Content for TS 23.180 Word version: 19.0.0
10.3 IOPS subscription and notification (IP connectivity functionality)
10.4 Use of broadcast/multicast transmissions
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10.3 IOPS subscription and notification (IP connectivity functionality) p. 24
10.3.1 General p. 24
The support of the IP connectivity functionality in the IOPS mode of operation enables that MC services are provided by the MC service clients over the IOPS MC connectivity function. An MC user that has been discovered by the IOPS MC connectivity function can subscribe to be notified about the connectivity information of other discovered MC users on the IOPS MC connectivity function. Also, a discovered MC user can subscribe to be notified about the number of other discovered MC users on the IOPS MC connectivity function within its associated IOPS groups.
The following clauses specify the IOPS subscription and notification procedures and information flows for the IP connectivity functionality in the IOPS mode of operation.
10.3.2 Information flows p. 24
10.3.2.1 IP connectivity subscribe request p. 24
Table 10.3.2.1-1 describes the information flow for the IP connectivity subscribe request from the IOPS connectivity client to the IOPS MC connectivity function.
| Information Element | Status | Description |
|---|---|---|
| IOPS MC service ID | M | The IOPS MC service ID of the requesting MC user |
| List of IOPS MC service IDs (see NOTE 1) | O | List of IOPS MC service IDs the requesting MC user subscribes to receive connectivity information from |
| List of IOPS groups (see NOTE 1 and NOTE 2) | O | List of IOPS groups (IOPS MC service group IDs) the requesting MC user subscribes to receive group connectivity information from |
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NOTE 1:
The list of IOPS MC service IDs or IOPS MC service group IDs shall be of the same MC service as the MC user subscribing to receive the connectivity information. At least one should be present.
NOTE 2:
The IOPS group(s) should belong to the list of IOPS groups the requesting MC user included in its IOPS discovery request.
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10.3.2.2 IP connectivity subscribe response p. 24
Table 10.3.2.2-1 describes the information flow for the IP connectivity subscribe response from the IOPS MC connectivity function to the IOPS connectivity client.
| Information Element | Status | Description |
|---|---|---|
| IOPS MC service ID | M | The IOPS MC service ID of the requesting MC user |
| Subscription status | M | It lists the subscription status, success or failure, of the requested subscription(s) |
10.3.2.3 IP connectivity notify request p. 24
Table 10.3.2.3-1 describes the information flow for the IP connectivity notify request from the IOPS MC connectivity function to the IOPS connectivity client.
| Information Element | Status | Description |
|---|---|---|
| IOPS MC service ID | M | The IOPS MC service ID of the MC user with active subscription(s) |
| IOPS MC service ID (see NOTE 1) | M | The IOPS MC service ID associated to the active subscription for which connectivity information is being notified |
| Connectivity information (see NOTE 1) | M | It provides connectivity information about the MC service ID of the corresponding subscription. It includes the MC service UE's IP address of the associated IOPS MC service ID in the system and its connectivity status on the system (see NOTE 2) |
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NOTE 1:
It can be a list associated to multiple active subscriptions.
NOTE 2:
Whether the IOPS MC connectivity function provides within the IP connectivity notify request the actual MC service UE's IP address or an associated application IP address assigned by the IOPS MC connectivity function is implementation specific. For the latter, it is up to the IOPS MC connectivity function to correctly maintain the defined association.
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10.3.2.4 IP connectivity notify response p. 25
Table 10.3.2.4-1 describes the information flow for the IP connectivity notify response from the IOPS connectivity client to the IOPS MC connectivity function.
| Information Element | Status | Description |
|---|---|---|
| IOPS MC service ID | M | The IOPS MC service ID of the responding MC user |
| IOPS MC service ID (see NOTE) | M | The IOPS MC service ID for which connectivity information was received |
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NOTE:
It can be a list associated to multiple active subscriptions.
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10.3.2.5 IP connectivity group notify request p. 25
Table 10.3.2.5-1 describes the information flow for the IP connectivity group notify request from the IOPS MC connectivity function to the IOPS connectivity client.
| Information Element | Status | Description |
|---|---|---|
| IOPS MC service ID | M | The IOPS MC service ID of the MC user with active subscription(s) |
| IOPS group (see NOTE) | M | The IOPS MC service group ID related to the active group subscription for which group connectivity information is being notified |
| Group connectivity information (see NOTE) | M | It indicates the number of other discovered MC users on the IOPS MC connectivity function of the corresponding group subscription |
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NOTE:
It can be a list associated to multiple active group subscriptions.
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10.3.2.6 IP connectivity group notify response p. 25
Table 10.3.2.6-1 describes the information flow for the IP connectivity group notify response from the IOPS connectivity client to the IOPS MC connectivity function.
| Information Element | Status | Description |
|---|---|---|
| IOPS MC service ID | M | The IOPS MC service ID of the responding MC user |
| IOPS group (see NOTE) | M | The IOPS MC service group ID for which group connectivity information was received |
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NOTE:
It can be a list associated to multiple active group subscriptions.
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10.3.3 Procedures p. 26
The procedure for the IP connectivity subscription of MC users in the IOPS mode of operation is described in Figure 10.3.3-1.
Pre-conditions:
- The MC service user has an active PDN connection or PDU session to the IOPS MC connectivity function for the specific IP connectivity functionality procedure
- The MC service user is discovered by the IOPS MC connectivity function to support MC services based on the IP connectivity functionality.
- The MC service user has decided to subscribe to receive connectivity information of other discovered MC users and/or IOPS groups on the IOPS MC connectivity function.
Step 1.
The procedure for the IP connectivity notification of MC users in the IOPS mode of operation is described in Figure 10.3.3-2.
Pre-conditions:
The IOPS connectivity client subscribes to receive connectivity information of other discovered MC users and/or groups on the IOPS MC connectivity function.
Step 2.
The IOPS MC connectivity function checks if a subscription for the MC service ID(s) and/or IOPS group(s) included in the request can be activated for the requesting MC user.
Step 3.
The IOPS MC connectivity function indicates to the IOPS connectivity client the subscription status associated to the request.
- The MC service user has an active PDN connection or PDU session to the IOPS MC connectivity function for the specific IP connectivity functionality procedure
- The MC service user has an active IP connectivity subscription associated to one or multiple MC service IDs.
- The IOPS MC connectivity function has available information related to an IP connectivity subscription associated to one or multiple MC service IDs.
Step 1.
The procedure for the IP connectivity group notification of MC users in the IOPS mode of operation is described in Figure 10.3.3-3.
Pre-conditions:
The IOPS MC connectivity function notifies to the IOPS connectivity client the connectivity information related to an active IP connectivity subscription associated to one or multiple MC service IDs. The connectivity information can be retrieved by the MC service client to establish an MC service communication based on the IP connectivity functionality.
Step 2.
The IOPS connectivity client provides an IP connectivity notify response to the IOPS MC connectivity function.
- The MC service user has an active PDN connection or PDU session to the IOPS MC connectivity function for the specific IP connectivity functionality procedure
- The MC service user has an active IP connectivity subscription associated to one or multiple IOPS MC service group IDs.
- The IOPS MC connectivity function has available information related to an IP connectivity subscription associated to one or multiple IOPS MC service group IDs.
Step 1.
The IOPS MC connectivity function notifies to the IOPS connectivity client the group connectivity information related to an active IP connectivity group subscription associated to one or multiple IOPS MC service group IDs. The group connectivity information can be retrieved by the MC service client to establish an MC service group communication based on the IP connectivity functionality.
Step 2.
The IOPS connectivity client provides an IP connectivity group notify response to the IOPS MC connectivity function.
10.4 Use of broadcast/multicast transmissions p. 28
10.4.1 General p. 28
An IOPS MC connectivity function can provide support for group communications based on broadcast/multicast transmissions. Broadcast/multicast transmissions can be used for the downlink delivery of MC service application signalling and media to the MC service UEs over broadcast/multicast session (e.g., MBMS bearers in EPS, MBS session in 5GS).
The use of broadcast/multicast transmissions in the IOPS mode of operation are based on the related information flows and procedures specified in TS 23.280, TS 23.379, TS 23.282, and TS 23.289.
10.4.2 Information flows p. 28
10.4.2.1 MapIOPSGroupToNetworkSession (IP connectivity functionality) p. 28
Table 10.4.2.1-1 describes the information flow to associate a group session based on the IP connectivity functionality to a broadcast/multicast session. It is sent from the IOPS MC connectivity function to the MC service client.
| Information Element | Status | Description |
|---|---|---|
| IOPS MC service group ID | M | This element identifies the IOPS MC service group, in which the group session is started. |
| Media stream identifier | M | This element identifies the media stream of the SDP used for the group session (e.g. MBMS subchannel). |
| Identifier of broadcast/multicast session (see NOTE) | O | The identifier of the network broadcast/multicast session (e.g., TMGI) if the media of the group session is not sent on the same broadcast/multicast session as this MapIOPSGroupToNetworkSession message. |
| Session acknowledgement indicator | O | Indication that the group session requires acknowledgement from receiving MC service clients. |
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NOTE:
"Identifier of broadcast/multicast session" IE shall be present if this message is sent over a different broadcast/multicast session than the media of the group session; This IE may be present if this message is sent over the same broadcast/multicast session as the media of the group session.
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10.4.2.2 UnmapIOPSGroupFromNetworkSession (IP connectivity functionality) p. 28
Table 10.4.2.2-1 describes the information flow to disconnect a group session based on the IP connectivity functionality from a broadcast/multicast session. It is sent from the IOPS MC connectivity function to the MC service client.
| Information Element | Status | Description |
|---|---|---|
| IOPS MC service group ID | M | This element identifies the IOPS MC service group, in which the group session is started. |
10.4.3 Use of pre-established broadcast/multicast session p. 28
The MC services in the IOPS mode of operation shall support the procedure for using pre-established broadcast/multicast session as specified TS 23.280 or TS 23.289 with the following clarification:
- The MC service server is the IOPS MC connectivity function.
10.4.4 Use of dynamic broadcast/multicast session establishment p. 29
The MC services in the IOPS mode of operation shall support the procedure for using dynamic broadcast/multicast session as specified TS 23.280 or TS 23.289 with the following clarification:
- The MC service server is the IOPS MC connectivity function.
10.4.5 Group session connect and disconnect over broadcast/multicast session (IP connectivity functionality) p. 29
10.4.5.1 General p. 29
MBMS bearers can be used for group sessions based on the IP connectivity functionality. One broadcast/multicast session can be associated to one or more specific groups or group sessions. Before sending packets related to a group session, i.e. signalling and media, over a broadcast/multicast session, the IOPS MC connectivity function transmits the association information between the group session and the broadcast/multicast session. When the group session over the broadcast/multicast session is finished, this temporary association information of a group session to specific resources on a broadcast/multicast session is undone. Prior to the association of a group session to a broadcast/multicast session the broadcast/multicast session is activated and announced to the MC service clients.
10.4.5.2 Procedure p. 29
10.4.5.2.1 Group Session connect over broadcast/multicast session p. 29
In Figure 10.4.5.2.1-1 the MC service client 1 is the client that initiates a group session, e.g. an MCPTT client initiating a group call. The MC service client 1 may be within the broadcast/multicast service area. The MC service clients 2 … n represent MC service clients, e.g. MCPTT clients, receiving the group session packets over an MBMS bearer. There may be other receiving MC service clients both over unicast bearers and over this or other broadcast/multicast session(s), however, they are not illustrated in this Figure.
Pre-conditions:
- The MC service user profile used for the IOPS mode of operation is pre-provisioned in the MC service UEs
- The IOPS MC service group ID and its associated IOPS group IP multicast address are pre-configured in the MC service clients
- The MC service users have an active PDN connection to the IOPS MC connectivity function for the communication based on the IP connectivity functionality
- The MC service users are discovered by the IOPS MC connectivity function to support MC services based on the IP connectivity functionality
Step 1.
Activation and announcement of broadcast/multicast session availability.
Step 2.
MC user at the MC service client 1 wants to initiate an MC service group session with a specific IOPS MC service group based on the IP connectivity functionality.
Step 3.
The MC service client 1 transmits the related group session packets via the IOPS MC connectivity function targeting the IOPS MC service group (i.e. using the corresponding IOPS group IP multicast address)
Step 4.
The IOPS MC connectivity function determines that the received packets correspond to a group session. Therefore, the IOPS MC connectivity function transmits a MapIOPSGroupToNetwork message over a previously established broadcast/multicast session to all users monitoring the broadcast/multicast session. The MapIOPSGroupToNetwork message includes association information between the group session and the broadcast/multicast session. It includes the corresponding IOPS MC service group ID associated to the IOPS group IP multicast address related to the group session.
Step 5.
The IOPS MC connectivity function distributes the received group session packets from the MC service client 1 to other MC service clients (e.g. MC service clients 2 … n) over the broadcast/multicast session.
10.4.5.2.2 Group session disconnect over broadcast/multicast session p. 30
Figure 10.4.5.2.2-1 shows the high-level procedure where an UnmapIOPSGroupFromNetworkSession message is transmitted from the IOPS MC connectivity function to MC service clients to indicate that a group session is being disconnected or dissociated from the broadcast/multicast session.
Step 1.
A group session based on the IP connectivity functionality is ongoing; the group session packets received from the MC service client 1 are distributed over broadcast/multicast session to other MC service clients within the system.
Step 2.
The IOPS MC connectivity function has determined to disconnect the group session from the broadcast/multicast session for the MC service clients within the system.
Step 3.
An UnmapGroupFromBearer message is transmitted from the IOPS MC connectivity function to the MC service clients and possibly to the MC service client 1 (if it is within the broadcast/multicast coverage area) on broadcast/multicast session(s).
