Re: [AVTCORE] New Version Notification for draft-wu-avtcore-dynamic-pt-usage-00.txt

Colin Perkins <csp@csperkins.org> Thu, 05 September 2013 13:17 UTC

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From: Colin Perkins <csp@csperkins.org>
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Subject: Re: [AVTCORE] New Version Notification for draft-wu-avtcore-dynamic-pt-usage-00.txt
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Why? You know whether RTP and RTCP are multiplexed or not.

Colin


On 5 Sep 2013, at 14:11, "Roni Even" <ron.even.tlv@gmail.com> wrote:
> Colin,
> One other reason and it would be added is to say that when selecting which pt numbers to use always assume that multiplexing of RTP/RTCP  is used.
> Roni
> 
>> -----Original Message-----
>> From: Colin Perkins [mailto:csp@csperkins.org]
>> Sent: 05 September, 2013 3:28 PM
>> To: Qin Wu
>> Cc: Roni Even; avt@ietf.org
>> Subject: Re: [AVTCORE] New Version Notification for draft-wu-avtcore-
>> dynamic-pt-usage-00.txt
>> 
>> Qin,
>> 
>> On 5 Sep 2013, at 03:42, Qin Wu <bill.wu@huawei.com> wrote:
>>> Hi,Colin:
>>> For motivation, May I point you to look at the following discussion on
>> MMUSIC mailing list:
>>> http://www.ietf.org/mail-archive/web/payload/current/msg00542.html
>>> http://www.ietf.org/mail-archive/web/mmusic/current/msg11062.html
>>> http://www.ietf.org/mail-archive/web/mmusic/current/msg11107.html
>>> 
>>> I don't know it is sufficient to just send some proposed IANA changes to
>> IANA.
>>> Usually based on my understanding, a document is needed to let IANA to
>> take action.
>> 
>> If your goal is simply to correct the registry to match RFC 5761, then I
> don't
>> believe you need a new document. Just email the IANA, and ask them to
>> make the correction to match RFC 5761.
>> 
>>> For your comments, I do think we give a new policy for new payload
> format
>> coming up, please see my reply below.
>> ...
>>> [Qin]: I disagree. just like two policies given in section 4 of RFC5761,
> one
>> new policy we want to give in this draft is since the registry for RTP
> Payload
>> types (PT) for standard audio and video
>>> encodings  is closed, new payload format *MUST*   use dynamic payload
>> type number assignment and Each new payload format is named by a
>> registered media subtype.
>>> 
>>> However RFC3551 section 3.1 only said,to register additional encoding,
> you
>> may either assign each encoding a short name, in some context, you refer
> to
>> these encodings in the form of a MIME content-type, or assigns static RTP
>> payload type numbers, or assign with dynamic payload type number.
>> 
>> I don't understand your message, but I do not believe there is a conflict
>> between RFC 3551 and 5761.
>> 
>>> [Qin]: I see. However one thing I don't understand, RFC5761only
>>> proposes Multiplexing RTP Data and Control Packets on a Single Port, Why
>> two policies defined in RFC5761 can affect RFC3551 and proposed payload
>> type usage can be used to update RFC3551.
>> 
>> Because the payload type in RTP and RTCP packet occupies the same byte,
>> but is 7 bits in RTP and 8 bits in RTCP. When multiplexing RTP and RTCP
>> packets on the same port it is necessary to specify how to distinguish.
> That is
>> the reason why RFC 5761 updates RFC 3551.
>> 
>> 
>> --
>> Colin Perkins
>> http://csperkins.org/
>> 
> 
> 



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