The support of the IP connectivity functionality in the IOPS mode of operation enables that MC services are provided by the MC service clients via the IOPS MC connectivity function. An IOPS MC connectivity function provides IP connectivity for the communication among MC service users based on an IOPS discovery procedure.
The IOPS discovery procedure enables that the IOPS MC connectivity function discovers MC service users within the coverage of the system and receives connectivity information required to establish a communication between discovered users based on the IP connectivity functionality.
The following clauses specify the IOPS discovery procedure and information flows for the IP connectivity functionality in the IOPS mode of operation.
Table 10.2.2.1-1 describes the information flow for the IP connectivity request from the IOPS connectivity client to the IOPS MC connectivity function.
Table 10.2.2.2-1 describes the information flow for the IP connectivity response from the IOPS MC connectivity function to the IOPS connectivity client.
It includes the requesting MC service UE's IP address (NOTE 1)
List of IOPS MC service group ID (NOTE 2)
M
It includes the IOPS group (IOPS MC service group ID and its associated IOPS group IP multicast address) or list of IOPS groups the requesting MC user is configured with
Availability of connectivity information
O
It indicates if the connectivity information of the requesting MC user can be made available to other users on the system
List of IOPS MC service IDs (NOTE 2 and NOTE 3)
O
The specific list of IOPS MC service IDs that the requesting MC user's connectivity information can be shared with
Priority state
M
Indicates whether the requesting MC user is requesting higher priority or not
Table 10.2.2.4-1 describes the information flow for the IOPS discovery response from the IOPS MC connectivity function to the IOPS connectivity client.
After an MC service user is authenticated on the IOPS MC connectivity function, the IOPS discovery procedure is initiated by the MC users requesting support of the IP connectivity functionality to the IOPS MC connectivity function. If the IOPS MC connectivity function indicates the support of the IP connectivity functionality, the MC service users can send an IOPS discovery request.
The procedure for requesting support of the IP connectivity functionality by the IOPS connectivity client to the IOPS MC connectivity function is described in Figure 10.2.3-1.
Pre-conditions:
The MC service user is authenticated on the IOPS MC connectivity function.
The MC service user has an active PDN connection to the IOPS MC connectivity function for the specific IP connectivity functionality procedure
The IOPS connectivity client does not contain information about the support of the IP connectivity functionality by the serving IOPS MC connectivity function
The IOPS MC connectivity function indicates to the IOPS connectivity client if the IP connectivity functionality is supported or not for the MC user.
The procedure for the discovery of MC users in the IOPS mode of operation is described in Figure 10.2.3-2. The IOPS discovery is initiated by the MC users to support MC services based on the IP connectivity functionality.
As part of the IOPS discovery procedure, an MC user can request higher priority from the IOPS MC connectivity function by including a priority state indication within the IOPS discovery request. Based on this indication, the IOPS MC connectivity function can decide to handle with higher priority the transactions related to the MC user, e.g. the distribution of packets related to any MC communication from or to the corresponding MC user, subscriptions, and notifications. When an MC user intends to establish an IOPS emergency (group or private) call, the MC user can request a priority state from the IOPS MC connectivity function.
The MC user's priority state remains unchanged until the MC user explicitly changes it (i.e. by sending a new IOPS discovery request) or the discovery status of the MC user changes to not-discovered on the IOPS MC connectivity function.
Pre-conditions:
The MC service user is authenticated on the IOPS MC connectivity function.
The MC service user has an active PDN connection to the IOPS MC connectivity function for the specific IP connectivity functionality procedure
The IOPS MC connectivity function has indicated to the IOPS connectivity client the support of the IP connectivity functionality.
The MC user sends an IOPS discovery request to the IOPS MC connectivity function. The request includes providing connectivity information for the support of MC services based on the IP connectivity functionality.
The IOPS MC connectivity function provides a response to the IOPS connectivity client indicating the success or failure of the discovery of the requesting MC user.