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Broadcast-quality video is the key to any distance-learning application. A typical videoconference can eat up about half a T1 connection on Ohio's state backbone network, for instance, and it's not broadcast quality. It's difficult to reach that kind of quality over a T1, especially if the line also is being used for data, as is the case with the state's network, says Robert Sanders, director of distance education for both the Clermont County Educational Service Center and Hamilton County Educational Service Center. "Using MPEG II compression on the new network, I've seen high-quality video at even 1.5 Mbps, with very little pixelization," reports Sanders.

The SWORD Learning Network replaces Clermont County's DS-3 service, which was tariffed by Cincinnati Bell for video-only. The move to the ATM-based service has saved the school system about $200 per month over its existing DS-3 connection, and it will save even more without the extra data lines that it required. "Depending on what a school district had for data lines, the monthly savings could range from $150 to $700," says Sanders. The key to saving money up front with ATM is avoiding the equipment costs associated with rolling your own private ATM network. The only hardware Clermont had to purchase was an Optivision codec and a Cisco 3600 router for each site--Cincinnati Bell supplied the 3Com 3000 switches, where the ATM service terminates.

But pioneering a broadcast-quality video network also has trade-offs. The next hurdle is finding a gateway to connect the new MPEG II fiber ATM network to the state's T1 ATM network, which uses Vtel equipment and H.321 compression. That way, students and teachers will be able to hold videoconferences with organizations on the state network. Voice traffic will join the network sometime next year, and streaming video is expected to follow eventually.