COLUMBUS, Ohio -- Researchers at Ohio State University have invented technology that lets data flow quickly and smoothly through a new kind of computer network.
This technology will help to vastly improve interactive computer applications like telemedicine, videoconferencing, distance learning, and high-tech home entertainment.
Asynchronous transfer mode (ATM) networks simultaneously transport multimedia data -- the digital components of text, graphics, audio, and video that create an interactive on-line experience -- from one computer to another at very high speed. Ohio State’s invention, which was recently presented at the ATM Forum, keeps multimedia data flowing steadily in ATM networks. The ATM Forum is a group of over 700 commercial and academic organizations worldwide working on standardizing ATM networks.
In traditional networks, for example the current Internet, computers bundle long streams of data into manageable packets for travel. The packets may be large or small. As the packets flow along wires to their destination across town, across the country, or across the world, they sometimes get separated.
Individual packets may follow different electronic paths, and arrive at their destination in the wrong order. Or -- just like cars trying to cross a busy intersection -- some packets may get caught in the slow traffic of the more congested areas of the Internet. Such errors and delays spell disaster for multimedia transmission.
“That’s why not many people can watch video on the Internet,” said Raj Jain, professor of computer and information science at Ohio State. “What most people see is just a single frame of the picture, and after a delay, the next frame. For continuous video, data must flow continuously.”
Even though each new generation of networking equipment offers faster connection speeds, the packets still travel according to the same old strategy.
“Speed alone doesn’t offer the guarantee of delivery that multimedia needs,” Jain said. “In addition to speed, ATM gives an uninterrupted connection, like a telephone.”
In ATM networks, data flows not in packets, but in cells of uniform size. All the cells for a single job travel along the same path from source to destination.
Still, if too many cells try to enter a network at the same time, they cause a traffic jam. To ease the flow of data in ATM, Jain and his colleagues devised a new way for networks to regulate the amount of data that comes in.
“Just like you have to manage automobile traffic on a highway, you have to manage data traffic in computer networks,” Jain said.
To regulate traffic, traditional networks have only two options: they can either drop the packets, or -- at best -- they can tell the computers that send data to speed up or slow down, depending on how crowded the network is. What current networks can’t do is tell the computers just how much to speed up or slow down.
With Ohio State’s new traffic management technique, explicit rate indication for congestion avoidance (ERICA), an ATM network tells its computers exactly how much data to send. As a result, the ATM network is never overloaded or underloaded.
For multimedia data, ERICA schedules the way text, graphics, voice, and video enter the network according to priority. Video, for example, must enter without delay for viewers to see a high-quality picture. Text, on the other hand, may wait for a short time without compromising the viewers’ experience.
Contact: Raj Jain, (614) 292-3989; Jain@cis.ohio-state.edu
Written by Pam Frost, (614) 292-9475; Frost.18@osu.edu
NOTE: PATENT AND LICENSING INFORMATION
Ohio State researchers have filed a patent application for ERICA. StrataCom, an ATM network equipment manufacturing company, obtained a nonexclusive license for the technology. Cisco Systems, another network company, acquired StrataCom in July of last year, and is licensed to incorporate ERICA into its latest line of products.
Right now, only academic and commercial facilities can take advantage of ATM. Jain says the technology probably won’t reach the average home computer for two to three years. Until then, he and his colleagues will continue to investigate ATM issues like data traffic management.