""p b"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Consider the following topology: > > area_0---ABR_1----area_1-----ABR_2----area_0 > > There are two area 0's.
CL: you have a partitioned area 0. can't have two area zeros in ospf. to quote from my favorite movie of all time, "There can be only one!!!!" > ABR_1 and ABR_2 will generate > type 3 summary LSAs for the respective area 0s and > flood the information into area_1. An internal > router in area 1 will see the summary LSAs from ABR_1 > and ABR_2, determine the best routes, and then insert > them into it's routing table. > > Now consider ABR_1. It sees and stores in it's area 1 > LSDB the summary LSAs it got from ABR_2. > > The OSPF spec indicates that ABR_1, however, should > not forward this routing information into it's own area 0 > connection. This is done to prevent routing loops. > > My question is this: What is the reason why ABR_1 can > not use the routing information learned via ABR_2's > summary LSA and install these routes into it's own > routing table? CL: there can be only one area zero. them's the rules. > > Note, I believe if there was a virtual link between ABR_1 > and 2, ABR_1 would learn via ABR_2 the same set of routes via > summary LSAs and would be allowed to enter them into it's > routing table. > > There must be a routing loop issue here, but don't see > it. CL: interarea routing must transit area 0. what you are not seeing is that you have a partitioned area zero, not two area zero's. you have broken ospf, and now you need to repair it. > > Thanks Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=57991&t=57990 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
