Integrate Twilio into BigBlueButton so that users can join a meeting with a dial-in number.
The built-in WebRTC-based audio in BigBlueButton is very high quality audio. Still, there may be cases where you want students to be able to dial into the conference bridge using a telephone number.
For example, some students might have poor connectivity and may face cracking or delayed audio during an online class. Or, some online classes are just lectures that students just need to listen to.
If you have been running BigBlueButton servers for a while, you might have received complains from your users about poor audio quality.
Well, integrating a phone number into your online classes is a great way to mitigate such audio issues.
We are going to get a phone number from Twilio and configure FreeSWITCH accordingly to receive incoming calls via session initiation protocol (SIP) fromTwilio.
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Login to your Twilio account and navigate to the Dashboard to Elastic SIP Trunking by clicking the dropdown menu in the left side. Click on Trunks to provision an Elastic SIP Trunk.
I am going to list-out key steps that you need to perform:
- Termination URL: Give a unique identifier (example - your project name) to identify your Termination SIP URI. You will use this URI to set-up FreesSWITCH later.
- Originating URI: Give the public IP of your BigBlueButton server in the following format: sip:BBB_PUBLIC_IP
- IP Access Control Lists: Go to Elastic SIP Trunking > Authentication > IP / CIDR Access Control Lists to add public IP your BigBlueButton server. You can add your public IP in the following format: BBB_PUBLIC_IP / 32
- Credential Lists: Add a creential. Enter a name and use your Twilio Username and Password.
That's all you would need to setup a phone number for your BigBlueButton classes. For additional information, check-out getting started guide on Elastic SIP Trunking.
I am assuming you have a standard BigBlueButton installation, where FreeSWITCH is running on the same machine as your BigBlueButton server.
Edit /opt/freeswitch/conf/sip_profiles/external.xml and change
<param name="ext-rtp-ip" value="$${local_ip_v4}"/>
<param name="ext-sip-ip" value="$${local_ip_v4}"/>To
<param name="ext-rtp-ip" value="$${external_rtp_ip}"/>
<param name="ext-sip-ip" value="$${external_sip_ip}"/>Edit /opt/freeswitch/conf/vars.xml, and change
<X-PRE-PROCESS cmd="set" data="external_rtp_ip=stun:stun.freeswitch.org"/>
<X-PRE-PROCESS cmd="set" data="external_sip_ip=stun:stun.freeswitch.org"/>To
<X-PRE-PROCESS cmd="set" data="external_rtp_ip=BBB_PUBLIC_IP"/>
<X-PRE-PROCESS cmd="set" data="external_sip_ip=BBB_PUBLIC_IP"/>I am assuming 5060 is the default SIP port. We need to open this port for UDP connections.
sudo ufw allow 5060/udpYou can verify external-sip-port in /opt/freeswitch/conf/vars.xml
In your Twilio account, check Networking Info section under Elastic SIP Trunking. You will find Twilio IP addresses that you should whitelist for post 5060/UDP. With these rules, you won’t get spammed by bots scanning for SIP endpoints and trying to connect.
cp sip_profile_twilio.xml /opt/freeswitch/conf/sip_profiles/external/twilio.xmlDownload the sample SIP profile, sip_profile_twilio.xml and make the following changes:
- Set gateway name to the Termination URL that you created above while setting up Twilio Elastic SIP Trunk. The gateway name would have the following format: my-project-name.pstn.twilio.com.
- Set proxy the same as the gateway name.
- Set username and password the same as your Twilio username and password. Check Credential Lists
After making above changes, copy SIP profile to /opt/freeswitch/conf/sip_profiles/external/
cp dialplan_twilio.xml /opt/freeswitch/conf/dialplan/public/twilio.xmlTo route the incoming call from Twilio to the correct BigBlueButton audio conference, you need to create a dialplan which, for FreeSWITCH, is a set of instructions that it runs when receiving an incoming call.
When a user calls the phone number, the dialplan will prompt the user to enter a five digit number associated with the conference.
Value of field destination_number is customized for Twilio so that it will accept
- the dial-in number format startig with either + or 00
- single digit nnumber between 1 and 9 for USA number. This can be changed to [1-9]{2} for France (33) or India (91)
- 10 digit number between 0 and 9 for USA number. This can be changed to [0-9]{x}, where x = number of remaining digits in the dial number
Change ownership of this file to freeswitch:daemon
chown freeswitch:daemon /opt/freeswitch/conf/dialplan/public/twilio.xmland then restart FreeSWITCH:
sudo systemctl restart freeswitchTry calling the phone number. It should connect to FreeSWITCH and you should hear a voice prompting you to enter the five digit PIN number for the conference. Please note, that dialin will currently only work if at least one web participant has joined with their microphone.
To always show users the phone number along with the 5-digit PIN number within BigBlueButton, edit /usr/share/bbb-web/WEB-INF/classes/bigbluebutton.properties and change 613-555-1234 to the phone number provided by Twilio
defaultDialAccessNumber=613-555-1234and change defaultWelcomeMessageFooter to
defaultWelcomeMessageFooter=<br><br>To join this meeting by phone, dial:<br> %%DIALNUM%%<br>Then enter %%CONFNUM%% as the conference PIN number.Save bigbluebutton.properties and restart BigBlueButton again.
Each user that joins a session will see a message in the chat similar to.
To join this meeting by phone, dial:
613-555-1234
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