OSPF-Dynamic-Routing

OSPF (Open Shortest Path First) is a link-state dynamic routing protocol that uses the Dijkstra algorithm to calculate the shortest path. It provides fast convergence, scalability, and efficient routing updates, making it ideal for medium to large networks.

Topology Description:-

Routers: 3 (connected in a triangular fashion with serial/fast Ethernet links). Switches: 3 (one per router). End Devices: 6 Laptops (2 per LAN). IP Addressing Scheme:- LAN1 (Left) → 192.168.0.0/28 LAN2 (Middle) → 192.168.0.16/28 LAN3 (Right) → 192.168.0.32/28 Router-to-Router Links → 100.0.0.0/30 and 200.0.0.0/30

Step-by-Step Procedure:-

Step 1: Assign IP Addresses;

1.Configure IP addresses on all router interfaces (LAN & WAN). 2.Assign static IPs to all laptops in the respective subnets. 3.Verify connectivity within the same LAN using ping.

Step 2: Configure OSPF on Routers:-

On each router, enter OSPF configuration mode and enable OSPF for all directly connected networks.

Router(config)# router ospf 1 Router(config-router)# network 192.168.0.0 0.0.0.15 area 0 Router(config-router)# network 100.0.0.0 0.0.0.3 area 0 Router(config-router)# network 200.0.0.0 0.0.0.3 area 0 (Repeat similar commands on other routers, adjusting network IDs and wildcard masks as per IP plan.)

Step 3: Verify OSPF Neighbors:-

Use the following command to ensure routers have discovered each other; Router# show ip ospf neighbo

Step 4: Verify Routing Table:-

Check if OSPF routes are learned dynamically; Router# show ip route

Step 5: Test End-to-End Connectivity:-

Ping from a laptop in LAN1 to laptops in LAN2 and LAN3. All devices should successfully communicate across different subnets.

Key Learnings:-

1. How to configure OSPF routing on multiple routers.
2. Understanding wildcard masks in OSPF configuration.
3. Verifying neighbor relationships and routing tables.
4. Ensuring end-to-end communication across different LANs.
5. Observing how OSPF adapts to network changes.