The scope of this Technical Specification is to provide a specification for interworking between the ISDN Application Service Element (ASE) protocol for supplementary services and the Mobile Application Part (MAP) protocol on MAP D-interface protocol for handling of supplementary services within the digital cellular telecommunications system (Phase 2 ). This version of the specification includes the interworking for the Call Completion to Busy Subscriber (CCBS) service between the ISDN CCBS-ASE and MAP. The MAP protocol for CCBS service is specified in GSM 09.02. The ISDN CCBS-ASE protocol is specified in ETS 300 356-18. The ISDN CCBS-ASE protocol is also commonly referred to as the SSAP protocol in GSM 03.93. This specification clarifies the interworking within the HLR between these protocols for the Call Completion to Busy Subscriber (CCBS) service. Section 4 describes the mapping between MAP application layer messages and SSAP application layer messages Section 5 describes the mapping between MAP message parameters and SSAP message parameters. Section 6 describes the SCCP layer addressing for messages on the SSAP interface. It also describes the mapping of the messages at the TC transaction sublayer between the MAP D and SSAP interfaces.
