum (such as TCP), which in turn allows aggregation  of
              packets to be more efficiently handled by the rest of the stack.

              Not  all  devices see such a benefit. The most notable exception
              is hardware VTEPs. These devices are designed to not buffer  en‐
              tire packets in their switching engines and are therefore unable
              to efficiently compute or validate full packet checksums. In ad‐
              dition  certain  versions  of  the  Linux kernel are not able to
              fully take advantage of encapsulation NIC offloads in the  pres‐
              ence of checksums. (This is actually a pretty narrow corner case
              though:  earlier  versions  of Linux don’t support encapsulation
              offloads at all and later versions  support  both  offloads  and
              checksums well.)

              csum defaults to false for hardware VTEPs and true for all other
              cases.

              This option applies to geneve and vxlan encapsulations.

       options : dst_port: optional string, containing an integer
              If  set,  overrides  the  UDP (for geneve and vxlan) or TCP (for
              stt) destination port.

       options : is_default: optional string, either true or false
              When there are multiple encaps for a chassis with different IPs,
              this option indicates if the  encap  is  the  default  one  that
              matches  the  IP  in external_ids:ovn-encap-ip-default column of
              the Open_vSwitch database’s Open_vSwitch table.

       ip: string
              The IPv4 address of the encapsulation tunnel endpoint.

       chassis_name: string
              The name of the chassis that created this encap.

Address_Set TABLE
       This table contains address sets synced from the Address_Set  table  in
       the  OVN_Northbound  database  and  address  sets  generated  from  the
       Port_Group table in the OVN_Northbound database.

       See the documentation for the Address_Set table and Port_Group table in
       the OVN_Northbound database for details.

   Summary:
       name                          string (must be unique within table)
       addresses                     set of strings

   Details:
       name: string (must be unique within table)

       addresses: set of strings
Port_Group TABLE
       This  table  contains  names  for  the  logical  switch  ports  in  the
       OVN_Northbound  database that belongs to the same group that is defined
       in Port_Group in the OVN_Northbound database.

   Summary:
       name                          string (must be unique within table)
       ports                         set of strings

   Details:
       name: string (must be unique within table)

       ports: set of strings
Logical_Flow TABLE
       Each row in this table represents one logical  flow.  ovn-northd  popu‐
       lates  this  table  with  logical  flows  that  implement the L2 and L3
       topologies specified in the OVN_Northbound database.  Each  hypervisor,
       via  ovn-controller,  translates  the logical flows into OpenFlow flows
       specific to its hypervisor and installs them into Open vSwitch.

       Logical flows are expressed in an OVN-specific format, described  here.
       A  logical datapath flow is much like an OpenFlow flow, except that the
       flows are written in terms of logical ports and logical  datapaths  in‐
       stead  of  physical  ports  and physical datapaths. Translation between
       logical and physical flows helps to ensure  isolation  between  logical
       datapaths.  (The  logical flow abstraction also allows the OVN central‐
       ized components to do less work, since they do not have  to  separately
       compute and push out physical flows to each chassis.)

       The default action when no flow matches is to drop packets.

       Architectural Logical Life Cycle of a Packet

       This  following  description  focuses  on  the  life  cycle of a packet
       through a logical datapath, ignoring physical details of the  implemen‐
       tation.  Please  refer to Architectural Physical Life Cycle of a Packet
       in ovn-architecture(7) for the physical information.

       The description here is written as if OVN itself executes these  steps,
       but  in  fact  OVN (that is, ovn-controller) programs Open vSwitch, via
       OpenFlow and OVSDB, to execute them on its behalf.

       At a high level, OVN passes each packet through the logical  datapath’s
       logical  ingress  pipeline,  which may output the packet to one or more
       logical port or logical multicast groups. For each such logical  output
       port,  OVN  passes  the  packet  through  the datapath’s logical egress
       pipeline, which may either drop the packet or deliver it to the  desti‐
       nation.  Between the two pipelines, outputs to logical multicast groups
       are expanded into logical ports,  so  that  the  egress  pipeline  only
       processes  a  single  logical  output  port  at a time. Between the two
       pipelines is also where, when necessary, OVN encapsulates a packet in a
       tunnel (or tunnels) to transmit to remote hypervisors.

       In more detail, to start, OVN searches the Logical_Flow table for a row
       with correct logical_datapath or  a  logical_dp_group,  a  pipeline  of
       ingress,  a  table_id of 0, and a match that is true for the packet. If
       none is found, OVN drops the packet. If OVN finds  more  than  one,  it
       chooses  the match with the highest priority. Then OVN executes each of
       the actions specified in the row’s actions column, in the order  speci‐
       fied.  Some actions, such as those to modify packet headers, require no
       further details. The next and output actions are special.

       The next action causes the above process to  be  repeated  recursively,
       except that OVN searches for table_id of 1 instead of 0. Similarly, any
       next  action  in a row found in that table would cause a further search
       for a table_id of 2, and so on. When  recursive  processing  completes,
       flow control returns to the action following next.

       The  output action also introduces recursion. Its effect depends on the
       current value of the outport field. Suppose outport designates a  logi‐
       cal  port. First, OVN compares inport to outport; if they are equal, it
       treats the output as a no-op by default. In the common case, where they
       are different, the packet enters the egress pipeline.  This  transition
       to  the  egress pipeline discards register data, e.g. reg0 ... reg9 and
       connection tracking state, to achieve uniform  behavior  regardless  of
       whether  the egress pipeline is on a different hypervisor (because reg‐
       isters aren’t preserve across tunnel encapsulation).

       To execute the egress pipeline, OVN again searches the Logical_Flow ta‐
       ble for a row with correct logical_datapath or  a  logical_dp_group,  a
       table_id of 0, a match that is true for the packet, but now looking for
       a pipeline of egress. If no matching row is found, the output becomes a
       no-op. Otherwise, OVN executes the actions for the matching flow (which
       is chosen from multiple, if necessary, as already described).

       In  the egress pipeline, the next action acts as already described, ex‐
       cept that it, of course, searches for egress flows. The output  action,
       however,  now  directly outputs the packet to the output port (which is
       now fixed, because outport is read-only within the egress pipeline).

       The description earlier assumed that  outport  referred  to  a  logical
       port.  If it instead designates a logical multicast group, then the de‐
       scription above still applies, with the addition of  fan-out  from  the
       logical  multicast  group  to  each logical port in the group. For each
       member of the group, OVN executes the logical  pipeline  as  described,
       with the logical output port replaced by the group member.

       Pipeline Stages

       ovn-northd  populates the Logical_Flow table with the logical flows de‐
       scribed in detail in ovn-northd(8).

   Summary:
       logical_datapath              optional Datapath_Binding
       logical_dp_group              optional Logical_DP_Group
       pipeline                      string, either egress or ingress
       table_id                      integer, in range 0 to 32
       priority                      integer, in range 0 to 65,535
       match                         string
       actions                       string
       tags                          map of string-string pairs
       controller_meter              optional string
       flow_desc                     optional string
       external_ids : stage-name     optional string
       external_ids : stage-hint     optional string, containing an uuid
       external_ids : source         optional string
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       logical_datapath: optional Datapath_Binding
              The logical datapath to which the logical flow belongs.

       logical_dp_group: optional Logical_DP_Group
              The group of logical datapaths to which  the  logical  flow  be‐
              longs.  This  means  that  the  same logical flow belongs to all
              datapaths in a group.

       pipeline: string, either egress or ingress
              The primary flows used for deciding on  a  packet’s  destination
              are the ingress flows. The egress flows implement ACLs. See Log‐‐
              ical Life Cycle of a Packet, above, for details.

       table_id: integer, in range 0 to 32
              The  stage in the logical pipeline, analogous to an OpenFlow ta‐
              ble number.

       priority: integer, in range 0 to 65,535
              The flow’s priority. Flows with numerically higher priority take
              precedence over those with lower. If two logical datapath  flows
              with the same priority both match, then the one actually applied
              to the packet is undefined.

       match: string
              A  matching  expression.  OVN  provides  a  superset of OpenFlow
              matching capabilities, using a syntax similar to Boolean expres‐
              sions in a programming language.

              The most important components of match  expression  are  compar
              isons   between   symbols   and   constants,   e.g.  ip4.dst  ==
              192.168.0.1, ip.proto == 6, arp.op == 1, eth.type == 0x800.  The
              logical  AND  operator &&&& and logical OR operator || can combine
              comparisons into a larger expression.

              Matching expressions also support parentheses for grouping,  the
              logical  NOT  prefix operator !, and literals 0 and 1 to express
              ``false’’ or ``true,’’ respectively. The latter is useful by it‐
              self as a catch-all expression that matches every packet.

              Match expressions also support a kind of  function  syntax.  The
              following functions are supported:

              is_chassis_resident(lport)
                     Evaluates  to  true  on  a  chassis on which logical port
                     lport (a quoted string) resides, and to false  elsewhere.
                     This function was introduced in OVN 2.7.

              Symbols

              Type.  Symbols have integer or string type. Integer symbols have
              a width in bits.

              Kinds. There are three kinds of symbols:

              •      Fields. A field symbol  represents  a  packet  header  or
                     metadata field. For example, a field named vlan.tci might
                     represent the VLAN TCI field in a packet.

                     A  field  symbol can have integer or string type. Integer
                     fields can be nominal or ordinal (see Level  of  Measure‐‐
                     ment, below).

              •      Subfields.  A subfield represents a subset of bits from a
                     larger field. For example, a field vlan.vid might be  de‐
                     fined as an alias for vlan.tci[0..11]. Subfields are pro‐
                     vided  for  syntactic  convenience,  because it is always
                     possible to instead refer to a  subset  of  bits  from  a
                     field directly.

                     Only ordinal fields (see Level of Measurement, below) may
                     have subfields. Subfields are always ordinal.

              •      Predicates.  A  predicate  is shorthand for a Boolean ex‐
                     pression. Predicates may be used much like 1-bit  fields.
                     For example, ip4 might expand to eth.type == 0x800. Pred‐
                     icates are provided for syntactic convenience, because it
                     is  always possible to instead specify the underlying ex‐
                     pression directly.

                     A predicate whose expansion refers to any  nominal  field
                     or  predicate  (see Level of Measurement, below) is nomi‐
                     nal; other predicates have Boolean level of measurement.

              Level              of              Measurement.              See
              http://en.wikipedia.org/wiki/Level_of_measurement  for  the sta‐
              tistical concept on which this classification  is  based.  There
              are three levels:

              •      Ordinal.  In statistics, ordinal values can be ordered on
                     a scale. OVN considers a field (or subfield) to be  ordi‐
                     nal  if  its  bits  can be examined individually. This is
                     true for  the  OpenFlow  fields  that  OpenFlow  or  Open
                     vSwitch makes ``maskable.’’

                     Any  use of a ordinal field may specify a single bit or a
                     range of bits, e.g. vlan.tci[13..15] refers  to  the  PCP
                     field  within the VLAN TCI, and eth.dst[40] refers to the
                     multicast bit in the Ethernet destination address.

                     OVN supports all the usual arithmetic relations (==,  !=,
                     =, >gt;>gt;, and >gt;>gt;=) on ordinal fields and their subfields,
                     because OVN can implement  these  in  OpenFlow  and  Open
                     vSwitch as collections of bitwise tests.

              •      Nominal. In statistics, nominal values cannot be usefully
                     compared  except  for  equality. This is true of OpenFlow
                     port numbers, Ethernet types, and IP protocols are  exam‐
                     ples:  all  of  these are just identifiers assigned arbi‐
                     trarily with no deeper  meaning.  In  OpenFlow  and  Open
                     vSwitch,  bits in these fields generally aren’t individu‐
                     ally addressable.

                     OVN only supports arithmetic tests for equality on  nomi‐
                     nal  fields, because OpenFlow and Open vSwitch provide no
                     way for a flow to efficiently implement other comparisons
                     on them. (A test for inequality can be sort of built  out
                     of  two flows with different priorities, but OVN matching
                     expressions always generate flows with  a  single  prior‐
                     ity.)

                     String fields are always nominal.

              •      Boolean.  A nominal field that has only two values, 0 and
                     1, is somewhat exceptional, since it is easy  to  support
                     both  equality  and inequality tests on such a field: ei‐
                     ther one can be implemented as a test for 0 or 1.

                     Only predicates (see above) have a Boolean level of  mea‐
                     surement.

                     This isn’t a standard level of measurement.

              Prerequisites.  Any symbol can have prerequisites, which are ad‐
              ditional condition implied by the use of the symbol.  For  exam‐
              ple,  For  example,  icmp4.type  symbol  might have prerequisite
              icmp4, which would cause an expression icmp4.type == 0 to be in‐
              terpreted as icmp4.type == 0 &&&& icmp4, which would in  turn  ex‐
              pand  to  icmp4.type == 0 &&&& eth.type == 0x800 &&&& ip4.proto == 1
              (assuming icmp4 is a predicate defined as suggested under  Types
              above).

              Relational operators

              All  of  the standard relational operators ==, !=, =, >gt;>gt;, and
              >gt;>gt;= are supported. Nominal fields support only  ==  and  !=,  and
              only  in  a  positive sense when outer ! are taken into account,
              e.g. given string field inport, inport == "eth0" and !(inport !=
              "eth0") are acceptable, but not inport != "eth0".

              The implementation of == (or != when it is negated), is more ef‐
              ficient than that of the other relational operators.

              Constants

              Integer constants may be expressed in decimal, hexadecimal  pre‐
              fixed by 0x, or as dotted-quad IPv4 addresses, IPv6 addresses in
              their  standard  forms, or Ethernet addresses as colon-separated
              hex digits. A constant in any of these forms may be followed  by
              a  slash  and  a second constant (the mask) in the same form, to
              form a masked constant. IPv4 and IPv6 masks may be given as  in‐
              tegers, to express CIDR prefixes.

              String  constants have the same syntax as quoted strings in JSON
              (thus, they are Unicode strings).

              Some operators support sets of constants  written  inside  curly
              braces  { ... }. Commas between elements of a set, and after the
              last elements, are optional. With ==, ``field  ==  {  constant1,
              constant2,  ...  }’’ is syntactic sugar for ``field == constant1
              || field == constant2 || .... Similarly, ``field != { constant1,
              constant2, ... }’’ is equivalent  to  ``field  !=  constant1  &&&&
              field != constant2 &&&& ...’’.

              You may refer to a set of IPv4, IPv6, or MAC addresses stored in
              the Address_Set table by its name. An Address_Set with a name of
              set1 can be referred to as $set1.

              You  may  refer to a group of logical switch ports stored in the
              Port_Group table by its name.  An  Port_Group  with  a  name  of
              port_group1 can be referred to as @port_group1.

              Additionally, you may refer to the set of addresses belonging to
              a  group  of logical switch ports stored in the Port_Group table
              by its name followed by a suffix ’_ip4’/’_ip6’. The IPv4 address
              set of a Port_Group with a name of port_group1 can  be  referred
              to  as  $port_group1_ip4,  and  the IPv6 address set of the same
              Port_Group can be referred to as $port_group1_ip6

              Miscellaneous

              Comparisons may name the symbol  or  the  constant  first,  e.g.
              tcp.src == 80 and 80 == tcp.src are both acceptable.

              Tests  for  a range may be expressed using a syntax like 1024 =
              tcp.src = 49151, which is equivalent  to  1024  =  tcp.src  &&&&
              tcp.src = 49151.

              For  a  one-bit  field  or  predicate,  a mention of its name is
              equivalent to symobl == 1, e.g. vlan.present  is  equivalent  to
              vlan.present  == 1. The same is true for one-bit subfields, e.g.
              vlan.tci[12]. There is no technical limitation  to  implementing
              the  same  for ordinal fields of all widths, but the implementa‐
              tion is expensive enough that the syntax parser requires writing
              an explicit  comparison  against  zero  to  make  mistakes  less
              likely,  e.g.  in  tcp.src  != 0 the comparison against 0 is re‐
              quired.

              Operator precedence is as shown below, from highest  to  lowest.
              There  are  two  exceptions  where parentheses are required even
              though the table would suggest that they are not: &&&& and ||  re‐
              quire parentheses when used together, and ! requires parentheses
              when  applied  to a relational expression. Thus, in (eth.type ==
              0x800 || eth.type == 0x86dd) &&&& ip.proto == 6 or !(arp.op == 1),
              the parentheses are mandatory.

              •      ()==   !=   =   >gt;>gt;   >gt;>gt;=!

              •      &&&&   ||

              Comments may be introduced by //, which extends to the next new-
              line. Comments within a line may be bracketed by /* and */. Mul‐
              tiline comments are not supported.

              Symbols

              Most of the symbols below have integer  type.  Only  inport  and
              outport have string type. inport names a logical port. Thus, its
              value  is  a logical_port name from the Port_Binding table. out‐‐
              port may name a logical port, as inport, or a logical  multicast
              group  defined  in  the Multicast_Group table. For both symbols,
              only names within the flow’s logical datapath may be used.

              The regX symbols are 32-bit integers.  The  xxregX  symbols  are
              128-bit  integers,  which  overlay four of the 32-bit registers:
              xxreg0 overlays reg0 through reg3, with reg0 supplying the most-
              significant bits  of  xxreg0  and  reg3  the  least-significant.
              xxreg1 similarly overlays reg4 through reg7.

              •      reg0...reg9xxreg0 xxreg1inport outportflags.loopbackpkt.marketh.src eth.dst eth.typevlan.tci vlan.vid vlan.pcp vlan.presentip.proto ip.dscp ip.ecn ip.ttl ip.fragip4.src ip4.dstip6.src ip6.dst ip6.labelarp.op arp.spa arp.tpa arp.sha arp.thararp.op rarp.spa rarp.tpa rarp.sha rarp.thatcp.src tcp.dst tcp.flagsudp.src udp.dstsctp.src sctp.dsticmp4.type icmp4.codeicmp6.type icmp6.codend.target nd.sll nd.tllct_mark ct_labelct_state,   which  has  several  Boolean  subfields.  The
                     ct_next action initializes the following subfields:

                     •      ct.trk: Always set to true by ct_next to  indicate
                            that  connection  tracking  has  taken  place. All
                            other ct subfields have ct.trk as a prerequisite.

                     •      ct.new: True for a new flow

                     •      ct.est: True for an established flow

                     •      ct.rel: True for a related flow

                     •      ct.rpl: True for a reply flow

                     •      ct.inv: True for a connection entry in a bad state

                     The ct_dnat, ct_snat, and ct_lb  actions  initialize  the
                     following subfields:

                     •      ct.dnat:  True  for  a packet whose destination IP
                            address has been changed.

                     •      ct.snat: True for a packet whose source IP address
                            has been changed.

              The following predicates are supported:

              •      eth.bcast expands to eth.dst == ff:ff:ff:ff:ff:ffeth.mcast expands to eth.dst[40]eth.mcastv6 expands to eth.dst[32..47] == 0x3333vlan.present expands to vlan.tci[12]ip4 expands to eth.type == 0x800ip4.src_mcast expands to ip4.src[28..31] == 0xeip4.mcast expands to ip4.dst[28..31] == 0xeip6 expands to eth.type == 0x86ddip expands to ip4 || ip6icmp4 expands to ip4 &&&& ip.proto == 1icmp6 expands to ip6 &&&& ip.proto == 58icmp expands to icmp4 || icmp6ip.is_frag expands to ip.frag[0]ip.later_frag expands to ip.frag[1]ip.first_frag expands to ip.is_frag &&&& !ip.later_fragarp expands to eth.type == 0x806rarp expands to eth.type == 0x8035ip6.mcast expands to eth.mcastv6 &&&& ip6.dst[120..127]  ==
                     0xffnd expands to icmp6.type == {135, 136} &&&& icmp6.code == 0
                     &&&& ip.ttl == 255nd_ns  expands to icmp6.type == 135 &&&& icmp6.code == 0 &&&&
                     ip.ttl == 255nd_ns_mcast expands to ip6.mcast  &&&& icmp6.type == 135 &&&&
                     icmp6.code == 0 &&&& ip.ttl == 255nd_na expands to icmp6.type == 136 &&&& icmp6.code == 0  &&&&
                     ip.ttl == 255nd_rs  expands to icmp6.type == 133 &&&& icmp6.code == 0 &&&&
                     ip.ttl == 255nd_ra expands to icmp6.type == 134 &&&& icmp6.code == 0  &&&&
                     ip.ttl == 255tcp expands to ip.proto == 6udp expands to ip.proto == 17sctp expands to ip.proto == 132

       actions: string
              Logical  datapath  actions, to be executed when the logical flow
              represented by this row is the highest-priority match.

              Actions share lexical syntax with the match column. An empty set
              of actions (or one that contains just white space or  comments),
              or  a  set  of  actions  that consists of just drop;, causes the
              matched packets to be dropped. Otherwise, the column should con‐
              tain a sequence of actions, each terminated by a semicolon.

              The following actions are defined:

              output;
                     In the ingress pipeline, this action executes the  egress
                     pipeline  as  a  subroutine.  If  outport names a logical
                     port, the egress pipeline executes once; if it is a  mul‐
                     ticast group, the egress pipeline runs once for each log‐
                     ical port in the group.

                     In  the  egress pipeline, this action performs the actual
                     output to  the  outport  logical  port.  (In  the  egress
                     pipeline, outport never names a multicast group.)

                     By  default,  output  to  the  input  port  is implicitly
                     dropped, that is, output becomes a no-op  if  outport  ==
                     inport.  Occasionally  it  may be useful to override this
                     behavior, e.g. to send an ARP reply to an ARP request; to
                     do so, use flags.loopback = 1  to  allow  the  packet  to
                     "hair-pin" back to the input port.

              next;
              next(table);
              next(pipeline=pipeline, table=table);
                   Executes  the given logical datapath table in pipeline as a
                   subroutine. The default table is  just  after  the  current
                   one. If pipeline is specified, it may be ingress or egress;
                   the  default  pipeline  is the one currently executing. Ac‐
                   tions in the both ingress and egress pipeline can use  next
                   to  jump  across the other pipeline. Actions in the ingress
                   pipeline should use next to jump into the specific table of
                   egress pipeline only if it is certain that the packets  are
                   local and not tunnelled and wants to skip certain stages in
                   the packet processing.

              field = constant;
                   Sets  data  or  metadata field field to constant value con
                   stant, e.g. outport = "vif0"; to  set  the  logical  output
                   port.  To  set  only a subset of bits in a field, specify a
                   subfield for field or a masked constant, e.g. one  may  use
                   vlan.pcp[2] = 1; or vlan.pcp = 4/4; to set the most signif‐
                   icant bit of the VLAN PCP.

                   Assigning  to  a  field  with prerequisites implicitly adds
                   those prerequisites to match; thus,  for  example,  a  flow
                   that  sets tcp.dst applies only to TCP flows, regardless of
                   whether its match mentions any TCP field.

                   Not all fields are modifiable (e.g. eth.type  and  ip.proto
                   are  read-only),  and not all modifiable fields may be par‐
                   tially modified (e.g. ip.ttl must assigned as a whole). The
                   outport field is modifiable in the ingress pipeline but not
                   in the egress pipeline.

              ovn_field = constant;
                   Sets OVN field ovn_field to constant value constant.

                   OVN supports setting the values of certain fields which are
                   not yet supported in OpenFlow to set or modify them.

                   Below are the supported OVN fields:

                   •      icmp4.frag_mtu icmp6.frag_mtu

                          This  field  sets  the  low-order  16  bits  of  the
                          ICMP{4,6}  header field that is labelled "unused" in
                          the ICMP specification as defined in  the  RFC  1191
                          with the value specified in constant.

                          Eg. icmp4.frag_mtu = 1500;

              field1 = field2;
                   Sets  data or metadata field field1 to the value of data or
                   metadata field field2, e.g. reg0 = ip4.src; copies  ip4.src
                   into reg0. To modify only a subset of a field’s bits, spec‐
                   ify  a subfield for field1 or field2 or both, e.g. vlan.pcp
                   = reg0[0..2]; copies the  least-significant  bits  of  reg0
                   into the VLAN PCP.

                   field1 and field2 must be the same type, either both string
                   or  both  integer  fields. If they are both integer fields,
                   they must have the same width.

                   If field1 or field2 has prerequisites, they are  added  im‐
                   plicitly  to  match.  It is possible to write an assignment
                   with  contradictory  prerequisites,  such  as   ip4.src   =
                   ip6.src[0..31];, but the contradiction means that a logical
                   flow with such an assignment will never be matched.

              field1 ->gt;>gt; field2;
                   Similar  to field1 = field2; except that the two values are
                   exchanged instead of copied. Both field1  and  field2  must
                   modifiable.

              push(field);
                   Push the value of field to the stack top.

              pop(field);
                   Pop  the stack top and store the value to field, which must
                   be modifiable.

              ip.ttl--;
                   Decrements the IPv4 or IPv6 TTL. If this would make the TTL
                   zero or negative, then processing of the packet  halts;  no
                   further  actions  are  processed.  (To properly handle such
                   cases, a higher-priority flow should match on ip.ttl == {0,
                   1};.)

                   Prerequisite: ip

              ct_next;
              ct_next(dnat);
              ct_next(snat);
                   Apply  connection  tracking  to  the   flow,   initializing
                   ct_state  for matching in later tables. Automatically moves
                   on to the next table, as if followed by next.

                   As a side effect, IP  fragments  will  be  reassembled  for
                   matching. If a fragmented packet is output, then it will be
                   sent  with  any overlapping fragments squashed. The connec‐
                   tion tracking state is scoped by the logical port when  the
                   action  is used in a flow for a logical switch, so overlap‐
                   ping addresses may be used. To allow traffic related to the
                   matched flow, execute ct_commit . Connection tracking state
                   is scoped by the logical topology when the action  is  used
                   in a flow for a router.

                   It  is  possible  to  have actions follow ct_next, but they
                   will not have access to any of its side-effects and is  not
                   generally useful.

              ct_commit { };
              ct_commit { ct_mark=value[/mask]; };
              ct_commit { ct_label=value[/mask]; };
              ct_commit { ct_mark=value[/mask]; ct_label=value[/mask]; };
                   Commit the flow to the connection tracking entry associated
                   with   it   by   a   previous   call   to   ct_next.   When
                   ct_mark=value[/mask] and/or ct_label=value[/mask] are  sup‐
                   plied,  ct_mark  and/or  ct_label will be set to the values
                   indicated by value[/mask] on the connection tracking entry.
                   ct_mark is a 32-bit field. ct_label is a 128-bit field. The
                   value[/mask] should be specified in hex string if more than
                   64bits are to be used. Registers and other named fields can
                   be used for value. ct_mark  and  ct_label  may  be  sub-ad‐
                   dressed in order to have specific bits set.

                   Note  that  if  you want processing to continue in the next
                   table, you must execute the next  action  after  ct_commit.
                   You  may  also  leave out next which will commit connection
                   tracking state, and then drop the  packet.  This  could  be
                   useful  for  setting ct_mark on a connection tracking entry
                   before dropping a packet, for example.

              ct_commit_to_zone(dnat);
              ct_commit_to_zone(snat);
                   Commit the flow to the  specific  zone  in  the  connection
                   tracker.  The packet is then automatically sent to the next
                   tables as if followed by next; action. The next tables will
                   see the changes in the  packet  caused  by  the  connection
                   tracker.

                   Note  that  this  action  is meaningful only in the Logical
                   Router Datapath as the Logical Switch Datapath does not use
                   separate connection tracking zones. Using  this  action  in
                   Logical  Switch  Datapath falls back to committing the flow
                   into the logical port’s conntrack zone.

              ct_dnat;
              ct_dnat(IP);
                   ct_dnat sends the packet through the DNAT zone  in  connec‐
                   tion tracking table to unDNAT any packet that was DNATed in
                   the  opposite  direction.  The packet is then automatically
                   sent to the next tables as if followed by next; action. The
                   next tables will see the changes in the  packet  caused  by
                   the connection tracker.

                   ct_dnat(IP)  sends  the  packet  through  the  DNAT zone to
                   change the destination IP address of the packet to the  one
                   provided inside the parentheses and commits the connection.
                   The packet is then automatically sent to the next tables as
                   if  followed  by next; action. The next tables will see the
                   changes in the packet caused by the connection tracker.

              ct_snat;
              ct_snat(IP);
                   ct_snat sends the packet through the SNAT  zone  to  unSNAT
                   any  packet  that was SNATed in the opposite direction. The
                   packet is automatically sent to the next tables as if  fol‐
                   lowed  by  the  next;  action. The next tables will see the
                   changes in the packet caused by the connection tracker.

                   ct_snat(IP) sends the  packet  through  the  SNAT  zone  to
                   change  the source IP address of the packet to the one pro‐
                   vided inside the parenthesis and  commits  the  connection.
                   The packet is then automatically sent to the next tables as
                   if  followed  by next; action. The next tables will see the
                   changes in the packet caused by the connection tracker.

              ct_dnat_in_czone;
              ct_dnat_in_czone(IP);
                   ct_dnat_in_czone sends the packet through  the  common  NAT
                   zone  (used  for both DNAT and SNAT) in connection tracking
                   table to unDNAT any packet that was DNATed in the  opposite
                   direction.  The  packet  is  then automatically sent to the
                   next tables as if followed by next; action. The next tables
                   will see the changes in the packet caused by the connection
                   tracker.

                   ct_dnat_in_czone(IP) sends the packet  through  the  common
                   NAT zone to change the destination IP address of the packet
                   to  the one provided inside the parentheses and commits the
                   connection. The packet is then automatically  sent  to  the
                   next tables as if followed by next; action. The next tables
                   will see the changes in the packet caused by the connection
                   tracker.

              ct_snat_in_czone;
              ct_snat_in_czone(IP);
                   ct_snat_in_czone  sends  the  packet through the common NAT
                   zone to unSNAT any packet that was SNATed in  the  opposite
                   direction. The packet is automatically sent to the next ta‐
                   bles  as  if  followed by the next; action. The next tables
                   will see the changes in the packet caused by the connection
                   tracker.

                   ct_snat_in_czone(IP) sends the packet\ through  the  common
                   NAT  zone  to change the source IP address of the packet to
                   the one provided inside the  parenthesis  and  commits  the
                   connection.  The  packet  is then automatically sent to the
                   next tables as if followed by next; action. The next tables
                   will see the changes in the packet caused by the connection
                   tracker.

              ct_clear;
                   Clears connection tracking state.

              ct_commit_nat;
                   Applies NAT and commits the connection to the CT. Automati‐
                   cally moves on to the next table, as if followed  by  next.
                   This  is  very  useful  for connections that are in related
                   state for already existing connections and allows  the  NAT
                   to be applied to them as well.

              clone { action; ... };
                   Makes  a  copy  of  the packet being processed and executes
                   each action on the copy. Actions following  the  clone  ac‐
                   tion,  if  any,  apply  to the original, unmodified packet.
                   This can be used as a  way  to  ``save  and  restore’’  the
                   packet  around  a  set  of  actions  that may modify it and
                   should not persist.

              arp { action; ... };
                   Temporarily replaces the IPv4 packet being processed by  an
                   ARP  packet  and  executes  each  nested  action on the ARP
                   packet. Actions following the arp action, if any, apply  to
                   the original, unmodified packet.

                   The  ARP packet that this action operates on is initialized
                   based on the IPv4 packet being processed, as follows. These
                   are default values that the nested  actions  will  probably
                   want to change:

                   •      eth.src unchanged

                   •      eth.dst unchanged

                   •      eth.type = 0x0806arp.op = 1 (ARP request)

                   •      arp.sha copied from eth.srcarp.spa copied from ip4.srcarp.tha = 00:00:00:00:00:00arp.tpa copied from ip4.dst

                   The  ARP packet has the same VLAN header, if any, as the IP
                   packet it replaces.

                   Prerequisite: ip4

              get_arp(P, A);
                   Parameters: logical port string field P, 32-bit IP  address
                   field A.

                   Looks  up A in P’s mac binding table. If an entry is found,
                   stores its Ethernet address in  eth.dst,  otherwise  stores
                   00:00:00:00:00:00 in eth.dst.

                   Example: get_arp(outport, ip4.dst);

              put_arp(P, A, E);
                   Parameters:  logical port string field P, 32-bit IP address
                   field A, 48-bit Ethernet address field E.

                   Adds or updates the entry for IP address A in logical  port
                   P’s mac binding table, setting its Ethernet address to E.

                   Example: put_arp(inport, arp.spa, arp.sha);

              R = lookup_arp(P, A, M);
                   Parameters:  logical port string field P, 32-bit IP address
                   field A, 48-bit MAC address field M.

                   Result: stored to a 1-bit subfield R.

                   Looks up A and M in P’s mac binding table. If an  entry  is
                   found, stores 1 in the 1-bit subfield R, else 0.

                   Example: reg0[0] = lookup_arp(inport, arp.spa, arp.sha);

              R = lookup_arp_ip(P, A);
                   Parameters:  logical port string field P, 32-bit IP address
                   field A.

                   Result: stored to a 1-bit subfield R.

                   Looks up A in P’s mac binding table. If an entry is  found,
                   stores 1 in the 1-bit subfield R, else 0.

                   Example: reg0[0] = lookup_arp_ip(inport, arp.spa);

              P = get_fdb(A);
                   Parameters:48-bit MAC address field A.

                   Looks  up  A in fdb table. If an entry is found, stores the
                   logical port key to the out parameter P.

                   Example: outport = get_fdb(eth.src);

              put_fdb(P, A);
                   Parameters: logical port string field P, 48-bit MAC address
                   field A.

                   Adds or updates the entry for Ethernet address A in fdb ta‐
                   ble, setting its logical port key to P.

                   Example: put_fdb(inport, arp.spa);

              R = lookup_fdb(P, A);
                   Parameters: 48-bit MAC address field M, logical port string
                   field P.

                   Result: stored to a 1-bit subfield R.

                   Looks up A in fdb table. If an entry is found and the logi‐
                   cal port key is P, P, stores 1 in  the  1-bit  subfield  R,
                   else 0. If flags.localnet is set then 1 is stored if an en‐
                   try  is  found and the logical port key is P or if an entry
                   is found and the entry port type is VIF.

                   Example: reg0[0] = lookup_fdb(inport, eth.src);

              nd_ns { action; ... };
                   Temporarily replaces the IPv6 packet being processed by  an
                   IPv6  Neighbor Solicitation packet and executes each nested
                   action on the IPv6 NS packet. Actions following  the  nd_ns
                   action, if any, apply to the original, unmodified packet.

                   The IPv6 NS packet that this action operates on is initial‐
                   ized  based on the IPv6 packet being processed, as follows.
                   These are default values that the nested actions will prob‐
                   ably want to change:

                   •      eth.src unchanged

                   •      eth.dst set to IPv6 multicast MAC address

                   •      eth.type = 0x86ddip6.src copied from ip6.srcip6.dst set to IPv6 Solicited-Node multicast address

                   •      icmp6.type = 135 (Neighbor Solicitation)

                   •      nd.target copied from ip6.dst

                   The IPv6 NS packet has the same VLAN header, if any, as the
                   IP packet it replaces.

                   Prerequisite: ip6

              nd_na { action; ... };
                   Temporarily replaces the IPv6 neighbor solicitation  packet
                   being  processed  by  an  IPv6  neighbor advertisement (NA)
                   packet and executes each nested action on  the  NA  packet.
                   Actions  following  the  nd_na action, if any, apply to the
                   original, unmodified packet.

                   The NA packet that this action operates on  is  initialized
                   based on the IPv6 packet being processed, as follows. These
                   are  default  values  that the nested actions will probably
                   want to change:

                   •      eth.dst exchanged with eth.srceth.type = 0x86ddip6.dst copied from ip6.srcip6.src copied from nd.targeticmp6.type = 136 (Neighbor Advertisement)

                   •      nd.target unchanged

                   •      nd.sll = 00:00:00:00:00:00nd.tll copied from eth.dst

                   The ND packet has the same VLAN header, if any, as the IPv6
                   packet it replaces.

                   Prerequisite: nd_ns

              nd_na_router { action; ... };
                   Temporarily replaces the IPv6 neighbor solicitation  packet
                   being  processed  by  an  IPv6  neighbor advertisement (NA)
                   packet, sets ND_NSO_ROUTER in the RSO  flags  and  executes
                   each  nested action on the NA packet. Actions following the
                   nd_na_router action, if any, apply to the original, unmodi‐
                   fied packet.

                   The NA packet that this action operates on  is  initialized
                   based on the IPv6 packet being processed, as follows. These
                   are  default  values  that the nested actions will probably
                   want to change:

                   •      eth.dst exchanged with eth.srceth.type = 0x86ddip6.dst copied from ip6.srcip6.src copied from nd.targeticmp6.type = 136 (Neighbor Advertisement)

                   •      nd.target unchanged

                   •      nd.sll = 00:00:00:00:00:00nd.tll copied from eth.dst

                   The ND packet has the same VLAN header, if any, as the IPv6
                   packet it replaces.

                   Prerequisite: nd_ns

              get_nd(P, A);
                   Parameters: logical port string field P, 128-bit  IPv6  ad‐
                   dress field A.

                   Looks  up A in P’s mac binding table. If an entry is found,
                   stores its Ethernet address in  eth.dst,  otherwise  stores
                   00:00:00:00:00:00 in eth.dst.

                   Example: get_nd(outport, ip6.dst);

              put_nd(P, A, E);
                   Parameters:  logical  port string field P, 128-bit IPv6 ad‐
                   dress field A, 48-bit Ethernet address field E.

                   Adds or updates the entry for IPv6  address  A  in  logical
                   port P’s mac binding table, setting its Ethernet address to
                   E.

                   Example: put_nd(inport, nd.target, nd.tll);

              R = lookup_nd(P, A, M);
                   Parameters: logical port string field P, 128-bit IP address
                   field A, 48-bit MAC address field M.

                   Result: stored to a 1-bit subfield R.

                   Looks  up  A and M in P’s mac binding table. If an entry is
                   found, stores 1 in the 1-bit subfield R, else 0.

                   Example: reg0[0] = lookup_nd(inport, ip6.src, eth.src);

              R = lookup_nd_ip(P, A);
                   Parameters: logical port string field P, 128-bit IP address
                   field A.

                   Result: stored to a 1-bit subfield R.

                   Looks up A in P’s mac binding table. If an entry is  found,
                   stores 1 in the 1-bit subfield R, else 0.

                   Example: reg0[0] = lookup_nd_ip(inport, ip6.src);

              R = put_dhcp_opts(D1 = V1, D2 = V2, ..., Dn = Vn);
                   Parameters: one or more DHCP option/value pairs, which must
                   include an offerip option (with code 0).

                   Result: stored to a 1-bit subfield R.

                   Valid only in the ingress pipeline.

                   When  this  action  is  applied  to  a  DHCP request packet
                   (DHCPDISCOVER or DHCPREQUEST), it changes the packet into a
                   DHCP reply (DHCPOFFER or DHCPACK,  respectively),  replaces
                   the  options by those specified as parameters, and stores 1
                   in R.

                   When this action is applied to a non-DHCP packet or a  DHCP
                   packet  that  is not DHCPDISCOVER or DHCPREQUEST, it leaves
                   the packet unchanged and stores 0 in R.

                   The contents of the DHCP_Option table control the DHCP  op‐
                   tion names and values that this action supports.

                   Example: reg0[0] = put_dhcp_opts(offerip = 10.0.0.2, router
                   = 10.0.0.1, netmask = 255.255.255.0, dns_server = {8.8.8.8,
                   7.7.7.7});

              R = put_dhcpv6_opts(D1 = V1, D2 = V2, ..., Dn = Vn);
                   Parameters: one or more DHCPv6 option/value pairs.

                   Result: stored to a 1-bit subfield R.

                   Valid only in the ingress pipeline.

                   When  this action is applied to a DHCPv6 request packet, it
                   changes the packet into a DHCPv6 reply,  replaces  the  op‐
                   tions by those specified as parameters, and stores 1 in R.

                   When  this  action  is applied to a non-DHCPv6 packet or an
                   invalid DHCPv6 request packet , it leaves  the  packet  un‐
                   changed and stores 0 in R.

                   The contents of the DHCPv6_Options table control the DHCPv6
                   option names and values that this action supports.

                   Example:   reg0[3]  =  put_dhcpv6_opts(ia_addr  =  aef0::4,
                   server_id               =                00:00:00:00:10:02,
                   dns_server={ae70::1,ae70::2});

              set_queue(queue_number);
                   Parameters:  Queue  number  queue_number, in the range 0 to
                   61440.

                   This is a logical equivalent of the OpenFlow set_queue  ac‐
                   tion. It affects packets that egress a hypervisor through a
                   physical interface. For nonzero queue_number, it configures
                   packet  queuing  to  match  the settings configured for the
                   Port_Binding    with    options:qdisc_queue_id     matching
                   queue_number.  When queue_number is zero, it resets queuing
                   to the default strategy.

                   Example: set_queue(10);

              ct_lb;
              ct_lb(backends=ip[:port][,...][;
              hash_fields=field1,field2,...][; ct_flag]);
                   With arguments, ct_lb commits the packet to the  connection
                   tracking  table  and  DNATs the packet’s destination IP ad‐
                   dress (and port) to the IP address or  addresses  (and  op‐
                   tional ports) specified in the backends. If multiple comma-
                   separated  IP  addresses are specified, each is given equal
                   weight for picking the DNAT address. By default, dp_hash is
                   used  as  the  OpenFlow  group  selection  method,  but  if
                   hash_fields  is  specified,  hash  is used as the selection
                   method, and the fields listed are used as the hash  fields.
                   The   ct_flag  field  represents  one  of  supported  flag:
                   skip_snat or force_snat, this flag will be stored in ct_la‐‐
                   bel register.

                   Without arguments, ct_lb sends the packet to the connection
                   tracking table to NAT the packets. If the packet is part of
                   an established connection that was previously committed  to
                   the  connection  tracker  via ct_lb(...), it will automati‐
                   cally get DNATed to the same IP address as the first packet
                   in that connection.

                   Processing automatically moves on to the next table, as  if
                   next; were specified, and later tables act on the packet as
                   modified  by  the  connection  tracker. Connection tracking
                   state is scoped by the logical port when the action is used
                   in a flow for a logical switch,  so  overlapping  addresses
                   may  be  used.  Connection  tracking state is scoped by the
                   logical topology when the action is used in a  flow  for  a
                   router.

              ct_lb_mark;
              ct_lb_mark(backends=ip[:port][,...][;
              hash_fields=field1,field2,...][; ct_flag]);
                   Same  as  ct_lb,  except that it internally uses ct_mark to
                   store the NAT flag, while ct_lb uses ct_label for the  same
                   purpose.

              R = dns_lookup();
                   Parameters: No parameters.

                   Result: stored to a 1-bit subfield R.

                   Valid only in the ingress pipeline.

                   When  this  action is applied to a valid DNS request (a UDP
                   packet typically directed to port 53), it attempts  to  re‐
                   solve  the query using the contents of the DNS table. If it
                   is successful, it changes the packet into a DNS  reply  and
                   stores  1  in  R.  If  the  action  is applied to a non-DNS
                   packet, an invalid DNS request packet, or a valid  DNS  re‐
                   quest for which the DNS table does not supply an answer, it
                   leaves the packet unchanged and stores 0 in R.

                   Regardless  of success, the action does not make any of the
                   changes to the flow that are necessary to direct the packet
                   back to the requester. The logical pipeline  can  implement
                   this behavior with matches and actions in later tables.

                   Example: reg0[3] = dns_lookup();

                   Prerequisite: udp

              R = put_nd_ra_opts(D1 = V1, D2 = V2, ..., Dn = Vn);
                   Parameters:  The following IPv6 ND Router Advertisement op‐
                   tion/value pairs as defined in RFC 4861.

                   •      addr_mode

                          Mandatory parameter which specifies the address mode
                          flag to be set in the RA  flag  options  field.  The
                          value  of  this option is a string and the following
                          values can be defined -  "slaac",  "dhcpv6_stateful"
                          and "dhcpv6_stateless".

                   •      slla

                          Mandatory  parameter  which specifies the link-layer
                          address of the interface from which the  Router  Ad‐
                          vertisement is sent.

                   •      mtu

                          Optional parameter which specifies the MTU.

                   •      prefix

                          Optional  parameter which should be specified if the
                          addr_mode  is  "slaac"  or  "dhcpv6_stateless".  The
                          value  should  be  an IPv6 prefix which will be used
                          for stateless IPv6 address configuration.  This  op‐
                          tion can be defined multiple times.

                   Result: stored to a 1-bit subfield R.

                   Valid only in the ingress pipeline.

                   When  this action is applied to an IPv6 Router solicitation
                   request packet, it changes the packet into an  IPv6  Router
                   Advertisement  reply  and adds the options specified in the
                   parameters, and stores 1 in R.

                   When this action is applied to a non-IPv6 Router  solicita‐
                   tion  packet  or an invalid IPv6 request packet , it leaves
                   the packet unchanged and stores 0 in R.

                   Example: reg0[3] = put_nd_ra_opts(addr_mode = "slaac", slla
                   = 00:00:00:00:10:02, prefix = aef0::/64, mtu = 1450);

              set_meter(rate);
              set_meter(rate, burst);
                   Parameters: rate limit int field rate in kbps,  burst  rate
                   limits int field burst in kbps.

                   This action sets the rate limit for a flow.

                   Example: set_meter(100, 1000);

              R = check_pkt_larger(L)
                   Parameters: packet length L to check for in bytes.

                   Result: stored to a 1-bit subfield R.

                   This    is   a   logical   equivalent   of   the   OpenFlow
                   check_pkt_larger action. If the packet is larger  than  the
                   length specified in L, it stores 1 in the subfield R.

                   Example: reg0[6] = check_pkt_larger(1000);

              log(key=value, ...);
                     Causes  ovn-controller  to  log the packet on the chassis
                     that processes it. Packet logging currently uses the same
                     logging mechanism as other Open vSwitch and OVN messages,
                     which means that whether and where  log  messages  appear
                     depends  on  the  local logging configuration that can be
                     configured with ovs-appctl, etc.

                     The log action takes zero or more of the  following  key-
                     value pair arguments that control what is logged:

                     name=string
                            An  optional  name for the ACL. The string is cur‐
                            rently limited to 64 bytes.

                     severity=level
                            Indicates the severity of the event. The level  is
                            one  of  following  (from  more  to less serious):
                            alert, warning,  notice,  info,  or  debug.  If  a
                            severity is not provided, the default is info.

                     verdict=value
                            The  verdict  for  packets  matching the flow. The
                            value must be one of allow, deny, or reject.

                     meter=string
                            An optional rate-limiting meter to be  applied  to
                            the logs. The string should reference a name entry
                            from  the  Meter table. The only meter action that
                            is appropriate is drop.

              fwd_group(liveness=bool, childports=port, ...);
                     Parameters: optional liveness, either true or false,  de‐
                     faulting  to false; childports, a comma-delimited list of
                     strings denoting logical ports to load balance across.

                     Load balance traffic to one or more child ports in a log‐
                     ical switch. ovn-controller translates the fwd_group into
                     an OpenFlow group with one bucket for each child port. If
                     liveness=true is specified, it also integrates the bucket
                     selection with BFD status on the tunnel interface  corre‐
                     sponding to child port.

                     Example: fwd_group(liveness=true, childports="p1", "p2");

              icmp4 { action; ... };
              icmp4_error { action; ... };
                   Temporarily  replaces the IPv4 packet being processed by an
                   ICMPv4 packet and executes each nested action on the ICMPv4
                   packet. Actions following these actions, if any,  apply  to
                   the original, unmodified packet.

                   The  ICMPv4  packet  that these actions operates on is ini‐
                   tialized based on the IPv4 packet being processed, as  fol‐
                   lows. These are default values that the nested actions will
                   probably  want  to  change.  Ethernet  and  IPv4 fields not
                   listed here are not changed:

                   •      ip.proto = 1 (ICMPv4)

                   •      ip.frag = 0 (not a fragment)

                   •      ip.ttl = 255icmp4.type = 3 (destination unreachable)

                   •      icmp4.code = 1 (host unreachable)

                   icmp4_error action is expected to be used  to  generate  an
                   ICMPv4  packet  in  response  to  an  error  in original IP
                   packet. When this action generates the  ICMPv4  packet,  it
                   also  copies  the original IP datagram following the ICMPv4
                   header as per RFC 1122: 3.2.2.

                   Prerequisite: ip4

              icmp6 { action; ... };
              icmp6_error { action; ... };
                   Temporarily replaces the IPv6 packet being processed by  an
                   ICMPv6 packet and executes each nested action on the ICMPv6
                   packet.  Actions  following the icmp6 action, if any, apply
                   to the original, unmodified packet.

                   The ICMPv6 packet that this action operates on is  initial‐
                   ized  based on the IPv6 packet being processed, as follows.
                   These are default values that the nested actions will prob‐
                   ably want to change. Ethernet and IPv6  fields  not  listed
                   here are not changed:

                   •      ip.proto = 58 (ICMPv6)

                   •      ip.ttl = 255icmp6.type = 1 (destination unreachable)

                   •      icmp6.code = 1 (administratively prohibited)

                   icmp6_error  action  is  expected to be used to generate an
                   ICMPv6 packet in response to  an  error  in  original  IPv6
                   packet.

                   Prerequisite: ip6

              tcp_reset;
                   This  action transforms the current TCP packet according to
                   the following pseudocode:

                   if (tcp.ack) {
                           tcp.seq = tcp.ack;
                   } else {
                           tcp.ack = tcp.seq + length(tcp.payload);
                           tcp.seq = 0;
                   }
                   tcp.flags = RST;

                   Then, the action drops all TCP options  and  payload  data,
                   and updates the TCP checksum. IP ttl is set to 255.

                   Prerequisite: tcp

              reject { action; ... };
                   If  the  original packet is IPv4 or IPv6 TCP packet, it re‐
                   places it with IPv4 or IPv6 TCP RST packet and executes the
                   inner actions. Otherwise it replaces it with an  ICMPv4  or
                   ICMPv6 packet and executes the inner actions.

                   The  inner  actions  should  not attempt to swap eth source
                   with eth destination and IP source with IP  destination  as
                   this action implicitly does that.

              trigger_event;
                   This action is used to allow ovs-vswitchd to report CMS re‐
                   lated  events writing them in Controller_Event table. It is
                   possible to associate a meter to a each event in  order  to
                   not overload pinctrl thread under heavy load; each meter is
                   identified  though  a  defined naming convention. Supported
                   events:

                   •      empty_lb_backends. This event is  raised  if  a  re‐
                          ceived  packet  is  destined for a load balancer VIP
                          that has no  configured  backend  destinations.  For
                          this  event,  the  event info includes the load bal‐
                          ancer VIP, the load balancer UUID, and the transport
                          protocol. Associated meter: event-elb

              igmp;
                   This action sends the packet to ovn-controller  for  multi‐
                   cast snooping.

                   Prerequisite: igmp

              bind_vport(V, P);
                   Parameters:  logical  port  string field V of type virtual,
                   logical port string field P.

                   Binds the virtual logical port V and sets the chassis  col‐
                   umn  and  virtual_parent  of  the  table Port_Binding. vir‐‐
                   tual_parent is set to P.

              handle_svc_check(P);
                   Parameters: logical port string field P.

                   Handles the service monitor reply received from the VIF  of
                   the  logical  port P. ovn-controller periodically sends out
                   the service monitor packets for the services configured  in
                   the  Service_Monitor table and this action updates the sta‐
                   tus of those services.

                   Example: handle_svc_check(inport);

              handle_dhcpv6_reply;
                   Handle DHCPv6 prefix delegation advertisements/replies from
                   a IPv6 delegation server. ovn-controller will add an  entry
                   ipv6_ra_pd_list  in  the  options table for each prefix re‐
                   ceived from the delegation server

              R = select(N1[=W1], N2[=W2], ...);
              R = select(values=(N1[=W1], N2[=W2], ...);
              hash_fields="field1,field2,...");
                   Parameters: Integer N1, N2..., with optional weight W1, W2,
                   ...

                   Result: stored to a logical field or subfield R.

                   Select from a list of integers N1, N2..., each  within  the
                   range 0 ~ 65535, and store the selected one in the field R.
                   There  must  be 2 or more integers listed, each with an op‐
                   tional weight, which is an integer within  the  range  1  ~
                   65535.  If weight is not specified, it defaults to 100. The
                   selection method is based on the  5-tuple  hash  of  packet
                   header.

                   By default, dp_hash is used as the OpenFlow group selection
                   method,  but  if values and hash_fields are specified, hash
                   is used as the selection method, and the fields listed  are
                   used as the hash fields.

                   Processing  automatically moves on to the next table, as if
                   next; were specified. The select action must be put as  the
                   last action of the logical flow when there are multiple ac‐
                   tions (actions put after select will not take effect).

                   Example:  reg8[16..31] = select(1=20, 2=30, 3=50); Example:
                   reg8[16..31]   =    select(values=(1=20,    2=30,    3=50);
                   hash_fields="ip_proto,src_ip,dst_ip");

              handle_dhcpv6_reply;
                   This action is used to parse DHCPv6 replies from IPv6 Dele‐
                   gation  Router and managed IPv6 Prefix delegation state ma‐
                   chine

              R = chk_lb_hairpin();
                   This action checks if the packet  under  consideration  was
                   destined to a load balancer VIP and it is hairpinned, i.e.,
                   after  load balancing the destination IP matches the source
                   IP. If it is so, then the 1-bit destination register  R  is
                   set to 1.

              R = chk_lb_hairpin_reply();
                   This  action  checks  if  the packet under consideration is
                   from one of the backend IP of a load balancer VIP  and  the
                   destination  IP is the load balancer VIP. If it is so, then
                   the 1-bit destination register R is set to 1.

              R = ct_snat_to_vip;
                   This action sends the  packet  through  the  SNAT  zone  to
                   change the source IP address of the packet to the load bal‐
                   ancer  VIP if the original destination IP was load balancer
                   VIP and commits the connection. This  action  applies  suc‐
                   cessfully only for the hairpinned traffic i.e if the action
                   chk_lb_hairpin  returned  success. This action doesn’t take
                   any arguments and it determines the SNAT IP internally. The
                   packet is not automatically sent to  the  next  table.  The
                   caller  has  to  execute  the next; action explicitly after
                   this action to advance the packet to the next stage.

              R = check_in_port_sec();
                   This action checks if the packet under consideration passes
                   the inport port security checks. If the  packet  fails  the
                   port  security  checks, then 1 is stored in the destination
                   register R. Else 0 is stored. The port security  values  to
                   check are retrieved from the the inport logical port.

                   This  action  should  be used in the ingress logical switch
                   pipeline.

                   Example: reg8[0..7] = check_in_port_sec();

              R = check_out_port_sec();
                   This action checks if the packet under consideration passes
                   the outport port security checks. If the packet  fails  the
                   port  security  checks, then 1 is stored in the destination
                   register R. Else 0 is stored. The port security  values  to
                   check are retrieved from the the outport logical port.

                   This  action  should  be  used in the egress logical switch
                   pipeline.

                   Example: reg8[0..7] = check_out_port_sec();

              commit_ecmp_nh(ipv6);
                   Parameters: IPv4/IPv6 traffic.

                   This action translates to an openflow "learn"  action  that
                   inserts two new flows in tables 76 and 77.

                   •      Match  on  the the 5-tuple and the expected next-hop
                          mac address in  table  76:  nw_src=ip0,  nw_dst=ip1,
                          ip_proto,tp_src=l4_port0,
                          tp_dst=l4_port1,dl_src=ethaddr and set reg9[5].

                   •      Match  on  the  5-tuple  in  table  77:  nw_src=ip1,
                          nw_dst=ip0,        ip_proto,        tp_src=l4_port1,
                          tp_dst=l4_port0 and set reg9[5] to 1

                   This action is applied if the packet arrives via ECMP route
                   or if it is routed via an ECMP route

              R = check_ecmp_nh_mac();
                   This  action  checks  if  the  packet  under  consideration
                   matches any flow in table 76. If it is so, then  the  1-bit
                   destination register R is set to 1.

              R = check_ecmp_nh();
                   This  action  checks  if  the  packet  under  consideration
                   matches the any flow in table 77. If it  is  so,  then  the
                   1-bit destination register R is set to 1.

                   commit_lb_aff(vip,  backend,  proto,  timeout); Parameters:
                   load-balancer virtual ip:port  vip,  load-balancer  backend
                   ip:port  backend,  load-balancer  protocol  proto, affinity
                   timeout timeout.

                   This action translates to an openflow "learn"  action  that
                   inserts a new flow in table 78.

                   •      Match  on the 4-tuple in table 78: nw_src=ip client,
                          nw_dst=vip ip, ip_proto,  tp_dst=vip  port  and  set
                          reg9[6]  to  1, reg4 and reg8 to backend ip and port
                          respectively. For IPv6 register xxreg1  is  used  to
                          store the backend ip.

                   This  action  is  applied for new connections received by a
                   specific load-balacer with affinity timeout configured.

              R = chk_lb_aff();
                   This  action  checks  if  the  packet  under  consideration
                   matches  any  flow in table 78. If it is so, then the 1-bit
                   destination register R is set to 1.

              R = ct_nw_dst();
                   This action checks if the packet is tracked and stores  the
                   conntrack original destination IPv4 address in the register
                   R of 32-bit size.

              R = ct_ip6_dst();
                   This  action checks if the packet is tracked and stores the
                   conntrack original destination IPv6 address in the register
                   R of 128-bit size.

              R = ct_tp_dst();
                   This action checks if the packet is tracked and stores  the
                   conntrack original L4 destination port in the register R of
                   16-bit size.

              sample(probability=packets, ...)
                   This  action causes the matched traffic to be sampled using
                   IPFIX protocol. More information about how  per-flow  IPFIX
                   sampling  works  in  OVS can be found in ovs-actions(7) and
                   ovs-vswitchd.conf.db(5).

                   In order to reliably identify each sampled packet  when  it
                   is  received  by  the IPFIX collector, this action sets the
                   content of the ObservationDomainID  and  ObservationPointID
                   IPFIX fields (see argument description below).

                   The following key-value arguments are supported:

                   probability=packets
                          The  number of sampled packets out of 65535. It must
                          be greater or equal to 1.

                   collector_set=id
                          The unsigned 32-bit integer identifier of the sample
                          collector to send sampled packets to. It must  match
                          the  value  configured  in  the  Flow_Sample_Collec‐‐
                          tor_Set Table in OVS. Defaults to 0.

                   obs_domain=id
                          An unsigned 8-bit integer that identifies  the  sam‐
                          pling  application.  It will be placed in the 8 most
                          significant bits of the ObservationDomainID field of
                          IPFIX samples. The 24 less significant bits will  be
                          automatically  filled  in with the datapath key. De‐
                          faults to 0.

                   obs_point=id
                          An unsigned 32-bit integer to be used  as  Obsserva‐‐
                          tionPointID  or  the string @cookie to indicate that
                          the first 32 bits of the Logical_Flow’s  UUID  shall
                          be used instead.

              mac_cache_use;
                   This  action resubmits to corresponding table which updates
                   the use statistics of MAC cache.

              R = dhcp_relay_req_chk(relay-ip,
                   server-ip); Parameters: Logical Router  Port  IP  relay-ip,
                   DHCP Server IP server-ip.

                   Result: stored to a 1-bit subfield R.

                   This  action  executes on the source node on which the DHCP
                   request (DHCPDISCOVER or DHCPREQUEST) originated.

                   When this action applied successfully on the  DHCP  request
                   packet,  it updates GIADDR in the DHCP packet with relay-ip
                   and stores 1 in R.

                   When this action failed to apply on the packet,  it  leaves
                   the packet unchanged and stores 0 in R.

              R = dhcp_relay_resp_chk(relay-ip,
                   server-ip);  Parameters:  Logical  Router Port IP relay-ip,
                   DHCP Server IP server-ip.

                   Result: stored to a 1-bit subfield R.

                   This action executes on the first  node  (Redirect  Chassis
                   node) which processes the DHCP response(DHCPOFFER, DHCPACK)
                   from the DHCP server.

                   When  this action applied successfully on the DHCP response
                   packet, it updates the destination MAC and  destination  IP
                   in the packet and stores 1 in R. relay-ip and server-ip are
                   used  to validate GIADDR and SERVER-ID in the DHCP response
                   packet.

                   When this action failed to apply on the packet,  it  leaves
                   the packet unchanged and stores 0 in R.

       tags: map of string-string pairs
              Key-value pairs that provide additional information to help ovn-
              controller  processing the logical flow. Below are the tags used
              by ovn-controller.

              in_out_port
                     In the logical flow’s "match" column, if a logical port P
                     is compared with "inport" and the logical flow  is  on  a
                     logical switch ingress pipeline, or if P is compared with
                     "outport"  and  the  logical  flow is on a logical switch
                     egress pipeline, and  the  expression  is  combined  with
                     other  expressions  (if  any) using the operator &&, then
                     the port P should be added as the value in this  tag.  If
                     there  are  multiple logical ports meeting this criteria,
                     one of them can be added. ovn-controller uses this infor‐
                     mation to skip parsing flows that are not needed  on  the
                     chassis.  Failing  to add the tag will affect efficiency,
                     while adding wrong value will affect correctness.

       controller_meter: optional string
              The name of the meter in table Meter to be used for all  packets
              that the logical flow might send to ovn-controller.

       flow_desc: optional string
              Human-readable  explanation  of  the  flow, this is optional and
              used to provide context for the given flow.

       external_ids : stage-name: optional string
              Human-readable name for this flow’s stage in the pipeline.

       external_ids : stage-hint: optional string, containing an uuid
              UUID of a OVN_Northbound record that caused this logical flow to
              be created. Currently used only for attribute of  logical  flows
              to northbound ACL records.

       external_ids : source: optional string
              Source  file and line number of the code that added this flow to
              the pipeline.

     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
Logical_DP_Group TABLE
       Each  row  in this table represents a group of logical datapaths refer‐
       enced by the logical_dp_group column in the Logical_Flow table.

   Summary:
       datapaths                     set of weak reference  to  Datapath_Bind‐‐
                                     ings

   Details:
       datapaths: set of weak reference to Datapath_Bindings
              List of Datapath_Binding entries.

Multicast_Group TABLE
       The rows in this table define multicast groups of logical ports. Multi‐
       cast groups allow a single packet transmitted over a tunnel to a hyper‐
       visor  to  be  delivered to multiple VMs on that hypervisor, which uses
       bandwidth more efficiently.

       Each row in this table defines a logical multicast group numbered  tun‐‐
       nel_key  within  datapath,  whose logical ports are listed in the ports
       column.

   Summary:
       datapath                      Datapath_Binding
       tunnel_key                    integer, in range 32,768 to 65,535
       name                          string
       ports                         set of weak reference to Port_Bindings

   Details:
       datapath: Datapath_Binding
              The logical datapath in which the multicast group resides.

       tunnel_key: integer, in range 32,768 to 65,535
              The value used to designate this logical egress port  in  tunnel
              encapsulations.  An index forces the key to be unique within the
              datapath. The unusual range ensures that multicast group IDs  do
              not overlap with logical port IDs.

       name: string
              The  logical multicast group’s name. An index forces the name to
              be unique within the datapath.  Logical  flows  in  the  ingress
              pipeline  may output to the group just as for individual logical
              ports, by assigning the group’s name to outport and executing an
              output action.

              Multicast group names and logical  port  names  share  a  single
              namespace  and  thus should not overlap (but the database schema
              cannot enforce this). To try to avoid conflicts, ovn-northd uses
              names that begin with _MC_.

       ports: set of weak reference to Port_Bindings
              The logical ports included in the multicast group. All of  these
              ports must be in the datapath logical datapath (but the database
              schema cannot enforce this).

Mirror TABLE
       Each  row  in  this table represents a mirror that can be used for port
       mirroring. These mirrors are referenced by the mirror_rules  column  in
       the Port_Binding table.

   Summary:
       name                          string (must be unique within table)
       filter                        string,   one  of  both,  from-lport,  or
                                     to-lport
       sink                          string
       type                          string, one of erspan, gre, or local
       index                         integer
       external_ids                  map of string-string pairs

   Details:
       name: string (must be unique within table)
              Represents the name of the mirror.

       filter: string, one of both, from-lport, or to-lport
              The value of this field represents  selection  criteria  of  the
              mirror.  to-lport  mirrors the packets coming into logical port.
              from-lport mirrors the packets going out of logical  port.  both
              mirrors for both directions.

       sink: string
              The  value  of this field represents the destination/sink of the
              mirror. If the type is gre or erspan, the  value  indicates  the
              tunnel  remote  IP  (either  IPv4 or IPv6). For a type of local,
              this field defines a local  interface  on  the  OVS  integration
              bridge  to be used as the mirror destination. The interface must
              possess external-ids:mirror-id that matches this string.

       type: string, one of erspan, gre, or local
              The value of this field specifies the mirror type - gre,  erspan
              or local.

       index: integer
              The value of this field represents the tunnel ID. If the config‐
              ured tunnel type is gre, this field represents the GRE key value
              and  if  the  configured tunnel type is erspan it represents the
              erspan_idx value. It is ignored if the type is local.

       external_ids: map of string-string pairs
              See External IDs at the beginning of this document.

Meter TABLE
       Each row in this table represents a meter that can be used for  QoS  or
       rate-limiting.

   Summary:
       name                          string (must be unique within table)
       unit                          string, either kbps or pktps
       bands                         set of 1 or more Meter_Bands

   Details:
       name: string (must be unique within table)
              A name for this meter.

              Names  that  begin  with "__" (two underscores) are reserved for
              OVN internal use and should not be added manually.

       unit: string, either kbps or pktps
              The unit for rate and burst_rate parameters in the bands  entry.
              kbps  specifies kilobits per second, and pktps specifies packets
              per second.

       bands: set of 1 or more Meter_Bands
              The bands associated with this meter. Each band specifies a rate
              above which the band is to take the action action.  If  multiple
              bands’  rates  are exceeded, then the band with the highest rate
              among the exceeded bands is selected.

Meter_Band TABLE
       Each row in this table represents a meter band which specifies the rate
       above which the configured action should be applied.  These  bands  are
       referenced by the bands column in the Meter table.

   Summary:
       action                        string, must be drop
       rate                          integer, in range 1 to 4,294,967,295
       burst_size                    integer, in range 0 to 4,294,967,295

   Details:
       action: string, must be drop
              The action to execute when this band matches. The only supported
              action is drop.

       rate: integer, in range 1 to 4,294,967,295
              The rate limit for this band, in kilobits per second or bits per
              second,  depending on whether the parent Meter entry’s unit col‐
              umn specified kbps or pktps.

       burst_size: integer, in range 0 to 4,294,967,295
              The maximum burst allowed for the band in kilobits  or  packets,
              depending  on  whether  kbps or pktps was selected in the parent
              Meter entry’s unit column. If the size is zero,  the  switch  is
              free to select some reasonable value depending on its configura‐
              tion.
Datapath_Binding TABLE
       Each  row in this table represents a logical datapath, which implements
       a logical pipeline among the ports in the Port_Binding table associated
       with it. In practice, the pipeline in a given logical  datapath  imple‐
       ments either a logical switch or a logical router.

       The  main  purpose of a row in this table is provide a physical binding
       for a logical datapath. A logical datapath does not have a physical lo‐
       cation, so its physical  binding  information  is  limited:  just  tun‐‐
       nel_key. The rest of the data in this table does not affect packet for‐
       warding.

   Summary:
       tunnel_key                    integer,  in  range 1 to 16,777,215 (must
                                     be unique within table)
       load_balancers                set of uuids
       OVN_Northbound Relationship:
         external_ids : logical-switch
                                     optional string, containing an uuid
         external_ids : logical-router
                                     optional string, containing an uuid
         external_ids : interconn-ts
                                     optional string
         Naming:
            external_ids : name      optional string
            external_ids : name2     optional string
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       tunnel_key: integer, in range 1 to 16,777,215 (must be unique within
       table)
              The tunnel key value to which the logical datapath is bound. The
              Tunnel Encapsulation section  in  ovn-architecture(7)  describes
              how  tunnel  keys  are constructed for each supported encapsula‐
              tion.

       load_balancers: set of uuids
              Not used  anymore;  kept  for  backwards  compatibility  of  the
              schema.

     OVN_Northbound Relationship:

       Each  row in Datapath_Binding is associated with some logical datapath.
       ovn-northd uses these keys to track the association of a logical  data‐
       path with concepts in the OVN_Northbound database.

       external_ids : logical-switch: optional string, containing an uuid
              For  a  logical  datapath  that  represents  a  logical  switch,
              ovn-northd stores in this key the UUID of the corresponding Log‐‐
              ical_Switch row in the OVN_Northbound database.

       external_ids : logical-router: optional string, containing an uuid
              For  a  logical  datapath  that  represents  a  logical  router,
              ovn-northd stores in this key the UUID of the corresponding Log‐‐
              ical_Router row in the OVN_Northbound database.

       external_ids : interconn-ts: optional string
              For  a  logical  datapath  that represents a logical switch that
              represents a  transit  switch  for  interconnection,  ovn-northd
              stores in this key the value of the same interconn-ts key of the
              external_ids  column  of the corresponding Logical_Switch row in
              the OVN_Northbound database.

     Naming:

       ovn-northd copies these from the  name  fields  in  the  OVN_Northbound
       database,  either from name and external_ids:neutron:router_name in the
       Logical_Router table or from name and external_ids:neutron:network_name
       in the Logical_Switch table.

       external_ids : name: optional string
              A name for the logical datapath.

       external_ids : name2: optional string
              Another name for the logical datapath.

     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
Port_Binding TABLE
       Each  row in this table binds a logical port to a realization. For most
       logical ports, this means binding to some physical location, for  exam‐
       ple  by binding a logical port to a VIF that belongs to a VM running on
       a particular hypervisor. Other logical ports,  such  as  logical  patch
       ports,  can be realized without a specific physical location, but their
       bindings are still expressed through rows in this table.

       For  every  Logical_Switch_Port  record  in  OVN_Northbound   database,
       ovn-northd  creates  a  record  in this table. ovn-northd populates and
       maintains every column except the chassis and  virtual_parent  columns,
       which it leaves empty in new records.

       ovn-controller/ovn-controller-vtep populates the chassis column for the
       records  that identify the logical ports that are located on its hyper‐
       visor/gateway, which ovn-controller/ovn-controller-vtep in  turn  finds
       out  by  monitoring the local hypervisor’s Open_vSwitch database, which
       identifies logical ports via  the  conventions  described  in  Integra‐‐
       tionGuide.rst.  (The  exceptions are for Port_Binding records with type
       of l3gateway, whose locations are identified by ovn-northd via the  op‐‐
       tions:l3gateway-chassis  column  in this table. ovn-controller is still
       responsible to populate the chassis column.)

       ovn-controller also populates  the  virtual_parent  column  of  records
       whose type is virtual.

       When  a  chassis  shuts down gracefully, it should clean up the chassis
       column that it previously had populated. (This is not critical  because
       resources  hosted  on the chassis are equally unreachable regardless of
       whether their rows are present.) To handle the case where a VM is  shut
       down abruptly on one chassis, then brought up again on a different one,
       ovn-controller/ovn-controller-vtep  must  overwrite  the chassis column
       with new information.

   Summary:
       Core Features:
         datapath                    Datapath_Binding
         logical_port                string (must be unique within table)
         encap                       optional weak reference to Encap
         additional_encap            set of weak reference to Encaps
         chassis                     optional weak reference to Chassis
         additional_chassis          set of weak reference to Chassis
         gateway_chassis             set of Gateway_Chassises
         ha_chassis_group            optional HA_Chassis_Group
         up                          optional boolean
         tunnel_key                  integer, in range 1 to 32,767
         mac                         set of strings
         port_security               set of strings
         type                        string
         requested_chassis           optional weak reference to Chassis
         requested_additional_chassis
                                     set of weak reference to Chassis
       mirror_rules                  set of weak reference to Mirrors
       Patch Options:
         options : peer              optional string
         nat_addresses               set of strings
       L3 Gateway Options:
         options : peer              optional string
         options : l3gateway-chassis
                                     optional string
         nat_addresses               set of strings
       Localnet Options:
         options : network_name      optional string
         tag                         optional integer, in range 1 to 4,095
       L2 Gateway Options:
         options : network_name      optional string
         options : l2gateway-chassis
                                     optional string
         tag                         optional integer, in range 1 to 4,095
       VTEP Options:
         options : vtep-physical-switch
                                     optional string
         options : vtep-logical-switch
                                     optional string
       VMI (or VIF) Options:
         options : requested-chassis
                                     optional string
         options : activation-strategy
                                     optional string
         options : additional-chassis-activated
                                     optional string
         options : iface-id-ver      optional string
         options : qos_min_rate      optional string
         options : qos_max_rate      optional string
         options : qos_burst         optional string
         options : qos_physical_network
                                     optional string
         options : qdisc_queue_id    optional string, containing  an  integer,
                                     in range 1 to 61,440
       Distributed Gateway Port Options:
         options : chassis-redirect-port
                                     optional string
       Chassis Redirect Options:
         options : distributed-port  optional string
         options : redirect-type     optional string
         options : always-redirect   optional string
       Nested Containers:
         parent_port                 optional string
         tag                         optional integer, in range 1 to 4,095
       Virtual ports:
         virtual_parent              optional string
       Naming:
         external_ids : name         optional string
       Common Columns:
         external_ids                map of string-string pairs

   Details:
     Core Features:

       datapath: Datapath_Binding
              The logical datapath to which the logical port belongs.

       logical_port: string (must be unique within table)
              A  logical  port.  For a logical switch port, this is taken from
              name in the OVN_Northbound database’s Logical_Switch_Port table.
              For a logical router port,  this  is  taken  from  name  in  the
              OVN_Northbound database’s Logical_Router_port table. (This means
              that  logical  switch ports and router port names must not share
              names in an OVN deployment.) OVN does not prescribe a particular
              format for the logical port ID.

       encap: optional weak reference to Encap
              Points to preferred encapsulation configuration to transmit log‐
              ical dataplane packets to this chassis. The entry  is  reference
              to a Encap record.

       additional_encap: set of weak reference to Encaps
              Points to preferred encapsulation configuration to transmit log‐
              ical  dataplane packets to this additional chassis. The entry is
              reference to a Encap record. See also additional_chassis.

       chassis: optional weak reference to Chassis
              The meaning of this column depends on the value of the type col‐
              umn. This is the meaning for each type

              (empty string)
                     The physical location of the logical  port.  To  success‐
                     fully  identify  a chassis, this column must be a Chassis
                     record. This is populated by ovn-controller.

              vtep   The physical location of the  hardware_vtep  gateway.  To
                     successfully  identify  a  chassis, this column must be a
                     Chassis record. This is populated by ovn-controller-vtep.

              localnet
                     Always empty. A localnet port is realized on every  chas‐
                     sis  that  has connectivity to the corresponding physical
                     network.

              localport
                     Always empty. A localport port is present on every  chas‐
                     sis.

              l3gateway
                     The  physical location of the L3 gateway. To successfully
                     identify a chassis, this column must be a Chassis record.
                     This is populated by ovn-controller based on the value of
                     the options:l3gateway-chassis column in this table.

              l2gateway
                     The physical location of this L2 gateway. To successfully
                     identify a chassis, this column must be a Chassis record.
                     This is populated by ovn-controller based on the value of
                     the options:l2gateway-chassis column in this table.

       additional_chassis: set of weak reference to Chassis
              The meaning of this column is the same as for the  chassis.  The
              column  is  used to track an additional physical location of the
              logical port. Used with regular (empty type) port bindings.

       gateway_chassis: set of Gateway_Chassises
              A list of Gateway_Chassis.

              This should only be populated for ports with type set  to  chas‐‐
              sisredirect.  This  column  defines  the list of chassis used as
              gateways where traffic will be redirected through.

       ha_chassis_group: optional HA_Chassis_Group
              This should only be populated for ports with type set  to  chas‐‐
              sisredirect.  This  column  defines  the HA chassis group with a
              list of HA chassis used as gateways where traffic will be  redi‐
              rected through.

       up: optional boolean
              This  is  set  to  true  whenever all OVS flows required by this
              Port_Binding have been installed. This is populated by  ovn-con‐‐
              troller.

       tunnel_key: integer, in range 1 to 32,767
              A  number  that represents the logical port in the key (e.g. STT
              key or Geneve TLV) field carried within tunnel protocol packets.

              The tunnel ID must be unique within the scope of a logical data‐
              path.

       mac: set of strings
              This column is a misnomer as it may contain MAC addresses and IP
              addresses. It is copied from the addresses column in  the  Logi‐‐
              cal_Switch_Port table in the Northbound database. It follows the
              same format as that column.

       port_security: set of strings
              This  column controls the addresses from which the host attached
              to the logical port (``the host’’) is allowed  to  send  packets
              and to which it is allowed to receive packets. If this column is
              empty, all addresses are permitted.

              It  is  copied  from  the  port_security  column  in  the  Logi‐‐
              cal_Switch_Port table in the Northbound database. It follows the
              same format as that column.

       type: string
              A type for this logical port. Logical ports can be used to model
              other types of connectivity into an OVN logical switch. The fol‐
              lowing types are defined:

              (empty string)
                     VM (or VIF) interface.

              patch  One of a pair of logical ports that act as  if  connected
                     by a patch cable. Useful for connecting two logical data‐
                     paths,  e.g.  to  connect  a  logical router to a logical
                     switch or to another logical router.

              l3gateway
                     One of a pair of logical ports that act as  if  connected
                     by a patch cable across multiple chassis. Useful for con‐
                     necting  a logical switch with a Gateway router (which is
                     only resident on a particular chassis).

              localnet
                     A  connection  to  a  locally  accessible  network   from
                     ovn-controller instances that have a corresponding bridge
                     mapping.  A  logical  switch  can  have multiple localnet
                     ports attached. This type is used to model direct connec‐
                     tivity to existing networks. In this case,  each  chassis
                     should  have  a  mapping for one of the physical networks
                     only. Note: nothing said above  implies  that  a  chassis
                     cannot  be  plugged to multiple physical networks as long
                     as they belong to different switches.

              localport
                     A connection to a local VIF. Traffic that  arrives  on  a
                     localport  is  never  forwarded  over a tunnel to another
                     chassis. These ports are present  on  every  chassis  and
                     have  the  same  address  in all of them. This is used to
                     model connectivity to local services that  run  on  every
                     hypervisor.

              l2gateway
                     An  L2 connection to a physical network. The chassis this
                     Port_Binding is bound to will serve as an L2  gateway  to
                     the network named by options:network_name.

              vtep   A  port to a logical switch on a VTEP gateway chassis. In
                     order to get this port correctly recognized  by  the  OVN
                     controller,   the  options:vtep-physical-switch  and  op‐‐
                     tions:vtep-logical-switch must also be defined.

              chassisredirect
                     A logical port that  represents  a  particular  instance,
                     bound  to a specific chassis, of an otherwise distributed
                     parent port (e.g. of type patch). A chassisredirect  port
                     should  never  be  used  as  an  inport.  When an ingress
                     pipeline sets the outport, it may set the value to a log‐
                     ical port of type chassisredirect. This  will  cause  the
                     packet  to be directed to a specific chassis to carry out
                     the egress pipeline.  At  the  beginning  of  the  egress
                     pipeline,  the  outport will be reset to the value of the
                     distributed port.

              virtual
                     Represents a logical port with an virtual ip.  This  vir‐‐
                     tual ip can be configured on a logical port (which is re‐
                     ferred as virtual parent).

       requested_chassis: optional weak reference to Chassis
              This  column  exists  so that the ovn-controller can effectively
              monitor all Port_Binding records destined for it, and is a  sup‐
              plement  to  the options:requested-chassis option. The option is
              still required so that the ovn-controller can check the CMS  in‐
              tent when the chassis pointed to does not currently exist, which
              for  example  occurs  when the ovn-controller is stopped without
              passing the -restart argument. This column  must  be  a  Chassis
              record.  This  is  populated  by ovn-northd when the options:re‐‐
              quested-chassis is defined and contains a  string  matching  the
              name  or hostname of an existing chassis. See also requested_ad‐‐
              ditional_chassis.

       requested_additional_chassis: set of weak reference to Chassis
              This column exists so that the  ovn-controller  can  effectively
              monitor  all Port_Binding records destined for it, and is a sup‐
              plement to the options:requested-chassis  option  when  multiple
              chassis  are  listed.  This  column  must  be  a list of Chassis
              records. This is populated by ovn-northd  when  the  options:re‐‐
              quested-chassis  is  defined as a list of chassis names or host‐
              names. See also requested_chassis.

       mirror_rules: set of weak reference to Mirrors
              Mirror rules that apply to the port binding. Please see the Mir‐‐
              ror table.

     Patch Options:

       These options apply to logical ports with type of patch.

       options : peer: optional string
              The logical_port in the Port_Binding record for the  other  side
              of  the  patch.  The  named logical_port must specify this logi‐‐
              cal_port in its own peer option. That is, the two patch  logical
              ports must have reversed logical_port and peer values.

       nat_addresses: set of strings
              MAC  address followed by a list of SNAT and DNAT external IP ad‐
              dresses, followed by is_chassis_resident("lport"),  where  lport
              is the name of a logical port on the same chassis where the cor‐
              responding  NAT  rules  are applied. This is used to send gratu‐
              itous ARPs for SNAT and DNAT external IP addresses via localnet,
              from the chassis where lport resides. Example: 80:fa:5b:06:72:b7
              158.36.44.22  158.36.44.24   is_chassis_resident("foo1").   This
              would  result  in generation of gratuitous ARPs for IP addresses
              158.36.44.22  and   158.36.44.24   with   a   MAC   address   of
              80:fa:5b:06:72:b7 from the chassis where the logical port "foo1"
              resides.

     L3 Gateway Options:

       These options apply to logical ports with type of l3gateway.

       options : peer: optional string
              The  logical_port  in the Port_Binding record for the other side
              of the ’l3gateway’ port. The  named  logical_port  must  specify
              this  logical_port  in  its  own  peer  option. That is, the two
              ’l3gateway’ logical ports must have  reversed  logical_port  and
              peer values.

       options : l3gateway-chassis: optional string
              The chassis in which the port resides.

       nat_addresses: set of strings
              MAC address of the l3gateway port followed by a list of SNAT and
              DNAT external IP addresses. This is used to send gratuitous ARPs
              for  SNAT  and DNAT external IP addresses via localnet. Example:
              80:fa:5b:06:72:b7 158.36.44.22 158.36.44.24. This  would  result
              in  generation  of gratuitous ARPs for IP addresses 158.36.44.22
              and 158.36.44.24 with a MAC address of  80:fa:5b:06:72:b7.  This
              is used in OVS version 2.8 and later versions.

     Localnet Options:

       These options apply to logical ports with type of localnet.

       options : network_name: optional string
              Required.    ovn-controller   uses   the   configuration   entry
              ovn-bridge-mappings to determine how to connect to this network.
              ovn-bridge-mappings is a list of network names mapped to a local
              OVS bridge that provides access to that network. An  example  of
              configuring ovn-bridge-mappings would be: .IP
              $ ovs-vsctl set open . external-ids:ovn-bridge-mappings=physnet1:br-eth0,physnet2:br-eth1

              When  a logical switch has a localnet port attached, every chas‐
              sis that may have a local vif attached to  that  logical  switch
              must  have  a  bridge mapping configured to reach that localnet.
              Traffic that arrives on a localnet port is never forwarded  over
              a  tunnel  to  another  chassis.  If there are multiple localnet
              ports in a logical switch, each chassis should only have a  sin‐
              gle  bridge  mapping  for one of the physical networks. Note: In
              case of multiple localnet ports,  to  provide  interconnectivity
              between  all  VIFs  located  on different chassis with different
              fabric connectivity, the fabric should implement  some  form  of
              routing between the segments.

       tag: optional integer, in range 1 to 4,095
              If  set,  indicates  that  the port represents a connection to a
              specific VLAN on a locally accessible network. The  VLAN  ID  is
              used  to  match  incoming  traffic and is also added to outgoing
              traffic.

     L2 Gateway Options:

       These options apply to logical ports with type of l2gateway.

       options : network_name: optional string
              Required.   ovn-controller   uses   the   configuration    entry
              ovn-bridge-mappings to determine how to connect to this network.
              ovn-bridge-mappings is a list of network names mapped to a local
              OVS  bridge  that provides access to that network. An example of
              configuring ovn-bridge-mappings would be: .IP
              $ ovs-vsctl set open . external-ids:ovn-bridge-mappings=physnet1:br-eth0,physnet2:br-eth1

              When a logical switch has a l2gateway port attached, the chassis
              that the l2gateway port is bound to must have a  bridge  mapping
              configured to reach the network identified by network_name.

       options : l2gateway-chassis: optional string
              Required. The chassis in which the port resides.

       tag: optional integer, in range 1 to 4,095
              If  set,  indicates  that the gateway is connected to a specific
              VLAN on the physical network. The VLAN ID is used to  match  in‐
              coming traffic and is also added to outgoing traffic.

     VTEP Options:

       These options apply to logical ports with type of vtep.

       options : vtep-physical-switch: optional string
              Required. The name of the VTEP gateway.

       options : vtep-logical-switch: optional string
              Required.  A  logical switch name connected by the VTEP gateway.
              Must be set when type is vtep.

     VMI (or VIF) Options:

       These options apply to logical ports with type having (empty string)

       options : requested-chassis: optional string
              If set, identifies a specific chassis (by name or hostname) that
              is allowed to bind this port. Using  this  option  will  prevent
              thrashing  between two chassis trying to bind the same port dur‐
              ing a live migration. It can also prevent similar thrashing  due
              to  a  mis-configuration,  if  a port is accidentally created on
              more than one chassis.

              If set to a comma separated list, the first entry identifies the
              main chassis and the rest are one  or  more  additional  chassis
              that are allowed to bind the same port.

              When  multiple  chassis  are  set  for the port, and the logical
              switch is connected to an external network  through  a  localnet
              port,  tunneling  is enforced for the port to guarantee delivery
              of packets directed to the port to all its locations.  This  has
              MTU  implications  because  the  network used for tunneling must
              have MTU larger than localnet for stable connectivity.

       options : activation-strategy: optional string
              If used with multiple chassis set in  requested-chassis,  speci‐
              fies  an  activation strategy for all additional chassis. By de‐
              fault, no activation strategy is used, meaning  additional  port
              locations are immediately available for use. When set to "rarp",
              the port is blocked for ingress and egress communication until a
              RARP  packet is sent from a new location. The "rarp" strategy is
              useful in live migration scenarios for virtual machines.

       options : additional-chassis-activated: optional string
              When activation-strategy is set, this option indicates that  the
              port was activated using the strategy specified.

       options : iface-id-ver: optional string
              If  set,  this port will be bound by ovn-controller only if this
              same key and value is configured in the external_ids  column  in
              the Open_vSwitch database’s Interface table.

       options : qos_min_rate: optional string
              If set, indicates the minimum guaranteed rate available for data
              sent from this interface, in bit/s.

       options : qos_max_rate: optional string
              If  set,  indicates the maximum rate for data sent from this in‐
              terface, in bit/s. The traffic will be shaped according to  this
              limit.

       options : qos_burst: optional string
              If set, indicates the maximum burst size for data sent from this
              interface, in bits.

       options : qos_physical_network: optional string
              If  set,  indicates  the  name  of the egress network name where
              traffic shaping will be applied.

       options : qdisc_queue_id: optional string, containing an integer, in
       range 1 to 61,440
              Indicates the queue number on the physical device. This is  same
              as the queue_id used in OpenFlow in struct ofp_action_enqueue.

     Distributed Gateway Port Options:

       These  options  apply  to the distributed parent ports of logical ports
       with type of chasssisredirect.

       options : chassis-redirect-port: optional string
              The name of the chassis redirect port derived from this port  if
              this port is a distributed parent of a chassis redirect port.

     Chassis Redirect Options:

       These options apply to logical ports with type of chassisredirect.

       options : distributed-port: optional string
              The  name of the distributed port for which this chassisredirect
              port represents a particular instance.

       options : redirect-type: optional string
              The value is copied from the column options  in  the  OVN_North‐
              bound  database’s  Logical_Router_Port table for the distributed
              parent of this port.

       options : always-redirect: optional string
              A boolean option that is set to true if the  distributed  parent
              of this chassis redirect port does not need distributed process‐
              ing.

     Nested Containers:

       These columns support containers nested within a VM. Specifically, they
       are  used  when type is empty and logical_port identifies the interface
       of a container spawned inside a VM. They are empty  for  containers  or
       VMs that run directly on a hypervisor.

       parent_port: optional string
              This  is taken from parent_name in the OVN_Northbound database’s
              Logical_Switch_Port table.

       tag: optional integer, in range 1 to 4,095
              Identifies the VLAN tag in the network traffic  associated  with
              that container’s network interface.

              This  column is used for a different purpose when type is local‐‐
              net (see Localnet Options, above) or l2gateway (see  L2  Gateway
              Options, above).

     Virtual ports:

       virtual_parent: optional string
              This  column is set by ovn-controller with one of the value from
              the options:virtual-parents  in  the  OVN_Northbound  database’s
              Logical_Switch_Port table when the OVN action bind_vport is exe‐
              cuted.  ovn-controller also sets the chassis column when it exe‐
              cutes this action with its chassis id.

              ovn-controller sets this column only if the type is "virtual".

     Naming:

       external_ids : name: optional string
              For a logical switch port, ovn-northd copies  this  from  exter‐‐
              nal_ids:neutron:port_name  in  the  Logical_Switch_Port table in
              the OVN_Northbound database, if it is a nonempty string.

              For a logical switch port, ovn-northd  does  not  currently  set
              this key.

     Common Columns:

       external_ids: map of string-string pairs
              See External IDs at the beginning of this document.

              The  ovn-northd  program  populates this column with all entries
              into the external_ids column of the Logical_Switch_Port and Log‐‐
              ical_Router_Port tables of the OVN_Northbound database.

MAC_Binding TABLE
       Each row in this table specifies a binding from an  IP  address  to  an
       Ethernet  address  that  has  been discovered through ARP (for IPv4) or
       neighbor discovery (for IPv6). This table is primarily used to discover
       bindings on physical networks, because IP-to-MAC bindings  for  virtual
       machines are usually populated statically into the Port_Binding table.

       This  table  expresses  a  functional  relationship:  MAC_Binding(logi‐‐
       cal_port, ip) = mac.

       In outline, the lifetime of a logical router’s MAC binding  looks  like
       this:

              1.  On  hypervisor  1, a logical router determines that a packet
                  should be forwarded to IP address A on  one  of  its  router
                  ports.  It  uses  its logical flow table to determine that A
                  lacks a static IP-to-MAC binding and the get_arp  action  to
                  determine that it lacks a dynamic IP-to-MAC binding.

              2.  Using  an  OVN logical arp action, the logical router gener‐
                  ates and sends a broadcast ARP request to the  router  port.
                  It drops the IP packet.

              3.  The  logical switch attached to the router port delivers the
                  ARP request to all of its ports. (It might make sense to de‐
                  liver it only to ports that have no static  IP-to-MAC  bind‐
                  ings, but this could also be surprising behavior.)

              4.  A host or VM on hypervisor 2 (which might be the same as hy‐
                  pervisor  1)  attached to the logical switch owns the IP ad‐
                  dress in question. It composes an ARP reply and unicasts  it
                  to the logical router port’s Ethernet address.

              5.  The  logical  switch  delivers  the ARP reply to the logical
                  router port.

              6.  The logical router flow table executes a put_arp action.  To
                  record  the  IP-to-MAC binding, ovn-controller adds a row to
                  the MAC_Binding table.

              7.  On  hypervisor  1,  ovn-controller  receives   the   updated
                  MAC_Binding table from the OVN southbound database. The next
                  packet  destined to A through the logical router is sent di‐
                  rectly to the bound Ethernet address.

   Summary:
       logical_port                  string
       ip                            string
       mac                           string
       timestamp                     integer
       datapath                      Datapath_Binding

   Details:
       logical_port: string
              The logical port on which the binding was discovered.

       ip: string
              The bound IP address.

       mac: string
              The Ethernet address to which the IP is bound.

       timestamp: integer
              The timestamp in msec when the MAC binding was added or updated.
              Records that existed before this column will have 0.

       datapath: Datapath_Binding
              The logical datapath to which the logical port belongs.

DHCP_Options TABLE
       Each row in this table stores the DHCP Options supported by native  OVN
       DHCP.  ovn-northd populates this table with the supported DHCP options.
       ovn-controller looks up this table to get the DHCP codes  of  the  DHCP
       options  defined in the "put_dhcp_opts" action. Please refer to the RFC
       2132 "https://tools.ietf.org/html/rfc2132" for  the  possible  list  of
       DHCP options that can be defined here.

   Summary:
       name                          string
       code                          integer, in range 0 to 254
       type                          string,  one  of  bool, domains, host_id,
                                     ipv4, static_routes, str, uint16, uint32,
                                     or uint8

   Details:
       name: string
              Name of the DHCP option.

              Example. name="router"

       code: integer, in range 0 to 254
              DHCP option code for the DHCP option as defined in the RFC 2132.

              Example. code=3

       type: string, one of bool, domains, host_id, ipv4, static_routes, str,
       uint16, uint32, or uint8
              Data type of the DHCP option code.

              value: bool
                     This indicates that the value of the  DHCP  option  is  a
                     bool.

                     Example.       "name=ip_forward_enable",       "code=19",
                     "type=bool".

                     put_dhcp_opts(..., ip_forward_enable = 1,...)

              value: uint8
                     This indicates that the value of the DHCP  option  is  an
                     unsigned int8 (8 bits)

                     Example. "name=default_ttl", "code=23", "type=uint8".

                     put_dhcp_opts(..., default_ttl = 50,...)

              value: uint16
                     This  indicates  that  the value of the DHCP option is an
                     unsigned int16 (16 bits).

                     Example. "name=mtu", "code=26", "type=uint16".

                     put_dhcp_opts(..., mtu = 1450,...)

              value: uint32
                     This indicates that the value of the DHCP  option  is  an
                     unsigned int32 (32 bits).

                     Example. "name=lease_time", "code=51", "type=uint32".

                     put_dhcp_opts(..., lease_time = 86400,...)

              value: ipv4
                     This  indicates  that  the value of the DHCP option is an
                     IPv4 address or addresses.

                     Example. "name=router", "code=3", "type=ipv4".

                     put_dhcp_opts(..., router = 10.0.0.1,...)

                     Example. "name=dns_server", "code=6", "type=ipv4".

                     put_dhcp_opts(..., dns_server = {8.8.8.8 7.7.7.7},...)

              value: static_routes
                     This indicates that the value of the DHCP option contains
                     a pair of IPv4 route and next hop addresses.

                     Example.    "name=classless_static_route",    "code=121",
                     "type=static_routes".

                     put_dhcp_opts(...,        classless_static_route        =
                     {30.0.0.0/24,10.0.0.4,0.0.0.0/0,10.0.0.1}...)

              value: str
                     This indicates that the value of the  DHCP  option  is  a
                     string.

                     Example. "name=host_name", "code=12", "type=str".

              value: host_id
                     This  indicates  that  the  value of the DHCP option is a
                     host_id. It can either be a host_name or an IP address.

                     Example. "name=tftp_server", "code=66", "type=host_id".

              value: domains
                     This indicates that the value of the DHCP option is a do‐
                     main name or a comma separated list of domain names.

                     Example. "name=domain_search_list", "code=119", "type=do‐
                     mains".
DHCPv6_Options TABLE
       Each row in this table stores the DHCPv6 Options  supported  by  native
       OVN  DHCPv6.  ovn-northd populates this table with the supported DHCPv6
       options. ovn-controller looks up this table to get the DHCPv6 codes  of
       the  DHCPv6 options defined in the put_dhcpv6_opts action. Please refer
       to RFC 3315 and RFC 3646 for the list of DHCPv6 options that can be de‐
       fined here.

   Summary:
       name                          string
       code                          integer, in range 0 to 254
       type                          string, one of domain, ipv6, mac, or str

   Details:
       name: string
              Name of the DHCPv6 option.

              Example. name="ia_addr"

       code: integer, in range 0 to 254
              DHCPv6 option code for the DHCPv6 option as defined in  the  ap‐
              propriate RFC.

              Example. code=3

       type: string, one of domain, ipv6, mac, or str
              Data type of the DHCPv6 option code.

              value: ipv6
                     This  indicates that the value of the DHCPv6 option is an
                     IPv6 address(es).

                     Example. "name=ia_addr", "code=5", "type=ipv6".

                     put_dhcpv6_opts(..., ia_addr = ae70::4,...)

              value: str
                     This indicates that the value of the DHCPv6 option  is  a
                     string.

                     Example. "name=domain_search", "code=24", "type=str".

                     put_dhcpv6_opts(..., domain_search = ovn.domain,...)

              value: mac
                     This  indicates  that the value of the DHCPv6 option is a
                     MAC address.

                     Example. "name=server_id", "code=2", "type=mac".

                     put_dhcpv6_opts(..., server_id = 01:02:03:04L05:06,...)
Connection TABLE
       Configuration for a database connection to  an  Open  vSwitch  database
       (OVSDB) client.

       This  table  primarily  configures  the  Open  vSwitch  database server
       (ovsdb-server).

       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)
         read_only                   boolean
         role                        string
       Client Failure Detection and Handling:
         max_backoff                 optional integer, at least 1,000
         inactivity_probe            optional integer
       Status:
         is_connected                boolean
         status : last_error         optional string
         status : state              optional string, one of ACTIVE,  BACKOFF,
                                     CONNECTING, IDLE, or VOID
         status : sec_since_connect  optional  string,  containing an integer,
                                     at least 0
         status : sec_since_disconnect
                                     optional string, containing  an  integer,
                                     at least 0
         status : locks_held         optional string
         status : locks_waiting      optional string
         status : locks_lost         optional string
         status : n_connections      optional  string,  containing an integer,
                                     at least 2
         status : bound_port         optional string, containing an integer
       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 methods for clients.

              The following connection methods are currently supported:

              ssl:host[:port]
                     The specified SSL port on the given host, which  can  ei‐
                     ther  be a DNS name (if built with unbound library) or an
                     IP address. A valid SSL configuration  must  be  provided
                     when  this form is used, this configuration can be speci‐
                     fied via command-line options or the SSL table.

                     If port is not specified, it defaults to 6640.

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

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

                     If port is not specified, it defaults to 6640.

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

                     If port is not specified, it defaults to 6640.

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

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

                     If port is not specified, it defaults to 6640.

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

       read_only: boolean
              true to restrict these connections  to  read-only  transactions,
              false to allow them to modify the database.

       role: string
              String containing role name for this connection entry.

     Client Failure Detection and Handling:

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

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

     Status:

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

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

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

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

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

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

              VOID   Connection is disabled.

              BACKOFF
                     Attempting to reconnect at an increasing period.

              CONNECTING
                     Attempting to connect.

              ACTIVE Connected, remote host responsive.

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

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

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

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

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

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

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

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

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

     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
SSL TABLE
       SSL configuration for ovn-sb database access.

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

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

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

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

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

       ssl_protocols: string
              List of SSL protocols to be enabled for SSL connections. The de‐
              fault when this option is omitted is TLSv1,TLSv1.1,TLSv1.2.

       ssl_ciphers: string
              List of ciphers (in OpenSSL cipher string  format)  to  be  sup‐
              ported  for  SSL  connections.  The  default when this option is
              omitted is HIGH:!aNULL:!MD5.

     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
DNS TABLE
       Each  row  in  this  table  stores  the  DNS  records.  The  OVN action
       dns_lookup uses this table for DNS resolution.

   Summary:
       records                       map of string-string pairs
       datapaths                     set of 1 or more Datapath_Bindings
       options : ovn-owned           optional string
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       records: map of string-string pairs
              Key-value pair of DNS records with DNS query name as the key and
              a string of IP address(es) separated by comma or  space  as  the
              value.  ovn-northd stores the DNS query name in all lowercase in
              order to facilitate case-insensitive lookups.

              Example:  "vm1.ovn.org" = "10.0.0.4 aef0::4"

       datapaths: set of 1 or more Datapath_Bindings
              The DNS records defined in the column records  will  be  applied
              only  to  the DNS queries originating from the datapaths defined
              in this column.

       options : ovn-owned: optional string
              This column indicates that all the Domains  in  this  table  are
              owned  by OVN, and all DNS queries for those domains will be an‐
              swered locally by either an IP address or DNS rejection.

     Common Columns:

       external_ids: map of string-string pairs
              See External IDs at the beginning of this document.

RBAC_Role TABLE
       Role table for role-based access controls.

   Summary:
       name                          string
       permissions                   map of string-weak reference to RBAC_Per‐‐
                                     mission pairs

   Details:
       name: string
              The role name, corresponding to the role column in  the  Connec‐‐
              tion table.

       permissions: map of string-weak reference to RBAC_Permission pairs
              A mapping of table names to rows in the RBAC_Permission table.

RBAC_Permission TABLE
       Permissions table for role-based access controls.

   Summary:
       table                         string
       authorization                 set of strings
       insert_delete                 boolean
       update                        set of strings

   Details:
       table: string
              Name of table to which this row applies.

       authorization: set of strings
              Set  of  strings  identifying columns and column:key pairs to be
              compared with client ID. At least one match is required in order
              to be authorized. A zero-length string is treated as  a  special
              value indicating all clients should be considered authorized.

       insert_delete: boolean
              When  "true",  row  insertions  and authorized row deletions are
              permitted.

       update: set of strings
              Set of strings identifying columns and column:key pairs that au‐
              thorized clients are allowed to modify.

Gateway_Chassis TABLE
       Association of Port_Binding rows of type chassisredirect to a  Chassis.
       The  traffic  going out through a specific chassisredirect port will be
       redirected to a chassis, or a set of them in high availability configu‐
       rations.

   Summary:
       name                          string (must be unique within table)
       chassis                       optional weak reference to Chassis
       priority                      integer, in range 0 to 32,767
       options                       map of string-string pairs
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       name: string (must be unique within table)
              Name of the Gateway_Chassis.

              A   suggested,   but   not   required   naming   convention   is
              ${port_name}_${chassis_name}.

       chassis: optional weak reference to Chassis
              The Chassis to which we send the traffic.

       priority: integer, in range 0 to 32,767
              This  is  the  priority  the  specific  Chassis  among all Gate‐
              way_Chassis belonging to the same Port_Binding.

       options: map of string-string pairs
              Reserved for future use.

     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
HA_Chassis TABLE
   Summary:
       chassis                       optional weak reference to Chassis
       priority                      integer, in range 0 to 32,767
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       chassis: optional weak reference to Chassis
              The Chassis which provides the HA functionality.

       priority: integer, in range 0 to 32,767
              Priority  of  the HA chassis. Chassis with highest priority will
              be the active chassis in the HA chassis group.

     Common Columns:

       external_ids: map of string-string pairs
              See External IDs at the beginning of this document.

HA_Chassis_Group TABLE
       Table representing a group of chassis which can provide High availabil‐
       ity services. Each chassis in the group is  represented  by  the  table
       HA_Chassis.  The  HA  chassis  with highest priority will be the active
       chassis of this group. If the active chassis failover is detected,  the
       HA  chassis with the next higher priority takes over the responsibility
       of providing the HA. If ha_chassis_group column of the table Port_Bind‐‐
       ing references this table, then this  HA  chassis  group  provides  the
       gateway  functionality  and redirects the gateway traffic to the active
       chassis of this group.

   Summary:
       name                          string (must be unique within table)
       ha_chassis                    set of HA_Chassises
       ref_chassis                   set of weak reference to Chassis
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       name: string (must be unique within table)
              Name of the HA_Chassis_Group. Name should be unique.

       ha_chassis: set of HA_Chassises
              A list of HA_Chassis which belongs to this group.

       ref_chassis: set of weak reference to Chassis
              The set of Chassis that reference this HA chassis group. To  de‐
              termine  the  correct  Chassis,  find  the  chassisredirect type
              Port_Binding  that  references   this   HA_Chassis_Group.   This
              Port_Binding  is  derived  from  some particular logical router.
              Starting from that LR, find the set of all logical switches  and
              routers  connected  to it, directly or indirectly, across router
              ports that link one LRP to another or to a LSP. For each LSP  in
              these  logical switches, find the corresponding Port_Binding and
              add its bound Chassis (if any) to ref_chassis.

     Common Columns:

       external_ids: map of string-string pairs
              See External IDs at the beginning of this document.

Controller_Event TABLE
       Database table used by ovn-controller to  report  CMS  related  events.
       Please note there is no guarantee a given event is written exactly once
       in  the  db.  It is CMS responsibility to squash duplicated lines or to
       filter out duplicated events

   Summary:
       event_type                    string, must be empty_lb_backends
       event_info                    map of string-string pairs
       chassis                       optional weak reference to Chassis
       seq_num                       integer

   Details:
       event_type: string, must be empty_lb_backends
              Event type occurred

       event_info: map of string-string pairs
              Key-value pairs used to specify event info to the CMS.  Possible
              values are:

              •      vip: VIP reported for the empty_lb_backends event

              •      protocol:    Transport    protocol   reported   for   the
                     empty_lb_backends event

              •      load_balancer: UUID of the load balancer reported for the
                     empty_lb_backends event

       chassis: optional weak reference to Chassis
              This column is a Chassis record to identify the chassis that has
              managed a given event.

       seq_num: integer
              Event sequence number. Global counter for  controller  generated
              events. It can be used by the CMS to detect possible duplication
              of the same event.

IP_Multicast TABLE
       IP Multicast configuration options. For now only applicable to IGMP.

   Summary:
       datapath                      weak  reference to Datapath_Binding (must
                                     be unique within table)
       enabled                       optional boolean
       querier                       optional boolean
       table_size                    optional integer
       idle_timeout                  optional integer
       query_interval                optional integer
       seq_no                        integer
       Querier configuration options:
         eth_src                     string
         ip4_src                     string
         ip6_src                     string
         query_max_resp              optional integer

   Details:
       datapath: weak reference to Datapath_Binding (must be unique within ta‐
       ble)
              Datapath_Binding entry for which these configuration options are
              defined.

       enabled: optional boolean
              Enables/disables multicast snooping. Default: disabled.

       querier: optional boolean
              Enables/disables multicast querying. If enabled  then  multicast
              querying is enabled by default.

       table_size: optional integer
              Limits  the  number of multicast groups that can be learned. De‐
              fault: 2048 groups per datapath.

       idle_timeout: optional integer
              Configures the idle timeout (in seconds) for IP multicast groups
              if multicast snooping is enabled. Default: 300 seconds.

       query_interval: optional integer
              Configures the  interval  (in  seconds)  for  sending  multicast
              queries if snooping and querier are enabled. Default: idle_time‐‐
              out/2 seconds.

       seq_no: integer
              ovn-controller  reads  this value and flushes all learned multi‐
              cast groups when it detects that seq_no was changed.

     Querier configuration options:

       The ovn-controller process that runs on OVN hypervisor nodes  uses  the
       following columns to determine field values in IGMP/MLD queries that it
       originates:

       eth_src: string
              Source Ethernet address.

       ip4_src: string
              Source IPv4 address.

       ip6_src: string
              Source IPv6 address.

       query_max_resp: optional integer
              Value  (in seconds) to be used as "max-response" field in multi‐
              cast queries. Default: 1 second.

IGMP_Group TABLE
       Contains learned IGMP groups indexed by address/datapath/chassis.

   Summary:
       address                       string
       protocol                      string
       datapath                      optional weak reference to Datapath_Bind‐‐
                                     ing
       chassis                       optional weak reference to Chassis
       ports                         set of weak reference to Port_Bindings
       chassis_name                  string

   Details:
       address: string
              Destination IPv4 address for the IGMP group.

       protocol: string
              Group protocol version either IGMPv1,v2,v3 or MLDv1,v2.

       datapath: optional weak reference to Datapath_Binding
              Datapath to which this IGMP group belongs.

       chassis: optional weak reference to Chassis
              Chassis to which this IGMP group belongs.

       ports: set of weak reference to Port_Bindings
              The destination port bindings for this IGMP group.

       chassis_name: string
              The chassis that inserted this record. This column is  used  for
              RBAC purposes only.

Service_Monitor TABLE
       Each  row  in  this table configures monitoring a service for its live‐
       ness. The service can be an IPv4 TCP or UDP service. ovn-controller pe‐
       riodically sends out service monitor packets and updates the status  of
       the service.

       ovn-northd  uses  this  feature  to  implement the load balancer health
       check feature offered to the CMS through the northbound database.

   Summary:
       Configuration:
         ip                          string
         protocol                    optional string, either tcp or udp
         port                        integer, in range 0 to 65,535
         logical_port                string
         src_mac                     string
         src_ip                      string
         chassis_name                string
         options : interval          optional string, containing an integer
         options : timeout           optional string, containing an integer
         options : success_count     optional string, containing an integer
         options : failure_count     optional string, containing an integer
       Status Reporting:
         status                      optional string, one of  error,  offline,
                                     or online
       Common Columns:
         external_ids                map of string-string pairs

   Details:
     Configuration:

       ovn-northd sets these columns and values to configure the service moni‐
       tor.

       ip: string
              IP of the service to be monitored. Only IPv4 is supported.

       protocol: optional string, either tcp or udp
              The protocol of the service.

       port: integer, in range 0 to 65,535
              The TCP or UDP port of the service.

       logical_port: string
              The VIF of the logical port on which the service is running. The
              ovn-controller that binds this logical_port monitors the service
              by sending periodic monitor packets.

       src_mac: string
              Source Ethernet address to use in the service monitor packet.

       src_ip: string
              Source  IPv4  or  IPv6  address  to  use  in the service monitor
              packet.

       chassis_name: string
              The name of the chassis where the logical port is bound.

       options : interval: optional string, containing an integer
              The interval, in seconds, between service monitor checks.

       options : timeout: optional string, containing an integer
              The time, in seconds, after  which  the  service  monitor  check
              times out.

       options : success_count: optional string, containing an integer
              The  number of successful checks after which the service is con‐
              sidered online.

       options : failure_count: optional string, containing an integer
              The number of failure checks after which the service is  consid‐
              ered offline.

     Status Reporting:

       The  ovn-controller  on the chassis that hosts the logical_port updates
       this column to report the service’s status.

       status: optional string, one of error, offline, or online
              For TCP service, ovn-controller sends a SYN to the  service  and
              expects an ACK response to consider the service to be online.

              For  UDP  service, ovn-controller sends a UDP packet to the ser‐
              vice and doesn’t expect any reply. If it receives an ICMP reply,
              then it considers the service to be offline.

     Common Columns:

       external_ids: map of string-string pairs
              See External IDs at the beginning of this document.

Load_Balancer TABLE
       Each row represents a load balancer.

   Summary:
       name                          string
       vips                          map of string-string pairs
       protocol                      optional string, one of sctp, tcp, or udp
       datapaths                     set of Datapath_Bindings
       datapath_group                optional Logical_DP_Group
       ls_datapath_group             optional Logical_DP_Group
       lr_datapath_group             optional Logical_DP_Group
       Load_Balancer options:
         options : hairpin_snat_ip   optional string
         options : hairpin_orig_tuple
                                     optional string, either true or false
       Common Columns:
         external_ids                map of string-string pairs

   Details:
       name: string
              A name for the load balancer. This name has no  special  meaning
              or  purpose other than to provide convenience for human interac‐
              tion with the ovn-nb database.

       vips: map of string-string pairs
              A map of virtual IP addresses (and an optional port number  with
              :  as  a separator) associated with this load balancer and their
              corresponding endpoint IP addresses (and optional  port  numbers
              with : as separators) separated by commas.

       protocol: optional string, one of sctp, tcp, or udp
              Valid  protocols  are  tcp,  udp, or sctp. This column is useful
              when a port number is provided as part of the  vips  column.  If
              this  column  is  empty and a port number is provided as part of
              vips column, OVN assumes the protocol to be tcp.

       datapaths: set of Datapath_Bindings
              Datapaths to which this load balancer applies to.

       datapath_group: optional Logical_DP_Group
              Deprecated. The group of datapaths to which this  load  balancer
              applies  to.  This  means that the same load balancer applies to
              all datapaths in a group.

       ls_datapath_group: optional Logical_DP_Group
              The group of datapaths to which this load balancer  applies  to.
              This  means that the same load balancer applies to all datapaths
              in a group.

       lr_datapath_group: optional Logical_DP_Group
              The group of logical router datapaths to which  this  load  bal‐
              ancer applies to. This means that the same load balancer applies
              to all datapaths in a group.

     Load_Balancer options:

       options : hairpin_snat_ip: optional string
              IP  to  be  used  as  source IP for packets that have been hair-
              pinned after load balancing. This value is  automatically  popu‐
              lated by ovn-northd.

       options : hairpin_orig_tuple: optional string, either true or false
              This value is automatically set to true by ovn-northd when orig‐
              inal  destination  IP  and  transport  port of the load balanced
              packets are stored in registers reg1, reg2, xxreg1.

     Common Columns:

       external_ids: map of string-string pairs
              See External IDs at the beginning of this document.

BFD TABLE
       Contains BFD parameter for ovn-controller bfd configuration.

   Summary:
       Configuration:
         src_port                    integer, in range 49,152 to 65,535
         disc                        integer
         logical_port                string
         dst_ip                      string
         min_tx                      integer
         min_rx                      integer
         detect_mult                 integer
         chassis_name                string
         options                     map of string-string pairs
         external_ids                map of string-string pairs
       Status Reporting:
         status                      string, one of admin_down, down, init, or
                                     up

   Details:
     Configuration:

       src_port: integer, in range 49,152 to 65,535
              udp source port used in bfd control  packets.  The  source  port
              MUST be in the range 49152 through 65535 (RFC5881 section 4).

       disc: integer
              A unique, nonzero discriminator value generated by the transmit‐
              ting  system,  used to demultiplex multiple BFD sessions between
              the same pair of systems.

       logical_port: string
              OVN logical port when BFD engine is running.

       dst_ip: string
              BFD peer IP address.

       min_tx: integer
              This is the minimum interval, in milliseconds,  that  the  local
              system  would like to use when transmitting BFD Control packets,
              less any jitter applied. The value zero is reserved.

       min_rx: integer
              This is the minimum interval, in milliseconds, between  received
              BFD  Control  packets that this system is capable of supporting,
              less any jitter applied by the sender. If this  value  is  zero,
              the  transmitting system does not want the remote system to send
              any periodic BFD Control packets.

       detect_mult: integer
              Detection time multiplier.  The  negotiated  transmit  interval,
              multiplied  by  this  value, provides the Detection Time for the
              receiving system in Asynchronous mode.

       chassis_name: string
              The name of the chassis where the logical port is bound.

       options: map of string-string pairs
              Reserved for future use.

       external_ids: map of string-string pairs
              See External IDs at the beginning of this document.

     Status Reporting:

       status: string, one of admin_down, down, init, or up
              BFD port logical states. Possible values are:

              •      admin_downdowninitup
FDB TABLE
       This table is primarily used to learn the MACs observed on a VIF (or  a
       localnet  port  with  ’localnet_learn_fdb’  enabled) which belongs to a
       Logical_Switch_Port record in OVN_Northbound  whose  port  security  is
       disabled  and  ’unknown’ address set. If port security is disabled on a
       Logical_Switch_Port record, OVN should allow traffic  with  any  source
       mac  from  the  VIF. This table will be used to deliver a packet to the
       VIF, If a packet’s eth.dst is learnt.

   Summary:
       mac                           string
       dp_key                        integer, in range 1 to 16,777,215
       port_key                      integer, in range 1 to 16,777,215
       timestamp                     integer

   Details:
       mac: string
              The learnt mac address.

       dp_key: integer, in range 1 to 16,777,215
              The key of the datapath on which this FDB was learnt.

       port_key: integer, in range 1 to 16,777,215
              The key of the port binding on which this FDB was learnt.

       timestamp: integer
              The timestamp in msec when the FDB was added or updated. Records
              that existed before this column will have 0.

Static_MAC_Binding TABLE
       Each record represents a Static_MAC_Binding entry for a logical router.

   Summary:
       logical_port                  string
       ip                            string
       mac                           string
       override_dynamic_mac          boolean
       datapath                      Datapath_Binding

   Details:
       logical_port: string
              The logical router port for the binding.

       ip: string
              The bound IP address.

       mac: string
              The Ethernet address to which the IP is bound.

       override_dynamic_mac: boolean
              Override dynamically learnt MACs.

       datapath: Datapath_Binding
              The logical datapath to which the logical router port belongs.

Chassis_Template_Var TABLE
       Each record represents the set of template variable instantiations  for
       a given chassis and is populated by ovn-northd from the contents of the
       OVN_Northbound.Chassis_Template_Var table.

   Summary:
       chassis                       string (must be unique within table)
       variables                     map of string-string pairs

   Details:
       chassis: string (must be unique within table)
              The chassis this set of variable values applies to.

       variables: map of string-string pairs
              The set of variable values for a given chassis.

Open vSwitch 24.09.90          DB Schema 20.37.0                     ovn-sb(5)