An analytical evaluation of VoD traffic treatment within the EF-enabled DiffServ ingress and interior nodes

The differentiated services (DiffServ) expedited forwarding (EF) per-hop behavior (PHB) is targeted on applications which need strict guarantees of end-to-end delay and should not suffer from packet losses. It makes EF PHB an appropriate choice for loss-free timely delivery of delay and loss intolerant traffic. It is expected that the substantial part of such sort of traffic will be generated by video-on-demand (VoD) services. In order to provide transmission service that is based on EF PHB to VoD traffic, several traffic-conditioning functions have to be implemented within the DiffServ ingress nodes. These conditioning functions are based on traffic profiles. In this paper, we show how to compute EF PHB traffic profiles for VoD traffic, which are based on simple token bucket mechanism and consider the effect of traffic profile violations. We evaluate both aggregated traffic and per-source quality of service (QoS) degradations caused by traffic profile violations. In order to compute the parameters of EF PHB queue within the DiffServ ingress node, approximation of the output stochastic process is done from the first queuing system by arrival curve. We also consider the VoD traffic treatment within DiffServ interior nodes and show how to compute parameters of EF queues within those nodes.