How to make assured service more assured

摘要

In this paper, we study why the current assurance services (AS) architecture with profilers/markers at edge routers and with queue management mechanisms (RIO) at core routers cannot achieve throughput assurance and fairness. Based on the findings of the simulation study, we propose an enhanced version of the time sliding window (TSW) profiler, called the enhanced TSW (ETSW). We also design two enhanced versions of the RIO queue management mechanism, based on rigorous, analytical reasoning, called respectively, the (r,RTT)-adaptive algorithm and the dynamic RIO (DRIO) algorithm. To validate the proposed design, we implement the proposed mechanisms, along with the 2-window TCP scheme, the three color-marker scheme, and the CSFQ scheme in ns-2, and examine their behavior under a variety of network topologies and traffic sources. The simulation results indicate that both DRIO and (r,RTT)-adaptive algorithms, when combined with ETSW, do fulfill better throughput assurance and fairness, especially under the case that AS flows require different target rates, incur different round trip times, or co-exist with non-responsive UDP flows.