Re: Subscription Data Format

[email protected] wrote:
> I have become very concerned about making subscription requests work
> through gateways between APEX and SIMPLE systems.
> 
> The subscription data format I proposed at
> 
>     http://simp.mitre.org/drafts/sdf.txt
> 
> was an attempt to make a concrete realization of what was in the CPIM
> document that can be signed.  I spent some time reading the presence
> proposals for APEX and SIMPLE.  The APEX proposal at
> 
>     http://www.ietf.org/internet-drafts/draft-ietf-apex-presence-06.txt
> 
> contains information exchanges that roughly follow the CPIM document,
> so a common subscription data format based on CPIM should not be
> difficult for APEX, however, the case for SIMPLE is quite different.
> The SIMPLE documents include one that describes a subscription data
> format in
> 
>  
> http://www.ietf.org/internet-drafts/draft-ietf-simple-winfo-format-02.tx
> t

That is totally false. This document is not a subscription data format. 
It is used in NOTIFY requests for the wathcer information package. See 
below.


> 
> and describes its use in
> 
>  
> http://www.ietf.org/internet-drafts/draft-ietf-simple-winfo-package-02.t
> xt
> 
> The SIMPLE subscription data format is designed to support a
> subscription state machine that includes states that cannot be reached
> using the CPIM model.  A SIMPLE client attempting to subscribe to an
> APEX presentity might see surprising, and non-intuitive results.

The above documents do not define core presence. The core presence 
specifications, in line with the CPIM model, are specified in:

http://www.ietf.org/internet-drafts/draft-ietf-simple-presence-07.txt

These easily map to CPIM, an exercise that is documented in:

http://www.ietf.org/internet-drafts/draft-ietf-simple-cpim-mapping-01.txt

and was just updated this week, in fact.

The above documents you reference allow or reactive authorization, 
whereby if someone subscribes to me, I can get an alert (using the event 
package above), and then go and specify an authorization policy for that 
subscriber. Rather than just specifying that you "get an alert when 
someone subscribes to you", we modelled the subscription state machine, 
allowing you to get alerts on various other changes in someones 
subscription to you. The above document is therefore carried in 
notifications, NOT subscriptions.

Note further that reactive authorization is well outside the scope of 
CPIM, as we elected not to cover things of the "intra-domain" nature.

-Jonathan R.
-- 
Jonathan D. Rosenberg, Ph.D.            72 Eagle Rock Avenue
Chief Scientist                         First Floor
dynamicsoft                             East Hanover, NJ 07936
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http://www.dynamicsoft.com




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