This tool analyzes network traces of TCP connections. Given a Microsoft Network Monitor trace, the analyzer provides various performance statistics and visualizations for the captured TCP connection. Included are plots of the time-sequence graph, round-trip time measurements, and more. The tool also contains an analysis engine that attempts to explain what the limiting performance factor of a particular connection was, such as limited physical bandwidth, network congestion, or a receiver or sender window size that is too small. The tool helps determine why a particular TCP connection is slow and enhances understanding of what a connection is doing. Note: Microsoft Research TCP Analyzer (x64) includes the installer for 64-bit Windows.