Return-Path: X-Original-To: mmusic@ietfa.amsl.com Delivered-To: mmusic@ietfa.amsl.com Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 4A9A5131D12; Wed, 26 Jul 2017 09:30:10 -0700 (PDT) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -1.88 X-Spam-Level: X-Spam-Status: No, score=-1.88 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, HTML_MESSAGE=0.001, RP_MATCHES_RCVD=-0.001, T_SPF_HELO_PERMERROR=0.01, T_SPF_PERMERROR=0.01] autolearn=ham autolearn_force=no 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 8MTNqj0cN9PJ; Wed, 26 Jul 2017 09:30:07 -0700 (PDT) Received: from nostrum.com (raven-v6.nostrum.com [IPv6:2001:470:d:1130::1]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id A85C6131D10; Wed, 26 Jul 2017 09:30:07 -0700 (PDT) Received: from Orochi.local (99-152-146-228.lightspeed.dllstx.sbcglobal.net [99.152.146.228]) (authenticated bits=0) by nostrum.com (8.15.2/8.15.2) with ESMTPSA id v6QGU08Z025788 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NO); Wed, 26 Jul 2017 11:30:01 -0500 (CDT) (envelope-from adam@nostrum.com) X-Authentication-Warning: raven.nostrum.com: Host 99-152-146-228.lightspeed.dllstx.sbcglobal.net [99.152.146.228] claimed to be Orochi.local To: Bernard Aboba , Bo Burman Cc: =?UTF-8?Q?I=c3=b1aki_Baz_Castillo?= , "draft-ietf-mmusic-rid@ietf.org" , "mmusic (mmusic@ietf.org)" , "draft-ietf-mmusic-sdp-simulcast@ietf.org" References: <3A98F0E8-772E-40E3-A872-5414AC8FDF35@iii.ca> <12EA18B8-39F0-491F-92B6-D41F3D640209@iii.ca> From: Adam Roach Message-ID: Date: Wed, 26 Jul 2017 11:29:54 -0500 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/alternative; boundary="------------ED5712AAF60391305E7F1F1B" Content-Language: en-US Archived-At: Subject: Re: [MMUSIC] FW: [rtcweb] How to signal RTX SSRCs with simulcast X-BeenThere: mmusic@ietf.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: Multiparty Multimedia Session Control Working Group List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 26 Jul 2017 16:30:10 -0000 This is a multi-part message in MIME format. --------------ED5712AAF60391305E7F1F1B Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Future-proofness. Recall that the original design here was to give redundancy streams the same ID as the stream they're repairing, but there were objections that doing so would preclude using the mechanism to talk about redundancy streams in SDP if such a need ever arose in the future. So, we allow for signaling of these IDs in SDP, but (since as you correctly point out there are no concrete use cases at the moment) do not require it. You seem to think this is a problem. Can you describe a scenario in which it causes interop issues or additional implementation complexity? /a On 7/26/17 11:21, Bernard Aboba wrote: > Why would a redundancy RTP stream have an "a=rid" line of its own? I > am struggling to find a use case for this. > > On Thu, Jul 6, 2017 at 4:49 AM, Bo Burman > wrote: > > To follow up on this, I suggest making the following addition to > draft-ietf-mmusic-rid: > > ---- AFTER this text in section 4 ---- > > An "a=rid" SDP media attribute specifies restrictions defining a > unique RTP payload configuration identified via the "rid-id" field. > This value binds the restriction to the RTP Stream identified > by its > RTP Stream Identifier SDES item [I-D.ietf-avtext-rid]. To be clear, > implementations that use the "a=rid" parameter in SDP MUST support > the RtpStreamId SDES item described in [I-D.ietf-avtext-rid]. Such > implementations MUST send it for all streams in an SDP media > description ("m=") that have "a=rid" lines remaining after applying > the rules in Section 6 and its subsections. > > ---- ... add this proposed, new text ---- > > Implementations that use the "a=rid" parameter in SDP and that > make use of redundancy RTP streams [RFC7656], e.g. RTP RTX > [RFC4588] or FEC [RFC5109][I-D.ietf-payload-flexible-fec-scheme], > for any of the source RTP streams that have "a=rid" lines remaining > after applying the rules in Section 6 and its subsections, MUST > support and use RepairedRtpStreamId SDES item described in > [I-D.ietf-avtext-rid] for those redundancy RTP streams. This > provides > the binding between the source RTP stream and the corresponding > redundancy RTP stream, by setting RepairedRtpStreamId value for > the redundancy RTP stream to the RtpStreamId value of the source > RTP stream. The redundancy RTP stream MAY (but need not) have an > "a=rid" line of its own, in which case the RtpStreamId SDES > item value > will be different from the corresponding source RTP stream. > > ---- End changes ---- > > The -simulcast draft would be entirely agnostic to this > clarification of "a=rid" and RepairedRtpStreamId usage and thereby > transparently allow using redundancy RTP streams with simulcast. > > /Bo > (as individual) > > > -----Original Message----- > > From: Iñaki Baz Castillo [mailto:ibc@aliax.net > ] > > Sent: den 13 mars 2017 14:43 > > To: Bo Burman > > > Cc: mmusic (mmusic@ietf.org ) > >; Taylor Brandstetter > (deadbeef@google.com ) > > >; > draft-ietf-mmusic-rid@ietf.org > ; > draft-ietf-mmusic-sdp-simulcast@ietf.org > > > Subject: Re: [MMUSIC] FW: [rtcweb] How to signal RTX SSRCs with > simulcast > > > > 2017-03-13 14:41 GMT+01:00 Bo Burman >: > > > [BoB] Usage of RepairedRtpStreamId and RtpStreamId are already > defined on RTP level by -avtext-rid. If we have > > preferences on how to best use them with redundancy RTP streams > in general, I suggest we add text to -mmusic-rid > > about it. This would be regardless if we go for option A or B, > but decided once and for all, thus applicable to RFC 4588 rtx > > and FLEX-FEC alike. > > > > Agreed. > > > > > > -- > > Iñaki Baz Castillo > > > > _______________________________________________ > mmusic mailing list > mmusic@ietf.org > https://www.ietf.org/mailman/listinfo/mmusic > > > --------------ED5712AAF60391305E7F1F1B Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit
Future-proofness.

Recall that the original design here was to give redundancy streams the same ID as the stream they're repairing, but there were objections that doing so would preclude using the mechanism to talk about redundancy streams in SDP if such a need ever arose in the future. So, we allow for signaling of these IDs in SDP, but (since as you correctly point out there are no concrete use cases at the moment) do not require it.

You seem to think this is a problem. Can you describe a scenario in which it causes interop issues or additional implementation complexity?

/a

On 7/26/17 11:21, Bernard Aboba wrote:
Why would a redundancy RTP stream have an "a=rid" line of its own?  I am struggling to find a use case for this. 

On Thu, Jul 6, 2017 at 4:49 AM, Bo Burman <bo.burman@ericsson.com> wrote:
To follow up on this, I suggest making the following addition to draft-ietf-mmusic-rid:

---- AFTER this text in section 4 ----

   An "a=rid" SDP media attribute specifies restrictions defining a
   unique RTP payload configuration identified via the "rid-id" field.
   This value binds the restriction to the RTP Stream identified by its
   RTP Stream Identifier SDES item [I-D.ietf-avtext-rid].  To be clear,
   implementations that use the "a=rid" parameter in SDP MUST support
   the RtpStreamId SDES item described in [I-D.ietf-avtext-rid].  Such
   implementations MUST send it for all streams in an SDP media
   description ("m=") that have "a=rid" lines remaining after applying
   the rules in Section 6 and its subsections.

---- ... add this proposed, new text ----

   Implementations that use the "a=rid" parameter in SDP and that
   make use of redundancy RTP streams [RFC7656], e.g. RTP RTX
   [RFC4588] or FEC [RFC5109][I-D.ietf-payload-flexible-fec-scheme],
   for any of the source RTP streams that have "a=rid" lines remaining
   after applying the rules in Section 6 and its subsections, MUST
   support and use RepairedRtpStreamId SDES item described in
   [I-D.ietf-avtext-rid] for those redundancy RTP streams. This provides
   the binding between the source RTP stream and the corresponding
   redundancy RTP stream, by setting RepairedRtpStreamId value for
   the redundancy RTP stream to the RtpStreamId value of the source
   RTP stream. The redundancy RTP stream MAY (but need not) have an
   "a=rid" line of its own, in which case the RtpStreamId SDES item value
   will be different from the corresponding source RTP stream.

---- End changes ----

The -simulcast draft would be entirely agnostic to this clarification of "a=rid" and RepairedRtpStreamId usage and thereby transparently allow using redundancy RTP streams with simulcast.

/Bo
(as individual)

> -----Original Message-----
> From: Iñaki Baz Castillo [mailto:ibc@aliax.net]
> Sent: den 13 mars 2017 14:43
> To: Bo Burman <bo.burman@ericsson.com>
> Cc: mmusic (mmusic@ietf.org) <mmusic@ietf.org>; Taylor Brandstetter (deadbeef@google.com)
> <deadbeef@google.com>; draft-ietf-mmusic-rid@ietf.org; draft-ietf-mmusic-sdp-simulcast@ietf.org
> Subject: Re: [MMUSIC] FW: [rtcweb] How to signal RTX SSRCs with simulcast
>
> 2017-03-13 14:41 GMT+01:00 Bo Burman <bo.burman@ericsson.com>:
> > [BoB] Usage of RepairedRtpStreamId and RtpStreamId are already defined on RTP level by -avtext-rid. If we have
> preferences on how to best use them with redundancy RTP streams in general, I suggest we add text to -mmusic-rid
> about it. This would be regardless if we go for option A or B, but decided once and for all, thus applicable to RFC 4588 rtx
> and FLEX-FEC alike.
>
> Agreed.
>
>
> --
> Iñaki Baz Castillo
> <ibc@aliax.net>
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