DELL S50V User Manual

Border Gateway Protocol IPv4 (BGPv4) | 241

Enable graceful restart

Use this feature to lessen the negative effects of a BGP restart. FTOS 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.

The default role for BGP on is as a receiving or restarting peer. If you enable BGP, when a peer that 
supports graceful restart resumes operating, FTOS performs the following tasks:

•

Continues saving routes received from the peer if the peer advertised it had graceful restart capability. 
Continues forwarding traffic 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 configure your system to do so, FTOS can perform the following actions during a hot failover:

•

Save all FIB and CAM entries on the line card and continue forwarding traffic while the secondary 
RPM is coming online.

Note: By default, BGP graceful restart is disabled.

R2(conf-router_bgp)#show conf

!

router bgp 65123

 bgp router-id 192.168.10.2

 network 10.10.21.0/24

 network 10.10.32.0/24

 network 100.10.92.0/24

 network 192.168.10.0/24

 bgp four-octet-as-support

 neighbor 10.10.21.1 remote-as 65123

 neighbor 10.10.21.1 filter-list Laura in

 neighbor 10.10.21.1 no shutdown

 neighbor 10.10.32.3 remote-as 65123

 neighbor 10.10.32.3 no shutdown

 neighbor 100.10.92.9 remote-as 65192

 neighbor 100.10.92.9 local-as 6500

 neighbor 100.10.92.9 no shutdown

 neighbor 192.168.10.1 remote-as 65123

 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)#

Number of Times ASN 65123
Can Appear in AS PATH