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1. Protocols and layers

Protocols are a set of rules governing how to carry out a process. We discussed the various protocols involved in network communications in another section. Click here to read more about them.

It can be difficult, though, to imagine how all of these different protocols interact with one another. There are a number of tools used by developers and computer scientists, but the easiest is the idea of layers. A layer is a group of protocols that all serve a similar function. For example since UDP and TCP do the same kind of job in two different ways, they would be in the same layer.

Layers are not physical things inside a computer or network. They're just a way of categorising protocols, of making them easier to think about and work with.

In the following pages, we will discuss a layer model that is particularly important to network communications, called the Four Layer Model.