Subject: [Geopriv] HELD 'expires' parameter

From: "Stark, Barbara" <[email-masked]>
Date: Tue, 9 Oct 2007 08:07:54 -0400

Right now, expires is defined only for use with a returned location
reference. I was wondering if there might be value in also allowing it
to be returned with a value. The meaning would be that the device needs
to do another query to update its location, before 'expires'. 

In phonebcp-02, there's a recommendation that devices which don't expect
to roam should refresh location daily, and those that can be expected to
roam should refresh more frequently. The problem is that many devices
don't know that they're part of a roaming network. But the access
network often does know. So, if we use 'expires' with  location values,
the access network could let the device know that more frequent
refreshes are appropriate.

Just a thought.
Barbara

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From: Richard Barnes <[email-masked]>
Date: Tue, 09 Oct 2007 09:11:08 -0400

That seems reasonable, but it might overlap/conflict with the 
"retention-expires" rule in the returned PIDF-LO.  Slightly different 
semantics, but I think the effect is the same.

--Richard

---

From: "Stark, Barbara" <[email-masked]>
Date: Tue, 9 Oct 2007 09:38:53 -0400

Thanks. I'd overlooked that parameter in the PIDF-LO. You're right --
that PIDF-LO parameter can meet this need.
Barbara 

-----Original Message-----
From: Richard Barnes [mailto:[email-masked]] 
Sent: Tuesday, October 09, 2007 9:11 AM
To: Stark, Barbara
Cc: [email-masked]
Subject: Re: [Geopriv] HELD 'expires' parameter

--Richard

Stark, Barbara wrote:
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If you received this in error, please contact the sender and delete the
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From: "Winterbottom, James" <[email-masked]>
Date: Tue, 9 Oct 2007 16:51:24 -0500

This isn't really the aim of retention-expires parameter.
retention-expires indicates the point in time after which a recipient is
no longer permitted to hold the location object, it does not provide any
indicator as to whether the Target is still at the location or not. I
don't think that over-loading its value to indicate that the Target
should re-acquire its location is a good idea.

I think we either need a separate indicator in the PIDF-LO, or a
parameter in the HELD locationResponse message.

Cheers
James 

> From: Stark, Barbara [mailto:[email-masked]]
> Sent: Tuesday, 9 October 2007 11:39 PM
> To: Richard Barnes
> Cc: [email-masked]
> Subject: RE: [Geopriv] HELD 'expires' parameter
> 
> > to roam should refresh location daily, and those that can be
expected
> to
to
> which it is addressed and may contain confidential, proprietary,
and/or
> privileged material. Any review, retransmission, dissemination or
other
> use of, or taking of any action in reliance upon this information by
> persons or entities other than the intended recipient is prohibited.
If
> you received this in error, please contact the sender and delete the
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> 
> 
> 
> 

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From: Matt Lepinski <[email-masked]>
Date: Wed, 10 Oct 2007 10:25:53 -0400

James,

I agree that the retention-expires parameter doesn't really have the 
semantics that Barbara indicated.

However, what is not clear to me is how the access network knows at the 
time of the HELD request, how long the returned location is valid. In 
many scenarios this would depend on how much the device is going to be 
moving, and I don't see device movement as being very predictable by the 
access network.

This is a general issue with location-by-value. In many scenarios 
neither the device nor the access network is in a position to predict 
how long a location returned by HELD will be valid.

- Matt Lepinski :->

Winterbottom, James wrote:

>>>reference. I was wondering if there might be value in also allowing
>>>      
>>>
>it
>  
>
>>>to be returned with a value. The meaning would be that the device
>>>      
>>>
>>needs
>>    
>>
>>>In phonebcp-02, there's a recommendation that devices which don't
>>>      
>>>
>>expect
>>    
>>
>>>roam should refresh more frequently. The problem is that many
>>>      
>>>
>devices
>  
>
>>>network often does know. So, if we use 'expires' with  location
>>>      
>>>
>>values,
>>    
>>
>>>The information transmitted is intended only for the person or
>>>      
>>>
>entity
>  
>
>>and/or privileged material. Any review, retransmission, dissemination
>>    
>>
>or
>  
>
>>other use of, or taking of any action in reliance upon this
>>    
>>
>information
>  
>
>>by persons or entities other than the intended recipient is
>>    
>>
>prohibited.
>  
>
>>If you received this in error, please contact the sender and delete
>>    
>>
>the
>  
>

---

From: "Dawson, Martin" <[email-masked]>
Date: Wed, 10 Oct 2007 09:53:16 -0500

I tend to agree Matt. Certainly the location in a mobile network is
really only valid instantaneously - so the application needs to judge
whether the value is too old to be trusted. And even for a fixed network
attachment, the network can't anticipate whether or not the device is
going to immediately detach and move a considerable distance as soon as
the location is provided.

I think the goal is really to give the recipient of the location
information - and this could be the device itself - an indication of the
nature of the point of attachment. Contrasting a residential DSL
connection with a mobile WiMAX connection, the location associated with
the former effectively never changes while for the latter it can change
moment to moment. It's useful for the application to know this as it
provides anecdotal information that is useful in deciding when or
whether to request an update to location - amongst other things.

I do wonder whether a nature-of-network indicator which simply said
"fixed" or "mobile" would not be sufficient.

Cheers,
Martin

-----Original Message-----
From: Matt Lepinski [mailto:[email-masked]] 
Sent: Thursday, 11 October 2007 12:26 AM
To: Winterbottom, James
Cc: [email-masked]
Subject: Re: [Geopriv] HELD 'expires' parameter

James,

access network.

- Matt Lepinski :->

---

From: "Stark, Barbara" <[email-masked]>
Date: Wed, 10 Oct 2007 11:52:05 -0400

The access network knows whether the access network technology is fixed
(twisted pair, coax, fiber) or not (like WiMAX or metro mesh Wi-Fi). For
fixed, the 24 hour default is perfectly reasonable. For RF, it may not
be, because devices may move around. The end device may be behind a
bridge device or router that connects to the access network, in which
case it wouldn't know the nature of the access network.

Right now, phonebcp suggests 24 hours, unless the device has reason to
believe it may be mobile. If the device doesn't know the nature of the
access network, then it will probably just use 24 hours.
Barbara

-----Original Message-----
From: Matt Lepinski [mailto:[email-masked]] 
Sent: Wednesday, October 10, 2007 10:26 AM
To: Winterbottom, James
Cc: Stark, Barbara; Richard Barnes; [email-masked]
Subject: Re: [Geopriv] HELD 'expires' parameter

James,

access network.

- Matt Lepinski :->

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The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential, proprietary, and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from all computers. GA625