Dynamics of TCP/RED and a Scalable Control

— We demonstrate that the dynamic behavior of queue and average window is determined predominantly by the stability of TCP/RED, not by AIMD probing nor noise traffic. We develop a general multi-link multi-source model for TCP/RED and derive a local stability condition in the case of a single link with heterogeneous sources. We validate our model with simulations and illustrate the stability region of TCP/RED. These results suggest that TCP/RED becomes unstable when delay increases, or more strikingly, when link capacity increases. The analysis illustrates the difficulty of setting RED parameters to stabilize TCP: they can be tuned to improve stability, but only at the cost of large queues even when they are dynamically adjusted. Finally, we present a simple distributed congestion control algorithm that maintains stability for arbitrary network delay, capacity, load and topology.

• Type: Conference
• Year: 2002
• Where: INFOCOM
• Authors: Steven H. Low, Fernando Paganini, Jiantao Wang, Sachin Adlakha, John Doyle
• Keywords: Communications, INFOCOM 2002, Local Stability Condition, Multi-link Multi-source Model, Stability Region