What is a Network Model?

To understand networking, let’s first look at human communication. People need a common language to talk to each other. Imagine someone who speaks only English trying to communicate with someone who speaks only Chinese.

Figure 1 – Communication Without a Shared Language

Without a shared language, communication is impossible. Networking devices face the same challenge: equipment from different vendors cannot talk together unless they follow a common model.

So, what is a network model?

A network model is a conceptual framework that explains how network communication is organized. It does not perform communication itself, but provides a common reference so devices from different vendors can be designed to work together.

The model defines the structure of communication, while protocols provide the actual rules that devices use to exchange data.

A protocol is a set of rules that defines how devices exchange data across a network. You can think of it as a language for computers. If two devices use different protocols, they can't understand each other. It’s just like two people who don’t share the same language.

There are many types of protocols, each with its own role. For example:

• Some handle IP addressing (like IP).

• Others manage data delivery (like TCP).

• Others handle file transfer (like FTP).

So how do we make all these protocols work together? That’s the role of the network model: it organizes them into layers. Each layer handles a specific part of communication. It uses certain protocols to complete its task.

In short:

• Protocols do the work.

• The model tells them where and how to work.

Imagine the 1980s: no iPhones, no fiber optics, no Instagram. The first laptops were just being invented.
In the early days of networking, big companies like IBM and DEC, as well as smaller makers, built their own unique models.

Figure 2 – Proprietary Communication in the 1980s

As you can see above, proprietary models are created for each manufacturer of network devices. These models are used to design their own communication languages.