Abstract: Based on the analysis of threctier Web applications,a state space model of a MIMO system supported differentiated service was proposed which breaks through the commonly transfer function ways. Then the controller was designed by pole placement and state feedback of control theory to adjust the resource quotas assigned to different classes in every tier and achieve the proportional delay guarantees. The experiments demonstrate that it is feasible to approximate the system to a group of low-level linear equations and the proposed controller can hold the relationship between different classes.

Key words: Differentiated services,Multi tier Web applications,State space model