Measuring and mitigating web performance bottlenecks in broadband access networks

We measure Web performance bottlenecks in home broadband ac-cess networks and evaluate ways to mitigate these bottlenecks with caching within home networks. We first measure Web performance bottlenecks to nine popular Web sites from more than 5,000 broad-band access networks and demonstrate that when the downstream throughput of the access link exceeds about 16 Mbits/s, latency is the main bottleneck for Web page load time. Next, we use a router-based Web measurement tool, Mirage, to deconstruct Web page load time into its constituent components (DNS lookup, TCP con-nection setup, object download) and show that simple latency opti-mizations can yield significant improvements in overall page load times. We then present a case for placing a cache in the home net-work and deploy three common optimizations: DNS caching, TCP connection caching, and content caching. We show that caching only DNS and TCP connections yields significant improvements in page load time, even when the user’s browser is already performing similar independent optimizations. Finally, we use traces from real homes to demonstrate how prefetching DNS and TCP connections for popular sites in a home-router cache can achieve faster page load times