SML / SMP / NAPTR question

["Pim van der Eijk" <pvde@sonnenglanz.net>]

I'm prototyping some BDX and other technologies and ran into the following issue:

 

In SML, one URI pattern is defined, to be used when a retrieving metadata for a specific document type:

 

http://<hash over recipientID>.<schemeID>.<SML domain>/<recipientID>/services/<documentType>

 

Section 2.2 of the PEPPOL SMP suggests SML/SMP also provide an interface to retrieve a ServiceGroup for a given Participant Identifier.  In this case we don't know the document type.  What is the URI pattern to use to retrieve a ServiceGroup and where in SML or in SMP is it defined ?

 

When using NAPTR "U" records, the second occurrence of "recipientID" in the URI would no longer needed as the record can directly reference a recipient-specific resource on the metadata server, it is not just a domain.  That is an improvement.  But that raises the question how to combine that referenced resource identifier with a variable documentType.  Can the regular _expression_ be used? 

 

The  "/services/" substring in the URI seems to be unnecessary in SML already.