Subject: [Simple] sip, sips, pres schemas

From: Avshalom Houri <[email-masked]>
Date: Thu, 5 Oct 2006 11:42:14 +0200

This question may have been raised before but I do not recall that it
was completely answered.

Assume that a user:
* Subscribes to sips:[email-masked]
* Subscribes to sip:[email-masked]
* Subscribes to pres:[email-masked]

This may happen especially when subscribing to groups.

Should these be considered as three separate entities?
Should each subscription get a notification only when the subscribed to
schema is published?

If the user should get the same PIDF document for all its subscriptions
(no matter which scheme the user have used), what should be the leading
entity sips, sip, pres? Should the leading entity be changed as the
presence server learns more general schemas (pres: is more general
then sip: for example)? I am not sure how clients will handle changing
the leading entity on different notifies.

--Avshalom

_______________________________________________
Simple mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/simple

---

From: Jonathan Rosenberg <[email-masked]>
Date: Thu, 05 Oct 2006 17:05:56 -0400

inline.

> Should these be considered as three separate entities?

The sip and sips would be the same entity. The pres ought to be.

> Should each subscription get a notification only when the subscribed to

Assuming each URI points to the same resource, there would be a notify 
on each subscription when it changes, whether its a consequence of a 
publish or something else.

> entity sips, sip, pres?

Well, this at least is answered in RFC 4479, which says this:

   When a document is constructed, the presentity URI is ideally set to
    the identifier used to request the document in the first place.  For
    example, if a document was requested through a SIP SUBSCRIBE request,
    the presentity URI would match the Request URI of the SUBSCRIBE
    request.  This follows the principle of least surprise, since the
    entity requesting the document may not be aware of the other
    identifiers for the presentity.

  >Should the leading entity be changed as the

I don't follow here. What do you mean by 'learn'? The subscription is 
established to a particular URI, and the notifications would contain a 
presentity ID of that form.

-Jonathan R.

-- 
Jonathan D. Rosenberg, Ph.D.                   600 Lanidex Plaza
Cisco Fellow                                   Parsippany, NJ 07054-2711
Cisco Systems
[email-masked]                              FAX:   (973) 952-5050
http://www.jdrosen.net                         PHONE: (973) 952-5000
http://www.cisco.com

---

From: Avshalom Houri <[email-masked]>
Date: Fri, 6 Oct 2006 16:46:02 +0200

inline

--Avshalom

> publish or something else.
According to the text from 4479 we need to create a different presentity 
URI for
each subscription where the presentity URI is the subscribed to URI.
>     identifiers for the presentity.
So for example, consider a public group for example, it has 2 entries of
Joe. One with SIPS, one with SIP, according to the text above, the pres 
doc
for SIPS entry in the group should have a presentity URI of SIPS and
the other should have a presentity URI of SIP.
> presentity ID of that form.
According to the text above from 4479 there will be only a single 
presentity
URI all the time which will be the subscribed to URI so this question is 
answered
by 4479.