Route missing in OSPF Topological Database

From: Hunt Lee (ciscoforme3@xxxxxxxxxxxx)
Date: Sat Aug 24 2002 - 09:53:10 GMT-3


   
Here is a partial diagram:

                       51.51.0.1/26
                          /
                         /
1.1.1.1/32 -- RTA --- RTB --- 2.2.2.2/32
                         \
                          \
                       100.100.100.1/32

N.B: The link connecting between RTA & RTB is 172.16.1.0/24

At RTB:-

router ospf 2
 log-adjacency-changes
 redistribute eigrp 1 subnets
 network 2.2.2.2 0.0.0.0 area 2
 network 51.0.0.0 0.255.255.255 area 0
 network 100.100.100.1 0.0.0.0 area 2
 network 172.16.1.0 0.0.0.255 area 0

At RTA:-

router ospf 1
 router-id 1.1.1.1
 log-adjacency-changes
 network 1.1.1.1 0.0.0.0 area 0
 network 172.16.1.0 0.0.0.255 area 0
 distance ospf intra-area 30 inter-area 20 external 50

Here is what I don't understand :( RTB has a loopback interface
(51.51.0.1/26), which is advertised to RTA as O (Intra-Area route).
RTA can see this route in it's Routing Table, & can ping it too!!
But I just can't find it in RTA's OSPF Topological database. But if
the route is not in RTA's OSPF database, how does it get learned by
RTA in the first place??

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

     51.0.0.0/26 is subnetted, 1 subnets
C 51.51.0.0 is directly connected, Loopback1
     1.0.0.0/32 is subnetted, 1 subnets
O 1.1.1.1 [110/11] via 172.16.1.1, 00:01:17, Ethernet0
     2.0.0.0/32 is subnetted, 1 subnets
C 2.2.2.2 is directly connected, Loopback0
     100.0.0.0/32 is subnetted, 1 subnets
C 100.100.100.1 is directly connected, Loopback2
     3.0.0.0/24 is subnetted, 1 subnets
D 3.3.3.0 [90/2297856] via 10.1.1.6, 00:03:41, Serial0
     172.16.0.0/24 is subnetted, 1 subnets
C 172.16.1.0 is directly connected, Ethernet0
     10.0.0.0/30 is subnetted, 1 subnets
C 10.1.1.4 is directly connected, Serial0
RouterB#

And I can see the route 51.51.0.0/26 in RTA's Routing Table..

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

     51.0.0.0/26 is subnetted, 1 subnets
O 51.51.0.0 [30/11] via 172.16.1.2, 00:02:01, Ethernet0
     1.0.0.0/18 is subnetted, 1 subnets
C 1.1.0.0 is directly connected, Loopback0
     2.0.0.0/32 is subnetted, 1 subnets
O IA 2.2.2.2 [20/11] via 172.16.1.2, 00:02:01, Ethernet0
     100.0.0.0/32 is subnetted, 1 subnets
O IA 100.100.100.1 [20/11] via 172.16.1.2, 00:02:01, Ethernet0
     3.0.0.0/24 is subnetted, 1 subnets
O E2 3.3.3.0 [50/20] via 172.16.1.2, 00:02:01, Ethernet0
     172.16.0.0/24 is subnetted, 1 subnets
C 172.16.1.0 is directly connected, Ethernet0
     10.0.0.0/30 is subnetted, 1 subnets
O E2 10.1.1.4 [50/20] via 172.16.1.2, 00:02:03, Ethernet0

RouterA#ping 51.51.0.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 51.51.0.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/8 ms

But the route is not in RTA's OSPF Database...

RouterA#sh ip ospf database

            OSPF Router with ID (1.1.1.1) (Process ID 1)

                Router Link States (Area 0)

Link ID ADV Router Age Seq# Checksum Link count
1.1.1.1 1.1.1.1 951 0x80000005 0xB7D2 2
100.100.100.1 100.100.100.1 231 0x80000009 0xEFC 2

                Net Link States (Area 0)

Link ID ADV Router Age Seq# Checksum
172.16.1.2 100.100.100.1 957 0x80000001 0x31E8

                Summary Net Link States (Area 0)

Link ID ADV Router Age Seq# Checksum
2.2.2.2 100.100.100.1 975 0x80000002 0xC53F
100.100.100.1 100.100.100.1 975 0x80000002 0xF9E4

                Type-5 AS External Link States

Link ID ADV Router Age Seq# Checksum Tag
3.3.3.0 100.100.100.1 976 0x80000002 0xA5E 0
10.1.1.4 100.100.100.1 977 0x80000002 0xA2C1 0
RouterA#

Any ideas will be greatly appreciated.

Best Regards,
Hunt

http://digital.yahoo.com.au - Yahoo! Digital How To
- Get the best out of your PC!



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