Comment:

How does FHIR fit as part of a broader architecture landscape? How does fit within HL7 SAIF specification? Many organisations find it useful to separate logical from implementable specifications as an insurance policy against change. It would be highly valuable to position FHIR as part of such a framework, which would also allow better inclusion of behaviour and policy constraints. Possibly section 3.1 can point to the HL7 SAIF