- <column name="bfd" key="min_rx">
- The minimum rate, in milliseconds, at which this BFD session is
- willing to receive BFD control messages. The actual rate may slower
- if the remote endpoint isn't willing to transmit as quickly as
- specified. Defaults to <code>1000</code>.
- </column>
-
- <column name="bfd" key="min_tx">
- The minimum rate, in milliseconds, at which this BFD session is
- willing to transmit BFD control messages. The actual rate may be
- slower if the remote endpoint isn't willing to receive as quickly as
- specified. Defaults to <code>100</code>.
- </column>
-
- <column name="bfd" key="cpath_down">
- Concatenated path down may be used when the local system should not
- have traffic forwarded to it for some reason other than a connectivty
- failure on the interface being monitored. The local BFD session will
- notify the remote session of the connectivity problem, at which time
- the remote session may choose not to forward traffic. Defaults to
- <code>false</code>.
- </column>
-
- <column name="bfd_status" key="state">
- State of the BFD session. One of <code>ADMIN_DOWN</code>,
- <code>DOWN</code>, <code>INIT</code>, or <code>UP</code>.
- </column>
-
- <column name="bfd_status" key="forwarding">
- True if the BFD session believes this <ref table="Physical_Locator"/> may be
- used to forward traffic. Typically this means the local session is
- up, and the remote system isn't signalling a problem such as
- concatenated path down.
- </column>
-
- <column name="bfd_status" key="diagnostic">
- A short message indicating what the BFD session thinks is wrong in
- case of a problem.
- </column>
-
- <column name="bfd_status" key="remote state">
- State of the remote endpoint's BFD session.
- </column>
-
- <column name="bfd_status" key="remote diagnostic">
- A short message indicating what the remote endpoint's BFD session
- thinks is wrong in case of a problem.
- </column>
+ <p>
+ A hardware VTEP is expected to use BFD to determine reachability of
+ devices at the end of the tunnels with which it exchanges data. This
+ can enable the VTEP to choose a functioning service node among a set of
+ service nodes providing high availability. It also enables the NVC to
+ report the health status of tunnels.
+ </p>
+
+ <p>
+ In most cases the BFD peer of a hardware VTEP will be an Open vSwitch
+ instance. The Open vSwitch implementation of BFD aims to comply
+ faithfully with the requirements put forth in RFC 5880. Open vSwitch
+ does not implement the optional Authentication or ``Echo Mode''
+ features.
+ </p>
+
+ <group title="BFD Configuration">
+ <p>
+ A controller sets up key-value pairs in the <ref column="bfd"/>
+ column to enable and configure BFD.
+ </p>
+
+ <column name="bfd" key="enable" type='{"type": "boolean"}'>
+ True to enable BFD on this <ref table="Physical_Locator"/>.
+ </column>
+
+ <column name="bfd" key="min_rx"
+ type='{"type": "integer", "minInteger": 1}'>
+ The shortest interval, in milliseconds, at which this BFD session
+ offers to receive BFD control messages. The remote endpoint may
+ choose to send messages at a slower rate. Defaults to
+ <code>1000</code>.
+ </column>
+
+ <column name="bfd" key="min_tx"
+ type='{"type": "integer", "minInteger": 1}'>
+ The shortest interval, in milliseconds, at which this BFD session is
+ willing to transmit BFD control messages. Messages will actually be
+ transmitted at a slower rate if the remote endpoint is not willing to
+ receive as quickly as specified. Defaults to <code>100</code>.
+ </column>
+
+ <column name="bfd" key="decay_min_rx" type='{"type": "integer"}'>
+ An alternate receive interval, in milliseconds, that must be greater
+ than or equal to <ref column="bfd" key="min_rx"/>. The
+ implementation switches from <ref column="bfd" key="min_rx"/> to <ref
+ column="bfd" key="decay_min_rx"/> when there is no obvious incoming
+ data traffic at the interface, to reduce the CPU and bandwidth cost
+ of monitoring an idle interface. This feature may be disabled by
+ setting a value of 0. This feature is reset whenever <ref
+ column="bfd" key="decay_min_rx"/> or <ref column="bfd" key="min_rx"/>
+ changes.
+ </column>
+
+ <column name="bfd" key="forwarding_if_rx" type='{"type": "boolean"}'>
+ True to consider the interface capable of packet I/O as long as it
+ continues to receive any packets (not just BFD packets). This
+ prevents link congestion that causes consecutive BFD control packets
+ to be lost from marking the interface down.
+ </column>
+
+ <column name="bfd" key="cpath_down" type='{"type": "boolean"}'>
+ Set to true to notify the remote endpoint that traffic should not be
+ forwarded to this system for some reason other than a connectivty
+ failure on the interface being monitored. The typical underlying
+ reason is ``concatenated path down,'' that is, that connectivity
+ beyond the local system is down. Defaults to false.
+ </column>
+
+ <column name="bfd" key="check_tnl_key" type='{"type": "boolean"}'>
+ Set to true to make BFD accept only control messages with a tunnel
+ key of zero. By default, BFD accepts control messages with any
+ tunnel key.
+ </column>
+
+ <column name="bfd" key="bfd_dst_mac">
+ Set to an Ethernet address in the form
+ <var>xx</var>:<var>xx</var>:<var>xx</var>:<var>xx</var>:<var>xx</var>:<var>xx</var>
+ to set the MAC used as destination for transmitted BFD packets and
+ expected as destination for received BFD packets. The default is
+ <code>00:23:20:00:00:01</code>.
+ </column>
+ </group>
+
+ <group title="BFD Status">
+ <p>
+ The VTEP sets key-value pairs in the <ref column="bfd_status"/>
+ column to report the status of BFD on this interface. When BFD is
+ not enabled, with <ref column="bfd" key="enable"/>, the switch clears
+ all key-value pairs from <ref column="bfd_status"/>.
+ </p>
+
+ <column name="bfd_status" key="state"
+ type='{"type": "string",
+ "enum": ["set", ["admin_down", "down", "init", "up"]]}'>
+ Reports the state of the BFD session. The BFD session is fully
+ healthy and negotiated if <code>UP</code>.
+ </column>
+
+ <column name="bfd_status" key="forwarding" type='{"type": "boolean"}'>
+ Reports whether the BFD session believes this <ref
+ table="Physical_Locator"/> may be used to forward traffic. Typically
+ this means the local session is signaling <code>UP</code>, and the
+ remote system isn't signaling a problem such as concatenated path
+ down.
+ </column>
+
+ <column name="bfd_status" key="diagnostic">
+ In case of a problem, set to a short message that reports what the
+ local BFD session thinks is wrong.
+ </column>
+
+ <column name="bfd_status" key="remote_state"
+ type='{"type": "string",
+ "enum": ["set", ["admin_down", "down", "init", "up"]]}'>
+ Reports the state of the remote endpoint's BFD session.
+ </column>
+
+ <column name="bfd_status" key="remote_diagnostic">
+ In case of a problem, set to a short message that reports what the
+ remote endpoint's BFD session thinks is wrong.
+ </column>
+ </group>