An active queue management scheme for Internet congestion control and its application to differentiated services

We propose a new active queue management algorithm, called average rate early detection (ARED). An ARED gateway measures/uses the average packet enqueue rate as a congestion indicator, and judiciously signals end hosts of incipient congestion, with the objective of reducing packet loss ratio and improving link utilization. We show (via simulation in ns-2) that the performance of ARED is better than that of RED and comparable to that of BLUE in terms of packet loss rate and link utilization. We also explore the use of ARED in the context of the differentiated services architecture. We show analytically that the widely referenced queue management mechanism, RED with in and out (RIO) cannot achieve throughput assurance and proportional bandwidth sharing. We then extend ARED and propose a new queue management mechanism, called ARED with in and out (AIO), in the assured services architecture. To share surplus bandwidth in a rate-proportional manner, we incorporate into AIO the derived analytic results, and propose an enhanced version of AIO, called the differentiated-rate AIO (DAIO) mechanism.