(Optional) Configuring BFD on a Specified Interface

Procedure

1. Run system-view

   The system view is displayed.

2. (Optional) To configure BFD session check for an IS-IS process, perform the following steps:
   1. Run isis [ process-id ]

      The IS-IS view is displayed.

   2. Run bfd session-up check .

      BFD session check is configured for the IS-IS process.

   

   When the Layer 2 network is running normally, IS-IS neighbor relationships can be established and routes can be delivered. However, if the Layer 3 network is unreachable, upper-layer traffic loss occurs. To resolve this problem, configure BFD session check for an IS-IS process by running the bfd session-up check command. This ensures that an IS-IS neighbor relationship is established only when the BFD session is up on corresponding interfaces. After this function is configured, it applies only to the neighbor relationships to be established (it does not apply to existing neighbor relationships).

3. Run interface interface-type interface-number

   The interface view is displayed.

   

   An interface in this case may be a physical interface or a GRE tunnel interface. If BFD is enabled on a GRE tunnel interface, millisecond-level fault detection can be implemented for the GRE tunnel.

4. Run isis bfd enable

   BFD is enabled on the interface to establish BFD sessions.

   BFD must be enabled globally before you perform this step. If BFD is enabled globally, this step is performed, and the status of neighbors is up (or the DIS is up in the case of a broadcast network), default BFD parameters are used by this interface to establish BFD sessions.

5. (Optional) Run isis bfd { min-rx-interval receive-interval | min-tx-interval transmit-interval | detect-multiplier multiplier-value | frr-binding | tos-exp tosexp-value } ^*

   The parameters are set for the specified interface to dynamically establish BFD sessions.

   If tos-exp tosexp-value is specified, a priority is configured for all IS-IS BFD packets on the current interface.

   

   BFD configured on an interface takes precedence over BFD configured for a process. If both of them are configured, the parameters on the interface take effect.

6. (Optional) Run isis bfd incr-cost { cost-value | max-reachable }

   The specified interface is enabled to adjust its cost based on the status of an associated BFD session.

   Regarding the configuration of adjusting the interface cost based on the status of an associated BFD session, the configuration in the interface view takes precedence over that in the IS-IS view.

7. Run commit

   The configuration is committed.