Re: [rmcat] I-D Action: draft-ietf-rmcat-cc-codec-interactions-01.txt

[Karen Elisabeth Egede Nielsen <[e-mail]>]

Hi,

Please accept the following comments to the new document.
Use as you see fit.

General Comments:

* The document describes both a conceptual model for the various
interactions as well as the
particular details of the codec-cc interactions. Perhaps this is as it
should be, but I am still not really sure about
that this conceptual model belongs in this document. Anyway it is necessary
to have it somewhere.

* The document in details refer to interaction with FEC, but FEC is not put
in place in the conceptual model.
I think the conceptual model, if it should be here, should make reference to
where FEC functions logical reside (in codec or outside of codec..).

Detailed comments:

* Section 5: First paragraph should be revised. This section includes
optional as well as mandatory (necessary) requirements.

* Section 5.1:

Not sure what the following statement is intended to say - This sounds like
requirements for the CC or requirements for the codecs to apply on top of
the rate provided from the CC ?

"The rate must never exceed permanent limits established in
   session signaling such as the SDP bandwidth attribute [RFC4566] nor
   temporary limits in RTCP such as TMMBR [RFC5104] or REMB
   [I-D.alvestrand-rmcat-remb]. "

*Section 5.2.3:

"Note this is unrecoverable post-repair loss after
   retransmission or forward error correction."

Is it assumed that the CC would have this intelligence to distinguish
post-repair loss from loss ?

* Section 5.2.4

Is it considered likely that the CC could do anything to differentiate on
random versus periodic versus consecutive losses ?

Is section 5.2.5 not special FEC consideration of 5.2.4 ?

* Section 5.2.6:  So this interaction is CC <-- --> FEC - or ?

Some comments given to  draft-zanaty-rmcat-cc-codec-interactions-00, email
of July 19'th, also apply to this draft.

BR, Karen


> -----Original Message-----
> From: rmcat [mailto:[e-mail]] On Behalf Of internet-
> [e-mail]
> Sent: 18. oktober 2015 17:30
> To: [e-mail]
> Cc: [e-mail]
> Subject: [rmcat] I-D Action: draft-ietf-rmcat-cc-codec-interactions-01.txt
>
>
> A New Internet-Draft is available from the on-line Internet-Drafts
> directories.
>  This draft is a work item of the RTP Media Congestion Avoidance
> Techniques
> Working Group of the IETF.
>
>         Title           : Congestion Control and Codec interactions in RTP
> Applications
>         Authors         : Mo Zanaty
>                           Varun Singh
>                           Suhas Nandakumar
>                           Ericsson AB
> 	Filename        : draft-ietf-rmcat-cc-codec-interactions-01.txt
> 	Pages           : 12
> 	Date            : 2015-10-18
>
> Abstract:
>    Interactive real-time media applications that use the Real-time
>    Transport Protocol (RTP) over the User Datagram Protocol (UDP) must
>    use congestion control techniques above the UDP layer since it
>    provides none.  This memo describes the interactions and conceptual
>    interfaces necessary between the application components that relate
>    to congestion control, specifically the media codec control layer,
>    and the components dedicated to congestion control functions.
>
>
> The IETF datatracker status page for this draft is:
> https://datatracker.ietf.org/doc/draft-ietf-rmcat-cc-codec-interactions/
>
> There's also a htmlized version available at:
> https://tools.ietf.org/html/draft-ietf-rmcat-cc-codec-interactions-01
>
> A diff from the previous version is available at:
> https://www.ietf.org/rfcdiff?url2=draft-ietf-rmcat-cc-codec-interactions-01
>
>
> Please note that it may take a couple of minutes from the time of
> submission
> until the htmlized version and diff are available at tools.ietf.org.
>
> Internet-Drafts are also available by anonymous FTP at:
> ftp://ftp.ietf.org/internet-drafts/