Configuring OSPF GR
GR ensures forwarding continuity when a routing protocol restarts or an active/standby switchover occurs.
Two routers are required to complete a GR process. The following are router roles in a GR process:
GR restarter—Graceful restarting router. It must have GR capability.
GR helper—A neighbor of the GR restarter. It helps the GR restarter to complete the GR process.
OSPF GR has the following types:
IETF GR—Uses Opaque LSAs to implement GR.
Non-IETF GR—Uses link local signaling (LLS) to advertise GR capability and uses out of band synchronization to synchronize the LSDB.
A device can act as a GR restarter and GR helper at the same time.