Content for  TS 22.173  Word version:  18.0.1

The Communication Waiting (CW) service enables a terminating party to be informed at the time that a new communication is requested, and that no resources are available for that incoming communication. The user has then the choice of accepting, rejecting or ignoring the incoming communication. The maximum number of communications that may be waiting is a service provider option. If the current number of communications waiting is equal to the maximum, then any new attempted incoming communication request shall be rejected with a busy cause. This service description is based on the service description described in [E-6] and [E-5]. As a service option, the communication waiting indication may also include the expiry time. As a service option, the user may be allowed to dynamically extend this timing. In the presence of another call at the destination user where the incoming call is identified as a callback to an emergency call, then either the communication request shall be presented, or the CW service shall be used.

No requirements.

The communication HOLD service enables a user to suspend media within a session, and resume that media at a later time. Each party in a communication can hold and retrieve the communication independently from the other party. This also applies when a communication involves more than two parties (e.g. CONF). This service description is based on the service description described in TS 22.228, dealing about the user ability to suspend and resume a session. The use of HOLD on an emergency call, or a call identified as a callback to an emergency call, by a user that is not the PSAP, shall be precluded.

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

The group of Communication Restriction Services includes two services:

• Outgoing Communications Barring (OCB).

This service allows a user to bar certain categories of outgoing communications. The network shall provide the capability for a user to select a set of categories (e.g. identities or range of identities) for barring. The type of barring is chosen by the user at provision time, and shall be valid for all outgoing communications. The network shall provide the capability for the user to bar outgoing communications based on user defined identities or identity ranges. Barring of an outgoing communication for a specific identity, a number of specific identities, or a range of identities shall be dependent on an entry in a OCB identity list held in the network. This list shall either be a "block list" or "allow list". A "block list" shall contain the identities or identity ranges to be barred by the network for outgoing communications. A "allow list" shall contain the identities or identity ranges that shall be allowed by the network for outgoing communications, i.e. all identities not in the "allow list" shall be barred. The ability of the served user to receive communications and to originate emergency communications shall be unaffected by OCB. This service description is based on the service description described in [E-15] and [E-16].

• Incoming Communications Barring (ICB).

This service allows a user to bar certain categories of incoming communications. The service also allows the user to have the barring of incoming communications activated always or only during certain conditions. The network shall provide the capability for a user to select from a set of categories (e.g. identities or range of identities) for barring. Barring of an incoming communication shall be dependent on an entry in an ICB identity list held in the network. This list shall be a "block list" which contains the identities or identity ranges to be barred by the network for incoming communications. The type of barring is chosen by the user at provision time and may be valid for all incoming communications, or be limited to a specific service group or certain conditions (e.g. when the user is roaming). The ability of the served user to set-up outgoing communications shall be unaffected by ICB. The ICB service includes a roaming condition. The roaming condition is set to true when the served user is roaming. The use of ICB on a call identified as a callback to an emergency call, by a user that is not the PSAP, shall be precluded.

• ICB enhancement of dynamic blocking of incoming communications

As a service option, the dynamic blocking of incoming communications service facilitates either or both of the following:

• A terminating users register of unwanted callers within the network for barring future incoming communications from the unwanted callers either permanently or for a temporary period or for a maximum lifetime which is set by the network operator. As an option, an additional "dynamic block list" may be provided, which is different compared to the standard ICB list. If this additional "dynamic block list" is provided, the user shall have the option to activate and deactivate that list independent of the already existing standard ICB list.
• A terminating user activates barring of spoofed calls either permanently or for a temporary period or for a maximum lifetime which is set by the network operator based on associated spoofed call detection applied to the session originator identity.

The following information shall be stored by the network for dynamic blocking of incoming calls:

• Actual Identity of caller: This is the network asserted identity of the caller.
• Start and end date for barring: This specifies the duration of block. If not provided, it implies the caller should be barred permanently or for a maximum lifetime which is set by the network operator.

Additionally, the following information may be provided by the user or spoofed call detection and associated with the actual identity:

• Reason: This specifies the reason for blocking or an alias, e.g. "Telemarketer". This field may assist the subscriber to manage their block list
• Published Identity of caller: This may be the actual identity of caller or 'private' or 'anonymous' if the caller has opted for privacy.

The network shall never reveal an identity withheld using privacy, OIR, or other mechanisms (i.e. list management must use the published identity). As an option and subject to the network operator policy, the network shall notify (e.g. announcement) the blocked originating user (unwanted user), that the called user has set an incoming communication barring for his identity. Subject to the network operator policy, the subscriber may request notification of communication barrings within the network in addition to subscribing to the dynamic blocking of incoming communications service.

The IMS Multimedia Telephony service shall support the interoperability of the CB service with mobile CS and PSTN/ISDN Supplementary Service CB and with ODB [6], and vice versa. The scope of this interworking may result in a limited service capability.

The CCBS service enables originating party, encountering a busy terminating party, to have the communication completed without having to make a new communication attempt when the terminating party becomes free. When originating party requests the CCBS service, the network will monitor for terminating party becoming free. When terminating party becomes free 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 terminating party within this time, then the network will automatically inform originating party that terminating party has become free. Originating party can generate the CCBS communication to terminating party. When originating party accepts the CCBS recall, then the network will automatically generate a CCBS communication to terminating party. During CCBS recall, information shall be provided which indicates a CCBS recall. The information provided in the original communication attempt shall be included in the CCBS recall. This service description is based on the service description described in [E-9]. As a service option, the time to expiry of the CCBS and the terminating party identity may be provided by the network, either at successful activation, or as a result of an interrogation.

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

The MWI service enables the network, upon the request of a controlling user to indicate to the receiving user, that there is at least one message waiting. The indication is sent to the receiving user when a message is deposited. Optionally, the network may send an indication to the user that there are no more unread message in the mail box. This indication may be send when the last unread message is read. The means by which the receiving user accesses and manages the mail box voice message service are outside the scope of the present document. This service description is based on the service description described in [E-13].

There is no interoperability with mobile CS and PSTN/ISDN because MWI is a local service.

The CONF service enables a user to participate in and control a simultaneous communication involving a number of users. When the CONF service is invoked, conference resources are allocated to the served user. Once a conference is active, users can join and leave a conference, and remote users can be added to or removed from the conference. This service description is based on the service description described in [E-7] and [E-8]. Conference participants can request to be informed of these actions. This information can include details beyond that described in [E-7] and [E-8], about other participants including their identity. The use of CONF on an emergency call, or a call identified as a callback to an emergency call, by a user that is not the PSAP, shall be precluded.

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

AOC is a group of services as follows:

• Advice Of Charge: charging information at communication Set-up time (AOC-S);
  The advice of charge at communication set-up service provides the user with information about the charging rates at the time of communication establishment or during the communication in the case of charging rates changes. The charge information provided relates to the charges incurred on the network to which the served user is attached.
  This service description is based on the service description described in [E-10] for AoC-S on a permanent mode.
• Advice Of Charge: charging information During the communication (AOC-D);
  The advice of charge during the communication service enables the user to receive information on the recorded charges for a communication during the active phase of the communication. The provided charging information may be exchanged between different operator domain if those operators have interconnect agreements to do so.
  This service description is based on the service description described in [E-11] for AoC-S on a permanent mode.
• Advice Of Charge: charging information at the End of the communication (AOC-E)
  The advice of charge at end of communication service provides the user with charging information for a communication when the communication is terminated. Dependent on the option chosen at the time of subscription, the information can be sent for all communications, or on a per communication basis. The charge information provided relates to the charges incurred on the network to which the served user is attached.
  This service description is based on the service description described in [E-12] for AoC-S on a permanent mode.

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

The Explicit Communication Transfer (ECT) service enables a party involved in a communication to transfer that communication to a third party. There are two situations in which transfer shall be possible:

• The transferring party has no ongoing communication with the transfer Target (ECT Blind/Assured) then either:
  1. the transferring party wants to perform the transfer without any further action on the transfer operation (ECT Blind),
  2. the transferring party wants to have the possibility to act on the transfer operation progress (ECT Assured).
• The transferring party has a communication with the transfer Target (ECT Consultative).

ECT Blind/Assured: The ECT Blind/Assured enables the transferring party A who has an active communication with a party B, which can be an incoming or outgoing communication, to transfer that communication into a new communication between party B and a third party C with out having prior communication with the third party C, and release it self from the communication. Because of the blind call towards party C, it is not possible to know in advance the result of the transfer. Therefore, party A should be informed of the establishment state of the transfer before being released from the communication. For Assured transfer, the transferring party A can limit the duration of the transfer attempt, release the transfer before it is completed or retrieve its communication with the transferee in case of transfer failure. ECT Consultative: The ECT Consulative enables a transferring party A to transform two of that party's communications (e.g. an active communication and a communication on hold, to parties B and C), each of which can be an incoming communication or an outgoing communication, into a new communication between party B and party C. Prior to transfer, the media session shall have been established on the communication between transferring party A and party B (transferee). On the communication between transferring party A and party C (transfer target), the media session shall have been established prior to transfer. The service should be applicable independent of whether party B and party C are IMS users or not. This service description is based on the service description described in [E-18]. The use of ECT on an emergency call, or a call identified as a callback to an emergency call, by a user that is not the PSAP, shall be precluded.

No restrictions.