RTCOfferOptions.iceRestart

The iceRestart property of the RTCOfferOptions dictionary is a Boolean value which, when true, tells the RTCPeerConnection to start ICE renegotiation.

A Boolean value indicating whether or not the RTCPeerConnection should generate new values for the connection's ice-ufrag and ice-pwd values, which will trigger ICE renegotiation on the next message sent to the remote peer.

When the RTCPeerConnection object's ICE connection state changes to failed, you should try to trigger an ICE restart. You should ideally do this by calling the RTCPeerConnection's restartIce() method, if it's available.

Fundamentally, this renegotiation is triggered by generating and using new values for the ICE username fragment ("ufrag")}}

This example shows a handler for the iceconnectionstatechange event. It watches for the ICE connection state to transition to "failed", which indicates that an ICE restart should be tried in order to attempt to bring the connection back up.

pc.oniceconnectionstatechange = function(evt) {
  if (pc.iceConnectionState === "failed") {
    if (pc.restartIce) {
      pc.restartIce();
    } else {
      pc.createOffer({ iceRestart: true })
      .then(pc.setLocalDescription)
      .then(sendOfferToServer);
    }
  }
}

If the state changes to failed, this handler starts by looking to see if the RTCPeerConnection includes the restartIce() method; if it does, we call that to request an ICE restart. Otherwise, we call back to the older technique: we manually create a new offer with iceRestart set to true, then that offer is set as the new local description for the connection. After that, the offer is sent to the server by calling a custom function sendOfferToServer().