Improvements achieved by SACK employing TCP Veno equilibrium-oriented mechanism over lossy networks

Abstract

Veno (see Fu ChengPeng et al., TCP Veno: Equilibrium-oriented End-to-end Congestion Control over Heterogeneous Networks, http://www.broadband.ie.cuhk.edu.hk) is a new version that employs the refined AIMD (additive increase and multiplicative decrease) congestion control algorithm with its implementation only on the sending side. In addition to achieving significant throughput improvement over Reno (particularly in wireless networks), Veno shows good compatibility and flexibility in heterogeneous networks. In this paper, we demonstrate the benefits of combining the retransmission strategy of SACK (selective acknowledgement) option with Veno's congestion control mechanism. Our implementation is referred as SACK TCP/sub Veno/, similar to the definition of SACK given by K. Fall and S. Floyd (see Simulation-based Comparisons of Tahoe, Reno, and SACK TCP, Computer Communication Review, July 1996), which refines the recovery strategy of Reno by using the SACK option (see Mathis, M. et al., TCP Selective Acknowledgement Options, RFC 2018, IETF, October 1996). By means of simulation and real network experiments, we demonstrate that SACK TCP/sub Veno/ can obtain a satisfactory throughput improvement over SACK TCP. Also, we show SACK TCP/sub Veno/'s compatibility with SACK TCP.