1、CEPT T/CS*b-OI*E 232b4I4 0005263 I 0 TCS68-01 Page E 1 Recommendation T/CS 68-01 (Brussels 1980, modified inVienna 1982, Montpellier 1984 and Odense 1986) INTRODUCTION, FIELD OF APPLICATION AND BASIC FUNCTIONS FOR DIGITAL TRANSIT EXCHANGES Recommendation proposed by Working Group T/WG 11 “Switching
2、and Signalling” (CS) “The European Conference of Postal and Telecommunications Administrations, considering that - transit exchanges are currently being introduced for both analogue and digital telephone networks, - the evolution of telecommunication networks toward an integrated services digital ne
3、twork (ISDN) is expected in many countries, the study of requirements for digital transit switching will take into account developments of the ISDN and results will be reflected in the Recommendations, recommends that the members of the CEPT, when introducing digital transit exchanges, take account
4、of and give effect to the following set of switching systems specifications.” Notes. CCITT Recommendations take into account most of those ideas developed in the preceding CEPT Recommendations and the final versions established in CCITT are supported by CEPT member Administrations. - It is helpful f
5、or writers and readers of Recommendations on digital transit exchanges to have the information presented in a uniform way in the two sets of Recommendations to facilitate concentration on specific issues from the CEPT point of view and progress in areas not covered so far by CCITT; in order to limit
6、 as much as possible the redundancy, however, the present text has been reorganized with the aim of emphasizing the differences with respect to CCITT Recommendations. The reader is referred to CCITT Recommendation Q.501 l, to which this Recommendation is identical, except for the additions and modif
7、ications indicated below. The section references (indicated 0) are to Q.501 i. 0 1; the CEPT series of Recommendations is: T/CS 68-01 2 instead of Q.501 i T/CS 68-02 4 instead of 4.502 3 T/CS 68-03 6 instead of 4.503 5 T/CS 68-04 SI instead of 4.504 7 T/CS 68-06 lo instead of 4.506 9. Note. CCITT Re
8、commendations Q.505 li and 4.507 12 are not considered. $3; Add at the beginning: The fundamental purpose of a digital transit exchange is circuit switching. The functions which may be required to fulfil this purpose are described in this Recommendation. There is no intent to describe hardware, soft
9、ware of firmware implementations, and no constraint on the design of the functions, either individually or collectively, is implied. In integrated services digital networks, some packet handling facilities and/or information processing functions might also be provided in the digital transit exchange
10、. The general objectives of the exchange are: - to set up and clear down connections controlled by signalling systems or control-initiated by man-machine - to perform as specified in Recommendations T/CS 68-02 4, T/CS 68-03 6, T/CS 68-04 8 and T/CS 68-06 lo; - to work in harmony as a network element
11、 with other exchanges conforming to the T/CS 68 Group of Recommen- dations, with digital local and combined exchanges (see T/CS 62 Group of Recommendations: T/CS 62-01 13, 62-02 14, 62-03 15, 62-04 16, 62-06 17) and with existing analogue exchanges; communications ; I Edition of September 15, 1986 t
12、 CEPT T/CS*b-OL*E m 232bYLY 00052bY 3 m rm 68-01 E Page 2 - to provide at least a specified minimum of operation, maintenance and diagnostic information as required for - to be a component in the IDN and to put minimal constraint on the development of the ISDN; - to act as a node in the timing/synch
13、ronisation system; - to work with the recommended CCITT, CEPT and other signalling system(s) as required because of its position Certain other objectives may be optional: - to control ancillary equipment; - to provide additional operation, maintenance and diagnostic information for eficient operatio
14、n of the exchange - to provide accounting and/or charging information; - to provide operator services; to act as a timing/synchronization source. 0 3.2.1; add at the end; The exchange at the head of the synchronisation hierarchy may contain the national timing source or may be directly slaved from i
15、t. 0 3.2.2; add after the first paragraph: For telephony, a path will have the external appearance of a bidirectional connection. 0 3.2.3; replace by the following: The signalling function includes reception of call-related and other information, its translation into information for control and othe
16、r functions, and transfer of information to subscribers and networks, as required. It includes inter-exchange signalling, which is mainly related to the inter-exchange links. The signalling function may involve common channel and/or channel associated signalling. Q 3.2.4; replace the last paragraph
17、by the following: Control includes generation of charging information, running diagnostic routines on its own and other functions, and generating trafic and maintenance statistics, if required. 0 3.4; add a reference to T/CS 54-12 is). 3.5; add at the end: See also Recommendation T/CS 50-01 19. Thes
18、e functions involve interfacing between exchanges and operating staff and/or operation and maintenance centres (OMCs). Included may be fault recording and diagnosis, provision of man-machine communication, collection of information concerning the exchange and network operations (trafic measurement,
19、network management), accounting, etc. eficient operation (see Recommendation T/CS 68-06 171; in the international or national network. and associated transmission, signalling, timing and ancillary equipment; 0 3.6; add a new section: 4 HARMONISATION The T/CS 68 Group of Recommendations aims to speci
20、fy parameters as a basis for functional harmonisation. At present, these Recommendations are not sufficiently detailed to give satisfactory answer to all questions concerning harmonisation. This requires further study. REFERENCES 11 2 3 4 SI 6 CCITT Recommendation 4.501. Introduction,jeld of applica
21、tion and basic functions for digital transit exchan- ges. TICS 68-01 Recommandation. Introduction,jeld of application and basic functions for digital transit exchanges. CCITT Recommendation 4.502. Interfaces for digital transit exchanges. TICS 68-02 Recommendation. Interfaces for digital transit exc
22、hanges. CCITT Recommendation 4.503. Connections, signalling, control, call handling and ancillary functions for digital transit exchanges. T/CS 68-03 Recommendation. Connections, signalling, control, call handling and ancillary functions for digital transit exchanges. Edition of September i 5, 1986
23、CEPT T/CS*b8-Ol*E 232b414 00052b5 5 TICS 68-01 E Page 3 CCITT Recommendation 4.504. Performance and availability design objectives for digital transit exchanges. TICS 68-04 Recommendation. Performance and availability design objectives for digital transit exchanges. CCITT Recommendation 4.506. Opera
24、tions and maintenance functions for digital transit exchanges. TICS 68-06 Recommendation. Operations and maintenance functions for digital transit exchanges. CCITT Recommendation Q.505. Exchange measurements. CCITT 4.507 Recommendation. Transmission characteristics. T/CS 62-01 Recommendation. Introd
25、uctionjeld of application and basic functions for digital local and combined exchanges. TICS 62-02 Recommendation. Interfaces for digital local and combined exchanges. TICS 62-03 Recommendation. Connections signalling, control, call handling and ancillary functions for digital local and combined exc
26、hanges. TICS 62-04 Recommendation. Performance and availability design objectives for digital local and combined exchanges. TICS 62-06 Recommendation. Digital local and combined exchange operation and maintenance functions. TICS 54-12 Recommendation. Traffic measurements. TICS 50-01 Recommendation. Maintenance philosophy for digital and mixed networks. Edition of September 15, 1986
