CCITT Rec. I.310 (11/1988) – ISDN – NETWORK FUNCTIONAL PRINCIPLES
1 General
    1.1 Basic philosophy of the functional description
    1.2 Services supported by an ISDN
    1.3 Generic description of required capabilities
2 Objectives of the functional description of the ISDN
3 Generic description model
    3.1 General concepts
    3.2 Static description model
    3.3 Dynamic description model
4 Use of generic description model
    4.1 Identification of ISDN global functions
    4.2 Identification of ISDN elementary functions
    4.3 Identification of ISDN executive processes
5 Functional realization of basic service requests
ANNEX A
    A.1 List of identified basic elementary functions and additional elementary functions (EFs) for the ISDN
    A.2 Short description of elementary functions
ANNEX B – Descriptions of identified functional components (FCs) for the ISDN
    B.1 Hold invocation
    B.2 Retrieve
    B.3 Join
    B.4 Split
    B.5 Transfer
    B.6 Notify
    B.7 Enquire
    B.8 Adjourn
    B.9 Restart
    B.10 Monitor
    B.11 Reroute