Subject: RE: [MMUSIC] RTSP and mobility

From: "Enrico Balatti" <[email-masked]>
Date: Fri, 22 Aug 2003 08:46:34 +0200

Hi Magnus, Tom, Henning and Ashutosh,

I agree with you about some "Application Mobility" paragraphs 
in the RTSP core specification and I also agree on the change 
from MAY to MUST in section 10.4.

According to other commitments, I'll try to look through the specification 
searching any more conflicts or limitations.

Best Regards,
Enrico

-----Original Message-----
From: Magnus Westerlund [mailto:[email-masked]]
Sent: mercoledì 20 agosto 2003 9.36
To: Tom Marshall
Cc: Henning Schulzrinne; Enrico Balatti; [email-masked]
Subject: Re: [MMUSIC] RTSP and mobility

Hi Tom,

Yes, you are correct that the current MAY would need to be changed to 
MUST to always allow it. Performing this change may be a bit to much 
change. I think that it would be better to explain why support of this 
functionality is good, based on that it makes Application layer mobility 
possible. If there is need to learn the support for this, we should 
define a feature tag for it.

Is anybody willing to look through the specification to see if there are 
any more conflicts or limitations and provide a draft informational text 
about this?

Best Regards

Magnus

Tom Marshall wrote:

> In order to make this work, don't you also need to s/MAY/MUST/ in the
> first
> paragraph of 10.4?  This would seem to be a controversial change.
> 

Magnus Westerlund

Multimedia Technologies, Ericsson Research EAB/TVA/A
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From: Magnus Westerlund <[email-masked]>
Date: Fri, 22 Aug 2003 09:06:01 +0200

Hi Enrico,

> from MAY to MUST in section 10.4.

Please not jump ahead of things. Any change of this MAY to a MUST is in 
need of more extended discussion and consideration. I think I am against 
  changing this due to backwards compatibility reasons. If we would 
change it and a updated client assumes that all server support this 
functionality, while all ones does not, it will create problems. In my 
opinion the most reasonable solution of this problem is to clearly 
motivate why you should implement this functionality. This can be done 
in a satisfactory way by creating a application mobility section. To 
ensure that a client can determine the servers support of the mobility 
features a feature tag to use in supported header can be defined. That 
way the client can determine if it will work before attempting it.

> searching any more conflicts or limitations.

Very Good!

Cheers

Magnus Westerlund