Re: [Sip] draft-ietf-sip-location-conveyance - Question about potential usage of the Geolocation header

[Bartłomiej Kołakowski <b.kolakowski at plus.pl>]

Thanks for reply Brian.
Probably we'll go for the SUBSCRIBE/NOTIFY option. We'd rather keep cell ids inside our network, but anyway it's not really possible (see Google's My Location). So far we won't have any 3rd parties connected to IMS though.

Do you know if there is any standard to include a cell-id into PIDF-LO?

Bartek


-----Original Message-----
From: Brian Rosen [mailto:br at brianrosen.net] 
Sent: Wednesday, August 13, 2008 10:24 PM
To: Bartłomiej Kołakowski; draft-ietf-sip-location-conveyance at tools.ietf.org; sip at ietf.org
Subject: RE: draft-ietf-sip-location-conveyance - Question about potential usage of the Geolocation header

You can use the "HELD" protocol, rather than a SIP SUBSCRIBE/NOTIFY for the dereference, if that makes it seem simpler to you.  SUBSCRIBE/NOTIFY is quite simple, and most devices and services implement it for other reasons.

We have discussed using cell-id as a representation mechanism, but have been told, many times, that operators will not divulge location of cell ids beyond the immediate network, which makes this form of location entirely
unsuitable for the range of applications we envisioned.   If you have
different information, please share it.

On the other hand, even if we did allow cell id as a form of location, it would be inside a PIDF-LO, and thus would need to be in a body.

I don't think putting actual location in the header is a good idea, as it cannot be protected against inadvertent disclosure.  That would be a problem in the IETF.

Brian
________________________________________
From: Bartłomiej Kołakowski [mailto:b.kolakowski at plus.pl]
Sent: Wednesday, August 13, 2008 10:04 AM
To: draft-ietf-sip-location-conveyance at tools.ietf.org; sip at ietf.org
Subject: draft-ietf-sip-location-conveyance - Question about potential usage of the Geolocation header

Hello,
I have got such concern regarding location conveyance in SIP messages: I am designing IMS Appilcation Server, acting as a proxy, that would query network elements for location information. As you wrote proxies cannot insert message body, so the only way is to provide location by reference.
This requires appling SUBSCRIBE-NOTIFY mechanism, which makes the architecture of the solution quit complex.
In order to make it simpler I thought about including location information as locationValue inside the Geolocation header. In fact we do not need location represented with coordinates, but with cell-id (that's mobile network). PIDF-LO does not support it, but maybe inside a header that would be possible? There would be also an issue in indicating loaction target whose location is included (we plan to include both A and B parties location). Geolocation header would look like this:
Geolocation: {cell-id-3gpp}
;location-target="bob at plus.pl";inserted-by="las at plus.pl" 
What do you think about souch a usage of Geolocation header, maybe you could give us some other solution? 
Thank you in advance,
Bartłomiej Kołakowski
Service Solutions Architect
Service Development Support Department
Polkomtel S.A
tel. 601131509 

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