Subject: [siprec] Question on start-time

From: "Elwell, John" <[email-masked]>
Date: Tue, 30 Aug 2011 10:18:35 +0200

The start-time child element is optional in elements like participant, session, etc.. If it is included in one version of the metadata and then omitted in the next version, what does this mean? Once added, does it need to be included in each iteration of the metadata until that element has been deleted (stop-time added), or can it be omitted? What assumption should the SRS make in this case? Should it assume the value is unchanged?

John (as individual)

John Elwell
Tel: +44 1908 817801 (office and mobile)
Email: [email-masked]
http://www.siemens-enterprise.com/uk/

Siemens Enterprise Communications Limited.
Registered office: Brickhill Street, Willen Lake, Milton Keynes, MK15 0DJ.
Registered No: 5903714, England.

Siemens Enterprise Communications Limited is a Trademark Licensee of Siemens AG.

---

From: "Ram Mohan R (rmohanr)" <[email-masked]>
Date: Tue, 30 Aug 2011 15:02:46 +0530

Hi John,

Please see inline

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] On
> Behalf Of Elwell, John
> Sent: Tuesday, August 30, 2011 1:49 PM
> To: [email-masked]
> Subject: [siprec] Question on start-time
> 
> The start-time child element is optional in elements like participant,
> session, etc.. If it is included in one version of the metadata and
> then omitted in the next version, what does this mean? Once added,
does
> it need to be included in each iteration of the metadata until that
> element has been deleted (stop-time added), or can it be omitted? What
> assumption should the SRS make in this case? Should it assume the
value
> is unchanged?

Start(associate-time) is the time at which an element is
associated/started. For e.g, in case of a participant associate-time is
the time at which a participant associates to a session. Dis-associate
time is the time a participant disassociates from a session. Note that
the participant may again associate to the same CS during its lifetime
as we agreed in IETF81.

For the above an SRC may send a snapshot metadata having associate-time
for participant at Instance T0. Subsequent metadata snapshots(partial
updates) from SRC to SRS ( say sent at time T1, T2) does not have the
associate-time for the participant. 
Meanwhile if the SRS requests for a complete snapshot at some point (
say T3) from SRC, that snapshot from SRC may include the associate-time
in case the SRC has saved it.
Eventually when the participant disassociates( at time T4) from the CS
metadata snapshot from SRC to SRS will have a disassociate-time.

So to summarize the associate-time need not be included every time.
Also there may be implementations where an SRC may not send times at all
(as they are optional). 

Regards,
Ram

> _______________________________________________
> siprec mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/siprec

---

From: "Elwell, John" <[email-masked]>
Date: Tue, 30 Aug 2011 14:09:57 +0200

If this is a common understanding, perhaps we need some general statement in the draft on how to interpret missing child elements of elements (e.g., start-time) that are free-standing (i.e., participant, group, session, stream).

John 

> From: Ram Mohan R (rmohanr) [mailto:[email-masked]] 
> Sent: 30 August 2011 10:33
> To: Elwell, John; [email-masked]
> Subject: RE: [siprec] Question on start-time
> 
> Hi John,
> 
> Please see inline
> 
> > Registered office: Brickhill Street, Willen Lake, Milton 
> Keynes, MK15
> > 0DJ.

---

From: "Ram Mohan R (rmohanr)" <[email-masked]>
Date: Tue, 30 Aug 2011 18:55:45 +0530

Sure. I will try to add some text in the draft to make it explicit. Do
we want the text to be added in ver 04 itself ? or Do we need more
discussions ?

While I was thinking of start/stop (or associate/disassociate) for
different elements I have a question regarding times for session time. I
will start a new thread for the same.

Regards,
Ram

> From: Elwell, John [mailto:[email-masked]]
> Sent: Tuesday, August 30, 2011 5:40 PM
> To: Ram Mohan R (rmohanr); [email-masked]
> If this is a common understanding, perhaps we need some general
> statement in the draft on how to interpret missing child elements of
> elements (e.g., start-time) that are free-standing (i.e., participant,
> group, session, stream).
> 
> John
> 
> > > Siemens Enterprise Communications Limited is a Trademark Licensee
> of
> > > Siemens AG.