Configuring Static BFD for SR-MPLS TE LSP

Procedure

1. Enable 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. Configure BFD parameters on the ingress.
   1. Run system-view

      The system view is displayed.

   2. Run bfd sessname-value bind mpls-te interface tunnel-name te-lsp [ backup ] [ one-arm-echo ]

      BFD is configured to monitor the primary or backup LSP that is bound to an SR-MPLS TE tunnel.

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

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

   3. Run discriminator local discr-value

      A local discriminator of a BFD session is set.

   4. Run discriminator remote discr-value

      A remote discriminator of a BFD session is set.

      This command does not need to be run if a one-arm BFD session is established.

   5. (Optional) Run min-tx-interval tx-interval

      The minimum interval at which the local device sends BFD packets is changed.

      This command cannot be run for a one-arm BFD session.

      Actual 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 }

      Actual 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 }

      Local BFD detection period = Actual local interval at which BFD packets are received x Remotely configured BFD detection multiplier

      For example: If on the local device, the intervals at which BFD packets are sent and received are 200 ms and 300 ms, respectively, and the detection multiplier is 4; on the remote device, the intervals at which BFD packets are sent and received are 100 ms and 600 ms, respectively, and the detection multiplier is 5, then:

      • On the local device, the actual interval for sending BFD packets is 600 ms calculated using the formula MAX {200 ms, 600 ms}, the actual interval for receiving BFD packets is 300 ms calculated using the formula MAX {100 ms, 300 ms}, and the actual detection period is 1500 ms (300 ms × 5).

      • On the remote device, the actual interval between sending BFD packets is 300 ms calculated using the formula MAX {100 ms, 300 ms}, the actual interval between receiving BFD packets is 600 ms calculated using the formula MAX {200 ms, 600 ms}, and the actual detection period is 2400 ms (600 ms × 4).

   6. (Optional) Run min-rx-interval rx-interval

      The minimum interval at which BFD packets are received locally is set.

      If a one-arm BFD session is to be established, run the min-echo-rx-interval command to set the minimum interval at which BFD packets are received locally.

   7. (Optional) Run detect-multiplier multiplier

      A local BFD detection multiplier is set.

   8. (Optional) Run bit-error-detection

      Bit-error-triggered SR-MPLS TE LSP switching is enabled.

      SR-MPLS TE LSP establishment does not require protocols. Therefore, an SR-MPLS TE LSP can be established as long as a label stack is delivered. If an SR-MPLS TE LSP encounters bit errors, upper-layer services may be affected. With the bit-error-detection command being executed, if BFD detects bit errors on the primary LSP bound to the SR-MPLS TE tunnel, it instructs the SR-MPLS TE tunnel to switch traffic to the backup LSP, minimizing the impact on services.

   9. Run commit

      The configuration is committed.

3. Configure BFD parameters on the egress.
   1. Run system-view

      The system view is displayed.

   2. Run bfd sessname-value bind mpls-te interface tunnel-name te-lsp [ backup ] [ one-arm-echo ]

      BFD is configured to monitor the primary or backup LSP that is bound to an SR-MPLS TE tunnel.

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

   3. Run discriminator local discr-value

      A local discriminator of a BFD session is set.

   4. Run discriminator remote discr-value

      A remote discriminator of a BFD session is set.

      This command does not need to be run if a one-arm BFD session is established.

   5. (Optional) Run min-tx-interval tx-interval

      The minimum interval at which the local device sends BFD packets is changed.

      This command cannot be run for a one-arm BFD session.

      Actual 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 }

      Actual 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 }

      Local BFD detection period = Actual local interval at which BFD packets are received x Remotely configured BFD detection multiplier

      For example: If on the local device, the intervals at which BFD packets are sent and received are 200 ms and 300 ms, respectively, and the detection multiplier is 4; on the remote device, the intervals at which BFD packets are sent and received are 100 ms and 600 ms, respectively, and the detection multiplier is 5, then:

      • On the local device, the actual interval for sending BFD packets is 600 ms calculated using the formula MAX {200 ms, 600 ms}, the actual interval for receiving BFD packets is 300 ms calculated using the formula MAX {100 ms, 300 ms}, and the actual detection period is 1500 ms (300 ms × 5).

      • On the remote device, the actual interval between sending BFD packets is 300 ms calculated using the formula MAX {100 ms, 300 ms}, the actual interval between receiving BFD packets is 600 ms calculated using the formula MAX {200 ms, 600 ms}, and the actual detection period is 2400 ms (600 ms × 4).

   6. (Optional) Run min-rx-interval rx-interval

      The minimum interval at which BFD packets are received locally is set.

      If a one-arm BFD session is to be established, run the min-echo-rx-interval command to set the minimum interval at which BFD packets are received locally.

   7. (Optional) Run detect-multiplier multiplier

      A BFD detection multiplier is set locally.

   8. (Optional) Run bit-error-detection

      Bit-error-triggered SR-MPLS TE LSP switching is enabled.

      SR-MPLS TE LSP establishment does not require protocols. Therefore, an SR-MPLS TE LSP can be established as long as a label stack is delivered. If an SR-MPLS TE LSP encounters bit errors, upper-layer services may be affected. With the bit-error-detection command being executed, if BFD detects bit errors on the primary LSP bound to the SR-MPLS TE tunnel, it instructs the SR-MPLS TE tunnel to switch traffic to the backup LSP, minimizing the impact on services.

   9. Run commit

      The configuration is committed.