In contrast, a VideoServer Encounter NetServer, configured to manage up to 24 simultaneous H.323 calls that connect over an enterprise TCP/IP network, costs just $64,490 (including installation and one year of maintenance). Further savings may be had if the cost of upgrading the enterprise network to accommodate multimedia is less than your current ISDN circuit lease and operating costs. But will the VideoServer Encounter handle H.323 as well as the old PictureTel/VideoServer handled H.320?

We tested five native H.323 MCUs--server-based VideoServer Encounter NetServer 1.2.1, White Pine Software MeetingPoint 4.0, and PictureTel 330 NetConference MultiPoint Video Server Software; and rack-mounted Lucent Technologies MultiMedia Communications Exchange (MMCX) and RadVision MCU-323--at the University of Wisconsin.

For these tests, we operated out of the new Pyle Center, a state-of-the-art conference management facility run by the University of Wisconsin-Extension's Instructional Communications System. And, we linked over the Internet to the Communications Systems Center in the School of Electrical and Computer Engineering at Georgia Institute of Technology.

In our tests, VideoServer Encounter NetServer, our Editor's Choice, had a slight edge in the server-based MCU category, primarily because it uses hardware assists to boost performance and add versatility. It is the only system we tested that supports a mixture of audio/video codec algorithms in the same conference, a capability that makes it significantly more expensive than software-only server-based solutions. The latter are well-designed for small workgroups or widespread training applications for which performance is a not an issue. The bottom line: Now you've got choices. Any one of these systems could suit your needs, depending on the situation.

The same is true in the rack-mounted MCU category. Our Editor's Choice winner, Lucent's MMCX, edged out the RadVision MCU-323 primarily because it offered better browser support for conference management and monitoring; the MCU-323 isn't due for a major new software release until early next year. Still, the MCU-323 may be a better choice for an organization that already has invested in RadVision's LIU-323 H.320 gateway product.

We restricted our tests to native H.323 MCUs--thereby excluding the Compunetix Virtuoso, a native H.320 bridge that accommodates H.323 interfaces. We also had to eliminate FVC.COM, which had no H.323 MCU shipping at test time, and VCON, which provides endpoint software designed for streaming and interactive videoconferencing, but no native H.323 MCU.

We also tested the latest hardware/software releases on a variety of endpoints: Intel Corp.'s ProShare 500 version 5.1 with TeamStation version 4.01 update 6, Microsoft Corp.'s NetMeeting 3.01, Polycom ViewStation beta 5.0, Sorenson Vision Envision version 2.01, and Zydacron Z350 V2.10. The full report of these tests is available at www.networkcomputing.com/1018/1018f3side3.html.

You've Come a Long Way, Baby
Overall, we feel H.323 is nearly ready for prime time. Most of the manufacturers participate regularly in closed interoperability meetings. (There's one later this month in Hawaii, for example.) Known problems that we report here are under active investigation, and are likely to be resolved in new software releases early next year. By then, most systems will comply with H.323 version 2. We're confident that enterprise managers can begin to move from a "wait-and-see" stance to "buy-and-try" for pilot projects and feasibility studies.

Most videoconferencing manufacturers already have developed solid implementations of the audio and video codec algorithms underlying H.323. It's the wiggle room in call setup capabilities exchange, and registration with gatekeepers, that can drive you to distraction, especially when you're setting up MCUs with a variety of endpoints.

Yes, H.323 is a standard. But it is also an umbrella specification that allows options (see "The Algorithm and Protocol Suites," page 88). For H.323 to work well, you must understand fully and perhaps influence which protocols are in play during automatic call setup negotiations (especially the audio algorithms, which are crucial to the perceived quality of a videoconference).