Re: [rtcweb] data channel protocol comments and potential agenda topic

["Ejzak, Richard P (Richard)" <[e-mail]>]

I don't see any conflict between our positions, Harald.  You are arguing that we need a generic data transfer capability that can be used by any application for any purpose, which can be achieved by specifying raw data transfer, and I fully support this.  I am arguing that it would be advantageous to be able to have the option to specify an underlying protocol on a data channel so that we can develop interoperable applications.  These capabilities are not mutually exclusive.

An example might be MSRP.  If we would like to use MSRP between endpoints then we could specify that browsers need to support MSRP natively and specify a new API to access it.  Or we could allow an application to send MSRP over a data channel without impacting the browser.  This would potentially allow browsers running different communications applications to use MSRP in addition to audio and video media for communication, even if other application specific uses of data channel are not interoperable.

I'm not arguing that we should standardize MSRP over data channel - just that this approach gives us the potential to define interoperable data channel applications in the future.

It would also be a good idea to reserve a range of ppid values for proprietary use.  Then when two browsers are communicating with the same application, the application can signal the purpose behind a new block of data with the choice of proprietary ppid value.  An application might use one value to signal gaming control information and another value to signal display information.  This approach would save a typical application from exchanging signaling just to set up channels so that it can begin to use them.