Integrating Web server and network QoS to provide end-to-end service differentiation

We propose an integrated quality of service (QoS) manager (IQM) that determines and enforces the QoS given to HTTP requests that a Web server receives. In order to determine the required QoS, both the identity of the client as well as the URL being accessed are used. To provide end-to-end service guarantees, it is not sufficient to provide QoS in the network layer or in the Web server alone. QoS should be monitored and enforced in both components and the two managers must communicate and cooperate. Nowadays, Web servers are not restricted to doling out static Web documents, but usually execute some code for each HTTP request. The IQM determines the necessary QoS such that this execution is done within the specified deadline. The IQM is aware of network latency associated with each host and for each DiffServ marking, since ignorance about this delay can lead to deadlines being missed when the network load is high. We also show how dynamic DiffServ marking can help under high traffic conditions.