Configure BFD for BGP
In a BGP core network, bidirectional forwarding detection (BFD) provides rapid detection of
communication failures in BGP fast-forwarding paths between internal BGP (iBGP) and external BGP
(eBGP) peers for faster network reconvergence.
BFD for BGP is supported on 1GE, 10GE, 40GE, port-channel, and VLAN interfaces. BFD for BGP does not
support IPv6 and the BGP multihop feature.

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 Configuring BGP Fast Fail-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.
Bidirectional Forwarding Detection (BFD) 159