Configure Graceful Restart

Graceful restart allows a router whose VPN control plane is undergoing a restart to continue to forward traffic while recovering its state from neighboring routers. Without graceful restart, a control plane restart disrupts any VPN services provided by the router. Graceful restart is supported on Layer 2 VPNs, Layer 3 VPNs, and virtual-router routing instances. It is not available for VPLS.

For VPN graceful restart to function properly, the following needs to be configured on the PE router:

• BGP graceful restart must be active on the PE-to-PE sessions carrying any service signaling data in the session's network layer reachability information (NLRI).
• OSPF, ISIS, LDP, and RSVP graceful restart must be active, because routes added by these protocols are used to resolve VPN NLRIs.
• For other protocols (static, RIP, OSPF, LDP, and so on), graceful restart functionality must also be active when these protocols are run between the PE and CE routers. Layer 2 VPNs do not rely on this because protocols are not configured between the PE and CE routers.

To enable VPN graceful restart, include the graceful-restart statement at the [edit routing-options] hierarchy level on the PE router:

[edit routing-options]

graceful-restart {...}

Also include the graceful-restart statement at the [edit routing-instances routing-instance-name routing-options] hierarchy level on the PE router:

[edit routing-instances routing-instance-name routing-options]

graceful-restart {...}