1 <database title="Open vSwitch Configuration Database">
2 <p>A database with this schema holds the configuration for one Open
3 vSwitch daemon. The root of the configuration for the daemon is
4 the <ref table="Open_vSwitch"/> table, which must have exactly one
5 record. Records in other tables are significant only when they
6 can be reached directly or indirectly from the
7 <ref table="Open_vSwitch"/> table.</p>
9 <table name="Open_vSwitch" title="Open vSwitch configuration.">
10 Configuration for an Open vSwitch daemon. There must be exactly one record
11 in the <ref table="Open_vSwitch"/> table.
13 <group title="Configuration">
14 <column name="bridges">
15 Set of bridges managed by the daemon.
18 <column name="managers">
19 Remote database clients to which the Open vSwitch's database server
20 should connect or to which it should listen.
24 SSL used globally by the daemon.
27 <column name="external_ids">
28 Key-value pairs for use by external frameworks that integrate
29 with Open vSwitch, rather than by Open vSwitch itself. System
30 integrators should either use the Open vSwitch development
31 mailing list to coordinate on common key-value definitions, or
32 choose key names that are likely to be unique. The currently
33 defined common key-value pairs are:
35 <dt><code>system-type</code></dt>
36 <dd>An identifier for the switch type, such as
37 <code>XenServer</code> or <code>KVM</code>.</dd>
38 <dt><code>system-version</code></dt>
39 <dd>The version of the switch software, such as
40 <code>5.6.0</code> on XenServer.</dd>
41 <dt><code>system-id</code></dt>
42 <dd>A unique identifier for the Open vSwitch's physical host.
43 The form of the identifier depends on the type of the host.
44 On a Citrix XenServer, this will likely be the same as
45 <code>xs-system-uuid</code>.</dd>
46 <dt><code>xs-system-uuid</code></dt>
47 <dd>The Citrix XenServer universally unique identifier for the
48 physical host as displayed by <code>xe host-list</code>.</dd>
53 <group title="Status">
54 <column name="next_cfg">
55 Sequence number for client to increment. When a client modifies
56 any part of the database configuration and wishes to wait for
57 Open vSwitch to finish applying the changes, it may increment
61 <column name="cur_cfg">
62 Sequence number that Open vSwitch sets to the current value of
63 <ref column="next_cfg"/> after it finishes applying a set of
64 configuration changes.
67 <column name="capabilities">
68 Describes functionality supported by the hardware and software platform
69 on which this Open vSwitch is based. Clients should not modify this
70 column. See the <ref table="Capability"/> description for defined
71 capability categories and the meaning of associated
72 <ref table="Capability"/> records.
75 <column name="statistics">
77 Key-value pairs that report statistics about a running Open_vSwitch
78 daemon. The current implementation updates these counters
79 periodically. In the future, we plan to, instead, update them only
80 when they are queried (e.g. using an OVSDB <code>select</code>
81 operation) and perhaps at other times, but not on any regular
84 The currently defined key-value pairs are listed below. Some Open
85 vSwitch implementations may not support some statistics, in which
86 case those key-value pairs are omitted.</p>
88 <dt><code>load-average</code></dt>
90 System load average multiplied by 100 and rounded to the nearest
99 Configuration for a bridge within an
100 <ref table="Open_vSwitch"/>.
103 A <ref table="Bridge"/> record represents an Ethernet switch with one or
104 more ``ports,'' which are the <ref table="Port"/> records pointed to by
105 the <ref table="Bridge"/>'s <ref column="ports"/> column.
108 <group title="Core Features">
110 Bridge identifier. Should be alphanumeric and no more than about 8
111 bytes long. Must be unique among the names of ports, interfaces, and
115 <column name="ports">
116 Ports included in the bridge.
119 <column name="mirrors">
120 Port mirroring configuration.
123 <column name="netflow">
124 NetFlow configuration.
127 <column name="sflow">
131 <column name="flood_vlans">
132 VLAN IDs of VLANs on which MAC address learning should be disabled, so
133 that packets are flooded instead of being sent to specific ports that
134 are believed to contain packets' destination MACs. This should
135 ordinarily be used to disable MAC learning on VLANs used for mirroring
136 (RSPAN VLANs). It may also be useful for debugging.
140 <group title="OpenFlow Configuration">
141 <column name="controller">
142 OpenFlow controller set. If unset, then no OpenFlow controllers
146 <column name="fail_mode">
147 <p>When a controller is configured, it is, ordinarily, responsible
148 for setting up all flows on the switch. Thus, if the connection to
149 the controller fails, no new network connections can be set up.
150 If the connection to the controller stays down long enough,
151 no packets can pass through the switch at all. This setting
152 determines the switch's response to such a situation. It may be set
153 to one of the following:
155 <dt><code>standalone</code></dt>
156 <dd>If no message is received from the controller for three
157 times the inactivity probe interval
158 (see <ref column="inactivity_probe"/>), then Open vSwitch
159 will take over responsibility for setting up flows. In
160 this mode, Open vSwitch causes the bridge to act like an
161 ordinary MAC-learning switch. Open vSwitch will continue
162 to retry connecting to the controller in the background
163 and, when the connection succeeds, it will discontinue its
164 standalone behavior.</dd>
165 <dt><code>secure</code></dt>
166 <dd>Open vSwitch will not set up flows on its own when the
167 controller connection fails or when no controllers are
168 defined. The bridge will continue to retry connecting to
169 any defined controllers forever.</dd>
172 <p>If this value is unset, the default is implementation-specific.</p>
173 <p>When more than one controller is configured,
174 <ref column="fail_mode"/> is considered only when none of the
175 configured controllers can be contacted.</p>
178 <column name="datapath_id">
179 Reports the OpenFlow datapath ID in use. Exactly 16 hex
180 digits. (Setting this column will have no useful effect. Set
181 <ref column="other_config"/>:<code>other-config</code>
186 <group title="Other Features">
187 <column name="datapath_type">
188 Name of datapath provider. The kernel datapath has
189 type <code>system</code>. The userspace datapath has
190 type <code>netdev</code>.
193 <column name="external_ids">
194 Key-value pairs for use by external frameworks that integrate
195 with Open vSwitch, rather than by Open vSwitch itself. System
196 integrators should either use the Open vSwitch development
197 mailing list to coordinate on common key-value definitions, or
198 choose key names that are likely to be unique. The currently
199 defined key-value pairs are:
201 <dt><code>bridge-id</code></dt>
202 <dd>A unique identifier of the bridge. On Citrix XenServer this
203 will commonly be the same as <code>xs-network-uuids</code>.</dd>
204 <dt><code>xs-network-uuids</code></dt>
205 <dd>Semicolon-delimited set of universally unique identifier(s) for
206 the network with which this bridge is associated on a Citrix
207 XenServer host. The network identifiers are RFC 4122 UUIDs as
208 displayed by, e.g., <code>xe network-list</code>.</dd>
212 <column name="other_config">
213 Key-value pairs for configuring rarely used bridge
214 features. The currently defined key-value pairs are:
216 <dt><code>datapath-id</code></dt>
218 digits to set the OpenFlow datapath ID to a specific
220 <dt><code>hwaddr</code></dt>
221 <dd>An Ethernet address in the form
222 <var>xx</var>:<var>xx</var>:<var>xx</var>:<var>xx</var>:<var>xx</var>:<var>xx</var>
223 to set the hardware address of the local port and influence the
230 <table name="Port" table="Port or bond configuration.">
231 <p>A port within a <ref table="Bridge"/>.</p>
232 <p>Most commonly, a port has exactly one ``interface,'' pointed to by its
233 <ref column="interfaces"/> column. Such a port logically
234 corresponds to a port on a physical Ethernet switch. A port
235 with more than one interface is a ``bonded port'' (see
236 <ref group="Bonding Configuration"/>).</p>
237 <p>Some properties that one might think as belonging to a port are actually
238 part of the port's <ref table="Interface"/> members.</p>
241 Port name. Should be alphanumeric and no more than about 8
242 bytes long. May be the same as the interface name, for
243 non-bonded ports. Must otherwise be unique among the names of
244 ports, interfaces, and bridges on a host.
247 <column name="interfaces">
248 The port's interfaces. If there is more than one, this is a
252 <group title="VLAN Configuration">
253 <p>A bridge port must be configured for VLANs in one of two
254 mutually exclusive ways:
256 <li>A ``trunk port'' has an empty value for <ref
257 column="tag"/>. Its <ref column="trunks"/> value may be
258 empty or non-empty.</li>
259 <li>An ``implicitly tagged VLAN port'' or ``access port''
260 has an nonempty value for <ref column="tag"/>. Its
261 <ref column="trunks"/> value must be empty.</li>
263 If <ref column="trunks"/> and <ref column="tag"/> are both
264 nonempty, the configuration is ill-formed.
269 If this is an access port (see above), the port's implicitly
270 tagged VLAN. Must be empty if this is a trunk port.
273 Frames arriving on trunk ports will be forwarded to this
274 port only if they are tagged with the given VLAN (or, if
275 <ref column="tag"/> is 0, then if they lack a VLAN header).
276 Frames arriving on other access ports will be forwarded to
277 this port only if they have the same <ref column="tag"/>
278 value. Frames forwarded to this port will not have an
282 When a frame with a 802.1Q header that indicates a nonzero
283 VLAN is received on an access port, it is discarded.
287 <column name="trunks">
289 If this is a trunk port (see above), the 802.1Q VLAN(s) that
290 this port trunks; if it is empty, then the port trunks all
291 VLANs. Must be empty if this is an access port.
294 Frames arriving on trunk ports are dropped if they are not
295 in one of the specified VLANs. For this purpose, packets
296 that have no VLAN header are treated as part of VLAN 0.
301 <group title="Bonding Configuration">
302 <p>A port that has more than one interface is a ``bonded port.''
303 Bonding allows for load balancing and fail-over. Open vSwitch
304 supports ``source load balancing'' (SLB) bonding, which
305 assigns flows to slaves based on source MAC address, with
306 periodic rebalancing as traffic patterns change. This form of
307 bonding does not require 802.3ad or other special support from
308 the upstream switch to which the slave devices are
311 <p>These columns apply only to bonded ports. Their values are
312 otherwise ignored.</p>
314 <column name="bond_updelay">
315 <p>For a bonded port, the number of milliseconds for which carrier must
316 stay up on an interface before the interface is considered to be up.
317 Specify <code>0</code> to enable the interface immediately.</p>
318 <p>This setting is honored only when at least one bonded interface is
319 already enabled. When no interfaces are enabled, then the first bond
320 interface to come up is enabled immediately.</p>
323 <column name="bond_downdelay">
324 For a bonded port, the number of milliseconds for which carrier must
325 stay down on an interface before the interface is considered to be
326 down. Specify <code>0</code> to disable the interface immediately.
329 <column name="bond_fake_iface">
330 For a bonded port, whether to create a fake internal interface with the
331 name of the port. Use only for compatibility with legacy software that
336 <group title="Other Features">
338 Quality of Service configuration for this port.
342 The MAC address to use for this port for the purpose of choosing the
343 bridge's MAC address. This column does not necessarily reflect the
344 port's actual MAC address, nor will setting it change the port's actual
348 <column name="fake_bridge">
349 Does this port represent a sub-bridge for its tagged VLAN within the
350 Bridge? See ovs-vsctl(8) for more information.
353 <column name="external_ids">
355 Key-value pairs for use by external frameworks that integrate with
356 Open vSwitch, rather than by Open vSwitch itself. System integrators
357 should either use the Open vSwitch development mailing list to
358 coordinate on common key-value definitions, or choose key names that
359 are likely to be unique.
362 No key-value pairs native to <ref table="Port"/> are currently
363 defined. For fake bridges (see the <ref column="fake_bridge"/>
364 column), external IDs for the fake bridge are defined here by
365 prefixing a <ref table="Bridge"/> <ref table="Bridge"
366 column="external_ids"/> key with <code>fake-bridge-</code>,
367 e.g. <code>fake-bridge-xs-network-uuids</code>.
371 <column name="other_config">
372 Key-value pairs for configuring rarely used port features. The
373 currently defined key-value pairs are:
375 <dt><code>hwaddr</code></dt>
376 <dd>An Ethernet address in the form
377 <code><var>xx</var>:<var>xx</var>:<var>xx</var>:<var>xx</var>:<var>xx</var>:<var>xx</var></code>.</dd>
378 <dt><code>bond-rebalance-interval</code></dt>
379 <dd>For a bonded port, the number of milliseconds between
380 successive attempts to rebalance the bond, that is, to
381 move source MACs and their flows from one interface on
382 the bond to another in an attempt to keep usage of each
383 interface roughly equal. The default is 10000 (10
384 seconds), and the minimum is 1000 (1 second).</dd>
390 <table name="Interface" title="One physical network device in a Port.">
391 An interface within a <ref table="Port"/>.
393 <group title="Core Features">
395 Interface name. Should be alphanumeric and no more than about 8 bytes
396 long. May be the same as the port name, for non-bonded ports. Must
397 otherwise be unique among the names of ports, interfaces, and bridges
402 <p>Ethernet address to set for this interface. If unset then the
403 default MAC address is used:</p>
405 <li>For the local interface, the default is the lowest-numbered MAC
406 address among the other bridge ports, either the value of the
407 <ref table="Port" column="mac"/> in its <ref table="Port"/> record,
408 if set, or its actual MAC (for bonded ports, the MAC of its slave
409 whose name is first in alphabetical order). Internal ports and
410 bridge ports that are used as port mirroring destinations (see the
411 <ref table="Mirror"/> table) are ignored.</li>
412 <li>For other internal interfaces, the default MAC is randomly
414 <li>External interfaces typically have a MAC address associated with
417 <p>Some interfaces may not have a software-controllable MAC
421 <column name="ofport">
422 <p>OpenFlow port number for this interface. Unlike most columns, this
423 column's value should be set only by Open vSwitch itself. Other
424 clients should set this column to an empty set (the default) when
425 creating an <ref table="Interface"/>.</p>
426 <p>Open vSwitch populates this column when the port number becomes
427 known. If the interface is successfully added,
428 <ref column="ofport"/> will be set to a number between 1 and 65535
429 (generally either in the range 1 to 65280, exclusive, or 65534, the
430 port number for the OpenFlow ``local port''). If the interface
431 cannot be added then Open vSwitch sets this column
436 <group title="System-Specific Details">
438 The interface type, one of:
440 <dt><code>system</code></dt>
441 <dd>An ordinary network device, e.g. <code>eth0</code> on Linux.
442 Sometimes referred to as ``external interfaces'' since they are
443 generally connected to hardware external to that on which the Open
444 vSwitch is running. The empty string is a synonym for
445 <code>system</code>.</dd>
446 <dt><code>internal</code></dt>
447 <dd>A simulated network device that sends and receives traffic. An
448 internal interface whose <ref column="name"/> is the same as its
449 bridge's <ref table="Open_vSwitch" column="name"/> is called the
450 ``local interface.'' It does not make sense to bond an internal
451 interface, so the terms ``port'' and ``interface'' are often used
452 imprecisely for internal interfaces.</dd>
453 <dt><code>tap</code></dt>
454 <dd>A TUN/TAP device managed by Open vSwitch.</dd>
455 <dt><code>gre</code></dt>
456 <dd>An Ethernet over RFC 2890 Generic Routing Encapsulation over IPv4
457 tunnel. Each tunnel must be uniquely identified by the
458 combination of <code>remote_ip</code>, <code>local_ip</code>, and
459 <code>in_key</code>. Note that if two ports are defined that are
460 the same except one has an optional identifier and the other does
461 not, the more specific one is matched first. <code>in_key</code>
462 is considered more specific than <code>local_ip</code> if a port
463 defines one and another port defines the other. The following
464 options may be specified in the <ref column="options"/> column:
466 <dt><code>remote_ip</code></dt>
467 <dd>Required. The tunnel endpoint.</dd>
470 <dt><code>local_ip</code></dt>
471 <dd>Optional. The destination IP that received packets must
472 match. Default is to match all addresses.</dd>
475 <dt><code>in_key</code></dt>
476 <dd>Optional. The GRE key that received packets must contain.
477 It may either be a 32-bit number (no key and a key of 0 are
478 treated as equivalent) or the word <code>flow</code>. If
479 <code>flow</code> is specified then any key will be accepted
480 and the key will be placed in the <code>tun_id</code> field
481 for matching in the flow table. The ovs-ofctl manual page
482 contains additional information about matching fields in
483 OpenFlow flows. Default is no key.</dd>
486 <dt><code>out_key</code></dt>
487 <dd>Optional. The GRE key to be set on outgoing packets. It may
488 either be a 32-bit number or the word <code>flow</code>. If
489 <code>flow</code> is specified then the key may be set using
490 the <code>set_tunnel</code> Nicira OpenFlow vendor extension (0
491 is used in the absence of an action). The ovs-ofctl manual
492 page contains additional information about the Nicira OpenFlow
493 vendor extensions. Default is no key.</dd>
496 <dt><code>key</code></dt>
497 <dd>Optional. Shorthand to set <code>in_key</code> and
498 <code>out_key</code> at the same time.</dd>
501 <dt><code>tos</code></dt>
502 <dd>Optional. The value of the ToS bits to be set on the
503 encapsulating packet. It may also be the word
504 <code>inherit</code>, in which case the ToS will be copied from
505 the inner packet if it is IPv4 or IPv6 (otherwise it will be
506 0). Note that the ECN fields are always inherited. Default is
510 <dt><code>ttl</code></dt>
511 <dd>Optional. The TTL to be set on the encapsulating packet.
512 It may also be the word <code>inherit</code>, in which case the
513 TTL will be copied from the inner packet if it is IPv4 or IPv6
514 (otherwise it will be the system default, typically 64).
515 Default is the system default TTL.</dd>
518 <dt><code>csum</code></dt>
519 <dd>Optional. Compute GRE checksums on outgoing packets.
520 Checksums present on incoming packets will be validated
521 regardless of this setting. Note that GRE checksums
522 impose a significant performance penalty as they cover the
523 entire packet. As the contents of the packet is typically
524 covered by L3 and L4 checksums, this additional checksum only
525 adds value for the GRE and encapsulated Ethernet headers.
526 Default is disabled, set to <code>true</code> to enable.</dd>
529 <dt><code>pmtud</code></dt>
530 <dd>Optional. Enable tunnel path MTU discovery. If enabled
531 ``ICMP destination unreachable - fragmentation'' needed
532 messages will be generated for IPv4 packets with the DF bit set
533 and IPv6 packets above the minimum MTU if the packet size
534 exceeds the path MTU minus the size of the tunnel headers. It
535 also forces the encapsulating packet DF bit to be set (it is
536 always set if the inner packet implies path MTU discovery).
537 Note that this option causes behavior that is typically
538 reserved for routers and therefore is not entirely in
539 compliance with the IEEE 802.1D specification for bridges.
540 Default is enabled, set to <code>false</code> to disable.</dd>
543 <dt><code>capwap</code></dt>
544 <dd>Ethernet tunneling over the UDP transport portion of CAPWAP
545 (RFC 5415). This allows interoperability with certain switches
546 where GRE is not available. Note that only the tunneling component
547 of the protocol is implemented. Due to the non-standard use of
548 CAPWAP, UDP ports 58881 and 58882 are used as the source and
549 destinations ports respectivedly. Each tunnel must be uniquely
550 identified by the combination of <code>remote_ip</code> and
551 <code>local_ip</code>. If two ports are defined that are the same
552 except one includes <code>local_ip</code> and the other does not,
553 the more specific one is matched first. CAPWAP support is not
554 available on all platforms. Currently it is only supported in the
555 Linux kernel module with kernel versions >= 2.6.25. The following
556 options may be specified in the <ref column="options"/> column:
558 <dt><code>remote_ip</code></dt>
559 <dd>Required. The tunnel endpoint.</dd>
562 <dt><code>local_ip</code></dt>
563 <dd>Optional. The destination IP that received packets must
564 match. Default is to match all addresses.</dd>
567 <dt><code>tos</code></dt>
568 <dd>Optional. The value of the ToS bits to be set on the
569 encapsulating packet. It may also be the word
570 <code>inherit</code>, in which case the ToS will be copied from
571 the inner packet if it is IPv4 or IPv6 (otherwise it will be
572 0). Note that the ECN fields are always inherited. Default is
576 <dt><code>ttl</code></dt>
577 <dd>Optional. The TTL to be set on the encapsulating packet.
578 It may also be the word <code>inherit</code>, in which case the
579 TTL will be copied from the inner packet if it is IPv4 or IPv6
580 (otherwise it will be the system default, typically 64).
581 Default is the system default TTL.</dd>
584 <dt><code>pmtud</code></dt>
585 <dd>Optional. Enable tunnel path MTU discovery. If enabled
586 ``ICMP destination unreachable - fragmentation'' needed
587 messages will be generated for IPv4 packets with the DF bit set
588 and IPv6 packets above the minimum MTU if the packet size
589 exceeds the path MTU minus the size of the tunnel headers. It
590 also forces the encapsulating packet DF bit to be set (it is
591 always set if the inner packet implies path MTU discovery).
592 Note that this option causes behavior that is typically
593 reserved for routers and therefore is not entirely in
594 compliance with the IEEE 802.1D specification for bridges.
595 Default is enabled, set to <code>false</code> to disable.</dd>
598 <dt><code>patch</code></dt>
601 A pair of virtual devices that act as a patch cable. The <ref
602 column="options"/> column must have the following key-value pair:
605 <dt><code>peer</code></dt>
607 The <ref column="name"/> of the <ref table="Interface"/> for
608 the other side of the patch. The named <ref
609 table="Interface"/>'s own <code>peer</code> option must specify
610 this <ref table="Interface"/>'s name. That is, the two patch
611 interfaces must have reversed <ref column="name"/> and
612 <code>peer</code> values.
619 <column name="options">
620 Configuration options whose interpretation varies based on
621 <ref column="type"/>.
624 <column name="status">
626 Key-value pairs that report port status. Supported status
627 values are <code>type</code>-dependent.
629 <p>The only currently defined key-value pair is:</p>
631 <dt><code>source_ip</code></dt>
632 <dd>The source IP address used for an IPv4 tunnel end-point,
633 such as <code>gre</code> or <code>capwap</code>. Not
634 supported by all implementations.</dd>
639 <group title="Ingress Policing">
640 <column name="ingress_policing_burst">
641 <p>Maximum burst size for data received on this interface, in kb. The
642 default burst size if set to <code>0</code> is 1000 kb. This value
643 has no effect if <ref column="ingress_policing_rate"/>
644 is <code>0</code>.</p>
645 <p>The burst size should be at least the size of the interface's
649 <column name="ingress_policing_rate">
650 <p>Maximum rate for data received on this interface, in kbps. Data
651 received faster than this rate is dropped. Set to <code>0</code> to
652 disable policing.</p>
653 <p>The meaning of ``ingress'' is from Open vSwitch's perspective. If
654 configured on a physical interface, then it limits the rate at which
655 traffic is allowed into the system from the outside. If configured
656 on a virtual interface that is connected to a virtual machine, then
657 it limits the rate at which the guest is able to transmit.</p>
661 <group title="Other Features">
662 <column name="external_ids">
663 Key-value pairs for use by external frameworks that integrate
664 with Open vSwitch, rather than by Open vSwitch itself. System
665 integrators should either use the Open vSwitch development
666 mailing list to coordinate on common key-value definitions, or
667 choose key names that are likely to be unique. The currently
668 defined common key-value pairs are:
670 <dt><code>attached-mac</code></dt>
672 The MAC address programmed into the ``virtual hardware'' for this
673 interface, in the form
674 <var>xx</var>:<var>xx</var>:<var>xx</var>:<var>xx</var>:<var>xx</var>:<var>xx</var>.
675 For Citrix XenServer, this is the value of the <code>MAC</code>
676 field in the VIF record for this interface.</dd>
677 <dt><code>iface-id</code></dt>
678 <dd>A system-unique identifier for the interface. On XenServer,
679 this will commonly be the same as <code>xs-vif-uuid</code>.</dd>
682 Additionally the following key-value pairs specifically
683 apply to an interface that represents a virtual Ethernet interface
684 connected to a virtual machine. These key-value pairs should not be
685 present for other types of interfaces. Keys whose names end
686 in <code>-uuid</code> have values that uniquely identify the entity
687 in question. For a Citrix XenServer hypervisor, these values are
688 UUIDs in RFC 4122 format. Other hypervisors may use other
691 <p>The currently defined key-value pairs for XenServer are:</p>
693 <dt><code>xs-vif-uuid</code></dt>
694 <dd>The virtual interface associated with this interface.</dd>
695 <dt><code>xs-network-uuid</code></dt>
696 <dd>The virtual network to which this interface is attached.</dd>
697 <dt><code>xs-vm-uuid</code></dt>
698 <dd>The VM to which this interface belongs.</dd>
702 <column name="statistics">
704 Key-value pairs that report interface statistics. The current
705 implementation updates these counters periodically. In the future,
706 we plan to, instead, update them when an interface is created, when
707 they are queried (e.g. using an OVSDB <code>select</code> operation),
708 and just before an interface is deleted due to virtual interface
709 hot-unplug or VM shutdown, and perhaps at other times, but not on any
710 regular periodic basis.</p>
712 The currently defined key-value pairs are listed below. These are
713 the same statistics reported by OpenFlow in its <code>struct
714 ofp_port_stats</code> structure. If an interface does not support a
715 given statistic, then that pair is omitted.</p>
718 Successful transmit and receive counters:
720 <dt><code>rx_packets</code></dt>
721 <dd>Number of received packets.</dd>
722 <dt><code>rx_bytes</code></dt>
723 <dd>Number of received bytes.</dd>
724 <dt><code>tx_packets</code></dt>
725 <dd>Number of transmitted packets.</dd>
726 <dt><code>tx_bytes</code></dt>
727 <dd>Number of transmitted bytes.</dd>
733 <dt><code>rx_dropped</code></dt>
734 <dd>Number of packets dropped by RX.</dd>
735 <dt><code>rx_frame_err</code></dt>
736 <dd>Number of frame alignment errors.</dd>
737 <dt><code>rx_over_err</code></dt>
738 <dd>Number of packets with RX overrun.</dd>
739 <dt><code>rx_crc_err</code></dt>
740 <dd>Number of CRC errors.</dd>
741 <dt><code>rx_errors</code></dt>
743 Total number of receive errors, greater than or equal
744 to the sum of the above.
751 <dt><code>tx_dropped</code></dt>
752 <dd>Number of packets dropped by TX.</dd>
753 <dt><code>collisions</code></dt>
754 <dd>Number of collisions.</dd>
755 <dt><code>tx_errors</code></dt>
757 Total number of transmit errors, greater
758 than or equal to the sum of the above.
767 <table name="QoS" title="Quality of Service configuration">
768 <p>Quality of Service (QoS) configuration for each Port that
772 <p>The type of QoS to implement. The <ref table="Open_vSwitch"
773 column="capabilities"/> column in the <ref table="Open_vSwitch"/> table
774 identifies the types that a switch actually supports. The currently
775 defined types are listed below:</p>
777 <dt><code>linux-htb</code></dt>
779 Linux ``hierarchy token bucket'' classifier. See tc-htb(8) (also at
780 <code>http://linux.die.net/man/8/tc-htb</code>) and the HTB manual
781 (<code>http://luxik.cdi.cz/~devik/qos/htb/manual/userg.htm</code>)
782 for information on how this classifier works and how to configure it.
787 <column name="queues">
788 <p>A map from queue numbers to <ref table="Queue"/> records. The
789 supported range of queue numbers depend on <ref column="type"/>. The
790 queue numbers are the same as the <code>queue_id</code> used in
791 OpenFlow in <code>struct ofp_action_enqueue</code> and other
792 structures. Queue 0 is used by OpenFlow output actions that do not
793 specify a specific queue.</p>
796 <column name="other_config">
797 <p>Key-value pairs for configuring QoS features that depend on
798 <ref column="type"/>.</p>
799 <p>The <code>linux-htb</code> class supports the following key-value
802 <dt><code>max-rate</code></dt>
803 <dd>Maximum rate shared by all queued traffic, in bit/s.
804 Optional. If not specified, for physical interfaces, the
805 default is the link rate. For other interfaces or if the
806 link rate cannot be determined, the default is currently 100
811 <column name="external_ids">
812 Key-value pairs for use by external frameworks that integrate with Open
813 vSwitch, rather than by Open vSwitch itself. System integrators should
814 either use the Open vSwitch development mailing list to coordinate on
815 common key-value definitions, or choose key names that are likely to be
816 unique. No common key-value pairs are currently defined.
820 <table name="Queue" title="QoS output queue.">
821 <p>A configuration for a port output queue, used in configuring Quality of
822 Service (QoS) features. May be referenced by <ref column="queues"
823 table="QoS"/> column in <ref table="QoS"/> table.</p>
825 <column name="other_config">
826 <p>Key-value pairs for configuring the output queue. The supported
827 key-value pairs and their meanings depend on the <ref column="type"/>
828 of the <ref column="QoS"/> records that reference this row.</p>
829 <p>The key-value pairs defined for <ref table="QoS"/> <ref table="QoS"
830 column="type"/> of <code>min-rate</code> are:</p>
832 <dt><code>min-rate</code></dt>
833 <dd>Minimum guaranteed bandwidth, in bit/s. Required.</dd>
835 <p>The key-value pairs defined for <ref table="QoS"/> <ref table="QoS"
836 column="type"/> of <code>linux-htb</code> are:</p>
838 <dt><code>min-rate</code></dt>
839 <dd>Minimum guaranteed bandwidth, in bit/s. Required.</dd>
840 <dt><code>max-rate</code></dt>
841 <dd>Maximum allowed bandwidth, in bit/s. Optional. If specified, the
842 queue's rate will not be allowed to exceed the specified value, even
843 if excess bandwidth is available. If unspecified, defaults to no
845 <dt><code>burst</code></dt>
846 <dd>Burst size, in bits. This is the maximum amount of ``credits''
847 that a queue can accumulate while it is idle. Optional. Details of
848 the <code>linux-htb</code> implementation require a minimum burst
849 size, so a too-small <code>burst</code> will be silently
851 <dt><code>priority</code></dt>
852 <dd>A nonnegative 32-bit integer. Defaults to 0 if
853 unspecified. A queue with a smaller <code>priority</code>
854 will receive all the excess bandwidth that it can use before
855 a queue with a larger value receives any. Specific priority
856 values are unimportant; only relative ordering matters.</dd>
860 <column name="external_ids">
861 Key-value pairs for use by external frameworks that integrate with Open
862 vSwitch, rather than by Open vSwitch itself. System integrators should
863 either use the Open vSwitch development mailing list to coordinate on
864 common key-value definitions, or choose key names that are likely to be
865 unique. No common key-value pairs are currently defined.
869 <table name="Mirror" title="Port mirroring (SPAN/RSPAN).">
870 <p>A port mirror within a <ref table="Bridge"/>.</p>
871 <p>A port mirror configures a bridge to send selected frames to special
872 ``mirrored'' ports, in addition to their normal destinations. Mirroring
873 traffic may also be referred to as SPAN or RSPAN, depending on the
874 mechanism used for delivery.</p>
877 Arbitrary identifier for the <ref table="Mirror"/>.
880 <group title="Selecting Packets for Mirroring">
881 <column name="select_all">
882 If true, every packet arriving or departing on any port is
883 selected for mirroring.
886 <column name="select_dst_port">
887 Ports on which departing packets are selected for mirroring.
890 <column name="select_src_port">
891 Ports on which arriving packets are selected for mirroring.
894 <column name="select_vlan">
895 VLANs on which packets are selected for mirroring. An empty set
896 selects packets on all VLANs.
900 <group title="Mirroring Destination Configuration">
901 <column name="output_port">
902 <p>Output port for selected packets, if nonempty. Mutually exclusive
903 with <ref column="output_vlan"/>.</p>
904 <p>Specifying a port for mirror output reserves that port exclusively
905 for mirroring. No frames other than those selected for mirroring
906 will be forwarded to the port, and any frames received on the port
907 will be discarded.</p>
908 <p>This type of mirroring is sometimes called SPAN.</p>
911 <column name="output_vlan">
912 <p>Output VLAN for selected packets, if nonempty. Mutually exclusive
913 with <ref column="output_port"/>.</p>
914 <p>The frames will be sent out all ports that trunk
915 <ref column="output_vlan"/>, as well as any ports with implicit VLAN
916 <ref column="output_vlan"/>. When a mirrored frame is sent out a
917 trunk port, the frame's VLAN tag will be set to
918 <ref column="output_vlan"/>, replacing any existing tag; when it is
919 sent out an implicit VLAN port, the frame will not be tagged. This
920 type of mirroring is sometimes called RSPAN.</p>
921 <p><em>Please note:</em> Mirroring to a VLAN can disrupt a network that
922 contains unmanaged switches. Consider an unmanaged physical switch
923 with two ports: port 1, connected to an end host, and port 2,
924 connected to an Open vSwitch configured to mirror received packets
925 into VLAN 123 on port 2. Suppose that the end host sends a packet on
926 port 1 that the physical switch forwards to port 2. The Open vSwitch
927 forwards this packet to its destination and then reflects it back on
928 port 2 in VLAN 123. This reflected packet causes the unmanaged
929 physical switch to replace the MAC learning table entry, which
930 correctly pointed to port 1, with one that incorrectly points to port
931 2. Afterward, the physical switch will direct packets destined for
932 the end host to the Open vSwitch on port 2, instead of to the end
933 host on port 1, disrupting connectivity. If mirroring to a VLAN is
934 desired in this scenario, then the physical switch must be replaced
935 by one that learns Ethernet addresses on a per-VLAN basis. In
936 addition, learning should be disabled on the VLAN containing mirrored
937 traffic. If this is not done then intermediate switches will learn
938 the MAC address of each end host from the mirrored traffic. If
939 packets being sent to that end host are also mirrored, then they will
940 be dropped since the switch will attempt to send them out the input
941 port. Disabling learning for the VLAN will cause the switch to
942 correctly send the packet out all ports configured for that VLAN. If
943 Open vSwitch is being used as an intermediate switch, learning can be
944 disabled by adding the mirrored VLAN to <ref column="flood_vlans"/>
945 in the appropriate <ref table="Bridge"/> table or tables.</p>
949 <group title="Other Features">
950 <column name="external_ids">
951 Key-value pairs for use by external frameworks that integrate with Open
952 vSwitch, rather than by Open vSwitch itself. System integrators should
953 either use the Open vSwitch development mailing list to coordinate on
954 common key-value definitions, or choose key names that are likely to be
955 unique. No common key-value pairs are currently defined.
960 <table name="Controller" title="OpenFlow controller configuration.">
961 <p>An OpenFlow controller.</p>
964 Open vSwitch supports two kinds of OpenFlow controllers:
968 <dt>Primary controllers</dt>
971 This is the kind of controller envisioned by the OpenFlow 1.0
972 specification. Usually, a primary controller implements a network
973 policy by taking charge of the switch's flow table.
977 Open vSwitch initiates and maintains persistent connections to
978 primary controllers, retrying the connection each time it fails or
979 drops. The <ref table="Bridge" column="fail_mode"/> column in the
980 <ref table="Bridge"/> table applies to primary controllers.
984 Open vSwitch permits a bridge to have any number of primary
985 controllers. When multiple controllers are configured, Open
986 vSwitch connects to all of them simultaneously. Because
987 OpenFlow 1.0 does not specify how multiple controllers
988 coordinate in interacting with a single switch, more than
989 one primary controller should be specified only if the
990 controllers are themselves designed to coordinate with each
991 other. (The Nicira-defined <code>NXT_ROLE</code> OpenFlow
992 vendor extension may be useful for this.)
995 <dt>Service controllers</dt>
998 These kinds of OpenFlow controller connections are intended for
999 occasional support and maintenance use, e.g. with
1000 <code>ovs-ofctl</code>. Usually a service controller connects only
1001 briefly to inspect or modify some of a switch's state.
1005 Open vSwitch listens for incoming connections from service
1006 controllers. The service controllers initiate and, if necessary,
1007 maintain the connections from their end. The <ref table="Bridge"
1008 column="fail_mode"/> column in the <ref table="Bridge"/> table does
1009 not apply to service controllers.
1013 Open vSwitch supports configuring any number of service controllers.
1019 The <ref column="target"/> determines the type of controller.
1022 <group title="Core Features">
1023 <column name="target">
1024 <p>Connection method for controller.</p>
1026 The following connection methods are currently supported for primary
1030 <dt><code>ssl:<var>ip</var></code>[<code>:<var>port</var></code>]</dt>
1032 <p>The specified SSL <var>port</var> (default: 6633) on the host at
1033 the given <var>ip</var>, which must be expressed as an IP address
1034 (not a DNS name). The <ref table="Open_vSwitch" column="ssl"/>
1035 column in the <ref table="Open_vSwitch"/> table must point to a
1036 valid SSL configuration when this form is used.</p>
1037 <p>SSL support is an optional feature that is not always built as
1038 part of Open vSwitch.</p>
1040 <dt><code>tcp:<var>ip</var></code>[<code>:<var>port</var></code>]</dt>
1041 <dd>The specified TCP <var>port</var> (default: 6633) on the host at
1042 the given <var>ip</var>, which must be expressed as an IP address
1043 (not a DNS name).</dd>
1044 <dt><code>discover</code></dt>
1046 <p>Enables controller discovery.</p>
1047 <p>In controller discovery mode, Open vSwitch broadcasts a DHCP
1048 request with vendor class identifier <code>OpenFlow</code> across
1049 all of the bridge's network devices. It will accept any valid
1050 DHCP reply that has the same vendor class identifier and includes
1051 a vendor-specific option with code 1 whose contents are a string
1052 specifying the location of the controller in the same format as
1053 <ref column="target"/>.</p>
1054 <p>The DHCP reply may also, optionally, include a vendor-specific
1055 option with code 2 whose contents are a string specifying the URI
1056 to the base of the OpenFlow PKI
1057 (e.g. <code>http://192.168.0.1/openflow/pki</code>). This URI is
1058 used only for bootstrapping the OpenFlow PKI at initial switch
1059 setup; <code>ovs-vswitchd</code> does not use it at all.</p>
1063 The following connection methods are currently supported for service
1067 <dt><code>pssl:</code>[<var>port</var>][<code>:<var>ip</var></code>]</dt>
1070 Listens for SSL connections on the specified TCP <var>port</var>
1071 (default: 6633). If <var>ip</var>, which must be expressed as an
1072 IP address (not a DNS name), is specified, then connections are
1073 restricted to the specified local IP address.
1076 The <ref table="Open_vSwitch" column="ssl"/> column in the <ref
1077 table="Open_vSwitch"/> table must point to a valid SSL
1078 configuration when this form is used.
1080 <p>SSL support is an optional feature that is not always built as
1081 part of Open vSwitch.</p>
1083 <dt><code>ptcp:</code>[<var>port</var>][<code>:<var>ip</var></code>]</dt>
1085 Listens for connections on the specified TCP <var>port</var>
1086 (default: 6633). If <var>ip</var>, which must be expressed as an
1087 IP address (not a DNS name), is specified, then connections are
1088 restricted to the specified local IP address.
1091 <p>When multiple controllers are configured for a single bridge, the
1092 <ref column="target"/> values must be unique. Duplicate
1093 <ref column="target"/> values yield unspecified results.</p>
1096 <column name="connection_mode">
1097 <p>If it is specified, this setting must be one of the following
1098 strings that describes how Open vSwitch contacts this OpenFlow
1099 controller over the network:</p>
1102 <dt><code>in-band</code></dt>
1103 <dd>In this mode, this controller's OpenFlow traffic travels over the
1104 bridge associated with the controller. With this setting, Open
1105 vSwitch allows traffic to and from the controller regardless of the
1106 contents of the OpenFlow flow table. (Otherwise, Open vSwitch
1107 would never be able to connect to the controller, because it did
1108 not have a flow to enable it.) This is the most common connection
1109 mode because it is not necessary to maintain two independent
1111 <dt><code>out-of-band</code></dt>
1112 <dd>In this mode, OpenFlow traffic uses a control network separate
1113 from the bridge associated with this controller, that is, the
1114 bridge does not use any of its own network devices to communicate
1115 with the controller. The control network must be configured
1116 separately, before or after <code>ovs-vswitchd</code> is started.
1120 <p>If not specified, the default is implementation-specific. If
1121 <ref column="target"/> is <code>discover</code>, the connection mode
1122 is always treated as <code>in-band</code> regardless of the actual
1127 <group title="Controller Failure Detection and Handling">
1128 <column name="max_backoff">
1129 Maximum number of milliseconds to wait between connection attempts.
1130 Default is implementation-specific.
1133 <column name="inactivity_probe">
1134 Maximum number of milliseconds of idle time on connection to
1135 controller before sending an inactivity probe message. If Open
1136 vSwitch does not communicate with the controller for the specified
1137 number of seconds, it will send a probe. If a response is not
1138 received for the same additional amount of time, Open vSwitch
1139 assumes the connection has been broken and attempts to reconnect.
1140 Default is implementation-specific.
1144 <group title="OpenFlow Rate Limiting">
1145 <column name="controller_rate_limit">
1146 <p>The maximum rate at which packets in unknown flows will be
1147 forwarded to the OpenFlow controller, in packets per second. This
1148 feature prevents a single bridge from overwhelming the controller.
1149 If not specified, the default is implementation-specific.</p>
1150 <p>In addition, when a high rate triggers rate-limiting, Open
1151 vSwitch queues controller packets for each port and transmits
1152 them to the controller at the configured rate. The number of
1153 queued packets is limited by
1154 the <ref column="controller_burst_limit"/> value. The packet
1155 queue is shared fairly among the ports on a bridge.</p><p>Open
1156 vSwitch maintains two such packet rate-limiters per bridge.
1157 One of these applies to packets sent up to the controller
1158 because they do not correspond to any flow. The other applies
1159 to packets sent up to the controller by request through flow
1160 actions. When both rate-limiters are filled with packets, the
1161 actual rate that packets are sent to the controller is up to
1162 twice the specified rate.</p>
1165 <column name="controller_burst_limit">
1166 In conjunction with <ref column="controller_rate_limit"/>,
1167 the maximum number of unused packet credits that the bridge will
1168 allow to accumulate, in packets. If not specified, the default
1169 is implementation-specific.
1173 <group title="Additional Discovery Configuration">
1174 <p>These values are considered only when <ref column="target"/>
1175 is <code>discover</code>.</p>
1177 <column name="discover_accept_regex">
1179 extended regular expression against which the discovered controller
1180 location is validated. The regular expression is implicitly
1181 anchored at the beginning of the controller location string, as
1182 if it begins with <code>^</code>. If not specified, the default
1183 is implementation-specific.
1186 <column name="discover_update_resolv_conf">
1187 Whether to update <code>/etc/resolv.conf</code> when the
1188 controller is discovered. If not specified, the default
1189 is implementation-specific. Open vSwitch will only modify
1190 <code>/etc/resolv.conf</code> if the DHCP response that it receives
1191 specifies one or more DNS servers.
1195 <group title="Additional In-Band Configuration">
1196 <p>These values are considered only in in-band control mode (see
1197 <ref column="connection_mode"/>) and only when <ref column="target"/>
1198 is not <code>discover</code>. (For controller discovery, the network
1199 configuration obtained via DHCP is used instead.)</p>
1201 <p>When multiple controllers are configured on a single bridge, there
1202 should be only one set of unique values in these columns. If different
1203 values are set for these columns in different controllers, the effect
1206 <column name="local_ip">
1207 The IP address to configure on the local port,
1208 e.g. <code>192.168.0.123</code>. If this value is unset, then
1209 <ref column="local_netmask"/> and <ref column="local_gateway"/> are
1213 <column name="local_netmask">
1214 The IP netmask to configure on the local port,
1215 e.g. <code>255.255.255.0</code>. If <ref column="local_ip"/> is set
1216 but this value is unset, then the default is chosen based on whether
1217 the IP address is class A, B, or C.
1220 <column name="local_gateway">
1221 The IP address of the gateway to configure on the local port, as a
1222 string, e.g. <code>192.168.0.1</code>. Leave this column unset if
1223 this network has no gateway.
1227 <group title="Other Features">
1228 <column name="external_ids">
1229 Key-value pairs for use by external frameworks that integrate with Open
1230 vSwitch, rather than by Open vSwitch itself. System integrators should
1231 either use the Open vSwitch development mailing list to coordinate on
1232 common key-value definitions, or choose key names that are likely to be
1233 unique. No common key-value pairs are currently defined.
1238 <table name="NetFlow">
1239 A NetFlow target. NetFlow is a protocol that exports a number of
1240 details about terminating IP flows, such as the principals involved
1243 <column name="targets">
1244 NetFlow targets in the form
1245 <code><var>ip</var>:<var>port</var></code>. The <var>ip</var>
1246 must be specified numerically, not as a DNS name.
1249 <column name="engine_id">
1250 Engine ID to use in NetFlow messages. Defaults to datapath index
1254 <column name="engine_type">
1255 Engine type to use in NetFlow messages. Defaults to datapath
1256 index if not specified.
1259 <column name="active_timeout">
1260 The interval at which NetFlow records are sent for flows that are
1261 still active, in seconds. A value of <code>0</code> requests the
1262 default timeout (currently 600 seconds); a value of <code>-1</code>
1263 disables active timeouts.
1266 <column name="add_id_to_interface">
1267 <p>If this column's value is <code>false</code>, the ingress and egress
1268 interface fields of NetFlow flow records are derived from OpenFlow port
1269 numbers. When it is <code>true</code>, the 7 most significant bits of
1270 these fields will be replaced by the least significant 7 bits of the
1271 engine id. This is useful because many NetFlow collectors do not
1272 expect multiple switches to be sending messages from the same host, so
1273 they do not store the engine information which could be used to
1274 disambiguate the traffic.</p>
1275 <p>When this option is enabled, a maximum of 508 ports are supported.</p>
1278 <column name="external_ids">
1279 Key-value pairs for use by external frameworks that integrate with Open
1280 vSwitch, rather than by Open vSwitch itself. System integrators should
1281 either use the Open vSwitch development mailing list to coordinate on
1282 common key-value definitions, or choose key names that are likely to be
1283 unique. No common key-value pairs are currently defined.
1288 SSL configuration for an Open_vSwitch.
1290 <column name="private_key">
1291 Name of a PEM file containing the private key used as the switch's
1292 identity for SSL connections to the controller.
1295 <column name="certificate">
1296 Name of a PEM file containing a certificate, signed by the
1297 certificate authority (CA) used by the controller and manager,
1298 that certifies the switch's private key, identifying a trustworthy
1302 <column name="ca_cert">
1303 Name of a PEM file containing the CA certificate used to verify
1304 that the switch is connected to a trustworthy controller.
1307 <column name="bootstrap_ca_cert">
1308 If set to <code>true</code>, then Open vSwitch will attempt to
1309 obtain the CA certificate from the controller on its first SSL
1310 connection and save it to the named PEM file. If it is successful,
1311 it will immediately drop the connection and reconnect, and from then
1312 on all SSL connections must be authenticated by a certificate signed
1313 by the CA certificate thus obtained. <em>This option exposes the
1314 SSL connection to a man-in-the-middle attack obtaining the initial
1315 CA certificate.</em> It may still be useful for bootstrapping.
1318 <column name="external_ids">
1319 Key-value pairs for use by external frameworks that integrate with Open
1320 vSwitch, rather than by Open vSwitch itself. System integrators should
1321 either use the Open vSwitch development mailing list to coordinate on
1322 common key-value definitions, or choose key names that are likely to be
1323 unique. No common key-value pairs are currently defined.
1327 <table name="sFlow">
1328 <p>An sFlow(R) target. sFlow is a protocol for remote monitoring
1331 <column name="agent">
1332 Name of the network device whose IP address should be reported as the
1333 ``agent address'' to collectors. If not specified, the IP address
1334 defaults to the <ref table="Controller" column="local_ip"/> in the
1335 collector's <ref table="Controller"/>. If an agent IP address cannot be
1336 determined either way, sFlow is disabled.
1339 <column name="header">
1340 Number of bytes of a sampled packet to send to the collector.
1341 If not specified, the default is 128 bytes.
1344 <column name="polling">
1345 Polling rate in seconds to send port statistics to the collector.
1346 If not specified, defaults to 30 seconds.
1349 <column name="sampling">
1350 Rate at which packets should be sampled and sent to the collector.
1351 If not specified, defaults to 400, which means one out of 400
1352 packets, on average, will be sent to the collector.
1355 <column name="targets">
1356 sFlow targets in the form
1357 <code><var>ip</var>:<var>port</var></code>.
1360 <column name="external_ids">
1361 Key-value pairs for use by external frameworks that integrate with Open
1362 vSwitch, rather than by Open vSwitch itself. System integrators should
1363 either use the Open vSwitch development mailing list to coordinate on
1364 common key-value definitions, or choose key names that are likely to be
1365 unique. No common key-value pairs are currently defined.
1369 <table name="Capability">
1370 <p>Records in this table describe functionality supported by the hardware
1371 and software platform on which this Open vSwitch is based. Clients
1372 should not modify this table.</p>
1374 <p>A record in this table is meaningful only if it is referenced by the
1375 <ref table="Open_vSwitch" column="capabilities"/> column in the
1376 <ref table="Open_vSwitch"/> table. The key used to reference it, called
1377 the record's ``category,'' determines the meanings of the
1378 <ref column="details"/> column. The following general forms of
1379 categories are currently defined:</p>
1382 <dt><code>qos-<var>type</var></code></dt>
1383 <dd><var>type</var> is supported as the value for
1384 <ref column="type" table="QoS"/> in the <ref table="QoS"/> table.
1388 <column name="details">
1389 <p>Key-value pairs that describe capabilities. The meaning of the pairs
1390 depends on the category key that the <ref table="Open_vSwitch"
1391 column="capabilities"/> column in the <ref table="Open_vSwitch"/> table
1392 uses to reference this record, as described above.</p>
1394 <p>The presence of a record for category <code>qos-<var>type</var></code>
1395 indicates that the switch supports <var>type</var> as the value of
1396 the <ref table="QoS" column="type"/> column in the <ref table="QoS"/>
1397 table. The following key-value pairs are defined to further describe
1398 QoS capabilities:</p>
1401 <dt><code>n-queues</code></dt>
1402 <dd>Number of supported queues, as a positive integer. Keys in the
1403 <ref table="QoS" column="queues"/> column for <ref table="QoS"/>
1404 records whose <ref table="QoS" column="type"/> value
1405 equals <var>type</var> must range between 0 and this value minus one,