Subject: MMUSIC meeting in San Diego

From: Joerg Ott <[email-masked]>
Date: Thu, 23 Nov 2000 23:19:25 +0100

Folks,

the MMUSIC WG is scheduled to meet twice at the 49th IETF in San Diego:

    Wednesday, 13 Dec, 1300-1500
    Thursday,  14 Dec, 1530-1730

We would like to solicit input on agenda items for these two meetings.
Please address slot requests to [email-masked] and [email-masked].

A core issue for this meeting will be the further development of SDP
and SDPng.

Colin and Joerg

---

From: Flemming Andreasen <[email-masked]>
Date: Fri, 24 Nov 2000 10:53:31 +0100

I've submitted a draft on adding some simple capability negotiation
capabilites to SDP
(http://search.ietf.org/internet-drafts/draft-andreasen-mmusic-sdp-simcap-00.txt)
which I solicit input on and would like to present in the meeting.

The premise of this draft is that we have a pressing need for a capability
negotiation mechanism. While work on SDPng has begun, it is still at a
somewhat early stage, and given that SDPng is anticipated to not be
backwards compatible with SDP, as well as the current proliferation of SDP
in several protocols, we need to come up with at least a minimal solution
for SDP (and fairly soon too).

The abstract follows:

   This document proposes a set of Session Description Protocol (SDP)
   attributes that allow SDP to provide a minimal and backwards
   compatible capability negotiation mechanism. The mechanism is
   intended as a simple and limited solution to the general capability
   negotiation problem being addressed by ongoing work on the next
   generation of SDP, also known as SDPng.

Regards

        Flemming

--
Flemming Andreasen
Cisco Systems

---

From: Thomas LEVY <[email-masked]>
Date: Fri, 24 Nov 2000 15:40:44 +0100

Hello Flemming,

The ideas of the draft seems interesting to me.
Furthermore, it seems very close to some discussion we have within
Megaco mailing list concerning media gateway capabilities exchange.
My question will be the following:
What do you exactly mean by providing a capability descriptions at the
media level?
On my opinion, media capabilities apply to whole the endpoint but not to
a particular media stream.
Do you imagine several streams with the same media type having different
capabilities?

Regards Thomas,

Flemming Andreasen wrote:

> The premise of this draft is that we have a pressing need for a
> capability negotiation mechanism. While work on SDPng has begun, it is
> still at a somewhat early stage, and given that SDPng is anticipated
> to not be backwards compatible with SDP, as well as the current
> proliferation of SDP in several protocols, we need to come up with at
> least a minimal solution for SDP (and fairly soon too).
>
>
> The abstract follows:
>

---

From: Flemming Andreasen <[email-masked]>
Date: Fri, 24 Nov 2000 18:01:17 +0100

Hi Thomas

Multimedia would be one example of having different capabilities
associated with different media streams. The ever popular DTMF
discussion would be another, in as much as you might want to limit
capabilities for a DTMF media stream to just that.

-- Flemming

Thomas LEVY wrote:

> On my opinion, media capabilities apply to whole the endpoint but not
> to a particular media stream.
> Do you imagine several streams with the same media type having
> different capabilities?
>
> Regards Thomas,
>
>> capability negotiation mechanism. While work on SDPng has begun, it
>> is still at a somewhat early stage, and given that SDPng is
>> anticipated to not be backwards compatible with SDP, as well as the
>> current proliferation of SDP in several protocols, we need to come
>> up with at least a minimal solution for SDP (and fairly soon too).
>>
>>
>> The abstract follows:
>>
--
Flemming Andreasen
Cisco Systems

---

From: Thomas LEVY <[email-masked]>
Date: Thu, 30 Nov 2000 13:49:00 +0100

Hi Flemming,

I am not sure to understand the example you are referring to:
1) Is it that the system is not able to handle some kind of audio (for
inst:PCMU) and DTMF simultaneously?
or
2) Is it that the system is able to but doesn't want to associate some
kind of audio (for inst:PCMU) and DTMF for this particular stream?
or an other case?

Thomas,

Flemming Andreasen wrote:

>> What do you exactly mean by providing a capability descriptions at
>> the media level?
>> On my opinion, media capabilities apply to whole the endpoint but
>> not to a particular media stream.

---

From: Flemming Andreasen <[email-masked]>
Date: Thu, 30 Nov 2000 12:42:20 -0500

> kind of audio (for inst:PCMU) and DTMF for this particular stream?

It's the second case. Consider an application that wants to receive DTMF
input from the user. Different mechanisms have been proposed for this,
and one of these is the use of an RFC 2833 DTMF media stream. In the
case where DTMF is all you wanted to support for a media stream while
having another media stream at the same time, you want a way to express
that a given capability only applies to a given media stream.

-- Flemming

--
Flemming Andreasen
Cisco Systems