{{APIRef("WebRTC")}}{{draft}}
The RTCConfiguration
dictionary is used to provide configuration options for an {{domxref("RTCPeerConnection")}}. It may be passed into the constructor when instantiating a connection, or used with the {{domxref("RTCPeerConnection.getConfiguration()")}} and {{domxref("RTCPeerConnection.setConfiguration()")}} methods, which allow inspecting and changing the configuration while a connection is established.
The options include ICE server and transport settings and identity information.
Properties
bundlePolicy
{{optional_inline}}- Specifies how to handle negotiation of candidates when the remote peer is not compatible with the SDP BUNDLE standard. This must be one of the values from the enum
RTCBundlePolicy
. If this value isn't included in the dictionary,"balanced"
is assumed. certificates
{{optional_inline}}- An {{jsxref("Array")}} of objects of type {{domxref("RTCCertificate")}} which are used by the connection for authentication. If this property isn't specified, a set of certificates is generated automatically for each {{domxref("RTCPeerConnection")}} instance. Although only one certificate is used by a given connection, providing certificates for multiple algorithms may improve the odds of successfully connecting in some circumstances. See {{anch("Using certificates")}} below for additional information.
This configuration option cannot be changed after it is first specified; once the certificates have been set, this property is ignored in future calls to {{domxref("RTCPeerConnection.setConfiguration()")}}.
iceCandidatePoolSize
{{optional_inline}}- An unsigned 16-bit integer value which specifies the size of the prefetched ICE candidate pool. The default value is 0 (meaning no candidate prefetching will occur). You may find in some cases that connections can be established more quickly by allowing the ICE agent to start fetching ICE candidates before you start trying to connect, so that they're already available for inspection when {{domxref("RTCPeerConnection.setLocalDescription()")}} is called.
Changing the size of the ICE candidate pool may trigger the beginning of ICE gathering.
iceServers
{{optional_inline}}- An array of {{domxref("RTCIceServer")}} objects, each describing one server which may be used by the ICE agent; these are typically STUN and/or TURN servers. If this isn't specified, the ICE agent may choose to use its own ICE servers; otherwise, the connection attempt will be made with no STUN or TURN server available, which limits the connection to local peers.
iceTransportPolicy
{{optional_inline}}- The current ICE transport policy; this must be one of the values from the
RTCIceTransportPolicy
enum. If this isn't specified,"all"
is assumed. peerIdentity
{{optional_inline}}- A {{domxref("DOMString")}} which specifies the target peer identity for the {{domxref("RTCPeerConnection")}}. If this value is set (it defaults to
null
), theRTCPeerConnection
will not connect to a remote peer unless it can successfully authenticate with the given name. rtcpMuxPolicy
{{optional_inline}}- The RTCP mux policy to use when gathering ICE candidates, in order to support non-multiplexed RTCP. The value must be one of those from the
RTCRtcpMuxPolicy
enum. The default is"require"
.
Constants
{{page("/en-US/docs/Web/API/RTCPeerConnection", "RTCBundlePolicy enum", 0, 1)}}
{{page("/en-US/docs/Web/API/RTCPeerConnection", "RTCIceTransportPolicy enum", 0, 1)}}
{{page("/en-US/docs/Web/API/RTCPeerConnection", "RTCRtcpMuxPolicy enum", 0, 1)}}
Using certificates
When you wish to provide your own certificates for use by an {{domxref("RTCPeerConnection")}} instead of having the RTCPeerConnection
generate them automatically, you do so through calls to {{domxref("RTCPeerConnection.generateCertificate()")}}.
This attribute supports providing multiple certificates because even though a given DTLS connection uses only one certificate, providing multiple certificates allows support for multiple encryption algorithms. The implementation of RTCPeerConnection
will choose which certificate to use based on the algorithms it and the remote peer support, as determined during DTLS handshake.
If you don't provide certificates, new ones are generated automatically. One obvious benefit to providing your own is identity key continuity—if you use the same certificate for subsequent calls, the remote peer can tell you're the same caller. This also avoids the cost of generating new keys.
<<<link to added info on identity>>>
Example
The configuration below establishes two ICE servers. The first one, stun:stun.services.mozilla.com
, requires authentication, so the username and password are provided. The second server has two URLs: stun:stun.example.com
and stun:stun-1.example.com
.
var configuration = { iceServers: [{ urls: "stun:stun.services.mozilla.com", username: "[email protected]", credential: "webrtcdemo" }, { urls: ["stun:stun.example.com", "stun:stun-1.example.com"] }] }; var pc = new RTCPeerConnection(configuration);