VideoNetworking.com

With the popularity of IP-based videoconferencing systems, we're again hearing the videoconferencing explosion is upon us.

Between ironing out new standards and overcoming bandwidth limitations, it will be many more years before face mail is a fact of life. But developers can begin to implement the technology for intranet collaboration, and the groundwork is being laid for new services such as video chat and live sales assistance for Web shoppers.

IP could be just the boost this industry needs. While sales are brisk in the fast-growing distance-learning market, the corporate world remains ambivalent about videoconferencing. Group systems such as PictureTel's Concorde, used to reduce travel budgets by enabling meetings between branch offices and major clients, are too expensive for most budgets.

Now that the ITU (International Telecommunications Union) has approved version 2 of the H.323 standard for IP-based videoconferencing, the transition to IP is in full swing. Delivering real-time video over intranets is cheaper than using ISDN. And unlike the ISDN-compatible H.320 standard, which requires expensive multiplexing to move beyond 128Kbps, H.323 automatically scales to the fastest networks. There's strong appeal in integrating videoconferencing with core IP services such as Web serving, groupware, and IP multicasting.

Internet videoconferencing has been dominated by White Pine Software's CU-SeeMe, but the widespread bundling of NetMeeting has increased its visibility. Though most use NetMeeting just for document conferencing, and those with a netcam usually lose patience with the low-quality video, the sheer numbers have boosted the technology. Intel has incorporated H.323 in its Video Phone, White Pine has a server that supports any H.323 client, and PictureTel recently introduced an H.323-compliant version of its LiveLAN client.

The chief obstacle for H.323 is that networks provide a far less hospitable environment than a secured ISDN connection, and latency continues to be a problem. You need a minimum of switched 10Mbps Ethernet, and even with switched 100Mbps there may not be enough guaranteed bandwidth on a busy network. Version 2 of H.323 adds support for ATM, which offers the quality-of-service guarantees that videoconferencing craves. But since ATM is a rarity in the LAN world, most networks will depend on version 2's support for RSVP (Resource Reservation Protocol), to reserve bandwidth.

As an alternative to using in-premise IP networks for videoconferencing, Safari Technologies has developed a parallel network solution that uses the unused pair of wires common with most Ethernet infrastructurers. To the delight of data managers, this method of desktop or room video switching leaves the data stream untouched while distributing a very high-quality picture. This does not however, solve the bandwidth problems when the videoconference leaves the building.

Since H.323 is scalable, it can also handle faster connections such as XDSL; but even with 768Kbps each way, videoconferencing on the public Internet can be an adventure unless you're on a virtual private network. Concentric Network has introduced a new VPN that lets corporate users ride over an ATM backbone to other major metropolitan areas. With telecom companies like Qwest and Worldcom also building fiber-optic superhighways, coast-to-coast IP videoconferencing may soon be within the reach of many companies.

Until these pipelines arrive en masse, however, ISDN will play a major role. Version 2 of H.323 defines H.323-to-H.320 gateways, so that products such as PictureTel's LiveGateway can bring IP and ISDN callers together. It took several years until true interoperability between H.320 systems was a given, so expect a similar lag for H.323. In a sense, the videoconferencing industry is starting over from scratch. With IP, at least it's now on the right track.