Uncovering Performance Differences Among Backbone ISPs With Netdiff

This paper designs and implements Netdiff, a system that enables detailed performance comparisons among ISP networks. It helps customers and applications determine, for instance, which ISP offers the best performance for their specific workload. Netdiff is easy to deploy because it requires only a modest number of nodes and does not require active cooperation from ISPs. Realizing such a system, however, is challenging as one must aggressively reduce probing cost and ensure that the results are robust to measurement noise. The paper describes the techniques that Netdiff uses to address these challenges. Netdiff has been measuring eighteen backbone ISPs since February 2007. Its techniques allow it to capture an accurate view of an ISP's performance in terms of latency within fifteen minutes.