subscription identifiers

Jon,

I've updated the content of 

   http://simp.mitre.org/drafts/sdf.txt

I've changed the description of the subscribe operation in the
document.  I offer the description as proposed text for specifying
subscription identifiers in CPIM when they become separated from
transaction identifiers.

Additionally, following the results of the discussion on the
notification operation, in which no wrapper appears to be needed, the
CPIM Subscription Data Format document specifies the use of XML syntax
for the content that can be signed.

John

2. The SUBSCRIBE Operation

The SUBSCRIBE operation is used to request that a service deliver PRES­
ENCE INFORMATION as specified in [CPIM].  As a side effect of a success­
ful SUBSCRIBE request, a PRESENCE SERVICE MUST initiate a NOTIFY request
that delivers the current PRESENCE INFORMATION contained by the PRESEN­
TITY targeted by the SUBSCRIBE request.

If the SUBSCRIBE request specifies a non-zero subscription duration, a
successful response MUST include the duration of the SUBSCRIPTION
granted by the service.  If the SUBSCRIBE request does not contain an
identifier, the PRESENCE SERVICE must return an identifier for the sub­
scription as part of a successful response.  As long as the SUBSCRIPTION
has not lapsed, when the PRESENCE INFORMATION changes, the PRESENCE SER­
VICE MUST initiate a NOTIFY request that delivers the new PRESENCE
INFORMATION to the SUBSCRIBER.

The triple consisting of an identifier, and the names of a WATCHER, and
a PRESENTITY uniquely identify a SUBSCRIPTION.

A SUBSCRIPTION can be canceled with a SUBSCRIBE request that specifies
the SUBSCRIPTION's identifier and a duration of zero seconds.  A SUB­
SCRIBER cannot hold more than one SUBSCRIPTION.  A PRESENCE SERVICE MUST
cancel a SUBSCRIPTION from a SUBSCRIBER when that SUBSCRIBER issues a
SUBSCRIBE request with a non-zero duration that does not contain the
original SUBSCRIPTION's identifier.

PRESENCE INFORMATION can always be fetched by issuing a SUBSCRIBE
request with a zero duration and no subscription identifier.  If a SUB­
SCRIBE request specifies a zero subscription duration, a successful
response MUST NOT contain any duration information.



  [reminder: [email protected] for non-technical discussions, please]