On the Accuracy of Active Capacity Estimation in the Internet.

Estimating the capacity of network paths is a frequently and versatilely used technique for network and flow analysis used by service providers and researchers to analyze available bandwidth, performance limitations of connections, or infrastructure deployments. While researchers evaluated different capacity estimation approaches in the early 2000s, there are no recent studies on the accuracy of estimates and capacity deployments in today’s Internet.This paper is purposed to survey the accuracy of actively conducted capacity estimation in today’s Internet. We implement passive packet pair dispersion-based capacity estimation according to the PPrate algorithm and conduct active measurements with TCP and ICMP traffic on controlled targets in the Internet and on public web servers to analyze the accuracy and stability of estimated capacities in the Internet.Our study confirms the general accuracy of PPD-based measurements through the Internet while we observe and discuss impacts by interrupt coalescence, receive offloading, and ICMP rate limiting of middleboxes. Measurements to over 3500 web servers taken from the Alexa top 1M list indicate capacities of at least 1 Gbit/s for the majority of paths to measurement targets, while ICMP-based measurements frequently result in significant underestimation due to ICMP rate limiting.