1 <?xml version="1.0" encoding="utf-8"?>
2 <database title="Hardware VTEP Database">
4 This schema specifies relations that a VTEP can use to integrate
5 physical ports into logical switches maintained by a network
6 virtualization controller such as NSX.
14 VXLAN Tunnel End Point, an entity which originates and/or terminates
20 Hardware Switch Controller.
25 Network Virtualization Controller, e.g. NSX.
30 Virtual Routing and Forwarding instance.
34 <table name="Global" title="Top-level configuration.">
35 Top-level configuration for a hardware VTEP. There must be
36 exactly one record in the <ref table="Global"/> table.
38 <column name="switches">
39 The physical switches managed by the VTEP.
42 <group title="Database Configuration">
44 These columns primarily configure the database server
45 (<code>ovsdb-server</code>), not the hardware VTEP itself.
48 <column name="managers">
49 Database clients to which the database server should connect or
50 to which it should listen, along with options for how these
51 connection should be configured. See the <ref table="Manager"/>
52 table for more information.
57 <table name="Manager" title="OVSDB management connection.">
59 Configuration for a database connection to an Open vSwitch Database
64 The database server can initiate and maintain active connections
65 to remote clients. It can also listen for database connections.
68 <group title="Core Features">
69 <column name="target">
70 <p>Connection method for managers.</p>
72 The following connection methods are currently supported:
75 <dt><code>ssl:<var>ip</var></code>[<code>:<var>port</var></code>]</dt>
78 The specified SSL <var>port</var> (default: 6632) on the host at
79 the given <var>ip</var>, which must be expressed as an IP address
83 SSL key and certificate configuration happens outside the
88 <dt><code>tcp:<var>ip</var></code>[<code>:<var>port</var></code>]</dt>
90 The specified TCP <var>port</var> (default: 6632) on the host at
91 the given <var>ip</var>, which must be expressed as an IP address
94 <dt><code>pssl:</code>[<var>port</var>][<code>:<var>ip</var></code>]</dt>
97 Listens for SSL connections on the specified TCP <var>port</var>
98 (default: 6632). If <var>ip</var>, which must be expressed as an
99 IP address (not a DNS name), is specified, then connections are
100 restricted to the specified local IP address.
103 <dt><code>ptcp:</code>[<var>port</var>][<code>:<var>ip</var></code>]</dt>
105 Listens for connections on the specified TCP <var>port</var>
106 (default: 6632). If <var>ip</var>, which must be expressed as an
107 IP address (not a DNS name), is specified, then connections are
108 restricted to the specified local IP address.
114 <group title="Client Failure Detection and Handling">
115 <column name="max_backoff">
116 Maximum number of milliseconds to wait between connection attempts.
117 Default is implementation-specific.
120 <column name="inactivity_probe">
121 Maximum number of milliseconds of idle time on connection to the
122 client before sending an inactivity probe message. If the Open
123 vSwitch database does not communicate with the client for the
124 specified number of seconds, it will send a probe. If a
125 response is not received for the same additional amount of time,
126 the database server assumes the connection has been broken
127 and attempts to reconnect. Default is implementation-specific.
128 A value of 0 disables inactivity probes.
132 <group title="Status">
133 <column name="is_connected">
134 <code>true</code> if currently connected to this manager,
135 <code>false</code> otherwise.
138 <column name="status" key="last_error">
139 A human-readable description of the last error on the connection
140 to the manager; i.e. <code>strerror(errno)</code>. This key
141 will exist only if an error has occurred.
144 <column name="status" key="state"
145 type='{"type": "string", "enum": ["set", ["VOID", "BACKOFF", "CONNECTING", "ACTIVE", "IDLE"]]}'>
147 The state of the connection to the manager:
150 <dt><code>VOID</code></dt>
151 <dd>Connection is disabled.</dd>
153 <dt><code>BACKOFF</code></dt>
154 <dd>Attempting to reconnect at an increasing period.</dd>
156 <dt><code>CONNECTING</code></dt>
157 <dd>Attempting to connect.</dd>
159 <dt><code>ACTIVE</code></dt>
160 <dd>Connected, remote host responsive.</dd>
162 <dt><code>IDLE</code></dt>
163 <dd>Connection is idle. Waiting for response to keep-alive.</dd>
166 These values may change in the future. They are provided only for
171 <column name="status" key="sec_since_connect"
172 type='{"type": "integer", "minInteger": 0}'>
173 The amount of time since this manager last successfully connected
174 to the database (in seconds). Value is empty if manager has never
175 successfully connected.
178 <column name="status" key="sec_since_disconnect"
179 type='{"type": "integer", "minInteger": 0}'>
180 The amount of time since this manager last disconnected from the
181 database (in seconds). Value is empty if manager has never
185 <column name="status" key="locks_held">
186 Space-separated list of the names of OVSDB locks that the connection
187 holds. Omitted if the connection does not hold any locks.
190 <column name="status" key="locks_waiting">
191 Space-separated list of the names of OVSDB locks that the connection is
192 currently waiting to acquire. Omitted if the connection is not waiting
196 <column name="status" key="locks_lost">
197 Space-separated list of the names of OVSDB locks that the connection
198 has had stolen by another OVSDB client. Omitted if no locks have been
199 stolen from this connection.
202 <column name="status" key="n_connections"
203 type='{"type": "integer", "minInteger": 2}'>
205 When <ref column="target"/> specifies a connection method that
206 listens for inbound connections (e.g. <code>ptcp:</code> or
207 <code>pssl:</code>) and more than one connection is actually active,
208 the value is the number of active connections. Otherwise, this
209 key-value pair is omitted.
212 When multiple connections are active, status columns and key-value
213 pairs (other than this one) report the status of one arbitrarily
219 <group title="Connection Parameters">
221 Additional configuration for a connection between the manager
222 and the database server.
225 <column name="other_config" key="dscp"
226 type='{"type": "integer"}'>
227 The Differentiated Service Code Point (DSCP) is specified using 6 bits
228 in the Type of Service (TOS) field in the IP header. DSCP provides a
229 mechanism to classify the network traffic and provide Quality of
230 Service (QoS) on IP networks.
232 The DSCP value specified here is used when establishing the
233 connection between the manager and the database server. If no
234 value is specified, a default value of 48 is chosen. Valid DSCP
235 values must be in the range 0 to 63.
240 <table name="Physical_Switch" title="A physical switch.">
241 A physical switch that implements a VTEP.
243 <column name="ports">
244 The physical ports within the switch.
247 <column name="tunnels">
248 Tunnels created by this switch as instructed by the NVC.
251 <group title="Network Status">
252 <column name="management_ips">
253 IPv4 or IPv6 addresses at which the switch may be contacted
254 for management purposes.
257 <column name="tunnel_ips">
259 IPv4 or IPv6 addresses on which the switch may originate or
264 This column is intended to allow a <ref table="Manager"/> to
265 determine the <ref table="Physical_Switch"/> that terminates
266 the tunnel represented by a <ref table="Physical_Locator"/>.
271 <group title="Identification">
273 Symbolic name for the switch, such as its hostname.
276 <column name="description">
277 An extended description for the switch, such as its switch login
281 <group title="Error Notification">
283 An entry in this column indicates to the NVC that this switch
284 has encountered a fault. The switch must clear this column
285 when the fault has been cleared.
288 <column name="switch_fault_status" key="mac_table_exhaustion">
289 Indicates that the switch has been unable to process MAC
290 entries requested by the NVC due to lack of table resources.
293 <column name="switch_fault_status" key="tunnel_exhaustion">
294 Indicates that the switch has been unable to create tunnels
295 requested by the NVC due to lack of resources.
298 <column name="switch_fault_status" key="unspecified_fault">
299 Indicates that an error has occurred in the switch but that no
300 more specific information is available.
306 <table name="Tunnel" title="A tunnel created by a physical switch.">
307 A tunnel created by a <ref table="Physical_Switch"/>.
309 <column name="local">
310 Tunnel end-point local to the physical switch.
313 <column name="remote">
314 Tunnel end-point remote to the physical switch.
317 <group title="Bidirectional Forwarding Detection (BFD)">
319 BFD, defined in RFC 5880, allows point to point detection of
320 connectivity failures by occasional transmission of BFD control
321 messages. VTEPs are expected to implement BFD.
325 BFD operates by regularly transmitting BFD control messages at a
326 rate negotiated independently in each direction. Each endpoint
327 specifies the rate at which it expects to receive control messages,
328 and the rate at which it's willing to transmit them. An endpoint
329 which fails to receive BFD control messages for a period of three
330 times the expected reception rate will signal a connectivity
331 fault. In the case of a unidirectional connectivity issue, the
332 system not receiving BFD control messages will signal the problem
333 to its peer in the messages it transmits.
337 A hardware VTEP is expected to use BFD to determine reachability of
338 devices at the end of the tunnels with which it exchanges data. This
339 can enable the VTEP to choose a functioning service node among a set of
340 service nodes providing high availability. It also enables the NVC to
341 report the health status of tunnels.
345 In most cases the BFD peer of a hardware VTEP will be an Open vSwitch
346 instance. The Open vSwitch implementation of BFD aims to comply
347 faithfully with the requirements put forth in RFC 5880. Open vSwitch
348 does not implement the optional Authentication or ``Echo Mode''
352 <group title="BFD Local Configuration">
354 The HSC writes the key-value pairs in the
355 <ref column="bfd_config_local"/> column to specifiy the local
356 configurations to be used for BFD sessions on this tunnel.
359 <column name="bfd_config_local" key="bfd_dst_mac">
360 Set to an Ethernet address in the form
361 <var>xx</var>:<var>xx</var>:<var>xx</var>:<var>xx</var>:<var>xx</var>:<var>xx</var>
362 to set the MAC expected as destination for received BFD packets.
365 <column name="bfd_config_local" key="bfd_dst_ip">
366 Set to an IPv4 address to set the IP address that is expected as destination
367 for received BFD packets. The default is <code>169.254.1.0</code>.
372 <group title="BFD Remote Configuration">
374 The <ref column="bfd_config_remote"/> column is the remote
375 counterpart of the <ref column="bfd_config_local"/> column.
376 The NVC writes the key-value pairs in this column.
379 <column name="bfd_config_remote" key="bfd_dst_mac">
380 Set to an Ethernet address in the form
381 <var>xx</var>:<var>xx</var>:<var>xx</var>:<var>xx</var>:<var>xx</var>:<var>xx</var>
382 to set the destination MAC to be used for transmitted BFD packets.
383 The default is <code>00:23:20:00:00:01</code>.
386 <column name="bfd_config_remote" key="bfd_dst_ip">
387 Set to an IPv4 address to set the IP address used as destination
388 for transmitted BFD packets. The default is <code>169.254.1.1</code>.
393 <group title="BFD Parameters">
395 The NVC sets up key-value pairs in the <ref column="bfd_params"/>
396 column to enable and configure BFD.
399 <column name="bfd_params" key="enable" type='{"type": "boolean"}'>
400 True to enable BFD on this tunnel.
403 <column name="bfd_params" key="min_rx"
404 type='{"type": "integer", "minInteger": 1}'>
405 The shortest interval, in milliseconds, at which this BFD session
406 offers to receive BFD control messages. The remote endpoint may
407 choose to send messages at a slower rate. Defaults to
411 <column name="bfd_params" key="min_tx"
412 type='{"type": "integer", "minInteger": 1}'>
413 The shortest interval, in milliseconds, at which this BFD session is
414 willing to transmit BFD control messages. Messages will actually be
415 transmitted at a slower rate if the remote endpoint is not willing to
416 receive as quickly as specified. Defaults to <code>100</code>.
419 <column name="bfd_params" key="decay_min_rx" type='{"type": "integer"}'>
420 An alternate receive interval, in milliseconds, that must be greater
421 than or equal to <ref column="bfd" key="min_rx"/>. The
422 implementation switches from <ref column="bfd" key="min_rx"/> to <ref
423 column="bfd" key="decay_min_rx"/> when there is no obvious incoming
424 data traffic at the interface, to reduce the CPU and bandwidth cost
425 of monitoring an idle interface. This feature may be disabled by
426 setting a value of 0. This feature is reset whenever <ref
427 column="bfd" key="decay_min_rx"/> or <ref column="bfd" key="min_rx"/>
431 <column name="bfd_params" key="forwarding_if_rx" type='{"type": "boolean"}'>
432 True to consider the interface capable of packet I/O as long as it
433 continues to receive any packets (not just BFD packets). This
434 prevents link congestion that causes consecutive BFD control packets
435 to be lost from marking the interface down.
438 <column name="bfd_params" key="cpath_down" type='{"type": "boolean"}'>
439 Set to true to notify the remote endpoint that traffic should not be
440 forwarded to this system for some reason other than a connectivty
441 failure on the interface being monitored. The typical underlying
442 reason is ``concatenated path down,'' that is, that connectivity
443 beyond the local system is down. Defaults to false.
446 <column name="bfd_params" key="check_tnl_key" type='{"type": "boolean"}'>
447 Set to true to make BFD accept only control messages with a tunnel
448 key of zero. By default, BFD accepts control messages with any
454 <group title="BFD Status">
456 The VTEP sets key-value pairs in the <ref column="bfd_status"/>
457 column to report the status of BFD on this tunnel. When BFD is
458 not enabled, with <ref column="bfd_params" key="enable"/>, the
459 HSC clears all key-value pairs from <ref column="bfd_status"/>.
462 <column name="bfd_status" key="state"
463 type='{"type": "string",
464 "enum": ["set", ["admin_down", "down", "init", "up"]]}'>
465 Reports the state of the BFD session. The BFD session is fully
466 healthy and negotiated if <code>UP</code>.
469 <column name="bfd_status" key="forwarding" type='{"type": "boolean"}'>
470 Reports whether the BFD session believes this tunnel
471 may be used to forward traffic. Typically this means the local session
472 is signaling <code>UP</code>, and the remote system isn't signaling a
473 problem such as concatenated path down.
476 <column name="bfd_status" key="diagnostic">
477 In case of a problem, set to a short message that reports what the
478 local BFD session thinks is wrong.
481 <column name="bfd_status" key="remote_state"
482 type='{"type": "string",
483 "enum": ["set", ["admin_down", "down", "init", "up"]]}'>
484 Reports the state of the remote endpoint's BFD session.
487 <column name="bfd_status" key="remote_diagnostic">
488 In case of a problem, set to a short message that reports what the
489 remote endpoint's BFD session thinks is wrong.
495 <table name="Physical_Port" title="A port within a physical switch.">
496 A port within a <ref table="Physical_Switch"/>.
498 <column name="vlan_bindings">
499 Identifies how VLANs on the physical port are bound to logical switches.
500 If, for example, the map contains a (VLAN, logical switch) pair, a packet
501 that arrives on the port in the VLAN is considered to belong to the
502 paired logical switch.
505 <column name="vlan_stats">
506 Statistics for VLANs bound to logical switches on the physical port. An
507 implementation that fully supports such statistics would populate this
508 column with a mapping for every VLAN that is bound in <ref
509 column="vlan_bindings"/>. An implementation that does not support such
510 statistics or only partially supports them would not populate this column
511 or partially populate it, respectively.
514 <group title="Identification">
516 Symbolic name for the port. The name ought to be unique within a given
517 <ref table="Physical_Switch"/>, but the database is not capable of
521 <column name="description">
522 An extended description for the port.
525 <group title="Error Notification">
527 An entry in this column indicates to the NVC that the physical port has
528 encountered a fault. The switch must clear this column when the errror
531 <column name="port_fault_status" key="invalid_vlan_map">
533 Indicates that a VLAN-to-logical-switch mapping requested by
534 the controller could not be instantiated by the switch
535 because of a conflict with local configuration.
538 <column name="port_fault_status" key="unspecified_fault">
540 Indicates that an error has occurred on the port but that no
541 more specific information is available.
548 <table name="Logical_Binding_Stats" title="Statistics for a VLAN on a physical port bound to a logical network.">
549 Reports statistics for the <ref table="Logical_Switch"/> with which a VLAN
550 on a <ref table="Physical_Port"/> is associated.
552 <group title="Statistics">
553 These statistics count only packets to which the binding applies.
555 <column name="packets_from_local">
556 Number of packets sent by the <ref table="Physical_Switch"/>.
559 <column name="bytes_from_local">
560 Number of bytes in packets sent by the <ref table="Physical_Switch"/>.
563 <column name="packets_to_local">
564 Number of packets received by the <ref table="Physical_Switch"/>.
567 <column name="bytes_to_local">
568 Number of bytes in packets received by the <ref
569 table="Physical_Switch"/>.
574 <table name="Logical_Switch" title="A layer-2 domain.">
575 A logical Ethernet switch, whose implementation may span physical and
576 virtual media, possibly crossing L3 domains via tunnels; a logical layer-2
577 domain; an Ethernet broadcast domain.
581 <group title="Per Logical-Switch Tunnel Key">
583 Tunnel protocols tend to have a field that allows the tunnel
584 to be partitioned into sub-tunnels: VXLAN has a VNI, GRE and
585 STT have a key, CAPWAP has a WSI, and so on. We call these
586 generically ``tunnel keys.'' Given that one needs to use a
587 tunnel key at all, there are at least two reasonable ways to
594 Per <ref table="Logical_Switch"/>+<ref table="Physical_Locator"/>
595 pair. That is, each logical switch may be assigned a different
596 tunnel key on every <ref table="Physical_Locator"/>. This model is
601 In this model, <ref table="Physical_Locator"/> carries the tunnel
602 key. Therefore, one <ref table="Physical_Locator"/> record will
603 exist for each logical switch carried at a given IP destination.
609 Per <ref table="Logical_Switch"/>. That is, every tunnel
610 associated with a particular logical switch carries the same tunnel
611 key, regardless of the <ref table="Physical_Locator"/> to which the
612 tunnel is addressed. This model may ease switch implementation
613 because it imposes fewer requirements on the hardware datapath.
617 In this model, <ref table="Logical_Switch"/> carries the tunnel
618 key. Therefore, one <ref table="Physical_Locator"/> record will
619 exist for each IP destination.
624 <column name="tunnel_key">
626 This column is used only in the tunnel key per <ref
627 table="Logical_Switch"/> model (see above), because only in that
628 model is there a tunnel key associated with a logical switch.
632 For <code>vxlan_over_ipv4</code> encapsulation, this column
633 is the VXLAN VNI that identifies a logical switch. It must
634 be in the range 0 to 16,777,215.
639 <group title="Identification">
641 Symbolic name for the logical switch.
644 <column name="description">
645 An extended description for the logical switch, such as its switch
651 <table name="Ucast_Macs_Local" title="Unicast MACs (local)">
653 Mapping of unicast MAC addresses to tunnels (physical
654 locators). This table is written by the HSC, so it contains the
655 MAC addresses that have been learned on physical ports by a
660 A MAC address that has been learned by the VTEP.
663 <column name="logical_switch">
664 The Logical switch to which this mapping applies.
667 <column name="locator">
668 The physical locator to be used to reach this MAC address. In
669 this table, the physical locator will be one of the tunnel IP
670 addresses of the appropriate VTEP.
673 <column name="ipaddr">
674 The IP address to which this MAC corresponds. Optional field for
675 the purpose of ARP supression.
680 <table name="Ucast_Macs_Remote" title="Unicast MACs (remote)">
682 Mapping of unicast MAC addresses to tunnels (physical
683 locators). This table is written by the NVC, so it contains the
684 MAC addresses that the NVC has learned. These include VM MAC
685 addresses, in which case the physical locators will be
686 hypervisor IP addresses. The NVC will also report MACs that it
687 has learned from other HSCs in the network, in which case the
688 physical locators will be tunnel IP addresses of the
693 A MAC address that has been learned by the NVC.
696 <column name="logical_switch">
697 The Logical switch to which this mapping applies.
700 <column name="locator">
701 The physical locator to be used to reach this MAC address. In
702 this table, the physical locator will be either a hypervisor IP
703 address or a tunnel IP addresses of another VTEP.
706 <column name="ipaddr">
707 The IP address to which this MAC corresponds. Optional field for
708 the purpose of ARP supression.
713 <table name="Mcast_Macs_Local" title="Multicast MACs (local)">
715 Mapping of multicast MAC addresses to tunnels (physical
716 locators). This table is written by the HSC, so it contains the
717 MAC addresses that have been learned on physical ports by a
718 VTEP. These may be learned by IGMP snooping, for example. This
719 table also specifies how to handle unknown unicast and broadcast packets.
724 A MAC address that has been learned by the VTEP.
727 The keyword <code>unknown-dst</code> is used as a special
728 ``Ethernet address'' that indicates the locations to which
729 packets in a logical switch whose destination addresses do not
730 otherwise appear in <ref table="Ucast_Macs_Local"/> (for
731 unicast addresses) or <ref table="Mcast_Macs_Local"/> (for
732 multicast addresses) should be sent.
736 <column name="logical_switch">
737 The Logical switch to which this mapping applies.
740 <column name="locator_set">
741 The physical locator set to be used to reach this MAC address. In
742 this table, the physical locator set will be contain one or more tunnel IP
743 addresses of the appropriate VTEP(s).
748 <table name="Mcast_Macs_Remote" title="Multicast MACs (remote)">
750 Mapping of multicast MAC addresses to tunnels (physical
751 locators). This table is written by the NVC, so it contains the
752 MAC addresses that the NVC has learned. This
753 table also specifies how to handle unknown unicast and broadcast
757 Multicast packet replication may be handled by a service node,
758 in which case the physical locators will be IP addresses of
759 service nodes. If the VTEP supports replication onto multiple
760 tunnels, then this may be used to replicate directly onto
761 VTEP-hyperisor tunnels.
766 A MAC address that has been learned by the NVC.
769 The keyword <code>unknown-dst</code> is used as a special
770 ``Ethernet address'' that indicates the locations to which
771 packets in a logical switch whose destination addresses do not
772 otherwise appear in <ref table="Ucast_Macs_Remote"/> (for
773 unicast addresses) or <ref table="Mcast_Macs_Remote"/> (for
774 multicast addresses) should be sent.
778 <column name="logical_switch">
779 The Logical switch to which this mapping applies.
782 <column name="locator_set">
783 The physical locator set to be used to reach this MAC address. In
784 this table, the physical locator set will be either a service node IP
785 address or a set of tunnel IP addresses of hypervisors (and
786 potentially other VTEPs).
789 <column name="ipaddr">
790 The IP address to which this MAC corresponds. Optional field for
791 the purpose of ARP supression.
796 <table name="Logical_Router" title="A logical L3 router.">
798 A logical router, or VRF. A logical router may be connected to one or more
799 logical switches. Subnet addresses and interface addresses may be configured on the
803 <column name="switch_binding">
804 Maps from an IPv4 or IPv6 address prefix in CIDR notation to a
805 logical switch. Multiple prefixes may map to the same switch. By
806 writing a 32-bit (or 128-bit for v6) address with a /N prefix
807 length, both the router's interface address and the subnet
808 prefix can be configured. For example, 192.68.1.1/24 creates a
809 /24 subnet for the logical switch attached to the interface and
810 assigns the address 192.68.1.1 to the router interface.
813 <column name="static_routes">
814 One or more static routes, mapping IP prefixes to next hop IP addresses.
817 <group title="Identification">
819 Symbolic name for the logical router.
822 <column name="description">
823 An extended description for the logical router.
828 <table name="Arp_Sources_Local" title="ARP source addresses for logical routers">
830 MAC address to be used when a VTEP issues ARP requests on behalf
835 A distributed logical router is implemented by a set of VTEPs
836 (both hardware VTEPs and vswitches). In order for a given VTEP
837 to populate the local ARP cache for a logical router, it issues
838 ARP requests with a source MAC address that is unique to the VTEP. A
839 single per-VTEP MAC can be re-used across all logical
840 networks. This table contains the MACs that are used by the
841 VTEPs of a given HSC. The table provides the mapping from MAC to
842 physical locator for each VTEP so that replies to the ARP
843 requests can be sent back to the correct VTEP using the
844 appropriate physical locator.
847 <column name="src_mac">
848 The source MAC to be used by a given VTEP.
851 <column name="locator">
852 The <ref table="Physical_Locator"/> to use for replies to ARP
853 requests from this MAC address.
857 <table name="Arp_Sources_Remote" title="ARP source addresses for logical routers">
859 MAC address to be used when a remote VTEP issues ARP requests on behalf
864 This table is the remote counterpart of <ref
865 table="Arp_sources_local"/>. The NVC writes this table to notify
866 the HSC of the MACs that will be used by remote VTEPs when they
867 issue ARP requests on behalf of a distributed logical router.
870 <column name="src_mac">
871 The source MAC to be used by a given VTEP.
874 <column name="locator">
875 The <ref table="Physical_Locator"/> to use for replies to ARP
876 requests from this MAC address.
880 <table name="Physical_Locator_Set">
882 A set of one or more <ref table="Physical_Locator"/>s.
886 This table exists only because OVSDB does not have a way to
887 express the type ``map from string to one or more <ref
888 table="Physical_Locator"/> records.''
891 <column name="locators"/>
894 <table name="Physical_Locator">
896 Identifies an endpoint to which logical switch traffic may be
897 encapsulated and forwarded.
901 For the <code>vxlan_over_ipv4</code> encapsulation, the only
902 encapsulation defined so far, all endpoints associated with a given <ref
903 table="Logical_Switch"/> must use a common tunnel key, which is carried
904 in the <ref table="Logical_Switch" column="tunnel_key"/> column of <ref
905 table="Logical_Switch"/>.
909 For some encapsulations yet to be defined, we expect <ref
910 table="Physical_Locator"/> to identify both an endpoint and a tunnel key.
911 When the first such encapsulation is defined, we expect to add a
912 ``tunnel_key'' column to <ref table="Physical_Locator"/> to allow the
913 tunnel key to be defined.
917 See the ``Per Logical-Switch Tunnel Key'' section in the <ref
918 table="Logical_Switch"/> table for further discussion of the model.
921 <column name="encapsulation_type">
922 The type of tunneling encapsulation.
925 <column name="dst_ip">
927 For <code>vxlan_over_ipv4</code> encapsulation, the IPv4 address of the
928 VXLAN tunnel endpoint.
932 We expect that this column could be used for IPv4 or IPv6 addresses in
933 encapsulations to be introduced later.