Stability and Convergence of TCP with Faster Congestion Feedback

TCP´s ability to adjust to network conditions heavily depends on congestion feedback from the network. Historically, timeout, packet loss detection and Explicit Congestion Notification have been used to deliver the feedback. However, it has been discovered that TCP using ECN and RED is not stable in high-speed networks or in long round-trip time connections, and can lead to large oscillations, packet losses and timeout. In this paper, we prove that TCP with faster congestion feedback, such as with the Mark-Front Strategy, has larger stability region and therefore is more suitable for high-speed and long round-trip time connections. With numerical calculations we also show that TCP with faster congestion feedback converges quicker to its steady state. Simulation results validate the benefits of better stability and quicker convergence.