University of North Carolina at Chapel Hill Distributes Distance Learning Programming to Thousands
The University of North Carolina (UNC) at Chapel Hill is a leader in using video for educational purposes. It maintains an advanced video transmission network that cost-effectively transports high quality video images for distance learning, educational programming, telemedicine and teleconferencing, among other applications.
For example, students throughout the state can attend classes interactively via videoconferencing. The university can also transmit educational programming to the local cable television station, which sends it to households all over the Chapel Hill area, as well as to desktop computers on campus and throughout the world via the Internet.
UNC's Academic Technology and Networks (ATN) group is responsible for developing and maintaining the network infrastructure that transports these images, enabling different departments to transport compressed and uncompressed full-motion images around the campus. Its backbone transmits images from different sites to the studios that send them on to the end user. Departments send the images in a variety of formats. This means the backbone must support everything from 28.8 modem and compressed video to fully compressed digital and high-definition video.
Demanding applications that require low latency and high quality, such as telemedicine and distance learning, require a backbone that can send uncompressed images from studio to studio, ensuring high quality signals and low degradation. This is particularly important when signals leave UNC's campus and enter the wide area heterogeneous network environment, where analog and compressed signals can degrade after traveling through numerous pathways. Artel Video Systems provides the technology that enables the university to maximize its limited fiber-optic bandwidth, operate in a multi-vendor environment and provide an easy migration path from analog to digital transmission.
UNC has a fixed annual technology budget, so it must get the most functionality out of its video equipment for its money. Thus, the university uses mainstream, standards-based technology that will work in a multivendor environment, rather than being locked into a proprietary technology. "Artel's products maximize our fiber investment by allowing us to carry many signals over the same fiber. Because the company's products are standards based, we can mix and match transport technologies on our network if we ever need to. This enables us to have multivendor networks while staying in a digital domain, without having to do any transcoding," Johnson says. 'While the equipment may have cost more up front, from an operational and support perspective it is a more cost-effective, long-term solution. After plugging in the products two years ago, we've had zero failures and minimal maintenance."
The transmission products also provide UNC with an easy migration path from analog to digital, a challenge all broadcasters face due to the FCC's mandate to switch to digital transport by 2006. The university is using Artel's DigiLink 1220 series of transport equipment and a Utah-300 router to transport digital video while enabling campus studios to remain analog. By using dense wavelength division multiplexing (DWDM) technology, UNC can transmit multiple audio, video and data signals via a single cable, saving administrators thousands of dollars that might have been spent installing additional fiber optic cables. The University's DWDM system has the advantage over electrical multiplexing in that it combines all types of formats and protocols on the same strand or strands of fiber. This configuration provides all the benefits of digital technology without forcing the university to rebuild its studios, rather enabling it to distribute audio, video and data in multiple formats.
"Artel's products support both analog and digital end sites, so as soon as our studios decide to migrate to digital we'll have the infrastructure in place to support them. In the meantime, we can continue to provide a high-quality transport while keeping our analog users on the network," Johnson explains.
Expanding to the Wide Area
Since UNC's ATN group standardized on the DigiLink transport and Utah equipment for central campus services, a number of the university's departments have decided to adopt the same switching and transport technology in order to provide full digital quality images to viewers. In addition, other universities have expressed interest in UNC's design. Johnson is hopeful that if these universities adopt a similar SMPTE 259M transport and switching architecture, it can seamlessly extend its infrastructure to other campuses.
To prepare for wide-area transmission, UNC is evaluating how to transport multiple channels of uncompressed video alongside of high-speed data on discrete optical frequencies. Until now, carrying video with data links in wide-area networks meant converting the video into expensive, and compressed, asynchronous transfer mode (ATM) or synchronous optical NETwork SONET formats for transporting.
UNC is also an Internet 2 site, doing research on transporting video streams over high-speed, packet-based IP networks. While Artel's SMPTE 259M uncompressed transport carries the highest quality production signals, it also serves as a backbone for Internet-based video transport all the way down to the individual desktop on campus, using MPEG1 and MPEG2, and eventually MPEG4. This dual service approach allows for the highest quality backbone transport for production sites, while maintaining the cost effectiveness of compressed video for the 30,000 end users.
Artel Video Systems, Inc.
This article originally appeared in the 09/01/1999 issue of THE Journal.