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Re: [AVT] Liaison from SMPTE re RFC 5109



Colin Perkins skrev:
We've received the attached liaison statement from SMPTE regarding the non-backwards compatible nature of RFC 5109 FEC (which obsoletes RFC 2733), and the problems this is causing with SMPTE 2022-1. Comments are solicited (to the list, or privately to the chairs), so we can make a response reflecting working group consensus.


As an individual!

To my knowledge (based on memory) the so call RFC 2733 version that SMPTE has defined in SMPTE 2022-1 is no more compatible with RFC 2733 than RFC 5109. SMPTE redefines which packets that got XOR, while RFC 5109 has a different data structure to perform the XOR over. Independently, you need to implement the specific mechanism you are using. As I can't get the document now, I wonder if the signalling of their extension is clear enough. That is something to look into.

I would suggest that we respond that we understand their choice but point out the reasons why we changed what data was included and in which way. That is also the answer why we don't intended to take any larger consideration into the growing use of RFC 2733. As we find it troubling that the mistake in using non-generalized packet processing that RFC 2733 resulted in is getting wide spread usage instead of the corrected one.

Cheers

Magnus Westerlund

IETF Transport Area Director & TSVWG Chair
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Multimedia Technologies, Ericsson Research EAB/TVM
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Ericsson AB                | Phone +46 8 4048287
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S-164 80 Stockholm, Sweden | mailto: magnus.westerlund at ericsson.com
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