This read-write value, 1 to 360 seconds, sets how often this interface sends OSPF Hello packets, and it must be configured identically on all routers attached to the same common network. A smaller value detects topology changes faster but generates more OSPF protocol overhead, while a larger value reduces overhead at the cost of slower failure detection. For example, if a neighboring OSPF router on this LAN segment uses a 10-second Hello interval, this object must also be set to 10 or the adjacency will fail to form.