What is the maximum number of OSPF areas allowed per router?

The maximum number of OSPF areas allowed per router is indeed 65535. OSPF (Open Shortest Path First) is a link-state routing protocol used for IP networks, and one of its design features is the ability to segment networks into areas. This ability helps manage routing information, allowing for a more scalable and efficient network.

Each OSPF router can participate in multiple areas, and the overall architecture allows for a large number of areas, thus helping in reducing routing overhead and improving efficiency. The OSPF area numbers are defined as 16-bit values, meaning they can range from 0 to 65535, which corresponds to the total of 65536 possible values, but area zero is reserved for the backbone area (Area 0). Therefore, the maximum practical number of areas that can be assigned to a router is 65535.

Understanding this limit is important when designing large OSPF networks to ensure optimal routing and management of network resources. The scalability provided through the use of numerous areas allows for effective distribution of routing information while minimizing the size of the routing table in OSPF-compatible devices.