Networks

Imagine you’ve bought the latest Google or Apple smartphone but are not allowed to connect it to your mobile phone network or Wifi. Despite their powerful hardware, phones are limited to being fairly expensive cameras and note-taking devices, unless you can connect them to other devices or systems to download apps, share pictures and videos, and chat with friends.

The device’s potential comes from the network.

_A network _is formed when 2 or more connected devices (computers, smart phones, smart home assistants etc) connect to each other to share data and resources.

A network can be as small as two devices connected together, like your smartphone and bluetooth headphones, through to networks with millions of nodes (a device connected to a network) connecting to each other through a series of interconnected networks, like the internet.

Bandwidth _is the amount of data that can be transmitted across a network. _Higher bandwidth means more data can be moved at faster speeds.

In the early days of the internet, it was common to connect using dial-up modems, which had very low bandwidth – you could spend an entire day trying to download one song, only to lose it partway through when someone went and picked up the phone. With the move to broadband (wide bandwidth = fast transfer speeds) connections, we can stream 4k videos to our devices almost instantly.

Wired Networks & Ethernet

We can split networks into wired and wireless.

Each device is connected by physical cables (the “wire” in wired) on a wired network. Smaller networks, like those in a home or office, are called LAN (Local Area Network).

These networks often use ethernet cables with RJ-45 connectors to physically connect the various devices. For longer distances (some network cables cross oceans), the cables are made using ultra-high bandwidth fibre optic cables that can transfer huge amounts of data at close to the speed of light.

Wired systems are capable of transferring data at very high speeds, but they do have one fairly obvious downside – devices need to be plugged in using a wire to connect to the network. This isn’t ideal for our modern portable devices (I doubt Apple would sell many watches if they had to be plugged into an ethernet cable!).

Thankfully, we also have _wireless _networks.

Wireless Networks & WiFi

I’m sure you’ve heard of Wi-Fi. Many people use the name to refer to any kind of wireless internet connection, but Wi-Fi is actually the name for a set of standards that work for wireless local area networks (WLAN) – basically, wireless networks across relatively short distances.

Modern Wi-Fi has fairly high bandwidth, so it’s often used in homes, offices, and universities to supply connections to laptops, smartphones, tablets, and smart TVs.

Because WiFi networks are local area networks, they are usually connected via a wired connection to the internet itself (so they are taking a wired internet connection and making it wireless within a small area).

WiFi networks usually operate independently of each other – if you’ve ever opened the “WiFi” settings on your phone or computer and seen a long list of available access points, you’ve probably already realised this. You can’t simply connect to the nearest WiFi access point automatically and then switch between all the other networks; you need to know the WiFi password to gain access to most networks.

Mobile networks

If the network needs to cover longer distances where Wi-Fi won’t work, we can turn to mobile networks, like we use for our smartphones.

While early mobile networks were painfully slow, modern networks use newer technologies like 4G (4th Generation broadband) or 5G (5th generation broadband) to offer very high transfer speeds to their customers. It’s becoming fairly common for people to have a 5G mobile connection with more bandwidth than the wired connection from their broadband provider at home.

Personal Area Networks

Finally, for really small networks – PAN or Personal Area Networks – we have standards like Bluetooth.

Bluetooth has been specially designed to operate at shorter distances, using much less power than Wi-Fi or mobile radio. This makes it a great choice for connecting personal devices together, like your wireless headphones with your phone, or your remote control and TV.

However, the limited bandwidth means Bluetooth isn’t a great choice when transferring larger amounts of data. This is why some portable devices, like DSLR cameras, will still turn to WiFi when they need to move large data, like 4k videos.