A root cause analysis toolkit for TCP

TCP is the most widely used protocol for data transfer over the Internet and for most applications the performance metric of interest is throughput. Identifying the reasons for the throughput limitation of an observed connection is a complex task. We present a set of techniques, called the TCP root cause analysis toolkit, that allow users to determine from a passively captured packet trace the primary cause for the throughput limitation. We present the details of the toolkit and its validation and apply the toolkit to carry out a case study of ADSL traffic.