OSPF graceful shutdown

From CT3

The OSPF Stub Router Advertisement feature introduced in IOS releases 12.0S, 12.2T and 12.3 allow you to gracefully remove an OSPF router from the network without impacting the existing traffic flows.

The OSPF Graceful Shutdown IOS feature abruptly terminates OSPF adjacencies and thus only reduces the time it takes to detect neighbor outage.

The OSPF router on which you configure the max-metric router-lsa OSPF configuration command advertises very high cost for all its inter-router links, causing all traffic that could be rerouted across alternate paths to avoid the router. Optionally, you could change the cost for the router’s stub networks or inter-area routes advertised by the router. After the network has converged around the very high cost links, you can safely remove the router from the network (or reload/upgrade it).