In the simplest explanation, networking is just computers talking to each other. They do this by sending data packets using various protocols and transmission mediums such as ethernet cable or Wi-Fi connections. Computers must also know how to find other computers on the network. To put it briefly, every computer on the network needs a unique address so messages know where to go after they are sent.
Networks exist for many reasons including:
The types of networks you deal with on a daily basis include local area networks (LANs) and wide area networks (WANs).
Many people today have LANs in their schools, offices, and even their homes. LANs are especially good for sharing Internet access and commonly used files and databases.
Users can also connect to wide area networks ( WANS ) as well, which are just large LANS spread out over several physical locations. The Internet itself is basically a large WAN, with each node on the network having it's own unique IP address.
As you may have read in books or seen in movies, security considerations play a large role when designing networks. Technology such as firewalls can both block and filter unwanted network traffic. Virtual private networks (VPNs) are used to connect remote users to office networks without jeopardizing security. VPNs use strong data encryption to hide data as it is moving between routers over the Internet.
Networking is not something you can master in a week or even a month. Hundreds of books have been written about the subject and many more hundreds will come in the future as technologies mature and evolve. If you work on networks for a living, you are called a network engineer, and you will probably take certification exams by networking companies such as Cisco.
There are other kinds of networking as well which are not always between PCs and servers. An example is Bluetooth technology, which is optimized for networking between common consumer electronics such as mobile phones, mp3 players, and similar devices.
Okay that's it for now! This is just a basic introduction to networking. You will find a lot more networking vocabulary to master in other units of English 4 IT, and many more on the way.