ices, or for attracting new customers by focusing on service quality. For service providers and third-parties the quality measurements can be used for services design and their offer- ing, for troubleshooting, for marketing purposes, as well as capacity planning and fur- ther service development. 7.7.1 QoS/QoE Measurement Systems The QoS measurement system aims to provide QoS measurements which can be com- pared to given targets and used for network/service monitoring or design/optimization purposes. Such a system should be easily understood by service providers and cus- tomers, and should be useful for QoS monitoring of services used by customers. Also, 7.7 QoS and QoE Assessment Methodologies QoS measurement systems provide input data for network dimensioning for capacity enhancements and its optimization. With the aim of making measurement results com- parable, the measurements should be independently repeatable by the same party or another party. Also, given QoS measurement system should be widely applicable for measurements of different traffic types, different link-layer technologies (e.g. Ethernet, WiFi, mobile access networks) and any IP network. For the purposes of QoS enforce- ment the QoS measurement system must be reliable and comparable with the SLA targets. There are certain requirements that quality measurement systems should comply with [19], which include the following: Accuracy. Measurement results should be reliable, reproducible and consistent over time, including both QoS and QoE indicators. Comparability. This refers to having comparable KPIs (which may be enforced by the NRA), SO the services from different service providers or from the same service provider in different regions or different customer packages can be compared. Trustworthiness. The measurement system components should be reliable over time, based on agreed procedures (e.g. between service providers and NRA, or according to regional QoS guidelines [19]) and also have to be protected against security attacks which may jeopardiz