Bidirectional Forwarding Detection (BFD)

NOTE:

BFD is intended for use only on v3 modules.

Bidirectional Forwarding Detection (BFD) is a low-overhead, short-duration method for detection of failures in the path between adjacent forwarding engines, including the interfaces, data link(s), and, to the extent possible, the forwarding engines themselves. It also provides a single mechanism that can be used for liveness detection between a pair of devices over any media, at any protocol layer, with a wide range of Detection Times and overhead, to avoid proliferation of different methods.

Asynchronous mode:In Asynchronous mode, an operating device periodically sends BFD control packets. If the device does not receive BFD control packet from the peer within the specified interval, it tears down the BFD session.

Echo mode: In Echo mode, an operating device periodically sends BFD echo packets. The peer device returns the received BFD echo packets back without processing them. If the sending device does not receive BFD echo packet from the peer within the specified interval, the session is considered down.