What impact does a mismatch in OSPF network type have on neighboring routers?

When there is a mismatch in OSPF (Open Shortest Path First) network types between neighboring routers, they will indeed form an adjacency but will not learn routes from one another. OSPF network types include broadcast, non-broadcast multi-access (NBMA), point-to-point, and point-to-multipoint, among others. Each type of network has specific characteristics that influence how OSPF operates.

In scenarios where there is a mismatch, such as one router configured for a broadcast network while the other is set for a point-to-point network, OSPF will still establish an adjacency through the OSPF process because both routers can communicate at the link layer and recognize each other as neighbors. However, routing table updates are dependent on the proper configuration and understanding of OSPF through the concept of different network types. Since the configuration does not align, they won’t properly synchronize their routing information, which leads to the situation where they will not learn routes from each other.

This lack of route learning highlights the importance of matching network types when configuring OSPF to ensure full adjacency and communication of routing information between routers.