Configuring SBFD for SR-MPLS TE LSP

This section describes how to configure SBFD to detect SR-MPLS TE LSP faults.

Usage Scenario

If SBFD for SR-MPLS TE LSP detects a fault on the primary LSP, traffic is rapidly switched to the backup LSP, which minimizes the impact on traffic.

Pre-configuration Tasks

Before configuring SBFD for SR-MPLS TE LSP, complete the following task:

Configure an SR-MPLS TE tunnel.
Set each LSR ID using the mpls lsr-id lsr-id command. Ensure that the route to the local lsr-id is reachable.

Procedure

Configure an SBFD initiator.
1. Run system-view
  The system view is displayed.
2. Run bfd
  BFD is enabled globally.
  
  You can set BFD parameters only after running the bfd command to enable global BFD.
3. Run quit
  Return to the system view.
4. Run sbfd
  SBFD is enabled globally.
5. Run quit
  Return to the system view.
6. Run interface tunnel tunnel-number
  The SR-MPLS TE tunnel interface view is displayed.
7. Run mpls te bfd enable seamless
  SBFD for SR-MPLS TE LSP is enabled.
  
  After the configuration is complete, the SBFD initiator automatically establishes an SBFD session destined for the destination IP address of an SR-MPLS TE tunnel.
8. (Optional) Run mpls te reverse-lsp binding-sid label label-value
  A label for the SR-MPLS TE tunnel used for BFD return packets is configured. This label must be the binding SID of the tunnel.
  
  Before running this command, ensure that the mpls te binding-sid label label-value command has been run on the ingress of the reverse SR-MPLS TE tunnel.
  
  In SBFD for SR-MPLS TE LSP scenarios, SBFD packets from the initiator to the reflector are forwarded along an SR-MPLS TE LSP, whereas the return packets from the reflector to the initiator are forwarded along a multi-hop IP path. To allow the return packets to be forwarded also along an LSP, run the mpls te reverse-lsp binding-sid command.
  
  Both the forward and reverse SR-MPLS TE tunnels may have a primary LSP and a backup LSP. After the mpls te reverse-lsp binding-sid command is run, the SBFD packet sent by the initiator carries the primary/backup LSP flag. If the SBFD packet sent by the initiator is forwarded through the primary LSP of the forward tunnel, the SBFD return packet sent by the reflector is forwarded through the primary LSP of the reverse tunnel. If the SBFD packet sent by the initiator is forwarded through the backup LSP of the forward tunnel, the SBFD return packet sent by the reflector is forwarded through the backup LSP of the reverse tunnel.
9. Run commit
  The configuration is committed.
Configure the SBFD reflector.
1. Run system-view
  The system view is displayed.
2. Run bfd
  BFD is enabled globally.
  
  You can set BFD parameters only after running the bfd command to enable global BFD.
3. Run quit
  Return to the system view.
4. Run sbfd
  SBFD is enabled globally.
5. Run reflector discriminator { unsigned-integer-value | ip-address-value }
  The discriminator of an SBFD reflector is configured.
6. Run commit
  The configuration is committed.

Verifying the Configuration

After you configure SBFD for SR-MPLS TE LSP, run the display bfd session { all | discriminator discr-value } [ verbose ] command to check information about the SBFD session that monitors an SR-MPLS TE tunnel.