Client/Server Model

 Client/Server Model

Ø  In client server systems, the client requests a resource and the server provides that resource.

Ø  A server may serve multiple clients at the same time while a client is in contact with only one server. Both the client and server usually communicate via a computer network and so they are a part of distributed systems.

Ø  The client server computing works with a system of request and response. The client sends a request to the server and the server responds with the desired information.

Ø  The client and server should follow a common communication protocol so they can easily interact with each other. All the communication protocols are available at the application layer.

Ø  A server can only accommodate a limited number of client requests at a time. So it uses a system based to priority to respond to the requests.

Ø  An example of a client server computing system is a web server. It returns the web pages to the clients that requested them.

Ø  Advantages of Client Server Computing

·         All the required data is concentrated in a single place i.e. the server. So it is easy to protect the data and provide authorisation and authentication.

·         The server need not be located physically close to the clients. Yet the data can be accessed efficiently.

·         It is easy to replace, upgrade or relocate the nodes in the client server model because all the nodes are independent and request data only from the server.

Ø  Disadvantages of Client Server Computing

·         If all the clients simultaneously request data from the server, it may get overloaded. This may lead to congestion in the network.

·         If the server fails for any reason, then none of the requests of the clients can be fulfilled. This leads of failure of the client server network.

·         The cost of setting and maintaining a client server model are quite high.