Client-server and peer-to-peer networks
Introduction
There are two many types of network that we should know about. The first one is known as a 'client-server' network. The second type is known as a 'peer-to-peer' network.
Client-server network
In a client server network, one computer has been set up to be a 'server' (often called a 'file server'). The server's main job is to keep the network secure. It does this by keeping a database of users who are allowed to login to the network and use it. Users who are authorised can login using a login and password. They can then use the software applications and hardware such as printers on the network. Some users may be given more 'rights' to use different things on the network than others. These are known as 'access rights'. On your school network, for example, you will be able to login and use quite a lot of the network but your teachers, when they login, will be able to access parts that you cannot get to or may be able to use a certain printer that you cannot print to. This is because they have different access rights. Servers usually have lots of hard disk space because they securely keep all of the authorised users' files on their hard disk rather than having the files stored locally on the 'clients'. They also have lots of RAM, because they have a lot of work to do and may need to have a lot of applications open at any one time.
The 'clients' on a client-server network are the individual computers that authorised users log into and use. They are like the customers of the server and an authorised user can usually login to any of the clients on the network and use them.
Peer-to-peer network
This type of network doesn't have a server. Instead, all of the computers on the network have equal status (they are peers of each other). Each one can communicate with all of the others and each of them may have a role in helping to manage the whole network. For example, one computer could send a file to another computer and have it saved on that computer. A computer might send a file to be printed to another computer, which has a printer attached to it.
These types of networks are quite simple and are fine for very small networks of about 10 computers or less. They aren't complicated to set-up but don't provide very many of the powerful features found in client-server networks. For example, client-server networks can provide sophisticated security from one point (the server) whereas security has to be set-up on individual computers on a peer-to-peer network (because they are all peers). You can back-up work easily on a central server but you have to back-up work on each computer in a peer-to-peer network.