RE: [bt-spec] BTP Issue 48 : completion of enrollment

[Peter Furniss <peter.furniss@choreology.com>]

 

BTP Issue 48 : completion of enrollment

Submitter: Mark Little, HP
Category: minor technical
Submitter's identification: #17
Description:
What does "or will be completed by ENROL messages sent in relation to the CONTEXT_REPLY" on page 30, first paragraph refer to?

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As specified for completion-status = "related".  Occurs in one-shot (and some other cases) - an application request & CONTEXT is sent out. If this causes work to be done that requires the enrolment of an Inferior (which is normal for BTP of course), the ENROL comes back with the application reply. This will be an ENROL/no-rsp-req, since the Inferior doesn't want the ENROLLED to be sent back to it. However, provided that the necessary enrolment is successful, the assertion can be made that

 

In this case, the checking requirement is that provided the enrollment succeeds, then all Inferiors implicated by the earlier transmission of the CONTEXT have been enrolled. One way this might be implemented would be for an interceptor to take the CONTEXT_REPLY (from the application reply's header), extract any ENROL's, substitute its own address as the reply-address  and change the response-requested flag to true, and issue the ENROL to the superior in question. If an ENROLLED is received back for all such ENROLs ( more than one is improbable in practice), then the enrollments are all safely done, and the application response can be returned. (The CONTEXT_REPLY is of no further use). If the ENROL's fault, then whatever it was did this must somehow make sure the transaction does not confirm, as there a floating wold-be Inferiors out there.

 

Does this need an explanatory note here ?