IETF Logo Mail Archive

Re: [AVTCORE] AD review: draft-ietf-avtcore-clksrc-09

Aidan Williams <aidan.williams@audinate.com> Wed, 29 January 2014 00:20 UTC

Return-Path: <aidan.williams@audinate.com>
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 E66181A0467 for <avt@ietfa.amsl.com>; Tue, 28 Jan 2014 16:20:03 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.436
X-Spam-Level:
X-Spam-Status: No, score=-2.436 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, HTML_MESSAGE=0.001, RP_MATCHES_RCVD=-0.535, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001] 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 AiaQGyIuNQ7k for <avt@ietfa.amsl.com>; Tue, 28 Jan 2014 16:20:01 -0800 (PST)
Received: from zimbra8.audinate.com (sydney.audinate.com [150.101.200.21]) by ietfa.amsl.com (Postfix) with ESMTP id 87ED31A043A for <avt@ietf.org>; Tue, 28 Jan 2014 16:20:01 -0800 (PST)
Received: from localhost (localhost [127.0.0.1]) by zimbra8.audinate.com (Postfix) with ESMTP id 19B2A343BB3; Wed, 29 Jan 2014 11:19:58 +1100 (EST)
Received: from zimbra8.audinate.com ([127.0.0.1]) by localhost (zimbra8.audinate.com [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id ghdiOLpGmJcC; Wed, 29 Jan 2014 11:19:57 +1100 (EST)
Received: from localhost (localhost [127.0.0.1]) by zimbra8.audinate.com (Postfix) with ESMTP id ECC57343BAE; Wed, 29 Jan 2014 11:19:56 +1100 (EST)
X-Virus-Scanned: amavisd-new at audinate.com
Received: from zimbra8.audinate.com ([127.0.0.1]) by localhost (zimbra8.audinate.com [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id JQDaByk0mxKz; Wed, 29 Jan 2014 11:19:56 +1100 (EST)
Received: from zimbra8.audinate.com (zimbra8.audinate.com [10.12.0.4]) by zimbra8.audinate.com (Postfix) with ESMTP id D1A16343BA9; Wed, 29 Jan 2014 11:19:56 +1100 (EST)
Date: Wed, 29 Jan 2014 11:19:56 +1100
From: Aidan Williams <aidan.williams@audinate.com>
To: Richard Barnes <rlb@ipv.sx>
Message-ID: <134045964.59704.1390954796756.JavaMail.zimbra@audinate.com>
In-Reply-To: <CAL02cgT1=miDLUj3Rt7YT3owFEnzsw2RBiFaau6F6=yB9N=ymw@mail.gmail.com>
References: <CAL02cgT1=miDLUj3Rt7YT3owFEnzsw2RBiFaau6F6=yB9N=ymw@mail.gmail.com>
MIME-Version: 1.0
Content-Type: multipart/alternative; boundary="----=_Part_59703_260793013.1390954796755"
X-Mailer: Zimbra 8.0.6_GA_5922 (ZimbraWebClient - FF26 (Mac)/8.0.6_GA_5922)
Thread-Topic: AD review: draft-ietf-avtcore-clksrc-09
Thread-Index: wkzY8AZpfPMItOp29AexvYG0fg6PZA==
Cc: "avt@ietf.org WG" <avt@ietf.org>
Subject: Re: [AVTCORE] AD review: draft-ietf-avtcore-clksrc-09
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: <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: Wed, 29 Jan 2014 00:20:04 -0000

Hi Richard, 

Thanks for the review. Responses are inline below... 

----- Original Message -----

| From: "Richard Barnes" <rlb@ipv.sx>
| To: "avt@ietf.org WG" <avt@ietf.org>
| Sent: Sunday, 29 December, 2013 12:25:39 PM
| Subject: [AVTCORE] AD review: draft-ietf-avtcore-clksrc-09

| I have reviewed this document in preparation for IETF LC. Overall, it reads
| quite well. Thanks! I have requested a LC.

| A couple of comments that you can consider with LC comments:

| -- It seems like a reader familiar with
| draft-ietf-avtext-rtp-grouping-taxonomy might be surprised by these terms.
| Given that that document is still in development, I don't expect you to be
| able to use the terms there. However, it might be helpful to add a note
| saying that you are not attempting to align with their terminology.

It is great that there is a document attempting to define terminology clearly (it would have been awesome to have it for this draft!), but I'm not sure how to go about addressing your comment since we probably don't want to refer to the above draft explicitly. At present, there is a positive statement: "here are the definitions". Can you say a bit more about what you would like to see? 

| -- GLONASS?

Happy to add this. 

| -- Behavior with traceable clocks seems underspecified to me. Section 4.7
| should say explicitly that traceable clocks are marked with the ":traceable"
| suffix or the "/traceable/" identifier. With regard to NTP/PTP servers, how
| does the user of the clock know that the server is traceable? Is this
| indicated in-band to those protocols? Would it not be useful to be able to
| indicate that those servers provide traceable time?

Marking a clock as traceable allows additional information (e.g. IP addresses, PTP master identifiers and the like) to be omitted from the SDP since any traceable clock available at the answerer is considered to be an appropriate timestamp reference clock. For example, an offerer could could specify ts-refclk:ntp=/traceable/ and the answerer could use GPS as a reference clock since GPS is a source of traceable time. 

Would some additional sentences such as these address your comment? 

regards 
aidan 
____ 
:wq! 

| --Richard

| _______________________________________________
| Audio/Video Transport Core Maintenance
| avt@ietf.org
| https://www.ietf.org/mailman/listinfo/avt

v2.23.0 | Report a Bug | By Email