Subject: RE: [Simple] Adding a telephone number to a basic PIDF document

From: "Tim Rang" <[email-masked]>
Date: Fri, 7 Oct 2005 13:22:50 -0700

1 question inline-

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] On
Behalf
> Of Jonathan Rosenberg
> Sent: Thursday, October 06, 2005 9:14 PM
> To: Tim Rang
> Cc: Paul Kyzivat; Simple WG
> Subject: Re: [Simple] Adding a telephone number to a basic PIDF
document
> 
> Firstly, I agree with Paul, that if you want to have a way to tell a
> watcher, "here is a phone number to call me on the telephone", this is
> represented by a service in the data model, whose contact is a tel
URI.
> 
> More below.
> 
> Tim Rang wrote:
> > Thanks Paul.  Would it be fair to say that devices are generally
only
> > used when multiple services need to be represented together?
> 
> Devices serve many roles, one of which is as a correlator for
services.
> They also serve to convey attributes which are, in fact, attributes of
a
> physical device - geo-location, for example.
> 
> >
> > Back to your question regarding the missing contact element, it
looks
> > like I have something else I need to clear up.  The schema in RFC
> > 3863 makes contact an optional element for tuple.  I figured that if
> > the contact is omitted, then it should be simply derived from either
> > the subscription request URI, or the entity attribute.  If that is
> > not the case, and the contact element really is optional, then what
> > does it mean to have a tuple with no contact?
> 
> No. If contact is not present, it means that the presentity wishes to
> indicate that the service is available, but a contact for reaching it
is
> not being provided.

[Tim Rang] What is the value of allowing that?  If a presence document's
purpose is to convey ability and willingness to communicate, then what
am I saying by showing a watcher a service which is effectively blocked
from that watcher by the omission of the contact?  If I don't want a
watcher to contact me at a service, I would just not let them see it at
all.  

Is there a practical application for this and if not, why not require
the contact element always be present for services?  

Thanks,
Tim

> 
> -Jonathan R.
> --
> Jonathan D. Rosenberg, Ph.D.                   600 Lanidex Plaza
> Director, Service Provider VoIP Architecture   Parsippany, NJ
07054-2711
> Cisco Systems
> [email-masked]                              FAX:   (973) 952-5050
> http://www.jdrosen.net                         PHONE: (973) 952-5000
> http://www.cisco.com
> 
> _______________________________________________
> Simple mailing list
> [email-masked]
> https://www1.ietf.org/mailman/listinfo/simple

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

---

From: Paul Kyzivat <[email-masked]>
Date: Fri, 07 Oct 2005 17:11:41 -0400

Tim Rang wrote:

>>is not being provided.

Well, if you want to build a system that does this, that is fine. Nobody 
is saying you MUST create tuples with no contact.

I see value in describing the capabilies of a service that is not 
currently available. At least then a watcher might decide to check back 
later.

	Paul

---

From: Jonathan Rosenberg <[email-masked]>
Date: Fri, 07 Oct 2005 21:13:56 -0400

inline.

> watcher to contact me at a service, I would just not let them see it at

I can imagine applications where I'd like to tell someone I'm on the 
phone, or have IM, but not necessarily give them the opportunity to 
contact me.

> the contact element always be present for services?  

PIDF made it optional, and this was debated extensively during the 
development of PIDF as I recall (then again, most everything there was 
debated extensively....). Anyway, the current data model says nothing at 
all about omitting contact, and it should. I'll put some text in for 
that in the next revision.

Thanks,
Jonathan R.

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