A Comprehensive Study of Modern and High Speed TCP-Variant in Linux Kernel: TCP CUBIC

Transmission Control Protocol TCP is no doubt most widely used congestion control protocol designed for highly reliable and end-to-end communication over the internet. TCP is not suitable in its standard form for modern and high speed networks. Various TCP variants are solution for this issue. CUBIC is a modern TCP variant designed for high speed and scalable networks. CUBIC is also adopted as default congestion control algorithm in Linux kernel. This survey paper contains a detailed discussion about TCP CUBIC and the directions for further improvements. It describes the CUBIC design architecture with the pseudo code of the algorithm, TCP support in Linux kernel and implementation of CUBIC, Network Simulator 2 and Network Simulator 3 based study of CUBIC along with its class diagram. Finally, the performance of CUBIC is evaluated both in wired and wireless environment under the parameters of goodput and intra-protocol fairness along with TCP NewReno and TCP Compound. The simulation results demonstrate that CUBIC is very suitable for wired and high speed networks but its performance degrades in wireless and low speed networks