A DISCRETE-TIME MODEL OF TCP WITH ACTIVE QUEUE MANAGEMENT
Hui Zhang · Summit (Simon Fraser University) · 2004
The interaction between Transmission Control Protocol (TCP) and Active Queue Management (AQM) can be captured using dynamical models.The communication network is viewed as a discrete-time feedback control system, where TCP adjusts its window size based on packet loss detection during the previous Round Trip Time (RTT) interval.In this research, a discrete-time dynamical model is proposed for the interaction between TCP and Random Early Detection (RED), one of the most widely used AQM schemes in today's Internet.The model, constructed using an iterative map, captures the detailed dynamical behaviour of TCP/RED, including the slow start and fast retransmit phases, as well as the timeout event in TCP.Model performance for various RED parameters is evaluated using the ns-2 network simulator.The results are then compared with other existing models.Based on evaluations and comparisons of our results, we can conclude that the proposed model captures the dynamical behaviour of the TCP/RED system.In addition, the model provides reasonable predictions for system parameters such as RTT, packet sending rate, and packet drop rate.An extension of the proposed model is also presented, which is a dynamical model of TCP with Adaptive RED (ARED), a modified AQM algorithm based on RED. ACKNOWLEDGEMENTSI would like to thank my senior