1、 ATIS-1000642.2014 Integrated Services Digital Network (ISDN) Call Deflection Supplementary Service AMERICAN NATIONAL STANDARD FOR TELECOMMUNICATIONS As a leading technology and solutions development organization, ATIS brings together the top global ICT companies to advance the industrys most-pressi
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11、-kHz audio; 64-kbit/s unrestricted digital information; multi-rate (n 64 kbit/s). 2 Normative References The following standards contain provisions which, through reference in this text, constitute provisions of this American National Standard. At the time of publication, the editions indicated were
12、 valid. All standards are subject to revision, and parties to agreements based on this American National Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. 1 ATIS-1000642.2014 ATIS-1000113.2005(R2010), Telecommunications Sign
13、aling system number 7 (SS7) Integrated services digital network (ISDN) user part1ATIS-1000607.2000(R2009), Telecommunications Integrated services digital network (ISDN) Layer 3 signaling specification for circuit-switched bearer service for digital subscriber signaling system no. 1 (DSS1)2ATIS-10006
14、10.1998(R2013), Telecommunications Digital subscriber signaling system no. 1 (DSS1) Generic procedures for the control of ISDN supplementary services3ATIS-1000620.1991(R2012), Telecommunications Integrated services digital network (ISDN) Circuit mode bearer service category description4ATIS-1000625.
15、1993(R2013), Telecommunications Integrated services digital network (ISDN) Calling line identification presentation and restriction supplementary services5ITU-T Recommendation Q.71, ISDN circuit mode switched bearer services6ITU-T Recommendation Q.932, Generic procedures for the control of ISDN supp
16、lementary services2ITU-T Recommendation Q.950, Digital subscriber signaling system no. 1 (DSS1) Supplementary services protocol, structure and general principles2ITU-T Recommendation Q.952, Stage 3 service description for call offering supplementary services Diversion supplementary services23 Defini
17、tions progress indicator information, if available; calling party number information, if available; called party number information; redirecting number information, if one redirecting number is available, or original redirecting number information, if two redirecting numbers are available; sequentia
18、l diversion information on the number of times the call has been sequentially diverted; calling party subaddress, if available; original redirecting subaddress, if available. 5 ATIS-1000642.2014 This retained information, as well as parameter values signaled in a deflection request, is used to initi
19、ate call setup towards the deflected-to user. Information on an offered call is retained by the network for as long as the call can be deflected. When a circuit-mode call is offered, the served user has the option of requesting the network to redirect the call to another user. If the served user cho
20、oses to deflect the call, the served user provides a deflected-to number in a deflection request to the network. The deflecting user may also include routing information that identifies an interexchange carrier or a network-specific facility to be used in setting up the call to the identified deflec
21、ted-to user. The deflecting user may include a presentation status in the deflection request to indicate whether the deflected-to user may receive the deflecting users number. This indication shall override any default subscriptions that are in place to present or restrict presentation of the deflec
22、ting users number to the deflected-to user. The deflecting user may also indicate whether the call is to be locally cleared or is to remain in the current state pending other actions; if this indication is absent, the call will remain in the current call state. The deflecting user may include other
23、information received when the call was offered, for example, useruser information. If the deflecting user is an NT2, the call may have been redirected within the NT2. In this case, the NT2 may also include a redirection counter and information about the last redirecting user in the deflection reques
24、t. If the deflecting user is subscribed to “Call Deflection After Answer”, the served user may choose to deflect the call after answering it. The deflecting user may include the same information in the deflection request as defined for deflection before answer. When the network receives the deflecti
25、on request, the network screens the request to determine if redirection can be invoked. If the network determines that the request is valid, the network will redirect the call using its retained call setup information and accepted parameter values signaled in the deflection request. If the deflectin
26、g user did not request call clearing, for deflections made before answer, with the deflection request, the call continues to be offered to the deflecting user until the network determines that the deflection attempt is successful; for call deflections made after answer, the call to the deflecting us
27、er remains in the established state until the network determines that the attempt is successful. The deflecting user may subscribe to the “Call Return” option of selecting a specific time period during which the deflected-to user must answer the call. If the deflected-to user does not answer the cal
28、l within the specified time period, either because the deflected call cannot be completed or because the deflected-to user did not answer the offered call, the deflection attempt is stopped and a failure indication is sent to the deflecting user. If the deflecting user requests call clearing when in
29、voking call deflection, the call return option will not apply to that deflection. If the Call Return option is not used and the deflecting user retained an association with the call, a deflection attempt is considered successful when the call has been answered by the deflected- to user identified in
30、 the request or has reached alerting or interworking. If the Call Return option value is set to “Yes, success = answer”, a deflection attempt is only considered successful when the call has been answered by the deflected-to user before the Call Return timer expires. If the Call Return option value i
31、s set to “Yes, success = interworking or answer”, a deflection attempt is considered successful if the call has encountered interworking or has been answered by the deflected-to user before the Call Return timer expires. If the deflection attempt is successful, the network sends an indication that t
32、he attempt has been successful and clears the call to the deflecting user. If the deflecting user had requested call clearing with the deflection request, the network will clear the call to the deflecting user at the same time that it redirects it to the deflected-to user. If call offering to the de
33、flecting user ended (e.g., upon expiry of call control timers) or the call is cleared by the deflecting user while a call is being redirected, the redirection attempt continues, 6 ATIS-1000642.2014 and if the Call Return timer had been started, it shall be canceled and the call shall continue to be
34、deflected as if Call Return had not applied. Regardless of the setting of the deflecting users Call Return option, if the deflected-to user answers the redirection call request, the deflected-to user and the calling user are connected. If multiple diversions occur, a limit on the number of allowed d
35、iversions for the call is needed to prevent infinite looping. The maximum number of diversions allowed for a call should not be greater than five. The network shall keep track of the number of diversions that have occurred and this number shall be updated for an instance of either ISDN Call Deflecti
36、on or Call Forwarding. 4.2.2.2.2 Deflected-to Users View The deflected-to user may be an ISDN or non-ISDN user. The non-ISDN user may receive no notification of deflection. If the deflected-to user is an ISDN user, the user may receive redirecting number information. If the deflecting users “Redirec
37、ting Number Information Delivery” is set to “Yes”, the network shall pass an indication that presentation of the redirecting number is allowed. If that subscription option is set to “No”, the network shall pass an indication that presentation of the redirecting number is not allowed. However, if the
38、 deflecting user had included an indication of the presentation status of the redirecting number for the deflected-to user in the deflection request, this indication shall override the presentation status of the “Redirecting Number Information Delivery” subscription option. If multiple diversions ha
39、d occurred, the deflected-to user may receive two redirecting numbers. If the first, last, or both redirections occurred as a result of call deflection requests, the deflected-to user will receive an indication that the reason for redirection is call deflection with the appropriate redirecting numbe
40、r. The deflected-to user may also receive subaddress information associated with the redirecting number. For multiple diversions, the deflected-to user may receive two redirecting subaddresses, one associated with the first redirection and one associated with the last redirection. 4.2.2.2.3 Calling
41、Users View The calling user may be an ISDN user or non-ISDN user. The calling user originates a call using the normal call setup procedures. Each time the calling users call is deflected, the calling user may experience additional call setup delay. The calling user may also experience an interruptio
42、n or change in the perceived audible ringing if it is provided by different locations. Where appropriate, the calling user should receive call progress information indicating actions at the deflected-to users interface (e.g., alerting, interworking, etc.). If the calling user is an ISDN user and the
43、 deflecting user has subscribed to “Calling user receives notification that call has been deflected, with deflected-to number”, the network sends an indication of diversion toward the calling user with the deflected-to number when a deflection request is accepted. If the deflecting user is subscribe
44、d to “Calling user receives notification that call has been deflected, without deflected-to number”, the network sends an indication of diversion toward the calling user without the deflected-to number. If the deflecting users “Calling user receives notification that call has been deflected” subscri
45、ption option is set to “No”, no indication of diversion is sent to the calling user. If the deflecting user clears or is cleared by the network after the deflection request has been invoked, the calling user should not receive an indication of this clearing; however, the calling user 7 ATIS-1000642.
46、2014 may receive call progress messages due to events at the deflected-to users interface (e.g., alerting, interworking, etc.) 4.2.3 Exceptional Procedures 4.2.3.1 Activation/deactivation None identified. 4.2.3.2 Invocation The call deflection request contains an invalid address for the deflected-to
47、 user (e.g., a special service number like 411 or 911, or a number not defined in the users dialing plan); The call deflection request does not contain the number of a deflected-to user; The requested deflection exceeds the limit on the number of allowed diversions for a call; There is a protocol er
48、ror in the call deflection request; The call deflection has been requested at an inappropriate point in the call; A previous call deflection request for the same call has been received and has not been concluded, either successfully or unsuccessfully. After receiving the indication of failure, the s
49、erved user may issue another deflection request if the deflecting user is still associated with the call. If the deflecting user is not still associated with the call, and the deflection request is invalid or the call cannot be completed to the deflected-to user for any other reason, the network will clear the call. If the network determines that the request is valid, the network attempts to redirect the call to the deflected-to party. If the deflecting user is still associated with the call and the network detects that
