First in a series of articles on the analysis and improvement of application performance on the WAN

Overview

Although end users often complain about the performance of applications, especially web based applications, it is often difficult to quantify what counts as unsatisfactory performance. For that reason, it is good practice is to develop some sort of framework specifically for the performance optimisation of applications delivered over the wide area network or, indeed, across the Internet so that you, as the technical resource, might be able to identify the root cause and devise a strategy to improve the end user’s perception. This might involve the deployment and configuration of some very expensive network devices, the profiling of database queries, the identification of shoddily written code or a nice new state of the art laptop for all concerned. Beware, however, that you will be dealing with perception here and there may be non-technical reasons behind any complaint.

The Scenarios

As a first step though, a few simple scenarios will need to be analysed in order to develop an understanding of the most effective means of achieving a performance improvement in the network shown below (Figure 1). Note that the objects shown in the diagram below represent abstract devices rather than any particular manufacturer’s product but it is safe for you to assume that these abstract devices have similar capabilities to those of the real devices. . As in the real world, it will be safe to assume that merely adding a device like a WAN accelerator or a load balancer in its default configuration will not achieve the kind of application performance improvement that an end user might notice. Remember that detail is everything in the development of an application profile with the focus being firmly on generating an understanding of how things work all the way from client to front end server.

The Network Diagram

Device Capabilities