In the preceding chapters, you have seen how you can set up your corporate intranet to facilitate business communications using e-mail, chat, and Internet phones. By now, you might be wondering whether you need to take the leap to support video-conferencing applications as well. Video-conferencing, although certainly not an essential part of every intranet, can offer a practical means of providing cost-effective, in-person communications among employees and customers. To evaluate the pros and cons of video-conferencing over the Internet and intranet, you will want to consider bandwidth constraints, hardware and software requirements on the server and client sides, and the cost incurred for each desktop you want to equip with video-conferencing capabilities. The information provided in this chapter is intended to help you decide whether video-conferencing is a realistic, practical communications tool for your corporate intranet.
Once symbolic of the space age, communicating both voice and video in real time has become a realistic option for many clients. Whereas early "room based" models required participants to gather in a conference room equipped with cameras and look at monitors displaying similar rooms at remote sites, the desktop model works more like a telephone call, allowing participants to call up the other participants from their own PCs. Vendors, such as PictureTel and Intel, introduced desktop video-conferencing systems that use regular phone lines about five years ago; however, these proprietary systems can be extremely cost-prohibitive to set up and maintain. By comparison, the use of TCP/IP over Ethernet LANs provides a favorable environment for applications that require the simultaneous transmission of audio and video. The intranet environment offers more bandwidth than solutions that run over regular phone lines. Unlike with the Internet, the network operator of a corporate intranet can control the type of connection between desktops using video-conferencing applications, which makes performance levels more manageable and predictable.
This wave of Internet communications began to attract attention when Cornell University released the CU-SeeMe program as freeware for the Macintosh in 1993. The program allows users to conduct point-to-point communications, group conferencing, and broadcasting with audio and video over the Internet. Since its release, more than a half million individual users have downloaded CU-SeeMe for recreational and educational purposes. More recently, commercialized versions of CU-SeeMe, such as the enhanced version offered by a company called White Pine, are making it a viable means of business communication. Now, the corporate intranet provides a fertile territory for real-world business applications of video-conferencing over both local and wide area networks.
The basic parts of a video-conferencing system include video, audio, a whiteboard, a running application, and encoding software. Video requires a camera and video capture board; audio requires a microphone and speakers or headphones. Almost all commercial software offers a "whiteboard" function to display graphs, images, text, and documents, or to write on shared applications. Finally, software encodes and compresses the signal and then transmits the signal to remote sites.
The key limiting factor in video-conferencing is bandwidth consumption. Bandwidth is the amount of information per unit of time that a particular transmission medium can handle. Sending audio and video through any communications channel requires an enormous amount of bandwidth. To avoid a bottleneck, system administrators need to consider carefully the issues raised later in this chapter that relate to compression standards, server hardware and software requirements, and client packages.
Video-conferences facilitate cost-effective face-to-face contact among employees, clients, and other business contacts who might be scattered throughout the world, as shown in Figure 33.1. The early adopters of video-conferencing technologies that run over the Internet include professionals in the education and scientific communities, who in 1993 and 1994 began discovering the opportunity for conducting in-person communications via video-conferencing applications.
Figure 33.1: A multicast video-conference.
For the corporate intranet, the applications for video-conferencing include connecting distributed work teams, enabling learning or training from remote locations, and providing entertainment broadcasts. Currently, corporate usage of TCP/IP-based video-conferencing is progressing from testing among small groups and pilot projects into an established communication medium for select groups of users. Widespread adoption of desktop video-conferencing is an increasingly viable option as the latest browsers with integrated video and audio capabilities become available. Currently, Netscape is beta testing its Atlas browser, which includes full support of the LiveMedia framework, which integrates real-time audio and video into the browser itself.
Following are a few examples of how companies across different industries are using desktop video-conferencing to reduce travel costs, facilitate quick communication of time-sensitive information, and provide enhanced customer service.
Sales and Marketing
Ameritech uses a video-conferencing application to communicate between sales offices and headquarters. This lets the company save on travel costs and improve the distribution of competitive information between the field and headquarters.
Technical Customer Service
SAP AMERICA uses video-conferencing to offer customers real-time, in-person support without the expense of on-site customer visits.
Portfolio Management
Chase Manhattan Bank has improved consultations between portfolio managers and institutional accounts by providing video-conferencing capabilities.
College Recruiting
At the Georgia Tech Institute of Technology, video-conferencing lets employers screen candidates in real time without incurring travel expenses.
Medical Applications
A radiological services company is lowering the costs of patient consultations by using desktop video-conferencing. Medical specialists in remote locations have immediate access to X rays and surgery videotape.
Real Estate Applications
Loan officers at real estate agencies use video-conferencing to contact home buyers for loan qualification and processing.
Video-conferencing applications use the UDP (User Datagram Protocol) for sending streams of information, rather than packets of information. This protocol passes the responsibility of ensuring packet reliability to the application.
Therefore, the protocol is better able to manage the dynamic data feeds required for video-conferencing. The UDP Protocol also ensures that new information has precedence over confirming what was already sent; instead of checking to see that every packet has been received, the protocol places a higher priority on maintaining a steady flow of new information. This method of operation is important because lost packets of video will not interrupt the user's understanding of the information being transmitted in the way that lost packets of text or audio will. In the case of video, it is crucial to keep new information flowing and less important to allocate resources for error-checking applications.
The UDP Protocol made possible the development of a video server, called a reflector, that intelligently routes multiple streams of data during a conference. Reflectors act as intelligent broadcast stations for the participants in group video-conferences. They improve bandwidth capabilities by transmitting streams of managed video and audio broadcasting. By chaining reflectors together in a distributed network, companies can improve scalability and expand coverage by supporting different networking setups. The network operator is able both to adjust a video-conferencing setup as the number of users grows and to accommodate a network that uses several different platforms. Reflectors also can serve as effective agents for bandwidth-management, as discussed later.
To understand what a difference reflectors make in facilitating video-conferencing over the Internet, it is helpful to consider how group conferences operate without reflectors. Some products use the unicast method, whereby individual data streams are transmitted, and dedicated bandwidth is set aside for each participant in the conference. This method consumes excessive bandwidth because multiple copies of the video and audio data stream are transmitted to every attendee.
Alternative products use the Internet's MBONE (Internet Multicast Backbone) capabilities designed for multicast techniques. Multicasting involves sending information from one computer to a group of computers that are not necessarily on the same network. The earliest MBONE-based conferences began in the late 1980s, and by 1994, the system had grown to include more than 1,200 individual networks. Currently, more than 2,000 sites support MBONE, and the number continues to grow rapidly. Unfortunately, these products lack some essential broadcasting features-for example, they transmit data only when people are watching. Network administrators who need to minimize unnecessary bandwidth consumption will not want a video-conferencing application to transmit data when no one is watching. Additionally, these products require dedicated routers and software configured to take advantage of multicasting. Considerable effort is required to configure an MBONE router (mrouter), but after it is installed, relatively little daily maintenance is involved.
For system administrators, the basic dilemma in adding manageable video-conferencing to an intranet is balancing the speed and quality of video and sound with taxing bandwidth requirements. Although it is extremely difficult to measure the bandwidth needed to transmit audio and video on the Internet, the amount is recognized as being high. To alleviate bandwidth constraints, network administrators can increase bandwidth or improve compression methods.
The higher bandwidth communications channels, such as ISDN (Integrated Switched Digital Network), Ethernet, Fast Ethernet, or ATM (Asynchronous Transfer Mode) are ideal for supporting video-conferencing. The most important consideration is selecting a circuit switch setup, which will accommodate the continuous stream of data necessary for video-conferencing applications.
The way in which specific compression algorithms are actually performed should be of little interest to the intranet architect. What is crucial, however, is understanding how well the compression performs, how well it inter-operates with products from other companies, and how well it handles operating on a heavily loaded network. Most products available today use the H.261 compression standard for video. When combined with a standard audio compression algorithm, the two components form the H.320 standard. These standards, originally established for video telephones, are capable of supporting two frame sizes, neither of which takes up an entire screen. QCIF is the standard frame size, with 1765144 pixels, and CIF is a larger frame size yielding 3525288 pixels. The number of pictures shown per second, called the frame rate, varies depending on CPU speed and bandwidth. For example, bandwidths of about 128 Kbps (video) and 64 Kbps (audio) could result in about five frames per second. This rate is adequate for video-conferencing, but not equivalent to a VCR-quality playback rate of 30 frames per bandwidth for audio. This might be desirable because audio is transmitted on the Internet in packets, which have to be synchronized with the stream of video. A delay, however, usually results in lost packets, which is more problematic than sacrificing some of the video quality to preserve the quality of the speech.
System administrators interested in supporting video-conferencing over the Internet without the compromise of excessive bandwidth have several tools at their disposal. As mentioned previously, reflectors also can serve as effective managers of bandwidth. The servers from White Pine are able to adjust transmission rates of individual users on-the-fly during times of heavy network traffic. Also, reflectors can manage data for supporting applications such as whiteboards or chat windows. System administrators can set minimum transmission rates that will adjust to different speeds of connections to the network. Thus, bandwidth can be optimized for ISDN, ATM, or modem lines. The bandwidth management capabilities of reflectors are essential to Internet Service Providers that have to balance the requirements of their non-video-conferencing network with the bandwidth consumed by their video-conferencing users during peak times of the day.
Finally, system administrators should turn some of the responsibility for bandwidth management over to individual users themselves. Courteous desktop video-conferencing etiquette alleviates bandwidth crises significantly. Users should not leave video windows transmitting empty offices or conference rooms open. Also, users should be reminded to conserve bandwidth by avoiding unnecessary transmissions.
Various packages of hardware and software for video-conferencing
over the Internet are available from vendors including White Pine,
Automated Management Systems, Connetix, Insoft (Netscape), and
BBN Systems and Technologies. Table 33.1 summarizes many of these
products.
| Product | Company | Web | ||||||
| CU-SeeMe | White Pine | www.cu-seeme.com | ||||||
| CoolView* | Netscape (Insoft) | www.home.netscape.com or www.insoft.com | ||||||
| Picture-Window | BBN | www.bbn.com | ||||||
| CineVideo | Cinecom | www.cinecom.com | ||||||
| FreeVue | N/A | www.freevue.com | ||||||
| Video Phone | VIC Hi-Tech | www.connectix.com | ||||||
| *Will be bundled with Netscape Navigator. | ||||||||
White Pine offers its enhanced CU-SeeMe software for Windows, Windows 95, Macintosh, and Power Macintosh. Users can have up to eight participant windows and an unlimited number for audio and talk windows. The caller ID feature is a message alert box for incoming connections. It provides a whiteboard for collaboration during conferences and supports multiple users. White Pine offers Mosaic browser support for direct launch of CU-SeeMe from its Web page. It also allows for selectable audio compression algorithms with 100 ms and 50 ms sampling settings: 2.4 Kbps and 8.5 Kbps audio codecs to support 14.4 Kbps and 28.8 Kbps modem connections; and 16 Kbps and 32 Kbps codecs for higher bandwidth connections. Additional features include support of 24-bit true color and 4-bit gray scale; a phone book for saving, adding, and editing participant addresses and reflector sites; standard and high-resolution settings for video compression; and password, caller ID, and other conference and inbound call security. Installation is relatively simple and user-friendly with TCP/IP network software.
Another vendor, Connectix, initially produced only computer-mounted cameras for the Mac and PCs; however, it now bundles video-conferencing software with the cameras. Insoft (now owned by Netscape) offers CoolTalk and CoolView software products designed for Windows 95. These products have been designed right into that Netscape browser so that users do not need to leave the browser to use the video-conferencing client. The disadvantage of using these products is that all participants in the call must have the company's software installed. At this time, Insoft has no plans to release similar products for the Mac.
BBN Systems and Technologies recently released PictureWindow, a software package that allows workstation users to hold video conferences over existing IP networks. The product uses Sun's VideoPix frame-capture board and a video camera to bring video-conferencing to a color or gray-scale SPARCstation. The software retails for about $495 per workstation; a PictureWindow package, including software, a frame grabber, and a color camera, is available for $1,495. For the first release, the company offers a receive-only version of the software at no cost. The software can be used in either point-to-point or multicast mode. The multicast option allows for an unlimited number of receive-only stations, which could be ideal for some training courses or company-wide presentations. The frame rate is generally about three to six frames per second, depending on the system and the network. The product functions best with network paths of at least 256 Kbps, but it can be used with bandwidths as low as 56 Kbps by accepting a lower frame rate and quality.
In addition to these vendors, some of the leaders in the market for desktop video-conferencing over regular phone lines, for example Intel and PictureTel, might offer products for the Internet soon. As these bigger players bring products to market, the prices for video-conferencing applications should come down significantly.
Additional factors to consider in selecting a client package include security demands for the video-conferences your employees will hold, reliability of product support, and the quality of broadcasting you will require.
Do you need a video-conferencing component built into your intranet? Probably not; however, it could save considerable time and money to provide for video-conferencing while you are planning your intranet strategy. As the technology improves, you might decide that video-conferencing is an essential tool, and you won't want to change your entire hardware setup to support it. Fortunately, the latest generation of browsers and server software is bundling support of live media. Netscape Navigator already provides its LiveMedia structure to send audio and video from within the browser.
If you have decided to implement video-conferencing over your corporate intranet, you should consider these initial steps for setting it up. First, you should start with a very small test group. Try beginning with no more than 10 clients for the first pilot project. Second, refer to the table provided to get an idea of the products that work on PCs and Macs. Third, be sure that each pilot desktop has the following components:
Minimum System Requirements for Macintosh
System 7.x with 8 MB (16 MB recommended)
Connectix QuickCam or Video card with Video Camera
Microphone and speaker
Minimum System Requirements for Windows
486DX/66 8 MB RAM
Connectix QuickCam with serial port digitizer
Microphone and Speaker
Sound card with 8-bit sound (SoundBlaster 16 recommended)
8-bit video with 640-480 resolution
Install the client software on each system, and test the software configuration by using one of the public reflectors. When connecting to a public reflector, keep in mind that most reflectors do not allow connections at rates greater than 80 Kbps.
After the clients are configured and tested, it's time to tackle the server side of the operation. CU-SeeMe's reflector software is written in C code and can be compiled and installed on various UNIX platforms, including, among others, Solaris, SGI, BSD, FreeBSD, and OSF-1. This software is also available for Windows NT and Windows 95. The reflector can be configured quickly in UNICAST mode, which allows for point-to-point conferencing. More time and experience, however, are required to set up the reflector in MULTICAST mode.
Although the video phone has been around for many years, only recently has this method of communication been seriously entertained by system administrators for business communications. Proponents of video-conferencing over the Internet think that it could ultimately replace the telephone as the primary means of business communication; however, compression and bandwidth issues are still stumbling blocks for successful implementation of the technology in corporate intranets. Video-conferencing technologies are likely to improve along the same timeline as technologies for increasing bandwidth are developed and implemented.
Is video-conferencing a viable business communication tool that should be included in the corporate intranet? The answer depends on the specific goals and configuration of individual networks. Video-conferencing affords corporations the sophistication of in-person communications in a model that can be incorporated into a cost-effective intranet strategy; however, bandwidth concerns still create challenges for the system administrator.
As practical solutions to these issues are developed, video-conferencing over the Internet might ultimately become a de facto standard for business communications. In the meantime, most businesses will continue to rely on e-mail, chat, and even Internet phones to handle the bulk of communications traffic over their intranets.