Re: [AVT] WGLC comments on draft-ietf-avt-ports-for-ucast-mcast-rtp-11: Part 6: Resend behavior

[Magnus Westerlund <[e-mail]>]

Ali C. Begen (abegen) skrev 2011-01-17 14:24:
> OK, I see your concern, however, should not we still follow 4585 as it is and once it gets updated, it will be reflected here? If the immediate mode is chosen, the NACK/RAMS could result in many more spurious transmissions whereas the token stuff only results in one such transmission. So putting some extra rules here for the tokens only will not get us much.
> 
> Maybe, we can add some text to disallow the immediate mode?

You seem to be punting on this issue. I think Immediate mode needs to be
allowed, it makes all the sense for these type of applications in
certain environments. However, what is needed is a separation of the
"packet loss" / "failure for server to act on event" detection mechanism
and the RTCP transmission rate limiting.

I think despite our discussion of these things in CCM (RFC 5104) we did
fail to take all the AVPF cases into account. I have to say that 3.5.1.1
do rely on repeating FIR messages until you get an result. It does fail
to say in which mode and what type of transmission should be used for
the repetitions. This as one in early mode, this is either classified as
an event that are allowed to send early, or as a regular transmission.

There need to be some sanity checking in this, and going forward being
aware that what we specify can be seriously broken is not the best
thing. In addition RAMS can be fixed. And the NACK still doesn't have a
spec for this use case.


Cheers

Magnus Westerlund

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