Request for (Extending) Deprecation Trial: [WebRTC] Deprecate and Remove Plan B

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Henrik Boström

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Nov 18, 2021, 5:57:16 AM11/18/21
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WebRTC is a W3C Recommendation and multiple IETF standards:

Summary
WebRTC is a set of JavaScript API used to send and receive audio, video and data between endpoints. Most Video Conferencing services are built on WebRTC.

In order to set up a connection, the SDP protocol is used. The spec-compliant and cross-browser compatible version of SDP is called "Unified Plan". In contrast, "Plan B" is a non-standard version of SDP only available in Chromium-based browsers using a non-standard API.

"Plan B" was deprecated in M93 Canary but due to high usage, a Deprecation Trial was added, allowing registered websites to make use of "Plan B" until Dec 29, 2021 (a couple of days before the M97 Stable release). See previous intent to experiment/deprecate for more details.

With this request we would like to have an extended Deprecation Trial until May 24, 2022 (M102 Stable Release date).

Blink component
Blink>WebRTC

Search tags
WebRTC SDP Plan B Unified Plan

Interoperability and Compatibility
Unified Plan is shipped-by-default in all major browsers. Plan B, the feature which we are deprecating, it is the one that has interoperability and compatibility risks. UP and PB clients can talk to each other, but in "complex" setups that requires non-trivial SDP translation.


Goals for experimentation
Reduce risk of breakage. Give websites that still depend on Plan B more time to migrate to Unified Plan without delaying the removal for the rest of the web.


Reason this experiment is being extended
When the deprecation announcement was made, "Plan B" was used by the majority of WebRTC Video Conferencing use cases. Today, "Plan B" is used by less than 0.7% of WebRTC use cases. The deprecation is having the desired effect.

However, in order to reduce risk while usage was still high, "Plan B" was only throwing an exception in the Canary release channel as of M93. We are now making "Plan B" throw in Stable for M96, but this has also meant that despite our communication efforts and 1 year time frame, there exists services who discovered the deprecation late and need more time.

By having an extended Deprecation Trial until May 24, 2022, we are providing services that started migration late with enough time to migrate to Unified Plan safely.

Link to entry on the Chrome Platform Status
https://www.chromestatus.com/feature/5823036655665152

Link to previous Intent to Experiment:

Daniel Bratell

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Nov 18, 2021, 11:27:14 AM11/18/21
to Henrik Boström, blink-dev

I'm sure this can be extended, but just a couple of questions.

1. Do you have a link to the usage counter?

2. What feedback have you had during the deprecation /reverse origin trial so far?

/Daniel

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Henrik Boström

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Nov 19, 2021, 3:48:19 AM11/19/21
to blink-dev, Daniel Bratell, Henrik Boström
On Thursday, November 18, 2021 at 5:27:14 PM UTC+1 Daniel Bratell wrote:

I'm sure this can be extended, but just a couple of questions.

1. Do you have a link to the usage counter?

Links from Chrome Platform Status:
According to this data, Plan B usage is this 0.23% of overall WebRTC usage, (Plan B usage / (Plan B + Unified Plan usage)).

Unified Plan usage: 7.497188%
Plan B usage: 0.01732%

Links from UMA pages:
According to this data, Plan B usage is 0.5-0.8% of overall WebRTC usage.

The measure of "complex" SDP, i.e. the type of SDP that has compatibility issues between Unified Plan and Plan B, is 0.5% of overall usage according to UMA:

The overall Plan B usage of the sdpSemantics attribute, regardless of SDP complexity, is 0.8%:


2. What feedback have you had during the deprecation /reverse origin trial so far?


Early in the trial I got feedback that file:// URLs needed to be able to use Plan B because local files cannot sign up for Deprecation Trial, so we made it so that local files can use Plan B during the trial.
In email conversations with affected companies, usually they communicated a timeline and they kept to it, providing no feedback, just migrating successfully without reporting issues.
In one instance a bug was found and communicated via email, and I fixed a couple of bugs filled on crbug before the trial, but I have gotten no reports since ~M93.
I was contacted by one company who was unaware of the deprecation recently, and extending the Deprecation Trial was the result of that exchange.

/Daniel

On 2021-11-18 11:57, Henrik Boström wrote:
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Daniel Bratell

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Nov 19, 2021, 4:47:05 AM11/19/21
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LGTM to extend the reverse origin trial until May 24, 2022 (i.e. approx M102 release date).

Some of the links were not public links, but I think I found them. Looking at timelines, RTCPeerConnectionConstructedWithPlanB has a promising curve, as do the others. The limited feedback combined with the technology switch we do see is also promising. I guess the new code works.

/Daniel

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