IETF Logo Mail Archive

Re: [AVTCORE] Comments ondraft-ietf-avtcore-feedback-supression-rtp-06.txt

Qin Wu <bill.wu@huawei.com> Fri, 16 September 2011 10:31 UTC

Return-Path: <bill.wu@huawei.com>
X-Original-To: avt@ietfa.amsl.com
Delivered-To: avt@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 5E88A21F8B03 for <avt@ietfa.amsl.com>; Fri, 16 Sep 2011 03:31:31 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -5.298
X-Spam-Level:
X-Spam-Status: No, score=-5.298 tagged_above=-999 required=5 tests=[AWL=1.301, BAYES_00=-2.599, RCVD_IN_DNSWL_MED=-4]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id XLRetv4+A+Nd for <avt@ietfa.amsl.com>; Fri, 16 Sep 2011 03:31:30 -0700 (PDT)
Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [119.145.14.66]) by ietfa.amsl.com (Postfix) with ESMTP id 85AA021F8AFE for <avt@ietf.org>; Fri, 16 Sep 2011 03:31:30 -0700 (PDT)
Received: from huawei.com (szxga03-in [172.24.2.9]) by szxga03-in.huawei.com (iPlanet Messaging Server 5.2 HotFix 2.14 (built Aug 8 2006)) with ESMTP id <0LRM006JX2O77F@szxga03-in.huawei.com> for avt@ietf.org; Fri, 16 Sep 2011 18:33:44 +0800 (CST)
Received: from szxrg01-dlp.huawei.com ([172.24.2.119]) by szxga03-in.huawei.com (iPlanet Messaging Server 5.2 HotFix 2.14 (built Aug 8 2006)) with ESMTP id <0LRM0023B2O707@szxga03-in.huawei.com> for avt@ietf.org; Fri, 16 Sep 2011 18:33:43 +0800 (CST)
Received: from szxeml203-edg.china.huawei.com ([172.24.2.119]) by szxrg01-dlp.huawei.com (MOS 4.1.9-GA) with ESMTP id AEA12681; Fri, 16 Sep 2011 18:33:11 +0800
Received: from SZXEML401-HUB.china.huawei.com (10.82.67.31) by szxeml203-edg.china.huawei.com (172.24.2.55) with Microsoft SMTP Server (TLS) id 14.1.270.1; Fri, 16 Sep 2011 18:33:04 +0800
Received: from w53375q (10.138.41.130) by szxeml401-hub.china.huawei.com (10.82.67.31) with Microsoft SMTP Server (TLS) id 14.1.270.1; Fri, 16 Sep 2011 18:33:09 +0800
Date: Fri, 16 Sep 2011 18:33:09 +0800
From: Qin Wu <bill.wu@huawei.com>
X-Originating-IP: [10.138.41.130]
To: "Van Caenegem, Tom (Tom)" <tom.van_caenegem@alcatel-lucent.com>, Magnus Westerlund <magnus.westerlund@ericsson.com>
Message-id: <7C1EF2A3109E4EAB8AD991160AF71AF6@china.huawei.com>
MIME-version: 1.0
X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.6109
X-Mailer: Microsoft Outlook Express 6.00.2900.5931
Content-type: text/plain; charset="iso-8859-1"
Content-transfer-encoding: 7bit
X-Priority: 3
X-MSMail-priority: Normal
X-CFilter-Loop: Reflected
References: <20110831070359.24630.22446.idtracker@ietfa.amsl.com> <4E5F9C23.8050702@ericsson.com> <4E69F7AE.3040601@ericsson.com> <8CD73AC40EDC452A80EE42BBF82E7DE8@china.huawei.com> <4E6E1A90.7050805@ericsson.com> <EC3FD58E75D43A4F8807FDE0749175461918135D@FRMRSSXCHMBSB1.dc-m.alcatel-lucent.com>
Cc: avt@ietf.org, draft-ietf-avtcore-feedback-supression-rtp@tools.ietf.org
Subject: Re: [AVTCORE] Comments ondraft-ietf-avtcore-feedback-supression-rtp-06.txt
X-BeenThere: avt@ietf.org
X-Mailman-Version: 2.1.12
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: <http://www.ietf.org/mail-archive/web/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: Fri, 16 Sep 2011 10:31:31 -0000

Hi, Tom:
Thank for your suggestion. Please see my comments below.
----- Original Message ----- 
From: "Van Caenegem, Tom (Tom)" <tom.van_caenegem@alcatel-lucent.com>
To: "Magnus Westerlund" <magnus.westerlund@ericsson.com>; "Qin Wu" <bill.wu@huawei.com>
Cc: <avt@ietf.org>; <draft-ietf-avtcore-feedback-supression-rtp@tools.ietf.org>
Sent: Tuesday, September 13, 2011 10:11 PM
Subject: RE: [AVTCORE] Comments ondraft-ietf-avtcore-feedback-supression-rtp-06.txt


Magnus,

If you want a view of the RAMS' authors, please check:
http://tools.ietf.org/html/draft-vancaenegem-avtcore-retransmission-for-ssm-00 

I did ask Qin to refer to this draft which provides a detailed description on how feedback suppression can work for RAMS topology.

[Qin]: Okay. I will think about it. 

In summary: 

The BRS sends a NACK or TPLR message to the DS, where the SSRC in this NACK or TPLR message is the one of the BRS. The DS forwards/reflects this message down on the primary SSM. This procedure will allow isolated feedback suppression, when RTP receivers only trigger FB suppression when recognising the SSRC as belonging to the BRS to which they report.

[Qin]: What do you mean about isolated feedback suppression, do you mean DS control which BRS it will redistribute Feedback suppression message from BRS or just flood the message to all the BRSes.

Tom  

> 4. Section 6.2: "If the BRS impacted by packet loss has been told the 
> actual packet loss, the BRS MAY choose to create new Third Party Loss 
> Report message and send it to the receivers in the downstream link.
> "
> 
> I don't understand how the BRS can inject any message into the SSM 
> tree, as the source anchor of the SSM tree is up at the multicast 
> source. Thus a BRS needs to tell the distribution source to send 
> something down stream on its behalf.
> 
> 
> 
> 
> [Qin]: It is possbile for BRS to tell the distrbution source to send 
> TPLR down on its BRS. My question is Is the BRS similar to 
> Distribution source as an intermediary between multicast source and
> 
> downstream receivers? Why BRS can not inject in between while 
> Distribution Source can?

My understanding what that the BRS is in fact not owner of their own SSM session, only help nodes that are receiver of the SSM session but not DS in it. And having the BRS send something to the DS which is only valid for its little part of a large SSM session is strange.

But RAMS authors view would be appreciated.

v2.23.0 | Report a Bug | By Email