NLANR/DAST Releases Iperf 2.0

By Herbert Morgan, NCSA

The National Laboratory for Applied Network Research/Distributed Applications Support Team (DAST) has released Iperf 2.0, a major advancement from the previous version 1.7.0 (released May 2003). Primarily used by network engineers for testing a network, Iperf measures maximum TCP bandwidth and allows the tuning of various parameters and UDP characteristics.

Iperf 2.0 is a major rewrite. "It's a modernization," says John Estabrook, DAST member responsible for maintaining and packaging version 2.0, "and modernization is needed after four years of development." This version incorporates major changes in the underlying source code, which was completely rewritten by former DAST research assistant Kevin Gibbs. It retains all of the functionality of the earlier version and includes a major revision to the threaded nature of Iperf.

Version 2.0 will be the final major release for this three-year cycle of funding, according to Estabrook. He expects to continue making bug fixes and improvements through the next year in response to concerns and suggestions from Iperf users. But there are no plans for major development following this release.

All Iperf releases, since the initial release developed by Mark Gates, have come about in response to the user community. "And that's really appropriate," says Estabrook, "Iperf 2.0 was developed in conjunction with modifications suggested by users."

For example, this version of Iperf addresses some security issues, as suggested by one Iperf user, to avoid a denial-of-service attack. Although rare, it provides an added measure of safety.

In the past, Iperf support was conducted via email to the DAST mailing list, and response was one-to-one. DAST plans to develop a more user-friendly Web site devoted solely to supporting the community—answering questions, submitting bug reports and fixes—in a sense, outsourcing the work to the user community. The Web site will be linked to an Iperf repository, consisting of bug fixes and announcements for minor releases.

The goal is to get enough community support to allow users to continue with development and maintenance, not only for Iperf but for all DAST tools. By having released stable and useful tools, with DAST support, users themselves can provide patches for bug fixes, help maintain the tools, and carry them forward into open source.

This approach has been a success thanks to the contributions of the Iperf users group and newsgroup.

Developers who worked on Iperf 2.0 were Kevin Gibbs, John Dugan, and John Estabrook. Ajay Tirumala and Feng Qin helped to develop previous versions of Iperf.