Library items tagged: Videoconferencing

Local area networks of any significant size, which almost certainly encompasses all those at educational organisations, are complex and unpredictable systems. The traffic flows produced within these networks, and the interactions between different flows within network components such as switches, are highly complex. Classifying, policing and priority queuing allow the network administrator some control over how these flows transit the network, and – crucially for voice and video traffic – allow time-critical traffic to have priority over other, less time-sensitive traffic.

This section examines the role of physical separation in the provision of reliable and secure links for real-time traffic. In many cases equipment can be directly connected together without being also plugged into the campus LAN directly. This can be especially beneficial when equipment is dedicated to a task – such as videoconferencing equipment – that operates stand-alone, i.e. is not part of a desktop PC used for normal network access/applications.

This chapter aims to describe in some detail the demands that videoconferencing traffic places on the network, along with the metrics that can be used to predict – to a certain extent – the behaviour of a videoconference. Readers who may be less interested in the specifics of ‘Why is this important?’, and would like to move swiftly on to ‘What should I look at and do?’ are welcome to skip this section completely and move along to chapter 3.

Room based systems generally use large picture and / or data monitors while lecture theatres will have projection systems. The CODEC (coder / decoder) will connect to these monitors either through a composite, an S-Video interface, or a SCART connector. Data displays for local and remote sites will normally use a VGA or DVI connection to the display device. Some monitors and most data projectors can handle both video and data signals.