scope:

This ETS defines a network-internal interface for the provision of ISDN packet-mode services. The term ISDN packet mode services is defined in such a way as to include both case B (ISDN Packet Mode Bearer Services (PMBS)), and case A (PSPDN services), as defined in ETS 300 007 [20]. If a specific implementation alternative for the provision of PMBS and PSPDN is used in an ISDN or a Global System for Mobile communication (GSM) Public Land Mobile Network (PLMN), this ETS applies. The implementation alternatives and the exact location of the interface are described below. In CCITT Recommendation I.324 [6] local Connection Related Function (CRF) and Packet-Handling Function (PHF) are defined as being involved in the provision of PMBS. The local CRF includes the Exchange Termination (ET). Two basic implementation alternatives are mentioned in subclause 3.1.2 of CCITT Recommendation I.324 [6] and in ETS 300 007 [20]: