What are the principles of network topology



Computer networks are an extremely complex subject. That is why we only want to go into 2 common ways of realizing a network here. Larger networks such as the school network are almost always built according to the client-server principle. If there are very few networks, such as in small companies or at home, a peer-to-peer network may be sufficient. Both variants have their advantages and disadvantages, strengths and weaknesses.

Client-server architecture

The client-server architecture is an important construction principle of data processing systems and networks. Thereby, one or more central computers, the servers (dt. "Servants"), several workstations, the clients (dt. "Customers"), which can make use of the services offered by the servers. A server stores e.g. B. Databases (e.g. in a database), which different clients can access depending on their access authorization, or provides programs, memory, computing power, communication services (e.g. e-mail, fax), etc. A client computer is a working system even without the server (this is what distinguishes the client from a terminal on a mainframe). Its tasks are to provide the user with the best possible user interface and to take over all tasks that can be processed without a server (e.g. word processing, layout design).

A characteristic feature of the client-server architecture is the mutual autonomy of the components: Just as a client works without the server as part of its equipment, the server offers its services independently of the clients; the clients also have no influence on the processing of a request to the server as soon as the request has been sent.

The key advantage of the client-server architecture is that it enables resources to be distributed efficiently. Unlike a mainframe computer, a server is relieved of the simple tasks and tasks that only affect individual users (especially executing user programs); it is only used for extensive, complex or cross-computer activities (e.g. database administration, user administration, data storage in network drives. ..) responsible.

Conversely, the client stations can also be designed to be lean and only access the potential of a server when required. Their equipment is often limited to the needs tailored to the individual user, i.e. the usual office applications and communication software for exchange with the server. Because of this favorable distribution of work and resources, the data processing systems of many companies and many computer networks are now based on the client-server principle (client-server system, client-server network). The World Wide Web is an outstanding example of a client-server network. The various offers, services (e.g. e-mail), websites are stored on servers, so-called web servers; the computers of the individual users through which the web server is accessed represent the clients. Another architecture principle for networks is implemented in peer-to-peer networks. All connected workstations have the same priority, there is no server.

Peer-to-peer network

This is a network of peer computers. Each computer in the network can make its resources (e.g. hard disk, printer) available to the other computers and at the same time use their resources, i.e. act as a client and a server at the same time. This network architecture represents an alternative to the client-server architecture and, in the case of small networks consisting of a few computers, has the advantages that it can be implemented relatively inexpensively and is easy to handle. So you don't need an extra PC as a server, which can then no longer be used as a workstation, and the network programs are usually cheaper. Modern PC operating systems such as Windows NT / 2000 / XP offer the functionality to set up a P2P network, and operation can be managed without specialist knowledge.

In contrast, the more complex client-server networks require special network operating systems such as "Novell Netware" or "Windows 2000 Server" and precise knowledge of adjustments and technical problems. On the other hand, a P2P network does not allow such sophisticated user management and is - especially when the workload is high - not as efficient as a client-server network. P2P networks are particularly suitable for small work groups or companies, for example to enable data and message exchange as well as the shared use of output devices.