From: Omkar Tambalkar (omkar.groupstudy@gmail.com)
Date: Thu Oct 23 2008 - 21:46:25 ARST
In this lab there are 2 ABRs for the NSSA but lab asks you to hard-code the
router-ids on one of the ABRs so that it becomes the router to convert the
Type 7 LSA received by the NSSA ASBR in Type 5 LSA to be advertised into
area 0.
My area 0 router database shows that it is learning the external route by
the ABR that was hard-coded to advertise the Type 5 LSA but shows that the
route is reachable via both ABRs in the routing table. Why would it install
the route from the other ABR when its LSDB does not contain that route as
being advertised by that ABR?
LSDB section for External routes on Area 0 router:
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
160.1.50.0 155.1.0.5 1905 0x80000005 0x00E442 0
160.1.60.0 200.200.200.200 129 0x80000004 0x00B642 0
---------------->ABR supposed to advertise the external route
Rack1R5#
Routing table of Area 0 router:
Rack1R5#sh ip route ospf
155.1.0.0/24 is subnetted, 2 subnets
O IA 155.1.146.0 [110/74] via 155.1.0.4, 00:32:59, Serial0/0
[110/74] via 155.1.0.1, 00:32:59, Serial0/0
160.1.0.0/24 is subnetted, 2 subnets
O E2 160.1.60.0 [110/20] via 155.1.0.1, 00:32:59, Serial0/0
----------------------> should be only this route
[110/20] via 155.1.0.4, 00:32:59, Serial0/0
----------------------> why are you here also?
150.1.0.0/16 is variably subnetted, 4 subnets, 2 masks
O IA 150.1.6.6/32 [110/75] via 155.1.0.4, 00:32:59, Serial0/0
[110/75] via 155.1.0.1, 00:32:59, Serial0/0
O IA 150.1.4.4/32 [110/65] via 155.1.0.4, 00:32:59, Serial0/0
O IA 150.1.1.1/32 [110/65] via 155.1.0.1, 00:32:59, Serial0/0
Also the second ABR of the NSSA has the Type 7 LSA received by the ASBR of
the NSSA but when it installs the external route in its routing table, it
installs it as E2 external route, why does it prefer the E2 route instead of
N2 route, is it because the E2 route is coming from the other ABR as a
external route via its interface in area 0
IP routing table of the second ABR of NSSA:
O E2 160.1.60.0 [110/20] via 155.1.146.6, 00:35:07, Ethernet0/0
-------------> advertised as E2
- Later,
Omkar
Blogs and organic groups at http://www.ccie.net
This archive was generated by hypermail 2.1.4 : Sat Nov 01 2008 - 15:35:22 ARST