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High-performance networks play a vital role in our increasingly interconnected world, and researchers in the NSF-funded Measurement and Network Analysis group of the National Laboratory for Applied Network Research (NLANR/MNA) are endeavoring to understand and improve the performance of the vital international networks that bridge continents, countries, and cultures.

To study these networks, the researchers deploy Active Measurement Project monitors across the Internet. Now, ongoing efforts by Ronn Ritke, Principal Investigator of NLANR/MNA, based at the San Diego Supercomputer Center (SDSC) at UC San Diego, and Tony McGregor, Active Measurement Project (NLANR/AMP) Project Manager, have led to deployment of the first AMP monitors in Africa, with two monitors installed in South Africa, and groups in Tunisia, Kenya, Senegal, and Morocco also asking to install AMP monitors and participate in the project.

"We're excited about the growth in Africa," adds Ritke. "Each new region that joins the monitoring project gives additional information that enriches our understanding of international networks. In addition, these outreach efforts to engage new areas expand our ability to measure the digital divide and the edges of the Internet." There are already more than 160 AMP monitors deployed in 25 countries on the continents of North and South America, Europe, Asia, Africa, and Australia. An online map showing the participating countries is at http://mna.nlanr.net/International/.

The growing international AMP "mesh" allows the researchers to monitor performance in network infrastructure to both highlight progress and identify problems on international links. The project also makes this measurement data widely available to other researchers, Ritke adds, which is becoming increasingly important with the rapid growth of traffic on those links and as multinational projects become more dependent on them.

"People often take the network connections between computers for granted," said Vijay Samalam, executive director of SDSC and division director of Technology R&D. "But high-performance international networks can be temperamental under the best of conditions, so the NLANR AMP initiative promoting cooperative research is vital to the performance of these networks, and we're pleased at the growing worldwide interest in participating."

In placing AMP monitors in Africa, the NLANR researchers at SDSC are collaborating with Steve Huter and the Network Startup Resource Center (NSRC). Based at the University of Oregon, the NSRC provides technical information, engineering assistance, training, and equipment to universities, research institutions, and networking organizations in developing regions of the world. The primary goal of the NSRC, which is partially supported by the NSF, is to make it easier for U.S. scientists and engineers to collaborate via the Internet with their international colleagues.

Over the past fifteen years, the NSRC has helped develop and deploy networks in Asia and the Pacific, Africa, Latin America, as well as the Caribbean, the Middle East, and the New Independent States. Working directly with African network engineers, the NSRC has assisted numerous countries with establishing their initial connections to the Internet in the 1990s. The NSRC continues to collaborate with colleagues all over Africa to enhance infrastructure in university networks, help organize technical training programs for African engineers, and establish national research and education networks.

International efforts began with just two AMP machines located internationally in 1999, and the program continues to grow at an accelerating rate. Over many years, NLANR/MNA has gained a reputation as a neutral party, Ritke explains, and this has facilitated the cooperation and trust necessary to extend the AMP mesh and place monitors across many different organizational and national boundaries.

The network analysis infrastructure created by the NSF-funded NLANR/MNA group is used for their own research and also supports the efforts of a growing number of outside researchers, system administrators, and students who are collaborating with the researchers. Network measurements are crucial for identifying and locating problems such as malfunctions, bottlenecks, inefficiencies, and incompatibilities in ultrafast research networks and high-speed international links.

The NLANR/MNA researchers assess network performance by measuring the flow of message traffic and analyzing performance issues. The AMP project carries out site-to-site active measurements and analyses by inserting test messages into the networks and observing the progress of the messages through the systems to determine such factors as routing pathways, round-trip times, and packet loss between sites. In addition to gathering data, the AMP project also analyzes long-term, large-scale trends in message flow patterns. The measurement devices for the AMP project are rack-mounted PCs with high-speed network cards, installed in the network equipment racks of participating universities and research institutions.

To benefit the international network community, the AMP project makes all data, analyses, and tools accessible to the network engineering and research community worldwide to ensure that networks can be tuned for maximum end-to-end performance. All participation is voluntary, and the program has gained wide acceptance because of strict privacy features, which both NLANR/MNA and participating sites are meticulous about maintaining. To do this, the researchers collect statistics about the message traffic, without reading the content of any messages. If they were working with the Post Office instead of high-speed networks, their devices would be writing postcards that they send to each other, and reading only the postmarks on their own mail, while completely ignoring all other mail. -Paul Tooby.