Configuring the BFD Protocol for PIM

The bidirectional forwarding detection (BFD) protocol uses control packets and shorter detection time limits to detect failures more rapidly in a network. Working with a wide variety of network environments and topologies, BFD failure detection timers provide faster detection by using shorter time limits than the PIM hello hold time. These timers are also adaptive and you can adjust them to be more or less aggressive.

You must specify the minimum transmit and minimum receive intervals to enable BFD on PIM.

To enable failure detection:

1. Configure the interface globally or in the routing instance. This example shows the global configuration.
   [edit]user@host# edit protocols pim interface fe-1/0/0.0 bfd-liveness-detection
2. Configure the minimum transmit interval. This is the minimum interval at which the routing device transmits hello packets to a neighbor with which it has established a BFD session. Specifying an interval smaller than 300 ms can cause undesired BFD flapping.
   [edit protocols pim interface fe-1/0/0.0 bfd-liveness-detection]user@host# set transmit–interval 350
3. Configure the minimum interval at which the routing device expects to receive a reply from a neighbor with which it has established a BFD session. Specifying an interval smaller than 300 ms can cause undesired BFD flapping.
   [edit protocols pim interface fe-1/0/0.0 bfd-liveness-detection]user@host# set minimum-receive-interval 350
4. (Optional) Configure other BFD settings.

   As an alternative to setting the receive and transmit intervals separately, you can configure one interval for both.

   [edit protocols pim interface fe-1/0/0.0 bfd-liveness-detection]user@host# set minimum-interval 350

   Configure the detection-time threshold. When the BFD protocol session detection time adapts to a value equal to or greater than the threshold, a single trap and a single system log message are sent.

   [edit protocols pim interface fe-1/0/0.0 bfd-liveness-detection]user@host# set detection-time threshold 800

   Configure the number of hello packets not received by a neighbor that causes the originating interface to be declared down.

   [edit protocols pim interface fe-1/0/0.0 bfd-liveness-detection]user@host# set multiplier 50

   Configure the BFD version.

   [edit protocols pim interface fe-1/0/0.0 bfd-liveness-detection]user@host# set version 1

   Specify that BFD sessions should not adapt to changing network conditions. We recommend that you not disable BFD adaptation unless it is preferable not to have BFD adaptation enabled in your network.

   [edit protocols pim interface fe-1/0/0.0 bfd-liveness-detection]user@host# set no-adaptation
5. Verify the configuration by checking the output of the show bfd session command.

Related Topics

• show bfd session in the Routing Protocols and Policies Command Reference