Analysis of VBR VoIP traffic for ad hoc connectivity with a fixed IP network

We study how to provide end-to-end QoS (quality of service) between nodes in a mobile ad hoc network and a fixed IP network that supports differentiated services (DiffServ). The ad hoc network incorporates a stateless wireless ad hoc networks (SWAN) scheme to support service differentiation. SWAN uses local rate control for best-effort traffic and sender-based admission control for real-time traffic. Best-effort traffic and real-time flows that have not yet been admitted as real-time sessions are delayed by a best-effort traffic shaper. In this paper, we propose FA-SWAN (fast admission-SWAN), a modified version of the SWAN QoS scheme. In contrast to SWAN, FA-SWAN enables the real-time flows to bypass the traffic shaper during the admission control process. Only after a real-time session is rejected as such, will the traffic be considered as best-effort and will have to be rate controlled. The results indicate that the modifications improve the performance of the voice application in comparison with the original SWAN.