10.2 IOPS discovery (IP connectivity functionality)
23.1803GPPMission critical services support in the Isolated Operation for Public Safety (IOPS) mode of operationRelease 17TS
10.2.1 General
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.
10.2.2 Information flows
10.2.2.1 IP connectivity request
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 10.2.2.1-1: IP connectivity request
|
Information element |
Status |
Description |
|
IOPS MC service ID |
M |
The IOPS MC service ID of the user requesting support of the IP connectivity functionality |
10.2.2.2 IP connectivity response
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.
Table 10.2.2.2-1: IP connectivity response
|
Information element |
Status |
Description |
|
IOPS MC service ID |
M |
The IOPS MC service ID of the user requesting support of the IP connectivity functionality |
|
IP connectivity support |
M |
It indicates if the IP connectivity functionality is supported or not for the user |
10.2.2.3 IOPS discovery request
Table 10.2.2.3-1 describes the information flow for the IOPS discovery request from the IOPS connectivity client to the IOPS MC connectivity function.
Table 10.2.2.3-1: IOPS discovery request
|
Information element |
Status |
Description |
|
IOPS MC service ID |
M |
The IOPS MC service ID of the requesting MC user |
|
IP connectivity information |
M |
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 |
|
NOTE 1: The MC service UE’s IP address is assigned by the IOPS EPS based on the PDN connection established by the MC user for the IOPS IP connectivity functionality. NOTE 2: The list of IOPS MC service IDs or IOPS MC service group IDs shall be of the same MC service as the MC user requesting to be discovered. NOTE 3: If present, the user’s connectivity information availability can be only made available to the provided specific list of IOPS MC service IDs. |
||
10.2.2.4 IOPS discovery response
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.
Table 10.2.2.4-1: IOPS discovery response
|
Information element |
Status |
Description |
|
IOPS MC service ID |
M |
The IOPS MC service ID of the user requesting to be discovered |
|
Connectivity status |
M |
It indicates the connectivity status of the requesting MC user on the system |
|
IOPS discovery request periodicity |
M |
It indicates the periodicity at which the requesting MC user is required to transmit IOPS discovery requests (NOTE) |
|
NOTE: An MC user is required to periodically transmit an IOPS discovery request. The periodic IOPS discovery requests are used by the IOPS MC connectivity function to verify the availability of the MC user and its IP connectivity information within the IOPS MC system. |
||
10.2.3 Procedure
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.
NOTE 1: The procedure for requesting support of the IP connectivity functionality is only required when the IOPS connectivity client does not contain information about the support of this functionality by the serving 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 connectivity client does not contain information about the support of the IP connectivity functionality by the serving IOPS MC connectivity function
Figure 10.2.3-1 IP connectivity functionality request in the IOPS mode of operation
1. The IOPS connectivity client requests to the IOPS MC connectivity function the support of the IP connectivity functionality.
2. 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.
Figure 10.2.3-2 User discovery in the IOPS mode of operation
1. 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.
2. The IOPS MC connectivity function stores the information received from the MC user and registers the user’s connectivity status as discovered.
3. 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.
NOTE 2: The MC user shall send a new IOPS discovery request to update or modify information elements.
NOTE 3: The IOPS MC connectivity function shall send a new IOPS discovery response to the IOPS connectivity client for the case that the periodic IOPS discovery request has not been received yet or when the IOPS discovery request periodicity needs to be changed. The IOPS MC connectivity function can verify the availability and IP connectivity information of the discovered MC user within the IOPS MC system based on the reception of periodic IOPS discovery requests.