Subject: Default Stream Number For Audio

From: Tom-PT Taylor <[email-masked]>
Date: Fri, 3 Sep 1999 14:35:08 -0500

We currently have two forms of the stream portion of media descriptor for a
termination:

   stream = (streamParms / streamList)

   streamList = streamDescriptor *(COMMA streamDescriptor)

   streamDescriptor = StreamToken EQUAL StreamID
                                       LBRKT streamParms RBRKT

In other words, the form is either
  localDescriptor, remoteDescriptor, localControlDescriptor
or a list of stream entries of the form
  "Stream" "="
      <StreamID> {localDescriptor, remoteDescriptor, localControlDescriptor}

The real intent of keeping the first form is to simplify the syntax for the
audio-only case.

There is a theoretical possibility that terminations configured with the
first form could become involved in associations where some of the
terminations are described using the form involving explicit StreamID
values.  To make this as simple as possible, I would propose that we have
default StreamID values at least for audio, and possibly also for other
media.  I propose the following defaults (using the medium types defined in
RFC 2327):

    Medium          Default StreamID

    Control                      0
    Audio                        1
    Video                        2
    Application                3

H.323 people will recognize the consistency between these proposals and the
recommended logical channel number assignments in H.323.

Tom Taylor
Advisor -- IPConnect Standards
E-mail: [email-masked] (internally, Tom-PT Taylor)
Phone and FAX: +1 613 736 0961

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From: Paul Sijben <[email-masked]>
Date: Wed, 8 Sep 1999 11:01:29 +0200

Tom,

this seems like a sensible approach for the simple cases.
Do you have an idea how you want to handle multiple streams of the same
media type?

Browsing through the latest syntax description I could not find a way to
explicitly describe the type of a stream. Of course this can be partially
be deduced from the media properties (so encoding etc.). If this is the way
we want to do it, we are probably going to need to text to that respect.

Paul

--
Paul Sijben              Tel:+31 35 687 4774
Lucent Technologies      Fax:+31 35 687 5954
Forward Looking Work     mailto:[email-masked]
Huizen, The Netherlands  http://voip.nl.lucent.com/sijben (internal)