An evaluation of fairness among heterogeneous TCP variants over 10Gbps high-speed networks

Several high speed TCP variants are adopted by end users and therefore, heterogeneous congestion control has become the characteristic of newly emerging high-speed networks. In contrast to homogeneous TCP flows, fairness among heterogeneous TCP flows now depends on router parameters such as queue management scheme, buffer size, etc. To the best of our knowledge, this is the first evaluation of fairness among heterogeneous TCP variants over 10Gbps high-speed networks. Our evaluation scenarios for heterogeneous TCP flows consist of TCP variants with substantial presence in current Internet; therefore, TCP-SACK, CUBIC and HSTCP compete for bottleneck bandwidth. Experimental results for fairness are presented for different queue management schemes such as Drop-tail, RED, and CHOKe with varying degree of buffer sizes. We observed heterogeneous TCP flows induce more unfairness than homogeneous ones. RED and CHOKe improve fairness for large buffer sizes as compared to Drop-tail, whereas all three show similar fairness behavior for small buffer sizes.