A method for QoS differentiation in DiffServ networks based on the long-term properties of a video stream

This paper presents a method for adjusting the level of services offered by the network with quality of service differentiation for the long-term characteristics of a transmitted video stream. The Drop Precedence (DP) field located in the header of IP packet for this purpose was used.The DP field is set dynamically, based on the measurement of the long-term properties of a source video stream entering the network. The level of traffic perturbations present in a stream is expressed by the Hurst parameter, and then mapped to the size of a priority encoded in the DP field. By that means, an adaptive differentiation of the preferences of individual streams within the same AF PHB class of service is implemented, depending on the size of perturbations existing in the flow. The use of the long-term Hurst parameter, as a criterion of classification, makes the treatment of packets marked with a given priority value does the job well on a larger time scale.