Subject: [MMUSIC] Updated draft: draft-alvestrand-one-rtp-02

From: Harald Alvestrand <[email-masked]>
Date: Wed, 28 Sep 2011 17:43:43 +0200

One of our people is implementing this draft, and came up with an issue 
of language: It was not clear to him what "first" meant in the context 
of the draft.
I found it best to issue a new version to address the issue (choosing to 
have the first section mentioned on the TOGETHER line as "first").

I took the opportunity to update a couple of other points, and to 
reiterate the point that this draft is intending to increase the 
expressive power of describing one RTP session, NOT as a proposal for 
multiplexing RTP sessions; the confusion on this point seems to be 
bedeviling  every discussion we have on this matter.

I also adopted the "same origin port" from draft-holmberg, since the 
consensus of mmusic seemed to be that this is a less harmful proposal 
than the one I originally had in my draft.

Enjoy!

                         Harald

---

From: "Dan Wing" <[email-masked]>
Date: Wed, 28 Sep 2011 18:51:05 -0700

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] On
> Behalf Of Harald Alvestrand
> Sent: Wednesday, September 28, 2011 8:44 AM
> To: mmusic
> Subject: [MMUSIC] Updated draft: draft-alvestrand-one-rtp-02
> 

I don't find the string "same origin port", or even "origin\b", 
appearing in any draft-holmberg*.

Is there a reason to avoid the term "Symmetric RTP", defined in 
RFC4961, http://tools.ietf.org/html/rfc4961,

<quote>
   A device supports symmetric RTP if it selects, communicates, and uses
   IP addresses and port numbers such that, when receiving a
   bidirectional RTP media stream on UDP port "A" and IP address "a", it
   also transmits RTP media for that stream from the same source UDP
   port "A" and IP address "a".  That is, it uses the same UDP port to
   transmit and receive one RTP stream.
</quote>

-d

> Enjoy!
> 
>                          Harald
> 
> _______________________________________________
> mmusic mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/mmusic

---

From: Harald Alvestrand <[email-masked]>
Date: Thu, 29 Sep 2011 09:53:41 +0200

> appearing in any draft-holmberg*.
sorry for not being more precise....

draft-holmberg-mmusic-sdp-multiplex-negotiation-00

5.2.  SDP Offerer Procedures

    When an SDP offerer wants to offer multiplexed media, it inserts the
    same port number value for each "m=" line that is part of the offered
    multiplex.  In addition, the SDP offerer inserts an SDP session-level
    "a=group" attribute, with a "MULTIPLEX" value, and assigns an SDP
    media-level "a=mid" attribute value for each "m=" line that is part
    of the offered multiplex.

I hope that I can merge my draft with draft-holmberg eventually, but we 
seem to have met a bit of a language problem when using the word 
"multiplex" - its (lack of) exact meaning has been bedeviling so many of 
these discussions that I'm beginning to dislike, detest and abhor the word.

>     transmit and receive one RTP stream.
That's a very good reference to add. Since the TOGETHER draft (and 
Holmberg's MULTIPEX draft) assumes that you can identify an RTP session 
by a 5-tuple, it has to assume that support for symmetric RTP is present.

Thanks!

---

From: "Dan Wing" <[email-masked]>
Date: Thu, 29 Sep 2011 08:17:23 -0700

> From: Harald Alvestrand [mailto:[email-masked]]
> Sent: Thursday, September 29, 2011 12:54 AM
> To: Dan Wing
> Cc: 'mmusic'
> Subject: Re: [MMUSIC] Updated draft: draft-alvestrand-one-rtp-02
> 
> >> I found it best to issue a new version to address the issue
> (choosing
> >> to

It's probably worth considering a concise definition of "multiplex" 
in a standalone document, like we had to do for the definition 
of Symmetric RTP.  If not "multiplex", we can always invent a new
term, like "jefkie" (a random set of keys that I pressed).

> by a 5-tuple, it has to assume that support for symmetric RTP is

Sure.
-d

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From: "Kevin P. Fleming" <[email-masked]>
Date: Thu, 29 Sep 2011 11:33:08 -0500

> term, like "jefkie" (a random set of keys that I pressed).

Since 'combobulate' gets nearly no usage compared to 'discombobulate', 
I'd vote for that :-)

-- 
Kevin P. Fleming
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