There is a list of necessary elements to know when forging a BGP configuration.
When forging a BFD configuration, the
destination IP and the kind of
BFD variant determine a BFD session.
tracker bfd main type single-hop address 10.125.0.2 vrf main
Three additional parameters determine the BFD session: the
interface name and the
vrf name. The
permit to stick with routing constraints.
tracker bfd other type single-hop address 10.125.0.2 source 10.125.0.1 vrf main
BFD provides low overhead. However, it provides a per peer custom configuration, that permits lowering (or increasing) the timers that determine how, and when BFD packets are sent, and received.
tracker bfd othername type single-hop address 10.125.0.2 vrf main detection-multiplier 6 required-receive-interval 600000 desired-transmission-interval 600000
It is possible to disable bfd session usage, by using following command. Note that you will have to check that no other daemon is using BFD. Otherwise, the command will not be successful.
del tracker bfd othername
It is possible to change general timer settings that will apply to the BFD sessions automatically created by routing protocols (like BGP). This facility avoids the heavy task to configure for each session the newly wished parameters. Note that configured values are expressed in microseconds.
routing bfd detection-multiplier 7 required-receive-interval 800000 desired-transmission-interval 200000
Reversely, it is possible to revert to default settings. By default, detect multiplier is set to 3, while default required-receive-interval and transmit-interval is set to 300 milliseconds.
routing bfd del detection-multiplier del required-receive-interval del desired-transmission-interval
You can use the
show bfd commands to watch for BFD sessions.
Following commands gives detailed BFD information about the BFD sessions status and statistics.
vrouter> show bfd vrf main session single-hop destination 10.125.0.2 peer 10.125.0.2 singlehop local-address 10.125.0.1 ID: 2916604864 Remote ID: 1159562547 Status: up Uptime: 37 second(s) Diagnostics: ok Remote diagnostics: ok Local timers: Receive interval: 300ms Transmission interval: 300ms Echo transmission interval: 50ms Remote timers: Receive interval: 300ms Transmission interval: 300ms Echo transmission interval: 50ms
vrouter> show bfd vrf main sessions counters BFD Peers: peer 10.125.0.2 singlehop local-address 10.125.0.1 Control packet input: 182 packets Control packet output: 181 packets Echo packet input: 0 packets Echo packet output: 0 packets Session up events: 1 Session down events: 0 Zebra notifications: 2
In addition to be able to create BFD peer sessions by using nc-cli of bfd, it is possible to dynamically create BFD peer sessions by relying on remote daemons.