Interconnect a Wazo to a VoIP provider

When you want to send and receive calls to the global telephony network, one option is to subscribe to a VoIP provider. To receive calls, your Wazo needs to tell your provider that it is ready and to which IP the calls must be sent. To send calls, your Wazo needs to authenticate itself, so that the provider knows that your Wazo is authorized to send calls and whose account must be credited with the call fare.

The steps to configure the interconnections are:

• Establish the trunk between the two Wazo, that is the SIP connection between the two servers
• Configure outgoing calls on the server(s) used to emit calls
• Configure incoming calls on the server(s) used to receive calls

Establish the trunk

You need the following information from your provider:

• a username
• a password
• the name of the provider VoIP server
• a public phone number
• POST /trunks {"context": "ctx-<tenant slug>-incall-<UUID>"} (or another incoming call context)
• POST /endpoints/sip {"username": <username>, "secret": <password>, "type": "peer", "host": "voip.provider.example.com"}
• PUT /trunks/{trunk_id}/endpoints/sip/{sip_id}
• POST /registers/sip {"auth_username": <username>, "auth_password": <password>, "transport": "udp", "remote_host": "voip.provider.example.com"}
• PUT /trunks/{trunk_id}/registers/sip/{sip_id}

If your Wazo is behind a NAT device or a firewall, you should set the following:

• PUT /endpoints/sip {"options": [..., ["qualify", "yes"], ...]}

This option will make Asterisk send a signal to the VoIP provider server every 60 seconds (default settings), so that NATs and firewall know the connection is still alive. If you want to change the value of this cycle period, you have to select the appropriate value of the following parameter:

• PUT /endpoints/sip {"options": [..., ["qualifyfreq", <value>], ...]}

At that point, the Asterisk command sip show registry should print a line showing that you are registered, meaning your trunk is established.

Set the outgoing calls

The outgoing calls configuration will allow Wazo to know which extensions will be called through the trunk.

• POST /outcalls
• PUT /outcalls/{outcall_id}/trunks
• POST /extensions {"exten": "418.", "context": "ctx-<tenant slug>-outcall-<UUID>"}
• PUT /outcalls/{outcall_id}/extensions/{extension_id}

This will tell Wazo: if an internal user dials a number beginning with 418, then try to dial it on the trunk associated.

The most useful special characters to match extensions are:

• . (period): will match one or more characters
• X: will match only one character

You can find more details about pattern matching in Asterisk (hence in Wazo) on the Asterisk wiki.

Set the incoming calls

Now that we have calls going out, we need to route incoming calls.

To route an incoming call to the right destination in the right context, we will create an incoming call.

• POST /extensions {"exten": <public_phone_number>, "context": "ctx-<tenant slug>-incall-<UUID>"}
• POST /incalls {"destination": {"type": "user", "user_id": <the_front_desk_guy_id>}}
• PUT /incalls/{incall_id}/extensions/{extension_id}

This will tell Wazo: if you receive an incoming call to the public phone number in the context ctx-<tenant slug>-incall-<UUID>, then route it to the user the_front_desk_guy_id. The destination context will be found automatically, depending on the context of the line of the given user.