Fairness evaluation of the default highspeed TCP in common operating systems

Since the TCP protocol implements in the Internet, the AIMD algorithm has always been the dominating congest control algorithm for about 20 years, and most of the common operating systems follow the recommendation of the IETF to adopt the AIMD algorithm in their TCP variations. But in recent years, many high-speed congest control algorithms have been proposed for fast data transfer over high speed and long distance networks, and many operating systems take the high-speed TCP variations as default: the Linux kernel uses CUBIC TCP as default since version 2.6.18, while Compound TCP becomes default TCP in Windows Server 2008 and a part of Microsoft Windows Vista, where it is easy to be enabled. As there are still not sufficient and comprehensive performance comparison of the high-speed TCP variations, the deployment of them as default TCP in the operating systems raises concerns about the future of congest control in the internet and worries about the fairness problem. This paper is an attempt to evaluate the fairness of the default TCP in the newest Linux and Microsoft Windows. The simulation results indicate that between CUBIC TCP and Compound TCP it indeed exhibits unfairness. The CUBIC TCP is too aggressive to the Compound TCP in the high bandwidth-delay product network, and the performance of Compound TCP is unacceptable comparing to CUBIC TCP.