Web Server Performance with Cubic and Compound TCP

Abstract

TCP congestion control mechanisms are used to prevent traffic volume from exceeding network resource limits. Consequently, they indirectly impact the performance of Web servers in a congested network. Systems running under Windows and Linux, including Web servers, use respectively the Compound and Cubic TCP congestion control variants that are designed for high-speed longdelay networks. We evaluate the performance under congestion of the popular Windows-based IIS and Linuxbased Apache Web servers when serving a single request from a browser. Specifically, we conduct experiments in a real test network with several routers to compare delay, throughput and shared bandwidth percentage when the Web server is subjected to various workloads under different levels of background network traffic. We find that IIS with Compound TCP has performance advantages over Apache with Cubic TCP when the two servers compete for bandwidth, but Apache has smaller delays than IIS for large and medium-sized files.