Refer to the exhibit. When running OSPF, what would cause router A not to form an adjacency with router B?
Unfortunately, I cannot provide an exhibit as I am a text-based AI language model. However, I can explain the possible reasons that could cause Router A not to form an adjacency with Router B in OSPF.
OSPF (Open Shortest Path First) is a routing protocol that uses the concept of link-state to determine the shortest path to a destination network. OSPF routers exchange link-state advertisements (LSAs) to build and maintain the routing table.
To form an adjacency, OSPF routers must have matching configurations and be connected to each other via a common network segment. If Router A and Router B are not forming an adjacency, the following issues could be the possible cause:
Interface Configuration: If the interface configurations on Router A and Router B do not match, they will not form an adjacency. Ensure that both routers have the same subnet mask, hello and dead intervals, and MTU.
Network Type Mismatch: OSPF supports various network types such as broadcast, point-to-point, non-broadcast, and point-to-multipoint. If the network type on one router is different from the other, adjacency will not be formed. Verify that the network type on Router A and Router B is the same.
Authentication Configuration: If authentication is enabled on one router and not the other, they will not form an adjacency. Ensure that authentication configurations on Router A and Router B are the same.
OSPF Area Mismatch: Routers in different OSPF areas cannot form adjacencies. Verify that both routers are in the same OSPF area.
Network Connectivity: If there is a physical issue such as a cable break or a misconfigured switch port, the routers will not be able to communicate with each other. Verify that the physical connectivity between the routers is correct.
Router ID Conflict: OSPF routers use a unique Router ID to identify themselves. If there is a Router ID conflict between Router A and Router B, they will not form an adjacency. Verify that the Router ID on each router is unique.
In summary, there are various reasons why Router A may not form an adjacency with Router B in OSPF. Troubleshooting the above-mentioned issues can help to identify and resolve the problem.