Reference Guide

typical response is to terminate the peering session for the routing protocol and reconverge by bypassing
the failed neighboring router. A log message is generated whenever BFD detects a failure condition.
1. Enable BFD globally.
CONFIGURATION mode
bfd enable
2. Specify the AS number and enter ROUTER BGP configuration mode.
CONFIGURATION mode
router bgp as-number
3. Add a BGP neighbor or peer group in a remote AS.
CONFIG-ROUTERBGP mode
neighbor {ip-address | peer-group name} remote-as as-number
4. Enable the BGP neighbor.
CONFIG-ROUTERBGP mode
neighbor {ip-address | peer-group-name} no shutdown
5. Configure parameters for a BFD session established with all neighbors discovered by BGP. OR
Establish a BFD session with a specified BGP neighbor or peer group using the default BFD session
parameters.
CONFIG-ROUTERBGP mode
bfd all-neighbors [interval millisecs min_rx millisecs multiplier value role
{active | passive}]
OR
neighbor {ip-address | peer-group-name} bfd
NOTES:
• When you establish a BFD session with a specified BGP neighbor or peer group using the
neighbor bfd command, the default BFD session parameters are used (interval: 100
milliseconds, min_rx: 100 milliseconds, multiplier: 3 packets, and role: active).
• When you explicitly enable or disable a BGP neighbor for a BFD session with the neighbor bfd
or neighbor bfd disable commands, the neighbor does not inherit the BFD enable/disable
values configured with the bfd all-neighbors command or configured for the peer group to
which the neighbor belongs. Also, the neighbor only inherits the global timer values configured
with the bfd all-neighbors command (interval, min_rx, and multiplier).
6. Repeat Steps 1 to 5 on each BGP peer participating in a BFD session.
Disabling BFD for BGP
You can disable BFD for BGP.
To disable a BFD for BGP session with a specified neighbor, use the first command. To remove the
disabled state of a BFD for BGP session with a specified neighbor, use the second command.
The BGP link with the neighbor returns to normal operation and uses the BFD session parameters globally
configured with the bfd all-neighbors command or configured for the peer group to which the
neighbor belongs.
• Disable a BFD for BGP session with a specified neighbor.
Bidirectional Forwarding Detection (BFD)
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