How to Configure OSPF Routing on a Cisco Router using Cisco Packet Tracer

Packet Tracer is a program developed by Cisco to configure computer networks in a “virtual” way. In this way, you can design a TCP/IP network in a virtual environment with this software before making sure it will work in the real scenario.

An OSPF network can be divided into smaller regions (areas). There is a special area called the backbone area that forms the central portion of the network to which the rest of the network is connected. The paths between different areas always circulate in the spine, so all areas must be connected to the spine. If a direct connection to the backbone cannot be established, a virtual connection can be made between networks.

Routers in the same multicast domain or at the end of a point-to-point connection form create connections when they discover each other. In the Ethernet network segment, the routers select a designated router (Dedicated Router, DR) and a designated secondary or replica router (Redundant Dedicated Router, BDR) that serve as hubs to reduce traffic between different routers.

OSPF can use both multicast and unicast to send welcome packets and link status updates. The multicast addresses used are 224.0.0.5 and 224.0.0.6. Unlike RIP or BGP, OSPF does not use TCP or UDP, instead, it encapsulates directly on the IP protocol by placing “89” in the protocol field.

OSPF regulates an autonomous system (AS) in areas. These fields are groups of logical routers whose information can be summarized for the rest of the network.

A domain is a routing unit, which means that all routers in the same domain hold the same topology map information in the Connection State Databases.

How to Enable OSPF on Cisco Router

In this article, we will enable the OSPF routing protocol on a Router with Cisco’s Packet Tracer software.

To setup the OSPF protocol:

Step 1: If you have not previously installed Packet Tracer on your computer, check the following articles to install on Windows, Linux, and macOS.

Step 2: After installation, open the simulator program and add two Cisco Routers to the workspace.

Step 3: Click on them to add Serial Interface to the Routers you have added and add the HWIC-2T module on the left side of the window.

Step 4: Add two Cisco Switches to the network topology and connect them to the routers.

Step 5: To make the connection between routers, select Serial cable from the cable types and click on them to connect the cable to the free ports.

Step 6: Add four PCs to the network topology and configure TCP/IP settings.

Step 7: Specify an IP block for the network between routers. Then, create two segments by specifying an IP block for the subnets of the Routers connected to the GigabitEthernet interfaces.

192.168.5.0/24
192.168.10.0/24

Step 8: After designing the IP of the network, run the following commands on R1 and R2 to activate OSPF Routing on the Router.

R1# conf t
R1(config)# router ospf 10
R1(config-router)# network 192.168.5.0 0.0.0.255 area 0
R1(config-router)# network 10.1.1.0 0.0.0.3 area 0
R1(config-router)# end

R2# conf t
R2(config)# router ospf 10
R2(config-router)# network 192.168.10.0 0.0.0.255 area 0
R2(config-router)# network 10.1.1.0 0.0.0.3 area 0
R2(config-router)# end

Step 9: After configuring OSPF Protocol on the Routers with the Cisco simulator software, test the network connection between all network devices.

   Related Articles

1. What is RIP
2. Cisco VLAN

 

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