This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

The read-only property RTCPeerConnection.iceConnectionState returns an enum of type RTCIceConnectionState which state of the ICE agent associated with the RTCPeerConnection.

You can detect when this value has changed by watching for the iceconnectionstatechange event.


var state = peerConnection.iceConnectionState;


The current state of the ICE agent and its connection. The value is one of the strings in the RTCIceConnectionState enum.

RTCIceConnectionState enum

The RTCIceConnectionState enum defines the string constants used to describe the current state of the ICE agent and its connection to the ICE server (that is, the STUN or TURN server).

Constant Description
"new" The ICE agent is gathering addresses or is waiting to be given remote candidates through calls to RTCPeerConnection.addIceCandidate() (or both).
"checking" The ICE agent has been given one or more remote candidates and is checking pairs of local and remote candidates against one another to try to find a compatible match, but has not yet found a pair which will allow the peer connection to be made. It's possible that gathering of candidates is also still underway.
"connected" A usable pairing of local and remote candidates has been found for all components of the connection, and the connection has been established. It's possible that gathering is still underway, and it's also possible that the ICE agent is still checking candidates against one another looking for a better connection to use.
"completed" The ICE agent has finished gathering candidates, has checked all pairs against one another, and has found a connection for all components.
"failed" The ICE candidate has checked all candidates pairs against one another and has failed to find compatible matches for all components of the connection. It is, however, possible that the ICE agent did find compatible connections for some components.
"disconnected" Checks to ensure that components are still connected failed for at least one component of the RTCPeerConnection. This is a less stringent test than "failed" and may trigger intermittently and resolve just as spontaneously on less reliable networks.
"closed" The ICE agent for this RTCPeerConnection has shut down and is no longer handling requests.


var pc = new RTCPeerConnection();
var state = pc.iceConnectionState;


Specification Status Comment
WebRTC 1.0: Real-time Communication Between Browser
The definition of 'RTCPeerConnection.iceConnectionState' in that specification.
Working Draft Initial specification.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) 22 (22) [1] No support (Yes) ?
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support ? ? 22 (22) [1] No support ? ?

[1] Though this property is not prefixed, the RTCPeerConnection it belongs to is, until Firefox 44.

See also


© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.

Experimental Expérimental Property Read-only Reference Référence RTCPeerConnection WebRTC