10.15 Preconfigured regrouping

23.2803GPPCommon functional architecture to support mission critical servicesRelease 18Stage 2TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

10.15.1 General

The following subclauses specify the information flows and procedures for group and user regrouping using preconfigured groups for a single MC service, and which are utilised by the following MC services:

– MCVideo (as specified in 3GPP TS 23.281 [12])

– MCData (as specified in 3GPP TS 23.282 [13])

Editor’s note: Whether these procedures can be utilized by MCPTT is FFS.

MC service specific pre-requisites and resultant behaviour by functional entities in performing these procedures are specified in the respective MC service TSs as listed above.

Editor’s note: Whether these procedures impact the common functional architecture is FFS.

10.15.2 Information flows for preconfigured regrouping

10.15.2.1 Preconfigured regroup request (MC service client – MC service server)

Table 10.15.2.1-1 describes the information flow preconfigured regroup request from the MC service client to the MC service server.

Table 10.15.2.1-1 Preconfigured regroup request information elements

Information Element	Status	Description
MC service ID	M	The MC service ID of the requester
MC service group ID	M	MC service group ID of the regroup group
MC service group ID	M	MC service group ID of the MC service group from which configuration is to be taken
MC service group ID list	O (see NOTE)	List of MC service groups to be regrouped into the group regroup group
MC service user ID list	O (see NOTE)	List of MC service users to be regrouped into the user regroup group
NOTE: One and only one of these shall be present.

10.15.2.2 Preconfigured regroup request (MC service server – MC service client)

Table 10.15.2.2-1 describes the information flow preconfigured regroup request from the MC service server to the MC service client.

Table 10.15.2.2-1 Preconfigured regroup request information elements

Information Element	Status	Description
MC service ID	M	The MC service ID of the target MC service group member
MC service group ID	M	MC service group ID of the regroup group
MC service group ID	M	MC service group ID of the MC service group from which configuration is to be taken
MC service group ID list	O (see NOTE)	List of MC service groups to be regrouped into the group regroup group
MC service user ID list	O (see NOTE)	List of MC service users to be regrouped into the user regroup group
NOTE: One and only one of these shall be present.

10.15.2.3 Preconfigured regroup request (MC service server – MC service server)

Table 10.15.2.3-1 describes the information flow preconfigured regroup request from the MC service server to the MC service server.

Table 10.15.2.3-1 Preconfigured regroup request information elements

Information Element	Status	Description
MC service ID	M	The MC service ID of the requester
MC service group ID	M	MC service group ID of the regroup group
MC service group ID	M	MC service group ID of the MC service group from which configuration is to be taken
MC service group ID list	O (see NOTE)	List of MC service groups to be regrouped into the group regroup group
MC service user ID list	O (see NOTE)	List of MC service users to be regrouped into the user regroup group
NOTE: One and only one of these shall be present.

10.15.2.4 Preconfigured regroup response (MC service client – MC service server)

Table 10.15.2.4-1 describes the information flow preconfigured regroup response from the MC service client to the MC service server.

Table 10.15.2.4-1 Preconfigured regroup response information elements

Information Element	Status	Description
MC service ID	M	The MC service ID of the responding MC service client
MC service group ID	M	MC service group ID of the regroup group
Result	M	Result of the regrouping operation

10.15.2.5 Preconfigured regroup response (MC service server – MC service client)

Table 10.15.2.5-1 describes the information flow preconfigured regroup response from the MC service server to the MC service client.

Table 10.15.2.5-1 Preconfigured regroup response information elements

Information Element	Status	Description
MC service ID	M	The MC service ID of the requester of the regrouping operation
MC service group ID	M	MC service group ID of the regroup group
Result	M	Result of the regrouping operation

10.15.2.6 Preconfigured regroup response (MC service server – MC service server)

Table 10.15.2.6-1 describes the information flow preconfigured regroup response from the MC service server to the MC service server.

Table 10.15.2.6-1 Preconfigured regroup response information elements

Information Element	Status	Description
MC service ID	M	The MC service ID of the responding MC service client
MC service group ID	M	MC service group ID of the regroup group
Result	M	Result of the regrouping operation

10.15.2.7 Preconfigured regroup cancel request (MC service client – MC service server)

Table 10.15.2.7-1 describes the information flow preconfigured regroup cancel request from the MC service client to the MC service server.

Table 10.15.2.7-1 Preconfigured regroup cancel request information elements

Information Element	Status	Description
MC service ID	M	The MC service ID of the requester
MC service group ID	M	MC service group ID of the regroup group

10.15.2.8 Preconfigured regroup cancel request (MC service server – MC service client)

Table 10.15.2.8-1 describes the information flow preconfigured regroup cancel request from the MC service server to the MC service client.

Table 10.15.2.8-1 Preconfigured regroup cancel request information elements

Information Element	Status	Description
MC service ID	M	The MC service ID of the target MC service user or MC service group member
MC service group ID	M	MC service group ID of the regroup group

10.15.2.9 Preconfigured regroup cancel request (MC service server – MC service server)

Table 10.15.2.9-1 describes the information flow preconfigured regroup cancel request from the MC service server to the MC service server.

Table 10.15.2.9-1 Preconfigured regroup cancel request information elements

Information Element	Status	Description
MC service ID	M	The MC service ID of the requester
MC service group ID	M	MC service group ID of the regroup group

10.15.2.10 Preconfigured regroup cancel response (MC service client – MC service server)

Table 10.15.2.10-1 describes the information flow preconfigured regroup cancel response from the MC service client to the MC service server.

Table 10.15.2.10-1 Preconfigured regroup cancel response information elements

Information Element	Status	Description
MC service ID	M	The MC service ID of the responding MC service client
MC service group ID	M	MC service group ID of the regroup group
Result	M	Result of the regrouping operation

10.15.2.11 Preconfigured regroup cancel response (MC service server – MC service client)

Table 10.15.2.11-1 describes the information flow preconfigured regroup cancel response from the MC service server to the MC service client.

Table 10.15.2.11-1 Preconfigured regroup cancel response information elements

Information Element	Status	Description
MC service ID	M	The MC service ID of the requester of the regroup removal
MC service group ID	M	MC service group ID of the regroup group
Result	M	Result of the regrouping operation

10.15.2.12 Preconfigured regroup cancel response (MC service server – MC service server)

Table 10.15.2.12-1 describes the information flow preconfigured regroup cancel response from the MC service server to the MC service server.

Table 10.15.2.12-1 Preconfigured regroup cancel response information elements

Information Element	Status	Description
MC service ID	M	The MC service ID of the requester of the regroup removal
MC service group ID	M	MC service group ID of the regroup group
Result	M	Result of the regroup removal operation

10.15.2.13 Preconfigured regroup reject (MC service server – MC service client)

Table 10.15.2.13-1 describes the information flow preconfigured regroup reject from the MC service server to the MC service client.

Table 10.15.2.13-1 Preconfigured regroup reject information elements

Information Element	Status	Description
MC service ID	M	The MC service ID of the requester of the regrouping
MC service group ID	M	MC service group ID of the regroup group
Reject reason	M	Reason for rejecting the regrouping operation

10.15.2.14 Preconfigured regroup reject (MC service server – MC service server)

Table 10.15.2.14-1 describes the information flow preconfigured regroup reject from the MC service server to the MC service server.

Table 10.15.2.14-1 Preconfigured regroup reject information elements

Information Element	Status	Description
MC service group ID	M	MC service group ID of the regroup group
Reject reason	M	Reason for rejecting the regrouping operation

10.15.3 Regroup with preconfigured group

10.15.3.1 General

A group regroup may be achieved by regrouping MC service groups into a new MC service regroup group which uses the configuration of a separate preconfigured MC service group. The MC service regroup group configuration needs to be provided to the relevant MC service group members of the MC service groups that will be regrouped in advance of the regrouping operation.

A user regroup may be achieved by regrouping MC service users into a new MC service regroup group which uses the configuration of a separate preconfigured MC service group. The MC service regroup group configuration needs to be provided to the relevant MC service users who will be regrouped in advance of the regrouping operation.

NOTE 1: A preconfigured group which is intended only to provide configuration for the preconfigured regroup process is identified by a parameter in group configuration described in this specification.

NOTE 2: The configuration may alternatively be taken from any MC service group that has been configured in the user profile of all the relevant MC service users who will be regrouped.

NOTE 3: Regroup groups may be defined according to the organizational structure of a mission critical organization, or by some other means which allows the MC service client of an authorized user to be aware of an appropriate regroup group for sets of MC service groups or MC service users that will be regrouped together.

The preconfigured MC service group that provides the configuration is not used as the MC service regroup group itself, it only provides configuration for one or more MC service regroup groups. The MC service group ID of the regroup group is provided by the authorized user when the preconfigured regrouping is carried out.

The MC service regroup group can be specified to be a broadcast or non-broadcast type according to the configuration of the MC service group whose configuration is specified by the regroup request. The broadcast type of regroup is used for one-way communication where only an authorized MC service user is allowed to transmit and all other regroup members are only allowed to receive the communication (e.g. a call from a dispatcher to all regroup members). The non-broadcast type is used for two-way communication where all regroup members can transmit and receive (i.e, the regroup group call behaves like a normal non-broadcast group call).

For group regrouping, if the MC service server has been notified by the group management server that one of the MC service groups that has been requested for regrouping by means of these procedures has already been regrouped, the MC service server shall reject the request for regrouping described in the following procedures.

10.15.3.2 Preconfigured regroup procedures in a single MC system

The following subclauses define group and user regroup procedures using preconfigured groups within a single MC system.

10.15.3.2.1 Preconfigured Group Regroup formation in a single MC system

Figure 10.15.3.2.1-1 illustrates the procedure to initiate a group regroup using a preconfigured MC service group. The procedure takes place prior to the establishment of a group call to the MC service regroup group.

Pre-conditions:

– MC service client 2 is an affiliated member of MC service group 1 and MC service client 3 is an affiliated member of MC service group 2.

– The MC service group identity and group configuration for the preconfigured MC service group have been preconfigured in MC service clients 2 and 3, and MC service clients 2 and 3 have received the relevant security related information to allow them to communicate in the MC service regroup group.

– MC service client 1 is authorized to initiate a preconfigured group regroup procedure.

– MC service client 1 is aware of a suitable MC service group whose configuration has been preconfigured in the MC service UEs of the group members who will be regrouped.

– In order to be aware whether a group is currently regrouped, the MC service server is subscribed to the group configuration in the GMS.

– The GMS has subscribed to group dynamic data from the MC service server using the procedures defined in subclause 10.1.5.6.

Figure 10.15.3.2.1-1: Regroup procedure using preconfigured group in a single MC system

1. The authorized user of MC service client 1 initiates the group regroup procedure, specifying the list of MC service groups to be regrouped (MC service groups 1 and 2), the MC service group ID of the regroup group and the MC service group ID of the group from which configuration information for the regroup group is to be taken.

2. MC service client 1 sends the preconfigured regroup request to the MC service server.

3. The MC service server checks that MC service client 1 is authorized to initiate a preconfigured group regroup procedure, and resolves the group identities of the MC service groups requested in step 1. The MC service server also checks which group members are affiliated to MC service groups 1 and 2. The MC service server may retrieve the configuration for the regroup group from the GMS if that configuration information is not already known to the MC service server. The MC service server also checks that none of the MC service groups that are requested for regrouping are already regrouped by any mechanism.

NOTE 1: This procedure does not require that that the authorized user of MC service client 1 is a group member of MC service groups 1 or 2, or that the authorized user of MC service client 1 is an affiliated group member of MC service groups 1 or 2.

NOTE 2: The list of groups included in the group regroup is held in dynamic data in the MC service server, and is not used to update group configuration information in the group management server.

4. If the MC service server determines that any of the groups requested for regrouping, including the regroup group, have been regrouped by other group regrouping procedures, the MC service server then sends a preconfigured regroup reject back to MC service client 1 with a reject reason indicating that one of the groups has already been regrouped, and this procedure terminates.

5. If the preconfigured regroup request is not rejected, the MC service server sends the preconfigured regroup requests to MC service clients 2 and 3 in steps 5a and 5b respectively.

NOTE 3: Only group members that are affiliated to the MC service groups that are to be regrouped are sent a preconfigured regroup request.

6. MC service clients 2 and 3 notify their users of the regrouping in steps 6a and 6b respectively.

7. MC service clients 2 and 3 may send the preconfigured regroup response to the MC service server to acknowledge the regrouping action. These acknowledgements are not sent in response to a multicast transmission of the preconfigured regroup request.

8. The MC service server affiliates the regrouped MC service clients to the regroup group.

9. The MC service server sends a preconfigured regroup response to MC service client 1.

After the group regrouping procedure, the regrouping remains in effect until explicitly cancelled by the procedure in 10.15.3.2.3.

MC service client participation in the ongoing regroup persists until the MC service client is no longer affiliated to any of the regrouped groups (group 1 or 2 in this procedure).

MC service client affiliation to the regroup group may cease when the UE’s MC service ceases, e.g. when the UE is powered down, or by performing a log-off operation.

Editor’s note: Data persistence in the MC service client following a user log-off or power down needs further study.

10.15.3.2.2 Preconfigured User Regroup formation in a single MC system

Figure 10.15.3.2.2-1 illustrates the procedure to initiate a user regroup procedure using a preconfigured MC service group. The procedure takes place prior to the establishment of a group call to the MC service regroup group.

Pre-conditions:

– MC service clients 2 and 3 are registered with the MC service service.

– MC service client 1 is authorized to initiate a preconfigured user regroup procedure.

– MC service client 1 is aware of a suitable preconfigured group whose configuration has been preconfigured in the MC service UEs of the MC service users who will be regrouped.

Figure 10.15.3.2.2-1: User regroup procedure using preconfigured group in a single MC system

1. The authorized user of MC service client 1 initiates the user regroup procedure, specifying the list of MC service users to be regrouped (MC service clients 2 and 3), the MC service group ID of the regroup group, and the MC service group ID of the group from which configuration information for the regroup group is to be taken.

2. MC service client 1 sends the preconfigured regroup request to the MC service server. The request indicates the list of users to be included in the regroup operation.

3. The MC service server checks that MC service client 1 is authorized to initiate a preconfigured user regroup procedure.

NOTE 1: MC service clients can be involved in multiple user and group regroups simultaneously.

4. The MC service server sends the preconfigured regroup requests to MC service clients 2 and 3 in steps 4a and 4b respectively.

NOTE 2: When using multicast, the MC service server can periodically rebroadcast the preconfigured regroup request.

5. MC service clients 2 and 3 notify their users of the regrouping in steps 5a and 5b respectively.

6. MC service clients 2 and 3 may send the preconfigured regroup response to the MC service server to acknowledge the regrouping action. These acknowledgements are not sent in response to a multicast transmission of the preconfigured regroup request.

7. The MC service server affiliates the regrouped MC service clients to the regroup group.

8. The MC service server sends a preconfigured regroup response to MC service client 1.

NOTE 3: After the user regrouping procedure, the regrouping remains in effect until explicitly cancelled by the procedure in 10.15.3.2.3.

10.15.3.2.3 Preconfigured regroup cancellation in a single MC system

Figure 10.15.3.2.3-1 illustrates the procedure to cancel a group or user regroup that uses a preconfigured MC service group.

Pre-conditions:

– MC service clients 2 and 3 have been regrouped into a MC service regroup group that uses the configuration of a preconfigured MC service group.

– MC service client 1 is authorized to cancel a group or user regroup that uses a preconfigured MC service group.

– The GMS has subscribed to group dynamic data from the MC service server using the procedures defined in subclause 10.1.5.6.

Figure 10.15.3.2.3-1: Cancel preconfigured regroup procedure in a single MC system

1. The authorized user of MC service client 1 initiates the cancellation of the regrouping that uses a preconfigured MC service group.

2. MC service client 1 sends the preconfigured regroup cancel request to the MC service server, specifying the MC service group ID of the regroup group.

3. The MC service server checks that MC service client 1 is authorized to cancel a regrouping that used a regroup procedure with preconfigured groups.

4. The MC service server sends the preconfigured regroup cancel request to MC service clients 2 and 3 (steps 4a and 4b respectively).

5. MC service clients 2 and 3 notify their users of the cancellation of the regrouping in steps 5a and 5b respectively.

6. MC service clients 2 and 3 may send the preconfigured regroup cancel response to the MC service server to acknowledge the cancellation of the regrouping function. These acknowledgements are not sent in response to a multicast transmission of the preconfigured regroup cancel request.

7. The MC service server deaffiliates MC service clients 2 and 3 from the MC service regroup group.

8. The MC service server sends a preconfigured regroup cancel response to MC service client 1.

10.15.3.3 Preconfigured regroup procedures in multiple MC systems

The following subclauses define group and user regroup procedures using preconfigured groups in multiple MC systems.

10.15.3.3.1 Preconfigured Group Regroup formation in multiple MC systems

Figure 10.15.3.3.1-1 illustrates the procedure to initiate a group regroup procedure using a preconfigured MC service group, where at least one of the groups to be regrouped is configured in a partner MC system. The primary MC system where the preconfigured group regrouping is initiated does not need to be aware of the list of group members belonging to groups whose group home system is the partner MC system. If the group management server in the primary MC system of the MC service regroup group shares the necessary security related parameters together with the group configuration of the preconfigured MC service group with the group management server in the partner MC system and the group management server in the partner MC system distributes this configuration including those security parameters to its served MC service users according to the procedures in subclause 10.2.7, the primary MC system does not need to be aware of the list of group members of the MC service regroup group that are receiving service in the partner MC system.

The procedure takes place prior to the establishment of a group call to the MC service regroup group.

In this procedure, any gateway MC servers in the primary or partner MC systems are not shown.

Pre-conditions:

– MC service client 1 is authorized to initiated a preconfigured regroup procedure, and is receiving MC service service in the primary MC system of MC service client 1.

– MC service client 2 is an affiliated member of MC service group 1 where MC service group 1 is defined in the partner MC system and MC service client 2 is receiving service in the partner MC system of MC service client 1.

– The MC service group identity and group configuration for the preconfigured MC service group have been preconfigured in MC service client 2, and MC service client 2 has received the relevant security related information to allow communication in the MC service regroup group.

– In order to be aware whether the group is regrouped, the MC service server is subscribed to the group configuration in the GMS.

– The GMS has subscribed to group dynamic data from the MC service server within the same MC system using the procedures defined in subclause 10.1.5.6

Figure 10.15.3.3.1-1: Group regroup procedure using preconfigured group in multiple MC systems

1. The authorized user of MC service client 1 initiates the group regroup procedure, specifying the list of MC service groups to be regrouped including MC service group 1, the MC service group ID of the regroup group and the MC service group ID of the group from which configuration information for the regroup group is to be taken.

2. MC service client 1 sends the preconfigured regroup request to the MC service server.

3. The MC service server checks that MC service client 1 is authorized to initiate a preconfigured group regroup procedure, and resolves the group identities of the MC service groups requested in step 1. The MC service server also checks which group members are affiliated to the requested MC service groups that are homed in the primary MC system. The MC service server identifies any partner systems which are the group home systems for MC service groups identified in the list of groups to be regrouped. The MC service server may retrieve the configuration for the regroup group from the GMS if that configuration information is not already known to the MC service server. The MC service server also checks that none of the MC service groups that are homed in the primary MC system and that are requested for regrouping are already regrouped by any mechanism.

NOTE 1: This procedure does not require that that the authorized user of MC service client 1 is a group member of the MC service groups listed in the regroup request, or that the authorized user of MC service client 1 is an affiliated group member of any of the listed MC service groups.

4. The MC service server sends the preconfigured regroup requests to the MC service server in the partner MC system.

5. The partner MC service server checks the status of any MC service groups hosted by that partner MC service server, and identifies affiliated group members of any of the identified MC service groups (both MC service groups that are hosted in the primary MC system and MC service groups that are hosted in the partner MC system) that are receiving MC service service in the partner MC system, which include MC service client 2.

6. The partner MC service server sends the preconfigured regroup request to MC service client 2.

NOTE 2: Only group members that are affiliated to the MC service groups that are to be regrouped are sent a preconfigured regroup request.

7. MC service client 2 notifies the user of the regrouping.

8. MC service client 2 may send the preconfigured regroup response to the partner MC service server to acknowledge the regrouping action. This acknowledgement is not sent in response to a multicast transmission of the preconfigured regroup request.

9. The partner MC service server affiliates the regrouped MC service client 2 to the regroup group.

10. The partner MC service server sends a preconfigured regroup response to the primary MC service server.

11. The primary MC service server sends the preconfigured regroup response to MC service client 1.

After the group regrouping procedure, the regrouping remains in effect until explicitly cancelled by the procedure in 10.15.3.3.3.

MC service client participation in the ongoing regroup persists until the MC service client is no longer affiliated to any of the regrouped groups (group 1 or 2 in this procedure).

MC service client affiliation to the regroup group may cease when the UE’s MC service service ceases, e.g. when the UE is powered down, or by performing a log-off operation.

Editor’s note: Data persistence in the MC service client following a user log-off or power down needs further study.

10.15.3.3.2 Preconfigured User Regroup formation in multiple MC systems

Figure 10.15.3.3.2-1 illustrates the procedure to initiate a user regroup procedure using a preconfigured MC service group, where at least one of the MC service users to be regrouped is homed in a partner MC system. It is assumed that the group management server in the primary MC system of the MC service regroup group shares the necessary security related parameters together with the group configuration of the preconfigured MC service group with the group management server in the partner MC system and the group management server in the partner MC system distributes this configuration including those security parameters to its served MC service users according to the procedures in subclause 10.2.7.

The procedure takes place prior to the establishment of a group call to the MC service regroup group.

In this procedure, any gateway MC servers in the primary or partner MC systems are not shown.

Pre-conditions:

– MC service client 1 is homed in the primary MC system and is receiving service in the primary MC system.

– MC service client 2 is homed in the partner MC system and is receiving service in the partner MC service system of MC client 1.

– MC service client 1 is authorized to initiate a preconfigured user regroup procedure.

– MC service client 1 is aware of a suitable preconfigured group whose configuration has been preconfigured in the MC service UEs of the MC service users who will be regrouped.

Figure 10.15.3.3.2-1: User regroup procedure using preconfigured group in multiple MC systems

1. The authorized user of MC service client 1 initiates the user regroup procedure, specifying the list of MC service users to be regrouped including MC service client 2, the MC service group ID of the regroup group, and the MC service group ID of the group from which configuration information for the regroup group is to be taken.

2. MC service client 1 sends the preconfigured regroup request to the primary MC service server. The request indicates the list of users to be included in the regroup operation.

3. The primary MC service server checks that MC service client 1 is authorized to initiate a preconfigured user regroup procedure.

NOTE 1: MC service clients can be involved in multiple user and group regroups simultaneously.

4. The primary MC service server sends the preconfigured regroup requests to the MC service server in the partner MC system.

5. The partner MC service server checks that the primary MC service server is authorized to include MC service users homed in the partner system a user regroup.

6. The partner MC service server sends the preconfigured regroup request to MC service client 2.

7. MC service client 2 notifies the user of the regrouping.

9. The partner MC service server affiliates the regrouped MC service client 2 to the regroup group.

10. The partner MC service server sends a preconfigured regroup response to the primary MC service server.

11. The primary MC service server sends the preconfigured regroup response to MC service client 1.

NOTE 2: After the user regrouping procedure, the regrouping remains in effect until explicitly cancelled by the procedure in 10.15.3.3.3.

10.15.3.3.3 Preconfigured regroup cancellation in multiple MC systems

Figure 10.15.3.3.3-1 illustrates the procedure to cancel a group or user regroup that uses a preconfigured MC service group where multiple MC systems were involved in the regrouping.

Pre-conditions:

– MC service client 2 has been regrouped into the MC service regroup group, and is receiving service in the partner MC system of the regroup group.

– MC service client 1 is authorized to cancel a regrouping that uses a preconfigured MC service group, and is receiving service in the primary MC system of the regroup group.

– The GMS has subscribed to group dynamic data from the MC service server within the same MC system using the procedures defined in subclause 10.1.5.6.

Figure 10.15.3.3.3-1: Cancel preconfigured regroup procedure in multiple MC systems

1. The authorized user of MC service client 1 initiates the cancellation of the regrouping that uses a preconfigured MC service group.

2. MC service client 1 sends the preconfigured regroup cancel request to the MC service server, specifying the MC service group ID of the regroup group.

3. The MC service server checks that MC service client 1 is authorized to cancel a regrouping that uses a preconfigured group regroup procedure.

4. The primary MC service server sends the regroup cancel request to the partner MC service server.

5. The partner MC service server sends the preconfigured regroup cancel requests to MC service client 2.

6. MC service client 2 notifies the user of the cancellation of the group regrouping.

7. MC service client 2 may send the preconfigured regroup cancel response to the partner MC service server to acknowledge the cancellation of the regrouping function. This acknowledgement is not sent in response to a multicast transmission of the preconfigured regroup cancel request.

8. The partner MC service server deaffiliates MC service client 2 from the MC service regroup group.

9. The partner MC service server sends the preconfigured regroup cancel response to the primary MC service server.

10. The primary MC service server sends a preconfigured regroup cancel response to MC service client 1.

10.15.3.3.4 Preconfigured group regroup rejection in multiple MC systems

Figure 10.15.3.3.4-1 illustrates the case where the procedure to initiate a group regroup with multiple MC systems using a preconfigured MC service group described in subclauses 10.15.3.3.1 commences, but where the request for the regroup is rejected by the partner MC service server. The rejection can occur, for example because one of the groups hosted by the partner MC service server is already regrouped by other group regrouping procedures.

In this procedure, any gateway MC servers in the primary or partner MC systems are not shown.

Pre-conditions:

– MC service client 1 is authorized to initiated a preconfigured regroup procedure, and is receiving MC service service in the primary MC system of MC service client 1.

– In order to be aware whether the group is regrouped, the MC service server within the same MC system is subscribed to the group configuration in the GMS.

Figure 10.15.3.3.4-1: Regroup rejection using preconfigured group in multiple MC systems

2. MC service client 1 sends the preconfigured regroup request to the MC service server.

3. The MC service server checks that MC service client 1 is authorized to initiate a preconfigured group regroup procedure, and resolves the group identities of the MC service groups requested in step 1. The MC service server also checks which group members are affiliated to the requested MC service groups that are homed in the primary MC system. The MC service server identifies any partner systems which are the group home systems for MC service groups identified in the list of groups to be regrouped. The MC service server may retrieve the configuration for the regroup group from the GMS if that configuration information is not already known to the MC service server. The MC service server also checks that none of the MC service groups that are homed in the primary MC system and that are requested for regrouping are already regrouped by any mechanism.

4. The MC service server sends the preconfigured regroup requests to the MC service server in the partner MC system.

5. The partner MC service server checks the status of any MC service groups hosted by that partner MC service server, and determines that one or more requested MC service groups has already been regrouped by another group regrouping procedure.

6. The partner MC service server sends a preconfigured regroup reject to the primary MC service server, indicating the reason for rejection.

7. The primary MC service server sends a preconfigured regroup reject to MC service client 1, indicating the reason for rejection.

10.15.3.4 Other preconfigured regroup procedures

10.15.3.4.1 Adding newly affiliated user to preconfigured group regroup

Figure 10.15.3.4.1-1 illustrates the procedure to add a newly affiliated user to an in-progress preconfigured MC service group regroup operation.

Pre-conditions:

– The MC service client is a member of a MC service group that is part of an in-progress preconfigured group regroup operation.

– The MC service group identity and group configuration for the preconfigured MC service group has been preconfigured in the MC service client, and the MC service client has received the relevant security related information to allow it to communicate in the MC service regroup group.

Figure 10.15.3.4.1-1: Procedure to add a newly affiliated user to a preconfigured group regroup

1. The MC service client affiliates to an MC service group that is currently part of an in-progress preconfigured group regroup. The affiliation follows the procedure in section 10.8.3.1 of this specification.

2. The MC service server retrieves the MC service group ID of the regroup group and the MC service group ID of the group from which configuration information for the regroup group is to be taken.

3. The MC service server sends the preconfigured regroup request to the MC service client.

4. The MC service client notifies the user of the regrouping.

5. The MC service client may send the preconfigured regroup response to the MC service server to acknowledge the regrouping action. These acknowledgements are not sent in response to a multicast transmission of the preconfigured regroup request.

6. The MC service server affiliates the regrouped MC service client to the regroup group.

Editor’s note: It is FFS whether this procedure can be generalized to apply to both preconfigured and GMS-based group regrouping.

Editor’s note: Affiliations of the MC service client to the regroup group in the MC service server and coordination to the MC System is FFS.