A non-equilibrium analysis & control framework for communication networks

Tansu Alpcan, Paul Wang, Prashant G. Mehta, Tamer Başar

Research output: Chapter in Book/Report/Conference proceedingConference contribution


We present a non-equilibrium analysis and control approach for the Active Queue Management (AQM) problem in communication networks. Using simplified fluid models we carry out a bifurcation study of the complex dynamic queue behavior to show that non-equilibrium methods are essential for analysis and optimization in the AQM problem. We investigate an ergodic theoretic framework for stochastic modeling of the non-equilibrium behavior in deterministic models and use it to identify parameters of a fluid model from packet level simulations. For computational tractability, we use set-oriented numerical methods to construct finite-dimensional Markov models. Subsequently, we develop and analyze an example AQM algorithm using a Markov Decision Process (MDP) based control framework. The control scheme developed is optimal with respect to a reward function defined over the queue size and aggregate flow rate. We implement and simulate our illustrative AQM algorithm in the ns-2 network simulator. The initial results obtained confirm the theoretical analysis and exhibit promising performance when compared with well-known alternative schemes under persistent non-equilibrium queue behavior.

Original languageEnglish (US)
Title of host publicationFinal Program and Book of Abstracts - NOLCOS 2007
Subtitle of host publication7th IFAC Symposium on Nonlinear Control Systems
PublisherIFAC Secretariat
Number of pages6
EditionPART 1
ISBN (Print)9783902661289
StatePublished - 2007

Publication series

NameIFAC Proceedings Volumes (IFAC-PapersOnline)
NumberPART 1
ISSN (Print)1474-6670


  • Active queue management
  • Communication networks
  • Markov models
  • Optimal control

ASJC Scopus subject areas

  • Control and Systems Engineering


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