Classifying Network By Architecture

Classifying networks by architecture, it means from where the clients are getting resources, whether they are getting resources from dedicated server or whether they are getting resources from one another.

Client Server Architecture:

In this architecture clients share resources made available by a server. Let's take an example of it:

In this case we have got a machine known as file server which is serving shared files that are used at that time on a project maybe or it is a database server but it is single repository that everybody points back to.
This file server must be running some sort of network operating system (NOS). NOS enables a computer to act as a server, maybe microsoft windows server, maybe MAC OS 10 server, maybe linux server. There are some operating systems that makes file server to serve. We can add users, we can give different users different level of permissions.
Suppose if client B want to access employee files then we will assign some password to client B then it will access those files while client A and C won't be able to access those files.
With network operating system (NOS) we can get users, we can get groups defined and assign different level of permissions to users and group of users to give them access or to block their access. This type of network is called client server network.