WEB Versus Client-Sever systems

The World Wide Web is a special case of the client-server paradigm.Client-Server means one or more centralized server computers that serve data, resources, programs connected to server a number of client computers.Traditionally, this involves a powerful central server connected to remote client computers that are often "dumb" in that they do no actual computation and simply provide an interface to the server. You can think of a dumb terminal as a keyboard and monitor into the remote server.

Many UNIX servers that are connected to thin clients, which means that most applications run on the server, but the clients are capable of local data storage and other small computational tasks.The server does most of the heavy computations.Windows networks are typically just the other way round, with the "fat client" possessing basic Office applications and browsing, with separate servers used for major services requiring either the network (Web server, DNS, and so on) or massive storage requirements (database and file servers).

WEB is a special case of the Client-Server model using fat clients and operating on protocols like HTTP, HTML, XML, and Simple Object Access Protocol (SOAP)...Moreover it adds the interesting problem of "untrusted" users. Whereas traditional networks exist within the firewalled protection of a company's private network. In traditional Client-Server networks it is fairly clear what processing should take place on the client and on the server.Also both of client and the server normally exist within the walls of a corporate ...

But this is not the case with the World Wide Web....The Web is different because the clients exist outside the control of the central server and the network.Unlike a LAN Web has no boundaries to protect.All the clients have to be treated as untrusted which puts additional requirements on how computation is distributed across the client and the server.LANs can be designed to maximize performance. The more computation that can be "pushed" to the client the faster the central server can execute.Perhaps this is one reason why the fat client paradigm has won out over thin clients.The computational burden can be more distributed for speeding up the network for everyone.

But the Web is a different thing altogether... It is essentially a network of untrusted clients and any of those can be hostile.This means that every input that originates at a client must be carefully checked and all security operations must be performed on the server.