Vonage Video API Support for Plan B and Unified Plan Session Discovery Protocol


  • Does Vonage Support Unified Plan SDP?
  • Will there be an issue to support Unified Plan SDP as Google Chrome is removing support for Plan B?
  • Any upgrade/ action needed due to the removal of support for Plan B SDP by Google Chrome?


SDP is the mechanism by which endpoints (e.g., client devices, like a phone or laptop) convey information such as the kinds of media supported (e.g., audio and/or video); the media formatsx§ supported (e.g., H264, VP8, etc); and hints on how to establish a connection with it.

When two endpoints want to establish a connection, they share SDPs through a negotiation process.  After negotiation completes, the endpoints have enough information to (attempt to) start sharing media.

In WebRTC, the two most often used dialects are Plan B and Unified Plan. Google Chrome, and Chromium-based browsers like recent versions of Microsoft Edge, use Plan B.  Firefox and Safari use Unified Plan.


Vonage Video has tested interoperability and compatibility with both Plan B on Chrome and Unified Plan in Firefox and Safari. From 24th August 2021, the Google Chrome browser will remove support for the Plan B SDP and support only Unified Plan SDP.

By August 2021, our platform would transition Vonage Video clients in browsers to strictly use Unified Plan. This transition will happen via a patch release to versions 2.18, 2.19, and 2.20 of the web SDK. This should give ample time for developers to ensure that no edge-cases are broken in Chrome’s implementation of Plan B well before the August 24 removal of support. 

Vonage will continue to release bug fixes if required to currently supported client SDKs to ensure maximum compatibility across all uses of the Video Platform. Customers are encouraged to upgrade to the latest patch releases of their SDK. Customers using specific point releases should change configurations to use the latest point release to ensure maximum compatibility. 

Applications using Native clients already are capable of understanding both Plan B and Unified Plan formats, and do so when interacting with Firefox and Safari browsers. Native clients with Chrome and Unified Plan have been tested, and found all currently supported clients (2.17+) to function properly.

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