The Need For Routing Protocols

Routers within a network use routing protocols to talk with one another so that updates and changes to the network can be adapted to dynamically without any major involvement from the network administrator. A router in a network has a routing table so that it can keep track of where his fellow routers are. It is like his contact list or address book. If routing protocols didn’t exist we would have to configure static routes manually to each router in the network on every single router. This can be a lot of work if you have a lot of routers. If you only have static routes and one of your links goes down in the middle of your network there is no real way for the routers to update each other on the status of the broken link. YOU, the network administrator, will have to go into every single router on the network and remove the bad link and define an alternate route. Again, this can be a lot of work if you have a lot of routers in your network creating a lot of down time.

Using a routing protocol will solve this issue of having to do all this manual work every time there is a change in your network. In the rest of this article we are going to focus on RIPv1 and its predicesor RIPv2, but there are several other routing protocols that we will learn about later for the ICND2 Exam and the CCNA Exam. RIP is a great tool to learn about routing protocols because it is simple to understand and easy to configure. Other routing protocols like EIGRP, OSPF and IS-IS are more advanced than RIP, but build upon RIP’s core functionality. We focus on learning RIP first because it builds a solid foundation of Routing Protocol knowledge that will make learning more advanced routing protocols much easier. For the ICND1 Exam you will need to know everything about RIPv2 (and RIPv1), and have only basic understanding for EIGRP, OSPF, and IS-IS.

So, what is a routing protocol? Basically it is a language or format that routers use to communicate with each other, so that they can automatically learn about new routes and make new routing dicisions incase a link goes down somewhere in the network. Having this ability to automatically make decisions can help keep your network running smoothly even when problems arise (Smoothly will depend largely on if you have redundant links in your network or not).

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