Concept Guide

neighbor 192.168.10.1 update-source Loopback 0
neighbor 192.168.10.1 no shutdown
neighbor 192.168.12.2 remote-as 65123
neighbor 192.168.12.2 allowas-in 9
neighbor 192.168.12.2 update-source Loopback 0
neighbor 192.168.12.2 no shutdown
R2(conf-router_bgp)#R2(conf-router_bgp)#
Enabling Graceful Restart
Use this feature to lessen the negative eects of a BGP restart.
Dell EMC Networking OS advertises support for this feature to BGP neighbors through a capability advertisement. You can enable graceful
restart by router and/or by peer or peer group.
NOTE: By default, BGP graceful restart is disabled.
The default role for BGP is as a receiving or restarting peer. If you enable BGP, when a peer that supports graceful restart resumes
operating, Dell EMC Networking OS performs the following tasks:
• Continues saving routes received from the peer if the peer advertised it had graceful restart capability. Continues forwarding trac to
the peer.
• Flags routes from the peer as Stale and sets a timer to delete them if the peer does not perform a graceful restart.
• Deletes all routes from the peer if forwarding state information is not saved.
• Speeds convergence by advertising a special update packet known as an end-of-RIB marker. This marker indicates the peer has been
updated with all routes in the local RIB.
If you congure your system to do so, Dell EMC 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
trac 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 trac.
• 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 following command.
bgp graceful-restart [restart-time seconds] [stale-path-time seconds] [role receiver-only]
To return to the default, use the no bgp graceful-restart command.
• Enable graceful restart for the BGP node.
CONFIG-ROUTER-BGP mode
bgp graceful-restart
• Set maximum restart time, in seconds, to restart and bring-up all the peers.
CONFIG-ROUTER-BGP mode
bgp graceful-restart [restart-time time-in-seconds]
The default is 120 seconds.
• Set maximum time, in seconds, 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.
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Border Gateway Protocol (BGP)