Abstract—Active Queue Management (AQM) can potentially reduce packet loss rate in the Internet. This is used by routers for control congestion, where packets are dropped before queues become full. It has been shown that the transmission control protocol (TCP) connections through the congested routers can be modeled as a feedback dynamic system. In this paper, a new framework of AQM, namely Variable Structure (VS) based control scheme to handle delays in active queue management algorithm supporting explicit congestion notification (ECN), is proposed. The objective of the new algorithm is to improve performance of congested routers by keeping link utilization high, stable queue size and packet drop rate low. By examining the robustness and system response for the nonlinear TCP/AQM model, we present that the proposed scheme has good performance and robustness with respect to the uncertainties of the round-trip time (RTT) and the number of active TCP connections. The planned AQM is implemented with help of ns2 simulator. The simulation shows that the proposed design outperforms the peer AQM schemes in terms of packet loss, link utilization and buffer fluctuation.
Index Terms—Active queue management, Congestion control, Explicit Congestion Notification (ECN), robustness, stable queue size, variable structure control.
V. Santhi is working as a Lecturer in Department of Computer Science and Engineering, PSG College of Technology, Coimbatore-641 004,TamilNadu, India. Phone:+91-98427-28113 (e-mail:firstname.lastname@example.org).
Dr. A. M. Natarajan is working as CEO & Professor, Bannari Amman Institute of Technology, Sathyamangalam, Coimbatore, Tami lNadu, India (e-mail: email@example.com).
Cite: V. Santhi and A.M. Natarajan, "Performance Improvement on the Robustness of TCP/Active Queue Management with ECN," International Journal of Engineering and Technology vol. 2, no. 3, pp. 278-285, 2010.