06-15-2010, 07:08 PM
the route isnt learned because if it did it would make a routing loop. ospf is a link state routing protocol so each router comes up with its routing table based on its own SFP algorithm. The RT1 router sent the LSA to the RT2 router (with the route 0.0.0.0 0.0.0.0 serial 0/0 *172.16.100.1*) this IP is all ready known by the the RT2 router so it doesn't add it to the routing table.