From: Mingzhou Nie (mnie@xxxxxxxxx)
Date: Tue Aug 06 2002 - 10:56:52 GMT-3
Remember, nssa is also a stub area with exception that it will allow
external routes redis in(RTC in your case), so external routes, or type
5 LSAs from other areas including area 0 is not allowed.
To workaround it, you either have to make RTC totally stubby or
generate a default route
RTC
router ospf 1
area 1 nssa default-information originate
--- Hunt Lee <ciscoforme3@yahoo.com.au> wrote:
> Okay folks, starting off some late nite studying and just bumped into
> another problem.
>
> 1.1.1.1/32 -- RTA -- RTB -- RTC -- RTD - 156.26.32.0/24 & 33.0/24
>
>
> Both RTA, B & C are using OSPF.
>
> RTA & RTB are in OSPF Area 0
> RTB & RTC are in NSSA Area 1
>
> RTC also uses RIP v2, so it's an ASBR
> And RTD uses RIPv2
>
> RTA's interface to RTB - 10.1.1.1
> RTB's interface back to RTA - 10.1.1.2
> RTB's interface to RTC - 10.1.1.5
> RTC's interface back to RTB - 10.1.1.6
> RTC's interface to RTD - 10.1.1.10
> RTD's interface back to RTC - 10.1.1.9
>
> RTD advertise the 2 networks 156.26.32.0/24 & 156.26.33.0/24 with
> RIPv2.
>
> RTC is doing mutual redistribution, where the RIPv2 is being
> redistributed into OSPF, and OSPF is being redistributed back into
> RIP.
>
> Here's my question, RTA has a Loopback interface (1.1.1.1/32) and it
> is being redistributed into OSPF at RTA:-
>
> router ospf 1
> log-adjacency-changes
> redistribute connected subnets
> network 10.1.1.0 0.0.0.3 area 0
>
> RouterA#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, ia - IS-IS
> inter area
> * - candidate default, U - per-user static route, o - ODR
> P - periodic downloaded static route
>
> Gateway of last resort is not set
>
> 1.0.0.0/32 is subnetted, 1 subnets
> C 1.1.1.1 is directly connected, Loopback0
> 156.26.0.0/24 is subnetted, 2 subnets
> O E2 156.26.32.0 [110/20] via 10.1.1.2, 01:36:22, Serial0
> O E2 156.26.33.0 [110/20] via 10.1.1.2, 01:36:22, Serial0
> 10.0.0.0/30 is subnetted, 3 subnets
> O E2 10.1.1.8 [110/20] via 10.1.1.2, 01:36:22, Serial0
> C 10.1.1.0 is directly connected, Serial0
> O IA 10.1.1.4 [110/128] via 10.1.1.2, 01:37:34, Serial0
> RouterA#
>
>
> And at RTB, I can still see the route (1.1.1.1/32) as O E2...
>
> RouterB#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, ia - IS-IS
> inter area
> * - candidate default, U - per-user static route, o - ODR
> P - periodic downloaded static route
>
> Gateway of last resort is not set
>
> 1.0.0.0/32 is subnetted, 1 subnets
> O E2 1.1.1.1 [110/20] via 10.1.1.1, 01:37:18, Serial0
> 2.0.0.0/32 is subnetted, 1 subnets
> C 2.2.2.2 is directly connected, Loopback0
> 156.26.0.0/24 is subnetted, 2 subnets
> O N2 156.26.32.0 [110/20] via 10.1.1.6, 01:37:18, Serial1
> O N2 156.26.33.0 [110/20] via 10.1.1.6, 01:37:18, Serial1
> 10.0.0.0/30 is subnetted, 3 subnets
> O N2 10.1.1.8 [110/20] via 10.1.1.6, 01:37:18, Serial1
> C 10.1.1.0 is directly connected, Serial0
> C 10.1.1.4 is directly connected, Serial1
> RouterB#
>
> But at RTC, the route disappears!!!
>
> RouterC#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, ia - IS-IS
> inter area
> * - candidate default, U - per-user static route, o - ODR
> P - periodic downloaded static route
>
> Gateway of last resort is not set
>
> 3.0.0.0/24 is subnetted, 1 subnets
> C 3.3.3.0 is directly connected, Loopback0
> 156.26.0.0/24 is subnetted, 2 subnets
> R 156.26.32.0 [120/1] via 10.1.1.9, 00:00:02, Serial1
> R 156.26.33.0 [120/1] via 10.1.1.9, 00:00:02, Serial1
> 10.0.0.0/30 is subnetted, 3 subnets
> C 10.1.1.8 is directly connected, Serial1
> O IA 10.1.1.0 [110/128] via 10.1.1.5, 01:38:50, Serial0
> C 10.1.1.4 is directly connected, Serial0
> RouterC#
>
> RouterB#sh ip ospf database
>
> OSPF Router with ID (2.2.2.2) (Process ID 2)
>
> Router Link States (Area 0)
>
> Link ID ADV Router Age Seq# Checksum Link count
> 1.1.1.1 1.1.1.1 1655 0x80000005 0x6B0D 2
> 2.2.2.2 2.2.2.2 984 0x80000008 0x867 2
>
> Summary Net Link States (Area 0)
>
> Link ID ADV Router Age Seq# Checksum
> 10.1.1.4 2.2.2.2 1728 0x80000004 0xF5EE
>
> Router Link States (Area 1)
>
> Link ID ADV Router Age Seq# Checksum Link count
> 2.2.2.2 2.2.2.2 984 0x80000009 0xC787 2
> 10.1.1.10 10.1.1.10 874 0x80000007 0x54EE 2
>
> Summary Net Link States (Area 1)
>
> Link ID ADV Router Age Seq# Checksum
> 10.1.1.0 2.2.2.2 984 0x80000006 0xBF21
>
> Type-7 AS External Link States (Area 1)
>
> Link ID ADV Router Age Seq# Checksum Tag
> 10.1.1.8 10.1.1.10 876 0x80000004 0x87D2 0
> 156.26.32.0 10.1.1.10 876 0x80000004 0xF49F 0
> 156.26.33.0 10.1.1.10 876 0x80000004 0xE9A9 0
>
> Type-5 AS External Link States
>
> Link ID ADV Router Age Seq# Checksum Tag
> 1.1.1.1 1.1.1.1 1657 0x80000004 0x95FF 0
> 10.1.1.8 2.2.2.2 985 0x80000004 0x85EC 0
> 156.26.32.0 2.2.2.2 985 0x80000004 0xF2B9 0
> 156.26.33.0 2.2.2.2 985 0x80000004 0xE7C3 0
> RouterB#
>
> RouterC#sh ip ospf database
>
> OSPF Router with ID (10.1.1.10) (Process ID 3)
>
> Router Link States (Area 1)
>
> Link ID ADV Router Age Seq# Checksum Link count
> 2.2.2.2 2.2.2.2 1136 0x80000009 0xC787 2
> 10.1.1.10 10.1.1.10 1024 0x80000007 0x54EE 2
>
> Summary Net Link States (Area 1)
>
> Link ID ADV Router Age Seq# Checksum
> 10.1.1.0 2.2.2.2 1136 0x80000006 0xBF21
>
> Type-7 AS External Link States (Area 1)
>
> Link ID ADV Router Age Seq# Checksum Tag
> 10.1.1.8 10.1.1.10 1024 0x80000004 0x87D2 0
> 156.26.32.0 10.1.1.10 1024 0x80000004 0xF49F 0
> 156.26.33.0 10.1.1.10 1024 0x80000004 0xE9A9 0
> RouterC#
>
>
> I always thought what NSSA does is to allow one to create a Stubby or
> Totally Stubby Area and also be able to advertise redistributed
> routes into / across this Stub Area. Did I missed something simple
> here??
>
> Thanks,
> H.
>
> http://digital.yahoo.com.au - Yahoo! Digital How To
> - Get the best out of your PC!
This archive was generated by hypermail 2.1.4 : Sat Sep 07 2002 - 19:48:17 GMT-3