Twilio’s Network Traversal Service is a globally distributed STUN/TURN service that helps you deploy more reliable peer-to-peer communications applications. You can use this service in your WebRTC and VoIP applications for traversal and relay around NAT/firewalls, so that your users make a successful connection every time.
If you're new to STUN/TURN and ICE, check out the Frequently Asked Questions. If you want to start using Twilio's Network Traversal Service immediately, here's what you need to do.
Using Network Traversal Service in a WebRTC application is as easy as requesting a token and passing it to your RTCPeerConnection constructor.
First, make a request from your web server to retrieve a Network Traversal Service Token and pass it to your WebRTC application.
Important: You'll need to use your Twilio AccountSid and AuthToken to get a Network Traversal Service Token. You should only make this request from your server and not the client browser to keep your Twilio account credentials safe.
Next, include the "ice_servers" property in the RTCConfiguration object you pass to the RTCPeerConnection constructor when setting up a call, as shown below (where ICE_SERVERS is the contents of the "ice_servers" property returned in the response above):
From this point forward, exchange SDP offer/answers as you normally would. Congrats, you've now used Network Traversal Service to setup a connection!
If the browser you're using supports Trickle ICE, you'll also want to handle the RTCPeerConnection's onIceCandidate event to pass any new ICE candidates to the connected peer:
That's all there is to it! If you need more help, check out the Frequently Asked Questions, or contact Twilio support at firstname.lastname@example.org.
In order to use Network Traversal Service in a VoIP client, you'll need to be able to make an HTTP request from your VoIP client or another application at least once every 24 hours to retrieve a new ephemeral token.
To use Network Traversal Service with a VoIP Client you'll do the following:
- Retrieve a Network Traversal Service Token.
- Retrieve the STUN and TURN URLs from the returned data, along with the username and credential values.
- Configure your VoIP client with these values.
Network Traversal Service Tokens are good for a maximum and default value
of one day. You can reduce the token expiration time by using the
parameter when you request the token. Find out more in the
Network Traversal Service Token documentation here.