[nsp] OSPF problem (LONG)

From: Eric J Merkel (merkel@defnet.com)
Date: Tue Jan 04 2000 - 16:43:13 EST


First of all, I must admit I am not well versed at ospf, so I
appreciate any pointers or help I can get.

I'm having problems getting OSPF to come up on a couple of routers.
What I am trying to do is create a ring topology using OSPF for
redundancy should one of the links go down. BTW, each router A-E
is connected to each other in the following manner via T1 and also
has one or more ethernet segments coming off of it.

C-----E
| |
| |
B D
 \ /
  \ /
   A

All of the serial links and one ethernet interface (A) are in Area 0.
Routers A, B, & D are exchanging routes just fine.

Link A-B 208.35.23.4/30 A/S0=208.35.23.5 B/S0=208.35.23.6
Link A-D 208.35.23.0/30 A/S0=208.35.23.1 D/S0=208.35.23.2

When I try to bring up the link between B-C,

Link B-C 208.35.23.12/30 B/S1=208.35.23.13 D/S0=208.35.23.14

I get the following error message on router C:

OSPF: Rcv pkt from 208.35.23.13, Serial0/0, area 0.0.0.0
      mismatch area 0.0.0.3 in the header

I get the following error message on router B (** Note that router B's
ethernet interface is in Area 3.):

%OSPF-4-ERRRCV: Received invalid packet: mismatch area ID, from backbone
area must be virtual-link but not found from 208.35.23.14, Serial1

It sounds like router B is not setting the serial link to be part of
area 0 and telling router C it's part of area 3 instead of 0. Here
is the ospf statement for the B and C routers.

B:

router ospf 100
 network 208.35.23.4 0.0.0.3 area 0
 network 208.228.56.128 0.0.0.127 area 3
 network 208.35.23.12 0.0.0.3 area 0

C:

router ospf 100
 network 208.35.23.12 0.0.0.3 area 0

Any suggestions? Yes, I do have 'ip classless' and 'ip subnet-zero' on the
routers.

Eric
Eric Merkel / MetaLink Technologies, Inc
~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*
Email: merkel@metalink.net
Phone: 419-782-3472 X304
~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*



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