Learn about Video Conferencing produced by WMnet

Stuff about Technology and School Networks

This site is not focussed on the network technology behind video conferencing as this is varies a great deal by specific implementation. However there are some key technical concepts that should be considered:

Bandwidth - How much traffic there is on the network
Firewalls - How the flow of data into the school from the outside is restricted
Proxy Servers - How the flow of data from the school network is managed
Switches and Hubs - The different components that make up the physical network in the school

A video conference is made possible by two computers being able to send data to each other. This data must travel across the network inside the school, across the wide area network or the Internet to the other participants in the conference, then back again.

Video and audio data is different from normal web browsing in that it is time-sensitive - that is the order that information arrives in, and the delay caused by the network has a big impact on the overall experience.

The challenge to the network manager is to make sure the network used is able to transmit the data as fast as possible and in the right order.

This sounds simple enough but other parts of the network might prevent this.

The amount of traffic on the network, compared to its size, can lead to congestion. If a network is congested then data is held in a queue or discarded - this can be especially damaging to video conferencing and leads to gaps or pauses in the transmission.

It may be possible to reserve parts of your network for different types of traffic so there is enought bandwidth set aside for all the applications.

The Diagram bellow illustrates how the flow of "traffic" along a network can be managed to give dedicated routes for different types of data.

Firewalls prevent unwanted communication from one network to another, however some are not able to properly allow video conferencing traffic through.

Proxy Servers increase perceived performance of the network by storing copies of content and then returning these copies rather than originals that might be far away on the network. Video conferencing, being real time, does not benefit from proxy servers, yet some school networks force all traffic through such a server. This might prevent video conferencing working at all, or simply reduce performance. It is preferable to ensure video conferencing traffic does not go through a standard proxy server.

Switches and hubs make up the core of any network, connecting the bits of wire that are stretched around a school. Hubs are much less efficient than switches, and should be avoided where possible. Modern switches tend to be able to support the performance requirements of video conferencing more than adequately.

For more information on these technical topics have a look at the Links page.