Open-loop rate control for real-time video streaming: analysis of binomial algorithms

Emerging real-time streaming applications often rely on rate-based flow control. However, congestion control for rate-based applications is typically dismissed as being not viable due to the common notion that "open-loop" congestion control is simply "difficult." This paper sheds new light on the performance of binomial NACK-based (i.e., rate-based) congestion control and measures the amount of "difficulty" inherently present in such protocols. Even though previous work proposed several new congestion control methods for real-time streaming, our analysis shows that traditional additive-increase, multiplicative-decrease (AIMD) schemes possess the best packet-loss scalability among all proposed TCP-friendly schemes, especially when used in rate-based applications. We further confirmed our analytical results in a number of experiments using MPEG-4 Fine-Granular Scalable (FGS) streaming over a Cisco testbed.