Subject: [avtext] Mirja Kühlewind's No Objection on draft-ietf-avtext-sdes-hdr-ext-05: (with COMMENT)

From: "Mirja Kuehlewind" <[email-masked]>
Date: Tue, 26 Apr 2016 05:55:13 -0700

Mirja Kühlewind has entered the following ballot position for
draft-ietf-avtext-sdes-hdr-ext-05: No Objection

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COMMENT:
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This is a very clear and well written doc. Thanks. Two minor comments:

1) The calculation for the number of transmission N seems slightly
over-complicated: "N is selected so that the header extension target
delivery probability reaches 1-P^N, where P is the probability of packet
loss." Does a new participant already know the loss probably e.g. at the
time of joining? Is it correct that if it is assumed to be p=0 that one
will send the extension header only once? Should there be a minimum...?

2) Should this doc also register MID?

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From: Magnus Westerlund <[email-masked]>
Date: Tue, 26 Apr 2016 15:30:23 +0200

> https://datatracker.ietf.org/doc/draft-ietf-avtext-sdes-hdr-ext/

So a new one may not know the probability of losses. But, assuming an 
active session a participant should have some data for the session quite 
rapidly, within a couple of RTCP reporting intervals. What could be done 
it to recommend a default value. However, we have to remember that a 
single transmission might be a very reasonable choice for scenarios with 
low loss probabilities, as one anyway have RTCP as the backup mechanism.

Additional feedback is appreciated here.

> 2) Should this doc also register MID?

Nope, as this document now has overtaken 
https://datatracker.ietf.org/doc/draft-ietf-mmusic-sdp-bundle-negotiation/ 
it will be BUNDLE that has to define the registration. Initially we 
thought that BUNDLE would be done, and we would catch up and have to 
move the registration, but that didn't happen.

Cheers

Magnus Westerlund

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From: "Mirja Kuehlewind (IETF)" <[email-masked]>
Date: Tue, 26 Apr 2016 16:10:45 +0200

Hi Magnus,

see below.

> Am 26.04.2016 um 15:30 schrieb Magnus Westerlund <[email-masked]>:
> 
> So a new one may not know the probability of losses. But, assuming an active session a participant should have some data for the session quite rapidly, within a couple of RTCP reporting intervals. What could be done it to recommend a default value. However, we have to remember that a single transmission might be a very reasonable choice for scenarios with low loss probabilities, as one anyway have RTCP as the backup mechanism.
> 

I don’t have a good proposal here. I mainly wanted to make sure that 1 is an acceptable value. I think it’s okay to leave it as it is.

> Nope, as this document now has overtaken https://datatracker.ietf.org/doc/draft-ietf-mmusic-sdp-bundle-negotiation/ it will be BUNDLE that has to define the registration. Initially we thought that BUNDLE would be done, and we would catch up and have to move the registration, but that didn't happen.

Okay. Didn’t see that it also defines the RTP extension. That’s fine.

Thanks,
Mirja