Practical 9

AIM:

To configure routers using the OSPF (Open Shortest Path First) protocol to establish efficient routing in IP networks.

Introduction to OSPF:

Open Shortest Path First (OSPF) is a link-state routing protocol designed for IP networks, enabling routers to exchange link information and determine optimal paths for data packets based on a cost metric that considers bandwidth.

Advantages of OSPF:

Scalability: Supports large, complex networks through its hierarchical structure and multi-area support.
Efficiency: Uses a cost metric to select routes based on link performance, improving overall routing efficiency.
Robustness: Quickly adapts to network changes, minimizing downtime and maintaining stability.

Disadvantages of OSPF:

Complex Configuration: More challenging to set up than simpler protocols like RIP, requiring careful configuration.
Resource Intensive: Consumes more CPU and memory resources due to its detailed network state management.

Step-by-Step Configuration:

Step 1: Create the Network Topology

Open Cisco Packet Tracer and select the required network devices.
Arrange the devices to create the network topology.

Step 2: Configure PCs (Hosts) with IPv4 Addresses

Select each PC, go to Desktop > IP Configuration.
Assign an IPv4 address and Subnet Mask according to the IP addressing table.
Optionally, assign a Default Gateway for each PC.
To verify the IP configuration, use the command ipconfig or configure directly in the terminal:
```
ipconfig <IPv4 address> <Subnet mask> <Default gateway>
```

Step 3: Configure Router with IP Address and Subnet Mask

To assign IP addresses in Router0, click on Router0 and navigate to Config > Interfaces.
Ensure all relevant ports are enabled.
Assign IP addresses to the FastEthernet and Serial ports as per the IP addressing table.

Code: OSPF Configuration for Routers

Router 0 Configuration:


Router(config)# router ospf 1
Router(config-router)# network 192.168.1.0 0.0.0.255 area 0
Router(config-router)# network 10.0.0.0 0.255.255.255 area 0
Router(config-router)# network 12.0.0.0 0.255.255.255 area 0
Router(config-router)# exit

Router 1 Configuration:


Router(config)# router ospf 1
Router(config-router)# network 10.0.0.0 0.255.255.255 area 0
Router(config-router)# network 11.0.0.0 0.255.255.255 area 0
Router(config-router)# exit

Router 2 Configuration:


Router(config)# router ospf 1
Router(config-router)# network 192.168.2.0 0.0.0.255 area 0
Router(config-router)# network 11.0.0.0 0.255.255.255 area 0
Router(config-router)# network 12.0.0.0 0.255.255.255 area 0
Router(config-router)# exit

Step 4: Assign Routes to Routers

After configuring all devices, assign routes for each router.
For each router, access the CLI, then type the relevant network commands to assign routes:
```
network <network id>
```

Summary

This practical demonstrates the configuration of routers using OSPF, showcasing how routers can efficiently exchange link information and make optimal routing decisions across IP networks.