A new scheme to improve fairness for assured service in differentiated services network

Issues related to fair sharing of bandwidth in Assured Forwarding based Differentiated Services networks have been discussed in many research papers. The factors that can bias fair sharing of bandwidth are Round trip time (RTT), packet size, the number of flows in aggregate and target rate etc. This paper proposes a new scheme to achieve proportional fair sharing of bandwidth among heterogeneous TCP flows for Assured Service. The Assured Services architecture relies on packet marking mechanism at the edge router, and AQM mechanism at the core router. In the new scheme the marking mechanism is FTSW2CM, which is based on TSW2CM algorithm. By measuring local throughput FTSW2CM can change the marking probability to achieve fairness. As to AQM mechanism we use MRIO algorithm, which can effectively stabilize the queue size and mitigate the "band-width skew" problem. The simulation results indicate that FTSW2CM+MRIO performs better than other popular schemes in providing fairness among heterogeneous TCP flows.