Re: [AVTCORE] I-D Action: draft-ietf-avtcore-rtp-circuit-breakers-09.txt

[Magnus Westerlund <[e-mail]>]

WG,

I have reviewed the changes in this version and like to thank the
authors for the proposal on scaling the reporting interval. I do however
have some feedback.

1. Section 4.5:

The table contains two errors.

A. The CB_interval for Td=5.0 should be 3.

B. All values in the Time to trigger for Td values from 1.0 seconds and
larger is calculated without using the floor function.

2. Section 4.5:

   If the RTP/AVPF profile [RFC4585] or the RTP/SAVPF [RFC5124] is used,
   and the T_rr_interval parameter is used to reduce the frequency of
   regular RTCP reports, then the value Td in the above expression for
   the CB_INTERVAL parameter MUST be replaced by T_rr_interval.

I think that the correct thing to do is to say that for AVPF/SAVPF the
calculation of the CB_Interval shall be done using max(T_rr_interval, Td).


I do hope that other WG participants will review this. The change with
scaling the triggering is a significant change and you should evaluate it.

Cheers

Magnus Westerlund
(As individual)

On 2015-03-06 17:54, [e-mail] wrote:
> 
> A New Internet-Draft is available from the on-line Internet-Drafts directories.
>  This draft is a work item of the Audio/Video Transport Core Maintenance Working Group of the IETF.
> 
>         Title           : Multimedia Congestion Control: Circuit Breakers for Unicast RTP Sessions
>         Authors         : Colin Perkins
>                           Varun Singh
> 	Filename        : draft-ietf-avtcore-rtp-circuit-breakers-09.txt
> 	Pages           : 22
> 	Date            : 2015-03-06
> 
> Abstract:
>    The Real-time Transport Protocol (RTP) is widely used in telephony,
>    video conferencing, and telepresence applications.  Such applications
>    are often run on best-effort UDP/IP networks.  If congestion control
>    is not implemented in the applications, then network congestion will
>    deteriorate the user's multimedia experience.  This document does not
>    propose a congestion control algorithm; instead, it defines a minimal
>    set of RTP "circuit-breakers".  Circuit-breakers are conditions under
>    which an RTP sender needs to stop transmitting media data in order to
>    protect the network from excessive congestion.  It is expected that,
>    in the absence of severe congestion, all RTP applications running on
>    best-effort IP networks will be able to run without triggering these
>    circuit breakers.  Any future RTP congestion control specification
>    will be expected to operate within the constraints defined by these
>    circuit breakers.
> 
> 
> The IETF datatracker status page for this draft is:
> https://datatracker.ietf.org/doc/draft-ietf-avtcore-rtp-circuit-breakers/
> 
> There's also a htmlized version available at:
> http://tools.ietf.org/html/draft-ietf-avtcore-rtp-circuit-breakers-09
> 
> A diff from the previous version is available at:
> http://www.ietf.org/rfcdiff?url2=draft-ietf-avtcore-rtp-circuit-breakers-09
> 
> 
> 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/
> 
> _______________________________________________
> I-D-Announce mailing list
> [e-mail]
> https://www.ietf.org/mailman/listinfo/i-d-announce
> Internet-Draft directories: http://www.ietf.org/shadow.html
> or ftp://ftp.ietf.org/ietf/1shadow-sites.txt
> 
> 


-- 

Magnus Westerlund

----------------------------------------------------------------------
Services, Media and Network features, Ericsson Research EAB/TXM
----------------------------------------------------------------------
Ericsson AB                 | Phone  [phone]
Färögatan 6                 | Mobile [phone]
SE-164 80 Stockholm, Sweden | mailto: [e-mail]
----------------------------------------------------------------------