Service Manual

Use BFD in a BGP Peer Group
You can establish a BFD session for the members of a peer group (the neighbor peer-group-name bfd command in
ROUTER BGP conguration mode).
Members of the peer group may have BFD:
• Explicitly enabled (the neighbor ip-address bfd command)
• Explicitly disabled (the neighbor ip-address bfd disable command)
• Inherited (neither explicitly enabled or disabled) according to the current BFD conguration of the peer group. For information
about BGP peer groups, refer to Congure Peer Groups.
If you explicitly enable (or disable) a BGP neighbor for BFD that belongs to a peer group:
• The neighbor does not inherit the BFD enable/disable values congured with the bfd all-neighbors command or
congured for the peer group to which the neighbor belongs.
• The neighbor inherits only the global timer values that are congured with the bfd all-neighbors command (interval,
min_rx, and multiplier).
If you explicitly enable (or disable) a peer group for BFD that has no BFD parameters congured (for example, advertisement
interval) using the neighbor peer-group-name bfd command, the peer group inherits any BFD settings congured with the
bfd all-neighbors command.
Displaying BFD for BGP Information
You can display related information for BFD for BGP.
To display information about BFD for BGP sessions on a router, use the following commands and refer to the following examples.
• Verify a BFD for BGP conguration.
EXEC Privilege mode
show running-config bgp
• Verify that a BFD for BGP session has been successfully established with a BGP neighbor. A line-by-line listing of established
BFD adjacencies is displayed.
EXEC Privilege mode
show bfd neighbors [interface] [detail]
• Check to see if BFD is enabled for BGP connections.
EXEC Privilege mode
show ip bgp summary
• Displays routing information exchanged with BGP neighbors, including BFD for BGP sessions.
EXEC Privilege mode
show ip bgp neighbors [ip-address]
Examples of the BFD show Commands
The following example shows verifying a BGP conguration.
R2# show running-config bgp
!
router bgp 2
neighbor 1.1.1.2 remote-as 1
neighbor 1.1.1.2 no shutdown
neighbor 2.2.2.2 remote-as 1
neighbor 2.2.2.2 no shutdown
neighbor 3.3.3.2 remote-as 1
neighbor 3.3.3.2 no shutdown
bfd all-neighbors
Bidirectional Forwarding Detection (BFD)
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