The bandwidth consumption of a virtual classroom room (VC) depends on the features used in the VC. Adobe Connect is very efficient with bandwidth consumption. It is used extensively by clients with tight bandwidth restrictions, such as DoD and far-flung remote rural offices, activities, etc. With that stated, while there are very efficient use-cases, there are also some more bandwidth intensive use cases. And some less efficient use-cases can be easily avoided without detracting from the training experience.

For example, sharing an uploaded slide deck from the Meeting is the most efficient while using the screen-sharing feature is less efficient. I am always chagrined when I join a Meeting wherein the Presenter is using screen-sharing to show a PowerPoint deck. By uploading it to the Adobe Connect Share pod and allowing the server to mete it out, bandwidth consumption is cut by nearly 80% and any latency from network distance or other variables is made less acute. Screen-sharing a PowerPoint deck is simply a bad practice and should be avoided even if there is bandwidth to spare as VC performance is always better with best practices.

One bandwidth sensitive practice often employed in a small Virtual class it is to have all students in a classroom running their webcams at once and actually looking the teacher in the eye and visa-versa. While Adobe Connect has no official limit to the number of webcams in a meeting, it is prudent, based on the real-estate in any Meeting pod along with other practical considerations such as how many can you see at once, to limit the number to to no more than 12-15.

Note: There is a filmstrip mode supported which allows this number to increase, but then it is not an all in the front row VC experience and instead is more like one-at-a-time in full view to many thumbnails. If that is acceptable, then the live video bandwidth usage diminishes considerably.

Let’s address the question of how would you predict the amount of bandwidth used in a VC when all students are up front and visible in Video pods by using an example of the 5 camera feeds into a recent team meeting I attended – a celebrity panel of Adobe Connect minds. See the bandwidth indicator on my client. My client camera pod is pushing 500 kbps up to the Meeting and it is pulling down 2 mbits from the server:

In this Meeting, integrated telephony was used so there is not need to calculate VoIP estimates, just video. The Meeting is set to use HD which is the highest quality setting in Adobe Connect and can be adjusted under the Meeting menu item int he VC:

Meeting>Preferences>Video

The math is very simple; there were five HD video feeds into the Video pod so upstream, we had have five feeds going to the server and downstream had 4 feeds to each participant (n-1). This is a total of 21 streams including both upward and downward video streams. In the case of the HD video quality, 500 kbps per user x 21 = 10500 kbps or 1.3MB just for the video and not including any other features employed such as anything displayed displayed in the Share Pod, etc.

See the following chart of downstream estimates per client to estimate the bandwidth usage in Adobe Connect by feature and develop your use case as appropriate:

Let’s consider a another quite different possible VC scenario: A large VC with 100 participants within which an uploaded PowerPoint deck will be shared. The Presenter/instructor will use a webcam to talk one-to-many using VoIP. Most participants will be using the HTML client although the Adobe Connect Meeting application is also an available client option.

• Upstream from the Meeting Presenter/Host will be the Camera running HD quality and a VoIP stream: 100kbps for VoIP plus 500kbps for the Webcam (rounded up) = 600
• Downstream from the server to the participants: The PPTX slides will be very economical with HTML5, 70 x 100=7000 kbps. The HD camera feed to each client will be more bandwidth intensive 50000 kbps or just over 6MB.
• Total bandwidth used by this Meeting at the firewall protecting the server will be just over 7MB. This can be lowered significantly by lowering the quality of the camera feed or by putting a picture of the speaker in the place of the Video Pod: 2MB.

Using the chart above it is easy to plan the bandwidth usage by an Adobe Connect server or cluster and it is also very nice to see just how economical many Adobe Connect use-cases can be with refection to bandwidth utilization.

For detailed Adobe Connect VC bandwidth test data manifested from Wireshark output,  see the following tech-note: http://blogs.adobe.com/connectsupport/adobe-connect-bandwidth-utilization/