It’s easier to think of why we need, and how we use networks.
- You need to share a document with a coworker in another location.
- You need to video conference with your family while on a business trip
- You need to print on the printer on the other side of the building or the other side of the planet.
Do you see the pattern?
- You connect with your coworker to share the document
- You connect with your family to video conference
- You connect with the printer to well print your file
The network, this "thing", allowing the sum of these connections to communicate with each other.
When networks connect to other networks this is called internetworking.
Do you see it? The Inter(net)working
The Internet is the sum of a great number of networks from all over the world.
If you connect to the Internet, you're actually connecting to your internet service provider’s (ISP’s) network. This could be your telephone, cable, or satellite provider. They in turn connect to other networks.
So when you type in www.google.com in your browser your device is connecting to your home or other network. Which is connected to an ISP that is connected to a connection of networks until you finally arrive on the network connecting to Google.
So, in short, a network is collection paths interconnecting devices allowing them to communicate.
They can be connected together in a wide variety of ways. Wire cables, wireless, microwave, infrared, etc.
They can communicate over common protocols. A protocol is just an agreed upon way they will communicate. TCPIP, IPX/SPX, AppleTalk, etc. TCPIP is what most everything today runs on.
This was my attempt at simplifying, what a network is.