Subject: [Geopriv] What location does a PIDF-LO refer to?

From: Hannes Tschofenig <[email-masked]>
Date: Mon, 24 Sep 2007 15:39:36 +0200

Hi all,

Karl Heinz raised an interesting issue.

So, here is what he wrote:

"
LLDP-MED has a "what" element, describing if the location of the client 
itself, of the DHCP server or of the network element closest to the 
client is provided. This seems to be useful information, but where to 
put this in a PIDF document?
"

Furthermore, in a discussion with Henning and James about the update of 
the PIDF-LO profile draft (aiming to reflect the feedback regarding the 
usage of RFC 4479) we came across two questions:
 (a) How do we indicate to what the location information refers to?
 (b) Where is the right place to put location information within a PIDF-LO?

Regarding the later aspect we learned that location information should 
be placed into the <device> element when a LIS creates it (rather than 
using <tuple> or <person>).

The <device> element has a mandatory element, the <deviceID>, that has 
to contain a URN. Now, what information should we put in there? IP 
address, MAC address, anything else?

What URN scheme should we use?

For (a) we indicated that the 'entity' attribute inside the <presence> 
element, see Section 4.1.1 of RFC 3863, contains the entity to which the 
location refers to.

So, how would we set these fields when the Target receives location 
information using LLDP-MED?

Ciao
Hannes

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---

From: "Karl Heinz Wolf" <[email-masked]>
Date: Mon, 24 Sep 2007 15:57:12 +0200

> address, MAC address, anything else?

just one note: when LLDP-MED "what" reports "location of the network
element believed closest to the client" no IP address of that network
element is available anyway.

---

From: Hannes Tschofenig <[email-masked]>
Date: Mon, 24 Sep 2007 16:00:41 +0200

Hi

> element is available anyway.

For LLDP-MED that's true. But when a LIS creates a PIDF-LO then there is 
the question whether the MAC address or another identifier would be put 
in there since there are more choices in the general case.

ciao
Hannes

---

From: Henning Schulzrinne <[email-masked]>
Date: Mon, 24 Sep 2007 10:53:11 -0400

My general preference is to avoid overloading or implicit  
assumptions. There are three possibilities:

(1) use the <note> field in device for a human-readable description  
("ethernet switch")
(2) add a device type indication to the <device> field, with the  
difficulty of enumerating devices (this differs a bit from draft-ietf- 
simple-prescaps-ext, as that is more meant to describe the  
communication device, not a network device)
(3) add an indication to PIDF-LO that indicates the proximity to the  
user or end device

(3) seems cleanest.

For identifying the device, IP addresses are clearly not good, due to  
their lack of uniqueness and temporal stability. (I could easily have  
two devices that both answer to 192.168.0.1, such as a device in my  
office and at home.) A UUID seems most appropriate.

Henning

On Sep 24, 2007, at 9:39 AM, Hannes Tschofenig wrote:

> LLDP-MED has a "what" element, describing if the location of the  
> client itself, of the DHCP server or of the network element closest  
> to the client is provided. This seems to be useful information, but  
> where to put this in a PIDF document?
> "
>
> Furthermore, in a discussion with Henning and James about the  
> update of the PIDF-LO profile draft (aiming to reflect the feedback  
> regarding the usage of RFC 4479) we came across two questions:
> Regarding the later aspect we learned that location information  
> should be placed into the <device> element when a LIS creates it  
> (rather than using <tuple> or <person>).
>
> The <device> element has a mandatory element, the <deviceID>, that  
> has to contain a URN. Now, what information should we put in there?  
> IP address, MAC address, anything else?
>
> For (a) we indicated that the 'entity' attribute inside the  
> <presence> element, see Section 4.1.1 of RFC 3863, contains the  
> entity to which the location refers to.
>

---

From: "Winterbottom, James" <[email-masked]>
Date: Mon, 24 Sep 2007 16:03:56 -0500

The address that you can be sure the LIS gets in many cases will be the
IP address. For example if I am connected to an ATM over DSL service
then I am using PPP, so MAC address is visible at the LIS, I absolutely
do not want to include the PPP user name in the <person> or <device>
elements.

Cheers
James

> -----Original Message-----
> From: Hannes Tschofenig [mailto:[email-masked]]
> Sent: Tuesday, 25 September 2007 12:01 AM
> To: Karl Heinz Wolf
> Cc: GEOPRIV
> Subject: [Geopriv] Re: What location does a PIDF-LO refer to?
> 
> Hi
> 
> Karl Heinz Wolf wrote:
client
> >> Furthermore, in a discussion with Henning and James about the
update of
> >> Regarding the later aspect we learned that location information
should
> >> The <device> element has a mandatory element, the <deviceID>, that
has
> in there since there are more choices in the general case.

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