OSPF Configuration Problem

[wasiimcisco]

Hi,

I am trying to configure OSPF between Four Router

R1---------) R2---------------) R3---------------) R4

R2 and R3 is ABR.

Area 1 is between R1 and R2

Area 10 is between R3 and R4

Area 0 is between R2 and R3

===============================================================================================

R1

interface FastEthernet0/0

ip address 192.168.30.9 255.255.255.248

des connected to R2

duplex auto

speed auto

end

router ospf 10

log-adjacency-changes

network 0.0.0.0 255.255.255.255 area 1

*Apr  7 10:38:37.947: %OSPF-4-ERRRCV: Received invalid packet: mismatch area ID, from backbone area must be virtual-link but not found from 192.168.20.1, FastEthernet0/0

===========================================================================================

R2

nterface FastEthernet0/1

ip address 192.168.20.1 255.255.255.252

des connected to R3

duplex auto

speed auto

end

interface FastEthernet0/0

ip address 192.168.30.10 255.255.255.248

des connected to R1

duplex auto

speed auto

end

router ospf 20

log-adjacency-changes

network 192.168.20.0 0.0.0.255 area 0

network 192.168.30.0 0.0.0.255 area 1

R2(config-router)#do show ip os int brief

Interface    PID   Area            IP Address/Mask    Cost  State Nbrs F/C

Fa0/1        20    0               192.168.20.1/30    1     DR    0/0

Fa0/0        20    1               192.168.30.10/29   1     BDR   1/1

*Sep 15 22:42:31.787: %OSPF-4-ERRRCV: Received invalid packet: mismatch area ID, from backbone area must be virtual-link but not found from 192.168.20.1, FastEthernet0/0

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

R3

interface FastEthernet0/0

ip address 192.168.20.2 255.255.255.252

des connected to R2

duplex auto

speed auto

interface FastEthernet0/1/0

ip address 192.168.10.1 255.255.255.224

des connected to R4

duplex auto

speed auto

router ospf 30

log-adjacency-changes

network 192.168.10.0 0.0.0.31 area 10

network 192.168.20.0 0.0.0.0 area 0

Sep 15 22:29:18.813: %OSPF-4-ERRRCV: Received invalid packet: mismatch area ID, from backbone area must be virtual-link but not found from 192.168.20.1, FastEthernet0/1/0

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

R4

interface FastEthernet0/1

ip address 192.168.10.2 255.255.255.224

duplex auto

speed auto

end

interface FastEthernet0/0

ip address 192.168.10.33 255.255.255.240

duplex auto

speed auto

end

router ospf 40

log-adjacency-changes

network 192.168.10.33 0.0.0.0 area 10

network 192.168.10.0 0.0.0.255 area 10

R4# show ip os int brief

Interface    PID   Area            IP Address/Mask    Cost  State Nbrs F/C

Fa0/1        40    10              192.168.10.2/27    1     DR    1/1

Fa0/0        40    10              192.168.10.33/28   1     DR    0/0

ep 15 22:37:20.685: %OSPF-4-ERRRCV: Received invalid packet: mismatch area ID, from backbone area must be virtual-link but not found from 192.168.20.1, FastEthernet0/1

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

Please let me know how to avoid this OSPF error. Where i am doing the misake.

This is a lab setup in which all the four routers are connected in layer 2 in the same VLAN.

Thanks in Advance.

[Jon Marshall]

Are you saying all the interfaces are in the same L2 vlan ?

If so you need to use a vlan per IP subnet and not have all interfaces in the same vlan.

OSPF on ethernet networks will be using DR/BDR and sending updates using 224.0.0.5 & 224.0.0.6 multicast messages. These messages will flood within the same vlan so that is why you are getting all these messages.

Jon

[wasiimcisco]

Hi,

thanks for the reply, if this is because of DR/BDR. I have tried by making all the interface point-to-point

ip os network point-to-point

but still i am getting the same error.

Interface    PID   Area            IP Address/Mask    Cost  State Nbrs F/C

Fa0/1        40    10              192.168.10.2/27    1     P2P   1/1

Fa0/0        40    10              192.168.10.33/28   1     P2P   0/0

Please guide me why after p-2-p network still this is happening.

[Jon Marshall · Accepted solution]

Even with point to point on ethernet multicast is still used - this time just 224.0.0.5

Unless you are doing this just to experiment then this is not the way to setup OSPF. Each IP subnet should be in it's own vlan. Because you have them all in the same L2 vlan the multicast updates are seen by each router and that is why you are getting all the error messages.

Jon

[wasiimcisco]

Hi,

Thanks for the reply, Actually this is a lab in book (Routing TCP/IP Vol 2) Configuration of OSPF page 412.

[wasiimcisco]

Hi,

I am able to configure OSPF and no error mesage is coming after creating the VLAN.

But now one more problem is coming I have created 5 loopbacks in Router A and I am advertising the summary route but the neighboring routers are not able to see the summary route.

interface Loopback0

ip address 10.0.0.1 255.255.0.0

!

interface Loopback1

ip address 10.1.0.1 255.255.0.0

!

interface Loopback2

ip address 10.2.0.1 255.255.0.0

!

interface Loopback3

ip address 10.3.0.1 255.255.0.0

!

interface Loopback4

ip address 10.4.0.1 255.255.0.0

!

interface Loopback5

ip address 10.5.0.1 255.255.0.0

!

interface Loopback6

ip address 10.6.0.1 255.255.0.0

!

interface Loopback7

ip address 10.7.0.1 255.255.0.0

router ospf 1

log-adjacency-changes

no discard-route

area 15 range 10.0.0.0 255.248.0.0

network 10.8.1.0 0.0.0.255 area 0

network 172.17.1.0 0.0.0.255 area 15

show 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

     172.17.0.0/16 is variably subnetted, 2 subnets, 2 masks
C       172.17.1.0/24 is directly connected, FastEthernet0/1
O       172.17.0.1/32 [110/2] via 172.17.1.2, 00:03:33, FastEthernet0/1
     172.16.0.0/32 is subnetted, 2 subnets
O IA    172.16.27.195 [110/3] via 10.8.1.1, 00:13:12, FastEthernet0/0
O IA    172.16.27.1 [110/3] via 10.8.1.1, 00:13:12, FastEthernet0/0
     172.20.0.0/30 is subnetted, 2 subnets
O IA    172.20.1.0 [110/2] via 10.8.1.1, 00:13:12, FastEthernet0/0
O IA    172.20.1.4 [110/2] via 10.8.1.1, 00:13:12, FastEthernet0/0
     10.0.0.0/8 is variably subnetted, 10 subnets, 3 masks
C       10.8.1.0/24 is directly connected, FastEthernet0/0
C       10.2.0.0/16 is directly connected, Loopback2
C       10.3.0.0/16 is directly connected, Loopback3
C       10.0.0.0/16 is directly connected, Loopback0
S       10.0.0.0/13 is directly connected, Null0
C       10.1.0.0/16 is directly connected, Loopback1
C       10.6.0.0/16 is directly connected, Loopback6
C       10.7.0.0/16 is directly connected, Loopback7
C       10.4.0.0/16 is directly connected, Loopback4
C       10.5.0.0/16 is directly connected, Loopback5

interface Loopback0

ip address 10.0.0.1 255.255.0.0

!

interface Loopback1

ip address 10.1.0.1 255.255.0.0

!

interface Loopback2

ip address 10.2.0.1 255.255.0.0

!

interface Loopback3

ip address 10.3.0.1 255.255.0.0

!

interface Loopback4

ip address 10.4.0.1 255.255.0.0

!

interface Loopback5

ip address 10.5.0.1 255.255.0.0

!

interface Loopback6

ip address 10.6.0.1 255.255.0.0

!

interface Loopback7

ip address 10.7.0.1 255.255.0.0

router ospf 1
log-adjacency-changes
no discard-route
area 15 range 10.0.0.0 255.248.0.0
network 10.8.1.0 0.0.0.255 area 0
network 172.17.1.0 0.0.0.255 area 15

ip route 10.0.0.0 255.248.0.0 Null0

I have created the null 0 route as well but no luck.

#show 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

     172.17.0.0/16 is variably subnetted, 2 subnets, 2 masks
C       172.17.1.0/24 is directly connected, FastEthernet0/1
O       172.17.0.1/32 [110/2] via 172.17.1.2, 00:03:33, FastEthernet0/1
     172.16.0.0/32 is subnetted, 2 subnets
O IA    172.16.27.195 [110/3] via 10.8.1.1, 00:13:12, FastEthernet0/0
O IA    172.16.27.1 [110/3] via 10.8.1.1, 00:13:12, FastEthernet0/0
     172.20.0.0/30 is subnetted, 2 subnets
O IA    172.20.1.0 [110/2] via 10.8.1.1, 00:13:12, FastEthernet0/0
O IA    172.20.1.4 [110/2] via 10.8.1.1, 00:13:12, FastEthernet0/0
     10.0.0.0/8 is variably subnetted, 10 subnets, 3 masks
C       10.8.1.0/24 is directly connected, FastEthernet0/0
C       10.2.0.0/16 is directly connected, Loopback2
C       10.3.0.0/16 is directly connected, Loopback3
C       10.0.0.0/16 is directly connected, Loopback0
S       10.0.0.0/13 is directly connected, Null0
C       10.1.0.0/16 is directly connected, Loopback1
C       10.6.0.0/16 is directly connected, Loopback6
C       10.7.0.0/16 is directly connected, Loopback7
C       10.4.0.0/16 is directly connected, Loopback4
C       10.5.0.0/16 is directly connected, Loopback5

Topology is mention in page 435 Routing TCP/IP Routing Vol 1

Please assist me.

[Reza Sharifi]

Hi,

In your config below, you have deployed the area range command, but have not not actually advertised the Loopback addresses of the interfaces 0 through 7 using the network command.

router ospf 1

log-adjacency-changes

no discard-route

area 15 range 10.0.0.0 255.248.0.0

network 10.8.1.0 0.0.0.255 area 0

network 172.17.1.0 0.0.0.255 area 15

If you go to router B and do a "sh ip route" do you see for example 10.3.0.0 ?

HTH

[wasiimcisco]

Hi,

NO I am not able to see any loopback route on Router B.

B#show 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

     172.17.0.0/16 is variably subnetted, 2 subnets, 2 masks
O IA    172.17.1.0/24 [110/2] via 10.8.1.2, 10:04:06, FastEthernet0/1/0
O IA    172.17.0.1/32 [110/3] via 10.8.1.2, 10:04:06, FastEthernet0/1/0
     172.16.0.0/32 is subnetted, 2 subnets
O       172.16.27.195 [110/2] via 172.20.1.6, 10:04:06, FastEthernet0/1
O       172.16.27.1 [110/2] via 172.20.1.2, 10:04:06, FastEthernet0/0
     172.20.0.0/30 is subnetted, 2 subnets
C       172.20.1.0 is directly connected, FastEthernet0/0
C       172.20.1.4 is directly connected, FastEthernet0/1
     10.0.0.0/24 is subnetted, 1 subnets
C       10.8.1.0 is directly connected, FastEthernet0/1/0
     192.168.50.0/32 is subnetted, 1 subnets
C       192.168.50.4 is directly connected, Loopback0

Actually I am following the steps mention in the Routing TCP/IIP Vol book that is why I didnt advertise loopback into OSPF.

I have a doubt. Do I need to advertise every network in the OSPF of Router A. Only summary advertise will not be enough. If i will advertise individual loopback then Router B will have the summary as well as specific route as well and always prefer the specific not the summary then what wil be use of Summary Route.

Please assist