How can I determine if my network infrastructure can support a video conferencing system? What video conferencing network requirements, if any, do I need to meet?
Video conferencing is one of the most demanding applications to run on an enterprise network. Video is a real-time service and uses UDP packets for delivering the video, audio and shared content portions of the call. Packet size is large and varies considerably. Packets must be delivered within a strict time window or they will be discarded. Packet loss due to bandwidth constraints or network problems can have significant impact on a video call.
These are the generally accepted guidelines for networks running video conferencing applications:
- Packet loss should be less than .1 % when averaging over a 5-minute period
- Jitter should be 30 ms or less
- One-way latency should be 150 ms or less
- Adequate bandwidth must be available to accommodate all of the video calls that will occur on a specific link during a given time period
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In order to achieve these performance figures, it is necessary to implement quality of service (QoS) on the network. The exception is if video is the only application on a standalone network. MPLS, private line or other technologies that provide guaranteed bandwidth and QoS support are appropriate for corporate-quality video conferencing. It is possible to run video over the Internet, but calls will be subject to periodic disturbances, which can be quite severe. This may be tolerable for a telecommuting worker who may be calling in to a department meeting, but it is generally not an acceptable standard for video calls between board-level executives.
Modern network equipment has QoS support built in and most business-grade carriers can provide QoS-ready connectivity. Implementing QoS requires designating video packets with Differentiated Services Code Point (DSCP) marks at a trust boundary, providing preferential treatment for those packets to avoid delays at congestion points or possible packet loss, and handing off the DSCP marks to the network service provide at the WAN edge. Good references for this process include "Configuration Guidelines for DiffServ Service Classes," or RFC 4594; and "End-to-End QoS Network Design: Quality of Service in LANs, WANs, and VPNs," by Tim Szigeti and Christina Hattingh.
There is a commonly held misconception that if a network will support VoIP, then it will also support video conferencing. Unfortunately, this is generally not the case. VoIP is much less impacted by other applications on the network than video, and special preparations must be made to make the network ready for video. This can be done by requesting a video network assessment from a video equipment manufacturer, reseller or service provider. Alternatively, this task can be assigned to the enterprise network team, although the network group will often be resource-limited and may lack experience in this specialized area.
Learn more about video conferencing network needs and requirements:
- What video conferencing means for the network
- Bandwidth requirements for video conferencing over WAN
- Managing video conferencing bandwidth demand
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