Technical requirements for the use of BigBlueButton (BBB)

To use BigBlueButton, a fast and stable internet connection, preferably wired (LAN), is required. In case only WiFi is available, please use the 5Ghz network and remain in close proximity to the access point (DSL router). A stable mobile connection is only possible when using 4G / LTE – always make sure you have good reception. Please prevent or abort any other processes such as updating, downloading, file sharing or streaming you or someone else in the same network is running simultaneously.

Please also read: Technical requirements for the proper use of the Virtual Venue

Since data transfer for video conferences and webinars has to be lossless and must take place within a short time span, there are special requirements and various factors that need to be considered.

Video transmission:

With the camera turned on and a 320 x 240 pixels (default) resolution, a video data stream of ca. 250 kbps can be expected. Higher quality videos required 400 kbps – 600 kbps. The data streams for individual active webcams will not be merged and will therefore be added on the server. If your own camera is active, you will need at least 250 kbps upload rate for your camera plus 'n' multiplied by 250 kbps download rate for every other active camera that belongs to the other attendees.

Audio transmission:

For the audio data stream, attendees can calculate with an upload (in case the own microphone is activated) and download rate of ca. 40 kbps. It doesn’t matter how many attendees are using their microphones as the audio data will be merged on the server and a person will only receive one data stream.

Screen sharing:

A shared screen will be transmitted as video and, due to common display resolutions, in Full HD. Sharing requires a high data rate which usually means 1000 kbps or more. If you are sharing your screen’s content, an upload data rate of 1000 kbps is required. You will need the same data rate for downloading when someone else shares their screen with you.

Example 1

A typical classroom situation with 1 speaker (webcam and microphone active, screen sharing) and 30 participants (inactive webcam and microphone).

For the speaker: 1000 kbps (screen sharing) + 250 kbps (webcam) + 40 kbps (audio) = 1290 kbps upload and 40 kbps download. For all other participants: 250 kbps (webcam) + 40 kbps (audio) = 290 kbps upload and 1290 kbps download.

This example illustrates that even in this relatively simple situation, you need to consider large amounts of upload data for the speakers. A 1000 kbps upload bandwidth which is usually associated with DSL 16000 connections would no longer be sufficient to ensure a stable presentation. Keep this in mind when planning your presentation. Participants should be able to use their bandwidth without any difficulties.

Example 2

A breakout room where a group of 5 participants (5 webcams and microphones active, no screen sharing) gather for a discussion:

All persons in the room are equal and need 250 kbps (webcam) + 40 kbps (audio) = 290 kbps upload rate and 4 * 250 kbps + 40 kbps = 1040 kbps download rate

Even if this situation will be unlikely to cause any problems for participants and their available bandwidth, it also shows that a considerable amount of data is transferred for a relatively small number of participants.

NOTE: We have integrated a TURN server in the BBB cluster, which should ensure access through firewalls with port blocking. This TURN server tunnels the BBB requests (UDP) over HTTPS port 443 and should work in most cases even with restrictive firewalls. It would be best to test this in a BBB meeting in advance. For more information, see the following article: Firewall Configuration for BigBlueButton When Connecting to Corporate Networks and VPNs