Concept Guide

• If other destination prexes in the prex-list are pointing to the same neighbor, then the no permit or the deny option on a
particular destination prex neither creates a BFD session on a neighbor nor removes the static routes from the unicast database.
• BFD sessions created using any one IP prex list are active at any given point in time. If a new prex list is assigned, then BFD sessions
corresponding to the older (existing) prex list are replaced with the newer ones.
• Each time a prex list is modied, only addition or deletion of new entries in that prex list are processed for BFD session establishment
or tear down.
Changing Static Route Session Parameters
BFD sessions are congured with default intervals and a default role.
The parameters you can congure are: Desired TX Interval, Required Min RX Interval, Detection Multiplier, and system role. These
parameters are congured for all static routes. If you change a parameter, the change aects all sessions for static routes.
To change parameters for static route sessions, use the following command .
• Change parameters for all static route sessions.
CONFIGURATION mode
ip route bfd [prefix-list prefix-list-name] interval milliseconds min_rx milliseconds
multiplier value role [active | passive]
To view session parameters, use the show bfd neighbors detail command.
Disabling BFD for Static Routes
If you disable BFD, all static route BFD sessions are torn down.
A nal Admin Down packet is sent to all neighbors on the remote systems, and those neighbors change to the Down state.
To disable BFD for static routes, use the following command.
• Disable BFD for static routes.
CONFIGURATION mode
no ip route bfd [prefix-list prefix-list-name] [interval interval min_rx min_rx multiplier
value role {active | passive}]
Congure BFD for IPv6 Static Routes
BFD oers systems a link state detection mechanism for static routes. With BFD, systems are notied to remove static routes from the
routing table as soon as the link state change occurs, rather than waiting until packets fail to reach their next hop.
Conguring BFD for IPv6 static routes is a three-step process:
1 Enable BFD globally.
2 Congure static routes on both routers on the system (either local or remote).
3 Congure an IPv6 route to connect BFD on the static routes using the ipv6 route bfd command.
Related Conguration Tasks
• Changing IPv6 Static Route Session Parameters
• Disabling BFD for Static Routes
Bidirectional Forwarding Detection (BFD)
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