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...reg9
• xxreg0 xxreg1
• inport outport
• flags.loopback
• pkt.mark
• eth.src eth.dst eth.type
• vlan.tci vlan.vid vlan.pcp vlan.present
• ip.proto ip.dscp ip.ecn ip.ttl ip.frag
• ip4.src ip4.dst
• ip6.src ip6.dst ip6.label
• arp.op arp.spa arp.tpa arp.sha arp.tha
• rarp.op rarp.spa rarp.tpa rarp.sha rarp.tha
• tcp.src tcp.dst tcp.flags
• udp.src udp.dst
• sctp.src sctp.dst
• icmp4.type icmp4.code
• icmp6.type icmp6.code
• nd.target nd.sll nd.tll
• ct_mark ct_label
• ct_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:ff
• eth.mcast expands to eth.dst[40]
• eth.mcastv6 expands to eth.dst[32..47] == 0x3333
• vlan.present expands to vlan.tci[12]
• ip4 expands to eth.type == 0x800
• ip4.src_mcast expands to ip4.src[28..31] == 0xe
• ip4.mcast expands to ip4.dst[28..31] == 0xe
• ip6 expands to eth.type == 0x86dd
• ip expands to ip4 || ip6
• icmp4 expands to ip4 &&&& ip.proto == 1
• icmp6 expands to ip6 &&&& ip.proto == 58
• icmp expands to icmp4 || icmp6
• ip.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_frag
• arp expands to eth.type == 0x806
• rarp expands to eth.type == 0x8035
• ip6.mcast expands to eth.mcastv6 &&&& ip6.dst[120..127] ==
0xff
• nd expands to icmp6.type == {135, 136} &&&& icmp6.code == 0
&&&& ip.ttl == 255
• nd_ns expands to icmp6.type == 135 &&&& icmp6.code == 0 &&&&
ip.ttl == 255
• nd_ns_mcast expands to ip6.mcast &&&& icmp6.type == 135 &&&&
icmp6.code == 0 &&&& ip.ttl == 255
• nd_na expands to icmp6.type == 136 &&&& icmp6.code == 0 &&&&
ip.ttl == 255
• nd_rs expands to icmp6.type == 133 &&&& icmp6.code == 0 &&&&
ip.ttl == 255
• nd_ra expands to icmp6.type == 134 &&&& icmp6.code == 0 &&&&
ip.ttl == 255
• tcp expands to ip.proto == 6
• udp expands to ip.proto == 17
• sctp 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 = 0x0806
• arp.op = 1 (ARP request)
• arp.sha copied from eth.src
• arp.spa copied from ip4.src
• arp.tha = 00:00:00:00:00:00
• arp.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 = 0x86dd
• ip6.src copied from ip6.src
• ip6.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.src
• eth.type = 0x86dd
• ip6.dst copied from ip6.src
• ip6.src copied from nd.target
• icmp6.type = 136 (Neighbor Advertisement)
• nd.target unchanged
• nd.sll = 00:00:00:00:00:00
• nd.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.src
• eth.type = 0x86dd
• ip6.dst copied from ip6.src
• ip6.src copied from nd.target
• icmp6.type = 136 (Neighbor Advertisement)
• nd.target unchanged
• nd.sll = 00:00:00:00:00:00
• nd.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 = 255
• icmp4.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 = 255
• icmp6.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], ...);
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.
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);
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.
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_down
• down
• init
• up
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)