Using adaptive priority scheduling for service differentiation in QoS-aware web servers

The current best-effort service model used on the Internet treats all requests uniformly, both in the network and at the application level. However, sometimes it is desirable to provide different classes or levels of service in order to satisfy the needs of different users and applications. In this paper, we propose an architecture for the provision of differentiated services at the web server level. The architecture is verified by means of a simulation model and real web server traces are used as workload. Two priority-based algorithms are implemented in the architecture aiming at service differentiation. The adaptive algorithm, an innovative solution at the application domain, allows the tuning of the priority level provided and determines how strict the use of priorities will be. The system can then adapt itself to various workloads, an essential feature in a highly dynamic environment such as the Web.