Stability of TCP/RED Systems in AQM Routers

Abstract

By applying the time-delay control theory to a TCP/RED dynamic model, this note establishes some explicit conditions under which the TCP/RED system is stable in terms of the average queue length. Then, the stability region is discussed. Finally, the results are illustrated by using 2 simulations, which demonstrates that it is able to choose an appropriate control parameter max of RED based on the stability conditions derived in this note, to achieve satisfactory network performance. It is found, by comparison, that this improved performance is better than that of three other typical active queue management (AQM) schemes-the random exponential marking (REM), proportional-integral (PI) controller, and adaptive virtual queue (AVQ) schemes.Index Terms-Active queue management (AQM), random early detection (RED), stability, time-delay control.

The use of a non-integer order PI controller with an active queue management mechanism

“…TCP/RED system becomes unstable when the round-trip delay and link capacity increase, and the number of TCP sessions decreases (Tan et al, 2006). A number of studies how to improve the basic algorithm have appeared; their comparison may be found, e.g., in the work of Hassan and Jain (2004).…”

Stable Queue Management for Supporting TCP Flows over Wireless Networks

“…The following linearized fluid model [1], [2] describes the dynamics of the TCP congestion window size and the queue length at the bottleneck router:…”

“…Given the ever-increasing demand for Internet access anywhere, anytime, congestion control for wireless networks is critically important. Although the stability of the Internet using TCP congestion control and AQM schemes has been extensively investigated [1], [2], [3], [4], effective congestion control for wireless networks is an open issue.…”

Novel delay-range-dependent stability analysis of the second-order congestion control algorithm with heterogonous communication delays

“…Several recent studies in Alpcan and Basar (2005), Guo et al (2007), Liu et al (2005), Low et al (2003), Massoulie (2002), Paganini (2002), Paganini et al (2003), Ranjan et al (2006), Tan et al (2006), Tian (2005a, b), Tian and Yang (2004), Wang et al (2002), Zhang et al (2007) and Ying et al (2006) have successfully dealt with heterogeneous delays, and have obtained several sufficient conditions for the local and global stability of some congestion control algorithms such as the discrete and continuous first-order primal algorithms, the dual algorithms and the primal-dual algorithms. The methods used to investigate the stability issue include the game-theoretic approach, Razumikhin's theorem, and the general Nyquist criterion in frequency domain.…”