Most companies today are maximizing their travel budgets and communication requirements by making smart use of video conferencing as an alternative to face-to-face meetings. With this decision to implement enterprise-grade video conferencing comes the requirement for reliable and cost-effective bandwidth solutions.
Video conferencing can take advantage of the existing public telephone network, a private IP network, or the Internet. The target bandwidth for interactive video communications is in the range of 300K to 400K bit/sec per stream. This includes audio and video as well as control signaling.
The H.323 protocol does not require that two or more terminals in a session send the same data rate as they receive. A low-power endpoint might only be able to encode at a rate of 100,000 bps, but because decoding requires less processor usage, it could decode a 300,000 bps video stream.
However, in video conferencing, the bandwidth is assumed to be symmetrical. In full-duplex networks such as ISDN, Ethernet, ATM, and time-division multiplexed networks, capacity is expressed as bandwidth in one direction, even though the same bandwidth is available to traffic in the opposite direction.
You need to estimate the number of concurrent sessions your network needs to support and find out if your network has end-to-end bandwidth.
A T-1 bandwidth circuit offers 1.5 Mbit/sec in each direction and would be ample bandwidth for two 512K bit/sec or three 384K bit/sec video conferences, depending on the amount of concurrent traffic on the circuit. network. Also, make sure you have 10/100 switched Ethernet on all LAN segments where video conferencing traffic is expected.
Multipoint conference bandwidth (with which three or more parties can see and hear each other) is calculated separately from point-to-point sessions. Multipoint can be done in IP or ISDN environments, and some conference units support both network types.
Multipoint conferencing products can be software-based or accelerated with special hardware, and their configuration can lead to different bandwidth consumption patterns as well as different user experiences. For example, when an endpoint is used to host a multipoint conference, the maximum bandwidth for any individual participant is the bandwidth allocated to that host divided by the number of participating locations. When you need to have more than four locations on a call at the same time, network-based products are recommended.
If you decide that your IP network cannot handle the additional traffic associated with live video sessions in a merged or converged network deployment, your options are to rely on circuit-switched networks or deploy additional IP bandwidth capacity. To help determine and purchase the exact bandwidth to meet your requirements… using a free technical consultation service, such as through DS3-Bandwidth.com, is highly recommended. Additionally, an excellent resource for guidance on setting up and managing video conferencing is available at “Video Conferencing Solutions.”
