How to determine if TURN is used in a test?

You may want to know in a test result if the media was sent directly or relayed via a TURN server. And if it went through a TURN server, you’d like to know if that was done over UDP, TCP, or TLS.

For that, if you run tests or monitors in testRTC, or if you’re just uploading a webrtc-internals dump file to analyzeRTC directly, you can follow these instructions to find out (video below):

Probe level graphs have an Internals button that enables you to access the testRTC Internals information. You can find this button top right of the screen. This will get you to the advanced analysis section which shows a lot more data for debugging purposes.
Look at the ICE Candidate pairs table. Scroll down the page until you pass the state machine diagrams. That’s where the ICE Candidate pairs table appear. In that table, look at the green candidate pairs – these are the active ones. Usually, you’ll have just one of these. Locate in the active candidate pair the type of connection – there’s one for the local candidate and one for the remote candidate. If one of these is marked as relay, then the session was connected over a TURN relay. You will see the type (udp, tcp or tls) next to the word relay.
Here’s a short video to show you how to do it.