Open Shortest Path First (OSPF)

Open Shortest Path First (OSPF)

To configure OSPF routing protocol use the following command:

Syntax:

Router(config)#router ospf <process id>

Router(config-router)#network <network ID> <wildcard mask> area <area no>

Configurations of Routers are given below: 

ON DELHI:

DELHI#configure terminal

DELHI(config)#ip routing

DELHI(config)#router ospf 5

DELHI(config-router)#network 192.168.1.0 0.255.255.255 area 0

DELHI(config-router)#network 172.16.0.0 0.0.255.255 area 0

DELHI(config-router)#end


ON KOLKATA:

KOLKATA#configure terminal

KOLKATA(config)#ip routing

KOLKATA(config)#router ospf 5

KOLKATA(config-router)#network 10.0.0.0 0.0.0.255 area 0

KOLKATA(config-router)#network 172.16.0.0 0.0.255.255 area 0

KOLKATA(config-router)#network 172.17.0.0 0.0.255.255 area 0

KOLKATA(config-router)#Ctrl + z


ON MUMBAI:

MUMBAI#configure terminal

MUMBAI(config)#ip routing

MUMBAI(config)#router ospf 3

MUMBAI(config-router)#network 192.168.2.0 0.255.255.255 area 0

MUMBAI(config-router)#network 172.17.0.0 0.0.255.255 area 0

MUMBAI(config-router)#Ctrl + z

To verify, the following commands can be give on all Routers

Show commands: 

Router#show ip route 

Router#show ip ospf neighbor 

Router#show ip ospf database

Verify the output using following commands

To verify the IP Routing table use the following command

Syntax: 

Router#show ip route

Output:

KOLKATA#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

C    10.0.0.0/8 is directly connected, FastEthernet0/0

C    172.16.0.0/16 is directly connected, Serial0/0/1

C    172.17.0.0/16 is directly connected, Serial0/0/0

O    192.168.1.0/24 [110/65] via 172.16.0.1, 00:08:39, Serial0/0/1

O    192.168.2.0/24 [110/65] via 172.17.0.2, 00:04:28, Serial0/0/0

To verify the OSPF database table use the following command


Syntax:

Router#show ip ospf database

Output:

KOLKATA#sh ip ospf database 

            OSPF Router with ID (172.17.0.1) (Process ID 3)

                Router Link States (Area 0)

Link ID             ADV Router      Age         Seq#           Checksum      Link count

192.168.1.1      192.168.1.1     661        0x80000003    0x00cf69              3

172.17.0.1        172.17.0.1      410        0x80000005    0x003e7d              5

192.168.2.1      192.168.2.1     410        0x80000003    0x00191a              3

To verify the directly connected OSPF neighbors and DR/BDR of use the following command :Syntax:

Router#show ip ospf database

Output:

KOLKATA#sh ip ospf neighbor 

Neighbor ID     Pri   State           Dead Time   Address         Interface

192.168.2.1       0   FULL/  -        00:00:38    172.17.0.2      Serial0/0/0

192.168.1.1       0   FULL/  -        00:00:31    172.16.0.1      Serial0/0/1

Debug the OSPF protocol:

Router#debug ip ospf

Enable logging on Telnet:

Router#terminai monitor