What are the default Hello and Dead timers for OSPF Non-broadcast network type?

In OSPF (Open Shortest Path First) configuration for non-broadcast multi-access (NBMA) networks, the default Hello and Dead timers are critical for establishing and maintaining neighbor relationships. The Hello timer is set to 30 seconds, and the Dead timer is set to 120 seconds.

The Hello timer is the interval at which OSPF routers send Hello packets to discover and keep track of neighboring routers. A neighbor is considered down if no Hello packets are received within the Dead interval. Setting the Dead timer to 120 seconds ensures that if no Hello packets are received for this duration, the neighbor relationship will be declared down, allowing for more reliable network operation and topology maintenance.

These specific timers help to balance network stability and responsiveness. In non-broadcast environments, where routers do not automatically detect each other (as opposed to broadcast networks), these timers are especially important. The specified values allow for appropriate detection of connectivity issues without being too aggressive, which could overload the network with unnecessary traffic or cause needless disruption in the routing process.

Understanding these timers and their significance is essential for effective OSPF configuration and network performance optimization.