Content for  TS 22.173  Word version:  18.0.1

The reverse charging at communication set up time service allows the terminating party to be charged for the entire communication. Only usage based charges can be applied to the terminating party. The service shall be requested by the originating party at communication set up time. The terminating party must receive an explicit indication of a reverse charge communication request. This service description is based on the service description described in [E-19].

None.

The IMS Multimedia Telephony service shall support the interoperability of Reverse Charging with the PSTN/ISDN and vice versa.

The CUG service enables users to form groups of members, whose communication profile is restricted for incoming and outgoing communications. Members of a specific CUG can communicate among themselves but not, in general, with users outside the group. Specific CUG members can have additional capabilities that allow them to initiate outgoing communications to users outside the group, and/or to accept incoming communications from users outside the group. Specific CUG members can have additional restrictions that prevent outgoing communications to other members of the CUG, or prevent incoming communications from other members of the CUG. A closed user group consists of a number of members from one or more public, and/or private networks. Identification of each member shall be according to the requirements in [8]. A specific user may be a member of one or more CUGs. Subscription to a closed user group shall be defined for all communication services, or in relation to one, or to a list of communication services. This service description is based on the ISDN service description described in [E-22].

The IMS Multimedia Telephony service shall support the interoperability of the CUG service with the PSTN/ISDN and vice versa.No restrictions.

The 3PTY service enables a user to establish, participate in and control a simultaneous communication involving a number of users. The 3PTY service can be invoked by the served user who is involved in at least two calls (one active communication and at least one held communication), each of which may be an incoming or outgoing communication. The connections shall be established on each of the two communications prior to the invocation of the 3PTY service. 3PTY communication setup is equivalent to a three party conference created on request of the served user from existing communication sessions, this is equivalent to three party conference creation in CONF, For this reason 3PTY can be seen as a special case of CONF and most of service interactions for CONF apply also to 3PTY. This service description is based on the service description described in [E-21].

The IMS Multimedia Telephony service shall support the interoperability of the 3PTY service with PSTN/ISDN supplementary service 3PTY and vice-versa. The scope of this interworking may result in a limited service capability.

Flexible Alerting (FA) causes a call to a Pilot Identity to branch the call into several legs to alert several FA group members simultaneously or sequentially. In the simultaneous case, the first leg to be answered is connected to the calling party and the other call legs are abandoned. In the sequential case the order in which legs are alerted depends on application-specific criteria (including static preferences, last used device, last registered device). FA group members are alerted by dialling the public addressable identity (e.g. Public User Identity) associated with the FA group (i.e., a E.164 number or a SIP URI), which is referred to as the Pilot Identity. The Pilot Identity maps to a set of public addressable identities (e.g. PUI or GRUU) where each identity references a member of the FA group. The FA group consists of a list of identities, and can be configured by the user or the operator. In FA, there are two configuration options for busy indication: Single User Busy, and Multiple User Busy. The configuration of the option for a particular FA group shall be performed by the operator.

• For Single User Busy, the FA Group returns a busy indication if any group member indicates busy before the call is answered.
• For Multiple User Busy, the FA Group returns a busy indication if all accessible members indicate busy.

Personal Network Management (PNM) as specified in TS22.259 allows a user to manage her UEs in regard to terminating services according to preferences set by the user, capabilities and availabilities of devices.

Invocation of supplementary services for terminating services applicable to the active UE take precedence over invocation of supplementary service applicable to the called UE. There is no impact on specified interaction among supplementary services once invoked. There is no impact on the registration, erasure, activation, deactivation and interrogation of supplementary services.

The Customized Alerting Tone Service (CAT service) is an operator specific service by which an operator enables the subscriber to customize the alerting tone which is played to the calling party. The requirements for CAT within IMS shall be as described in [9].

The Customized Ringing Signal (CRS service) is an operator specific service by which an operator enables the subscriber to customize the ringing signal which is played to the called party. The requirements for CRS within IMS shall be as described in [10].

The CCNR service enables the originating party, encountering a terminating party who does not answer the communication (No Reply), to have the communication completed without having to make a new communication attempt when the terminating party becomes not busy after having initiated an activity. When the originating party requests the CCNR service, the network will monitor for the terminating party becoming not busy after having initiated an activity. When the terminating party becomes not busy after having initiated an activity, then the network will wait a short time in order to allow the resources to be re-used for originating a communication. If the resources are not re-used by the terminating party within this time, then the network will automatically recall the originating party. When the originating party accepts the CCNR recall, then the network will automatically generate a CCNR call to the terminating party. During CCNR recall, information shall be provided which indicates a CCNR recall. The information provided in the original communication attempt shall be included in the CCNR recall. This service description is based on the service description described in [E-23].

The IMS Multimedia Telephony service shall support the interoperability of the CCNR service with PSTN/ISDN Supplementary Service CCNR and vice versa. The scope of this interworking may result in a limited service capability.

The eCNAM service [15] provides the terminating party with the eCNAM identity data of the originating party. The eCNAM identity data consists of a name and metadata. This service is available to a user only after subscription. The eCNAM service informs and protects terminating users from fraud attempts (e.g., fraudulent robocalls) through its retrieval, assembly and delivery of the call metadata together with the results of the Caller Identity Analytics function (defined in Clause 3.1). The Caller Identity Analytics function is expected to encompass the results of verification, such as the Secure Telephone Identity Revisited (STIR) [16] / Signature-based Handling of Asserted information using toKENs (SHAKEN) [17]. The eCNAM service combines its metadata and the results of the Caller Identity Analytics function so that the end user receives an all-inclusive display of the pertinent call information. As a result, the end user receives the eCNAM metadata, authentication and verification mechanisms, and the outcome of the Caller Identity Analytics in the same eCNAM message.

The terminating service provider shall extract the originating party's telephone number from the originating party identity (e.g., from the tel-URI) to use in its query to retrieve eCNAM identity data from an authoritative data source. eCNAM identity data includes any information that allows the recipient to identify or contact the calling party, including the telephone number, name, logo. If the terminating service provider determines that the originating party's telephone number is verified and OIR is not invoked, the terminating service provider shall retrieve the originating party's eCNAM identity data. If the originating party's telephone number cannot be obtained, eCNAM identity data may not be available and the terminating service provider shall indicate the unavailability of the eCNAM identity data to the terminating party. If the originating party's telephone number cannot be verified, eCNAM identity data may not be displayed to the user. However, subject to service provider policy, the results of the Caller Identity Analytics function - if available - shall be included in the eCNAM message delivered to the UE. The interface between the terminating service provider (eCNAM service) and the Caller Identity Analytics function shall be private and secure. The terminating service provider shall obtain the eCNAM identity data from a trusted source. This trusted source may be the originating service provider or a third party with a business arrangement with the originating service provider. The interface between the terminating service provider and the trusted data source shall be private and secure. The conditions for exchange of data are governed by regional regulatory administration and through service provider agreement. The terminating service provider's delivery of originating party's eCNAM identity data to the terminating party shall be subject to Originating Identification Restrictions (OIR). If a terminating service provider requests a data element that the originating party did not consent to releasing, the data element shall not be returned. The service provider shall obtain its subscribers' consent for elements listed on the subscriber's communications service record at the start of communications service, and allow the subscriber to modify his/her consent at any point during the service. For the eCNAM service, the originating and terminating service providers shall agree on the retrievable metadata with the originating party's consent based on regional regulations. The eCNAM service shall support a service provider policy to establish the priority of delivering the identity data received from eCNAM query results and originating party identity data over any other data received from the originating party. 3GPP systems shall support the delivery of the eCNAM identity data in multiple languages (e.g., Chinese). Semantic translation is outside the scope of this standard. 3GPP systems shall relay the eCNAM identity data from the trusted sources to the terminating party without modification.

The IMS Multimedia Telephony service shall support the interoperability of the eCNAM service with mobile CS and PSTN/ISDN Supplementary Service CLIP. The eCNAM service shall utilize only the calling number originating from the PSTN to obtain the originating party's eCNAM identity data. eCNAM is not offered in the PSTN.