Juniper IGP - CONFIGURATION GUIDE V11.1.X, Configuration Manual

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OSPFv3 (respectively). 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.
When you issue the ip ospf bfd-liveness-detection or ipv6 ospf
bfd-liveness-detection command on an OSPF peer, the peer establishes BFD liveness
detection with all BFD-enabled OSPF peers. When the local peer receives an update
from a remote OSPF peer—if BFD is enabled and if the session is not already
present—the local peer attempts to create a BFD session to the remote peer.
Each adjacent pair of peers negotiates an acceptable transmit interval for BFD packets.
The negotiated value can be different on each peer. Each peer then calculates a BFD
liveness detection interval. When a peer does not receive a BFD packet within the
detection interval, it declares the BFD session to be down and purges all routes
learned from the remote peer.
NOTE: Before the router can use the ip ospf bfd-liveness-detection or ipv6 ospf
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
JUNOSe IP Services Configuration Guide .
ip ospf bfd-liveness-detection
ipv6 ospf bfd-liveness-detection
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Use to enable BFD (bidirectional forwarding detection) and define BFD values
to more quickly detect OSPFv2 or OSPFv3 data path failures.
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The peers in an OSPF adjacency use the configured values to negotiate the actual
transmit intervals for BFD packets.
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You can use the minimum-transmit-interval keyword to specify the interval
at which the local peer proposes to transmit BFD control packets to the
remote peer. The default value is 300 milliseconds.
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You can use the minimum-receive-interval keyword to specify the minimum
interval at which the local peer must receive BFD control packets from the
remote peer. The default value is 300 milliseconds.
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You can use the minimum-interval keyword to specify the same value for
both of those intervals. Configuring a minimum interval has the same effect
as configuring the minimum receive interval and the minimum transmit
interval to the same value. The default value is 300 milliseconds.
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You can use the multiplier keyword to specify the detection multiplier value.
The calculated BFD liveness detection interval can be different on each peer.
The multiplier value is roughly equivalent to the number of packets that can be
missed before the BFD session is declared to be down. The default value is 3.
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For details on liveness detection negotiation, see JUNOSe IP Services Configuration
Guide .
Configuring the BFD Protocol for OSPF
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Chapter 5: Configuring OSPF