An introduction to web applications architecture

Figure 1 Simple client–server application

Description

A diagram explaining simple client-server application. At the centre, there is a cloud shape, with 2 arrows, both sides, coming in and out of the cloud. From the left-hand side, there is a box, with the text inside: client (browser). The two arrows then link the box to the cloud. The top arrow goes away from the box, into the cloud, and the arrow beneath points away from the cloud into the box. On the right-hand side of the cloud, this is similar with the same style of box but with the following text inside: server application (book catalogue, pricing and stock). The top arrows either side of the cloud are labelled book information requests and the bottom arrows are labelled book lists and descriptions. Below the cloud, there is a double-ended, dashed-line arrow that runs horizontally, labelled network. On the left, the arrow points towards a box with the text: user’s own machine, and on the right the arrow points towards a box labelled: company’s server machine.
Back to Session 1 Figure 1

Figure 2 Example of multi-tier architecture

Description

This is a diagram demonstrating an example of multi-tier architecture. From the left, there are three rounded boxes, placed vertically above one another. They all have the same text inside: client (browser). Below these, there is a rectangle, with text that reads client tier. There are three arrows coming from the right, pointing towards the three rounded boxes. From this, the line goes into one and comes from a cloud shape. Below the cloud, there is a rectangle with the text: internet. Pointing to the right, there is an arrow coming out of the cloud and pointing towards a rounded box, with the text inside: web server. There is a rectangular box below it, with the text: server tier. On the right side of the rounded box, there is a double ended arrow pointing to the current rounded box and another rounded box on the right. The rounded box on the right of this has the text: business logic and a rectangular box below it, with the text: middle tier. To the right of the rounded box there is a double ended arrow, going to another set of arrows which point towards two further rounded boxes. The first one, at the top, has the text: sales records database, and the second one, below it, has the text: stock level database. Below this is a rectangular box that has the text: data tier.
Back to Session 1 Figure 2