Configuring BGP4+ graceful restart

The graceful restart (GR) feature can be configured on a routing device, providing it with the capability to inform its neighbors when it is performing a restart.

About this task

Note

High availability (HA) requires GR to be enabled.

Procedure

Enter the configure terminal command to access global configuration mode.
```
device# configure terminal
```
Enter the router bgp command to enable BGP routing.
```
device(config)# router bgp
```
Enter the local-as command to configure the autonomous system number (ASN) in which your device resides.
```
device(config-bgp-router)# local-as 1000
```
Enter the neighbor remote-as command, specifying an IPv6 address, to specify the autonomous system ASN in which the remote neighbor resides.
```
device(config-bgp-router)# neighbor 1000::1 remote-as 2
```
Enter the address-family ipv6 unicast command to enter IPv6 address family configuration mode.
```
device(config-bgp-router)# address-family ipv6 unicast
```
Enter the neighbor activate command to add a neighbor.
```
device(config-bgp-ipv6u)# neighbor 1000::1 activate
```
Enter the graceful-restart command to enable the graceful restart feature.
```
device(config-bgp-ipv6u)# graceful-restart
```
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
```

Example

The following example 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

Example

The following example 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

Example

The following example 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

Example

The following example 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

What to do next

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