[Serusers] Re: problem for using the latest pa module

Klaus Darilion klaus.mailinglists at pernau.at
Mon Feb 9 18:15:04 CET 2004

Hi Jamey!

Thanks for the information. One of my students here at the university 
tries to implement a system where you can watch mobile user running 
around and call them by clicking on the moving point at the map - all 
with SIP. Currently we produce the location information at the mobile 
client (ipaq + xlite) by reading the GPS data from a bluetooth GPS receiver.

On the other side, we would like to have a Windows based client, which 
uses the RTC API. So the idea was to include the GPS information into 
the presence by using the "user-provided presence info" (like 
"x=123;y=456" instead of "i'm at lunch and come back at 2:30"). 
Nevertheless, therefore it would be necessary that the RTC API accepts 
the notficiations from ser.

The RTC api sends its notifieys as application/xpidf+xml, not as 
application/cpim-pidf+xml. Is this the same format with a different 
name? I tried to find the definition of them, but I found several 
outdated drafts. I took a closer look at the drafts from the impp 
working group, but for example i couldn't find the definition of the 
<presentitiy> tag. Can you point me to a document which describes the 
format used by the RTC. Btw: which format uses the sipc or other 
commerical SIP-based IM applications?

I also found no description of adding the exact geographical location 
into the presence information in a more generic way (not the workaround 
described above). Have you ever thought of this (as the columns are 
already defined in the database tables)? E.g. it could be a dedicated 
tag or an attribute in the location tag.


Jamey Hicks wrote:
> Klaus Darilion wrote:
>> Hi Jamey!
>> Im interested in the presence agent module, especially in including
>> geographical user information into the presence data.
>> What is the body type of the publication/notifications? Is it XML based
>> presence like used by Windows Messenger and Kphone? Is this format
>> defined somewhere? Is this the same as this old draft?
>> http://www.iptel.org/info/players/ietf/presence/outdated/draft-rosenberg
>> -impp-pidf-00.txt
>> The presentity table includes x and y colums? Are these to represent the
>> geographical location of the publisher?
> Hi Klaus,
> The body type is application/cpim-pidf+xml with a couple extensions 
> modeled on geopriv and civil location.  The same body type is accepted 
> by the code that handles PUBLISH and updates the database.  The NOTIFY 
> messages are generated from that.  We have an 802.11 location tracking 
> system that generates PUBLISH messages that include site, floor, room, 
> x, y and radius of the position estimate.  Our location tracking service 
> yields roughly office-level resolution for the two floors of our 
> building that we occupy.  The position data is for the client device 
> from which a user is registered.  We also have PHP code for a presence 
> portal that lets users update their location manually if no location 
> service is available or if they wish to override the location provided 
> by the location service.
> The presence agent still needs some work -- it currently allows anyone 
> to  subscribe.  I have mostly coded support for the watcherinfo event 
> package and for xcap access to presence-lists, so that users can be 
> notified when a new person requests to subscribe to their presence info 
> and so that users can use xcap to authorize/deny those requests.  I have 
> been working with Xiaotao Wu at Columbia to debug that against the sipc 
> user agent and I've been adding code to linphone.  It would be great if 
> someone wants to add similar support to kphone.  I may get to kphone but 
> I have a lot on my plate right now.
> The other thing that the presence agent should have with respect to 
> physical location is a way for a user to specify the resolution of the 
> location information to be shared with other users.  For example, I 
> might want to let people know I'm on the 12th floor here but not which 
> office I'm in.
> Another problem with the presence agent is that Windows Messenger does 
> not accept the NOTIFY messages, so none of your contacts looks to be 
> online.  I'm not interested in supporting a UA that does not support the 
> internet draft standards but if minor tweaks would make this work that 
> would be OK.
> The final issue that comes to mind with the PA is that it is set up to 
> aggregate presence for all user agents.  It handles SUBSCRIBE and 
> PUBLISH, and it generates NOTIFY.  It gets basic online/offline status 
> from the usrloc module but depends on the UA or other presence agent to 
> PUBLISH more detailed information.
> I hope this is helpful.  I am planning to write a document that outlines 
> how this works and what is needed from UA's.  I imagine that review and 
> revision of that document will lead to changes in the PA implementation 
> to make the whole system work better.
> Jamey
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