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Abrupt transition to complete congestion on complex networks and control
Wen-Xu Wang1, Zhi-Xi Wu, Rui Jiang
1Department of Electrical Engineering, Arizona State University, Tempe, Arizona 85287, USA.
Chaos (Woodbury, N.Y.)
|October 2, 2009
Summary
Realistic networks with finite buffers exhibit abrupt transitions from free flow to complete congestion. A new control strategy using random packet dropping can prevent or break this congestion, optimizing traffic flow.
Area of Science:
- Network science
- Complex systems
- Communication networks
Background:
- Traditional traffic-flow models assume continuous transitions to congestion.
- Existing models do not fully account for finite buffer capacities in network nodes.
Purpose of the Study:
- Investigate traffic-flow dynamics in complex networks with finite node buffers.
- Explain the phenomenon of abrupt transition to complete congestion.
- Propose a control strategy to mitigate network congestion.
Main Methods:
- Utilized a conventional traffic-flow model based on the packet birth-death process.
- Incorporated finite buffer capacities for network nodes.
- Developed a mean-field theory to analyze the transition phenomenon.
- Performed numerical simulations for validation.
Main Results:
- Observed an abrupt transition from free flow to complete congestion, differing from continuous transitions.
- Identified an optimal routing parameter value that maximizes network traffic capacity just below the transition point.
- Validated the mean-field theory's explanation for the observed transition.
Conclusions:
- Finite buffer sizes in realistic networks can lead to sudden, complete congestion.
- A specific routing parameter can optimize network throughput.
- Random packet dropping is an effective strategy to prevent or resolve complete congestion in communication networks.
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