ip ospf dead-interval

This command sets the OSPF dead interval for the specified interface or range of interfaces. The value for seconds (range: 1-65535) is a valid positive integer, which represents the length of time in seconds that a router's Hello packets have not been seen before its neighbor routers declare that the router is down. The value for the length of time must be the same for all routers attached to a common network. This value should be some multiple of the Hello Interval (i.e. 4). Valid values range in seconds from 1 to 65535.