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Introduction to Networking

Introduction

Welcome to the first part of the Network Fundamentals study notes! If you haven’t already, we recommend watching the video first.

We’re going to start with understanding what a network actually is, and some of the types of networks you’ll see. We’ll also look at how a network may be cabled, and get an overview of addresses.

What is a Network

You may already know what a network is. Maybe you have built your own network at home or helped someone run the network at school or at your job.

At work or home, you have a bunch of devices; Computers, printers, TVs, and so on. You connect these by means of a network.

When the devices are connected, they’re able to share information. This could be sending a print job to a printer, sending an email, or streaming video. This can also be used for sharing an internet connection

For all these devices to communicate, they need to be connected together somehow. One way is to plug cables into the devices and connect them to another device called a switch.

An example is in a school’s computer lab. In this case, a computer in the lab connects to a wall socket with a cable.

Another cable runs through the wall, and comes out at a ‘patch panel’. This may be in a cabinet on the wall somewhere in the room, or in another room entirely.

The port on the patch panel then connects to a switch.

You might have a switch at home too. Most homes don’t have wall sockets, so devices are connected directly to the switch. We’ll talk more about how switches work in a future video.

We can also connect devices wirelessly. A common way to do this is to use a Wireless Access Point. A wireless network like this is also called ‘WiFi’.

An example of this is if you have a smartphone. It’s impractical to cable it in, so wireless is a good option.

The Access Point is like a switch without cables. More than one device can connect to the access point at a time but without the messy cabling.

The access point can also be connected to the switch with a cable. This way, wired and wireless devices can all be part of the same network.

Having both wired switches and wireless access points gives you more connection options.

Imagine you have a laptop in an office. You may connect it to the network with a cable when you’re at your desk.

When you have a meeting in the conference room, you remove the cable and connect to WiFi.

Whether wired or wireless, the goal of the network is to move information from one device to another.

For this to work, the sender and the receiver must understand each other. They need to speak the same language.

In the network, speaking the same language means that devices agree on how data is sent, received, organized, and handled. Basically, they agree on a process that they all follow. It’s a bit like paperwork.

This is called a protocol. A lot of different protocols are used, depending on what’s needed at the time.

Network software and hardware are designed with these protocols in mind.

You will hear of protocols like Ethernet and TCP, which are used for sending and receiving data. You may also hear of protocols like HTTP, which is used for accessing the web, and SMTP, which is used for email.

Usually, several protocols are used together to achieve a task. We’ll look at protocols further in future videos.

Network Types

Networks connect devices. You could call devices on the network ‘nodes’.

Nodes may include devices that help control the traffic flowing through a network, like switches and routers.

Nodes also include ‘endpoints’ or ‘hosts’. These are devices that send and receive the bulk of the traffic. This includes workstations, servers, printers, and so on.

Networks come in different sizes. A network at home is an example of a small network. These networks usually only have a few nodes.

This is called a ‘SOHO’ network. SOHO means ‘Small Office, Home Office’.

These networks typically have a couple of computers, a printer, a few phones and tablets. Some devices will be wireless, and some are connected to a switch.

People often say ‘hub’ when they mean ‘switch’. Switches and hubs are different things. Hubs are really old technology, while switches (which replaced hubs) are modern and commonly used.

In a SOHO network, a router is used to connect to the internet. You might find that the router, switch, and access point are all integrated into one device.

While a SOHO network will only have a few devices, a corporation (for example, a bank) will have many devices. This is called an enterprise network.

The enterprise network may cover several floors in a building. They may also have several office buildings in different cities or even across different countries.

An internet provider has a very large network. This is called a ‘Service Provider network’.

Not only do they provide internet access, they also offer services to connect their customers together.

Consider the bank with offices around the country. The service provider uses part of its network to join these offices together.

When devices are collected into a small area, we call this a Local Area Network, or LAN.

The LAN may be a small network. In a SOHO network, the LAN is the switch with the handful of devices connected.

Or, the LAN may be part of a bigger network, like an enterprise network. This network may have many switches, routers, and access points, depending on their needs.

Think of the bank from before. They have an office with several floors. You could consider the whole building as the LAN.

Or, more likely, the network is broken up into smaller parts. Perhaps there is a separate network on each floor. Each of these could also be called a LAN.

These separate LANs may also be connected together, but we’ll talk more about that later.

But a bank’s network is going to be larger than just one building. Banks have offices all over the country, and all over the world.

Even though they are far apart, these networks can be joined together. This is called a WAN, or Wide Area Network.

Imagine that you work for a company with an office in Sydney, and an office in Melbourne. You could contact a service provider, and they can connect the offices for you.

WANs are a topic all of their own, so we’ll cover them in a later video.