The Internet2 consortium has developed a software package for the End To End Performance Initiative called Performance Improvement Performance Environment System (PIPES). One particularly useful component of PIPES is the Network Diagnostic Tester (NDT).

NDT was developed by Richard Carlson, an engineer at Internet2. Carlson developed a signature-based engine that forms the core of NDT and the integration to make the system work. The result is a reliable, stable tool that differentiates itself from other common tools in greatly assisting network administrators in diagnosing network problems.

I have often referred my customers to throughput testing sites such as McAfee Inc.'s Internet Speedometer or DSLreports.com to test their bandwidth. However, these sites are only as accurate as the slowest pipe between client and server, and this almost always means the Internet connection. Their usefulness breaks down when measuring throughput within a local-area network.

A useful method for measuring throughput on a LAN is to use File Transfer Protocol to transfer a large file. FTP reports the average throughput for the transfer. However, FTP cannot report if network congestion or incorrectly configured links are adversely affecting the results.

NDT handles these issues, and much more. It's simple to set up on a Linux server with a web100-patched kernel. More importantly, the Web interface is simple enough for an end user to use, requiring only a click of the "Start" button and cutting and pasting the results in an e-mail to send to the networking staff.