Subject: [MMUSIC] RE: Comments on draft-einarsson-mmusic-rtsp-macuri-00.txt

From: Torbjörn Einarsson (KI/EAB)<[email-masked]>
Date: Tue, 5 Sep 2006 13:40:10 +0200

Hi Hari,

It should be quite straightforward to inroduce an extra header instead of modifying the Aggregated Control URI in the PLAY request.

Our proposal for choosing one channel and then another using different AC URIs looks like (dropping all headers):

Alternative URIs defined in SDP:
a=altcontrol:rtsp://server/channel1
a=altcontrol:rtsp://server/channel2

Then the setup and viewing of ch1, followed by ch2, would be:

SETUP rtsp://server/commonuri/track1 RTSP/2.0

SETUP rtsp://server/commonuri/track2 RTSP/2.0

PLAY rtsp://server/channel1 RTSP/2.0

PLAY rtsp://server/channel2 RTSP/2.0

One possible alternative using headers and keeping the common AC URI would be to have a new header called Alt-Control and then put the channel specific identifier (e.g. AC URI) there:

SETUP rtsp://server/commonuri/track1 RTSP/2.0

SETUP rtsp://server/commonuri/track2 RTSP/2.0

PLAY rtsp://server/commonuri RTSP/2.0
Alt-Control: rtsp://server/channel1

PLAY rtsp://server/commonuri RTSP/2.0
Alt-Control: rtsp://server/channel2

However, we think the first choice using a specific AC URIs in the PLAY request is cleaner.

Regarding the full hybrid multicast/unicast use cases, they will probably be rather system specific. We will probably work out a detailed description and suggest to 3GPP SA4. Maybe one can extract something from such a work and send it out here, but at the moment, we don't have anything ready to distribute.

Regards,
Torbjörn

-----Original Message-----
From: Desineni, Harikishan [mailto:[email-masked]] 
Sent: den 30 augusti 2006 20:52
To: Torbjörn Einarsson (KI/EAB)
Cc: [email-masked]
Subject: Comments on draft-einarsson-mmusic-rtsp-macuri-00.txt

The first option (new header) is not clear to me. I would like see a comparison between two options along with detailed signaling examples including all proposed SDP attributes. Few detailed examples on how a hybrid RTSP client switches from unicast to BCAST and BCAST to unicast would really help understand the proposal in this draft. May be we can start discussing complete examples in this thread.

4.2.  Channel selection signalling

"To distinguish different channels, one can either introduce a new header or use
   different aggregated control URIs for each channel.  Among these two,
   we propose to use multiple aggregated control URIs (AC URIs) since
   URIs have a well-defined syntax and it is easy to extend SDP or other
   session descriptions to include multiple URIs."

Thanks,
Hari

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