Reference Guide

applied to the peer group members. When you disable a peer group, all the peers within the peer group
that are in the ESTABLISHED state move to the IDLE state.
To view the status of peer groups, use the show ip bgp peer-group command in EXEC Privilege
mode, as shown in the following example.
Dell>show ip bgp peer-group
Peer-group zanzibar, remote AS 65535
BGP version 4
Minimum time between advertisement runs is 5 seconds
For address family: IPv4 Unicast
BGP neighbor is zanzibar, peer-group internal,
Number of peers in this group 26
Peer-group members (* - outbound optimized):
10.68.160.1
10.68.161.1
10.68.162.1
10.68.163.1
10.68.164.1
10.68.165.1
10.68.166.1
10.68.167.1
10.68.168.1
10.68.169.1
10.68.170.1
10.68.171.1
10.68.172.1
10.68.173.1
10.68.174.1
10.68.175.1
10.68.176.1
10.68.177.1
10.68.178.1
10.68.179.1
10.68.180.1
10.68.181.1
10.68.182.1
10.68.183.1
10.68.184.1
10.68.185.1
Dell>
Configuring BGP Fast Fall-Over
By default, the hold time governs a BGP session.
BGP routers typically carry large routing tables, so frequent session resets are not desirable. The BGP fast
fall-over feature reduces the convergence time while maintaining stability. The connection to a BGP peer
is immediately reset if a link to a directly connected external peer fails.
When you enable fall-over, BGP tracks IP reachability to the peer remote address and the peer local
address. Whenever either address becomes unreachable (for example, no active route exists in the
routing table for peer IPv6 destinations/local address), BGP brings down the session with the peer.
The BGP fast fall-over feature is configured on a per-neighbor or peer-group basis and is disabled by
default.
206
Border Gateway Protocol IPv4 (BGPv4)