QoS Provisioning for VoIP Traffic by Deploying Admission Control

In this paper we propose a model-based admission control scheme for maintaining QoS of voice traffic over DiffServ networks. This CAC approach implies two main components. The first one is the application of the NJ (Negligible Jitter) conjecture extended to the case of heterogenous variable bit rate voice sources. The second one is the analysis of a finite queueing system with exhaustive service and multiple server vacations, which is motivated by the strict priority scheduling deployed in DiffServ-capable routers. Extensive analytical and simulation results are investigated to assess the applicability of the CAC proposal.