1、INTERNATIONAL TELECOMMUNICATION UNIONCCITT Q.951THE INTERNATIONALTELEGRAPH AND TELEPHONECONSULTATIVE COMMITTEESTAGE 3 DESCRIPTION FOR SUPPLEMENTARYSERVICES USING DSS 1STAGE 3 DESCRIPTION FORNUMBER IDENTIFICATIONSUPPLEMENTARY SERVICES USING DSS 1SECTION 1 Direct-Dialling-In (DDI)SECTION 2 Multiple Su
2、bscriber Number (MSN)SECTION 8 Sub-addressing (SUB)Recommendation Q.951Geneva, 1992FOREWORDThe CCITT (the International Telegraph and Telephone Consultative Committee) is a permanent organ of theInternational Telecommunication Union (ITU). CCITT is responsible for studying technical, operating and t
3、ariffquestions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwidebasis.The Plenary Assembly of CCITT which meets every four years, establishes the topics for study and approvesRecommendations prepared by its Study Groups. The approval of Recommendation
4、s by the members of CCITT betweenPlenary Assemblies is covered by the procedure laid down in CCITT Resolution No. 2 (Melbourne, 1988).Recommendation Q.951, 1, 2, 8, was prepared by Study Group XI and was approved under theResolution No. 2 procedure on the 4th of February 1992._CCITT NOTEIn this Reco
5、mmendation, the expression “Administration” is used for conciseness to indicate both atelecommunication Administration and a recognized private operating agency. ITU 1992All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic ormechanica
6、l, including photocopying and microfilm, without permission in writing from the ITU.Recommendation Q.951 1Recommendation Q.951Recommendation Q.951STAGE 3 DESCRIPTION FOR NUMBER IDENTIFICATIONSUPPLEMENTARY SERVICES USING DSS 11 Direct-Dialling-In (DDI)1.1 DefinitionThis service enables a user to call
7、 directly to another user on an ISDN private branch exchange (ISPBX) orother private systems, without attendant intervention. This supplementary service is based on the use of the ISDNnumber and does not include Sub-addressing.1.2 Description1.2.1 General descriptionDDI numbers form part of the inte
8、rnational numbering plan according to Recommendation E.164.This Recommendation provides the flexibility to Administrations to use national numbering plans of fixed orvariable lengths. This flexibility also applies to DDI numbers, i.e. even within a given ISPBX or other private system,DDI numbers of
9、different lengths may appear.In networks with an open numbering plan, the length of the DDI number is not necessarily known by theservicing local exchange nor by any other entity of the public network.DDI is provided when at least a part of the ISDN number which is significant to the called user is
10、passed tothat user. These last digits (fixed or variable length) are sent from the exchange and received by the ISPBX or otherprivate system by en-bloc or overlap receiving, which finally and automatically establish a call to the destination withoutthe assistance of an operator. These last digits ar
11、e sent in accordance with Recommendation Q.931, 5.2.1.2.2 Specific terminologyThe DDI number is that part of the ISDN number which is significant to an ISPBX or other private system.1.2.3 Qualification of the applicability to telecommunication servicesNo restrictions.1.2.4 State definitionsThe state
12、s associated with basic call control according to Recommendation Q.931 are applicable.1.3 Operational requirements1.3.1 Provision/withdrawalThis service shall be provided after prior arrangement with the Administration and shall be withdrawn on thesubscribers request or for administrative reasons.2
13、Recommendation Q.9511.3.2 Requirements on the originating network sideThe basic call control procedures according to Recommendation Q.931, 5.1 are applicable.1.3.3 Requirements in the networkNot applicable to DSS 1 (digital subscriber Signalling System No. 1).1.3.4 Requirements on the terminating ne
14、twork sideWhen the DDI feature is provided to the called user, at least the DDI number shall be passed to the user in thecalled party number information element. The en-bloc or overlap receiving procedure is used to transfer the called partynumber information according to the rules specified in Reco
15、mmendation Q.931, 5.2.The destination network side may check the range and the format of the DDI number before it is passed to thecalled user.1.4 Coding requirementsThe DDI number is a part of the ISDN number which shall be inserted in the called party number informationelement coded as in Recommend
16、ation Q.931, 4.5.8.1.5 Signalling requirements1.5.1 Activation/deactivation/registrationNot applicable to DSS 1.1.5.2 Invocation and operation1.5.2.1 Normal operation1.5.2.1.1 Actions at the originating local exchangeNot applicable.1.5.2.1.2 Actions at the transit exchangeNot applicable to DSS 1.1.5
17、.2.1.3 Actions at the destination local exchangeThe DDI number is delivered from the network to the called user according to the procedures ofRecommendation Q.931, 5.2.The type of number is included in the called party number information element sent to the called user and shallbe coded as: unknown
18、(see Table 4-8/Q.931, Note 2 against “Type of Number”); or subscriber number, national number or international number (see Table 4-8/Q.931, Note 3 against “Typeof Number”).Note This coding is independent of the use of en-bloc procedures (where the called party number is sent in asingle message) or o
19、verlap procedures (where the called party number is sent in segments in several messages as itbecomes available).Recommendation Q.951 31.5.2.2 Exceptional proceduresNo exceptional procedures are required.1.6 Interactions with other supplementary services1.6.1 Call WaitingNo interaction.1.6.2 Call Tr
20、ansferNo applicable interaction at this time.1.6.3 Connected Line Identification PresentationNo interaction.1.6.4 Connected Line Identification RestrictionNo interaction.1.6.5 Calling Line Identification PresentationNo interaction.1.6.6 Calling Line Identification RestrictionNo interaction.1.6.7 Clo
21、sed User GroupNo interaction.1.6.8 Conference CallingNo applicable interaction at this time.1.6.9 Direct-Dialling-InNot relevant.1.6.10 Call Diversion (Call Forwarding) serviceNo applicable interaction at this time.1.6.10.1 Call Forwarding Busy1.6.10.2 Call Forwarding No Reply1.6.10.3 Call Forwardin
22、g Unconditional1.6.10.4 Call Deflection1.6.11 Line HuntingNo applicable interaction at this time.1.6.12 Three-Party ServiceNo applicable interaction at this time.1.6.13 User-to-User SignallingNo interaction.4 Recommendation Q.9511.6.13.1 Service 1No interaction.1.6.13.2 Service 2No interaction.1.6.1
23、3.3 Service 3No interaction.1.6.14 Multiple Subscriber numberIn some networks, subscription to the DDI and Multiple Subscriber Number supplementary service is mutuallyexclusive.1.6.15 Call HoldNo interaction.1.6.16 Advice of ChargeNo applicable interaction at this time.1.6.17 Sub-addressingNo intera
24、ction1.6.18 Terminal PortabilityNo interaction1.6.19 Call Completion Busy SubscriberNo interaction1.6.20 Malicious Call IDNo interaction1.7 Interactions with other networksNo special requirements for interactions with other networks are necessary.1.8 Signalling flowsNormal basic call control signall
25、ing flows according to Recommendation Q.931 are applicable.1.9 Parameter values (timers)The timers associated with basic call control according to Recommendation Q.931 are applicable.1.10 Dynamic description (SDLs)Recommendation Q.931 is applicable.Recommendation Q.951 52 multiple Subscriber Number
26、(MSN)2.1 DefinitionThe Multiple Subscriber Number (MSN) supplementary service provides the possibility for assigning multipleISDN numbers to a single public or private access. Note that this allows, e.g.,:1) a calling user to select, via the public network, one or multiple distinct terminals out of
27、a multiple choice(e.g. in a passive bus configuration);2) to identify the terminal to the network for the application of other supplementary services.It is considered: that in the case of a basic access, some service providers may not have knowledge or control over what isconnected, e.g. private ISD
28、N or a terminal configuration; that Administrations have differing numbering methods; that common international terminal specifications are desired.2.2 Description2.2.1 General descriptionThe stage 1 description, i.e. the MSN supplementary service description as seen from the user, can be found inRe
29、commendation I.251.2.The stage 2 description, i.e. the information flow for the MSN supplementary service, can be found inRecommendation Q.81, 2.This Recommendation specifies the stage 3 description, i.e. the protocol requirements for the MSNsupplementary service at the coincident S and T reference
30、point or at the T reference point (as defined inRecommendation I.411).The MSN supplementary service enables each individual terminal on one access to have one or moreidentities, by which one individual terminal (e.g. at a passive bus configuration) can be discriminated from the others.The Multiple S
31、ubscriber Number may be either: the whole ISDN number; or a part of the ISDN number (the least significant “n“ digit(s) where “n“ may be a number up to the fulllength of the ISDN number, and shall be a number large enough to allow all terminals on an access to beassigned an individual number); or as
32、 a service provider option, a number which can be mapped from the ISDN number by the network at thedestination network side.National or international prefixes cannot form part of the Multiple Subscriber Number.2.2.2 Specific terminologyThe served user for the MSN supplementary service is the called
33、user or another private installation on thedestination side of the network.The multiple subscriber number forms an end-to-end relationship but may have only local significancebetween the network and a specific terminal at the access.2.2.3 Qualification on the applicability to telecommunication servi
34、cesThe MSN supplementary service is applicable to all telecommunication services.6 Recommendation Q.9512.2.4 State definitionsThe states associated with basic call control according to Recommendation Q.931 apply.2.3 Operational requirements2.3.1 Provision and withdrawalThe service shall be provided
35、after prior arrangement with the service provider and shall be withdrawn on thesubscribers request or for administrative reasons. The service provider shall allocate a proper set of ISDN numberswhich shall meet the overall needs of the access concerned.2.3.2 Requirements on the originating network s
36、ideThe basic call control procedures according to Recommendation Q.931, 5.1 are applicable.If the access has the MSN supplementary service, the network may use (as a network option) the informationin the calling party number information element to identify the calling terminal, and if necessary, ass
37、ign the appropriatebasic or supplementary service profile.At the option of the service provider, one of the MSN numbers may be designated by the MSN subscriber asthe default number for the interface.2.3.3 Requirements in the networkThis section is not applicable to DSS 1 (digital subscriber Signalli
38、ng System No. 1).2.3.4 Requirements on the destination network sideWhen the Multiple Subscriber Number is provided to the called user, the network shall send the available partof the called party number or the relating digit(s) to the user en-bloc in the SETUP message according toRecommendation Q.93
39、1, 5.2.2.4 Coding requirementsThe Multiple Subscriber Number of the called user is coded in the called party number information element asspecified in Recommendation Q.931, 4.5.8.The Multiple Subscriber Number of the calling user is coded in the calling party number information elementas specified i
40、n Recommendation Q.931, 4.5.10.2.5 Signalling requirements2.5.1 Activation, deactivation and registrationNot applicable.2.5.2 Invocation and operation2.5.2.1 Normal operation2.5.2.1.1 Actions at the originating local exchangeThe Multiple Subscriber Number, if provided by the calling user, shall be d
41、elivered from the user to thenetwork according to the procedures of Recommendation Q.931, 5.1. The type of number indicated in the calling partynumber information element sent to the network shall be coded as: unknown (see Table 4-10/Q.931, Note 2 of type of number); or subscriber, national or inter
42、national number (see Table 4-10/Q.931, Note 3 of type of number).Recommendation Q.951 7The “numbering plan identification” field of the calling party number information element shall be codedeither “unknown” or “ISDN/telephony numbering plan (Recommendation E.164)”.If the user sends a multiple subsc
43、riber number, then the user shall supply sufficient digits to identify uniquelyone ISDN number from the set of ISDN numbers at that access.2.5.2.1.2 Actions at the transit exchangeThis section is not applicable to DSS 1.2.5.2.1.3 Actions at the destination local exchangeThe multiple subscriber numbe
44、r is delivered from the network to the user according to the procedures ofRecommendation Q.931, 5.2. The type of number indicated in the called party number information element sent to thenetwork shall be coded as: unknown (see Table 4-8/Q.931, Note 2 of type of number); or subscriber, national or i
45、nternational number (see Table 4-8/Q.931, Note 3 of type of number).The “numbering plan identification” field of the called party number information element shall be coded either“unknown” or “ISDN/telephony numbering plan (Recommendation E.164)”.2.5.2.2 Exceptional procedures2.5.2.2.1 Actions at the
46、 originating network sideIf a network receives fewer digits in the calling party number information element than is required to identifyuniquely one ISDN number from the set of ISDN numbers at that access, then the network shall discard this informationelement and shall behave as though the calling
47、party number information element had not been received.2.5.2.2.2 Actions at the destination user sideIf a user with the MSN supplementary service receives fewer digits in the called party number informationelement than it is programmed to require for terminal selection, then that user shall use the
48、available information in thatinformation element for its terminal selection procedure.If a terminal which has the MSN supplementary service receives a SETUP message without multiplesubscriber number digits, the terminal will handle the call according to Recommendation Q.931, 5.2.If a terminal which
49、does not support the MSN supplementary service receives a SETUP message with multiplesubscriber number digits, the terminal will handle the call according to Recommendation Q.931, 5.2.2.6 Interaction with other supplementary services2.6.1 Call WaitingNo interaction.2.6.2 Call TransferNo applicable interaction at this time.2.6.3 Connected Line Identification PresentationNo interaction.8 Recommendation Q.9512.6.4 Connected Line Identification RestrictionNo interaction.2.6.5 Calling Line Identification PresentationIf no calli
