1、W 23264l14 0009073 5 Page 1 Recommendation T/S 62-20 (Edinburgh 1988) DIGITAL EXCHANGE CONNECTIONS, SIGNALLING AND ANCILLARY FUNCTIONS Recommendation proposed by Working Group T/WG 11 “Switching, Protocols and Switching” (SPS) Text of the Recommendation adopted by the “Telecommitnicatioris” Commissi
2、on : “The European Conference of Post and Telecommunications Administrations, secommends that the members of the CEPT, when introducing digital local, combined transit and international exchanges, take account of and give effect to the following specifications on Connections, Signalling and Ancillar
3、y Functions.” The reader is referred to CCITT Recommendation Q.522 I to which this Recommendation is identical, except for the addition and modifications indicated below. The section references (indicated ) are to 4.522 I. Edition of Janoary 15. 1989 / y. U 2326434 O009074 7 TIS 62-20 E Page 2 52.2.
4、7. : Add the following sections: 2.2.7. Type V exchange connectiofi (Figure 5 (TIS 62-20) This connection allows an unrestricted transfer of user informations via two channels at 64 kbit/s. The signalling handling and exchange control functions perform the routing of both B channels from a basic of
5、primary subscriber access to a primary/secondary network access. The mixture of 64 kbit/s channels and 2 x 64 kbit/s channels on a given primary access should be given. Whether time slot sequence integrity (TSSI) is provided or not on a per call basis requires further study. This connection may not
6、be supported by all exchanges. This connection is characterized by: - information trnnsfer attributes mode : circuit rate: 2 x 64 kbit/s capability: unrestricted digital information establishment: switched-semi-permanent symmetry: bidirectional-symmetric configuration: point to point-uniform structu
7、re: 8 kHz integrity - access attributes User access Network access Access channel and rate 2 x BI64 informations network Signalling D/16-64 Digital circuit (sl) Digital circuits with access to digital switched Access protocol (1) See type I See type I (For signalling access to digital switched netwo
8、rk) * * Further study is required for information trnnsfer protocol or access to PSPDN. - other attributes Further study. Local or combined exchange -1 - I“ Digital subscriber access I I Info Layer 1 64 kbit/s functions Info circuit switch Layer 2 functions 2xB - (SI D r -= 1 I Digital circuits with
9、 access to digital switched network s Handling and exchange control functions I I 1 I Figure 5 (TIS 62-20). Type V exchange connection. - I -P -. Edition of January 15, 1989 - I 232b414 O009075 9 W TIS 62-20 E Page 3 2.2.8. Type VI excharige connection (Figure 6 (TIS 62-20) This connection allows an
10、 unrestricted transfer of user informations via a HO channel. The requirement for 6 x 64 kbit/s connections can be satisfied by establishing 6 separate 64 kbit/s semi-permanent connections, each of which would be set up to preserve the sequence with the other slots forming the 6 x 64 kbit/s connecti
11、on. The mixture of 64 kbit/s channels and HO channels on a given primary access requires further study, so the allocation of the HO channels within the 2048 kbit/s frame structure is a national option. The circuit switch stage(s) rate is for further study. This connection may not be supported by all
12、 exchanges. This connection is characterized by: - information transfer attributes mode : circuit rate: 384 kbit/s capability: unrestricted digital information establishment: semi-permanent symmetry: bidirectional-symmetric configuration: point to point-uniform structure: 8 lz integrity - access att
13、ributes I I User access Access channel and rate informations Signalling For further study Access protocol For further study - other attributes Further study. Digital subscriber access Network access Digital circuits with access to digital switched nehvork For further study 1 For further study I HC -
14、 Local or combined exchange -1 - I- Layer 1 functions Il I I I I and exchange control functions L- I Figure 6 (TIS 62-20). Type VI exchange connection. Digital circuits with access to digital switched network Edition of January 15, 1989 ,=- .-. , m 2326414 O009076 O m Access channel and rate informa
15、tions Signalling Access protocol TIS 62-20 E Page 4 User access Network access 1920 kbit/s For further study For further study Digital circuits with access to digital switched network For further study For further study 2.2.9. Type VII exchatige connection (Figure 7 (TIS 62-20) This connection allow
16、s an unrestricted transfer of user informations via a H1 channel at 2048 kbit/s. The requirement for 30 x 64 kbit/s connections can be satisfied by establishing 30 separate 64 kbit/s semi- permanent connections, each of which would be Set-up to preserve the sequence with the other slots forming the
17、30 x 64kbit/s connection. The circuit switch rate requires further study. This connection may not be supported by all exchanges. This connection is characterized by: - information transfer attributes mode : circuit rate: 1920 kbit/s capability: unrestricted digital information establishment: semi-pe
18、rmanent symmetry: bidirectional-symmetric configuration: point to point-uniform structure: 8 kHz integrity - access attributes Digital subscriber access I *q I 1 I Info - Layer 1 Circuit - Info switch functions - r -(SI) Layer 2 functions 1 I I L. Figure 7 (TIS 62-20). Type VI1 exchange connection.
19、Digital circuits with access to digital switched network s Handling and exchange control functions I Edition of January 15, 1989 = 2326434 O009077 2 I- 1 $2.5. $2.6. 52.7.3. $2.12. 53.5. 3.5. 3.6. 3.7. 3.8. 3.9. 3.10. TIS 62-20 E Page 5 Replace by the following: Services carried in a B channel requi
20、ring less than 64 kbit/s for a connection should be switched as 64 kbit/s connections. They should be presented to the exchange as 64 kbit/s channels by digital filling or by being multiplexed to a 64 kbit/s channel before entering the exchange. The process by which this is performed is not the subj
21、ect of this Recommendation. Lower bit rate channels multiplexed into a 64 kbit/s stream will be switched as a 64 kbit/s entity. Any additional services carried in the D-channel cannot be switched through the digital local exchange without special treatment and need further study. Delete any referenc
22、e to 24 x 64 kbit/s connections. Replace by the following: The exchange should have the capability of establishing semi-permanent connections, taking the following details into account: - semi-permanent connections are carried within PCM multiplexes together with other connections; - they are normal
23、ly not set up by subscriber control procedures; - they are normally not set up during the exchange busy hours; - they pass through the exchange switching network; - the grade of service for semi-permanent connections may differ from that of switched connections and Note. The supervision and re-estab
24、lishment (if provided) of semi-permanent connections in the event of a failure, require special arrangements in the exchange. require further study. Delete the bit pattern for 1544 kbit/s systems. Add the following sections. Signalling at interface V2 The signalling at interface V2 for system-depend
25、ent switching units is not the subject of CEPT Recommen- dations. Signalling at interface V3 For further study. Analogue environment On analogue subscriber lines, the digital local or combined exchange should be able to interwork with recommended CEPT signalling systems. Signalling to other exchange
26、s The exchanges should be able to interwork with other exchanges using the appropriate national and recommended CEPT signalling systems. Within the integrated digital network, the use of CCITT Signalling System No. 7 is preferred. Through-connection of signalling channels Signalling channels of 64 k
27、bit/s which enter the exchange via a multiplex structure may be connected through the exchange as semi-permanent connections. Signalling associated with semi-permanent connections Signalling associated with semi-permanent connections is the subject of further study. REFERENCES i CCT Recommendation 4.522. Digital exdiatige Connections, signalling mid ancillary fimtions. 2 T/S 60-00 Recommendation. Iiitrodiiction, field of application for digital local aiid combiFied, transit arid inter- national exchanges. Edition of January 15, 1989
