Reference Guide

222 | Border Gateway Protocol IPv4 (BGPv4)
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If you configure your system to do so, FTOS can perform the following actions during a hot failover:
• Save all FIB and CAM entries on the stack unit and continue forwarding traffic while the stack standby
unit is coming online.
• Advertise to all BGP neighbors and peer-groups that the forwarding state of all routes has been saved.
This prompts all peers to continue saving the routes they receive and to continue forwarding traffic.
• Bring the stack standby online as the master unit and re-open sessions with all peers operating in “no
shutdown” mode.
• Defer best path selection for a certain amount of time. This helps optimize path selection and results in
fewer updates being sent out.
Enable graceful restart using the
configure router bgp graceful-restart command. The table below shows
the command and its available options:
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.
You can implement BGP graceful restart either by neighbor or by BGP peer-group. For more information,
please refer to the following table or the FTOS Command Line Interface Reference.
Command Syntax Command Mode Usage
bgp graceful-restart
CONFIG-ROUTER-
BGP
Enable graceful restart for the BGP node.
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.