CYRF: A theory of window-based unicast congestion control

NR Sastry*, SS Lam

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)


This work presents a comprehensive theoretical framework for memoryless window-based congestion control protocols that are designed to converge to fairness and efficiency. We first derive a necessary and sufficient condition for stepwise convergence to fairness. Using this, we show how fair window increase/decrease policies can be constructed from suitable pairs of monotonically nondecreasing functions. We generalize this to smooth protocols that converge over each congestion epoch. The framework also includes a simple method for incorporating TCP-friendliness.

Well-studied congestion control protocols such as TCP, GAIMD, and Binomial congestion control can be constructed using this method. Thus, we provide a common framework for the analysis of such window-based protocols. We also present two new congestion control protocols for streaming media-like applications as examples of protocol design in this framework: The first protocol, LOG, has the objective of reconciling the smoothness requirement of an application with the need for a fast dynamic response to congestion. The second protocol, SIGMOID, guarantees a minimum bandwidth for an application but behaves exactly like TCP for large windows.

Original languageEnglish
Pages (from-to)330-342
Number of pages13
JournalIeee-Acm Transactions On Networking
Issue number2
Publication statusPublished - Apr 2005
Event10th IEEE International Conference on Network Protocols (ICNP 2002) - PARIS, France
Duration: 12 Nov 200215 Nov 2002


  • congestion control
  • fairness
  • TCP-friendliness
  • transport protocols


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