RTCPeerConnections generate and parse SDP according to the standardized format. Exchanging SDP is needed to set up calls in WebRTC. Following the standard is important for cross-browser interoperability. Unified Plan also enables the RTCRtpTransceiver APIs. Changing from the old ("Plan B") to the new format can cause backwards-compatibility issues or break applications, see the Transition Guide: https://docs.google.com/document/d/1-ZfikoUtoJa9k-GZG1daN0BU3IjIanQ_JSscHxQesvU/edit?usp=sharing



Specification link

Specification currently under development in a Working Group

Status in Chromium


Enabled by default (tracking bug)

Consensus & Standardization

After a feature ships in Chrome, the values listed here are not guaranteed to be up to date.

  • Shipped/Shipping
  • In development
  • Positive



Since Chrome 65, this has been an experimental feature that you can opt-in to by passing sdpSemantics:'unified-plan' to the RTCPeerConnection constructor, with transceivers added in M69. History: https://crbug.com/799030. Canary/Dev experiments making Unified Plan the default behavior started in 71. The target is to release Unified Plan by default in 72 Stable. For more information, see https://webrtc.org/web-apis/chrome/unified-plan/.

Last updated on 2021-12-13