1、 STD-ITU-T RECMN Q-BI-ENGL 1771 LI 48b2571 Db30272 OTT INTERNATIONAL TELECOMMUNICATION UNION CCITT THE INTERNATIONAL TELEGRAPH AND TELEPHONE CON SU LTATIVE COMMITTEE FUNCTIONS AND INFORMATION FLOWS FOR SERVICES IN THE ISDN Q.83 STAGE 2 DESCRIPTION FOR CALL COMPLETION SUPPLEMENTARY SERVICES SECTION I
2、 - CALL WAITING (CW) SECTION 4 - TERMINAL PORTABILITY Modifications and addenda to: Recommendation 0.83 STD-ITU-T RECMN Q-83-ENGL 1971 llb2591 Ob30273 T3b FOREWORD The CCITT (the International Telegraph and Telephone Consultative Committee) is a permanent organ of the International Telecommunication
3、 Union (ITU). CCITT 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 Plenary Assembly of CCITT which meets every four years, establishes the topics for study and approve
4、s Recommendations prepared by its Study Groups. The approval of Recommendations by the members of CCITT between Plenary Assemblies is covered by the procedure laid down in CCITT Resolution No. 2 (Melbourne, 1988). Recommendation 4.83, F, 1 and 4 was prepared by Study Group XI and was approved under
5、the Resolution No. 2 procedure on the 10th of September 1991. CCITT NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication Administration and a recognized private operating agency. O ITU 1991 All rights reserved. No part of this publ
6、ication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. Recommendation Q.83 STAGE 2 DESCRIPTION FOR CALL COMPLETION SUPPLEMENTARY SERVICES (revised 1991) 1 Call waiting (CW) 1.1 Sco
7、pe This Recommendation defines the stage 2 of the integrated services digital network (ISDN) as provided for the call waiting (CW) supplementary service. Stage 2 identifies the functional capabilities and the information flows needed to support the service description. The stage 2 description also i
8、dentifies user operations not directly associated with a call (see Rec. 1.130 i). This Recommendation is specified according to the methodology specified in Recommendation 4.65 2. This Recommendation does not formally describe the relationship between this supplementary service and the basic call bu
9、t, where possible, the information is included for guidance. In addition, this Recommendation does not speciQ the requirements where the service is provided to the user via a private ISDN. This Recommendation does not specify the requirements for the allocation of defined functional entities within
10、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 user via a telecommunications network that is not an ISDN. The CW supplementary service permits a
11、 subscriber to be notified of an incoming call (as per basic call procedures) with an indication that no interface information channel is available. The user then has the choice of accepting, rejecting or ignoring the waiting call (as per basic call procedures). The CW supplementary service is consi
12、dered meaningful when applied to the telephony teleservice and the speech and 3.1 kHz audio bearer services. Furthermore, it may also be meaningful when applied to other services. This Recommendation is applicable to the stage 3 Recommendations for the ISDN CW supplementary service. The term “stage
13、3“ is also defined in Recommendation I. 130 i. 1.2 References The references are cited at the appropriate places in the text and the publications are listed hereafter. Dated references, subsequent amendments to or revisions of any of these publications apply to this Recommendation only when incorpor
14、ated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. Dl CCITT Rec. 1.130 - Method for the characterization of telecommunication services supported by an ISDN and network capabilities of an ISDN, 1988. Pl CCITT Rec. 4.65 - Stage 2 of t
15、he method for the characterization of services supported by an ISDN, 1988. 131 CCITT Rec. 1.253.1 - Call Waiting (CW) supplementary service. 141 CCITT Rec. 1.112 - Vocabulary of terms for ISDNs, 1988. Recommendation 4.83 1 STD-ITU-T RECMN Q-83-ENGL 1771 qBb259L Ob30275 807 51 I 171 CCITT Rec. 4.83.2
16、 - Call Hold (CH) supplementary service. CCITT Rec. Q.71 - ISDN 64 kbith circuit mode switched bearer services, 1988. CCITT Rec. 1.210 - Principles of telecommunications services supported by an ISDN and the means used to describe them, 1988. Editors note - References 3 and 5 will become dated refer
17、ences to the next published versions of these Recommendations. The titles may need subsequent amendments. 1.3 Definitions For the purposes of this Recommendation, the following definitions apply: integrated services digital network (ISDN) See definition 308 of 0 2.3 of Recommendation I. 112 4. servi
18、ce: telecommunications service See definition 201 of 0 2.2 of Recommendation I. 112 4. supplementary service See 0 2.4 of Recommendation 1.210 7. subscriber B Subscriber B is the subscriber who is provided by the network with the CW supplementary service on a particular interface. user B User B is t
19、he one user who reacts to the call waiting at subscriber B. user C User C is the user who has originated a call to subscriber B which causes the CW supplementary service to be invoked. user A User A is a user who is engaged in a cai1 with user B (this call can be in any state). information channel c
20、ontrol A terminal that has information channel control, is active on a call, is alerting for an incoming call, has an outgoing call for which a channel has been selected, or has a call on hold with reservation. 1.4 Symbols and abbreviations cc Call control CCA Call control agent CW Call Waiting FE F
21、unctional entity FEA Functional entity action ISDN Integrated services digital network 2 Recommendation 4.83 LE Local exchange PNX Private network exchange SDL Specification and description language F E2 a FEI 1.5 Description Not applicable. FE3 1.6 1.6.1 Functional model description Derivation of t
22、he functional model The functional model for the CW supplementary service shall be as shown in Figure 1-114.83. - Ta rb FEI FE2 cc - CCA cc cc - r3 rl r2 - FE3 CCA - - 1.6.2 below: 1.6.3 Description of the functional entities The functional entities for the CW supplementary service above those of th
23、e basic call shall be as shown FE1 : FE2: waiting call control; FE3: waiting call agent. Relationship with a basic service The relationship of the functional model for the CW supplementary service with a basic call (from user C to waiting call notification receiver; user B) shall be as shown in Figu
24、re 1-2/Q.83. represents an outgoing call relationship from a CCA and rg represents an incoming call relationship to a CCA. Note - The basic call model is defined in 0 2.1 of Recommendation Q.71 6, with the exception that rl FIGURE 1-214.83 Relationship of functional model with a basic call 1.7 Infor
25、mation flow 1.7.1 Information flow diagrams Figures 1-3/Q.83 and 1-4/Q.83 show the information flows for a successful waiting call. Recommendation Q.83 3 SETUP req . RE PORT (ALERTINC ILeg. ind. - I REPORT (ALERTING) ( I - I REPORT (ALERTING) 93 1 - T112678C-90 FIGURE 1-3/Q.83 Notification of waitin
26、g call WAITING CALL ind. 1 FE1 t SETUP I - I FE3 932 933 Note SETUP T112679090 Note - Subscriber B may either clear the cail A-B using the basic call clearing procedures as described in Recommendation Q.71 6, or if the call hold supplementary service is subscribed, may hold the cail A-B using the pr
27、ocedures specified in 5. FIGURE 1-4/Q.83 Call waiting acceptance 4 Recommendation Q.83 1.7.2 Definition of individual information flows 1.7.2.1 Relationship r, 1.7.2.1.1 Contents of INFORM The contents of INFORM shall be as shown in Table 1-UQ.83. Name No information channel TABLE 1-1/Q.83 INFORM co
28、ntents Waiting call notification Optional (Note) Note - Mandatory if subscriber B subscribes to “calling user receives notification that his call is waiting”, otherwise not provided. Req. ind. Mandatory 1.7.2.2 Relationship rb 1.7.2.2.1 Contents of SETUP The contents of SETUP shall be as basic call
29、and additionally as shown in Table 1-2/Q.83. TABLE 1-2/Q.83 SETUP contents 1.7.2.2.2 Contents of CONNECTED The contents of CONNECTED shall be as basic call and additionally as shown in Table 1-314.83. Recommendation Q.83 5 TABLE 1-3lQ.83 Name Req. ind. Channel ID - channel number - exclusive; only t
30、he indicated channel is acceptable I I I Optional (Note) Note - 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. In this case, the terminal must connect to the last B-c
31、hannel indicated to the network. i. 8 SDL diagram for functional entities Q .-_I Timer Ir The final decision about the cause to be sent is made by basic call the calling user 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
32、2-9 (sheet 13 of 19) of Recommendation 4.71 6) within the action box “perform terminating screening”. The conditions for basic call to invoke CW are as defined in Recommendation 1.253.1 3. The exit CWO is the entry of a decision of whether supplementary services (other than the CW supplementary serv
33、ice) are provided. Note 2 - CW5 and CW6 break the basic call transition during the basic CC call slate 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 ofthe first REPORT (ALERTING) req.
34、 ind. Note 3 - CW7 and CW9 break the basic call transition during the basic CC call state 17 CALL 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 stale 27 r -r CALL SENT (ALERTING) (see Figure 2-9 (sheet
35、 16 of 19) of Recommendation Q.71 6) at receipt ofS!ETUP resp. conf pnor to sending SETUP resp. conf. on rz 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
36、 valid for a call that is not waiting with a non-acceptable SETUP resp. The cause is according to the unsuccessful case. (Such an exit, however, is not identified within Recommendation Q.71 6.) Nole 5 -The exit point to CW12 is within the same basic CC call state as for CW7, CW13: normally the expir
37、y of TCWZ shall lead to call clearing; at interaction with other supplementary services (e.g. Call Forwarding) other actions may be taken. FIGURE 1-6Q.83 (sheet 3 Of 3) CW - FE2 Recommendation Q.83 9 STD*ITU-T RECMN Q.83-ENGL 1991 W I86259L 0630283 985 f Insert CW indication into basic CCAs SETUP in
38、d. I Cause no circuit/ channel available f$ T1126840-90 FIGURE 1-7/Q.83 (sheet 1 of 2) CW - FE3 10 Recommendation Q .83 STD-ITU-T RECMN Q.83-ENGL 1771 48b2571 Ob30284 811 SETUP resp. received for a CW supplementary service is active - Accept -Allocate SETUP resp. no channel -1-1 ;IE2 CONNECTED req.
39、ind. with CHANNEL ID. 1 IL (Note 4) indicated B-channel to the waiting call Note I - CW15 and CW16 break the basic call transition during the basic call CCs FEA 251 (see Figure 2-8 (sheet 7 of 1 I) of Recommendation Q.71 6) by following the “Y branch of the decision “compatible” and prior to sending
40、 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 figure 2-8 (sheet 8 of i i) of Recommendation Q.71 6) at receipt of SETP resp. prior
41、 to sending SETUP resp. conf. Note 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 CONNECT. Note 4 - The channel identifica
42、tion is normally required. As a network option, the channel identification is not included if the user had responded with an exclusive channel identification. In this case, the terminal must connect to the last B-channel indicated to the network. FIGURE 1-7/Q.83 (sheet 2 of 2) CW - FE3 1.9 Functiona
43、l entity actions (FEAs) 1.9.1 FEAs of FE1 911: The functional entity shall receive the INFORM req. ind. (waiting call notification) and indicate this to the user. Recommendation Q.83 11 STDmITU-T RECMN Q*A3-ENGL 1771 48b2591 0b30285 758 W Scenario 1 1.9.2 FEAs of FE2 I TE I LE I TE I 920: The functi
44、onal entity shall: - recognize the CW supplementary service invoked from the basic service; Scenario 2 - check whether the number of waiting calls allows an additional waiting call. FE1 FEZ FE3 TE LE TE TE PNX TE 921: The functional entity shall formulate the Channel ID value “no information channel
45、” on receipt of the SETUP req. ind. 922: The functional entity shall: - check whether the option “information of the calling user about CW” is subscribed. If subscribed, it shall send INFORM (Waiting Call notification) req. ind.; - if the service provider option TCW2 is implemented it shall set TCW2
46、. 923: The functional entity shall allocate 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 as a network option. 1.9.3 FEAs of FE3 93 1 : The functional entity shall: - - for extend
47、ed B-channel selection: accept a call with ”no information 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 i
48、ndicated by the CONNECTED information flow to a call offered with “no information channel”. Note - 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. In this case, the te
49、rminal must connect to the last B-channel indicated to the network. 1.10 Allocation offunctional entities to physical locations The allocations of functional entities for the CW supplementary service are shown in Table 1-4/Q.83. TABLE 1-414.83 at opposite ends of the 12 Recommendation Q.83 4 Terminal portability 4.1 Scope This Recommendation defines the stage 2 of the integrated services digital network (ISDN) as provided by telecommunications operators for the Terminal Portability (TP) supplementary service. Stage 2
