Class-based Bandwidth Allocation and Admission Control for QoS VPN with DiffServ

QoS VPN not only provides secured connections among multiple sites of a corporation over a publicly shared network infrastructure, but also provides different levels of QoS to different classes of traffic. In this paper, we study the problem of single-hop class-based bandwidth allocation and admission control with Diffserv. It is applied at the edge router/switch of a service provider´s core networks that provides QoS VPN service. We first present two basic approaches: static bandwidth allocation with parameter-based admission control, and dynamic bandwidth allocation with parameter-based admission control. Then we propose a new dynamic bandwidth allocation scheme with (1) measurement-based admission control, (2) priority-class advance reservation, and (3) bandwidth reallocation with load bound. Simulation results show that this scheme improves network utilization, lowers the call block rate of higher priority-class and avoids serious SLA delay violation. We also study the relationship between delay sensitivity and admissible region, and show that with a small delay violation tradeoff, a much larger admissible region can be achieved