Reference Guide

Bidirectional Forwarding Detection | 175
Disabling and re-enabling BFD
BFD is enabled on all interfaces by default, though sessions are not created unless explicitly configured. If
BFD is disabled, all of the sessions on that interface are placed in an Administratively Down state
(Message 2), and the remote systems are notified of the session state change (Message 3).
To disable BFD on an interface:
To re-enable BFD on an interface:
Configuring BFD for Static Routes
BFD gives systems a link state detection mechanism for static routes. With BFD, systems are notified to
remove static routes from the routing table as soon as the link state change occurs, rather than having to
wait until packets fail to reach their next hop.
Configuring BFD for static routes is a three-step process:
1. Enable BFD globally. Refer to Enabling BFD globally.
2. On the local system, establish a session with the next hop of a static route. Refer to Establishing
sessions for static routes.
3. On the remote system, establish a session with the physical port that is the origin of the static route.
Refer to Establishing a session on physical ports.
Related configuration tasks
• Changing static route session parameters.
• Disabling BFD for static routes.
Step Task Command Syntax Command Mode
1 Disable BFD on an interface. no bfd enable INTERFACE
Message 2 Disabling BFD on a Local Interface
R1(conf-if-gi-4/24)#01:00:52: %RPM0-P:RP2 %BFDMGR-1-BFD_STATE_CHANGE: Changed session
state to Ad Dn for neighbor 2.2.2.2 on interface Gi 4/24 (diag: 0)
Message 3 Remote System State Change due to Local State Admin Down
R2>01:32:53: %RPM0-P:RP2 %BFDMGR-1-BFD_STATE_CHANGE: Changed session state to Down for
neighbor 2.2.2.1 on interface Gi 2/1 (diag: 7)
Step Task Command Syntax Command Mode
1 Enable BFD on an interface. bfd enable INTERFACE