The Namf_Communication_NonUeN2MessageTransfer service operation is specified in clause 5.2.2.2.17 of TS 23.502. The NonUeN2MessageTransfer service operation shall be invoked by the NF Service Consumer (e.g. CBCF or PWS-IWF) to initiate or stop broadcast in one or more cells as indicated in the Warning Area IE. The AMF shall accept the request and respond to the NF Service Consumer immediately. When NonUeN2MessageTransfer service operation is used for PWS services:

1. PWS Write-Replace-Warning Request message (see clause 9.2.26) or the Stop-Warning Request message (see clause 9.2.28) are transferred in an N2 Message Container via the NonUeN2MessageTranfer request operation (along with a number of IEs);
   The N2 Message Container contains all the available elements from the Write-Replace-Warning Request message or the Stop-Warning Request message with the exception of the List of TAIs IE and the Send Write-Replace-Warning Indication IE or the Send Stop-Warning Indication IE. The PWS message in the N2 Message Container is sent by the AMF via N2 to NG-RAN.
2. Write-Replace-Warning Confirm message (see clause 9.2.27) or the Stop-Warning Confirm message (see clause 9.2.29) returned to the NF Service Consumer via the NonUeN2MessageTranfer response operation;
3. the List of TAIs IE shall be used by the AMF to determine to which NG-RAN nodes the N2 Message Container needs to be forwarded to. The List of TAIs IE is not included in the N2 Message Container. If the List of TAIs IE is not present then the message shall be forwarded to all NG-RAN nodes served by the AMF, subject to the RAT Selector NG-RAN;
4. each NonUeN2MessageTransfer message is uniquely identified by the Message Identifier IE, the Serial Number IE and the Message Type IE. These IEs are also included in the N2 Message Container;
5. if the Send Write-Replace-Warning-Indication IE is present in the Write-Replace-Warning Request message then the AMF shall send the associated Write-Replace-Warning Indication message(s) to the NF Service Consumer as specified in clause 9A.2.2.3. The Send Write-Replace-Warning-Indication IE is not included in the N2 Message Container, and
6. if the Send Stop-Warning-Indication IE is present in the Stop-Warning Request message then the AMF shall send the associated Stop-Warning Indication message(s) to the NF Service Consumer as specified in clause 9A.2.2.3. The Send Stop-Warning-Indication IE is not included in the N2 Message Container.

The Namf_Communication_NonUeN2InfoSubscribe service operation is specified in clause 5.2.2.2.18 of TS 23.502. The NonUeN2InfoSubscribe service operation shall be invoked by the NF Service Consumer (e.g. CBCF or PWS-IWF) to subscribe to the delivery of non-UE specific PWS information from the NG-RAN node, e.g. for PWS events, sent via N2 to the AMF. When NonUeN2InfoSubscribe service operation is used for PWS services:

1. The NF Service Consumer ID is an identifier which is configured in the CBCF or PWS-IWF;
2. The N2 information types are:
   • WarningIndications;
   • RestartFailure;
3. if the N2 information type is WarningIndications then the NF Service Consumer subscribes to receiving Write-Replace-Warning Indication messages (see clause 9.2.30) and Stop-Warning Indication messages (see clause 9.2.31) from the AMF, and
4. if the N2 information type is RestartFailure then the NF Service Consumer subscribes to receiving Restart Indications (see clause 9.2.32) and Failure Indications (see clause 9.2. 33) from the NG-RAN node.

The Namf_Communication_NonUeN2InfoUnSubscribe service operation is specified in clause 5.2.2.2.19 of TS 23.502. The NonUeN2InfoUnSubscribe service opration shall be invoked by the NF Service Consumer (e.g. CBCF or PWS-IWF) to unsubscribe to stop notifying non-UE specific N2 information from the NG-RAN node, e.g. for PWS events.

The Namf_Communication_NonUeN2InfoNotify service operation is specified in clause 5.2.2.2.20 of TS 23.502. The NonUeN2InfoNotify service operation is used by AMF to notify a particular PWS event towards the NF Service Consumer (e.g. CBCF or PWS-IWF) that has subscribed for the specific information. The AMF receives messages for such PWS events from NG-RAN via N2. When NonUeN2InfoNotify service operation is used for PWS services, the N2 information consists of all (mandatory and optionally) available information provided via N2 in the Write-Replace Warning Indication (see clause 9.2.30), a Stop Warning Indication (see clause 9.2.31), a PWS Restart Indication (see clause 9.2.32) or a PWS Failure Indication (see clause 9.2.33).

Write-Replace-Warning Request messages and Stop-Warning-Request messages are transported with the NonUeMessageTransfer service operation. The procedure is shown in Figure 9A.2.3.1-1.

Restart and Failure Indications are send by NG-RAN nodes and are forwarded to the CBCF by the AMF if the CBCF has subscribed to receiving such indications. The procedure is shown in Figure 9A.2.3.2-1.