Both OSPFv2 and OSPFv3 support the graceful restart helper function which provides an OSPF neighbor a grace period during a control plane restart to minimize service disruption. When the control plane of a GR-capable router fails or restarts, the neighboring routers supporting the graceful restart helper mode (GR helpers) temporarily preserve OSPF forwarding information. Traffic continues to be forwarded to the restarting router using the last known forwarding tables. If the control plane of the restarting router comes back up within the grace period, the restarting router resumes normal OSPF operation. If the grace period expires, then the restarting router is presumed to be inactive and the OSPF topology is recalculated to route traffic around the failure.