Although it’s possible to drive video over a 33.6Kbps TCP/IP connection, an ISDN link or a T1 or T3 line will yield much better performance overall. At 33.6Kbps, expect a picture that’s little better than someone flashing photos in front of you–a slide show rather than a movie.
In addition to the fastest possible data pipe, you and your clients will need audiovisual equipment. At a minimum, each video participant must hook up a camera to his or her PC. Available alone or in videoconferencing kits, these cameras range in price from about $100 to $500; most plug into the system’s parallel port. Everyone will also need a microphone to speak into, and speakers or headphones to hear with.
As a rule of thumb, each client can expect to invest about $500 on hardware and software in order to enjoy Net videoconferencing. As the site master, you’ll also need a sufficiently powerful server or servers in place to handle the amount of multimedia traffic to be sent back and forth. Most servers can handle only a handful of videoconferencing users at a time.
There are a number of Web-enabled videoconferencing software packages available, ranging from CU-SeeMe and NetMeeting to Intel Corp.’s Internet Video Phone (connectedpc.com/cpc/videophone). NetMeeting is free with Microsoft Internet Explorer 4.0, but retail products usually provide more features and capabilities, which make them worth the extra money.
For instance, the $69-list CU-SeeMe with multipoint support not only allows several users to see one another and exchange audio and video, but lets them collaborate using a shared whiteboard. It even lets participants edit documents at the same time.
However, to support multipoint connections, you must usually prepare a site to act as a reflector. Using CU-SeeMe as our example, we’ll examine what it takes to get your site ready to process multipoint videoconferencing connections.
The H.323 Standard
Regardless of vendor, TCP/IP- and Ethernet-based videoconferencing products can communicate with one another and with ISDN (H.320) solutions thanks to the recently ratified H.323 standard. Before the International Telecommunications Union defined this standard suite, individual videoconferencing systems did not work and play well together–you had to use the same product at both ends and at the server.
At the core of the H.323 standard is a method for managing network latency, or the time it takes to send and acknowledge a packet. High-latency networks such as the Internet, where data packets must jump through many routers and subnets, have a tendency to wreak havoc on audio and video synchronization. To address this shortcoming, H.323’s Real-Time Transport Protocol (RTP) time-stamps and sequences packets and reduces delays.
H.323 also specifies the coding and decoding of video and audio signals, optimizing data for lower bit rates and low-bandwidth connections. H.323-compliant products just hit the market several months ago, and you should protect your investment by ensuring that the equipment you purchase complies with and lives up to the standard. Vendors are testing products now for interoperability, and Microsoft’s NetMeeting seems to be the early benchmark.
If you use a product like White Pine’s server for multipoint conferencing, you’ll have to install and configure a reflector, the piece of software that enables multiparty videoconferencing. Users link into the reflector, through which they’re able to establish and maintain multipoint connections to other clients. The reflector manages the connections, allows users to enable or disable connections, protects the site with a security system, and monitors client activity. (See Figure 2.)
The original White Pine Reflector package was delivered as Unix-ready C code, which needed to be installed, configured, and compiled. However, the latest version, Reflector 2.1, is a bit more politically correct. It does not require compiling, and it runs on Windows 95 or NT using a single executable file. Installation takes only a few minutes for Windows platforms, but expect to invest a significant amount of time to configure the software for a Unix system.
Once you’re up and running, you’ll oversee things from the Reflector Manager, a graphical console that lets you know what’s happening at your site. You can also use the Reflector Manager to configure multiple reflectors on local or remote servers. If you’re on a Unix site, you’ll need to run the Reflector Manager on a Windows 95 or NT client to monitor the Unix-based reflector.
As an option, White Pine Reflector can be configured to use multicast to send data to clients. Multicast requires less bandwidth than direct (point-to-point) connections, and is therefore ideal for a fully interactive group conference.
If you need to track usage for billing and accounting purposes, White Pine’s server provides a log file that can track individual participants and their time spent in the conference. For instance, you can use a credit-card number or club membership number to identify a user. This is helpful in corporate situations where you may disperse the cost of maintaining the reflector across several different departments that use videoconferencing. You can even set up a credit-card approval process though a CGI script or set it up to accept CyberCash for payment.
White Pine Reflector also provides an “observer mode,” allowing multiple observers to watch a single audio or video signal. This is useful for electronic presentations that are given company- or Internet-wide. Many can look and listen, but may not participate.
Should You Host a Conference?
Once you know how to implement videoconferencing from your Web site, the question is, should you? The answer depends on your expectations and needs. Obviously, a traditional conference-room videoconferencing system with dedicated bandwidth and infrastructure, and costing as much as $100,000 per site, will give you the best possible performance. But for most of us, this is not an option.
It’s more likely we’ll find ourselves choosing between an enterprise intranet-based solution and Internet-based solutions–or just trying to decide whether Net-based videoconferencing is worth the trouble. With an intranet setup, you’ll have dedicated bandwidth at your disposal, but you’re likely to get flamed by network managers once they see the amount of bandwidth you’re consuming.
Internet-based videoconferencing is the best solution for those who can live with compromise. Solid standards are in place, inexpensive and easy-to-install equipment is available, and it won’t consume valuable internal resources. But while the hardware, software, and H.323 standard are ready for prime time, the Internet’s packet-switched infrastructure falls short. Don’t expect a smooth, synchronized audiovisual experience over a data pipe of any speed.
The Internet Engineering Task Force (IETF) is working on yet another set of standards that may revolutionize the way the Net handles audio and video traffic, with the specific goal of addressing and solving many of the problems that limit the usability of today’s Internet videophones. But if you’re making your decision today, you’ll have to weigh the pros and cons.
CU-SeeMe lets Web clients view and communicate with one another to promote project collaboration, remote learning, or simply the exchange of information and ideas.