Documentation on video- or audo-conferencing software like Mumble, Jitsi, or Big Blue Button.

con·fer·ence | \ ˈkän-f(ə-)rən(t)s1a : a meeting ("an act or process of coming together") of two or more persons for discussing matters of common concern. Merriam-Webster

While irc can also be used to hold a meeting or conference, it's considered out of scope here.



With the rise of the SARS-COV-2 pandemic, even Tor, which generally works remotely, is affected because we were still having physical meetings from time to time, and we'll have to find other ways to deal with this. At the start of the COVID-19 pandemic -- or, more precisely, when isolation measures became so severe that normal in-person meetings became impossible -- Tor started looking into deploying some sort of interactive, real-time, voice and ideally video conferencing platform.

This was originally discussed in the context of internal team operations, but actually became a requirement for a 3-year project in Africa and Latin America. It's part of the 4th phase, to support for partners online. Tor has been doing training in about 11 countries, but has been trying to transition into partners on the ground, for them to do the training. Then the pandemic started and orgs are moving online for training. We reached out to partners to see how they're doing it. Physical meetings are not going to happen. We have a year to figure out what to do with the funder and partners. Two weeks ago gus talked with trainers in brazil, tried jitsi which works well but facing problems for trainings (cannot mute people, cannot share presentations). They tried BBB and it's definitely better than Jitsi for training as it's more like an online classroom.

Discussions surrounding this project started in ticket 33700 and should continue there, with decisions and facts gathered in this wiki page.


Must have

  • video/audio communication for a group of people of approx 2-10 people
  • specifically, work session for teams internal to TPI
  • also, training sessions for people outside of TPI
  • host partner organizations in a private area in our infrastructure
  • number of participants: 14 organisations with one training per month, max 4 per month, about 14-15 people per session, less than 20
  • chat fallback
  • have a mobile app
  • allow people to call in by regular phone
  • a way for one person to mute themselves
  • long term maintenance costs covered

Nice to have

  • Reliable video support. Video chat is nice, but most video chat systems usually require all participants to have video off otherwise the communication is sensibly lagged.
  • usable to host a Tor meeting, which means more load (because possibly > 20 people) and more tools (like slide sharing or whiteboarding)
  • respecting our privacy, peer to peer encryption or at least encrypted with keys we control
  • free and open source software
  • tor support


  • land a man on the moon

Approvals required

  • grant approvers
  • TPI (vegas?)

The budget will be submitted for a grant proposal, which will be approved by donors. But considering that it's unlikely such a platform would stay unused within the team, the chosen tool should also be approved by the TPI team as well. In fact, it would seem unreasonable to deploy such a tool for external users without first testing it ourselves.


  • april 2020: budget
  • early may 2020: proposal to funders
  • june 2020 - june 2021: fourth phase of the training project

Proposed Solution


Pessimistic estimates for the various platforms.

Each solution assumes it requires a dedicated server or virtual server to be setup, included in the "initial setup". Virtual servers require less work than physical servers to setup.

The actualy prices quoted from Hetzner but virtual servers would probably be hosted in our infrastructure which might or might not incur additional costs.


Platform One time Monthly Other
Mumble 20 hours €13 2h/person + 100$/person for headset
Jitsi 74 hours €54 + 10 hours
Big Blue Button 156 hours €54 + 8 hours


  1. Mumble is harder to use and has proven to absolutely require a headset to function reliably
  2. it is assumed that Jitsi and BBB will have similar hardware requirements. this is based on the experience that BBB seems to scale better than Jitsi but since it has more features might require comparatively more resources
  3. BBB is marked as having a lesser monthly cost because their development cycle seems slower than Jitsi. that might be too optimistic: we do not actually know how reliable BBB will be in production. preliminary reports of BBB admins seem to say it's fairly stable and doesn't require much work after the complex install procedure
  4. BBB will take much more time to setup. it's more complex than Jitsi, but it also requires an Ubuntu, which we do not currently support in our infrastructure (and an old version too, so upgrade costs were counted in the setup)
  5. current TPA situation is that we will be understaffed by 50% starting on May 1st 2020, and by 75% for two months during the summary. this project is impossible to realize if that situation is not fixed, and would still be difficult to complete with the previous staff availability.

A safe way to ensure funding for this project without threatening the sability of the team would be to hire at least part time worker especially for the project, which is 20 hours a month, indefinitely.


Assumed configuration

  • minimal Mumble server
  • no VoIP
  • no web configuration

One time costs:

  • initial setup: 4 hours
  • puppet programming: 6 hours
  • maintenance costs: near zero
  • Total: 10 hours doubled to 20 hours for safety

Recurring costs:

  • onboarding training: 2 hours per person
  • mandatory headset: 100$USD per person
  • CPX31 virtual server: €13 per month


Assumed configuration:

  • single server install on Debian
  • max 14 simultaneous users
  • dial-in capability

One time:

  • initial setup: 8 hours
  • Puppet one-time programming: 6 hours
  • Puppet Jigasi/VoIP integration: 6 hours
  • VoIP provider integration: 16 hours
  • Total: 36 hours, doubled to 72 hours for safety

Running costs:

  • Puppet maintenance: 1 hour per month
  • Jitsi maintenance: 4 hours per month
  • AX51-NVMe physical server: €54 per month
  • Total: 5 hours per month, doubled to 10 hours for safety, +€54 per month

Big Blue Button

Assumed configuration:

  • single server install on Ubuntu
  • max 30 simultaneous users
  • VoIP integration

One time fee:

  • initial setup: 30 hours
  • Ubuntu installer and auto-upgrade configuration: 8 hours
  • Puppet manifests Ubuntu port: 8 hours
  • VoIP provider integration: 8 hours
  • One month psychotherapy session for two sysadmins: 8 hours
  • Ubuntu 16 to 18 upgrade: 16 hours
  • Total: 78 hours, doubled to 156 hours for safety

Running costs:

  • BBB maintenance: 4 hours per month
  • AX51-NVMe physical server: €54 per month
  • Total: 4 hours per month, doubled to 8 hours for safety, +€54 per month

Alternatives considered



  • audio-only
  • moderation
  • multiple rooms
  • native client for Linux, Windows, Mac, iOS, Android
  • web interface (usable only for "listening")
  • chat
  • dial-in, unmaintained, unstable

Lacks video. Possible alternatives:



there are two different puppet modules to setup mumble:


still need to be evaluated, but i'd be tempted to use the voxpupuli module because they tend to be better tested and it's more recent



ansible roles:

puppet module:

there's also a docker container and (messy) debian packages

prometheus exporter:

Nextcloud Talk

systemli is using this ansible role to install coturn:



  • audio, video conferencing support
  • accesssible with live closed captionning and support for screen readers
  • whiteboarding and "slideshow" mode (to show PDF presentations)
  • moderation tools
  • chat box
  • embedded etherpad
  • dial-in support with Freeswitch
  • should scale better than jitsi and NC, at least according to their FAQ: "As a rule of thumb, if your BigBlueButton server meets the minimum requirements, the server should be able to support 150 simultaneous users, such as 3 simultaneous sessions of 50 users, 6 x 25, etc. We recommend no single sessions exceed one hundred (100) users."

i tested an instance setup by a fellow sysadmin and we had trouble after a while, even with two people, doing a screenshare. it's unclear what the cause of the problem was: maybe the server was overloaded. more testing required.


based on unofficial Debian packages, requires Freeswitch for dialin, which doesn't behave well under virtualization (so would need a bare metal server). Requires Ubuntu 16.04, packages are closed source (!), doesn't support Debian or other distros

anadahz setup BBB using a ansible role to install BBB.

Rejected alternatives

This list of alternatives come from the excellent First Look Media procedure:

  • Apple Facetime - requires Apple products, limited to 32 people and multiple parties only works with the very latest hardware, but E2EE
  • Cisco Webex - non-opensource, paid, cannot be self-hosted, but E2EE
  • Google Duo - requires iOS, Android, or web client, non-free, limited to 12 participants, but E2EE
  • Google Hangouts, only 10 people, Google Meet supports 250 people with a paid subscription, both proprietary
  • Jami - unstable but free software and E2EE
  • Keybase - chat only
  • Signal - chat only
  • Vidyo - paid service
  • Zoom - paid service, serious server and client-side security issues, not E2EE, but very popular and fairly reliable

Conference-hosting and larger-scale e-learning software:

  • bbb-scale - scale Big Blue Button to thousands of users
  • OpenCast - for hosting classes, editing, less interactive
  • Venueless - BSL, specialized in hosting conferences