Re-enabling BGP4+ graceful restart

If the BGP4+ graceful restart (GR) feature is disabled on a routing device, it can be re-enabled, providing it with the capability to inform its neighbors and peers when it is performing a restart.
  1. Enter the configure terminal command to access global configuration mode. 
    device# configure terminal
  2. Enter the router bgp command to enable BGP routing. 
    device(config)# router bgp
  3. Enter the local-as command to configure the autonomous system number (ASN) in which your device resides. 
    device(config-bgp-router)# local-as 1000
  4. Enter the neighbor ipv6-address remote-as command to specify the autonomous system ASN in which the remote neighbor resides. 
    device(config-bgp-router)# neighbor 1000::1 remote-as 2
  5. Enter the address-family command and specify the ipv6 and unicast keywords to enter IPv6 address family configuration mode. 
    device(config-bgp-router)# address-family ipv6 unicast
  6. Enter the neighbor ipv6-address activate command to add a neighbor. 
    device(config-bgp-ipv6u)# neighbor 1000::1 activate
  7. Enter the graceful-restart command to enable the graceful restart feature. 
    device(config-bgp-ipv6u)# graceful-restart
  8. Do any of the following:
    • Enter the graceful-restart command using the purge-time keyword to overwrite the default purge-time value. 
      device(config-bgp-ipv6u)# graceful-restart purge-time 300
    • Enter the graceful-restart command using the restart-time keyword to overwrite the default restart-time advertised to graceful restart-capable neighbors. 
      device(config-bgp-ipv6u)# graceful-restart restart-time 180
    • Enter the graceful-restart command using the stale-routes-time keyword to overwrite the default amount of time that a helper device will wait for an EOR message from a peer. 
      device(config-bgp-ipv6u)# graceful-restart stale-routes-time 100

The following example re-enables the graceful restart feature. 

device# configure terminal
device(config)# router bgp
device(config-bgp-router)# local-as 1
device(config-bgp-router)# neighbor 1000::1 remote-as 2
device(config-bgp-router)# address-family ipv6 unicast
device(config-bgp-ipv6u)# neighbor 1000::1 activate
device(config-bgp-ipv6u)# graceful-restart

The following example re-enables the graceful restart feature and sets the purge time to 300 seconds, overwriting the default value. 

device# configure terminal
device(config)# router bgp
device(config-bgp-router)# local-as 1
device(config-bgp-router)# neighbor 1000::1 remote-as 2
device(config-bgp-router)# address-family ipv6 unicast
device(config-bgp-ipv6u)# neighbor 1000::1 activate
device(config-bgp-ipv6u)# graceful-restart purge-time 300

The following example re-enables the graceful restart feature and sets the restart time to 180 seconds, overwriting the default value. 

device# configure terminal
device(config)# router bgp
device(config-bgp-router)# local-as 1
device(config-bgp-router)# neighbor 1000::1 remote-as 2
device(config-bgp-router)# address-family ipv6 unicast
device(config-bgp-ipv6u)# neighbor 1000::1 activate
device(config-bgp-ipv6u)# graceful-restart restart-time 180

The following example re-enables the graceful restart feature and sets the stale-routes time to 100 seconds, overwriting the default value. 

device# configure terminal
device(config)# router bgp
device(config-bgp-router)# local-as 1
device(config-bgp-router)# neighbor 1000::1 remote-as 2
device(config-bgp-router)# address-family ipv6 unicast
device(config-bgp-ipv6u)# neighbor 1000::1 activate
device(config-bgp-ipv6u)# graceful-restart stale-routes-time 100

Use the clear ipv6 bgp neighbor command with the all parameter for the changes to the graceful restart parameters to take effect immediately.

Parent topic: BGP4+ graceful restart