Probabilistic Bandwidth Reservation by Resource Priority Multiplexing

Probabilistic bandwidth guarantees on variable bit-rate network ows o er signi cant improvements in throughput for only modest decreases in guarantee level. In this paper we present a probabilistic bandwidth reservation scheme for variable bit-rate ows called Resource Priority Multiplexing (RPM). The RPM algorithm uses packet marking on edge routers and selective dropping on core routers to provide perow speci cation of probabilistic QoS with guarantees ranging from best-e ort to hard reservation. RPM also supports multiple metrics for probabilistic level of service speci cation. All ow tables are managed only by the edge routers enhancing scalability of the approach. Unlike existing statistical multiplexing approaches, RPM uses a time-multiplexed priority tagging algorithm which provides higher control over ows guarantee levels. The algorithm has been implemented in a live system as part of the IP protocol stack and experimental results are presented.