Flow-based reservation marking in MPLS networks

Abstract

Marking in DiffServ at the edge of the network often follows a demand side policy. It meters a traffic stream and marks its packets according to some predefined traffic parameters as Committed Information Rate, Committed Burst Size, Excess Burst Size and so on. Such marking based on traffic characteristics is irrespective to network dynamics, which causes collision and QoS degradation in DiffServ. This paper proposes flow-based Reservation Marking as a supply side marking at the network edge, which marks stream packets reserved or unreserved according to flow-specific reservation in a distributed resource reservation environment. When congestion occurs, anticipant per flow QoS is secured by protecting reserved packets on core routers without any per flow or per trunk management. It provides a simple, scalable and adaptive mechanism of implementing quantitative end-to-end QoS by mapping per flow in IntServ into per class in DiffServ. A "once reserve, no more manage" framework is constructed to eliminate flow state, avoiding unexpected collision and flow management simultaneously on core routers. Performance evaluation reveals that it affords controllable and quantitative QoS, keeps networks core-stateless and achieves high link utilization at the same time.