  Video conferencing is a well-established area of communications, which have
been studied for decades. Recently this area has received a new impulse due to
significantly increased bandwidth of Local and Wide area networks, appearance
of low-priced video equipment and development of web based media technologies.
This paper presents the main techniques behind the modern IP-based
videoconferencing services, with a particular focus on codecs, network
protocols, architectures and standardization efforts. Questions of security and
topologies are also tackled. A description of a typical video conference
scenario is provided, demonstrating how the technologies, responsible for
different conference aspects, are working together. Traditional industrial
disposition as well as modern innovative approaches are both addressed. Current
industry trends are highlighted in respect to the topics, described in the
tutorial. Legacy analog/digital technologies, together with the gateways
between the traditional and the IP videoconferencing systems, are not
considered.
