1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 1 TELECOMMUNICATION (03/93)STANDARDIZATION SECTOROF ITU$)4!,G0G035“3#2)“%2G0G03).!,).G0G03934%-G0G0.O G0G0 34!%G0G0 G0G0$%3#2)04)/.G0G0 national significant number is an ISDN number structured as specified inRecommendation E.164.A subscriber number is an
2、ISDN number structured as specified in Recommendation E.164.A default number is an agreed number between the user at the calling side and the network provider.A special arrangement is an arrangement between a customer and a public network operator whereby customersupplied calling numbers are not scr
3、eened by the public ISDN.CLIP Calling Line Identification PresentationCLIR Calling Line Identification Restriction2 Recommendation Q.951 (03/93)3.2.3 Qualification on the applicability to telecommunication servicesSee Recommendation I.251.3.3.2.4 State definitionsNo specific state definitions are re
4、quired.3.3 Operational requirements3.3.1 Provision/withdrawalSee Recommendation I.251.3.NOTE Annex A contains some additional procedures to support the two Calling party number information elementsdelivery option. This is a network option.3.3.2 Requirements on the originating network sideAll informa
5、tion pertaining to CLIP, shall be inserted in the SETUP message sent as part of the basic call proceduresaccording to 5/Q.931.In the case where no information is provided by the calling user (as part of the basic call procedures) the network shallprovide the default number associated with the user a
6、ccess (in which the call was generated) in the originating localexchange.When the calling party information is provided by the user, the network can only verify that the number is within therange allocated to that user.Where a special arrangement exists with the calling user, no screening of the cal
7、ling number they supplied, shall beperformed.3.3.3 Requirements in the networkThis subclause is not applicable to DSS 1.3.3.4 Requirements on the destination network sideSee 3.5.2.3.3.4 Coding requirementsAll information pertaining to CLIP is inserted in the SETUP message. 4.5.10/Q.931 and 4.5.11/Q.
8、931 give the codingfor the Calling party number and Calling party sub-address information elements which are required to support thisservice. The purpose of the Calling party number information element is to identify the origin of a call. The purpose ofthe Calling party sub-address information eleme
9、nt is to identify a sub-address associated with the origin of the call.3.5 Signalling requirements3.5.1 Activation/deactivation/registrationNot applicable.3.5.2 Invocation and operation3.5.2.1 Actions at the originating local exchange3.5.2.1.1 Normal operation3.5.2.1.1.1 Actions at the originating u
10、serThese procedures shall be provided as part of the basic service and the calling user need not have subscribed to the CLIPsupplementary service.Recommendation Q.951 (03/93) 3The numbering plan identification, to be indicated with the Calling party number information element, sent by the callinguse
11、r, shall be either “ISDN/telephony numbering plan” (see Recommendation E.164) or “unknown”.NOTE Either coding may be used and the treatment of both by the network is identical.Where the calling number included by the calling user is complete the type of number to be indicated within the Callingparty
12、 number information element, sent by the calling user, shall be one of the following:“Subscriber number” In the case where the complete subscriber number is sent.“National number” In the case where the complete national number is sent.“International number” In the case where the complete internation
13、al number is sent.Where a partial calling number is included by the calling user (e.g., to indicate digits specific to the Direct-Dialling-In orthe Multiple Subscriber Number supplementary services) the user shall set the type of number to be indicated within theCalling party number information elem
14、ent to “unknown”.3.5.2.1.1.2 Actions at the originating local exchange if a special arrangement does not applyThese procedures shall be provided as part of the basic service and the calling user need not have subscribed to the CLIPsupplementary service.When a SETUP message is received from the calli
15、ng user, the network shall check to see if the Calling party number andCalling party sub-address information elements are included.If the Calling party number information element is received with a coding of the numbering plan identification fieldother than “ISDN/telephony numbering plan” (see Recom
16、mendation E.164) or “unknown”, then the network shalldiscard the Calling party number information element and process the call as if that information was not received.The network shall set the value of the screening indicator based on the outcome of the screening of the calling number.The network sh
17、all disregard any value of the screening indicator, if received from the calling user.If the Calling party number information element is included, the network shall perform the screening function.NOTE 1 Some networks may accept a full ISDN number in a Calling party number information element with th
18、eaddition of a prefix or escape digits to the number digits field and the type of number field set to “unknown”.If the calling number received from the calling user is determined to be correct, the network shall set the screeningindicator to “user-provided, verified and passed”.If the screening func
19、tion fails the network shall note that the screening is failed and shall use a default number associatedwith the calling user. The network shall set the screening indicator to “network provided”.If the SETUP message does not contain the Calling party number information element the network shall use
20、a defaultnumber associated with the calling user. The network shall set the screening indicator to “network provided”.In the case where the calling user provides only partial calling number information and the number is a valid digitsequence for the user access arrangement, the network shall complet
21、e the number as appropriate. The network shall setthe screening indicator to “user-provided, verified and passed”.NOTE 2 In some cases the network cannot guarantee that the completed number identifies an end user.The information determined by the procedures above, shall be forwarded to the destinati
22、on local exchange, inassociation with the basic call request.The presentation indicator, as determined by the procedures of the CLIR supplementary service (see clause 4), shall beforwarded to the destination local exchange, in association with the basic call request.If the Calling party sub-address
23、information element is available, it shall be passed transparently through the network.The actions at the originating local exchange when special arrangement does not apply are summarized in Table 3-1.4 Recommendation Q.951 (03/93)TABLE 3-1/Q.951Information provided by the calling user and by the ne
24、tworkwhen special arrangement does not apply3.5.2.1.1.3 Actions at the originating local exchange if a special arrangement appliesThese procedures shall be provided as part of the basic service and the calling user need not have subscribed to the CLIPsupplementary service.When a SETUP message is rec
25、eived from the calling user, the network shall check to see if the Calling party number andCalling party sub-address information elements are included.If the Calling party number information element is received with a coding of the numbering plan identification fieldother than “ISDN/telephony number
26、ing plan” (see Recommendation E.164) or “unknown”, then the network shalldiscard the Calling party number information element and process the call as if that information element was notreceived.Information provided by the calling user Information provided by the network to the called userCalling num
27、berreceived from thecalling user (octet 4)Type of number(octet 3)Calling numberforwarded (if CLIR isnot activated) (octet 4)Screening indicatorforwarded (octet 3a)Type of numberforwarded (octet 3)No calling partynumber informationelement is provided bythe calling userDefault number storedat the netw
28、ork sidesufficient for returningthe callNetwork provided “International number”or “national number”(Notes 1, 7)Valid part of thenumber not sufficientfor returning the call(Note 2)“Unknown” Completion of thenumber(Note 3)User-provided verifiedand passed (Note 4)“International number”or “national numb
29、er”(Notes 1, 7)Correct completecalling party number(Note 5)“Subscriber number” or“national number” or“international number”Complete calling partynumberUser-provided verifiedand passed“International number”or “national number”(Notes 1, 7)Incorrect number(Note 6)Any type of number Default number store
30、dat the network sidesufficient for returningthe callNetwork-provided “International number”or “national number”(Notes 1, 7)NOTES1 A national number shall be converted to an international number at some point in the public network path where thedestination is in a different country.2 This assumes tha
31、t the users equipment provides that part of the number pertaining to its own (private) domain. This may bemultiple subscriber number digits provided by a terminal equipment or an extension line number provided by a private ISDN. Thenetwork shall interpret the number digits and check if it is a valid
32、 digit sequence according to the agreements existing between thecalling user and the network provider.3 Completion means that the remaining part of the ISDN number associated with the appropriate access is added to the userprovided part of the number.4 The term “verified” implies matching the user p
33、rovided number or part of this number with the range(s) of numbers stored atthe network side and it implies at least a valid format of user provided number information.5 The term “correct” implies, from the network point of view, matching the subscriber number provided by the user with one ofthe num
34、bers in the set of numbers stored at the network side.6 The number provided by the user is discarded.7 As a network option the type of number forwarded to the called user may be coded “unknown” when a prefix is added to thenumber, in which case the number is organized according to the network dialli
35、ng plan, i.e. prefixes or the absence of a prefix, shallbe used to distinguish international numbers and national numbers from each other.Recommendation Q.951 (03/93) 5If the Calling party number information element is received with the coding of the type of number field other than“national number”
36、or “international number”, then the network shall discard the Calling party number informationelement and process the call as if that information element was not received.The network shall disregard any value of the screening indicator, if received from the calling user.If the SETUP message does not
37、 contain the Calling party number information element the network shall use a defaultnumber associated with the calling user. The network shall set the screening indicator to “network provided”.If the Calling party number information element is included the network shall set the screening indicator
38、to “user-provided, not screened”.NOTE For the above condition, the procedures of basic call will provide for another calling number to be transportedthrough the network. This other calling number will contain the default number, with an associated screening indicator set to “networkprovided”.The inf
39、ormation determined by the procedures above, shall be forwarded to the destination local exchange, inassociation with the basic call request.The presentation indicator, as determined by the procedures of the CLIR supplementary service (see clause 4) shall beforwarded to the destination local exchang
40、e, in association with the basic call request.If the Calling party sub-address information element is available, it shall be passed transparently through the network.The actions at the originating local exchange when special arrangement applies are summarized in Table 3-2.TABLE 3-2/Q.951Information
41、provided by the calling user and by the networkwhen special arrangement applies3.5.2.1.2 Exceptional proceduresNot applicable.Information provided by the calling user Information provided by the network to the called userCalling party numberreceived from thecalling user (octet 4)Type of number(octet
42、 3)Calling party numberforwarded (if CLIR isnot activated) (octet 4)Screening indicatorforwarded (octet 3a)Type of numberforwarded (octet 3)No calling partynumber informationelement is provided bythe calling userDefault number storedat the network sidesufficient for returningthe callNetwork provided
43、 “International number”or “national number”(Notes 1, 2)Any digit sequenceconforming to E.164“National number” or“international number”Number provided bythe user (Note 1)User-provided, notscreened“International number”or “national number”(Notes 1, 2)NOTES1 A national number shall be converted to an i
44、nternational number at some point in the public network path where thedestination is in a different country.2 As a network option the type of number forwarded to the called user may be coded “unknown” when a prefix is added to thenumber, in which case the number is organized according to the network
45、 dialling plan, i.e. prefixes or the absence of prefixes, shallbe used to distinguish international numbers and national numbers from each other.6 Recommendation Q.951 (03/93)3.5.2.2 Actions at the transit exchangeThis subclause is not applicable to DSS 1.3.5.2.3 Actions at the destination local exc
46、hange3.5.2.3.1 Normal operationWhen the network sends a SETUP message to the called user and if the called user is provided with the CLIPsupplementary service, the network shall check to see if the calling number is available.If the calling number is available and presentation is allowed according t
47、o the presentation indicator supplied togetherwith the calling number, the network shall include the Calling party number information element in the SETUP messagesent to the called user. If provided, the network shall also include the Calling party sub-address information element inthe SETUP message
48、. The presentation and screening indicators associated with the calling number, and the calling sub-address, received at the destination exchange, shall be passed transparently to the called user.The numbering plan identification field shall be coded either “ISDN/telephony numbering plan” (seeRecomm
49、endation E.164)” or “unknown”.If presentation is not allowed according to the presentation indicator supplied together with the calling number, thenetwork shall include the Calling party number information element in the SETUP message sent to the called user. Thepresentation indicator in the Calling party number information element shall indicate “presentation restricted”. Thenetwork shall encode the screening indicator, numbering plan identification and the type of number according to one ofthe following options:i) The screening indicator shall indicate “n
