Configuring Dynamic BFD for SR-MPLS TE LSP

Procedure

1. Enabling BFD Globally
   1. Run system-view

      The system view is displayed.

   2. Run bfd

      BFD is enabled globally, and the BFD view is displayed.

      You can set BFD parameters only after running the bfd command to enable BFD globally.

   3. Run commit

      The configuration is committed.

2. Enabling the Ingress to Dynamically Create a BFD Session to Monitor SR-MPLS TE LSPs

   Perform either of the following operations to enable the ingress to dynamically create a BFD Session to monitor SR-MPLS TE LSPs:

   • Globally enable the capability if BFD sessions need to be automatically created for most SR-MPLS TE tunnels on the ingress.

   • Enable the capability on a specific tunnel interface if a BFD session needs to be automatically created for a specific or some SR-MPLS TE tunnels on the ingress.

   Please select the appropriate configuration according to your actual needs.

   • Globally enable the capability.

     1. Run system-view

        The system view is displayed.

     2. Run mpls

        The MPLS view is displayed.

     3. Run mpls te bfd enable [ one-arm-echo ]

        The ingress is configured to automatically create a BFD session for each SR-MPLS TE tunnel.

        After this command is run in the MPLS view, BFD for SR-MPLS TE LSP is enabled on all tunnel interfaces, except the tunnel interfaces on which BFD for SR-MPLS TE LSP is blocked.

        If one-arm-echo is configured, a one-arm BFD echo session is established to monitor an SR-MPLS TE LSP.

        If the egress does not support BFD for SR-MPLS TE, BFD sessions cannot be created. To address this issue, configure one-arm BFD.

     4. (Optional) If some SR-MPLS TE tunnels do not need to be monitored using BFD for SR-MPLS TE LSP, block BFD for SR-MPLS TE LSP on each tunnel interface:
        1. Run quit

           Return to the system view.

        2. Run interface tunnel interface-number

           The SR-MPLS TE tunnel interface view is displayed.

        3. Run mpls te bfd block

           The tunnel interface is disabled from automatically creating a BFD session to monitor an SR-MPLS TE tunnel.

     5. Run commit

        The configuration is committed.

   • Enable the capability on a tunnel interface.
     • Run system-view

       The system view is displayed.

     • Run interface tunnel interface-number

       The view of the SR-MPLS TE tunnel interface is displayed.

     • Run mpls te bfd enable [ one-arm-echo ]

       The ingress is configured to automatically create a BFD session for the tunnel.

       This command run in the tunnel interface view takes effect only on the tunnel interface.

       If one-arm-echo is configured, a one-arm BFD echo session is established to monitor an SR-MPLS TE LSP. A Huawei device at the ingress cannot use BFD for SR-MPLS TE LSP to communicate with a non-Huawei device at the egress. In this situation, no BFD session can be established. To address this issue, configure one-arm BFD.

     • Run commit

       The configuration is committed.

3. Enabling the Egress to Passively Create a BFD Session
   1. Run system-view

      The system view is displayed.

   2. Run bfd

      The BFD view is displayed.

   3. Run mpls-passive

      The egress is enabled to create a BFD session passively.

      The egress has to receive an LSP ping request carrying a BFD TLV before creating a BFD session.

   4. Run commit

      The configuration is committed.

4. (Optional) Adjusting BFD Parameters on the Ingress

   Adjust BFD parameters on the ingress in either of the following modes:

   • Adjust BFD parameters globally. This method is used when BFD parameters for most SR-MPLS TE tunnels need to be adjusted on the ingress.

   • Adjust BFD parameters on a specific tunnel interface. If an SR-MPLS TE tunnel interface needs BFD parameters different from the globally configured ones, adjust BFD parameters on the specific tunnel interface.

   

   • Effective local interval at which BFD packets are sent = MAX { Locally configured interval at which BFD packets are sent, Remotely configured interval at which BFD packets are received }
   • Effective local interval at which BFD packets are received = MAX { Remotely configured interval at which BFD packets are sent, Locally configured interval at which BFD packets are received }
   • Effective local BFD detection period = Effective local interval at which BFD packets are received x Remotely configured BFD detection multiplier

   On the egress that passively creates a BFD session, the BFD parameters cannot be adjusted, because the default values are the smallest values that can be set on the ingress. Therefore, if BFD for TE is used, the effective BFD detection period on both ends of an SR-MPLS TE tunnel is as follows:

   • Effective detection period on the ingress = Configured interval at which BFD packets are received on the ingress x 3

   • Effective detection period on the egress = Configured interval at which BFD packets are sent on the ingress x Configured detection multiplier on the ingress

   Please select the appropriate configuration according to your actual needs.

   • Adjust BFD parameters globally.
     • Run system-view

       The system view is displayed.

     • Run mpls

       The MPLS view is displayed.

     • Run mpls te bfd { min-tx-interval tx-interval | min-rx-interval rx-interval | detect-multiplier multiplier }*

       The BFD parameters are set.

     • Run commit

       The configuration is committed.

   • Adjust BFD parameters on a specific tunnel interface.
     • Run system-view

       The system view is displayed.

     • Run interface tunnel interface-number

       The tunnel interface view is displayed.

     • Run mpls te bfd { min-tx-interval tx-interval | min-rx-interval rx-interval | detect-multiplier multiplier }*

       The BFD parameters are set.

     • Run commit

       The configuration is committed.