Administrator Guide

Table Of Contents
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, a BGP session is governed by the hold time.
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.
To enable the BGP fast fall-over feature, use the following command.
To disable fast fall-over, use the [no] neighbor [neighbor | peer-group] fall-over command in
CONFIGURATION ROUTER BGP mode.
Enable BGP Fast fall-Over.
CONFIG-ROUTER-BGP mode
neighbor {ip-address | peer-group-name} fall-over
To verify that you enabled fast fall-over on a particular BGP neighbor, use the show ip bgp neighbors command. Because
fast fall-over is disabled by default, it appears only if it has been enabled (shown in bold).
Dell#sh ip bgp neighbors
BGP neighbor is 100.100.100.100, remote AS 65517, internal link
Border Gateway Protocol IPv4 (BGPv4)
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