What is the default hello interval for OSPF?

The default hello interval for OSPF (Open Shortest Path First) is indeed 10 seconds. This interval is critical because OSPF routers use hello packets to establish and maintain adjacency with neighboring routers. The hello packets are sent at this default interval to ensure that routers can detect the presence of neighbors and can quickly respond to any changes in the network topology.

Setting the hello interval to 10 seconds strikes a balance between responsiveness in discovering neighbors and the efficient use of network resources. If a router does not receive a hello packet from a neighbor within a certain timeframe, it will assume that the neighbor is down and take appropriate actions to reroute traffic, thus ensuring network continuity.

Interestingly, this value can be customized on a per-interface basis to suit different network conditions or design requirements, but the industry standard and default is 10 seconds. Understanding this concept is vital for network engineers working with OSPF, as it directly impacts the OSPF network behavior and stability.