Reference Guide

Prerequisites
Before configuring BFD for BGP, you must first configure the following settings:
1. Configure BGP on the routers that you want to interconnect, as described in Border Gateway Protocol IPv4
(BGPv4).
2. Enable fast fall-over for BGP neighbors to reduce convergence time (the neighbor fall-over command), as
described in BGP Fast Fall-Over.
Establishing Sessions with BGP Neighbors
Before configuring BFD for BGP, you must first configure BGP on the routers that you want to interconnect.
For more information, refer to Border Gateway Protocol IPv4 (BGPv4).
For example, the following illustration shows a sample BFD configuration on Router 1 and Router 2 that use eBGP in a
transit network to interconnect AS1 and AS2. The eBGP routers exchange information with each other as well as with
iBGP routers to maintain connectivity and accessibility within each autonomous system.
Figure 19. Establishing Sessions with BGP Neighbors
The sample configuration shows alternative ways to establish a BFD session with a BGP neighbor:
• By establishing BFD sessions with all neighbors discovered by BGP (the bfd all-neighbors command).
• By establishing a BFD session with a specified BGP neighbor (the neighbor {ip-address | peer-
group-name} bfd command)
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