There are a number of areas to check, and it may be a combination of
problems that are causing the poor audio performance. The list below is
not exhaustive, but will give us some ideas of where to check further.
1. Bandwidth available to your hosted zone server. We recommend, at a
minimum, to have 100 Mbits/sec symmetrical bandwidth (both download and
upload speeds are, at least, 100 Mbits/sec). You want to validate what the
actual bandwidth to/from your hosted zone server is.
To test: do you have access to a second, external server with good
bandwidth? If so, can you try transferring a large file to/from your
hosted zone server to the second external server using scp to get a rough
idea what the maximum transfer rate is.
2. CPU available on your hosted zone server. In general, we recommend
running BigBlueButton on a dedicated (non-virtual) server. See
To test: try logging into the hosted zone server and watching the CPU using
top. Login with one, two, three, four, five, etc. external clients
(external to your corporate network). Does the CPU go above 70%? In our
experience, when the CPU consistently stays above 70%, you'll likely get
This test may not reveal that your hosted zone VM is on a host server that
is in heavy use by other virtual machines. In a virtualized environment,
there is no guarantee on how much CPU time your server will get. If it
can't keep up with incoming packets, audio will suffer.
Can your ISP provide you a dedicated server for testing BigBlueButton? If
so, that would help rule out running in a VM that is getting little CPU
3. Network connection to/from the hosted server from external clients is
To test: From the external clients (again external to your network), login
to BigBlueButton on your DMZ server behind your firewall and test that the
audio is good (this will calibrate that your external users
have sufficient and stable network to your server).
Then login to the hosted server and test the audio again. Is there a
difference? If the same clients are hearing a poorer experience on the
hosted zone VM, then the problem may not be the CPU of each server; rather,
it's the network connection to each server.
4. Clients network connection is poor.
To test: Have the clients use http://speedtest.net/. They may say their
ISP provides them a good connection, but http://speedtest.net/ will test
their upstream/downstream bandwidth and give you a reading on their actual
We recommend clients have 0.5 Mbits/second upload speed and 1.0
Mbits/second download speed. Of course, these are not hard numbers, and
BigBlueButton will certainly work with less bandwidth, but if your clients
have bandwidth in this range, they should experience good audio (assuming
that the problem is not 1, 2, or 3).
If you can, try some of the above tests and let us know the results.
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