From: Ben Pfaff Date: Tue, 29 Oct 2013 19:41:17 +0000 (-0700) Subject: vswitch.xml: Improve documentation for BFD. X-Git-Url: http://git.onelab.eu/?p=sliver-openvswitch.git;a=commitdiff_plain;h=e58855ec57e57498f5ddbe0baf6026f64e012415 vswitch.xml: Improve documentation for BFD. This update improves the BFD documentation in a few ways: - Demand mode is now supported. - Wordsmithing, spelling, etc. - Attempt to better explain decay_min_rx, forwarding_if_rx, and cpath_down. - Break into subgroups for configuration and status, to better explain which party sets which fields. - Reindents to match the rest of vswitch.xml. Because of the reindentation, this patch may be easier to view with spacing changes suppressed. Signed-off-by: Ben Pfaff --- diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml index c12fd8fc3..4ad0d63fa 100644 --- a/vswitchd/vswitch.xml +++ b/vswitchd/vswitch.xml @@ -1843,128 +1843,137 @@ -

- BFD, defined in RFC 5880 and RFC 5881, allows point to point - detection of connectivity failures by occasional transmission of - BFD control messages. It is implemented in Open vSwitch to serve - as a more popular and standards compliant alternative to CFM. -

- -

- BFD operates by regularly transmitting BFD control messages at a - rate negotiated independently in each direction. Each endpoint - specifies the rate at which it expects to receive control messages, - and the rate at which it's willing to transmit them. Open vSwitch - uses a detection multiplier of three, meaning that an endpoint - which fails to receive BFD control messages for a period of three - times the expected reception rate, will signal a connectivity - fault. In the case of a unidirectional connectivity issue, the - system not receiving BFD control messages will signal the problem - to its peer in the messages it transmits. -

- -

- The Open vSwitch implementation of BFD aims to comply faithfully - with the requirements put forth in RFC 5880. Currently, the only - known omission is ``Demand Mode'', which we hope to include in - future. Open vSwitch does not implement the optional - Authentication or ``Echo Mode'' features. -

- - - When true BFD is enabled on this - , otherwise it's disabled. Defaults to - false. - - - - The fastest rate, in milliseconds, at which this BFD session is - willing to receive BFD control messages. The actual rate may be - slower if the remote endpoint isn't willing to transmit as quickly as - specified. Defaults to 1000. - - - - The fastest 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 100. - - - - decay_min_rx is used to set the min_rx, - when there is no obvious incoming data traffic at the interface. - It cannot be set less than the min_rx. The decay feature - is disabled by setting the decay_min_rx to 0. And the - feature is reset everytime itself or min_rx is - reconfigured. - - - - When forwarding_if_rx is true the interface will be - considered capable of packet I/O as long as there is packet - received at interface. This is important in that when link becomes - temporarily conjested, consecutive BFD control packets can be lost. - And the forwarding_if_rx can prevent link failover by - detecting non-control packets received at interface. - - - - 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. When a controller thinks - this may be the case, it may set cpath_down to - true which may cause the remote BFD session not to - forward traffic to this . Defaults to - false. - - - - When set to true, Check Tunnel Key will make BFD only accept control - messages with an in_key of zero. Defaults to - false. - - - - An Ethernet address in the form - xx:xx:xx:xx:xx:xx - to set the destination mac address of the bfd packet. If this - field is set, it is assumed that all the bfd packets destined to this - interface also has the same destination mac address. If not set, a - default value of 00:23:20:00:00:01 is used. - - - - State of the BFD session. The BFD session is fully healthy and - negotiated if UP. - +

+ BFD, defined in RFC 5880 and RFC 5881, allows point-to-point + detection of connectivity failures by occasional transmission of + BFD control messages. Open vSwitch implements BFD to serve + as a more popular and standards compliant alternative to CFM. +

- - True if the BFD session believes this may be - used to forward traffic. Typically this means the local session is - signaling UP, and the remote system isn't signaling a - problem such as concatenated path down. - +

+ BFD operates by regularly transmitting BFD control messages at a rate + negotiated independently in each direction. Each endpoint specifies + the rate at which it expects to receive control messages, and the rate + at which it is willing to transmit them. Open vSwitch uses a detection + multiplier of three, meaning that an endpoint signals a connectivity + fault if three consecutive BFD control messages fail to arrive. In the + case of a unidirectional connectivity issue, the system not receiving + BFD control messages signals the problem to its peer in the messages it + transmits. +

- - A short message indicating what the BFD session thinks is wrong in - case of a problem. - +

+ The Open vSwitch implementation of BFD aims to comply faithfully + with RFC 5880 requirements. Open vSwitch does not implement the + optional Authentication or ``Echo Mode'' features. +

- - State of the remote endpoint's BFD session. - + +

+ A controller sets up key-value pairs in the + column to enable and configure BFD. +

+ + + True to enable BFD on this . + + + + 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 + 1000. + + + + 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 100. + + + + An alternate receive interval, in milliseconds, that must be greater + than or equal to . The + implementation switches from to 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 or + changes. + + + + 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. + + + + 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. + + + + 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. + + + + Set to an Ethernet address in the form + xx:xx:xx:xx:xx:xx + to set the MAC used as destination for transmitted BFD packets and + expected as destination for received BFD packets. The default is + 00:23:20:00:00:01. + + - - A short message indicating what the remote endpoint's BFD session - thinks is wrong in case of a problem. - + +

+ The switch sets key-value pairs in the + column to report the status of BFD on this interface. When BFD is + not enabled, with , the switch clears + all key-value pairs from . +

+ + + Reports the state of the BFD session. The BFD session is fully + healthy and negotiated if UP. + + + + Reports whether the BFD session believes this may be used to forward traffic. Typically this + means the local session is signaling UP, and the remote + system isn't signaling a problem such as concatenated path down. + + + + In case of a problem, set to a short message that reports what the + local BFD session thinks is wrong. + + + + Reports the state of the remote endpoint's BFD session. + + + + In case of a problem, set to a short message that reports what the + remote endpoint's BFD session thinks is wrong. + +