MSGin5G device triggering is the means by which an Application Server sends an MSGin5G message and the 3GPP network device triggering capabilities exposed via T8 /N33 reference point are leveraged. For example, when an Application Server initiates an MSGin5G message request, but the target UE is not reachable, the MSGin5G Server may use the 3GPP network device triggering mechanism to wake up the device and provide the payload to the destination.
If the MSGin5G Server determines that the recipient MSGin5G Client is not reachable, it initiates a device trigger request via the SCEF/NEF as a result of the step 1 request.
To determine the reachability of the target UE, the MSGin5G Server may use the UE reachability status monitoring procedure in clause 8.9.2. The MSGin5G Server may also use availability information provided by the MSGin5G Client at registration in the MSGin5G Client Communication Availability IE, as detailed in Table 8.2.1-1.
The MSGin5G Server sends a request for Device Triggering via SCEF/NEF and determines the flow as detailed in clause 18.104.22.168.2. The Device Triggering request uses the UE Identifier, port number(s) and associated protocol information provided by the MSGin5G Client at registration in the MSGin5G Client Triggering Information IE.
The MSGin5G Server may use MSGin5G Client Communication Availability and/or pre-configured information to determine the timing of the Device Triggering request, e.g. the trigger may be sent to ensure that the target UE is reachable prior to resuming MSGin5G communications.
The device trigger is delivered to the target via SCEF/NEF and the Core Network. The targeted MSGin5G Client or Application Client receives the device trigger request. The targeted MSGin5G Client or Application Client parses the payload of the trigger request and determines the device trigger purpose. The target UE becomes reachable, and the MSGin5G Client or Application Client becomes available for further MSGin5G communications.
The MSGin5G Server responds to the request received in step 1.
Based on the trigger purpose derived from the payload, the targeted MSGin5G Client or Application Client performs the corresponding actions (e.g. establish access network connectivity, contact the Application Server etc).