Internet Standards/CD2.mdf/ccitt/1992/i/i220.asc

Text File | 1993-06-28 | 5KB | 1,022 lines

Recommendation I.220 - Common dynamic description of basic

telecommunication services



1.    Introduction



    This Recommendation provides the dynamic description of basic telecommunication services. The dynamic
description for basic telecommunication services using the circuit-mode means of service establishment/dis-
establishment is provided in section 2.  The packet-mode description is for further study.



    The dynamic description shows the flow of events, and states within the service, in a time sequenced format and
identifies all possible actions relevant to the service as perceived by end-users.



    Although the service is described from the end-user perspective it does not concern details of the human-to-
machine interface itself. In addition, the service description considers the network as a single entity. For example, infor-
mation flows between nodes within the network are not shown.



    End-user perceptions of the service are shown in terms of "user/network" interactions. Internal network actions are
included whenever they are or can be perceived by an end-user(s) during the operation of the service, and as required
by SDL drawing rules.



    The terminology and the meaning of the "user/network" interactions are provided in Annex A. The means for devel-
oping dynamic descriptions, e.g. the SDL symbols and their usage, is further elaborated in RecommendationI.210.



Note - In the development of the circuit-mode dynamic description, the bearer services - speech, 3.1 kHz audio, unre-
stricted, and the teleservices - telephony, Teletex, Telefax 4, mixed-mode and Videotex were considered. Others are for
further study.



2.    Circuit-mode dynamic description of basic bearer and teleservices





     (BASIC CALL PROCESS)































































































































































































(BASIC CALL PROCESS

Macro definition outgoing call)

























































































Note 1 - This is an event which may occur at the S/T reference interface and can be reflected at the user interface.







(BASIC CALL PROCESS

MACRO DEFINITION INCOMING CALL)

































































































































































































Note 2 - This is an event which may occur at the S/T reference interface but is not reflected at the user interface.























































































































































































































































































































































































































































ANNEX A



(to Recommendation I.220)



Terminology for "user/network" interactions





    SETUP          Interaction across the "user/network" interface regarding  a service request.



    REPORT      Interaction across the "user/network" interface regarding  alerting of the users terminal function, inter-
working   with a non-ISDN network, or routing progress.



    CONNECT      Interaction across the "user/network" interface regarding  completion of circuit cut-through.



    DISCONNECT    Interaction across the "user/network" interface

regarding a user who has disconnected or user A cannot be connected (e.g.  Busy) to user B.



    RELEASE      Interaction across the "user/network" interface regarding                        freeing of resources
associated with the call/connection,                        such as call references and channels.



    NDUB          Network determined user busy.



    UDUB          User determined user busy.