Fairness Comparisons between TCP Reno and TCP Vegas for Future Deployment of TCP Vegas

TCP Vegas version is expected to achieve higher throughput than TCP Tahoe and Reno versions, which are currently used in the Internet. However, we need to consider a migration path of TCP Vegas when it is deployed in the Internet. In this paper, we focus on the situation where multiple TCP Reno and Vegas connections coexist at the bottleneck router, by which the fairness property is investigated to seek the possibility of future deployment of TCP Vegas. We consider drop-tail and RED (Random Early Detection) algorithms as buffering discipline at the router, and evaluate the effect of RED algorithm on fairness enhancement. From the analysis and the simulation results, we have found the results that the fairness between TCP Reno and Vegas can not be kept at all with drop-tail router. Although RED algorithm improves the fairness to some degree, there are inevitable trade-off between fairness and throughput.