SIP trunks: connect your own carrier to Bolna

A SIP trunk connects the carrier you already use to Bolna. Your numbers stay with your carrier, your carrier bills you for the minutes, and Bolna’s agents answer the calls that arrive on those numbers and place calls from them. You configure each direction once:

• Inbound. Your carrier sends calls for your numbers to Bolna’s SIP edge. Bolna accepts a call only from the carrier IP addresses you list on the trunk, then hands it to the agent assigned to the number that was called.
• Outbound. Bolna sends calls to your carrier’s gateway, presenting one of your trunk numbers as the caller ID. Your carrier authenticates Bolna by its IP address, by a username and password it issued to you, or both.

​

How a call flows

Signalling and audio both pass through Bolna’s edge. Your carrier never needs to reach Bolna’s internal media servers, so the addresses below are the only ones to configure.

​

Supported carriers

Any carrier that speaks standard SIP over UDP or TCP works. The dashboard has presets for Plivo, Telnyx, Twilio, Exotel, Vobiz and Vonage, plus Custom for any other carrier. A preset fills in the carrier’s gateway, port and transport where they are the same for every account, and shows a short checklist of what to set in that carrier’s console. The Plivo and Exotel presets also prefill the signalling IPs those carriers publish.

​

Limits

When every channel is in use, a new inbound call is refused with a 486 response, and a new outbound call waits in the queue until a channel frees up. See Troubleshooting for every SIP response Bolna can send. A trunk belongs to your account, which is your organization if you are in one, or to a sub-account when you create it with that sub-account’s API key. Its numbers can only be assigned to agents in the same scope. Organization members can view trunks; owners and admins can change them.

​

Get started