CUBIC High-speed Algorithms Implemented in Linux-2.6.31

Abstract

This paper investigates the congestion control capabilities of TCP-CUBIC introduced in Linux Kernel 2.6 for streamlining the kernel deploying CUBIC Congestion Control Protocol and similar High Speed variants. The end-to-end nature of the congestion control module is investigated to counter the trafficCUBIC is an enhanced version of BIC and a high speed variant for Transmission Control Protocol (TCP) in which the size of the window is a cubic function of time since the last lost event. It modifies the linear growth function of the window of the existing TCP standards into a cubic function such that the scalability of TCP would improve over the fast and long distance networks. CUBIC enables the window size to be increased aggressively when the window is far enough from the saturation point, and lets it to become slower when the window is close to the saturation point. This feature allows CUBIC to be very scalable when the bandwidth and delay product of the network is large, and at the same time, be highly stable and also fair to standard TCP flows. The implementation of CUBIC in Linux has gone through several upgrades. In this paper we present an initial design, implementation and performance.