3GPP TS V8.2.0 ( )

Transcription

1 TS V8.2.0 ( ) Technical Specification 3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; Communication Diversion (CDIV) using IP Multimedia (IM) Core Network (CN) subsystem; Protocol specification (Release 8) The present document has been developed within the 3 rd Generation Partnership Project ( TM ) and may be further elaborated for the purposes of. The present document has not been subject to any approval process by the Organizational Partners and shall not be implemented. This Specification is provided for future development work within only. The Organizational Partners accept no liability for any use of this Specification. Specifications and reports for implementation of the TM system should be obtained via the Organizational Partners' Publications Offices.

2 2 TS V8.2.0 ( ) Keywords CDIV, supplementary services, LTE Postal address support office address 650 Route des Lucioles - Sophia Antipolis Valbonne - FRANCE Tel.: Fax: Internet Copyright Notification No part may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all media. 2008, Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC). All rights reserved. UMTS is a Trade Mark of ETSI registered for the benefit of its members is a Trade Mark of ETSI registered for the benefit of its Members and of the Organizational Partners LTE is a Trade Mark of ETSI currently being registered for the benefit of its Members and of the Organizational Partners GSM and the GSM logo are registered and owned by the GSM Association

3 3 TS V8.2.0 ( ) Contents Foreword Scope References Definitions and abbreviations Definitions Abbreviations Communications Diversion (CDIV) Introduction Description General description Service description Communication Forwarding Unconditional (CFU) Communication Forwarding on Busy user (CFB) Communication Forwarding on no Reply (CFNR) Communication Forwarding on Subscriber Not Reachable (CFNRc) Communication Deflection (CD) Communication Forwarding on Not Logged-in (CFNL) Communication Diversion Notification (CDIVN) Operational requirements Provision/withdrawal Requirements on the originating network side Requirements in the network Coding requirements General SIP-Messages SIP messages for redirection SIP messages for CDIVN Parameters Signalling requirements General Activation/deactivation a Registration/erasure b Interrogation Invocation and operation Actions at the originating UA Void Void Void Void Actions at the AS of the diverting User General Checking of the diversion limits Setting of the diversion parameters by the AS Diversion procedures at the diverting AS Notification procedures of the originating user (Subscription Option) Indication of communication diversion to the diverting user /CDIV Notification (subscription option) Not reachable indication Actions at the AS of the diverted to user Void Void Void Void Void Void... 26

4 4 TS V8.2.0 ( ) Void Actions at the diverted to UA Actions at the diverting UA Interaction with other services Communication Hold (HOLD) Terminating Identification Presentation (TIP) Terminating Identification Restriction (TIR) Originating Identification Presentation (OIP) Originating Identification Restriction (OIR) Conference calling (CONF) Communication Diversion Services (CDIV) Malicious Communication Identification (MCID) Anonymous Communication Rejection and Communication Barring (ACR/CB) Explicit Communication Transfer (ECT) Actions at the diverting AS Determine whether ECT is applied to the diverted communication Handling of transfer requests Actions when CDIV is invoked again by the transferred communication Interworking with other networks Void Void Void Parameter values (timers) No reply timer CDIVN Buffer Timer CDIV Indication Timer Service Configuration for redirection services Structure of the XML Document General Communication Diversion Element Communication Diversion Rules Communication Diversion Rule Conditions Communication Diversion Rule Actions XML Schema Service Configuration of Communication Diversion Notification Structure of the XML Document Examples Communication Diversion Information General Communication Diversion Subscription Information Communication Diversion Notification Information XML Schema Annex A (informative): Signalling Flows...40 A.1 Normal cases...40 A.1.1 Communication Forwarding unconditional A.1.2 Communication Deflection A.1.3 Communication forwarding on no reply A.1.4 Communication Forwarding on Busy A.1.5 Communication Forwarding Not Logged-in (CFNL) A.1.6 Communication Diversion Notification (CDIVN) A.2 Interworking...54 A.2.1 Communication Forwarding unconditional A.2.2 Communication Deflection... 55

5 5 TS V8.2.0 ( ) Annex B (informative): Example of filter criteria...57 Annex C (informative): Coding considerations...58 Annex D (informative): Void...59 Annex E (informative): Change history...60

6 6 TS V8.2.0 ( ) Foreword This Technical Specification (TS) was been produced by ETSI Technical Committee Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN) and originally published as ETSI TS [19]. It was transferred to the 3rd Generation Partnership Project () in January The contents of the present document are subject to continuing work within the TSG and may change following formal TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an identifying change of release date and an increase in version number as follows: Version x.y.z where: x the first digit: 1 presented to TSG for information; 2 presented to TSG for approval; 3 or greater indicates TSG approved document under change control. y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections, updates, etc. z the third digit is incremented when editorial only changes have been incorporated in the document.

7 7 TS V8.2.0 ( ) 1 Scope The present document specifies the stage 3, Protocol Description of the Communications Diversion (CDIV) supplementary services, based on stage one and two of the ISDN Communication diversion supplementary services. It provides the protocol details in the IP Multimedia (IM) Core Network (CN) subsystem based on the Session Initiation Protocol (SIP) and the Session Description Protocol (SDP). In addition, the "Communication Diversion Notification" (CDIVN) CDIVservice is described in the present document. The present document is applicable to User Equipment (UE) and Application Servers (AS) which are intended to support the CDIV supplementary service. 2 References The following documents contain provisions which, through reference in this text, constitute provisions of the present document. References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific. For a specific reference, subsequent revisions do not apply. For a non-specific reference, the latest version applies. In the case of a reference to a document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document. [1] TS : " Multimedia Telephony Service and supplementary services". [2] TS : "IP Multimedia Call Control Protocol based on SIP and SDP". [3] IETF RFC 4244: "An Extension to the Session Initiation Protocol (SIP) for Request History Information". [4] TS : " Extensible Markup Language (XML) Configuration Access Protocol (XCAP) over the Ut interface for Manipulating Supplementary Services". [5] IETF RFC 4566: "SDP: Session Description Protocol". [6] IETF RFC 3261: "SIP: Session Initiation Protocol". [7] IETF RFC 3966: "The tel URI for Telephone Numbers". [8] IETF RFC 3325: "Private Extensions to the Session Initiation Protocol (SIP) for Asserted Identity within Trusted Networks". [9] TS : "Anonymous Communication Rejection (ACR) and Communication Barring (CB); Protocol specification". [10] Void. [11] TS : "Common Basic Communication procedures; Protocol specification". [12] TS : "Network Architecture". [13] ETSI ES : "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); Endorsement of the SIP-ISUP Interworking between the IP Multimedia (IM) Core Network (CN) subsystem and Circuit Switched (CS) networks [ TS (Release 7), modified]". [14] IETF RFC 4458: "Session Initiation Protocol (SIP) URIs for Applications such as Voic and Interactive Voice Response (IVR)". [15] IETF RFC 3265: "Session Initiation Protocol (SIP) -Specific Event Notification".

8 8 TS V8.2.0 ( ) [16] TS : "Explicit Communication Transfer (ECT); Protocol specification". [17] IETF RFC 3515: "The Session Initiation Protocol (SIP) Refer Method". [18] IETF RFC 4745: "Common Policy: A Document Format for Expressing Privacy Preferences". [19] ETSI TS V2.4.0: "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); PSTN/ISDN simulation services: Communication Diversion (CDIV); Protocol specification". [20] draft-ietf-sip-gruu-15 (October 2007): "Obtaining and Using Globally Routable User Agent (UA) URIs (GRUU) in the Session Initiation Protocol (SIP)". Editor's note: The above document cannot be formally referenced until it is published as an RFC. [21] OMA-TS-XDM-Core-V1_1: "XML Document Management (XDM) Specification", Version 1.1. [22] TS : "Session Initiation Protocol (SIP) based user configuration". [23] draft-saklikar-comm-diversion-notification-00 (September 2008): "A Session Initiation Protocol (SIP) Event Package for Communication Diversion Information". Editor's note: The above document cannot be formally referenced until it is published as an RFC. [24] IETF RFC 3326: "The Reason Header Field for the Session Initiation Protocol (SIP)". 3 Definitions and abbreviations 3.1 Definitions For the purposes of the present document, the terms and definitions given in TS [1] and the following apply: CDIV Session Identifier URI: URI created and inserted by a diverting AS that is routed through the same AS NOTE: This is used to solve the service interaction of CDIV and ECT. escaped character: See IETF RFC 3261 [6]. transferee: party being transferred to the transfer target transferor: party initiating the transfer transfer target: party that the existing communication is transferred to NOTE: After transfer the transferee and the transfer target are in communication with each other. 3.2 Abbreviations For the purposes of the present document, the following abbreviations apply: ACM ACR ANM AS CB CD CDIV CDIVN CFB CFNL CFNR Address Complete Message Anonymous Communication Rejection ANswer Message Application Server Communication Barring Communication Deflection Communication DIVersion Communication DIVersion Notification Communication Forwarding Busy Communication Forwarding on Not Logged-in Communication Forwarding No Reply

9 9 TS V8.2.0 ( ) CFNRc CFU CONF CPG CSCF ECT HOLD IAM IFC IMS IP ISDN ISUP MCID MGCF OCB OIP OIR P-CSCF PSTN RTP S-CSCF SDP SIP TIP TIR UA UE URI XCAP XML Communication Forwarding on subscriber Not Reachable Communication Forwarding Unconditional CONFerence Call ProGress message Call Session Control Function Explicit Communication Transfer communication HOLD Initial Address Message Initial Filter Criteria IP Multimedia Subsystem Internet Protocol Integrated Service Data Network Integrated Service digital network User Part Malicious Communication IDentification Media Gateway Control Function Outgoing Communication Barring Originating Identification Presentation Originating Identification Restriction Proxy-Call Session Control Function Public Switched Telephone Network Real-Time Transport Protocol Server-Call Session Control Function Session Description Protocol Session Initiation Protocol Terminating Identification Presentation Terminating Identification Restriction User Agent User Equipment Universal Resource Identifier XML Configuration Access Protocol extensible Markup Language 4 Communications Diversion (CDIV) 4.1 Introduction The Communications Diversion (CDIV) service enables diverting user, to divert the communications addressed to diverting user to another destination. 4.2 Description General description Service description The service description of the following CDIVs ervices CFU, CFB, CFNR and CD is based on the PSTN/ISDN supplementary services, whereas CFNL is a CDIV service based on requirements for IP based networks and CFNRc is based on requirements for mobile networks. In addition, CDIVN is a CDIVservice providing the user the capability to receive notifications about all diverted communications (CFU, CFB, CFNR, CD, CFNRc and CFNL). Generally the following requirements are expected to be fulfilled: - The service provides for the user or the network to identify an alternative destination for an IP multimedia session or individual media of an IP multimedia session. - The service provides for redirection to be initiated at various stages of an IP Multimedia session. For example:

10 10 TS V8.2.0 ( ) - Prior to the set up of an IP Multimedia session. - During the initial request for an IP Multimedia session (CFU). - During the establishment of an IP Multimedia session (CD). - The service provides redirection to be applied for all Multimedia sessions unconditionally or it can be caused by any of a set list of events or conditions. Typical causes could be: - Identity of the originating user. - Presence of the originating or destination party. - If the destination party is already in a session (CFB). - If the destination party is unreachable or unavailable in some other way (CFNL; CFNR, CFNRc). - If the destination party does not respond (CFNR). - After a specified alerting interval (CFNR). - User's preference on routing for specific IP Multimedia session based on the capabilities of multiple UEs sharing the same IMS service subscription. - The sending party, receiving party or the network on their behalf, may initiate redirection to alternative destinations. - The service provides for the user to subscribe to receive notifications of his/her communications diversions as dictated by the above requirements. The user will be further able to control: - If he/she wants to be notified of all or a particular subset of his/her Communication Diversions. - The amount of information he/she wishes to see as a part of the notifications of his/her CDIV services. - The time interval or availability instance when he/she wants to be notified of his/her Communication Diversions. The following services describe applications based on a subset of the above-mentioned requirements to provide user different possibilities to divert a communication. It should be possible that a user has the option to restrict receiving communications that are forwarded Communication Forwarding Unconditional (CFU) The CFU service enables a served user to have the network redirect to another user communications which are addressed to the served user's address. The CFU service may operate on all communications, or just those associated with specified services. The served user's ability to originate communications is unaffected by the CFU supplementary service. After the CFU service has been activated, communications are forwarded independent of the status of the served user. As a service provider option, a subscription option can be provided to enable the served user to receive a reminder indication that the CFU service has been activated. This indication is provided when the served user originates a communication and if the CFU service has been activated for the served user's address and for the service requested for the communication. The maximum number of diversions permitted for each communication is a service provider option. The service provider defines the upper limit of diversions. When counting the number of diversions, all types of diversion are included Communication Forwarding on Busy user (CFB) The CFB service enables a served user to have the network redirect to another user communications which are addressed to the served user's address and meet busy. The CFB service may operate on all communications, or just those associated with specified services. The served user's ability to originate communications is unaffected by the CFB supplementary service.

11 11 TS V8.2.0 ( ) As a service provider option, a subscription option can be provided to enable the served user to receive a reminder indication that the CFB service has been activated. This indication is provided when the served user originates a communication and if the CFB service has been activated for the served user's address and for the service requested for the communication. The maximum number of diversions permitted for each communication is a service provider option. The service provider defines the upper limit of diversions. When counting the number of diversions, all types of diversion are included. For more information on the procedures for determination of the busy condition see TS [11] Communication Forwarding on no Reply (CFNR) The CFNR service enables a served user to have the network redirect to another user communications which are addressed to the served user's address, and for which the connection is not established within a defined period of time. The CFNR service may operate on all communications, or just those associated with specified services. The served user's ability to originate communications is unaffected by the CFNR supplementary service. The CFNR service can only be invoked by the network after the communication has been offered to the served user and an indication that the called user is being informed of the communication has been received. As a service provider option, a subscription option can be provided to enable the served user to receive a reminder indication that the CFNR service has been activated. This indication is provided when the served user originates a communication and if the CFNR service has been activated for the served user's address and for the service requested for the communication. The maximum number of diversions permitted for each communication is a service provider option. The service provider defines the upper limit of diversions. When counting the number of diversions, all types of diversion are included Communication Forwarding on Subscriber Not Reachable (CFNRc) The CFNRc service enables a user to have the network redirect all incoming communications, when the user is not reachable (e.g. there is no IP connectivity to the user's terminal), to another user. The CFNRc service may operate on all communications, or just those associated with specified services. The user's ability to originate communications is unaffected by the CFNRc supplementary service. As a service provider option, a subscription option can be provided to enable the user to receive an indication that the CFNRc service has been activated. This indication is provided when the user originates a communication if the CFNRc service has been activated for the user and for the service requested for the communication. The maximum number of diversions permitted for each communication is a service provider option. The service provider defines the upper limit of diversions. When counting the number of diversions, all types of diversion are included Communication Deflection (CD) The CD service enables the served user to respond to an incoming communication by requesting redirection of that communication to another user. The CD service can only be invoked before the connection is established by the served user, i.e. in response to the offered communication (before ringing), i.e. CD Immediate, or during the period that the served user is being informed of the communication (during ringing). The served user's ability to originate communications is unaffected by the CD supplementary service. The maximum number of diversions permitted for each communication is a network provider option. The network provider defines the upper limit of diversions. When counting the number of diversions, all types of diversion are included Communication Forwarding on Not Logged-in (CFNL) The Communication Forwarding on Not Logged-in (CFNL) service enables a served user to redirect incoming communications which are addressed to the served user's address, to another user (forwarded-to address) in case the

12 12 TS V8.2.0 ( ) served user is not registered (logged-in). The CFNL service may operate on all communications, or just those associated with specified basic services. As a service provider option, a subscription option can be provided to enable the served user to receive a reminder indication that the CFNL service has been activated. This indication is provided when the served user logs out according to procedures described in IETF RFC 3261 [6]. The maximum number of diversions permitted for each communication is a service provider option. The service provider defines the upper limit of diversions. When counting the number of diversions, all types of diversion are included Communication Diversion Notification (CDIVN) The Communication Diversion Notification (CDIVN) service enables a served user to receive notification about the diversion of any of his/her incoming communications, which were addressed to the served user's address. As a service provider option, a subscription option can be provided to enable the served user to receive a reminder indication that the CDIVN service has been activated. This indication is provided when the served user originates a communication and if the CDIVN service has been activated for the served user's address. In case the user is not available to receive CDIVN (ex. user is logged out or not reachable) the Notification will be provided to the user following the user's registration, in case of CFNL when the user's CDIVN activation is still valid and if the time to buffer the Notification (CDIVN Buffer Timer) in the AS has not expired. NOTE: In case of CFNL and CRNRc, CDIVN activation continues to be valid after user registration in case the user uses the same user's address as before having that status of no connectivity and the time of SUBSCRIBE dialog has not expired in the AS. 4.3 Operational requirements Provision/withdrawal The CDIV services (Communication forwarding unconditional, Communication forwarding busy, Communication forwarding no reply, Communication forwarding not logged-in, Communication deflection and Communication Diversion Notification) is provided after prior arrangement with the service provider. The CDIV services are withdrawn at the served user's request or for administrative reasons. The CDIV supplementary services can be offered separately with subscription options. The notification service CDIVN is offered together with at least one CDIV supplementary service. For each subscription option, only one value can be selected. These subscription options are part of the call diversion profile for the served user. The subscription options are shown in table

13 13 TS V8.2.0 ( ) Served user receives indication that a communication has been forwarded (indication of communication diversion to the diverting user). Originating user receives notification that his communication has been diverted (forwarded or deflected). Table : Subscription options for CDIV services Subscription options Value Applicability No (default) CFU CFB Yes CFNR Served user allows the presentation of diverted to URI to originating user in diversion notification. Served user receives reminder indication on outgoing communication that CDIV is currently activated. Served user allows the presentation of his/her URI to diverted-to user. Served user allows the presentation of his/her URI to originating user in diversion notification. No Yes (default) No Not reveal as GRUU Yes (default) No (default) Yes No Not reveal as GRUU Yes (default) No Not reveal as GRUU Yes (default) CFNRc CFU CFB CFNR CFNRc CFNL CD CFU CFB CFNR CFNRc CFNL CD CFU CFB CFNR CFNRc CFNL CDIVN CFU CFB CFNR CFNRc CFNL CD CFU CFB CFNR CFNRc CFNL CD The following network provider options are available for the CDIV services:

14 14 TS V8.2.0 ( ) Table : Network provider options for CDIV services Network provider option Value Applicability Served user communication retention on invocation of diversion (forwarding or deflection). Retain communication to the served user until alerting begins at the diverted-to user Clear communication to the served user on invocation of call diversion CFNR CD Served user communication retention when diverting is rejected at diverted-to user. Total number of all diversions for each communication. Continue to alert the diverting user (see note 1) No action at the diverting user (see note 2) Maximum number of diverted connections ( upper limit is based on operator policy) CFNR CD CFU CFB CFNR CFNRc CFNL CD CDIV Indication Timer. Timer duration is a service provider option CFU CFB CFNR CFNRc CFNL CD Communication forwarding on no reply Timer default duration is a service provider option CFNR timer. (NOTE 3) CDIVN Buffer Timer; Timer Value for AS to store CDIVN, if it cannot be delivered Timer duration set by the service provider. Default value is 1 day CFNL, CFNRc in case of CDIVN as per CDIVN Configuration. NOTE 1: This applies to the retention of the communication at invocation of communication diverting. NOTE 2: This applies to the clearing communication option on invocation of communication diverting. NOTE 3: As a network provider option, it shall be possible to change the timer duration by the served user Requirements on the originating network side No specific requirements are needed in the network Requirements in the network No specific requirements are needed in the network. Based on the Initial Filter Criteria (IFC) Rules, indicating that the served user is subscribed to the CDIV supplementary services, the communication is be forwarded to an AS. NOTE: An example of the use of IFC is shown in annex B. 4.4 Coding requirements General TS [2] defines the messages and parameters for this supplementary service. The following messages and parameters are used to support the Communication diversion service due to fulfil the requirements SIP-Messages SIP messages for redirection Table shows the SIP messages that are used due to the coding rules in TS [2].

15 15 TS V8.2.0 ( ) Table : SIP Header information for redirection SIP Message Reference SIP Header INVITE [3] [8] [14] [20] 180 (Ringing) [3] [8] [14] [20] 181 (Call Is Being Forwarded) [3] [8] [14] [20] 200 (OK) response [3] [8] [14] [20] 302 (Moved Temporarily) [2] (see note) NOTE: History-Info header Privacy header cause-parameter in the uri-parameter "gr" parameter in the uri-parameter History-Info header Privacy header cause-parameter in the uri-parameter "gr" URI parameter in the Contact History-Info header Privacy header cause-parameter in the uri-parameter "gr" URI parameter in the Contact History-Info header Privacy header cause-parameter in the uri-parameter "gr" URI parameter in the Contact Contact header [14] The 302 (Moved Temporarily) response regarding the present document will be only used for the CD services. cause-parameter in the uri-parameter For more information on the cause-parameter is given in annex C. An AS that implements the CDIV service shall support the REFER method IETF RFC 3515 [17], to be able to handle the interaction with TS [16] SIP messages for CDIVN Table shows the SIP messages that are used for the CDIVN according to the coding rules in TS [2]. Table : SIP header information for notification (CDIVN) SIP Message Reerence SIP Header SUBSCRIBE [15] Event:comm-div-info NOTIFY [15] Event:comm-div-info NOTE: The event package with event name "comm-div-info" based on the SIP Event Notification framework is defined in draft-saklikar-comm-diversion-notification [23]. For more information on the message body associated with the event package "comm-div-info" refer to subclause Parameters The Privacy header is described in TS [2]. The present document refers for the History-Info header to IETF RFC 4244 [3], for the Privacy header and P-Asserted-Identity to IETF RFC 3325 [8], for GRUU to draft-ietf-sipgruu [20] and for the Cause-Code to IETF RFC 4458 [14]. 4.5 Signalling requirements General Configuration of supplementary services by the user should: - take place over the Ut interface using XCAP as enabling protocol as described in TS [4]; or - use SIP based user configuration as described in TS [22]; NOTE: Other possibilities for user configuration, such as web-based provisioning or pre-provisioning by the operator are outside the scope of the present document, but are not precluded.

16 16 TS V8.2.0 ( ) The enhancements to the XML schema for use over the Ut interface is described in subclause Activation/deactivation The services CFU, CFB, CFNR, CFNL, CFNRc and CD are individually activated at provisioning or at the subscriber s request. The services CFU, CFB, CFNR, CFNL, CFNRc and CD are individually deactivated at withdrawal or at the subscriber s request. For activation of the CDIVN, the message body within the SUBSCRIBE method would be used. Deactivation of CDIVN is either explicit by sending SUBSCRIBE message by the served user with "Expires" header set to "zero" or upon the expiration of the timer "Expire" in the AS. More details are described in subclause a Registration/erasure For registration of diversion information for the services CFU, CFB, CFNR, CFNL, CFNRc and CD, the mechanisms specified in subclause should be used. The diverted-to party address of the services CFU, CFB, CFNR, CFNL, CFNRc and CD can individually be registered at the subscriber s request by using the mechanisms specified in subclause For erasure of diversion information for the services CFU, CFB, CFNR, CFNL, CFNRc and CD, the mechanisms specified in subclause should be used. The diverted-to party address of the services CFU, CFB, CFNR, CFNL, CFNRc and CD can individually be erased at the subscribers request by using the mechanisms specified in subclause Registration/erasure is not applicable for CDIVN b Interrogation For interrogation of the services CFU, CFB, CFNR, CFNL, CFNRc and CD, the mechanisms specified in subclause should be used. Interrogation is not applicable for CDIVN Invocation and operation Actions at the originating UA A UE supporting CDIV services shall support origination of requests in the IM CN subsystem (as specified in TS [2]). When communication diversion has occurred on the served user side and the network option "Originating user receives notification that his communication has been diverted (forwarded or deflected)" is set to true, the originating UA may receive a 181 (Call Is Being Forwarded) response according to the procedures described in TS [2]. The Information given by the History-Info header could be displayed by the UA if it is a UE.

17 17 TS V8.2.0 ( ) Void Void Void Void Actions at the AS of the diverting User General If the session is subject to diversion the AS of the diverting user: - if modification of the To header is required as specified in the procedures of this subclause, shall operate as an AS providing 3 rd party call control, and specifically as a routeing B2BUA, as specified in subclause of TS [2]; - otherwise, shall operate as either an AS acting as a SIP proxy as specified in subclause of TS [2] or an AS providing 3rd party call control, and specifically as a routeing B2BUA, as specified in subclause of TS [2] NOTE: For the case when the session is not subject to diversion and CDIV, according the requirements in this document, is the only service being applied by the AS, then the AS only needs to act as a SIP proxy. If additional services are applied, then the AS might need to act as a routeing B2BUA Checking of the diversion limits When receiving an INVITE request and the AS determines that it must divert a communication: 1) the AS shall check if diverting the communication exceeds the number of diversions allowed within the network. The AS shall calculate the number of diversions using by the entries including a Cause parameter given by the History-Info header field, if the History-Info header field is present. If the number of diversions exceeds the given limit then the AS shall release the communication; and 2) if the communication has already undergone one or more diversion(s), the AS shall examine the entries in the Index entries parameter to see if another diversion is allowed due to network provider allowed limit of diversions. If the number of diversions exceeds the given limit then the AS shall send one of the following responses to the originating user: a) if communication diversion forwarding busy a 486 (Busy Here); b) if communication forwarding no reply, a 480 (Temporarily Unavailable); c) if communication forwarding unconditional a 480 (Temporarily Unavailable); or d) if communication deflection, a 480 (Temporarily Unavailable). NOTE: It is based on operator policy that the communication can be delivered to the latest diverting party when it is known. In all cases a Warning header field indicating that the communication is released due to the extension of diversion hops (e.g. "Too many diversions appeared") shall be sent Setting of the diversion parameters by the AS Overview After checking the limit of diversions the following sets the retargeted INVITE request according to the procedures in subclause

18 18 TS V8.2.0 ( ) First diversion; no History-Info header received When this is the first diversion the communication has undergone, the AS shall set the following information in the retargeted INVITE request: - the diverting parties address; - the diverted-to party address; - diversion information. The AS shall include or modify the following header fields with the specified values: a) The Request URI - set to the SIP URI or tel URI where the communication is to be diverted to (see <target> element in subclause ). b) The History-Info header field - two hist-info entries that shall be generated. 1) The first entry includes the hi-targeted-to-uri of the served user. The AS shall include the privacy header "history" within the hi-targeted-to-uri in the escaped form, if: - the served user wishes privacy (e.g. the served user is subscribed to the OIR Service); or - the served used has the subscription option "Served user allows the presentation of his/her URI to diverted-to user" set to false. Otherwise, if the first entry contains the "gr" parameter and the subscription option "Served user allows the presentation of his/her URI to diverted-to user" is set to "not-reveal-as-gruu", then the AS shall change the first entry as follows: - replace the first entry with the public user identity of the served user. The Index is set to index = 1 according to the rules specified in IETF RFC 4244 [3]. 2) The second entry includes the hi-targeted-to-uri of the address where the communication is diverted to. The AS shall set the cause param parameter (redirecting reason and redirecting indicator) included in the historyinfo header field according to the diversion conditions. The mapping between the diversion conditions and the coding of the cause param parameter is as follows: - if communication forwarding busy, the cause value "486" as defined by IETF RFC 4458 [14]; - if communication forwarding no reply, the cause value "408" as defined by IETF RFC 4458 [14]; - if communication forwarding unconditional, the cause value "302 as defined by IETF RFC 4458 [14]; - if communication deflection (Immediate Response), the cause value "480" as defined by IETF RFC 4458 [14]; - if communication forwarding not logged in, the cause value "404" as defined by IETF RFC 4458 [14]; - if communication deflection during alerting, the cause value "487" as defined by IETF RFC 4458 [14];and - if communication forwarding on subscriber not reachable, the cause value "503" as defined by IETF RFC 4458 [14]; according to the rules specified in IETF RFC 4244 [3]. The index is set to index = 1.1. c) The To header field: If the served user does not want to reveal its identity to the diverted-to party, then the AS shall change the To header field to the URI where the communication is diverted to. The served user does not want to reveal its identity when one of the following conditions holds true:

19 19 TS V8.2.0 ( ) - if the served user wishes privacy (e.g. the served user is subscribed to the OIR Service); or - if the served used has the subscription option "Served user allows the presentation of his/her URI to diverted-to user" set to "false". Otherwise, if the To header contains the "gr" parameter and the served user has the subscription option "Served user allows the presentation of his/her URI to diverted-to user" set to "not-reveal-as-gruu", then the AS shall change the To header field to a public user identity of the served user. In all other cases the AS shall not change the To header Subsequent diversion; a History-Info header received When this is the second or greater diversion the communication has undergone, the AS shall add a new history-info entry to the History-Info header field according to the rules defined in IETF RFC 4244 [3]. The following information is added to the retargeted request: - the diverted-to party address; - diversion information. The AS shall add or modify the following header fields with the specified values; a) Request URI - set to the SIP URI or tel URI where the communication is to be diverted to (see <target> element in subclause ). b) History-Info header The history entry representing the served user may be modified. One history entry is added. 1) The AS shall include the history entry representing the served user privacy header "history" in de escaped form within the hi-targeted-to-uri, if: - the served user wishes privacy (e.g. the served user is subscribed to the OIR Service); or - the served used has the subscription option "Served user allows the presentation of his/her URI to diverted-to user" set to false. If the history entry is already in the escaped form with the correct privacy value no modification is needed. If the history entry representing the served user contains the "gr" parameter and the subscription option "Served user allows the presentation of his/her URI to diverted-to user" set to "not-reveal-as-gruu", the AS shall change the history entry to a public user identity of the served user. In all other cases the AS shall not change history entry representing the served user. 2) A history entry is included where the hi-targeted-to-uri of the address where the communication is diverted to. shall be set to the SIP or TEL URI where the communication is diverted to cause param parameter (redirecting reason) included in the History-Info header field shall be set according to the diversion conditions. The mapping between the diversion conditions and the coding of the cause param parameter is as follows: - Communication forwarding busy, the Cause value "486" as defined by IETF RFC 4458 [14] shall be used. - Communication forwarding no reply, the Cause value "408" as defined by IETF RFC 4458 [14] shall be used. - Communication forwarding unconditional, the Cause value "302" as defined by IETF RFC 4458 [14] shall be used. - Communication deflection (Immediate response), the Cause value "480" as defined by IETF RFC 4458 [14] shall be used. - Communication Forwarding Not Logged in, The Cause value "404" as defined by IETF RFC 4458 [14] shall be used. - Communication deflection during alerting, the cause value "487" as defined by IETF RFC 4458 [14] shall be used.

20 20 TS V8.2.0 ( ) - Communication Forwarding on Subscriber Not reachable, the cause value "503" as defined by IETF RFC 4458 [14] shall be used. The Index shall be incremented according to the Basic Forwarding rules specified in subclause "Indexing in the History-Info Header" of IETF RFC 4244 [3] the new level index "1" shall be used. c) To header: If the served user does not want to reveal its identity to the diverted-to party, then the To header shall be changed to the URI where the communication is diverted to. The served user does not want to reveal its identity when one of the following conditions holds true: - if the served user wishes privacy (e.g. the served user is subscribed to the OIR Service); or - if the served used has the subscription option "Served user allows the presentation of his/her URI to diverted-to user" set to false. Otherwise, if the To header contains the "gr" parameter and the served user has the subscription option "Served user allows the presentation of his/her URI to diverted-to user" set to "not-reveal-as-gruu", then the To header shall be changed to a public user identity of the served user. In all other cases the To header shall not be changed Overview of the operation Figure shows the example of a communication path for multiple diversions. A B C D E F G HOP 1 HOP 2 HOP3 HOP 4 HOP 5 HOP 6 Figure : Originally A calls B Information transferred in the INVITE request Table shows which parameters and header fields that are modified in a diversion AS. Number Information P-asserted-Identity Request URI Hi-targeted-to-uri History Index added hi-targeted-to-uri Reason Privacy Table : Parameter information for multiple redirection HOP 1 HOP 2 HOP 3 HOP 4 HOP 5 HOP 6 A B A C B,C (1) and (2) B,C V (1), V (2) W (1), W (2) A D B,C,D (3) D (3) V (3) W (3) A E B,C,D,E (4) E (4) V (4) W (4) A F B,C,D,E,F (5) F (5) V (5) W (5) A G B,C,D,E,F,G (6) G (6) V (6) W (6) index 6 Hi-index index 1/index 2 index 3 index 4 index 5 V = Value regarding the rules the Reason header field (e.g. SIP cause or redirection cause). W = privacy value (header) or (none) or no entry. NOTE: The Hi-index field shall be increased by 1 due to the rules described in TS [4] Diversion procedures at the diverting AS The diverting AS shall continue the communication depending on the service that is causing the diversion: 1) Communication Forwarding Unconditional or Communication Forwarding Busy network determined user busy or Communication forwarding on Not Logged in The AS shall continue in the following manner:

21 21 TS V8.2.0 ( ) - If the notification procedure of the originating user is supported then the originating user shall be notified as described in the subclause An INVITE request containing the diverted-to URI shall sent to the (outgoing) S-CSCF. The INVITE request shall includes the parameter information as shown in table and described in subclause If the served user has subscribed to the indication of communication diversion to the diverting user and/or CDIVN service, then the served user will be indicated to/notified of the communication diversion as described in subclause If the user has activated both CFNL and CDIVN, and CFNL was invoked then the AS will store the CDIVN according to the CDIVN Buffer Timer for a default time of 1 day set by the service provider. The user has the option of overwriting this timer value in the SUBSCRIBE request to the maximum value of 1 day. See subclause for more details. 2) Communication Forwarding No Reply After receiving the first 180 (Ringing) response the no reply timer (definition see subclause 4.8) shall be started. If forking is provided by the S-CSCF a further received 180 (Ringing) response does not refresh the timer. When receiving any other final response the no reply timer shall be terminated. When the no reply timer defined in subclause 4.8 expires: - The dialog(s) to the diverting user shall be terminated e.g. by sending a CANCEL request or BYE request according to the rules and procedures in IETF RFC 3261 [6], including a Reason header field (see RFC 3326 [24]) with the protocol set to "SIP" and the cause set to "408". - If the notification procedure of the originating user is supported then the originating user shall be notified as described in the subclause An INVITE request is sent to the (outgoing) S-CSCF towards the diverted-to user. The INVITE request includes the parameter information as shown in table If the served user has subscribed to the indication of communication diversion to the diverting user and/or the CDIVN service, then the served user will be notified of the communication diversion as described in subclause ) Communication Forwarding No Reply (ringing continues) After receiving the first 180 (Ringing) response the no reply timer (definition see subclause 4.8) shall be started. If forking is provided by the S-CSCF a further received 180 (Ringing) response does not refresh the timer. When the diverted-to-user has accepted the communication request (with 200 (OK) response) then the originating user shall be notified as described in subclause An INVITE request is sent to the outgoing S-CSCF towards the diverted to user. The INVITE request includes the parameter information as shown in table If the served user has subscribed to the indication of communication diversion to the diverting user and/or the CDIVN service, then the served user will be notified of the communication diversion as described in subclause If diverting user accepts the communication after sending the INVITE request the communication path towards the diverted to user shall be released according to the rules and procedures in RFC 3261 [6]. 4) Communication Forwarding User Determined Busy The Communication Forwarding User Determined Busy is offered to the served user when the AS: - The received 486 (Busy Here) shall be acknowledged with a ACK request. - If the notification procedures of the originating user is supported then the originating user shall be notified as described in the subclause

22 22 TS V8.2.0 ( ) - An INVITE request containing the diverted-to URI is sent to the outgoing S-CSCF. The INVITE request includes the parameter information as shown in table If the served user has subscribed to the indication of communication diversion to the diverting user and/or the CDIVN service, then the served user will be notified of the communication diversion as described in subclause ) Communication Deflection immediate response The Communication Deflection immediate response is offered to the served user. A 302 (Moved Temporarily) response is received. If the notification procedures of the originating user is supported then the originating user shall be notified as described in subclause An INVITE request containing the diverted-to URI is sent to the outgoing S-CSCF. The INVITE request includes the parameter information as shown in table If the served user has subscribed to the indication of communication diversion to the diverting user and/or the CDIVN service, then the served user will be notified of the communication diversion as described in subclause ) Communication Deflection during alerting When Communication Deflection during alerting is invoked after the AS receives a 180 (Ringing) "Ringing" response. then: - A 302 (Moved Temporarily) response is received; and - if the notification procedures of the originating user is supported then the originating user shall be notified as described in subclause ; and - an INVITE request containing the URI received in the Contact header of the 302 (Moved Temporarily) response as the diverted-to URI shall be sent as specified in ES [13]. The diverted-to URI could be restricted by setting the privacy header for the entry of the diverted-to URI to "history"; and - the INVITE request shall include the parameter information as shown in table "Parameter information for multiple redirection". If the served user has subscribed to the indication of communication diversion to the diverting user and/or the CDIVN service, then the served user will be notified of the communication diversion as described in subclause ) Communication Forwarding on Subscriber Not Reachable When the AS receives a not reachable indication (see subclause ) on the INVITE request forwarded to the served user, then the following criteria shall apply before the Communication Forwarding on Subscriber Not Reachable procedure is executed: - the served user has an active forwarding rule containing not-reachable condition (see subclause 4.9); and - the served user is registered. The following steps shall be followed to perform Communication Forwarding on Subscriber Not Reachable: 1) If the notification procedures of the originating user is supported then the originating user shall be notified as described in the subclause ) An INVITE request with the Request-URI set to the diverted-to URI is sent to the outgoing S-CSCF. The INVITE request includes the parameter information as shown in table If the served user has subscribed to the indication of communication diversion to the diverting user and/or CDIVN service, then the served user will be indicated to/notified of the communication diversion as described in subclause If the user has activated both CFNRc and CDIVN, and CFNRc was invoked then the AS will store the CDIVN according to the CDIVN Buffer Timer for a default time of 1 day set by the service provider. The user has the option of