3.6.f Implement and troubleshoot operations

3.6.f [i] General operations

The most common reasons for OSPF neighborship to not form are:

● MTU mismatch

● Area type mismatch

● Network type mismatch

Adam, Paul (2014-07-12). All-in-One CCIE V5 Written Exam Guide (Kindle Locations 3568-3572).  . Kindle Edition.

http://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/12151-trouble-main.html#trouble_neigh_states