Session based differentiated quality of service admission control for Web servers

Recent advance-session based admission control (SBAC) has resulted in protecting the server from entering a regime in which latencies are excessive or session throughput collapses due to dropped requests and aborted sessions. The goal of this work is to introduce differentiated QoS to SBAC. We propose a two-threshold SBAC scheme (QSBAC). It can provide high throughput for preferred clients especially in overload situation. Furthermore, to adapt to varying traffic loads, a dynamic QSBAC (DQSBAC) scheme is also proposed. The experimental results show that comparing with SBAC scheme, both QSBAC scheme and DQSBAC scheme can sustain higher session throughput for preferred clients, as well as decrease aborted session percentage greatly. Comparing with QSBAC scheme, DQSBC scheme is more feasible because of its adaptation to varying traffic loads.