Re: [AVTCORE] I-D Action: draft-ietf-avtcore-rtp-circuit-breakers-11.txt

Colin Perkins <csp@csperkins.org> Mon, 19 October 2015 10:17 UTC

Return-Path: <csp@csperkins.org>
X-Original-To: avt@ietfa.amsl.com
Delivered-To: avt@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 628531A8892 for <avt@ietfa.amsl.com>; Mon, 19 Oct 2015 03:17:35 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.9
X-Spam-Level:
X-Spam-Status: No, score=-1.9 tagged_above=-999 required=5 tests=[BAYES_00=-1.9] autolearn=ham
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id P_b3gGhFMtP8 for <avt@ietfa.amsl.com>; Mon, 19 Oct 2015 03:17:33 -0700 (PDT)
Received: from balrog.mythic-beasts.com (balrog.mythic-beasts.com [IPv6:2a00:1098:0:82:1000:0:2:1]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 771931A8855 for <avt@ietf.org>; Mon, 19 Oct 2015 03:17:33 -0700 (PDT)
Received: from [130.209.247.112] (port=52152 helo=mangole.dcs.gla.ac.uk) by balrog.mythic-beasts.com with esmtpsa (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.80) (envelope-from <csp@csperkins.org>) id 1Zo7VR-0006E3-97 for avt@ietf.org; Mon, 19 Oct 2015 11:17:31 +0100
Content-Type: text/plain; charset=utf-8
Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2104\))
From: Colin Perkins <csp@csperkins.org>
In-Reply-To: <20151016163008.19060.46684.idtracker@ietfa.amsl.com>
Date: Mon, 19 Oct 2015 11:17:26 +0100
Content-Transfer-Encoding: quoted-printable
Message-Id: <F4657EE8-FA1F-48D9-B5D4-DA4B4BDDDC21@csperkins.org>
References: <20151016163008.19060.46684.idtracker@ietfa.amsl.com>
To: "avt@ietf.org WG" <avt@ietf.org>
X-Mailer: Apple Mail (2.2104)
X-BlackCat-Spam-Score: -28
X-Mythic-Debug: Threshold = On =
Archived-At: <http://mailarchive.ietf.org/arch/msg/avt/jY_bHs6GN5i5ZYzqc1YxBvP-XmM>
Subject: Re: [AVTCORE] I-D Action: draft-ietf-avtcore-rtp-circuit-breakers-11.txt
X-BeenThere: avt@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: Audio/Video Transport Core Maintenance <avt.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/avt>, <mailto:avt-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/avt/>
List-Post: <mailto:avt@ietf.org>
List-Help: <mailto:avt-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/avt>, <mailto:avt-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 19 Oct 2015 10:17:35 -0000

> On 16 Oct 2015, at 17:30, Internet-Drafts@ietf.org 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-11.txt
> 	Pages           : 23
> 	Date            : 2015-10-16
> 
> 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:
> https://tools.ietf.org/html/draft-ietf-avtcore-rtp-circuit-breakers-11
> 
> A diff from the previous version is available at:
> https://www.ietf.org/rfcdiff?url2=draft-ietf-avtcore-rtp-circuit-breakers-11

This version of the draft is a major update, that makes the following changes:

- Update the media timeout circuit breaker to address the over- and under-sampling issues raised by Magnus Westerlund, by taking into account the RTT and RTP framing interval in the calculation, as well as the RTCP reporting interval.

- Update the congestion circuit breaker to address the over- and under-sampling issues raised by Magnus Westerlund, and to account for codecs that cannot change their rate on each frame, by modifying the definition of CB_INTERVAL to include the RTP framing interval, the frame group size, and the RTT in the calculation, as well as the RTCP reporting interval.

- Collect definitions and clarify terminology.

- Clarify behaviour when interworking with systems that don’t implement RTCP, based on feedback by Simon Perreault.

- Remove discussion on Impact of RTCP Reporting Groups, that seemed to confuse rather than clarify.

- Various editorial fixes to address other review comments by Simon Perreault, and make assorted other corrections. 

Feedback welcome. 

Colin




-- 
Colin Perkins
https://csperkins.org/