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

In differentiated services (DiffServ) 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 the same TCP flow, with the goal of improving the experienced performance. The paper presents an extensive performance evaluation of a new adaptive packet marking scheme, applied to a traffic scenario composed of TCP flows with different lengths. The proposed marking scheme is most efficient when applied to a scenario composed of all long-lived 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.