The RTCIceTransport method getSelectedCandidatePair() returns an RTCIceCandidatePair object containing the current best-choice pair of ICE candidates describing the configuration of the endpoints of the transport.


candidatePair = RTCIceTransport.getSelectedCandidatePair();



Return value

A RTCIceCandidatePair object describing the configurations of the currently-selected candidate pair's two endpoints. local describes the configuration of the local end of the connection, while remote describes the remote peer's configuration.

The return value is null if no pair of candidates has been selected yet.

Usage notes

As the ICE agent performs negotiation of a RTCPeerConnection, it gathers and analyzes candidate configurations from each the two peers. As soon as it finds an acceptable matching pair of candidates, meeting the requirements for the connection, a selectedcandidatepairchange event is fired at the RTCIceTransport. From that time forward, the best matching pair of candidates will always be available by calling getSelectedCandidatePair().

As ICE negotiation continues, any time a pair of candidates is discovered that is better than the currently-selected pair, the new pair is selected, replacing the previous pairing, and the selectedcandidatepairchange event is fired again.

Note: It's possible for one of the configurations in the selected candidate pair to remain unchanged when a new pairing is chosen.


In this example, an event handler for selectedcandidatepairchange is set up to update an on-screen display showing the protocol used by the currently selected candidate pair.

var iceTransport = pc.getSenders()[0].transport.transport;
var localProto = document.getElementById("local-protocol");
var remoteProto = document.getElementById("remote-protocol");

iceTransport.onselectedcandidatepairchange = function(event) {
  var pair = iceTransport.getSelectedCandidatePair();
  localProtocol.innerText = pair.local.protocol.toUpperCase();
  remoteProtocol.innerText = pair.remote.protocol.toUpperCase();



Specification Status Comment
WebRTC 1.0: Real-time Communication Between Browsers
The definition of 'RTCIceTransport.getSelectedCandidatePair()' in that specification.
Candidate Recommendation Initial specification.

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support ? ? ? ? ? ?
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support ? ? ? ? ? ? ?


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Contributors to this page: Sheppy
Last updated by: Sheppy,