The two transport layers are covered in the following documentations.
C.9 SIF and Web Services
With the addition of Web Service support in the SIF v2.5 specification, it is now possible to write a “pure” SIF web service which:
• Supports a defined SIF Application WSDL interface for receiving asynchronous, Events, Requests and Response methods over the SOAP transport
• Acts as a web client of the a set of ZIS web services, which also support SIF-specified WSDL interfaces over the SOAP transport, and which together encapsulate the ZIS functionality
• Can seamlessly and transparently interoperate with other SIF applications, whether they are web services themselves, or pre-existing SIF v2.x HTTP/S based applications.
The details of this support are contained in the SIF Global Web Services Implementation Specification volume of this release.