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> Chapter 20 - Networking > Dynamic Routing Overview > Choosing a routing protocol

Choosing a routing protocol

One of that hardest decisions in routing can be choosing which routing protocol to use on your network. It can be easy to decide when static routing will not meet your needs, but how can you tell which dynamic routing protocol is best for your network and situation?

Here is a brief look at the routing protocols including their strongest and weakest points. The steps to choosing your routing protocol are:

  1. Answer questions about your network
  2. Evaluate your chosen protocol
  3. Implement your dynamic routing protocol

Answer questions about your network

Before you can decide what is best for your situation, you need to examine what the details of your situation are such as what you have for budget, equipment, and users.

The following questions will help you form a clear idea of your routing needs:

How many computers or devices are on your network?

It matters if you only have a few computers, or if you have many and if they are all at one location or not as well. All routing protocols can be run on any sized network, however it can be inefficient to run some on very small networks. However, routers and network hardware that support dynamic routing can be more expensive than more generic routers for static routing.

What applications typically run over the network?

Finding out what application your users are running will help you determine their needs and the needs of the network regarding bandwidth, quality of service, and other such issues.

What level of service do the users expect from the network?

Different network users have different expectations of the network. Its not critical for someone surfing the Internet to have 100% uptime, but it is required for a stock exchange network or a hospital.

Is there network expansion in your near future?

You may have a small network now, but if it will be growing quickly, you should plan for the expected size so you don’t have to chance technologies again down the road.

What routing protocols do your networks connect to?

This is most often how routing protocol decisions are made. You need to be able to communicate easily with your service provider and neighbors, so often people simply use what everyone else is using.

Is security a major concern?

Some routing protocols have levels of authentication and other security features built in. Others do not. If security is important to you, be aware of this.

What is your budget — both initial and maintenance?

More robust and feature laden routing protocols generally mean more resources are required to keep them working well. Also more secure configurations require still more resources. This includes both set up costs, as well as ongoing maintenance costs. Ignore these costs at the risk of having to drop the adoption of the new routing protocol mid-change.

Evaluate your chosen protocol

Once you have examined the features of the routing protocols listed above and chosen the one that best meets your needs, you can set up an evaluation or test install of that protocol.

The test install is generally set up in a sandbox configuration so it will not affect critical network traffic. The aim of the test install is to prove that it will work on a larger scale on your network. So be sure that the test install mirrors your larger network well enough for you to discover any problems. If its too simplistic, these problems may not appear.

If your chosen protocol does not meet your goals choose a different protocol and repeat the evaluation process until either a protocol meets your needs, or you change your criteria.

Implement your dynamic routing protocol

You have examined your needs, selected the best matching dynamic routing protocol, tested it, and now you are ready to implement it with confidence.

This guide will help you configure your FortiGate unit to support your chosen dynamic routing protocol. Refer to the various sections in this guide as needed during your implementation to help ensure a smooth transition. Examples for each protocol have been included to show proper configurations for different types of networks.