Configuring The Bfd Protocol For Pim - Juniper JUNOSE 11.0.X MULTICAST ROUTING Configuration Manual

JUNOSe 11.0.x Multicast Routing Configuration Guide

Configuring the BFD Protocol for PIM

The ip pim bfd-liveness-detection command configures the Bidirectional Forwarding
Detection (BFD) protocol for PIM. The BFD protocol uses control packets and shorter
detection time limits to more rapidly detect failures in a network. Also, because they
are adjustable, you can modify the BFD timers for more or less aggressive failure
detection.
PIM routers send periodic hello messages from each PIM-enabled interface. You can
configure this interval using the ip pim query-interval command. By default, the
PIM router sends a hello message every 30 seconds (with an interval range of 0–210
seconds). If it receives no response from a neighbor within 3.5 times the interval
value (a minimum of 3.5 seconds), the PIM router drops the neighbor.
In contrast, when a BFD session exists between neighbors, a PIM neighbor that goes
down is detected quickly (in milliseconds rather than in seconds).
When you issue the ip pim bfd-liveness-detection command on a PIM router, the
router establishes BFD liveness detection with all BFD-enabled PIM neighbors. When
the local router receives an update from a remote PIM neighbor if BFD is enabled
and if the session is not already present the local router attempts to create a BFD
session to the remote neighbor.
Each adjacent pair of neighbors negotiates an acceptable transmit interval for BFD
packets. The negotiated value can be different on each neighbor. Each neighbor then
calculates a BFD liveness detection interval. When a neighbor does not receive a BFD
packet within the detection interval, it declares the BFD session to be down.
NOTE: Before the router can use the ip pim bfd-liveness-detection command, you
must specify a BFD license key. To view an already configured license, use the show
license bfd command.
For general information about configuring and monitoring the BFD protocol, see
Configuring BFD in the JUNOSe IP Services Configuration Guide.
ip pim bfd-liveness-detection
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Configuring the BFD Protocol for PIM

Use the no version to disable SSM.
See ip pim ssm.
Use to enable BFD (bidirectional forwarding detection) and define BFD values
to more quickly detect PIM data path failures.
The neighbors in a PIM network use the configured values to negotiate the actual
transmit intervals for BFD packets.
You can use the minimum-transmit-interval keyword to specify the interval
at which the local router proposes to transmit BFD control packets to its
neighbors. The default value is 300 milliseconds.