Comments on CPIM draft 03

Jon,

Thank you for updating the CPIM draft.  I am particularly happy to see
the current draft has a consistent story on URIs, and the Presence
Service DTD no longer includes an unsubscribe operation.

I notice that the format of the document has changed, so that it is
not obvious which sections of text remain the same.  You can
facilitate better feedback from us by identifying changes, and the
easiest way to do that is to send to the list a unified diff, "diff
-u", which compares the source for version 02 with the one for version
03.

Following Hiroyasu's suggestion, I will defer comments on notification
authentication.  Enclosed are comments that are not ordered by
importance.

1. The title of Section 2.1 is now "Overview", but I think the
   previous title of "Overview of Instant Messaging Service" is
   better.  If "Overview" is really the desired title, than it should
   also be the title of Section 3.1.

2. On Page 11, the diagram for the unsubscribe operation is
   erroneously formated.

3. The unsubscribe operation has been removed, but Page 11 shows an
   example of it.  I suggest changing that section to:

      The application may prematurely cancel a subscription by
      invoking the subscribe operation with a duration of zero, e.g.,

             +-------+                    +-------+
             |       |                    |       |
             | appl. | -- subscribe 0 --> | pres. |
             |       |                    | svc.  |
             +-------+                    +-------+

             <subscribe watcher='pres:[email protected]'
             target='pres:[email protected]'
             duration='0' transID='3' />

4. On Page 13, Paragraph -2 contains the phrase "Step 4.3 above does
   not occur".  Where is Step 4.3?  I think it refers to the last
   doubly indented paragraph on the page, so these paragraphs must be
   labeled. 

5. Section 4.3.2 on Page 17 has the sentence:

      End-to-end security for presence notifications and subscriptions
      could be provided by any MIME-based security mechanism.

   How can one provide end-to-end security for subscription operations
   without an agreed upon common format for the operations?  How can
   one provide end-to-end security for notification operations without
   an agreed upon convention for identifying presence services?

6. Section 3.4.3 and Section 3.4.4 refer to a subscription ID, but
   never define what it is.  For an unsubscribe operation, I assume
   the subscription ID is the transID of the subscription operation
   that established the subscription, while the the subscription ID
   for a fetch operation is any transID not currently in use.  The
   assumptions on IDs must be explicitly stated.

   Of course, we may want to be explicit about the role of
   identifiers, as suggested by Thanos in

      http://www.imppwg.org/ml-archive/IMPP-WG/200207/msg00007.html

Thanks,

John



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