Modeling TCP/RED: a dynamical approach

Interaction between Transmission Control Protocol (TCP) and Random Early Detection (RED) gateways can be captured using dynamical models. The communication network is viewed as a discrete-time feedback control system where TCP adjusts its window size depending on whether or not it has detected a packet loss during the previous round trip time (RTT) interval. In this article, we describe a discrete-time nonlinear dynamical model for interaction between TCP and RED gateways. The model, constructed using an iterative map, captures a detailed dynamical behavior of TCP/RED, including slow start, fast retransmit, and timeout events common in TCP. Model performance for various RED parameters is evaluated using ns-2 network simulator.