ITU-T Q 83 1-1991 STAGE 2 DESCRIPTION FOR CALL COMPLETION SUPPLEMENTARY SERVICES SECTION 1 - CALL WAITING (CW) (Study Group XI)《呼叫完成补充业务第2阶段描述 呼叫等待(CW)》.pdf

1、INTERNATIONAL TELECOMMUNICATION UNION#)44 1 THE INTERNATIONALTELEGRAPH AND TELEPHONECONSULTATIVE COMMITTEEit does however define which functional entities may be allocated to a private ISDN.This Recommendation does not specify the additional requirements where the service is provided to the uservia

2、a telecommunications network that is not an ISDN.The CW supplementary service permits a subscriber to be notified of an incoming call (as per basic callprocedures) with an indication that no interface information channel is available. The user then has the choice ofaccepting, rejecting or ignoring t

3、he waiting call (as per basic call procedures).The CW supplementary service is considered meaningful when applied to the telephony teleservice and thespeech and 3.1 kHz audio bearer services. Furthermore, it may also be meaningful when applied to other services.This Recommendation is applicable to t

4、he stage 3 Recommendations for the ISDN CW supplementary service.The term “stage 3“ is also defined in Recommendation I.130 1.1.2 ReferencesThe references are cited at the appropriate places in the text and the publications are listed hereafter. Datedreferences, subsequent amendments to or revisions

5、 of any of these publications apply to this Recommendation onlywhen incorporated in it by amendment or revision. For undated references the latest edition of the publication referred toapplies.1 CCITT Rec. I.130 Method for the characterization of telecommunication services supported by an ISDN andne

6、twork capabilities of an ISDN, 1988.2 CCITT Rec. Q.65 Stage 2 of the method for the characterization of services supported by an ISDN, 1988.3 CCITT Rec. I.253.1 Call Waiting (CW) supplementary service.4 CCITT Rec. I.112 Vocabulary of terms for ISDNs, 1988.2 Recommendation Q.835 CCITT Rec. Q.83.2 Cal

7、l Hold (CH) supplementary service.6 CCITT Rec. Q.71 ISDN 64 kbit/s circuit mode switched bearer services, 1988.7 CCITT Rec. I.210 Principles of telecommunications services supported by an ISDN and the means used todescribe them, 1988.Editors note References 3 and 5 will become dated references to th

8、e next published versions of theseRecommendations. The titles may need subsequent amendments.1.3 DefinitionsFor the purposes of this Recommendation, the following definitions apply:integrated services digital network (ISDN)See definition 308 of 2.3 of Recommendation I.112 4.service: telecommunicatio

9、ns serviceSee definition 201 of 2.2 of Recommendation I.112 4.supplementary serviceSee 2.4 of Recommendation I.210 7.subscriber BSubscriber B is the subscriber who is provided by the network with the CW supplementary service on aparticular interface.user BUser B is the one user who reacts to the cal

10、l waiting at subscriber B.user CUser C is the user who has originated a call to subscriber B which causes the CW supplementary service to beinvoked.user AUser A is a user who is engaged in a call with user B (this call can be in any state).information channel controlA terminal that has information c

11、hannel control, is active on a call, is alerting for an incoming call, has anoutgoing call for which a channel has been selected, or has a call on hold with reservation.1.4 Symbols and abbreviationsCC Call controlCCA Call control agentCW Call WaitingFE Functional entityFEA Functional entity actionIS

12、DN Integrated services digital networkRecommendation Q.83 3LE Local exchangePNX Private network exchangeSDL Specification and description language1.5 DescriptionNot applicable.1.6 Derivation of the functional model1.6.1 Functional model descriptionThe functional model for the CW supplementary servic

13、e shall be as shown in Figure 1-1/Q.83.T1126760-90FE1 FE2 FE3rrabFIGURE 1-1/Q.83Functional model1.6.2 Description of the functional entitiesThe functional entities for the CW supplementary service above those of the basic call shall be as shownbelow:FE1:waiting call notification receiver;FE2:waiting

14、 call control;FE3:waiting call agent.1.6.3 Relationship with a basic serviceThe relationship of the functional model for the CW supplementary service with a basic call (from user C touser B) shall be as shown in Figure 1-2/Q.83.Note The basic call model is defined in 2.1 of Recommendation Q.71 6, wi

15、th the exception that r1represents an outgoing call relationship from a CCA and r3represents an incoming call relationship to a CCA.T1126770-90rarbr1r2r2r3FE1 FE2 FE3CCA CCACCCCCCFIGURE 1-2/Q.83Relationship of functional model with a basic call1.7 Information flow1.7.1 Information flow diagramsFigur

16、es 1-3/Q.83 and 1-4/Q.83 show the information flows for a successful waiting call.4 Recommendation Q.83T1126780-90911241241 251920921922924931FE1FE2 FE3rarbFIGURE 1-3/Q.83SETUPreq.REPORT(ALERTING)ind.SETUPreq. ind.INFORMreq. ind.SETUPreq. ind.REPORT(ALERTING)req. ind.REPORT(ALERTING)req. ind.WAITING

17、CALLind.Notification of waiting callT1126790-90FE1 FE2 FE3rarbFIGURE 1-4/Q.83SETUPconf.SETUPresp. conf.SETUPresp. conf.CONNECTEDreq. ind.SETUPresp.CONNECTEDind.NoteNote Subscriber B may either clear the call A-B using the basic call clearing procedures as described in Recommendation Q.71 6, or if th

18、e call hold supplementary service is subscribed, may hold the call A-B using the procedures specified in 5.Call waiting acceptance923932933Recommendation Q.83 51.7.2 Definition of individual information flows1.7.2.1 Relationship ra1.7.2.1.1 Contents of INFORMThe contents of INFORM shall be as shown

19、in Table 1-1/Q.83.TABLE 1-1/Q.83INFORM contentsNote Mandatory if subscriber B subscribes to “calling user receivesnotification that his call is waiting”, otherwise not provided.1.7.2.2 Relationship rb1.7.2.2.1 Contents of SETUPThe contents of SETUP shall be as basic call and additionally as shown in

20、 Table 1-2/Q.83.TABLE 1-2/Q.83SETUP contents1.7.2.2.2 Contents of CONNECTEDThe contents of CONNECTED shall be as basic call and additionally as shown in Table 1-3/Q.83.Name Req. ind.Waiting call notification Optional (Note)Name Req. ind.No information channel Mandatory6 Recommendation Q.83TABLE 1-3/

21、Q.83CONNECTED contentsNote The channel identification is normally required. As a networkoption, the channel identification is not included if the user hadresponded with an exclusive channel identification. In this case, theterminal must connect to the last B-channel indicated to the network.1.8 SDL

22、diagrams for functional entitiesT1126800-90CW1CW2911 raFE2FIGURE 1-5/Q.83CW FE1INFORMreq. ind.Insert contents ofINFORM into basiccall REPORT(ALERTING) ind.Note CW1 and CW2 break the basic call transition during the CCA-state“1 CALL SENT” after the receipt of REPORT req. ind. and prior to the output

23、REPORT ind.: see Figure 2-8 (sheet 2 of 11) of Recommendation Q.71 6.Name Req. ind.Channel ID channel number exclusive; only the indicated channel is acceptableOptional (Note)Recommendation Q.83 7T1126811-91CW3CW0920CW4CW5924922rFE1a3CW FE2Number of waitingcalls allows anadditional waitingcallCause

24、networkdetermineduser busyInsert noinformationchannel in basic callSETUP req. ind.921NoYesChannel negotiationas a network optionYesNoInform ofcall waiting?Subscription optionas a network provider optionINFORM req. ind.waiting callnotificationThis INFORM req. ind. shallbe sent simultaneously withthe

25、basic call REPORT(ALERTING) req. ind.TimerTCW2?YesNoSET (NOW +WAITING TIME,TIMER TCW2)TCW2, the “no answer timer” is a service provider option. TCW2 shall be automatically reset by basic call at any event which will result in clearing the call relation rFIGURE 1-6/Q.83 (sheet 1 of 3)CW68 Recommendat

26、ion Q.83T1126820-90CW7CW8CW9923CW FE2Select freeB-channel (usingreservationif available)Successful?Insert channelid. into basiccall connectedreq. ind.NoYesNote The channel identification is normally required. As a network option, the channel identification is not included if the user had responded w

27、ith an exclusive channel identification. In this case, the terminal must connect to the last B-channel indicated to the network.FIGURE 1-6/Q.83 (sheet 2 of 3)(Note)Recommendation Q.83 9T1126830-90CW12CW13TimerTCW2CAUSEUser alertingNo answerThe final decision aboutthe cause to be senttowards the call

28、ing useris made by basic call1 12CW FE2FIGURE 1-6/Q.83 (sheet 3 of 3)Note 1 CW3 and CW4 break the basic call transition during FEA 241 (see Figure 2-9 (sheet 7 of 19) and FEA 241A (see Figure 2-9 (sheet 13 of 19) of Recommendation Q.71 6) within the action box “perform terminating screening”. The co

29、nditions for basic call to invoke CW are as defined in Recommendation I.253.1 3. The exit CW0 is the entry of a decision of whether supplementary services (other than the CW supplementary service) are provided.Note 3 CW7 and CW9 break the basic call transition during the basic CC call state 17 CALL

30、SENT (see Figure 2-9 (sheet 8 of 19) of Recommendation Q.71 6), state 2 CALL SENT (see Figure 2-9 (sheet 15 of 19) of Recommendation Q.71 6) and state 27 r -r CALL SENT (ALERTING) (see Figure 2-9 (sheet 16 of 19) of Recommendation Q.71 6) at receipt of SETUP resp. conf. prior to sending SETUP resp.

31、conf. on r and prior to sending CONNECTED req. ind.Note 4 CW8 leads to the release of the call relation towards that specific user equipment. This would be the same procedural exit of basic call being valid for a call that is not waiting with a non-acceptable SETUP resp. The cause is according to th

32、e unsuccessful case. (Such an exit, however, is not identified within Recommendation Q.71 6.)Note 5 The exit point to CW12 is within the same basic CC call state as for CW7, CW13: normally the expiry of TCW2 shall lead to call clearing; at interaction with other supplementary services (e.g. Call For

33、warding) other actions may be taken.Note 2 CW5 and CW6 break the basic call transition during the basic CC call state 17 CALL SENT (see Figure 2-9 (sheet 7 of 19) of Recommendation Q.71 6) and state 2 CALL SENT (see Figure 2-9 (sheet 14 of 19) of Recommendation Q.71 6) at receipt of the first REPORT

34、 (ALERTING) req. ind.10 Recommendation Q.83T1126840-90CW15CW17 CW16931CW FE3Informationchannel control?Causeno circuit/channel availableInsert CWindication intobasic CCAsSETUP ind.FIGURE 1-7/Q.83 (sheet 1 of 2)YesNoRecommendation Q.83 11T1126850-90CW18CW19CW20CW21933bChannelIDr . FE2CONNECTED req. i

35、nd. with CHANNEL ID.(Note 4)AllocateindicatedB-channel tothe waiting callNote 3 CW20 and CW21 break the basic call transition during the basic CCA call state 10 AWAIT CONNECTED (see Figure 2-8 (sheet 8 of 11) of Recommendation Q.71 6) at receipt of CONNECTED req. ind. prior to the action box FEA 252

36、 CONNECT.FIGURE 1-7/Q.83 (sheet 2 of 2)CW FE3932 Accept SETUP resp. Allocate no channelSETUP resp. received for awaiting call and theCW supplementary serviceis activeNote 1 CW15 and CW16 break the basic call transition during the basic call CCs FEA 251 (see Figure 2-8 (sheet 7 of 11) of Recommendati

37、on Q.71 6) by following the “Y” branch of the decision “compatible” and prior to sending SETUP ind. and REPORT (alerting) req. ind. CW17 is the same exit as if the process attempt action failed.Note 2 CW18 and CW19 break the basic call transition during the basic CCA call state 4 INCOMING SETUP (see

38、 figure 2-8 (sheet 8 of 11) of Recommendation Q.71 6) at receipt of SETUP resp. prior to sending SETUP resp. conf.Note 4 The channel identification is normally required. As a network option, the channel identification is not included if the user had responded with an exclusive channel identification

39、. In this case, the terminal must connect to the last B-channel indicated to the network.1.9 Functional entity actions (FEAs)1.9.1 FEAs of FE1911: The functional entity shall receive the INFORM req. ind. (waiting call notification) and indicate thisto the user.12 Recommendation Q.831.9.2 FEAs of FE2

40、920: The functional entity shall: recognize the CW supplementary service invoked from the basic service; check whether the number of waiting calls allows an additional waiting call.921: The functional entity shall formulate the Channel ID value “no information channel” on receipt ofthe SETUP req. in

41、d.922: The functional entity shall: check whether the option “information of the calling user about CW” is subscribed. Ifsubscribed, it shall send INFORM (Waiting Call notification) req. ind.; if the service provider option TCW2 is implemented it shall set TCW2.923: The functional entity shall alloc

42、ate a B-channel to the waiting call on receipt of SETUP resp. conf.924: If the channel identification received from FE3 indicates “exclusive” the channel may be reserved asa network option.1.9.3 FEAs of FE3931: The functional entity shall: for extended B-channel selection: accept a call with “no inf

43、ormation channel indication”; indicate this waiting call to the user.932: The functional entity shall accept and transfer the users SETUP resp. towards CCA.933: The functional entity, for extended B-channel selection, shall allocate the B-channel indicated by theCONNECTED information flow to a call

44、offered with “no information channel”.Note The channel identification is normally required. As a network option, the channel identification is notincluded if the user had responded with an exclusive channel identification. In this case, the terminal must connect to thelast B-channel indicated to the

45、 network.1.10 Allocation of functional entities to physical locationsThe allocations of functional entities for the CW supplementary service are shown in Table 1-4/Q.83.TABLE 1-4/Q.83Note FE2 and FE3 are always allocated at opposite ends of thesame acces.FE1 FE2 FE3Scenario 1 TE LE TEScenario 2 TE P

46、NX TERecommendation Q.83 134 Terminal portability4.1 ScopeThis Recommendation defines the stage 2 of the integrated services digital network (ISDN) as provided bytelecommunications operators for the Terminal Portability (TP) supplementary service. Stage 2 identifies the functionalcapabilities and th

47、e information flows needed to support the service as description. The stage 2 description also identifiesuser operations not directly associated with a call (see Recommendation I.130 1).This Recommendation is specified according to the methodology specified in Recommendation Q.65 2.This Recommendati

48、on does not formally describe the relationship between this supplementary service and thebasic call but, where possible, this information is included for guidance.In addition, this Recommendation does not specify the requirements where the service is provided to the uservia a private ISDN. This Reco

49、mmendation does not specify the requirements for the allocation of defined functionalentities within a private ISDN; it does however, define which functional entities may be allocated to a private ISDN.This Recommendation does not specify the additional requirements where the service is provided to the uservia a telecommunications network that is not an ISDN.The TP supplementary service allows a user to move a terminal from one socket to another