QoS management in distributed service oriented systems

The paper presents an approach to QoS management in distributed service oriented systems. We study the approach by the example of the Cassandra Framework developed at Philips Research. Cassandra is a distributed video/audio streaming and analysis platform consisting of a collection of loosely-coupled services, which can be easily combined to build distributed applications. To manage QoS of the system, two QoS attributes are selected: availability and performance. We tackle these issues in a service oriented fashion, making the system tolerant to service failures and adaptable to varying requirements of the applications