Section: 5.3.11.3 UE Activity Notification procedure
Content: The UE Activity Notification procedure is illustrated in Figure 5.3.11.3-1. Figure 5.3.11.3-1: UE Activity Procedure 1) The MME receives an indication regarding UE reachability, e.g. an Attach Request message from the UE or MME receive an indication from S-GW that UE has handed over to non-3GPP coverage. 2) If the MME contains an MM context of the UE and if URRP-MME for that UE is configured to report once that the UE is reachable, the MME shall send a UE-Activity-Notification (IMSI, UE-Reachable) message to the HSS and clears the corresponding URRP-MME for that UE. 3) When the HSS receives the UE-Activity-Notification (IMSI, UE-Reachable) message or the Update Location message for an UE that has URRP-MME set, it triggers appropriate notifications to the entities that have subscribed to the HSS for this notification and clears the URRP-MME for that UE.