Proliferation of communication-intensive real-time applications with elastic" timeliness constraints, such as streaming stored video, requires a new design for endhost communication subsystems. The design should i provide per- ow or per-service-class guarantees, ii maximize the aggregate utility of the communication service across all clients, iii gracefully adapt to transient overload, and iv avoid, if possible, starving lower-priority service classes during the period of sustained overload. We propose a QoS-optimization algorithm and communication subsystem architecture that satisfy the above requirements. It provides each client its contracted QoS, while adapting gracefully to transient overload and resource shortage. A new concept of exible QoS contract is introduced, specifying multiple acceptable levels of service or QoS levels for short and their corresponding rewards for each client. Allowing clients to specify multiple QoS levels permits the server to perform QoS-optimiz...
Tarek F. Abdelzaher, Kang G. Shin