PPrate: A Passive Capacity Estimation Tool

Knowledge of link capacities is essential, e.g., for ISPs to troubleshoot paths outside the boundaries of their networks. However, the vast majority of capacity measurement tools are based on active probing, which is not suitable for large scale studies of Internet paths characteristics. In this paper we present PPrate, a completely passive tool, that can extract capacity information of a path from the packet trace of a TCP connection. We validate PPrate using synthetic traces and real traces collected on PlanetLab. We compare PPrate with Pathrate, which is very accurate active tool, and show that they perform comparably. We finally apply PPrate on a large publicly available ADSL trace.