Videoconferencing on the Verge
Online collaboration has taken on fresh impetus since the 9/11 tragedy, with additional momentum provided by the economic downturn and the security-choked airports. Companies are eager to find alternatives to face-to-face meetings with associates, partners, suppliers and clients. Videoconferencing is taking a lead role in changing corporate practices. Analysts have been forecasting the take-off of videoconferencing for more than a decade, but this time they may be right: technology is reaching maturity; equipment prices are dropping; interfaces are becoming more user-friendly, and convergence is opening up new delivery channels.
Video conferencing can be divided into three groups: desktop, small group and conference room. In addition, there is a trend towards collaboration centers, in which videoconferencing may be supplemented by electronic whiteboards, multimedia feeds, document cameras and data conferencing.
The first videoconferencing system was introduced by PictureTel in March 1986 and cost $150,000 per endpoint (MacArthur 2002, p. 58). Fifteen years later, prices have dropped as low as $600 for a full-feature unit (speakers, microphone and dedicated video processor hooked up to a computer and monitor and it has become accessible to even small business. Webcam sell for less than $100, though the video quality is lackluster. The big difference in the equipment evolution is that the third- and fourth generation systems produce good quality video and audio, are reliable and permit centralized management. The key ingredient in this improvement is the codec, which is a processor for video encoding and decoding. A codec can also be software-driven, drawing on the computing power of the PC (Perey 2000, p. 49).
Modern videoconferencing is based on three technological standards under the International Telecommunications Union (ITU):
- H.320: Based on narrow-band visual telephone systems and terminal equipment, this technology standard address videoconferencing over circuit switched services like ISDN or Switched-56. It was ratified in 1990. It has been the industry mainstay for the past decade (Gringonis 2001, p. 60). Currently, about 85 percent of all installed systems are work over ISDN (Hooper 2002, p. 44).
- H.323: The standards encompass audio, video and data communications across packet-based networks, including Ethernet, Fast Ethernet, Token Ring and ATM that can be interconnected by various private and public Wide Area Networks (WAN) - ISDN, V.35, E1/T1, Frame Relay, ATM and others. It was ratified in 1996.
- T.120: These standards cover the document conferencing and application sharing (sometimes called data conferencing) portion of a multimedia teleconference and were originally ratified in 1995. The recommendations specify how to efficiently and reliably distribute files and graphical information in real-time during a multipoint multimedia meeting. See the International Multimedia Telecommunications Consortium (IMTC) site for more information.
Videoconferencing systems will continue to rely on ISDN for a few years more because IP has been unable to offer the reliability and quality of service to as many locations as ISDN can on a consistent basis. However, ISDN's limitations (spotty availability across the country, service interruptions, difficult management) are holding back greater use of videoconferencing and pushing usage toward IP networks. (MacArthur 2001, p. 47)
The Big Shift
The big change in the past five years has been the shift from using ISDN to IP -- that is, from videoconferencing over circuit-switched telephone networks to packet-switched networks that use Internet Protocol. Sales of dual mode videoconferencing systems had jumped to the forefront, capturing 89 percent of the market for new equipment. IP conferencing is virtually free because it flows over the same LAN/WAN connections that are used to send data. A company can piggyback a videoconferencing network on top of its existing data network. For instance, ISDN costs for a 384 Kbps conferencing link can be up to $135 per hour, plus the cost of a ISND call bridging service. Increase the reach to 10 different locations, and the cost rises to $1350 per hour (Fritz 2001, p.48).
Fritz (pp. 49-52) points out, however, that there are still major hurdles that must be overcome for IP technology to reach its full potential:
- Endpoints: not all endpoints are IP-capable, and legacy hardware complicates the process. However, practically all new products provide for interoperability between IP and ISDN compatibility.
- Gateways/Multipoint Conferencing Units (MCU): multipoint conferencing (usually more than four endpoints) requires a MCU to manage the traffic. A MCU can cost about $40,000 so a network administrator has to justify the investment with large volume of videoconferencing usage. A cheaper option is to go to an outside source for bridging services.
- Gatekeepers: these servers route traffic through to the right IP address. They also determine if there is sufficient bandwidth on the network to carry the traffic efficiently.
- Quality of Service: QoS is the biggest problem for IP video. The Internet is based on bursts of data packets that may take different routes and arrive at their destinations at different times. Video requires a continuous stream of bits arriving in sequence. Within a single network, it is easy to control quality because a network administrator can use technologies like Cisco's Weighted Fair Queuing or DiffServ that allow routers to prioritize video traffic. Once routed into the public Internet, however, control is lost. One way around this problem is to use a video application service provider (ASP) that has a private network, including backbone, and can guarantee quality. However, if the video ASP does not have a point of presence where the user wants to set up videoconferencing, he/she is out of luck, and must fall back on the public Internet.
- Firewalls/Network Address Translation (NAT): Both firewalls and NAT devices can block incoming calls because they don't understand video. A network administrator can work around these problems, for instance, by setting up the MCU in a DMZ or using a Virtual Private Network (VPN) to tunnel through the firewall. In addition, the use of a VPN can help lock in a minimum amount of bandwidth over the Internet. Newer router models are improving their H.323-awareness abilities, but the eventual solution will come with IP 6.
- Management: large-scale use of videoconferencing needs tools that allow administrators to control endpoints, gateways, gatekeepers, device settings, and address directories. For instance, a more intelligent use of bandwidth would use IP multicasting and streaming media systems to broadcast to multiple many remote viewers.
Perey (2000a, p.56) points out that heavy use of videoconferencing over IP networks will require administrators to adjust their networks for real-time traffic. She underscores three approaches: reworking the network topology to provide ample bandwidth, implementing QoS standards on LANs and WANs, and taking measures to shape traffic, if and when congestion occurs.
Boost from Voice and the Browser
A growing trend that will pull videoconferencing towards wider usage is voice over IP (VoIP). "Companies that are implementing VoIP are solving a lot of their infrastructure problems as they go and thus they are breaking new ground and doing the pioneering work necessary to make the full-scale delivery of quality video possible over their data networks," says Fritz (p. 50). In addition, the cost savings that IP telephony provide can also be mirrored by savings on the video side. A shift to a video ASP from ISDN can reduce carrier costs by 50%, for instance.
Another contributing factor is that web conferencing offers another area in which companies gain online experience. As the Internet has become ubiquitous and web browsers are on practically every computer, web conferencing filled a gap between e-mail/instant messaging and full-fledged videoconferencing. It can even work over a 56 kbps modem connection. Most of these applications are compatible with Microsoft Office and streaming audio-video plug-ins, like Media Player, RealPlayer and QuickTime. However, although some platforms provide for video, it is not two-way as with videoconferencing, though participants can exchange text messages or plug in by using a phone. Some of the big players in web conferencing are WebEx, PlaceWare, Centra and Eloquent. (Boeri 2002, p. 49)
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