The utility of feedback in layered multicast congestion control
Sergey Gorinsky, Harrick M. Vin · 2001
Abstract — Layered multicast is a common approach for dissemination of audio and video in heterogeneous network environments. Layered multicast schemes can be classified into two categories – feedback-based and feedback-free – depending on whether or not the scheme delivers feedback to the sender of the multicast session. Advocates of feedback-based schemes claim that the feedback is necessary to match the heterogeneous receiver capabilities efficiently. Supporters of feedbackfree schemes believe that feedback introduces significant complexity and that a moderate amount of additional layers can balance any benefit the feedback provides. Surprisingly, there has been no systematic evaluation of these claims. This paper compares feedback-based and feedback-free schemes quantitatively with respect to their abilities to align the provided service to the capabilities of the heterogeneous receivers. We believe that such an evaluation supplies valuable insights and guidelines to the designers of future multicast congestion control protocols. 1