RTCIceCandidate: tcpType property

Baseline 2024
Newly available

Since May 2024, this feature works across the latest devices and browser versions. This feature might not work in older devices or browsers.

The RTCIceCandidate interface's read-only tcpType property is included on TCP candidates to provide additional details about the candidate type.

The tcpType field's value is set from the candidateInfo options object passed to the RTCIceCandidate() constructor. You can't specify the value of tcpType directly in the options object, but its value is automatically extracted from the object's candidate a-line, if it's formatted properly.

Value

If the protocol is "tcp", tcpType has one of the following values:

"active"

The transport will try to open an outbound connection but won't receive incoming connection requests.

"passive"

The transport will receive incoming connection requests but won't try to open an outbound connection.

"so"

The transport will try to open a connection simultaneously with its peer.

tcpType is null for UDP candidates.

Examples

In this example, the candidate's protocol and tcpType are used to adjust the user interface for simultaneous-open TCP candidates.

js
if (candidate.protocol === "tcp" && candidate.tcpType === "so") {
  adjustForSimultaneousOpen(candidate);
}

Specifications

Specification
WebRTC: Real-Time Communication in Browsers
# dom-rtcicecandidate-tcptype

Browser compatibility

See also