Associating a BFD Session with a Sub-interface

Association between a BFD session and a sub-interface triggers rapid route convergence. Only a single-hop BFD session with a default multicast IP address can be bound to a sub-interface.

Usage Scenario

If high reliability is required and sub-interfaces are configured with a large number of services, only a BFD session needs to be configured on an interface not on each sub-interface. The BFD session can be associated with the sub-interface status to allow the sub-interface's protocol status to be synchronized with the interface's protocol status. This association improves service reliability and saves BFD session resources.

Pre-configuration Tasks

Before associating a BFD session with a sub-interface, complete the following tasks:

Enable BFD globally.
Create a single-hop BFD session, bind it to an interface, and configure the default multicast address for detection.
Set up the BFD session and ensure that the BFD session is Up.

Procedure

Run system-view
The system view is displayed.
Run bfd session-name
The BFD session view is displayed.
Run process-interface-status [sub-if] [ reboot-no-impact ]
The BFD session is associated with the sub-interface.
Run commit
The configuration is committed.

If a BFD session goes Down, the BFD status on the interface bound to the BFD session and its sub-interfaces also becomes Down.