Lecture Notes 8 - Dynamic Routing Protocols I (RIP) PDF

LECTURE NOTE 8: Dynamic Routing Protocols I (RIP) 1. Introduction to RIP (Routing Information Protocol) RIP (Routing Information Protocol) is one of the oldest and simplest distance-vector dynamic routing protocols used in computer networks. It enables routers to automatically share routing informat...

LECTURE NOTE 8: Dynamic Routing Protocols I (RIP) 1. Introduction to RIP (Routing Information Protocol) RIP (Routing Information Protocol) is one of the oldest and simplest distance-vector dynamic routing protocols used in computer networks. It enables routers to automatically share routing information and update their routing tables, allowing dynamic discovery of routes across a network. Distance-Vector Protocol: RIP calculates the best path to a destination based on the hop count (the number of routers a packet must pass through to reach the destination). Hop Count Limit: RIP uses a maximum hop count of 15. If the hop count exceeds 15, the destination is considered unreachable. Version: RIP has two main versions: RIP v1: Classful routing (no support for subnetting or CIDR). RIP v2: Classless routing (supports subnetting and CIDR, and includes authentication). Updates: RIP routers send out routing updates every 30 seconds, sharing their routing tables with neighboring routers. Working Principle: ✓ Routers using RIP broadcast their entire routing table to their neighbors. ✓ Each router selects the path with the fewest hops to a destination network and updates its routing table accordingly. ✓ If a route becomes unreachable (e.g., a link failure), RIP removes it after 180 seconds of inactivity. 2. Configuring RIP ✓ Configuring RIP is straightforward. Step-by-Step RIP Configuration: ✓ Topology Overview: We have two routers: Router 1 and Router 2, each with its own local network. Router 1 Router 2 192.168.1.0/24 (connected to PC1) 192.168.2.0/24 (connected to PC2) 10.0.0.0/30 (connected to Router 2) 10.0.0.1/30 (connected to Router 1) ROUTER 1: ✓ Step 1: Access Router Configuration Mode ✓ Enter privileged EXEC mode: Router> enable  ✓ Enter global configuration mode: Router# configure terminal Step 2: Enable RIP ✓ Enter RIP routing configuration mode: Router(config)# router rip ✓ Specify RIP version 2 (recommended for modern networks): Router(config-router)# version 2 ✓ Step 3: Configure Networks for RIP ✓ Specify the network that the router is directly connected to (e.g., 192.168.1.0/24): Router(config-router)# network 192.168.1.0 ✓ Also, specify the network connecting to the other router (e.g., 10.0.0.0/30): Router(config-router)# network 10.0.0.0 ✓ Step 4: Exit RIP Configuration ✓ Exit RIP routing mode: Router(config-router)# exit ✓ Step 5: Save the Configuration ✓ Save the running configuration to the startup configuration: Router# write memory ROUTER 2: ✓ Step 6: Repeat on the Other Router ✓ Follow the same process to configure RIP on Router 2, ensuring the correct networks are added: ✓ network 192.168.2.0 ✓ network 10.0.0.0 ✓ Step 7: Verification ✓ Check the routing table on both routers to verify that RIP has learned routes: Router# show ip route ✓ Ping between devices on different networks (e.g., PC1 to PC2) to ensure connectivity. 3. Advantages and Limitations of RIP Advantages of RIP: Simplicity: ✓ Easy to configure, making it suitable for small networks. ✓ Requires minimal configuration commands compared to more advanced protocols like OSPF or EIGRP. Widely Supported: ✓ RIP is supported on almost all router brands and models due to its age and simplicity. Loop Avoidance (Split Horizon & Route Poisoning): ✓ RIP implements mechanisms like split horizon and route poisoning to avoid routing loops. Automatic Updates: ✓ RIP dynamically updates routing tables through periodic broadcasts, adjusting to network changes without manual intervention. Limitations of RIP: Scalability: ✓ RIP has a maximum hop count of 15, which makes it unsuitable for large networks or complex topologies with many routers. After 15 hops, a network is considered unreachable. Slow Convergence: ✓ RIP’s update interval is 30 seconds, and it can take up to 180 seconds to remove an unreachable route, making it slower to respond to network changes compared to other protocols. Bandwidth Usage: ✓ RIP sends the entire routing table in updates every 30 seconds, which can consume significant bandwidth in larger networks. No Support for VLSM in RIP v1: ✓ RIP v1 is classful, which means it doesn't support Variable Length Subnet Masking (VLSM) or Classless Inter-Domain Routing (CIDR). This limits IP address efficiency in modern networks. RIP v2 resolves this but is still less efficient than more advanced protocols.