Content for  TS 38.413  Word version:  17.1.1

The purpose of the Broadcast Session Setup procedure is to request the NG-RAN node to setup MBS resources for an MBS session of a broadcast service. The procedure uses non-UE associated signalling.

The AMF initiates the procedure by sending a BROADCAST SESSION SETUP REQUEST message to the NG-RAN node. If the NG-RAN node accepts all the flows in the MBS session at least in one of its cells, the NG-RAN node responds with the BROADCAST SESSION SETUP RESPONSE message. If the MBS Service Area IE is included in the BROADCAST SESSION SETUP REQUEST message, the NG-RAN node shall take it into account as specified in TS 23.247. If the MBS Session FSA ID List IE is included in the BROADCAST SESSION SETUP REQUEST message, the NG-RAN node shall take it into account to determine cells/frequencies within the MBS service area to broadcast MBS session data as specified in TS 23.247.

If the NG-RAN node is not able to provide the resources for all the flows in the MBS session in any of its cells, it shall send the BROADCAST SESSION SETUP FAILURE message.

Void.

The purpose of the Broadcast Session Modification procedure is to request the NG-RAN node to update the broadcast area or the MBS information related to a previously established MBS session. The procedure uses non-UE associated signalling.

The AMF initiates the procedure by sending a BROADCAST SESSION MODIFICATION REQUEST message to the NG-RAN node. If the MBS Service Area IE is included in the BROADCAST SESSION MODIFICATION REQUEST message, the NG-RAN node shall update the MBS service area and send the BROADCAST SESSION MODIFICATION RESPONSE message. If the MBS Session Modification Request Transfer IE is included in the BROADCAST SESSION MODIFICATION REQUEST message, the NG-RAN node shall replace the previously provided information by the newly received one and update the MBS context and resources as necessary and send the BROADCAST SESSION MODIFICATION RESPONSE message.

If the NG-RAN node fails to update any requested modification, the NG-RAN node shall send the BROADCAST SESSION MODIFICATION FAILURE message.

Void.

The purpose of the Broadcast Session Release procedure is to release the MBS context corresponding to the previous established MBS session. The procedure uses non-UE assocated signalling.

The AMF initiates the procedure by sending a BROADCAST SESSION RELEASE REQUEST message to the NG-RAN node. Upon reception of the BROADCAST SESSION RELEASE REQUEST message, the NG-RAN node shall respond with the BROADCAST SESSION RELEASE RESPONSE message. The NG-RAN node node shall stop broadcasting and release all resources associated with the broadcast session. Upon reception of the BROADCAST SESSION RELEASE RESPONSE message, the AMF shall transfer transparently the Broadcast Session Release Response Transfer IE, if available, to the MB-SMF.

Not applicable.

Void.

The purpose of the Broadcast Session Release Required procedure is to trigger the AMF to release the MBS context corresponding to the previously established MBS session. The procedure uses non-UE associated signalling.

The NG-RAN node initiates the procedure by sending a BROADCAST SESSION RELEASE REQUIRED message to the AMF. Upon receiption of the BROADCAST SESSION RELEASE REQUIRED message, the AMF shall realize there is no adequate resources for NG-RAN node to provide the broadcast service over radio and start to release the MBS context corresponding to the previously established MBS session.

Void.

The purpose of the Distribution Setup procedure is to assign NG-U resources for an MBS session. The procedure uses non-UE-associated signalling.

The NG-RAN node initiates the procedure by sending a DISTRIBUTION SETUP REQUEST message to the AMF. The AMF responds with a DISTRIBUTION SETUP RESPONSE message. For location dependent multicast sessions, the NG-RAN node shall include the MBS Area Session ID IE in the DISTRIBUTION SETUP REQUEST message, and the AMF shall provide the same value of the MBS Area Session ID IE in the DISTRIBUTION SETUP RESPONSE message. If the Shared NG-U Unicast TNL Information IE is included in the MBS Distribution Setup Request Transfer IE in the DISTRIBUTION SETUP REQUEST message, the MB-SMF shall use the included information as the downlink termination point for the shared NG-U transport. If the Shared NG-U Unicast TNL Information IE is not included in the MBS Distribution Setup Request Transfer IE in the DISTRIBUTION SETUP REQUEST message, the MB-SMF shall interpret that the IP multicast is used for this shared NG-U transport, and include the Shared NG-U Multicast TNL Information IE in the MBS Distribution Setup Response Transfer IE in the DISTRIBUTION SETUP RESPONSE message.

In case the shared NG-U transport cannot be setup successfully, the AMF shall respond with the DISTRIBUTION SETUP FAILURE message to the NG-RAN node with an appropriate cause value.

Void.

The purpose of the Distribution Release procedure is to enable the release of an already established NG-U resources for a given MBS session, or for a given area session of the MBS session. The procedure uses non-UE-associated signalling.

The NG-RAN node initiates the procedure by sending a DISTRIBUTION RELEASE REQUEST message. Upon receipt of the DISTRIBUTION RELEASE REQUEST message, the AMF shall send the DISTRIBUTION RELEASE RESPONSE message after successfully removing the corresponding NG-U resource for the MBS session. For location dependent multicast session, the NG-RAN node shall include the MBS Area Session ID IE in the DISTRIBUTION RELEASE REQUEST message, and the AMF shall provide the same value of the MBS Area Session ID IE in the DISTRIBUTION RELEASE RESPONSE message. If unicast shared NG-U transport is used, the NG-RAN node shall include the Shared NG-U TNL Information IE in the MBS Distribution Release Request Transfer IE in the DISTRIBUTION RELEASE REQUEST message, and the MB-SMF shall release the corresponding shared NG-U transport as specified in TS 23.247.

Not applicable.

Void.

The purpose of the Multicast Session Activation procedure is to request a NG-RAN node to activate the MBS resources of one MBS session. The procedure uses non-UE-associated signalling.

The AMF initiates the procedure by sending a MULTICAST SESSION ACTIVATION REQUEST message to the NG-RAN node. Upon receipt of the MULTICAST SESSION ACTIVATION REQUEST, the NG-RAN node activates the MBS resources corresponding to the MBS session indicated in the MULTICAST SESSION ACTIVATION REQUEST message and indicates in the MULTICAST SESSION ACTIVATION RESPONSE message for which MBS session the request was fulfilled.

If the NG-RAN node cannot activate the MBS resources indicated in the MULTICAST SESSION ACTIVATION REQUEST message, it shall respond with a MULTICAST SESSION ACTIVATION FAILURE message with an appropriate cause value.

Void.

The purpose of the Multicast Session Deactivation procedure is to request a NG-RAN node to deactivate the MBS resources of one MBS session. The procedure uses non-UE-associated signalling.

The AMF initiates the procedure by sending a MULTICAST SESSION DEACTIVATION REQUEST message to the NG-RAN node. Upon receipt of this message, the NG-RAN node shall deactivate the MBS resources corresponding to the MBS session indicated in the MULTICAST SESSION DEACTIVATION REQUEST message and shall indicate in the MULTICAST SESSION DEACTIVATION RESPONSE message for which MBS session the request was fulfilled.

Not applicable.

Void.

The purpose of the Multicast Session Update procedure is to request the NG-RAN node to update the MBS service area and/or the MBS QoS information related to a MBS session, or to an area session of a location dependent multicast session. The procedure uses non-UE associated signalling.

The AMF initiates the procedure by sending a MULTICAST SESSION UPDATE REQUEST message to the NG-RAN node. Upon receipt of the MULTICAST SESSION UPDATE REQUEST message, the NG-RAN node shall update the QoS profile and/or MBS Service Area for the multicast service and send the MULTICAST SESSION UPDATE RESPONSE message to the AMF. For location dependent multicast session, the AMF shall include the MBS Area Session ID IE in the MULTICAST SESSION UPDATE REQUEST message, and the NG-RAN node shall provide the same value of the MBS Area Session ID IE in the MULTICAST SESSION UPDATE RESPONSE message. In case the MBS Service Area Information IE is included in the Multicast Session Update Request Transfer IE in the MULTICAST SESSION UPDATE REQUEST message, the NG-RAN node shall update the stored MBS Service Area Information for that service, as specified in TS 23.247. In case the MBS QoS Flows To Be Setup or Modify List IE is included in the Multicast Session Update Request Transfer IE in the MULTICAST SESSION UPDATE REQUEST message, the NG-RAN node shall setup or modify the MBS QoS information accordingly. In case the MBS QoS Flows To Be Release List IE is included in the Multicast Session Update Request Transfer IE in the MULTICAST SESSION UPDATE REQUEST message, the NG-RAN node shall release the indicated MBS QoS flows.

If the NG-RAN node is not able to perform any of the requested update, it shall respond with a MULTICAST SESSION UPDATE FAILURE message with an appropriate cause value.

Void.