1 Patterns for Measuring Performance-related QoS Properties in Service-oriented Systems

In service-oriented systems, clients can access services via a network. Service level agreements (SLA) can exist, which specify — among other things — performance-related Quality of Service (QoS) properties between the client and the server, such as round-trip time, processing time, or availability. For a service provider serious financial consequences or other penalties can follow in case of not fulfilling the SLAs. The service consumer wants to evaluate that the provider complies with the guaranteed SLAs. Designing and developing a QoS-aware service-oriented system means facing many design challenges, such as where and how to measure the performance-related QoS properties. This paper presents design practices and patterns for measuring such QoS properties by extending and utilizing existing patterns. The focus of the patterns lies on the QoS measuring impact on the client’s or service’s performance, the extend of separation of concerns, the property of reusability, and the preciseness of the measured QoS properties. The patterns help to build efficient solutions to measure performance-related QoS properties in a service-oriented system