In this chapter, we present a methodology which, when applied to the various phases of equipment and network development, should ensure that performance and quality of service (QoS) objectives are met. As in Chapter 2, we will stress the generic aspects of the approach, while drawing on concrete examples of existing networks and equipments.

In the preceding chapters, we presented an overview of performance parameters and the corresponding objectives which are generally required by standards or by suppliers of networks and services. We have also presented the tools necessary for calculating these parameters.

We will now show how these various elements can be applied as part of a methodology which is truly integrated with the development life cycle of products and networks. This methodology is aimed at guaranteeing to the equipment supplier that the targets will be met within the required time frames, to the network supplier that the equipments comply with the specifications, and finally to the user that the service provided will meet his/her expectations.

In practice, we will show here the various facets of the performance evaluation profession, focussing in particular on the necessity of a global and coherent approach, from the start of the project up to the experimentation and the operational phase.