Re: [MMUSIC] IANA registration of SDP attributes

Flemming Andreasen <> Tue, 05 April 2016 02:29 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id 46E9712D093 for <>; Mon, 4 Apr 2016 19:29:00 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -14.531
X-Spam-Status: No, score=-14.531 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_HI=-5, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_PASS=-0.001, T_RP_MATCHES_RCVD=-0.01, USER_IN_DEF_DKIM_WL=-7.5] autolearn=ham autolearn_force=no
Authentication-Results: (amavisd-new); dkim=pass (1024-bit key)
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id OTAiJN__iizB for <>; Mon, 4 Apr 2016 19:28:58 -0700 (PDT)
Received: from ( []) (using TLSv1.2 with cipher DHE-RSA-SEED-SHA (128/128 bits)) (No client certificate requested) by (Postfix) with ESMTPS id A68C812D0F0 for <>; Mon, 4 Apr 2016 19:28:58 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple;;; l=2471; q=dns/txt; s=iport; t=1459823338; x=1461032938; h=subject:to:references:from:message-id:date:mime-version: in-reply-to:content-transfer-encoding; bh=GwBQu9/D/PRmzpNSBvGDjqjReVvLzo0dSfOx+/UDHbU=; b=Mcx05HUpIzCwbxpYEgY/4pkNfjcoHFbdvJmLnqd/auTTbZOpB5WGQpdA imcnRgNhLeAC9y8iulwSto1xaAopwmZVgA1Q0HqI1PGZnfIPxfGrxlmK+ nt8HHzRG2hbp3CkTol4wu+0kv+ofNlq68Mcb2oOGZjmYMQpnyBjoqGf1E 0=;
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: =?us-ascii?q?A0AqAgDHIgNX/4YNJK1dDoMpummCDwENg?= =?us-ascii?q?XKGDQKBNDgUAQEBAQEBAWUnhEEBAQEDATgzBwYGCwsOCgkWDwkDAgECAUUGAQw?= =?us-ascii?q?IAQGIGwi/DgEBAQEBAQEBAQEBAQEBAQEahiCESooVAQSYAYtRgjeBaBeENoMFh?= =?us-ascii?q?VWGGokAHgEBQoMsVyCIVgEBAQ?=
X-IronPort-AV: E=Sophos;i="5.24,442,1454976000"; d="scan'208";a="257579311"
Received: from ([]) by with ESMTP/TLS/DHE-RSA-AES256-SHA; 05 Apr 2016 02:28:35 +0000
Received: from [] ( []) by (8.14.5/8.14.5) with ESMTP id u352SXR9002556; Tue, 5 Apr 2016 02:28:34 GMT
To: Paul Kyzivat <>,
References: <> <> <> <> <> <> <> <> <> <>
From: Flemming Andreasen <>
Message-ID: <>
Date: Mon, 4 Apr 2016 22:28:32 -0400
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:38.0) Gecko/20100101 Thunderbird/38.7.0
MIME-Version: 1.0
In-Reply-To: <>
Content-Type: text/plain; charset=windows-1252; format=flowed
Content-Transfer-Encoding: 7bit
Archived-At: <>
Subject: Re: [MMUSIC] IANA registration of SDP attributes
X-Mailman-Version: 2.1.17
Precedence: list
List-Id: Multiparty Multimedia Session Control Working Group <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Tue, 05 Apr 2016 02:29:00 -0000

On 3/29/16 1:48 PM, Paul Kyzivat wrote:
> On 3/29/16 1:28 AM, Christian Groves wrote:
>> Hello Paul,
>> Please see below.
>> Regards, Christian
>> On 24/03/2016 8:59 AM, Paul Kyzivat wrote:
>>> On 3/22/16 3:11 PM, Flemming Andreasen wrote:
>>>> Do we have a volunteer to drive the discussion there ?
>>> OK. I'll volunteer.
>>> The starting point for this discussion is the current text of section
>>> 8.2.4 of rfc4566bis-16.
>>> Looking at that, one thing leaps out at me:
>>> There is a long list of "stuff" that must be provided when defining a
>>> new attribute. IMO it is all *good* stuff, that should be provided.
>>> But it also strikes me that it will be difficult for IANA to evaluate
>>> the adequacy of this stuff itself. So we might want to require an
>>> expert review as a gate to registration.
>> [CNG] What's the role of the SDP directorate in relation to this? I
>> guess they would check any RFC defined attributes but that non-RFCs
>> would also need to be checked? How much of this should be visible on the
>> IANA registry page?
> The SDP directorate will only be invoked for ietf documents. The 
> policy for attributes is Specification Required, so it might be a 
> document from another SDO, ore even no SDO. In those cases there would 
> be no SDP directorate review.
> After refreshing my memory about the definition of Specification 
> Required, I see that it implies Expert Review. (Flemming is currently 
> listed as the expert.) 
Right - I'm currently the designated expert and hence review all 
external registration requests (i.e. from outside IETF).

> That may be good enough, though we might want to beef up the 
> requirements in section 8.2.4 of 4566bis.
> The hard part is seeing to any new actions when *existing* attributes 
> are used in new ways. For that I think the SDP Directorate is all we 
> have to check for that sort of thing. I wonder if there ought to be a 
> checklist of things for SDP Directorate reviews.
There probably should, but it shouldn't be any different than for any 
other SDP extension (syntactic and/or semantic) and hence we should have 
that in 4566bis.

> And of course *that* also will only work for IETF documents. If 
> somebody outside the IETF defines a new use for an existing attribute 
> then we have no mechanism to notice that and trigger an update to the 
> registry.

-- Flemming