On the Prospects of Chaos Aware Traffic Modeling

TL;DR

This paper investigates the chaotic properties of TCP congestion avoidance, revealing complex dynamics and proposing a hybrid model that captures both chaotic short-term behavior and periodic long-term patterns.

Contribution

It introduces a novel traffic model combining fluid equations with separate packet loss handling to better represent chaos in TCP networks.

Findings

Chaotic behavior occurs at short time scales in TCP congestion dynamics.

The phase space of congestion windows exhibits cellular structure implying periodicity.

The proposed model reproduces key features observed in realistic simulations.

Abstract

In this paper the chaotic properties of the TCP congestion avoidance mechanism are investigated. The analysis focuses on the origin of the complex behavior appearing in deterministic TCP/IP networks. From the traffic modeling point of view the understanding of the mechanism generating chaos is essential, since present models are unable to cope with this phenomena. Using the basic tools of chaos theory in our study, the main characteristics of chaotic dynamics are revealed. The dynamics of packet loss events is studied by a simple symbolic description. The cellular structure of the phase space of congestion windows is shown. This implies periodic behavior for large time scales. Chaotic behavior in short time scales and periodicity for larger times makes it necessary to develop models that account for both. Thus a simple model that describes the congestion window dynamics according to fluid equations, but handles the packet loss events separately is introduced. This model can reproduce the basic features observed in realistic packet level simulations.