An empirical evaluation of wide-area internet bottlenecks

Performance limitations in the current Internet are thought to lie at the edges of the network -- i.e last mile connectivity to users, or access links of stub ASes. As these links are upgraded, however, it is important to consider where new bottlenecks and hot-spots are likely to arise. Through an extensive measurement study, we discover, classify and characterize non-access bottleneck links in terms of their location, latency and available capacity. We find that nearly half of the paths explored have a non-access bottleneck with available capacity less than 50 Mbps. The bottlenecks identified are roughly equally split between intra-ISP links and links between ISPs. These results have implications on issues such as the choice of access providers and route optimization.