NSSA and type 7 LSA's

From: Keith Steller (ksteller@attbi.com)
Date: Mon Sep 02 2002 - 12:26:55 GMT-3


Hello All-

I have a question for someone. I have an NSSA configured to allow
redistibution of a few RIP routes into the OSPF net. I have everything
working fine except for one thing. I can see the RIP routes, denoted by the
N2 in the routing table on the ABR where the "Area X NSSA" is configured. I
dont see those type 7 routes being advertised to other routers in the OSPF
network though. I'm wondering if that's correct behavior. I can get
connectivity to the RIP net (146.10.18.x) when I add the "default
information originate always" on the ABR with the NSSA, as he can see the
RIP routes from there. With that configured, everyone sends packets to him
when they dont have a route available. Shouldnt the NSSA allow the RIP
network to be advrtised to all routers in the OSPF network? I attached the
configs below. R1 is the ASBR with RIP and OSPF. R2 is the other end of the
NSSA ABR (connected to Area 0), and R5 is also on th backbone on area 0.

Thanks for the assistance,

Keith

R1
!
router ospf 100
 redistribute rip subnets
 passive-interface TokenRing0
 network 146.10.11.0 0.0.0.255 area 11
 network 146.10.21.0 0.0.0.3 area 21
 default-metric 5
 area 11 range 146.10.11.0 255.255.255.0
 area 21 nssa
!
router rip
 version 1
 redistribute ospf 100 metric 10
 passive-interface Loopback100
 passive-interface Serial1
 network 146.10.0.0
 neighbor 146.10.18.8
!
r1#sh ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
       i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate
default
       U - per-user static route, o - ODR

Gateway of last resort is 146.10.21.2 to network 0.0.0.0

     146.10.0.0/16 is variably subnetted, 6 subnets, 2 masks
C 146.10.18.0/24 is directly connected, TokenRing0
C 146.10.21.0/30 is directly connected, Serial1
C 146.10.11.0/24 is directly connected, Loopback100
R 146.10.88.0/24 [120/1] via 146.10.18.8, 00:00:17, TokenRing0
R 146.10.78.0/24 [120/1] via 146.10.18.8, 00:00:17, TokenRing0
C 146.10.118.0/24 is directly connected, Loopback200
O*IA 0.0.0.0/0 [110/65] via 146.10.21.2, 00:12:41, Serial1
r1#
***************************************
R2
!
router ospf 100
 network 146.10.10.0 0.0.0.255 area 0
 network 146.10.21.0 0.0.0.3 area 21
 network 146.10.22.0 0.0.0.255 area 22
 neighbor 146.10.10.6 priority 1
 neighbor 146.10.10.5 priority 5
 default-information originate always
 area 21 nssa default-information-originate no-summary
 area 22 range 146.10.22.0 255.255.255.0
!

r2#sh ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
       i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate
default
       U - per-user static route, o - ODR

Gateway of last resort is not set

     146.10.0.0/16 is variably subnetted, 12 subnets, 3 masks
C 146.10.24.0/24 is directly connected, Serial0.1
O N2 146.10.18.0/24 [110/5] via 146.10.21.1, 00:14:30, Serial1
C 146.10.21.0/30 is directly connected, Serial1
C 146.10.22.0/24 is directly connected, Loopback100
C 146.10.10.0/24 is directly connected, Serial0
O N2 146.10.11.0/24 [110/5] via 146.10.21.1, 00:14:30, Serial1
O IA 146.10.57.0/25 [110/74] via 146.10.10.6, 00:14:30, Serial0
                       [110/74] via 146.10.10.5, 00:14:30, Serial0
O IA 146.10.55.0/24 [110/65] via 146.10.10.5, 00:14:30, Serial0
O N2 146.10.88.0/24 [110/5] via 146.10.21.1, 00:14:30, Serial1
O N2 146.10.78.0/24 [110/5] via 146.10.21.1, 00:14:30, Serial1
O IA 146.10.66.0/24 [110/65] via 146.10.10.6, 00:14:30, Serial0
O N2 146.10.118.0/24 [110/5] via 146.10.21.1, 00:14:30, Serial1
r2#
Type-7 AS External Link States (Area 21)

Link ID ADV Router Age Seq# Checksum Tag
146.10.11.0 146.10.118.1 445 0x80000002 0xF944 0
146.10.18.0 146.10.118.1 445 0x80000002 0xAC8A 0
146.10.21.0 146.10.118.1 445 0x80000002 0x79BD 0
146.10.78.0 146.10.118.1 445 0x80000002 0x16E4 0
146.10.88.0 146.10.118.1 445 0x80000002 0xA749 0
146.10.118.0 146.10.118.1 445 0x80000002 0x5C76 0
****************************************************
R5
!
router ospf 100
 network 146.10.10.0 0.0.0.255 area 0
 network 146.10.55.0 0.0.0.255 area 55
 network 146.10.57.0 0.0.0.127 area 57
 neighbor 146.10.10.2 priority 10
 area 55 range 146.10.55.0 255.255.255.0
!
r5#sh ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
       i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate
default
       U - per-user static route, o - ODR

Gateway of last resort is 146.10.10.2 to network 0.0.0.0

     146.10.0.0/16 is variably subnetted, 6 subnets, 3 masks
O IA 146.10.21.0/30 [110/128] via 146.10.10.2, 00:16:28, Serial0.501
O IA 146.10.22.0/24 [110/65] via 146.10.10.2, 00:16:28, Serial0.501
C 146.10.10.0/24 is directly connected, Serial0.501
C 146.10.57.0/25 is directly connected, Ethernet0
C 146.10.55.0/24 is directly connected, Loopback55
O IA 146.10.66.0/24 [110/65] via 146.10.10.6, 00:16:28, Serial0.501
     146.100.0.0/24 is subnetted, 1 subnets
C 146.100.55.0 is directly connected, Loopback100
O*E2 0.0.0.0/0 [110/1] via 146.10.10.2, 00:16:21, Serial0.501
r5#



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