"Understanding Routing Protocols in Computer Networks"
- 2. CONTENTS Introduction of Routing Introduction of Router Types of Routing Comparison between Static and Dynamic Routing Protocols Types of Routing Protocols Difference between the Protocols
- 3. INTRODUCTION OF ROUTING Routing is a process that is performed by layer 3 (or network layer) devices in order to deliver the packet by choosing an optimal path from one network to another.
- 5. A Router is a networking device that forwards data packets between computer networks. One or more packed- switched networks or sub networks can be connected using a router. By sending data packets to their intended IP addresses, it manages traffic between different networks and permits several devices to share an Internet connection.
- 7. STATIC ROUTING Static Routing is also known as Nonadaptive Routing. It is a technique in which the administrator manually adds the routes in a routing table. A Router can send the packets for the destination along the route defined by the administrator. In this technique, routing decisions are not made based on the condition or topology of the networks
- 8. Advantages Of Static Routing No Overhead: It has ho overhead on the CPU usage of the router. Therefore, the cheaper router can be used to obtain static routing. Bandwidth: It has not bandwidth usage between the routers. Security: It provides security as the system administrator is allowed only to have control over the routing to a particular network.
- 9. DYNAMIC ROUTING It is also known as Adaptive Routing. It is a technique in which a router adds a new route in the routing table for each packet in response to the changes in the condition or topology of the network. Dynamic protocols are used to discover the new routes to reach the destination. In Dynamic Routing, RIP and OSPF are the protocols used to discover the new routes.
- 10. The Dynamic protocol should have the following features: • All the routers must have the same dynamic routing protocol in order to exchange the routes. • If the router discovers any change in the condition or topology, then router broadcast this information to all other routers. Advantages of Dynamic Routing: • It is easier to configure. • It is more effective in selecting the best route in response to the changes in the condition or topology. Disadvantages of Dynamic Routing: • It is more expensive in terms of CPU and bandwidth usage. • It is less secure as compared to default and static routing.
- 11. DEFAULT ROUTING It is also known as Adaptive Routing. It is a technique in which a router adds a new route in the routing table for each packet in response to the changes in the condition or topology of the network. Dynamic protocols are used to discover the new routes to reach the destination. In Dynamic Routing, RIP and OSPF are the protocols used to discover the new routes.
- 13. TYPES OF ROUTING PROTOCOLS
- 14. Distant vector protocol Distant vector protocol, also called as Bellman-Ford algorithm or Ford Fulkerson algorithm used to calculate a path. A distance- vector protoc ol calculates the distance and direction of the vector of the next hop from the information obtained by the neighboring router. It is necessary to keep track of the topology and inform neighboring devices if any changes occur in topology. The process of calculating the optima l path is done using the distant vector routing protocol.
- 15. Link-state routing Link-State Routing protocols build a complete topology of the entire network and then calculate the best path from the topology of all interconnected networks. In link-state routing, the distance is calculated based on multiple metrics from source to destination, one hop at a time. The link-state routing protocol maintains three different tables that are neighbor table, the topology table, and the routing table. The neighbor table stores the information of the neighbor table. The topology table stores the information on network topology, and the routing table keeps track of all the paths to the different networks. It requires more memory and processing power as it has the complete picture of the network.
- 16. PATH VECTOR PROTOCOL The path vector protocol is a routing protocol that keeps track of path information that is updated dynamically. The path vector protocol does not rely on the reachability to the destination, instead determines whether the path is loop-free or not. The path vector does the analysis of the path to determine whether the path is loop-free or not.
- 17. TYPES OF ROUTING PROTOCOLS Routing information protocol (RIP) ... Interior gateway protocol (IGRP) ... Enhanced interior gateway routing protocol (EIGRP) ... Open shortest path first (OSPF) ... Exterior Gateway Protocol (EGP) ... Border gateway protocol (BGP) ... Immediate system- to-immediate system (IS-IS)
- 18. ROUTING INFORMATION PROTOCOL(RIP) Routing Information Protocol (RIP) is a dynamic routing protocol that uses hop count as a routing metric to find the best path between the source and the destination network. It is a distance- vector routing protocol that has an AD value of 120 and works on the Network layer of the OSI model. RIP uses port number 520. Features of RIP : 1.Updates of the network are exchanged periodically. 2. Updates (routing information) are always broadcast. 3. Full routing tables are sent in updates. 4. Routers always trust routing information received from neighbor routers. This is also known as Routing on rumors.
- 19. Enhanced interior gateway routing protocol(EIGPR) Enhanced Interior Gateway Routing Protocol (EIGPR) is a dynamic routing protocol that is used to find the best path between any two- layer 3 devices to deliver the packet. EIGRP works on network layer Protocol of OSI model and uses protocol number 88. It uses metrics to find out the best path between two layer 3 devices (router or layer 3 switches) operating EIGRP.
- 20. Open shortest path first protocol(ospf) Open Shortest Path First (OSPF) is a link-state routing protocol that is used to find the best path between the source and the destination router using its own Shortest Path First). OSPF is developed by Internet Engineering Task Force (IETF) as one of the Interior Gateway Protocol (IGP), i.e, the protocol which aims at moving the packet within a large autonomous system or routing domain. It is a network layer protocol which works on protocol number 89 and uses AD value 110. OSPF uses multicast address 224.0.0.5 for normal communication and 224.0.0.6 for update to designated router(DR)/Backup Designated Router (BDR)
- 21. Border gateway protocol(bgp) The protocol can connect any internetwork of the autonomous system using an arbitrary topology. The only requirement is that each AS have at least one router that can run BGP and that is the router connected to at least one other AS’s BGP router. BGP’s main function is to exchange network reachability information with other BGP systems. Border Gateway Protocol constructs an autonomous systems graph based on the information exchanged between BGP routers.