How the Web Server Works

In the first chapter we introduced the notion of a web server – a piece of software running on a computer that distributes web pages to users on demand, and provides an area in which to store and organize the pages of a web site. The machine that runs the web server software could be a remote machine sitting at the other side of your network, or even on the other side of the world, or it could be your very own home machine. We also introduced the idea that the user's browser was the client in this relationship, and we saw how ASP fits into this 'client–server' relationship.

These days, the term client–server is probably overused; but in fact, when used to describe the workings of the web, it's almost perfect. In a nutshell, the client–server relationship describes the distribution of tasks between a server (which stores, processes and distributes data, like an ATM or cashpoint machine) and the clients that access the server (like customers queuing to get their money out), in order to achieve universal access for the network on which they are connected.

The client–server scenario is also commonly known as a two-tier system. More generally, application architecture has talked in terms of n-tier systems, where n refers to the number of layers in the system. In the client–server scenario, there are two layers. In Chapter 12 , we'll introduce a third layer – the database layer – and we'll start to think in terms of three-tier examples. But for now, let us expand on the two-tier or client–server system, as it relates to web pages.