Reference Guide

226 | Border Gateway Protocol IPv4 (BGPv4)
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BGP graceful restart is active only when the neighbor becomes established. Otherwise it is disabled.
Graceful-restart applies to all neighbors with established adjacency.
With the graceful restart feature, FTOS enables the receiving/restarting mode by default. In receiver-only
mode, graceful restart saves the advertised routes of peers that support this capability when they restart.
However, the E-Series does not advertise that it saves these forwarding states when it restarts. This option
provides support for remote peers for their graceful restart without supporting the feature itself.
You can implement BGP graceful restart either by neighbor or by BGP peer-group. For more information,
please see the following table or the FTOS Command Line Interface Reference.
Filter on an AS-Path attribute
The BGP attribute, AS_PATH, can be used to manipulate routing policies. The AS_PATH attribute
contains a sequence of AS numbers representing the route’s path. As the route traverses an Autonomous
System, the AS number is prepended to the route. You can manipulate routes based on their AS_PATH to
affect interdomain routing. By identifying certain AS numbers in the AS_PATH, you can permit or deny
routes based on the number in its AS_PATH.
To view all BGP path attributes in the BGP database, use the
show ip bgp paths command in EXEC
Privilege mode .
FTOS#show ip bgp paths
Total 30655 Paths
Address Hash Refcount Metric Path
bgp graceful-restart [restart-time
time-in-seconds]
CONFIG-ROUTER-BGP Set maximum restart time for all peers.
Default is 120 seconds.
bgp graceful-restart [stale-path-time
time-in-seconds]
CONFIG-ROUTER-BGP Set maximum time to retain the restarting
peer’s stale paths. Default is 360 seconds.
bgp graceful-restart [role receiver-only] CONFIG-ROUTER-BGP Local router supports graceful restart as a
receiver only.
Command Syntax Command Mode Purpose
neighbor {ip-address |
peer-group-name} graceful-restart
CONFIG-ROUTER-BGP Add graceful restart to a BGP neighbor or
peer-group.
neighbor {ip-address |
peer-group-name} graceful-restart
[restart-time time-in-seconds]
CONFIG-ROUTER-BGP Set maximum restart time for the neighbor or
peer-group. Default is 120 seconds.
neighbor {ip-address |
peer-group-name} graceful-restart
[role receiver-only]
CONFIG-ROUTER-BGP Local router supports graceful restart for this
neighbor or peer-group as a receiver only.
neighbor {ip-address |
peer-group-name} graceful-restart
[stale-path-time time-in-seconds]
CONFIG-ROUTER-BGP Set maximum time to retain the restarting
neighbor’s or peer-group’s stale paths. Default
is 360 seconds.
Command Syntax Command Mode Usage