A top-down approach to VoD traffic transmission over DiffServ domain using AF PHB class

Based on the differentiated services (DiffServ, [S. Blake, et al., December 1998]) model we develop implementation-ready transmission service for video-on-demand (VoD) traffic. In order to satisfy the demands of real-time nature of VoD traffic we propose to use assured forwarding (AF, [B. Davie, et al., March 2002]) per-hop behavior (PHB) group. We provide specific traffic profile parameters which adequately fit to VoD traffic requirements. Using these parameters and AF PHB class we show how to construct a well-defined transmission service that is suitable for VoD traffic delivery. Our service is analytically tractable. It means that using the quality of service (QoS) parameters which should be provided to VoD traffic we can evaluate the required capacity not only within the DiffServ ingress node, but within the interior nodes too. Our transmission service is designed in such way that it is fully characterized by the parameters of DiffServ ingress node, bounds the losses and delay along the path of behavior aggregate and allows us to predict the QoS degradation which can be experienced by both behavior aggregate and single microflows.