Bandwidth Management for Enterprise Video Conferencing

There is never enough internet bandwidth. With the value of teleconferencing and telepresence firmly established, the demands placed upon an organization’s network have risen significantly. Dr. Chris Lauwers, CTO at Avistar, laid out the problem and offered a solution in his presentation ‘Bandwidth Management: Critical Factor for Enterprise Videoconferencing’ at the 2011 National Association of Broadcaster’s convention in Las Vegas this week (April 11th – 14th).

While personal video and even HD video rooms can get by with less than 2 gb/s, telepresence consumes 4 -12 gb/s per call. Such demands could impact mission-critical applications, an unacceptable situation. A massive (and expensive) upgrade of the organization’s network would resolve the issue, but the cost and the inevitable growth of network traffic suggests a better solution would be wisely managing the present network.

A reliable enterprise video deployment must guarantee the necessary bandwidth is available for the duration of the call and assure video calls don’t try to consume more bandwidth than is available. Some people might ask “Isn’t this an issue Quality of Service tools can handle?” Dr. Lauwer pointed out QoS sets priorities for traffic, it does not reserve capacity for any application. At rush hour, even priority traffic suffers from congestion. QoS works with bandwidth management to make sure the voice and video traffic permitted on the net get the real-time treatment they need.

Dr. Lauwer described bandwidth management as “a collection of integrated and dynamic mechanisms and policies that control and manage bandwidth used by Unified Communications”. It should be integrated at the application level rather than the network level for ease of management and optimal user experience. Making applications “network aware” allows the applications to handle policy while the network deals with the mechanism. Effective operation of application-level bandwidth management requires integration with the network layer.

The benefits of this approach include scaled deployment on existing networks rather than adding special-purpose networks, protection of mission-critical applications from negative impact, and delivery of the best end-user experience within the constraints of the present network.

Centralized Call Rate provisioning, based upon “Classes of Users” and their locations allows the network administrator to selectively limit bandwidth utilization to accommodate important traffic without unnecessarily compromising audio-video quality. Call rate provisioning can be adjusted as traffic changes, thereby avoiding bandwidth reallocation in the middle of a call.

Call Admission Control checks the route for a given call, assuring adequate bandwidth is available, before the call is established. If there is not enough bandwidth at any point in the route, the call fails. A user can try later or might be advised to consider an alternative “communication modality”.

Dr. Lauwer concluded by offering a vision of the future where a single, integrated, bandwidth management system, able to deal with security and audits, proxies, performance, topology, policies, permissions and pools of bandwidth, will manage global networks.