BGP Configuration Guidelines > Configuring the BFD Protocol

The bidirectional forwarding detection (BFD) protocol is a simple hello mechanism that detects failures in a network. BFD works with a wide variety of network environments and topologies. The failure detection timers for BFD have shorter time limits than default failure detection mechanisms, providing faster detection. These timers are also adaptive and can be adjusted to be more or less aggressive.

NOTE: BFD is supported only by single-hop EBGP sessions.

To enable failure detection, include the bfd-liveness-detection statement:

bfd-liveness-detection {

    detection-time {

        threshold milliseconds;

    }

    minimum-interval milliseconds;

    minimum-receive-interval milliseconds;

    transmit-interval {

        threshold milliseconds;

        minimum-interval milliseconds;

    }

    multiplier number;

    version (0 | 1 | automatic);

}

To specify the threshold for the adaptation of the detection time, include the threshold statement:

detection-time {

    threshold milliseconds;

}

To specify the minimum transmit and receive interval for failure detection, include the minimum-interval statement:

minimum-interval milliseconds; 

   
NOTE: Specifying an interval smaller than 300ms can cause undesired BFD flapping.


 

To specify only the minimum receive interval for failure detection, include the minimum-receive-interval statement:

minimum-receive-interval milliseconds; 

To specify the detection time multiplier for failure detection, include the multiplier statement:

multiplier number; 

To specify the threshold for detecting the adaptation of the transmit interval, include the threshold statement:

transmit-interval {

    threshold milliseconds;

}

The threshold value must be greater than the transmit interval.

To specify only the minimum transmit interval for failure detection, include the minimum-interval statement:

    transmit-interval {

        minimum-interval milliseconds;

}

To specify the BFD version used for detection, include the version statement:

version (1 | automatic); 

For a list of hierarchy levels at which you can configure these statements, see the statement summary sections for these statements.