OSPF discontinuous area 0 (IpExpert lab 5)

From: George Goglidze (goglidze@gmail.com)
Date: Sat Sep 29 2007 - 15:44:38 ART


Hello all,

I'm doing ipexpert-s lab number 5. and they have discontinuous ospf area 0.

the topology is the following:

R2 FR hub.
R6, R4 FR spokes.

R2 F0/0 interface is in area 0, and FR interface that connects to R4 and R6
is in area 246.

R6 has area 0 too on other interface, let's say int Multilink 1.

when I have interface Multilink 1 in shutdown.
I do receive routes to other areas that are accessible through R2.
but when it's UP, the routes disappear.

------
here's some config:
------------------------------

R2:

router ospf 1
 router-id 2.2.2.2
 log-adjacency-changes
 area 0 authentication message-digest
 area 25 virtual-link 5.5.5.5
 network 2.2.2.0 0.0.0.255 area 0
 network 20.2.2.0 0.0.0.255 area 246
 network 21.2.2.0 0.0.0.255 area 25
 network 150.50.12.0 0.0.0.255 area 0
 network 150.50.25.0 0.0.0.255 area 25
 network 150.50.246.0 0.0.0.255 area 246

interface Serial2/0.1 multipoint
 ip address 150.50.246.2 255.255.255.0
 no ip split-horizon
 ip ospf network broadcast
 ip ospf priority 10
 frame-relay map ip 150.50.246.2 204
 frame-relay map ip 150.50.246.4 204 broadcast
 frame-relay map ip 150.50.246.6 206 broadcast

------------

R6 config
----------------------

router ospf 1
 router-id 6.6.6.6
 log-adjacency-changes
 area 0 authentication message-digest
 network 6.6.6.0 0.0.0.255 area 246
 network 61.6.6.0 0.0.0.255 area 0
 network 150.50.69.0 0.0.0.255 area 0
 network 150.50.246.0 0.0.0.255 area 246

interface Serial2/0
 ip address 150.50.246.6 255.255.255.0
 encapsulation frame-relay
 ip ospf network broadcast
 ip ospf priority 0
 serial restart-delay 0
 no dce-terminal-timing-enable
 no arp frame-relay
 frame-relay map ip 150.50.246.2 602 broadcast
 frame-relay map ip 150.50.246.4 602 broadcast
 frame-relay map ip 150.50.246.6 602
 no frame-relay inverse-arp

interface Multilink1
 ip address 150.50.69.6 255.255.255.0
 ip ospf message-digest-key 1 md5 7 0502160A395C4B1B0D
 shutdown
 ppp multilink
 ppp multilink group 1

As I know I should be ok with discontinuous area 0. but why does it not
work???

here's the routing table when Multilink 1 is in shutdown.

R6#sh ip route
Codes: C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, 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 IA 1.1.1.1 [110/66] via 150.50.246.2, 00:01:00, Serial2/0
     2.0.0.0/32 is subnetted, 1 subnets
O IA 2.2.2.2 [110/65] via 150.50.246.2, 00:01:00, Serial2/0
     4.0.0.0/32 is subnetted, 1 subnets
O 4.4.4.4 [110/65] via 150.50.246.4, 00:20:59, Serial2/0
     21.0.0.0/32 is subnetted, 1 subnets
O IA 21.2.2.2 [110/65] via 150.50.246.2, 00:01:00, Serial2/0
     20.0.0.0/32 is subnetted, 1 subnets
O 20.2.2.2 [110/65] via 150.50.246.2, 00:20:59, Serial2/0
     5.0.0.0/32 is subnetted, 1 subnets
O IA 5.5.5.5 [110/129] via 150.50.246.2, 00:01:00, Serial2/0
     6.0.0.0/24 is subnetted, 1 subnets
C 6.6.6.0 is directly connected, Loopback0
     172.4.0.0/24 is subnetted, 4 subnets
O 172.4.0.0 [110/65] via 150.50.246.4, 00:21:00, Serial2/0
O 172.4.1.0 [110/65] via 150.50.246.4, 00:21:00, Serial2/0
O 172.4.2.0 [110/65] via 150.50.246.4, 00:21:00, Serial2/0
O 172.4.3.0 [110/65] via 150.50.246.4, 00:21:00, Serial2/0
     10.0.0.0/32 is subnetted, 1 subnets
O IA 10.1.1.1 [110/66] via 150.50.246.2, 00:01:01, Serial2/0
     61.0.0.0/24 is subnetted, 1 subnets
C 61.6.6.0 is directly connected, Loopback1
     150.50.0.0/16 is variably subnetted, 5 subnets, 2 masks
C 150.50.246.0/24 is directly connected, Serial2/0
C 150.50.7.0/25 is directly connected, FastEthernet0/0
O IA 150.50.1.0/24 [110/66] via 150.50.246.2, 00:01:01, Serial2/0
O IA 150.50.12.0/24 [110/65] via 150.50.246.2, 00:01:01, Serial2/0
O IA 150.50.25.0/24 [110/128] via 150.50.246.2, 00:01:01, Serial2/0

and here's the sh ip route when it's up:

R6#sh ip route
Codes: C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, 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

     4.0.0.0/32 is subnetted, 1 subnets
O 4.4.4.4 [110/65] via 150.50.246.4, 00:21:25, Serial2/0
     20.0.0.0/32 is subnetted, 1 subnets
O 20.2.2.2 [110/65] via 150.50.246.2, 00:21:25, Serial2/0
     6.0.0.0/24 is subnetted, 1 subnets
C 6.6.6.0 is directly connected, Loopback0
     172.4.0.0/24 is subnetted, 4 subnets
O 172.4.0.0 [110/65] via 150.50.246.4, 00:21:25, Serial2/0
O 172.4.1.0 [110/65] via 150.50.246.4, 00:21:25, Serial2/0
O 172.4.2.0 [110/65] via 150.50.246.4, 00:21:25, Serial2/0
O 172.4.3.0 [110/65] via 150.50.246.4, 00:21:25, Serial2/0
     61.0.0.0/24 is subnetted, 1 subnets
C 61.6.6.0 is directly connected, Loopback1
     150.50.0.0/16 is variably subnetted, 4 subnets, 3 masks
C 150.50.246.0/24 is directly connected, Serial2/0
C 150.50.7.0/25 is directly connected, FastEthernet0/0
C 150.50.69.0/24 is directly connected, Multilink1
C 150.50.69.9/32 is directly connected, Multilink1

all the IA routes dissapeared.

Many thanks for any help,



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