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

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

John,

The callflow mentioned by me is the basic primitive in the call center
scenario wherein customer (participant) is same throughout the session
and agents are changed using transfer service and B2BUA acts as SRC.
IMO, it is one of key requirement to be considered in case we support
for partial-update. This may not be the only callflow where MS
partial-update is required in this fashion. During -00 format draft, I
thought that the partial-update is not required but lot of folks raised
the concern that partial update is important. Current, -01 format draft
is designed to support partial-update. Now, You propose to restrict MS
partial-update across CS. IMO, it is a not good idea to restrict in the
protocol level. Anyway, I think that we need others opinion before
conclude here.

Enhancing label attribute across the multiple SIP message to tie between
Metadata XML and RS SDP m-line is possible. SRC has to ensure that label
for the given RS SDP m-line should have same label throughout single CSG
even though it span across multiple CS and multiple RS. Even then, it
will not meet partial-update requirement as mentioned below in this mail
thread. At this moment, I'm favoring URN UUID and not label attribute
enhancement.   

Please read inline

Thanks
Partha

-----Original Message-----
From: Elwell, John [mailto:[e-mail]] 
Sent: Wednesday, May 25, 2011 7:17 PM
To: Parthasarathi R (partr); Charles Eckel (eckelcu); Ram Mohan R
(rmohanr); [e-mail]
Subject: RE: [siprec] Can an MS object span several CSs in a CSG?

 

> -----Original Message-----
> From: Parthasarathi R (partr) [mailto:[e-mail]]
> Sent: 25 May 2011 08:48
> To: Elwell, John; Charles Eckel (eckelcu); Ram Mohan R (rmohanr); 
> [e-mail]
> Subject: RE: [siprec] Can an MS object span several CSs in a CSG?
> 
> 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>
[JRE] It seems this distorts the model in order to give some minor
efficiency improvement during metadata updates. I doubt that this alone
is sufficient justification for having the MS persist from one CS to
another CS.

> 
> ==============================================================
> ==========
> =======================
> 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.
[JRE] I don't understand your point. With my proposal we can still
recycle RS SDP m-lines.

<Partha> Agreed that Recycle is possible with your proposal. I indicated
the need for unique-id in this  requirement </Partha>

> 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> 
[JRE] But I think we could nail that down as a requirement of the SIPREC
protocol.

John (as individual)

> 
> 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)
> > > > > _______________________________________________
> > > > > siprec mailing list
> > > > > [e-mail]
> > > > > https://www.ietf.org/mailman/listinfo/siprec
> > > > > _______________________________________________
> > > > > siprec mailing list
> > > > > [e-mail]
> > > > > https://www.ietf.org/mailman/listinfo/siprec
> > > > _______________________________________________
> > > > siprec mailing list
> > > > [e-mail]
> > > > https://www.ietf.org/mailman/listinfo/siprec
> > 
>