CCNP Routing and Switching ROUTE 300-101 Official Cert Guide

OSPF Neighbors and Adjacencies on LANs

Lesson 2: OSPF Neighbor Formation

With EIGRP, neighborship is relatively simple, if two EIGRP routers discover each other (using Hellos) and meet several requirements (like being in the same subnet). After becoming neighbors, the two EIGRP routers exchange topology information.

Comparing OSPF and EIGRP, OSPF neighborship is more complex. First, with EIGRP, two routers either become neighbors or they do not. With OSPF, even after all the neighbor parameter checks pass, two classes of neighborships exist: neighbors and fully adjacent neighbors. The OSPF neighbor discovery process has many pitfalls when the ...