tions Systems Group of the Department of Electronic and Electrical Engineering at University College London and the Telecommunications Laboratory of the Department of Electrical Engineering and Computer Science at the National Technical University of Athens. 6 Service Provisioning and Activation manage custom data for intelligent network services present on the SCPs. It receives the definition of the information needed to provision the service from the SCE. The data necessary to provision the services can be sent to the service management sys- tem via manual entry or by an upstream system. The data are validated and routed to the appropriate SCPs by the service management system. An example of a network owner adding intelligence to its network was the sale by Nokia to Globe Telecom (Philippines) of a mobile switching centre (MSC) with a capacity of 150 000 subscribers. This expanded the capacity of Globe's Manila MSC from 120 000. Nokia also supplied a Home Location Register and the Nokia mobile IN solution. This solution added to Globe's ability to provide new value-added serv- ices to GSM (Global System for Mobile Communications) subscribers. In particular, Nokia's IN solution was seen as a step towards more efficient service provisioning. 6.4 Measuring QoS at the Customer Layer Providing services of a particular quality requires the monitoring of low-level net- work metrics since the behaviour of the network is ultimately the basis of the serv- ices that a customer receives. However, network-level metrics must be translated into customer-layer service quality metrics. This was once a labour-intensive task, but most service providers are now working towards automating the conversion of network-level metrics to service-quality metrics. In the past, verification testing could only be done by skilled field technicians and this manual work was a prerequisite to service activation. For each service type, standard procedures were followed and the network was optimised - typically for telephony and low-speed data tran