ITU-T Q 735 3-1993 Stage 3 Description for Community of Interest Supplementary Services Using SS No 7 Clause 1 - Closed User Group (CUG) Clause 3 - Multilevel Precedence and Preemp 7 (.pdf

1、 ITU-T RECMN+Q-735 93 m 48b2591 0585247 042 m INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU SPECIFICATIONS OF SIGNALLING SYSTEM No. 7 Q.735 (03/93) STAGE 3 DESCRIPTION FOR COMMUNITY OF INTEREST SUPPLEMENTARY SERVICES USING SS No. 7 Clause 1 - Closed User

2、 Group (CUG) Clause 3 - Multilevel precedence and preemption ITU-T Recommendation Q.735 (Previously “CCITT Recommendation”) ITU-T RECMN*Q-735 93 = 4862593 0585248 T89 = FOREWORD The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the International Telecom- munication Uni

3、on. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, established the t

4、opics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. ITU-T.Recommendation Q.735, clauses 1 and 3, was prepared by the ITU-T Study Group XI (1988-1993) and was approved by the WTSC (Helsinki, March 1-12, 1993). NOTES 1 As a consequence of a reform p

5、rocess within the International Telecommunication Union (ITU), the CCIT ceased to exist as of 28 February 1993. In its place, the ITU Telecommunication Standardization Sector (ITU-T) was created as of 1 March 1993. Similarly, in this reform process, the CCIR and the IFRB have been replaced by the Ra

6、diocommunication Sector. In order not to delay publication of this Recommendation, no change has been made in the text to references containing the acronyms “CCITT, CCIR or IFRB” or their associated entities such as Plenary Assembly, Secretariat, etc. Future editions of this Recommendation will cont

7、ain the proper terminology related to the new ITU structure. 2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. O ITU 1994 All rights reserved. No part of this publication may be rep

8、roduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. ITU-T RECMN*d.735 93 4862591 0585247 715 W CONTENTS 1 Closed User Group (CUG) . 1.1 Definition 1.2 Description 1.3 Operational requirements 1.4

9、 Coding requirements . 1.5 Signalling requirements 1.6 Interactions with other supplementary services 1.7 Interaction with other networks 1.9 Parameter value (timers) . 1.10 Dynamic description (SDLs) Multilevel precedence and preemption (MLPP) 3.1 Definition 3.2 Description of MLPP service 3.4 Codi

10、ng requirements . 3.5 Signalling Requirements . 3.6 Interactions with other supplementary services 3.7 Interactions with other networks . 3.8 Signalling Flows . 3.9 Parameter Values-Timers . 3.10 Dynamic Description (SDLs) . Appendix I . 1.8 Signalling flows 3 3.3 Operational requirements Recommenda

11、tion Q.735 (03/93) Page 1 1 1 2 2 10 13 15 15 19 19 24 24 24 25 25 31 41 43 43 49 49 66 1 ITU-T RECMN*Q.735 93 48b259L 0585250 637 Recommendation Q.735 STAGE 3 DESCRIPTION FOR COMMUNITY OF INTEREST SUPPLEMENTARY SERVICES USING SS No. 7 (Helsinki, 1993) 1 Closed User Group (CUG) 1.1 Definition The su

12、pplementary service Closed User Group (CUG) enables users to form groups, to and from which access is restricted. A specific user may be a member of one or more CUGs. Members of a specific CUG can communicate among themselves but not with users outside the group. Specific CUG members can have additi

13、onal capabilities that allow them to originate calls outside the group, and/or to receive calls from outside the group. Specific CUG members can have additional restrictions that prevent them from originating calls to other members of the CUG, or from receiving calls from other members of the CUG. 1

14、.2 Description 1.2.1 General description A CUG is a group of users who may be members of one or several public networks; each ISDN member of a CUG is identified by an ISDN number. The Closed User Group (CUG) supplementary service enables a group of users to intercommunicate only among themselves or,

15、 as required, one or more users may be provided with incoming/outgoing access to users outside the group. The stage 1 definition of the CUG service is given in Recommendation 1.255. The stage 2 description including network functions are given in Recommendation Q.85.1, and the stage 3 DSS 1 descript

16、ion is given in Recommendation 4.955.1. This stage 3 description of the CUG uses the ISDN User Part protocol as defined in Recommendations 4.761-4.764 and 4.730. The realization of the CUG facilities is done by the provision of interlock codes and is based on various validation checks as defined in

17、Recommendation Q.85 at call Set-up, determining whether or not a requested call to or from a user having a CUG facility is allowed. In particular, a validation check is performed by verifying that both the calling and called parties belong to the CUG indicated by the interlock code. The data for eac

18、h CUG that a user belongs to can either be stored at the local exchange to which the user is connected (decentralized administration of CUG data), or at dedicated point(s) in the network (centralized administration of CUG data). In 1 52.1.1 i) the call Set-up procedure based on decentralized adminis

19、tration of CUG data is specified making use of the ISDN User Part as defined in Recommendations 4.761-764 and 4.766. In 1.5.2.1.1 ii) the call Set-up procedure based on centralized administration of CUG data is specified making use of the ISDN User Part as defined in Recommendations Q.761-764, Q.766

20、 and Q.767 and the Transaction Capabilities (TC) as defined in Recommendations 4.771-775. In 1 S.2.1.1 i) the application service element (ASE) on top of Transaction Capabilities for CUG validation check with centralized administration of CUG data is specified. 1.2.2 Specific terminology CUG: Closed

21、 User Group. Calling Party Number is the network (e.g. E. 164) number of the calling party. Called Party Number is the network (e.g. E.164) number of the called party. Recommendation Q.735 (03/93) 1 ITU-T RECMN*Q*735 93 V8b259L 0585253 573 CUG call indicator in IAM CUG without outgoing access CUG In

22、terlock Code is the code to uniquely identify a CUG inside the network. Action at the gateway exchange Release the call with cause #29 Called User Index is the local index at the called user to identify a particular CUG he belongs to. CMC: CUG Management Centre 1.2.3 Not applicable. 1.2.4 State defi

23、nitions No specific state definitions are required. Qualification on the applicability to telecommunication services CUG with outgoing access Non-CUG 1.3 Operational requirements 1.3.1 Provisiodwithdrawal See Recommendation 1.255.1. 1.3.2 Requirements on the originating network side Treat the call a

24、s an ordinary calla) Treat the call as an ordinary call Not applicable. 1.3.3 Requirements in the network No specific network requirement identified. 1.3.4 Not applicable. Requirements on the terminating network side 1.4 Coding requirements Clause 3/Q.763 gives the coding for the Closed User Group i

25、nterlock code and the Optional forward call indicator parameters which are required to support this service. See Tables 1-1 through 1-10, TABLE 1-1/Q.735 ) Discard the interlock code parameter and change the CUG call indicator of the optional forward call indicator to non-CUG call or discard the who

26、le parameter if appropriate. 2 Recommendation 4.735 (OY93) ITU-T RECMN*Q-735 93 = 4862593 0585252 40T TABLE 1-VQ.735 Handling of a CUG call at the destination exchange CUG with OA not with cause #87 Non-CUG call Non-CUG call IA Incoming access OA Outgoing access ICB Incoming calls barred Match calle

27、d No match NOTE - As OA attribute of the called user is of no concern at the destination exchange, CUG+OA class is equivalent to CUG, and CUG+IA class is equivalent to CUG+IA in this table. Subscription of preferential CUG by the called user is also of no concern in this table. The interlock code in

28、 the received IAM matches one of the CUGs to which the user belongs. The interlock code does not match any of the CUGs to which the called user belongs. . Recommendation Q.735 (03/93) 3 TABLE 1-3/Q.735 Validation check of CUG call concerning the calling user Indication from calling user CUG+OA(*2)(*

29、3) IC spec. CUG CUG call (*I) (*3) IC: spec. CUG Calling user class CUG+OA(*2)(*3) IC: spec. CUG CUG call (*i) (*3) IC: spec. CUG CUG without pref Return Error cause #50 CUG+OAE without pref. Return Error #50 CUG+OAi without pref. CUG with pref. CUG+OAE with pref. CUG+OAI with pref. No CUG OAE Outgo

30、ing CUG call with index CUG+OA call with index CUG call (*i) (*3) + IC: spec. CUG IC: spec. CUG CUG call (*i) (*3) CUG cai (*i) (*3) I CUG+OA (*2) (*3) IC: spec. CUG IC: spec. CUG CUG call (*i) (*3) IC: spec. CUG CUG+OA (* 1) (*2) (*3) IC: spec. CUG CUG+OA(*2)(*3) IC: spec. CUG CUG+OA (*2) (*3) (* 1

31、) IC: spec. CUG CUC call without index Return Error cause #62 Return Error cause #62 Non-CUG call CUG (*4) call IC: pref. CUG CUG (*4) IC: pref. CUG Return Error #50 CUG+OA call Non-CUG call without index Return Error cause Return Error cause #62 Non-CUG call Return Error -I- Non-CUG call Non-CUG ca

32、ll cause #62 Return Error cause CUG call #62 IC: pref. CUG (*4) Non-CUG call CUG call (*4) pref. CUG IC: pref. CUG Return Error #50 Non-CUG call OAI IC NOTE - As IA (incoming access) attribute of the calling user is of no concern for this validation check,CUG+OA/iA is equivalent to CUG+OA in this ta

33、ble. (*i) (*2) (*3) (*4) (*5) Outgoing access, implicit outgoing access for all calls. interlock code of the CUG selected. In case of OCB (outgoing calls barred) within the Error with cause #53. In case of OCB within the CUG, the call is interpreted as a non-CUG call. In case the specified index doe

34、s not match any of the registered indices, Return Error with cause MO. In the case of OCB within the CUG, this combination is not allowed. Both “Preferential CUG and “implicit” outgoing access options imply that no subscriber procedures are needed to invoke either options when placing a call. When a

35、 user subscribes to both options, the network does not know which option the user is invoking, if no additional procedures are used when placing the call. Then one of the following operations are recommended: a) b) if no information is given, the preferential CUG will be assumed; the network will ro

36、ute the call with preferential CUG with outgoing access. The call will therefore be connected if the called access is: - - - a non-CUG user. a member of preferential CUG; or a member of another CUG with incoming access; or 4 Recommendation Q.735 (OY93) ITU-T RECMNsQ.735 73 48b259L O585254 282 CUG ma

37、tch check Match CUG call ind. in IAM CUG CUG+IA No ICB ICB No ICB ICB CUG call Return Error CUG call Return Error Return Error witk cause #87 cause #55 cause #55 CUG with OA not allowed CUG with OA allowed Non-CUG TABLE 1 -4lQ.735 Validation check of CUG call concerning the called user Class of call

38、ed user No match Match No match Return Error with cause #87 Return Error cause #55 I CUG call Return Error with cause #87 Return Error with cause #87 Non-CUG call Non-CUG call Non-CUG call Non-CUG Match No match NOTES 1 equivalent to CUG and CUG+OA/IA class is equivalent to CUG+IA in this table. Sub

39、scription of preferential CUG by the called user is also of no concern in this table. The interlock code in the receive IAM matches one of the CUGs the called user belongs to. The interlock code does not match any of the CUGs the called user belongs to. As OA (outgoing access) attribute of the calle

40、d user is of no concern at the destination exchange, CUG+OA class is 2 The ASN.1 information for the centralized CUG service is contained in Appendix I. Recommendation Q.735 (0393) 5 ITU-T RECMN*Q.735 93 m 48b259L 0585255 119 W CUG Check 1 TABLE 1-YQ.735 Parameters of operations and outcomes CUG Che

41、ck 1 Timer = 5-10 sec UnsuccessfulCheck CailingUserIndex CUGCallIndicator 10.7 CallingPartyNumber Bearercapability HighLayerCompatibility Parameters with Return Result Class = 1 Opt/Man O M M M O Code = 00000001 Reference 10.1 10.2 10.3 10.9 10.10 CUGInterlockCode CUGCalllndicator O M 10.5 10.2 Link

42、ed Operations Not applicable NOTES 1 manner as the ISUP Calling party number in 3.WQ.763. The code of this parameter is “1000001 1”. 2 manner as the ISUP CUG interlock code in 3.13/Q.763. The code of this parameter is “1oO00101”. 3 from 4.5.VQ.931 to 4.5.29/Q.931. The code for this parameter is “100

43、01000”. CUGCheckl OPERATION PARAMETER SEQUENCE BearerCapability, CUGCalllndicator, Calling Party Number, CaliingUserlndex OPTIONAL, HighLayerCompatibility OPTIONAL CUGlnterlockCode OPTIONAL The CaliingPartyNumber (10.3) is the network (e.g. E.164) number of the calling party. It is expressed in the

44、same The CUGInterlockCode (10.5) is the code to uniquely identify a CUG inside the network. It is expressed in the same The Bearercapability (10.9) is expressed in the same manner as the Bearer capability information element (octets 3 in addition, there is a need for a CUG identification mechanism t

45、hat would be accepted by ail of the encompassed networks. One such mezhanism presently exists for CUGs spanning over data networks having X.121 as the numbering pian (see Recommendation X. 180, Administrative Arrangements for International Closed User Groups). An equivalent mechanism should be defin

46、ed for CUGs on networks using the E.164 numbering plan, or on networks which do not use the same numbering plan. 1.8 Signalling flows Figure 1-1 for the decentralized CUG service. FIgures 1-2 to 1-4 for the centralized CUG service. Recommendation 4.735 (-3) 15 ITU-T RECMN*Q.735 93 W 4862593 0585265

47、Oh8 CPG (alerting) 4 - Originating user 16 Originating =hange WUP * CII proceeding ( Alerting ”- setup Call proceeding I Disconnect 4 Release B Release complete )” IAM) Transit exchange Teminathmg exchange ACM CPG (alerting) I ANM I Teminating user 4 setup ACM Comect information a) Successful establ

48、ishment of a CU0 call IAM) b) Unsuccessful establishment of a CUG call OE Orignating exchange TE Transliexchange DE Destham exchange IAM Initial address message CPG Callpogress ANM Answermessage ACM Address complete mescage b, IAM contains the interlock code and CUG call indication, possibly with ou

49、tgoing access. ) REL contains the cause parameter to indicate why the call is being released. ( ) Indicates exchange functions. These are described below Figure 1-2. FIGURE 1-1/Q.735 Decentraiize operation of CUG Recommendation Q.735 (03/93) ITU-T RECMNaQ-735 93 4862573 05852bb TT4 Ongnatirig Ongnating Transit Transit Terminating user exchange CWA exchange exchange exchange Setup Call proceeding ( ( Alerting Cornet3 3) I CUG check 11 - tR check resuli IAM) ACM Network bounchry IAM) ACM I I CUG check 21, 4 RR check result I CPG(alel