Videoconferencing

A money- and timesaving alternative to travel

We can't conduct business without meetings. But with travel budgets tightening, bringing remote workgroups and customers together is increasingly difficult. Videoconferencing helps solve that problem by letting distant parties collaborate without travel. In fact, videoconferencing can make employees more efficient even when all meeting participants are on the same campus.

Videoconferencing systems are designed for either desktop or conference room use. Desktop systems let an individual meet with another individual or group in another location. Conference room systems provide features that let a group in one location videoconference with one or more individuals or groups in other locations. Desktop systems are based on the International Telecommunication Union (ITU) H.323 LAN and Internet videoconferencing standard. You can configure conference room systems to support the ITU H.320 standard for videoconferencing over ISDN lines, the H.323 standard, or both. Both standards encompass several audio and video compression-decompression (codec) standards, as well as the ITU T.120 data-conferencing standard, which allows for file sharing, whiteboarding, and file transfer.

Starting at the Desktop
Desktop videoconferencing products are simple and inexpensive to implement. Microsoft NetMeeting, which has been included with Windows OSs for some time, is the least expensive approach to videoconferencing. NetMeeting lets two parties see each other and converse, but the program's application-sharing, whiteboard, and file transfer features are what make videoconferencing a viable alternative to in-person meetings. To share NetMeeting's video and audio among more than two parties, you must buy Microsoft Exchange 2000 Conferencing Server (ECS) or a separate Multipoint Control Unit (MCU).

For a better desktop videoconferencing experience (although at a higher price), take a look at Winnov's Videum 1000 and Videum MXC Color Camera ($419 direct), PictureTel 550 Videoconferencing ($1200 list), and Polycom's ViaVideo ($599 list) H.323- and T.120-based desktop videoconferencing products, all of which work with NetMeeting. (For vendor information, see "Contact the Vendors.") The Videum 1000 and PictureTel 550 provide PCI video/audio capture cards and cameras that eliminate the need for a USB port and thus aren't limited by the port's 12Mbps transfer rate, promising better video quality than a USB-based WebCam. Both products' video capture boards also provide dedicated sound circuitry, which should improve audio and video synchronization compared with the separate video and sound circuitry provided in most PCs. By relieving the PC's CPU of video compression and decompression responsibilities, the PictureTel 550's digital signal processor (DSP) promises more efficient video processing and lets the CPU focus on document collaboration tasks.

The ViaVideo takes a different approach, combining a camera, a microphone, a sound card, and compression hardware in the camera housing, which plugs into the PC's USB port. A DSP compresses the audio and video before transferring it to the PC, yielding better video quality than a WebCam. Like the Videum 1000 and PictureTel 550, the ViaVideo has onboard sound circuitry for better audio/video synchronization than most WebCam-based desktop videoconferencing solutions. The PictureTel 550 and ViaVideo have echo-cancellation circuitry, which eliminates the need for a headset.

Windows XP and its conferencing component, Windows Messenger, can also provide a good desktop videoconferencing experience, thanks to the OS's echo-cancellation capabilities and support for a new high-fidelity audio codec. (For more information about Windows Messenger, see the sidebar "Conferencing, Windows XP—Style.") With a desktop solution in place, a user can use Exchange 2000 Server's instant messaging capabilities or Microsoft .NET Messenger Service (formerly MSN Messenger Service) to determine whether another user is available and to invite that user to participate in a videoconference.

Room Conferencing Systems
Conference room systems are typically designed either for small groups of up to 10 people or for larger meetings of up to 30 people. Most systems intended for larger groups (aka boardroom systems) use cameras with a wider field of view and let you connect multiple cameras and microphones.

Before purchasing a conference room system, you need to consider factors such as how many simultaneous conferences you'll need to be able to support and how many remote conference room and desktop videoconferencing endpoints will need to join each conference. Think about how many participants will be involved in videoconferences and the participants' special needs (e.g., high-quality video and audio, an electronic whiteboard, playback from a DVD player or a VCR, multiple cameras and microphones for large groups, document or object cameras for sending images of documents or models). Also consider whether your network has the necessary bandwidth. When you look at solutions, ask about vendors' document sharing and collaboration features and the remote management and diagnostic software each product provides.

Videoconferencing always involves a trade-off between image quality and network bandwidth. A 128Kbps transmission rate, which typically delivers 15 frames per second of noninterlaced video, might be adequate for internal meetings, but business-quality video typically calls for 30 frames per second at a 384Kbps transmission rate. Generally speaking, all but the lowest-priced conference room systems can provide business-quality video by using either ISDN or Ethernet network interfaces.

Some specialized environments, such as telemedicine (i.e., health care provided over a distance through telecommunications technology), demand extremely high-quality video. Some systems, such as Polycom's ViewStation FX (starting at about $15,000) and the PictureTel 900 Series (starting at about $11,000), can improve image quality through the use of 60-field interlaced video, effectively doubling the vertical resolution and providing more fluid motion. This level of video can require transmission rates as high as 2Mbps.

Room videoconferencing systems use the ITU G.722 or G.722.1 audio codec, both of which employ a 16KHz sampling rate. These codecs deliver adequate sound quality for business conversations. If your applications demand the best audio quality possible, check out the PictureTel 600 Series (for groups of as many as 10 people; prices start at about $7000) and the PictureTel 900 Series. These systems use PictureTel's patented Siren-14 audio algorithm, which offers a 32KHz sampling rate that should provide better sound fidelity than products that rely on the G.722 or G.722.1 codec.

Different room-based videoconferencing systems use different ways of sharing electronic files among conference participants. Many Windows-based conference room systems, such as VTEL's Galaxy series (which starts at about $10,000 and is configurable for small or large groups), the PictureTel 600 Series, and the PictureTel 900 Series, integrate the portions of NetMeeting that provide T.120-based file sharing to let remote participants view documents that reside on network servers or the videoconferencing system's hard disk. Videoconferencing systems that use proprietary OSs, such as Polycom's ViewStation models, typically rely on a dedicated LAN-connected PC running special software that sends document images to the local and remote meeting participants. Most vendors also offer optional scan converters that let presenters connect their laptop computers to the videoconferencing system so that local and remote participants can view their presentations.

Depending on your network's utilization, the expected frequency of videoconferences, the anticipated number of simultaneous meetings, and the bandwidth required for each meeting, you might opt to use ISDN service for your room conferencing system rather than tax your LAN with videoconferencing traffic. But even if you don't plan to route videoconferencing traffic over your LAN, including the Fast Ethernet interface on each system makes sense so that you can videoconference with sites that use H.323-based desktop and room conferencing systems, take advantage of the vendor's remote management software, and ease migration of your videoconferencing traffic to your LAN at some point in the future.

MCUs and Gateways
Most videoconferencing products are designed for point-to-point meetings. To videoconference with more than one other party requires adding an MCU. If participating endpoints use different ITU videoconferencing standards, you'll also need a videoconferencing gateway to convert between the various protocols.

MCUs are available in a range of capabilities and prices. Some room conferencing systems include basic MCU functionality. For example, Polycom's ViewStation FX and ViewStation MP (which starts at about $9000) enable videoconferencing between as many as four endpoints, and Sony's recently introduced PCS-6000IP boardroom system (starting at about $13,500) lets as many as six endpoints participate.

Dedicated MCUs usually provide more ports than built-in MCUs do and can handle several conferences at once, limited only by the number of ports. Many dedicated MCUs also include conference-scheduling software and let you choose between continuous-presence mode, which displays all remote parties' images, and selective display of the participant who's speaking.

The PictureTel 330 NetConference Multipoint Server supports all H.323-compliant desktop and conference room videoconferencing systems and is available in 8-port, 24-port, and 40-port configurations (prices start at about $13,000, $24,000, and $33,000, respectively). The PictureTel 330 is software that runs on Windows 2000 or Windows NT and includes Web-based applications that let the meeting organizer schedule videoconferences as well as create and manage virtual conference rooms.

If you plan to purchase many videoconferencing systems and need expandability and extra capacity, a multifunction platform solution makes sense. Some MCUs, such as the MGC-50 modular visual communications platform from Polycom's Accord Product Line, provide conversion between H.320 and H.323 protocols (eliminating the need for a dedicated videoconferencing gateway), rate-matching capabilities (so that all parties see high-quality video even if some participants are limited to a 128Kbps connection), and audio transcoding (which provides all participants high-quality audio even though some parties might be limited to a lower-fidelity audio codec). The MGC-50 costs about $59,950 when configured with 12 H.323 ports and 5 H.320 ports; you can upgrade the platform to support as many as 96 ports. Like the PictureTel 330, the MGC-50 includes a Web-based conference-scheduling application.

RADVISION's viaIP multifunction platform provides similar capabilities. You can purchase a viaIP chassis with four slots for expansion cards for about $6000, then configure it with viaIP MCU, viaIP Gateway, and viaIP Video Processor Server cards to provide the functionality and capacity you need. A viaIP MCU module costs about $40,000 for a 30-port card and about $100,000 for a 100-port card; a viaIP gwP-20 Gateway card with two PRI T1/E1 network interfaces costs approximately $40,000. The RADVISION OnLAN PRI Gateway with an E1/T1 PRI network interface, which has half of the capacity of the viaIP gwP-20 Gateway card, costs about $29,000. At press time, RADVISION hadn't set a price for its viaIP Video Processor Server card, which handles rate matching and transcoding functions.

If you plan to implement desktop videoconferencing by using just NetMeeting clients with WebCams, you might want to consider Microsoft's ECS, which provides MCU functionality along with conference-scheduling and resource-management capabilities. The product can reside on the same server as Exchange 2000 or on another server in the same domain (you can continue to run your mailbox servers on Exchange Server 5.5). Microsoft says that ECS can support multiple concurrent videoconferences with as many as 60 participants in each conference, depending on the server and network configuration. However, limited screen real estate makes 10 to 15 conference participants a more workable figure. Figure 1 shows ECS's Web-based client.

ECS includes a multicast ActiveX control that downloads to XP and Win2K clients (these OSs support IP multicast), minimizing the videoconference's network bandwidth requirements. For example, if each of the six participants that Figure 1 shows is running Win2K, the videoconference will use six audio/video streams (typically 60Kbps to 128Kbps each). If all six users run earlier versions of Windows or the network doesn't support multicast, the ECS H.323 bridge converts each unicast stream to a multicast stream. The bridge would also send to each participant a unicast stream of the participant who's speaking, for a total of 18 streams. If one of the six participants uses NT or Windows 9x, the conference would use only 8 audio/video streams. Clients running NT or Win9x see only their own video and that of the speaker.

ECS also comes with an ActiveX control that adds NetMeeting's data conferencing controls to ECS's Web-based client, as Figure 1 shows. ECS's management capabilities include the ability to limit the number of simultaneous conferences and the bandwidth allocated for each conference. ECS also provides failover and load-balancing capabilities to ensure high availability.

ECS costs $3999, and Client Access Licenses (CALs) cost $67 each. If you already have Exchange 2000 CALs, you don't need new ones for ECS. Compared with the cost of third-party MCU's, ECS can be an inexpensive way to bring multipoint desktop videoconferencing to your enterprise, depending on the number of CALs you need to purchase, whether you'll need to buy server hardware to run ECS, whether you choose to use third-party H.323 clients, and the maximum number of users who might need to join a videoconference.

Unfortunately, ECS doesn't support third-party H.323- or H.320-based desktop videoconferencing endpoints, so you'll need a dedicated MCU if you'll have a heterogeneous videoconferencing environment. ECS also lacks support for the Session Initiation Protocol (SIP) suite, meaning that XP users must use NetMeeting rather than the more advanced Windows Messenger conferencing product. At press time, Microsoft wouldn't comment on its plans to add SIP support to ECS.

Where Do We Go from Here?
The installed base of room conferencing systems uses primarily the H.320 ISDN videoconferencing standard, but LAN-based room videoconferencing systems are slowly gaining favor as H.323-based desktop videoconferencing becomes more popular. This trend should accelerate as the installed base of Exchange 2000 and ECS continues to grow. Ultimately, IP-based solutions should be less expensive because you won't need to pay the monthly and per-minute ISDN service charges. If you plan to use the Internet instead of leased lines for IP-based videoconferencing systems, talk to prospective vendors about their solutions to the Quality of Service (QoS) problems inherent to the Internet.

Microsoft is promoting SIP as a replacement for the H.323 standard to accommodate wireless products (for more information about SIP, see "Conferencing, Windows XP—Style"). However, most vendors of room-based systems, gateways, and MCUs are taking a wait-and-see attitude toward the new protocol. Even if wireless-device manufacturers adopt SIP, I expect that the H.323 and SIP standards will coexist for some time, just as H.320 and H.323 do now. If you plan to purchase a room-based or desktop videoconferencing product but are considering videoconferencing with wireless devices for the future, ask prospective vendors about their SIP upgrade path.