Dell Force10 S4810P Configuration Manual page 207

BGP fast fall-over
By default, a BGP session is governed by the hold time. BGP routers typically carry lar ge 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 fall-over is enabled, 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.
Command Syntax
neighbor {ip-address |
peer-group-name} fall-over
To disable Fast Fall-Over, use the
CONFIGURATION ROUTER BGP mode
Use the
show ip bgp neighbors
on a particular BGP neighbor. Note that since Fast Fall-Over is disabled by default, it will appear only if it
has been enabled.
Command Mode
CONFIG-ROUTER-BGP
[no] neighbor [neighbor | peer-group] fall-over
command as shown in Figure 9-22
Purpose
Enable BGP Fast Fall-Over
command in
to verify that fast fall-over is enabled
Border Gateway Protocol | 207