Using a Network Simulator (e.g. packet tracer) configure

d. OSPF
The Open Shortest Path First (OSPF) is a routing protocol for wide area networks and enterprise network. OSPF is perhaps the most widely used interior gateway protocol (IGP) in large enterprise networks. The IS-IS, is another link-state dynamic routing protocol, which is more common in large service provider networks. The most widely used exterior gateway protocol is the Border Gateway Protocol (BGP), the principal routing protocol between autonomous systems on the Internet.

This video will help you to configure OSPF Protocol

Basic Router Commands

Router 1: Do the basic configuration of your routers, switches and computers. Set the IP address for each interfaces the same as screenshot. The diagram is classless IP addresses and sub-netted to many networks. So it means you must familiar with IP sub-netting and VLSM.

R1>enable
R1#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#interface serial 1/3
R1(config-if)#ip address 20.10.10.1 255.255.255.252
R1(config-if)#no shutdown
R1(config-if)#exit
R1(config)#
R1(config)#interface serial 1/1
R1(config-if)#ip address 10.10.10.1 255.255.255.252
R1(config-if)#clock rate 64000
R1(config-if)#no shutdown
R1(config-if)#exit
R1(config)#
R1(config)#interface serial 1/0
R1(config-if)#ip address 10.10.10.5 255.255.255.252
R1(config-if)#clock rate 64000
R1(config-if)#no shutdown

Router 2:
Do the following configuration for Router 2.

R2(config)#interface serial 1/0
R2(config-if)#ip address 10.10.10.6 255.255.255.252
R2(config-if)#no shutdown
R2(config-if)#exit
R2(config)#interface fastEthernet 0/0
R2(config-if)#ip address 192.168.10.1 255.255.255.0
R2(config-if)#no shutdown

Router 3:
Now try to set IP address for Router 3 interfaces also.

Router#enable
Router#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#hostname R3
R3(config)#interface serial 1/0
R3(config-if)#ip address 10.10.10.2 255.255.255.252
R3(config-if)#no shutdown
R3(config-if)#exit
R3(config)#interface fastEthernet 0/0
R3(config-if)#ip address 192.168.1.1 255.255.255.0
R3(config-if)#no shutdown

Good, the basic configuration has competed and now start configure OSPF routing protocol on this network.
How to Configure OSPF Routing Protocol?

The Lab is ready for routing, download and configure OSPF routing with the following step by step guide. In the router R1 configure OSFP routing with Router ospfcommand.

R1>enable
R1#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#router ospf 1
R1(config-router)#network 20.10.10.0 0.0.0.3 area 0
R1(config-router)#network 10.10.10.0 0.0.0.3 area 0
R1(config-router)#network 10.10.10.4 0.0.0.3 area 0
R1(config-router)#

The router OSPF command is enable OSPF routing on the router, and the 1 beforeOSFP is the process ID of the OSFP Protocol. You can set different process id from “1-65535” for each router.

The network command with network ID “network 20.10.10.0” is the network identifier, and the “ 0.0.0.3″ is the wildcard mask of 20.10.10.0 network. Wildcard mask determine which interfaces to advertise, because OSPF advertise interfaces, not networks.

Now go to Router R3 and configure with the following commands.

R3>enable
R3#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
R3(config)#router ospf 1
R3(config-router)#network 192.168.1.0 0.0.0.255 area 0
R3(config-router)#network 10.10.10.0 0.0.0.3 area 0

Done? So do the following for router R2.

R2>enable
R2#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
R2(config)#router ospf 1
R2(config-router)#network 192.168.10.0 0.0.0.255 area 0
R2(config-router)#network 10.10.10.4 0.0.0.3 area 0

OK, OSPF routing configuration has been finished successfully, now test your network whether they can ping with each other or not.