Virtual Conferencing: Read my lips

Philip Hunter casts a critical eye over the enabling technologies for Web-based collaborative work

Philip Hunter casts a critical eye over the enabling technologies for Web-based collaborative work

Take a drive down Highway 101 in San Jose, or indeed many other major US urban freeways, and you will see the future of virtual conferencing staring at you. Billboard after billboard proclaims the virtues of Web-based collaborative working. Although yet to escape from the doldrums in Europe, virtual conferencing is currently booming Stateside.

The three most prominent players, certainly to judge by billboard acreage, are WebEx, PlaceWare and Evoke Communications, which all offer the ability to conduct Powerpoint slideshows on the Web, with typically up to about five participants. Slides are uploaded to the co-ordinating Web site, such as, and the presenter can click to post them to all participants. You can also add slides on the fly during a presentation, including live Web pages as well as Powerpoint material, although participants cannot yet be given a tour of a Web site.

At present such packages offer only this relatively basic level of data collaboration, inferior to that offered by Microsoft's NetMeeting version 3, for example, and do not support videoconferencing. You might not think this very impressive, but such packages exemplify three key trends in conferencing, according to Steve Roe, marketing director of Ridgeway Systems, a UK developer of network-based telephony systems.

First, they highlight the growing demand for dataconferencing, with or without videoconferencing. Second, they indicate most users do not need the sophistication NetMeeting provides, such as the ability to collaborate on MS-Word documents; they just want to share slides and perhaps the odd diagram or Web page. Third, they offer IP-based conferencing via the Web, as opposed to over dialup services such as ISDN.

"Web-based collaborative working is really taking off in the US, and the traditional conferencing services suppliers are now very active in adding IP connectivity to their portfolio," said Roe. Even in the UK, BT, which dominates the market for any-to-any dialup video and audioconferencing services, is now planning to enhance them with integrated IP-based collaborative services. "BT will need to put its conferencing knowledge together with its IP knowledge," noted Roe.

The trend is towards the fusion of data and videoconferencing to yield an all-round collaborative working solution. According to Louise Cashin, vice-president for Europe, Middle East, India and Africa of conferencing specialist PictureTel, the world has moved beyond the age of talking heads to one of visual collaboration with all the assistance of a company's IT network. "It enables you to work more like you would face to face," she said.

Audioconferencing has been around for years and still has a sizable and stable if not rapidly growing market, involving dialup services with someone in charge of admitting participants and ensuring it runs smoothly. For the do-it-yourself types, the Web offers a medium to arrange audioconferencing services, allowing organisations to use the Internet to control their own sessions, pointing and clicking to admit participants.

This makes some neat features possible, such as the ability to have a private conversation within a session with one participant without the others being aware of it. The approach calls for co-ordination between the dialup telephony and the Internet. While this is an obvious technical overhead, it lays the ground for more comprehensive collaborative working over the Internet for data and ultimately video sharing as well.

Players who favour the dedicated approach such as PictureTel have their work cut out. In collaboration with network infrastructure companies like Cisco, firewall suppliers such as Checkpoint, and service providers like BT, they need to address the crucial issue of security and routeing. This is a large subject, but it is important to consider the potential threat to security posed by dataconferencing, especially where shared data and applications are involved.

Firewalls and access control systems are designed to restrict external access to approved sources, and to control activity within a network. Dataconferencing could breach such controls, because potentially it offers someone outside the organisation's firewall the ability to take control of a user's desktop and find ways of hacking into the network as well as capturing information from that PC.

For this reason, the T120 protocol, which looked as if it would become the de facto standard for dataconferencing, just as H323 was for IP-based videoconferencing, will probably be superseded by new standards more geared to the Web. T120 was designed more for point-to-point conferencing than a collaborative Web-based approach. If the Web is used as central point of reference and control, then the risks posed by giving external users direct access to internal PCs can be avoided.

This is another reason for betting on the success of the likes of PlaceWare and WebEx in the emerging multimedia conferencing market, even if they need to improve their video support and provide a wider range of functions. The industry as a whole also has some way to go in segregating generic higher level functions, such as control of the video stream, with low-level functions that are more hardware-specific, such as video compression, and packaging them separately.

Web-enabled conferencing

NTL recently brought out an example of the new Web-enabled virtual conferencing. A trial in its Surrey franchises involved voice, video and data via a telephone and Internet-enabled PC. The feasibility of adding good-quality video comes with the use of ADSL access circuits offering broadband bandwidth of several megabits per second downstream and typically 384Kbps or 512Kbps upstream.

A key feature is the use of standard dialup telephony rather than transmission of voice as IP packets integrated fully with the Internet. "This gets round the fact that voice over IP can be pretty poor quality. Until those problems are ironed out there will be a period where the phone network is a strong part of the conference solution," says Ridgeway's Roe, whose Portal Maker software underpins NTL's service.

But before long, voice will be transmitted over IP within the same stream as the data, making the conference session easier to manage and control. It will then be easier to bring users in and out of complete conference sessions at the click of a mouse.

Dedicated solutions

As far as pure videoconferencing is concerned, the industry has moved on since the days of large room-based systems linked by high-speed leased circuits. There would typically be two such systems, although with multiple participants in each room. Most of the technical developments focused on the quality of the audio with multiple speakers, and on video compression, to improve the resolution over a given bandwidth.

Then came smaller, roll-about systems capable of being taken into an office, followed by dialup videoconferencing over H320-based ISDN. At this time, around the mid 1990s, came the era of multipoint videoconferencing, allowing conferences with multiple participants to be set up within public services from the likes of BT.

Multipoint conferences could also be established within private enterprise networks, but only for participants within the company rather than any-to-any over a public dialup network. With multipoint conferencing, the technical focus shifted to control over the video stream. As people tend to look at the current speaker during a face-to-face meeting, it seemed natural to replicate this over a videoconference. But unlike at a face-to-face meeting, videoconferencers back then had no option of looking at other participants (perhaps to see how they were reacting to the speaker), so a 'continuous presence' feature was introduced, allowing each user to have video insets of, typically, four specified participants permanently onscreen, whether they are speaking or not. This can be combined on some systems with a fifth inset that switches to whoever is currently speaking.

Dedicated systems give superior audio/video quality, data integration and robustness. PictureTel's 900 series illustrates much of the recent progress that has been made, on top of the dual streaming of audio/video, and data. One useful feature for multiple participants at a single endpoint, which is the primary market for the system, is voice tracking, allowing the camera to focus on whoever is currently speaking; if two people are speaking simultaneously, for example the camera will pan out automatically to include both in the shot. However, PictureTel systems cost significantly more than PC-based alternatives.

PC-based hybrids

The bridge between dedicated audio and videoconferencing and Web-based dataconferencing is IP and Lan-based conferencing based on the H323 standard, leading on to the emerging era of Web-based conferencing. A distinction can also be made between PC-based systems in which the camera, audio equipment and other optional gear such as a projector are bolted on, and dedicated systems. Major suppliers support both options.

Another useful feature is the ability to attach a PC or laptop to the unit for transmitting both data and audio files to a conference session. A key point to consider when selecting a conference system is whether it can interoperate with other suppliers' end points.

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