Routing and switching

[Mlex1]

Hello everyone here i configured ospf multi-area here my question i couldn't see network 10.1.2.0/24 on R1 routing table. here all mu configuration, i done i few steps especially ospf virtual link anyway from R1 i couldn't ping R3 subnet 10.1.2.0/24 thanks in advance.

  

R1

interface GigabitEthernet0/0
no switchport
ip address 192.0.2.1 255.255.255.252
negotiation auto
!
interface GigabitEthernet0/1
no switchport
ip address 203.0.113.1 255.255.255.252
negotiation auto
!
interface GigabitEthernet0/2
no switchport
ip address 10.1.1.1 255.255.255.0
negotiation auto

!

router ospf 100
router-id 1.1.1.1
network 10.1.1.0 0.0.0.255 area 0
network 192.0.2.0 0.0.0.3 area 1
network 203.0.113.0 0.0.0.3 area 1

!

R2

interface GigabitEthernet0/0
no switchport
ip address 192.0.2.2 255.255.255.252
negotiation auto
!
interface GigabitEthernet0/1
no switchport
ip address 198.51.100.1 255.255.255.252
negotiation auto
!
interface GigabitEthernet0/2
no switchport
no ip address
negotiation auto

!

router ospf 200
router-id 2.2.2.2
area 1 virtual-link 3.3.3.3
network 192.0.2.0 0.0.0.3 area 1
network 198.51.100.0 0.0.0.3 area 1

!

R3

interface GigabitEthernet0/0
no switchport
ip address 198.51.100.2 255.255.255.252
negotiation auto
!
interface GigabitEthernet0/1
no switchport
ip address 203.0.113.2 255.255.255.252
negotiation auto
!
interface GigabitEthernet0/2
no switchport
ip address 10.1.2.1 255.255.255.0
negotiation auto
!

router ospf 300
router-id 3.3.3.3
area 1 virtual-link 2.2.2.2
network 10.1.2.0 0.0.0.255 area 2
network 198.51.100.0 0.0.0.3 area 1
network 203.0.113.0 0.0.0.3 area 1

!

R1 routing and neighbors 

Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 10.1.1.0/24 is directly connected, GigabitEthernet0/2
L 10.1.1.1/32 is directly connected, GigabitEthernet0/2
192.0.2.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.0.2.0/30 is directly connected, GigabitEthernet0/0
L 192.0.2.1/32 is directly connected, GigabitEthernet0/0
198.51.100.0/30 is subnetted, 1 subnets
O 198.51.100.0 [110/4000] via 203.0.113.2, 00:01:13, GigabitEthernet0/1
[110/4000] via 192.0.2.2, 00:01:13, GigabitEthernet0/0
203.0.113.0/24 is variably subnetted, 2 subnets, 2 masks
C 203.0.113.0/30 is directly connected, GigabitEthernet0/1
L 203.0.113.1/32 is directly connected, GigabitEthernet0/1
R1# show ip os
R1# show ip ospf ne
R1# show ip ospf neighbor

Neighbor ID Pri State Dead Time Address Interface
3.3.3.3 1 FULL/BDR 00:00:32 203.0.113.2 GigabitEthernet0/1
2.2.2.2 1 FULL/DR 00:00:36 192.0.2.2 GigabitEthernet0/0
R2 routing and neighbors 

10.0.0.0/24 is subnetted, 1 subnets
O IA 10.1.1.0 [110/4000] via 192.0.2.1, 00:00:15, GigabitEthernet0/0
192.0.2.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.0.2.0/30 is directly connected, GigabitEthernet0/0
L 192.0.2.2/32 is directly connected, GigabitEthernet0/0
198.51.100.0/24 is variably subnetted, 2 subnets, 2 masks
C 198.51.100.0/30 is directly connected, GigabitEthernet0/1
L 198.51.100.1/32 is directly connected, GigabitEthernet0/1
203.0.113.0/30 is subnetted, 1 subnets
O 203.0.113.0 [110/4000] via 198.51.100.2, 00:00:05, GigabitEthernet0/1
[110/4000] via 192.0.2.1, 00:00:15, GigabitEthernet0/0
R2#
R2#show ip os
R2#show ip ospf ne
R2#show ip ospf neighbor

Neighbor ID Pri State Dead Time Address Interface
3.3.3.3 1 FULL/BDR 00:00:38 198.51.100.2 GigabitEthernet0/1
1.1.1.1 1 FULL/BDR 00:00:37 192.0.2.1 GigabitEthernet0/0

R3 routing and neighbors 

ateway of last resort is not set

10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
O IA 10.1.1.0/24 [110/4000] via 203.0.113.1, 00:07:18, GigabitEthernet0/1
C 10.1.2.0/24 is directly connected, GigabitEthernet0/2
L 10.1.2.1/32 is directly connected, GigabitEthernet0/2
192.0.2.0/30 is subnetted, 1 subnets
O 192.0.2.0 [110/4000] via 203.0.113.1, 00:07:18, GigabitEthernet0/1
[110/4000] via 198.51.100.1, 00:07:18, GigabitEthernet0/0
198.51.100.0/24 is variably subnetted, 2 subnets, 2 masks
C 198.51.100.0/30 is directly connected, GigabitEthernet0/0
L 198.51.100.2/32 is directly connected, GigabitEthernet0/0
203.0.113.0/24 is variably subnetted, 2 subnets, 2 masks
C 203.0.113.0/30 is directly connected, GigabitEthernet0/1
L 203.0.113.2/32 is directly connected, GigabitEthernet0/1
R3#show ip ospf neighbor

Neighbor ID Pri State Dead Time Address Interface
1.1.1.1 1 FULL/DR 00:00:39 203.0.113.1 GigabitEthern1
2.2.2.2 1 FULL/DR 00:00:32 198.51.100.1 GigabitEthern0

[MHM Cisco World · Accepted solution]

the virtual-link must between R1 and R3 
not between R3-R2 and R1-R2 

[Mlex1]

how do you know ? hare please you knowledge 

[Spooster IT Services]

Hi Parvin , 

- The virtual - link must be created between R1 & R3 . The virtual - link is Always created between  Backbone area (Area 0)  & some other area ( Area 2 in your case )  .

- The purpose of creating a virtual-link is to make the other area ( Area 2 ) get connected to Area 0 , which didn't happen physically due to the topology so using a virtual- link we make that happen 

- in your scenario the issue was that there was no Virtual-link between R1 & R3 due to which R3 won't become an ABR , won't share LSA3  ( for a router to become ABR , they should have one interface in AREA =0  ) , Now if R3 won't become ABR , it won't share the prefixes of AREA 2 in AREA 1 and won't share the prefixes received from Area 0, 1 in AREA 2  

- Therefore , the communication was down 

[Mlex1]

Hi Sposter IT Services.

good explanation, wish you all the best