Subject: [Geopriv] Location URI \Types

From: Hannes Tschofenig <[email-masked]>
Date: Sat, 08 Mar 2008 05:14:11 +0200

Here is the suggested terminology for Location URIs 
(somewhat simplified after a couple of attempts to get the text readable). 

   Static location URIs:

      Whenever a static location URI is de-referenced, the same static
      location is returned.  These URIs are typically constrained by a
      start and a stop time.  For example, the location of Alice on a
      her 21st birthday at 10:00 AM is a static location URI, because
      she was in a place at that time and date, so, the location does
      not change.  The path that Alice took on the same day from 12 PM
      to 2 PM is also a static location URI, because as a result of its
      de-reference the location recipient will get the same collection
      of locations.

   Dynamic location URIs:

      Every time a dynamic location URI is de-referenced a new
      (potentially different) location is provided.  Typically these
      URIs do not have a constraint with the time.  Assume Alice
      acquires a URI that points to her current location, every time
      that a location recipient invokes the URI, he will get a different
      location (assuming that Alice's location changes).  Another
      example can be when Alice acquires a URI that provides her
      location between today noon and now, so, when the location
      recipient invokes the URI, he will be accumulating further
      locations, providing that Alice is changing her location.

   Dynamic location URIs have stronger privacy considerations, because
   the target does not really know what is the location supplied at any
   time.  However, the target has mechanisms to constraint the
   availability of a dynamic location URI, for example, by imposing a
   time when the reference expires.

Based on 
http://www.ietf.org/internet-drafts/draft-garcia-simple-indirect-presence-publish-00.txt

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From: "James M. Polk" <[email-masked]>
Date: Sat, 08 Mar 2008 19:01:59 -0600

Hannes

What is this for?

I do not agree these definitions are necessary.  It's analogous to an 
IP phone, which is either static or mobile.  We've decided long ago 
to consider everything in IP as mobile, therefore, the URI is the 
same, it's the answer that may return a specific timestamp that 
indicates where Alice was a a certain time and day, but her URI 
doesn't change, therefore the definition or distinction is unnecessary IMO.

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From: Hannes Tschofenig <[email-masked]>
Date: Sun, 09 Mar 2008 20:18:21 +0200

A terminology for the types of URI, as discussed during the last IETF 
meeting, allows us to understand the properties much better.
It, for example, allows us to argue what works in the DHCP case and what 
does not.

It is also important for the way how GEOPRIV works in the concert with 
other applications, see
http://www.ietf.org/internet-drafts/draft-garcia-simple-indirect-presence-publish-00.txt

See Henning's presentation:
http://www.cs.columbia.edu/~hgs/papers/2007/IETF70-geopriv-ref.ppt

I got the impression that people found Hennings proposal very important.

Ciao
Hannes

James M. Polk wrote:
> IP phone, which is either static or mobile.  We've decided long ago to 
> consider everything in IP as mobile, therefore, the URI is the same, 
> it's the answer that may return a specific timestamp that indicates 
> where Alice was a a certain time and day, but her URI doesn't change, 
> therefore the definition or distinction is unnecessary IMO.
>

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From: "James M. Polk" <[email-masked]>
Date: Sun, 09 Mar 2008 14:59:23 -0500

While I agreed Henning's preso was good, I don't remember there being 
a distinction needed to be made between identifying whether a device 
is non-mobile vs. mobile - as I maintain our old position that's 
still valid that anything IP based is to be considered mobile 
(therefore dynamic under your definition).... but I might not be 
remembering some aspect of the preso at this point.

One way I'm looking at the differences in what is written below is 
the example given in the dynamic definition in which a URI is for 
Alice's device, but only from today until tomorrow. I maintain that 
is still a mobile device, but can have the same URI if Alice doesn't 
move to another SP or domain.  Hence my confusion in the text given.

James

At 01:18 PM 3/9/2008, Hannes Tschofenig wrote:
>A terminology for the types of URI, as discussed during the last 
>IETF meeting, allows us to understand the properties much better.
>It, for example, allows us to argue what works in the DHCP case and 
>what does not.
>
>It is also important for the way how GEOPRIV works in the concert 
>with other applications, see
>>I do not agree these definitions are necessary.  It's analogous to 
>>an IP phone, which is either static or mobile.  We've decided long 
>>ago to consider everything in IP as mobile, therefore, the URI is 
>>the same, it's the answer that may return a specific timestamp that