Sting: A TCP-based Network Measurement Tool
Understanding wide-area network characteristics is critical for evaluating the performance of Internet applications. Unfortunately, measuring the end-to-end network behavior between two hosts can be problematic. Traditional ICMP-based tools, such as ping, are easy to use and work universally, but produce results that are limited and inaccurate. Measurement infrastructures, such as NIMI, can produce highly detailed and accurate results, but require specialized software to be deployed at both the sender and the receiver. In this paper we explore using the TCP protocol to provide more accurate network measurements than traditional tools, while still preserving their near-universal applicability. Our first prototype, a tool called sting, is able to accurately measure the packet loss rate on both the forward and reverse paths between a pair of hosts. We describe the techniques used to accomplish this, how they were validated, and present our preliminary experience measuring the packet loss rates to and from a variety of Web servers.