Performance evaluation of a new adaptive packet marking scheme for TCP over DiffServ networks

In Differentiated Services networks, packets may receive a different treatment according to their Differentiated Services Code Point (DSCP) label. As a consequence, packet marking schemes can be devised to differentiate packets belonging to a same TCP flow, with the goal of improving the experienced performance. This paper presents an extensive performance evaluation of a new adaptive packet marking scheme, applied to a traffic scenario composed of TCP flows with different length. The proposed marking scheme is most efficient when applied to a scenario composed of all longlived flows. In a realistic mixed traffic scenario, composed of both long-lived and short-lived TCP flows, our marking scheme provides excellent performance in high utilization conditions, and still provides improved performance in medium utilization conditions, comparable with that achieved by a recently proposed marking algorithm specifically devised for short-lived flows. We also propose a “three colors” marking scheme, which merges this approach with ours to achieve improved performance in all utilization conditions.