, hier- archical approach to SLM. One such is ServiceAssure from Comnitel Technologies. The inheritance approach enables the operator to implement service manage- ment in a structured way and to deliver some real benefits to their business quickly. A fully top-down approach to defining SLA may be time consuming, and in early implementations can appear daunting. On the other hand, the definition of generic services tends to be quicker, easier to understand and easier to implement. 7.6 Example: Key Quality Indicators for Wireless Services Measurement Service Providers have historically reported the performance of their networks against a set of business agreed key performance indicators (KPIs). These KPIs are, 4 Implementing Service Level Management Customer SLAs Product Additional Internal & S/P SLAs Product Components Service Additional Service Elements Additional Service Resources Figure 7.8 Hierarchy of key indicators. by their nature, network focused and provide little direct indication of the end-to-end service delivery that the network supports. Nevertheless, KPIs are an important measurement for network operations and will continue to be so for the foreseeable future as they indicate performance of individual service components. KPIs are usually derived from a number of data sources, and not just limited to network per- formance statistical data. For example, network fault data are also often used in cal- culating availability KPIs. The move towards service-focused management leads to a requirement for a "new breed" of indicators that are focused on service quality rather than on network performance. These are key quality indicators (KQIs) and each measures a specific aspect of product performance, product components/services or service elements, and they are calculated using data from a number of sources including the KPIs. At the highest level, a KQI, or a group of KQIs, is required to monitor the quality of the product offered to the end-user. These KQIs often form part of the SLA between the provider an