Enabling Neighbor Graceful Restart - Dell Z9000 Configuration Manual

If you configure your system to do so, Dell Networking OS can perform the following actions during a
hot failover:
• Save all forwarding information base (FIB) and content addressable memory (CAM) entries on the line
card and continue forwarding traffic while the secondary route processor module (RPM) 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 secondary RPM online as the primary 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.
To enable graceful restart, use the configure router bgp graceful-restart command.
• Enable graceful restart for the BGP node.
CONFIG-ROUTER-BGP mode
bgp graceful-restart
• Set maximum restart time for all peers.
CONFIG-ROUTER-BGP mode
bgp graceful-restart [restart-time time-in-seconds]
The default is 120 seconds.
• Set maximum time to retain the restarting peer's stale paths.
CONFIG-ROUTER-BGP mode
bgp graceful-restart [stale-path-time time-in-seconds]
The default is 360 seconds.
• Local router supports graceful restart as a receiver only.
CONFIG-ROUTER-BGP mode
bgp graceful-restart [role receiver-only]

Enabling Neighbor Graceful Restart

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, Dell Networking OS 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. 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,
refer to the Dell Networking OS Command Line Interface Reference Guide.
• Add graceful restart to a BGP neighbor or peer-group.
CONFIG-ROUTER-BGP mode
neighbor {ip-address | peer-group-name} graceful-restart
Border Gateway Protocol IPv4 (BGPv4)
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