Characterizing and Mitigating Web Performance Bottlenecks in Broadband Access Networks

We present the first large-scale analysis of Web performance bottlenecks as measured from broadband access networks, using data collected from two extensive home router deployments. We design and implement tools and methods to identify the contribution of critical factors such as DNS lookups and TCP connection establishment to Web page load times and characterize how they contribute to page load times in broadband networks. We find that, as the connection speeds of broadband networks continue to increase, other factors such as TCP connection setup time, server response time, and network latency are often dominant performance bottlenecks. Thus, realizing a “faster Web” requires not only higher download throughput, but also optimizations to reduce both client and server-side latency. We deploy three common caching optimizations inside home networks to reduce latency—content caching, TCP connection caching, and DNS caching—and evaluate their effects on the factors that contribute to page load times in broadband networks.