We view congestion control as a distributed primal--dual algorithm carried out by sources
and links over a network to solve a global optimization problem. We describe a multilink
multisource model of the TCP Vegas congestion control mechanism. The model provides a
fundamental understanding of delay, fairness and loss properties of TCP Vegas. It implies
that Vegas stabilizes around a weighted proportionally fair allocation of network capacity
when there is sufficient buffering in the network. It clarifies the mechanism through which …

This paper presents a model of the TCP Vegas congestion control mechanism as a
distributed optimization algorithm. Doing so has three important benefits. First, it helps us
gain a fundamental understanding of why TCP Vegas works, and an appreciation of its
limitations. Second, it allows us to prove that Vegas stabilizes at a weighted proportionally
fair allocation of network capacity when there is sufficient buffering in the network. Third, it
suggests how we might use explicit feedback to allow each Vegas source to determine the …