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Configuring BFD for VCCV for Layer 2 Circuits

Bidirectional Forwarding Detection (BFD) support for virtual circuit connection verification (VCCV) allows you to configure a control channel for a pseudowire, in addition to the corresponding operations and management functions to be used over that control channel. BFD provides a low resource mechanism for the continuous monitoring of the pseudowire data path and for detecting data plane failures. This feature provides support for asynchronous mode BFD for VCCV as described in RFC 5885, Bidirectional Forwarding Detection (BFD) for the Pseudowire Virtual Circuit Connectivity Verification (VCCV). You can also use a ping to detect pseudowire failures. However, the processing resources required for a ping are greater than what is needed for BFD. In addition, BFD is capable of detecting data plane failure faster than VCCV ping. BFD for pseudowires is supported for Layer 2 circuits (LDP-based).

Before you begin:

  • Configure the device interfaces.

To configure BFD for VCCV:

  1. Specify the threshold for the adaptation of the BFD session detection time.

    For example, to set a detection time threshold of 40 milliseconds for OAM BFD liveness detection:

  2. Configure the virtual circuit ID for the Layer 2 circuit protocol.

    For example, to set the virtual circuit ID as 1 for OAM BFD liveness detection:

  3. Configure the minimum interval after which the local routing device transmits hello packets and then expects to receive a reply from a neighbor with which it has established a BFD session for the Layer 2 circuit.

    For example, to set a minimum interval of 300 milliseconds for OAM BFD liveness detection:

  4. Configure the minimum interval after which the local routing device must receive a reply from a neighbor with which it has established a BFD session for the Layer 2 circuit protocol.

    For example, to set a minimum receive interval of 10 milliseconds for OAM BFD liveness detection:

  5. Configure the number of hello packets not received by a neighbor that causes the originating interface to be declared down for the Layer 2 circuit protocol.

    For example, to set the multiplier as 3 for OAM BFD liveness detection:

  6. Configure to disable adaptation.
  7. Configure the minimum interval at which the local routing device transmits hello packets to a neighbor with which it has established a BFD session.

    For example, to set a minimum transmit interval of 5 milliseconds for OAM BFD liveness detection:

  8. Specify the threshold for the adaptation of the BFD session transmit interval.

    For example, to set a transmit interval threshold of 30 milliseconds for OAM BFD liveness detection: