A robust and high-performance queue management controller for large round trip time networks

Abstract

Congestion management for transmission control protocol is of utmost importance to prevent packet loss within a network. This necessitates strategies for active queue management. The most applied active queue management strategies have their inherent disadvantages which lead to suboptimal performance and even instability in the case of large round trip time and/or external disturbance. This paper presents an internal model control robust queue management scheme with two degrees of freedom in order to restrict the undesired effects of large and small round trip time and parameter variations in the queue management. Conventional approaches such as proportional integral and random early detection procedures lead to unstable behaviour due to large delay. Moreover, internal model control–Smith scheme suffers from large oscillations due to the large round trip time. On the other hand, other schemes such as internal model control–proportional integral and derivative show excessive sluggish performance for small round trip time values. To overcome these shortcomings, we introduce a system entailing two individual controllers for queue management and disturbance rejection, simultaneously. Simulation results based on Matlab/Simulink and also Network Simulator 2 (NS2) demonstrate the effectiveness of the procedure and verify the analytical approach.

Keywords:

• congestion control
• internal model control
• large delay
• queue management
• robustness

Additional information

Notes on contributors

Ladan Khoshnevisan

Ladan Khoshnevisan received the BS degree from University of Science and Technology, Tehran, Iran in 2008, and the MSc degree from Tarbiat Modares University, Tehran, Iran in 2010 both in electrical engineering. Her research interests include robust and adaptive control systems, congestion and flow control in computer networks, fault detection and isolation, and fault tolerant control. Currently, she is a Ph.D. student of control engineering at the University of Tehran, Tehran, Iran.

Farzad R. Salmasi

Farzad R. Salmasi received the BS degree in electrical engineering from the Sharif University of Technology, Tehran, Iran, in 1994, the MSc degree in electrical engineering from the Amirkabir University of Technology, Tehran, in 1997, and the Ph.D. degree in electrical engineering from Texas A&M University, College Station, TX, in 2002. From 1999 to 2002, he was a research assistant with the Advanced Motor Drives and Hybrid Vehicles Laboratory, Department of Electrical Engineering, Texas A&M University. From 2002 to 2004, he was with the Electro Standards Laboratories, Cranston, RI, as a research scientist. Since September 2004, he has been with the School of Electrical and Computer Engineering, Faculty of Engineering, University of Tehran. He has been the head of Control System Department since 2009. His main research areas include fault tolerant control, networked control systems and mechatronics. Dr Salmasi is an IEEE senior member.