Application Servers can store their service data on the HSS through the Sh
interface as transparent data, meaning that the HSS may not be aware of the structure and the semantics of this data, only the Application Server has this knowledge. Standardizing the data formats would facilitate interoperation among Application Servers supplied by the same, or different, vendors. These Application Server vendors may be primary and secondary suppliers of the same service provider within a service provider's IMS network. This is especially true for the Multimedia Telephony supplementary services that can achieve a wide deployment and are here addressed by this specification.
This specification standardizes the structure and the coding of the service data that are transported over the Sh
interface between an Application Server supporting Multimedia Telephony supplementary services as defined in TS 22.173
and the HSS. Two optional formats are specified. One is based on a binary coding of the service data and supports the subset of MMTEL services corresponding to PSTN/ISDN and CS supplementary services. The other uses
an XML format and supports the full set of MMTEL Services.