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Choosing a routing protocol

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Choosing a routing protocol

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

Here's 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 the details of your situation, such as what your budget, equipment, and users are.

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

How many computers or devices are on your network?

The number of computers or devices that you have on your network, and whether the devices are all in one location or distributed, matters. All routing protocols can be run on networks of any size, but it can be inefficient to run some routing protocols on very small networks. Also, 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 applications 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 users have different expectations of the network. It's not critical for someone surfing the Internet to have 100% uptime, but it's 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 change 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, and others do not. If security is important to you, be aware of this.

What is your budget?

You need to know what both your initial and maintenance budget is. 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 and ongoing maintenance costs. If you ignore these costs, you risk having to drop the adoption of the new routing protocol mid-change.

Evaluate your chosen protocol

Once you've 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 installation of that protocol.

The test installation is generally set up in a sandbox configuration so it won't affect critical network traffic. The aim of the test installation is to prove that it will work on a larger scale on your network. You must ensure that the test installation mirrors your larger network well enough for you to discover any problems. If the test installation is too simpe, these problems may not appear.

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

Implement your dynamic routing protocol

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

This guide will help you configure a FortiGate 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 are included to show proper configurations for different types of networks.

Choosing a routing protocol

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

Here's 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 the details of your situation, such as what your budget, equipment, and users are.

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

How many computers or devices are on your network?

The number of computers or devices that you have on your network, and whether the devices are all in one location or distributed, matters. All routing protocols can be run on networks of any size, but it can be inefficient to run some routing protocols on very small networks. Also, 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 applications 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 users have different expectations of the network. It's not critical for someone surfing the Internet to have 100% uptime, but it's 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 change 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, and others do not. If security is important to you, be aware of this.

What is your budget?

You need to know what both your initial and maintenance budget is. 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 and ongoing maintenance costs. If you ignore these costs, you risk having to drop the adoption of the new routing protocol mid-change.

Evaluate your chosen protocol

Once you've 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 installation of that protocol.

The test installation is generally set up in a sandbox configuration so it won't affect critical network traffic. The aim of the test installation is to prove that it will work on a larger scale on your network. You must ensure that the test installation mirrors your larger network well enough for you to discover any problems. If the test installation is too simpe, these problems may not appear.

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

Implement your dynamic routing protocol

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

This guide will help you configure a FortiGate 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 are included to show proper configurations for different types of networks.