8 Mechanisms for transfer of Service Data between Application Server and the HSS for AS interoperability

29.3643GPPIP Multimedia Subsystem (IMS) Application Server (AS) service data descriptions for AS interoperabilityRelease 17TS

8.1 Sh procedures to transfer Service Data

Standardized procedures of the Sh interface described in 3GPP TS 29.328 [18] are used between the AS and the HSS to access and update the Service Data attached to a user.

To aid a proper interoperability between AS, a certain number of additional recommendations are hereafter described:

– After an AS has created or modified Service Data, it shall update the Service Data in the HSS with the Sh- Update procedure.

– After an AS has downloaded Service Data from the HSS for a given user, it should subscribe to the notification of Service Data with the Sh-Subs-Notif

– If the AS has subscribed to the notification of Service Data, the AS shall support the Sh-Notif procedure to be informed of the changes in the Service Data.

– HSS and AS shall use Sequence Number information to ensure data synchronization

8.2 Base64 data encoding

As the Service Data for the binary option are in binary format, it shall be transcoded in a character mode to be transferred over the Sh interface.

The standard used for this transcoding is the base64 encoding mechanism as described in IETF RFC 2045 [19].

In reference to 3GPP TS 29.328 [18], Annex D, Tables D.1 and D.2, MMTEL Service Data used for AS interoperability is defined according to Table 8.2-1 regarding the XML schema for the Sh user profile interface.

Table 8.2-1: Data type for Service Data in the XML schema for the Sh user profile interface

Data type	Tag	Base type	Comments
tServiceData	ServiceData	String	Base64 encoded according to RFC 2045 [19]