1、 TS22-03 Page 1 E Recommendation T/S 22-03 (by correspondence, May 1987) SUPPLEMENTARY SERVICE “CLOSED USER GROUP” Recommendation proposed by Working Group T/WG 1 1 “Signalling, Protocols and Switching” (SPS) Text of the Recommendation adopted by the “Telecomrnur-iicntiol2s” Comrnission : “The Europ
2、ean Conference of Postal and Telecommunications Administrations, considering - the common CEPT approach to the ISDN and general CEPT assumptions and policies for the evolution towards - the I. Series Recommendations of the CCITT, as well as other CCITT Recommendations on ISDN, to which - the need fo
3、r CEPT Administrations to have more precise answers to their specific European requirements, i.e. - the need for CEPT Administrations to have as a base a comprehensive set of Recommendations, in order to ISDN, CEPT Administrations have contributed most signicantly, to select and further define mater
4、ial from CCITT Recommendations, promote and strengthen European harmonisation, O recommends to the members of the CEPT, that the information flows, selection and location of network functions to support the supplementary service “Closed User Group” be in accordance with the guidelines and specificat
5、ions given in the attached text.” Edition of August 15, 1987 CEPT T/S*22-O3*E 87 2326434 0007848 b W TIS 22-03 E Page 2 1. 2. 2.1. 3. 4. 4.1. 4.1.1. 4.1.2. 4.2. 4.2.1. 4.2.2. DEFINITION The possibility for a group of users, connected to the ISDN, to inter-communicate only amongst themselves, and if
6、required, one or more users may be provided with incoming/outgoing access to users outside this group. PROSE DESCRIPTION The prose description considered is that provided in Recommendation T/SF 3 1-07 DYNAMIC DESCRIPTION The dynamic description is based on the prose description is provided in Annex
7、1. It consists of two SDL processes, one in relation to the calling party (A) and one in relation to the called party (B). FUNCTIONS AND INFORMATION FLOWS Identification of Elementary Functions Assumed network architecture The assumed network architecture is as in Figure 1 (T/S 22-03) (decentralised
8、 processing of CUG-informa- tion). The network architecture with centralised CUG management is for further study. Terminal Access providing Access providing Terminal A exchange A exchange B B Figure 1 (T/S 22-03). Assumed network architecture (decentralised processing of CUG information). Elementary
9、 jmctions Reference is made to the list of basic and additional elementary functions as contained in Recommendation T/N 03-01. In order to perform the supplementary service CUG, a number of actions need to be performed. These actions could be mapped to the elementary functions referred to above as f
10、ollows: 1. Check calling users access to CUG service: = B100, B105, B107. 2. Compatibility check with other supplementary services: = B110. 3. Identify the CUG used for the call: = B100, B107. Considerable call processing is involved in this to 4. Perform CUG checks associated with the calling user:
11、 = B100, B107. This function could be part of 5. Check called users access rights to the service: = B105, B107, B110. 6. Perform CUG checks associated with the called user: = B105, B107. This could be considered part of 7. Notify error conditions: = B105. Depending on how theuser (TE) is informed th
12、is could involve display, cater for the variations of CUG indexes, outgoing access, call barring, etc. 1 and 3 above. 5 above. annoucements functions. Information Fiow For the purposes of GAP phase 1 work, a decentralised implementation is assumed (see Figure 1 (T/S 22-03). Steps D, E and F of the C
13、CITT type method have been carried out. The attached information flow diagrams (Figure 2 (T/S 22-03) indicate the identified functions and information flows based on the overall service description given by the SDL diagrams. Details on information flow elements Note. The “information flow elements”
14、correspond to the service instructions outlined in Annex 1 to CEPT Recommen- dation T/S 21-01. i) From user to network Call demand (CUG fac. req., index, B-nr) = The CUG fac. req. and the CUG index could be additional information to a normal call set-up message. The index has local significance for
15、user A only and may be unspecified. Edition of August 15, 1987 TIS 22-03 E Page 3 B110 B309 Call rejected (cause) Call demand (CUG fac. req. index, B-nr)+ Successfull CUG call attempt. APEX B B100 B105 B107 B110 B309 A O9 - I APEX I Call demand (CUG fac. req. p/ index, B-nr)+ B100 B105 B107 CUG conn
16、ection demand (B-W, NI, IC) Unsuccessful CUG call attempt: call rejected at APEX A. Term A - Call demand (CUG fac. req. index, B-nr)+ L i) Call rejected (cause) - iv) APEX A - B100 B105 B107 B110 B309 A O9 A O9 - iii) CUG connection demand (B-W, NI, IC) iii) Connection rejected (cause) iv) APEX B A
17、O9 B105 B107 B110 I” I APEX B - A O9 A 09 - Call offer (CUG fac. req. index) 4 ii) Term B - - I Unsuccessful1 call attempt: call rejected at APEX B. Notes. 1) Each depicted terminal (Term) may be replaced by an ISPBX. 2) Transit Exchanges between the Access providing Exchanges (APEX) A and B have no
18、t been depicted. Such exchanges should handle the CUG connection demand as a normal connection demand and pass the CUG information transparently to the next exchange. + For non appearance of CUG fac. req. and/or index, see the service description and the details of CUG working in the draft SPS-PAR R
19、ecommendation on CUG. Figure 2 (T/S 22-03). Information flow for “Closed User Group” call. Term B - - Edition of August 15, 1987 CEPT T/S*22-03*E 87 = 2326414 0007850 4 TIS 22-03 E Page 4 ii) From network to user Call offer (CUG fac. req., index) = The CUG fac. req. and the CUG index could be additi
20、onal information to a normal call set-up message. The index has local significance for user B only and must be specified. iii) Within the network CUG connection demand (B-nr, network identification code, interlock code). The NIC and IC could be additional information to a normal initial address mess
21、age. iv) Causes applied at cail rejection: Rb Rf facility not provided Rn specified index not provided RO no index specified R10 incoming calls barred for called number R11 called subscriber no member of CUG Note. The use of the information flwo elements can be derived from the dynamic description p
22、rovided in Annex 1. outgoing calls barred within selected CUG -= Edition of August 15, 1987 Overall SDL-diagrams for “Closed User Group (7) Cause: = Rf Call type: TIS 22-03 E Page 5 Index: Call type: = normal = unspecified N Call Demand (CUG fac. req. index, B-nr) ENQUIRE Outgoing CUG arrangements (
23、A, call type, index) 4: CUG/OA call 1 I i I Note I - 1: CUG 2: Normal 3: Rejected call call (cause) 4 Note 1 I CUG conn. Call rejected (cause) Normal conn. demand to B CEPT T/S*22-03*E 7 232bYLY 0007852 W TIS 22-03 E Page 6 ENQUIRE Outgoing CUG arrangements (subs, call type, index) Speci- fied index
24、 provided Y Y within CUG with N Translate index into OUI, IC) I Preferential index provided Index = preferential index Iy N Translate index into NI, IC I NORMAL CALL I I Cause = Rb Cause = Ro Cause = Rn -1 1 0 CUG CALL CALL REJECTED 6 IC = Interlock Code NI = Network Identifier Rb = Outgoing calls B
25、arred within CUG Rn = No index specified Ro = Outgoing access not provided SDL-diagram 2: Macro definition ?Enquire outgoing CUG arrangements?. Edition of August 15, 1987 CEPT T/S*22-03*E 87 2326434 0007853 T - CUG connection demand N Cause = RI1 Call type: = CUG Y Call type: = normal I aN (NI, IC):
26、 = (0.0) rejected REJECTED cl Normal connection demand ENQUIRE Incoming CUG arrangements (B, call type, NI, IC) 3 Rejected 1 CUGcall 2 Normal call (cause) (index) I Call offer (CUG fac. req. index) Normal call offer TIS 22-03 E Page 7 Note 1. Other reasons may be present due to which the call will b
27、e rejected as may occur for normal call offering (e.g. no B-channel available). RI 1 = Called subscriber not member of CUG. SDL-diagram 3: Process in relation to subscriber B. Edition of August, 15 1987 I CEPT T/S*22-03*E 87 m 2326434 0007854 3 m TIS 22-03 E Page 8 ENQUIRE Incoming CUG arrangements
28、(subs., call type, NI, IC) Translate (NI, IC) into user CUG index I I N N c I I access pro- 1 Cause: Cause: = R11 = RIO 4 Y RIO= Incoming calls barred for called number. R11= Called subscriber not member of CUG. SDL-diagram 4 : Macro definition “Enquire incoming CUG arrangements”. I, Edition of August 15, ,di
