- Bronze, 100 points or more
Well this is weird....or is it?
The backbone area is a 10.4.4.0/24 token ring segment; consisting of Routers F, G, H (whose RID's are 22.214.171.124, ...7.1 and ...8.1 respectively). Router F is the ABR to Area 1 via a serial link 126.96.36.199/30. (Router A is at the other end and there's nothing else in Area 1.)
Router H, meanwhile is the ABR to Area 2; via the serial 188.8.131.52 network. Router J is at the other end of that link and there is nothing else in that area.
Router J was the last to join, because I wanted to witness the arrival of Type 3 LSA's from the backbone. I booted up Router J, configured it (Serial 1 is 184.108.40.206; obviously .5 at Router H's end) for OSPF, enabled debug ip ospf spf (intra, inter, and external), and finally enabled the interface.
The debug output is in the attached .txt file.
My questions are these:
1. On line 3, what does "type 3" refer to? It can't (in my mind) refer to the LSA type, because a)later on, there's a type 0; and b)the link is 220.127.116.11, to which the router is directly connected. Why would an area-internal route appear as a Type 3 LSA?
2. On line 7, what does "type 0" mean?
3. Why is it ever saying "ABR not reachable 18.104.22.168"?? That router is its only neighbor, the only reason it's even getting LSA's. Why would it be called " not reachable?"
4. I notice there is a "delete list." What are the criteria for being placed on the delete list; and why are so many of the routes/links that Router J is first learning about being placed on the delete list so promptly?