March 12, 2001
Shadow Service and Faster Lanes Unjam Traffic at the Pittsburgh GigaPoP
Network resources at the Pittsburgh Supercomputing Center support area universities.
PITTSBURGH September at university campuses means new students and a new year meeting the challenges of higher education. In recent years, it has also meant big jumps in Internet traffic. At the University of Pittsburgh this past September, Internet traffic exploded to more than twice the prior load. At Penn State, there was a similar burst, and at both campuses the result was jam-ups resembling rush hour on the Los Angeles Freeway.
The solution in both cases involved some fancy rerouting at a place called the Pittsburgh GigaPoP. This funny word short for Gigabit Point of Presence denotes a network crossroads that can accommodate very high volumes of message traffic. With a combination of advanced software and hardware ports, routers and switches, the GigaPoP works like an ultra high-speed post office to sort and route messages to their destination. The "Giga" part of GigaPoP means transfer rates of a billion bits per second or more. On the current fastest lane at the Pittsburgh GigaPoP, 2.4 gigabits per second, traffic moves fast enough to download 436 copies of the complete works of Shakespeare each second.
There are more than 20 GigaPoPs in the United States, and Pittsburgh's administered by crack network engineers at the Pittsburgh Supercomputing Center is among a select group. "In terms of the number of bits we can push, our installed infrastructure is matched only a few other places," says Gwendolyn Huntoon, who directs the National Center for Network Engineering, PSC's network resource group. "Just as importantly, the level of services we provide is very advanced." Multi-casting, a routing protocol that minimizes congestion from high-volume transmissions like video, is one example of the GigaPoP's advanced services.
The GigaPoP's primary job is to serve higher education and research, and its ability to do this makes it one of the key technology resources of the region. Its members include Carnegie Mellon, Penn State, the University of Pittsburgh and West Virginia University. At PSC in the Mellon Institute building on the border between the two Pittsburgh campuses fiber-optic cable from each of these universities meets up with several different "backbone" networks. These include high-performance research networks as well as so-called commodity Internet services, the regular Internet most of us use for e-mail and browsing the web.
"Demand for bandwidth is constantly increasing," says Huntoon. "What makes the GigaPoP unique is we add capacity on a regular basis so it's there before it's needed. We also have what we call shadow services connections that aren't in use but can be turned on at a moment's notice to relieve unexpected congestion." Such shadow services relieved this fall's traffic jam at Pitt.
All four member universities subscribe to Abilene, a high-performance network that links over 170 U.S. universities and research organizations. Data zooms along the Abilene backbone at 2.4 gigabits per second, and with recent upgrades, the GigaPoP link to Abilene has improved fourfold to 622 million bits per second. This and other upgrades provide sufficient bandwidth to avoid traffic jams for the present.
Along with administering the GigaPoP, PSC network staff serve as a resource nationally. For Internet2, the consortium of universities that developed Abilene, PSC staff provide technical training for member universities, and they test and evaluate new technologies. "Services we work on here," says Huntoon, "are deployed in the commercial sector within a year or two. That's because we've helped to identify and solve technical problems so that the services will work transparently in a production environment."
"Having a local resource that consolidates and accommodates not only the commodity Internet traffic but also enables next-generation research networks is absolutely critical in pursuing our academic and research missions," says Tracy Futhey, vice provost and chief information officer of computing services at Carnegie Mellon.
"The support and service provided by the GigaPoP has been invaluable in supporting the research and academic network requirements of the University of Pittsburgh," says Jinx Walton, who directs computing services and systems development at Pitt. "The flexibility they have been able to demonstrate over the past several months has allowed us to effectively accommodate the changing requirements of our students and faculty."
Many research applications require high-performance networks, especially when graphics are involved. PSC network staff are collaborating with scientists at the University of Pittsburgh Health System to develop technologies for "telemedicine," such as matching patient tissue samples against a database of already diagnosed tissue. At Carnegie Mellon, research on 3D modeling of dynamic events, similar to but more sophisticated than the instant-replay technology at this year's Super Bowl, also requires high-speed networks.
The Earth Systems Science Center at Penn State relies on Abilene for real-time exchange of meteorological data with the National Center for Atmospheric Research. In another application, Penn State professors and students of architecture use virtual-reality tools to share projects via Abilene with students and faculty at other universities.
At West Virginia University, the GigaPoP has fostered relationships with WVU's Japanese sister institution, Kansai Gaidai, in the city of Hirakata. Through the GigaPoP, PSC staff arranged to assure sufficient bandwidth for a video teleconference in virtual reality and multimedia. A high-speed fiber link to the GigaPoP from WVU and the National Energy Technology Laboratory in Morgantown also facilitates research on cleaner ways of burning fossil fuel.
Along with regional universities, the Pittsburgh GigaPoP also serves several commercial users. AT&T Broadband Network Solutions contracts for bandwidth that connects the Pittsburgh Public School District to the Internet. Westinghouse Electric Co. and SMS-Marconi also have acquired network services through the GigaPoP.
The Pittsburgh Supercomputing Center is a joint effort of Carnegie Mellon University and the University of Pittsburgh together with the Westinghouse Electric Company. It was established in 1986 and is supported by several federal agencies, the Commonwealth of Pennsylvania and private industry.