Re: [siprec] Can an MS object span several CSs in a CSG?

["Parthasarathi R (partr)" <[e-mail]>]

John,

===================================================================
> 3) B transfer the call of A & B to C using REFER, B2BUA converts REFER

> to RE-INVITE towards A & C and A & C are connected. B2BUA updates RS 
> with CS2, Participant1 as A & participant2 as C, MS1(A's media 
> stream), MS2(C's media stream). There is no update on RS1, CSG1, MS1, 
> MS2. MS2 will become MS2 with the new association and in terms of 
> format, it will associate with <send> tag
[JRE] What harm is done (what do we lose) if, following transfer, A's
media stream is called MS3 and C's media stream is called MS4? 
=====================================================================
<Partha> To indicate MS1 as MS3, MS1 media block has to be stopped in
the partial-update and start MS3 separate which is not required in case
there is a means to have common MS1. </Partha>

========================================================================
=======================
MS3 can reference the same SDP m-line (through a=label) as MS1, and
likewise MS4 could reference the same SDP m-line as MS2, if we are
concerned about recycling media descriptions in RS SDP.
========================================================================
==================
<Partha> As you mentioned, we will lose recycling of media description
in RS SDP without common value in media stream object for this scenario.
AFAIK, Your proposal needs enhancement in RFC 4574 as label attribute
scope is within single SIP message and not required to be unique in all
SIP messages of a given dialog. </Partha> 

Thanks
Partha

John (as individual)

> 
> Thanks
> Partha  
> 
> -----Original Message-----
> From: Charles Eckel (eckelcu) 
> Sent: Wednesday, May 25, 2011 1:39 AM
> To: Ram Mohan R (rmohanr); Parthasarathi R (partr); 'Elwell, John';
> '[e-mail]'
> Subject: RE: [siprec] Can an MS object span several CSs in a CSG?
> 
> Hi Ram,
> 
> I think that is many cases, they will be treated as separate 
> MSs due to
> the complexities you mention. However, I am trying to understand if
> Partha feels allowing an SRC to treat them as a single MS is still
> required. If not, then what is a use case? A concrete example 
> would help
> me, and potentially others, to better understand the motivation behind
> Partha's requirement for modeling media from multiple CSs as a single
> MS.
> 
> Cheers,
> Charles
> 
> > -----Original Message-----
> > From: Ram Mohan R (rmohanr)
> > Sent: Tuesday, May 24, 2011 9:36 AM
> > To: Charles Eckel (eckelcu); Parthasarathi R (partr); Elwell, John; 
> > [e-mail]
> > Subject: RE: [siprec] Can an MS object span several CSs in a CSG?
> > 
> > Charles,
> > 
> > I did bring about this specific usecase of MMOH/MOH stream being 
> > played to different participants earlier and suggested that 
> they have 
> > to treated as a same MS across multiple CSs (potentially recorded
> using multiple RSs).
> > Refer 
> > http://www.ietf.org/mail-archive/web/siprec/current/msg01886.html
> > 
> > We had several discussions on it and it and several folks were in 
> > favor of treating it as separate MS as there would be 
> complexity in DB
> design.
> > 
> > Regards,
> > Ram
> > 
> > 
> > > -----Original Message-----
> > > From: [e-mail] [mailto:[e-mail]] On 
> > > Behalf Of Charles Eckel (eckelcu)
> > > Sent: Tuesday, May 24, 2011 9:11 PM
> > > To: Parthasarathi R (partr); Elwell, John; [e-mail]
> > > Subject: Re: [siprec] Can an MS object span several CSs in a CSG?
> > >
> > > Hi Partha,
> > >
> > > Is an example of this the same music on hold audio stream 
> existing 
> > > as the same MS within multiple CSs? If so, then I understand your 
> > > requirement to be that the SRC be able to indicate multiple 
> > > instances of this audio stream within several CSs as 
> being the same 
> > > MS. Is that correct?
> > >
> > > Thanks,
> > > Charles
> > >
> > > > -----Original Message-----
> > > > From: [e-mail] 
> [mailto:[e-mail]] On
> > > Behalf Of Parthasarathi R (partr)
> > > > Sent: Tuesday, May 24, 2011 4:26 AM
> > > > To: Elwell, John; [e-mail]
> > > > Subject: Re: [siprec] Can an MS object span several CSs 
> in a CSG?
> > > >
> > > > John,
> > > >
> > > > I agree that it is not mandatory to consider recorded 
> stream of a 
> > > > specific participant in several CS within the same CSG as one
> > > recorded
> > > > stream but SIPREC protocol design MUST NOT restrict a 
> SRC in case 
> > > > it wishes to design in such a way.
> > > >
> > > > Thanks
> > > > Partha
> > > >
> > > > -----Original Message-----
> > > > From: [e-mail] 
> [mailto:[e-mail]] On
> > > Behalf
> > > > Of Elwell, John
> > > > Sent: Tuesday, May 24, 2011 1:06 PM
> > > > To: [e-mail]
> > > > Subject: [siprec] Can an MS object span several CSs in a CSG?
> > > >
> > > > We seem to have consensus that a Media Stream object 
> represents a 
> > > > recorded media stream, contributed to by one, several or all 
> > > > Participants. However, Partha also wrote:
> > > >
> > > > "2) Each MS lifetime related to CSG because participant 
> may move 
> > > > from one CS to another CS within single CSG and also 
> CSG will span
> 
> > > > across multiple RS."
> > > >
> > > > I am not sure we had resolved this during earlier 
> discussions on 
> > > > the scope of an MS object. Although the same Participant can 
> > > > participate
> > > in
> > > > several CSs within the same CSG, I don't think the 
> recorded media 
> > > > streams need to be considered the same. Any other views?
> > > >
> > > > John (as individual)
> > > > _______________________________________________
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> > > > [e-mail]
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