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Network Interface Controller (NIC)#

Computers on their own, in isolation, are still very useful devices. You can process large amounts of data to help you predict or understand some possible future event. You can render some very advanced 3D graphics or computer games. You can edit video, audio, and more.

But on their own, computers are limited. It's when we connect them together, via a network, that computers become expotentially more powerful. This is called "networking", and we have an entire chapter on it.

For a computer to connect to a network it needs a Network Interface Controller (NIC.) What we're going to briefly discuss below is a wired network controller, not a wireless one. Our laptop computers and mobile phones have NICs inside of them too, but instead of using a physical wire to connect you to the network, they use radio waves, hence being called "wireless".


Something you'll hear people referring to them as "network card" - that's just slang for "network controller". They're the same thing.

You're not going to deal with wireless technologies at all as a systems administrator. In the case of using Amazon Web Services, you won't even be dealing with the physical nature of a NIC. It's still important that you know about this small little piece of hardware because networking changed our society, our species, as a whole.

Here's what a NIC looks like:

Network Interface Controller

(afrank99, CC BY-SA 2.0, via Wikimedia Commons)

A NIC lets our computers join computer networks so we can access other remote systems. Without such technologies the Internet wouldn't exist.

Truth be told you don't really need to understand this technology all that much. The only reason I'm introducing you to the concept of a NIC is because you'll see them being referenced in Cloud and virtualised environments.

For example, in Amazon Web Services (AWS) you will deal directly with ENIs or "Elastic Network Interface". An ENI is a virtual network interface. It allows you to connect your servers in AWS to other networks, including the Internet.

So, what is a "Network Interface"? Well now you know: it's a piece of (potentially virtualised) hardware that lets a computer connect to and utilise a computer network, such as the local network or the Internet.

And that's it.

I highly recommend not thinking too much more about this topic at this point in time. There is little more knowledge to be gained and because the networking stack is so heavily abstracted away in Cloud and virtualised environments, you'll never interact with it at the hardware level.