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About Videoconference

The videoconference is a form of interactive communication allowing two or more people who are in different places to get in touch in real time by using audio and image visualization. Activities such as meetings, courses, conferences, debates and speeches take place as if all the participants were together in the same place. This way, videoconference users can reduce the time spent moving around as well as travel expenses.

Lately, with the reduction in the price of the equipment that makes a videoconference possible and the improvement of the quality of the products offered, a growing interest in the videoconference service has been observed, both in the academic and in the commercial worlds.

In the academic world, Distance Learning has been the main responsible for this increase, together with researchers’ interest in sharing information with other geographically distant researchers. In the commercial world, this service is being very well accepted since it makes it possible to reduce the time spent by employees (hours, or even days depending on the distance) on trips to participate in internal company reunions or meetings with clients.

When we talk about videoconference over IP networks, most existing videoconference applications implement the specifications described in the H.323 recommendation of the ITU-T. However, there is also another standard, the SIP, which is less used over IP networks.

For a long time, a great deal of videoconference solutions were based on the H.320 recommendation of the ITU-T and used over ISDN networks. It happens because ISDN networks offer service guarantee, whereas in IP networks the best-effort law prevails; therefore, in an IP network we cannot guarantee that a videoconference will be successful. Fortunately, new technologies have appeared to solve the problem of the IP networks, and the videoconference service over those networks has grown. As for these technologies, we may cite the ones that grant band reservation and traffic priority, such as DiffServ.