A stable rate-based algorithm for active queue management

Abstract

This paper proposes a rate-based active queue management algorithm or RAQM. It uses the aggregated traffic input rate to calculate packet drop probability according to an exponential rule. The proposed RAQM algorithm works in two modes: queue-independent and queue-dependent. In the queue-independent mode, it only relies on the aggregate traffic input rate to regulate the input rate to the expected value, i.e. expected link utility. In the queue-dependent mode, it also uses the instantaneous queue length to further adjust the packet drop probability and to regulate the queue length to the expected value. We analyze the stability and investigate practical implementation issues of the RAQM. Simulations are carried out to study RAQM performance and to compare with other AQM algorithms, in particular PI and REM schemes. The results demonstrate that RAQM achieves better stability and faster response as it can quickly regulate the queue length to the expected value with small overshoot. RAQM also obtains better tradeoff between link utilization and queuing delay, and obtains higher goodput with the same buffer size as in PI and REM schemes. Finally RAQM has O(1) complexity, thus independent of the number of flows.