Section: 5.17.5.2.2 Interworking without N26 interface
Content: In addition to the interworking principles documented in clause 5.17.2.3, the additional behaviour at EPS to 5GS mobility in clause 5.17.5.2.1 also applies. When SCEF+NEF performs the procedure of monitoring via the AMF as described in clause 4.15.3.2.4 ("Exposure with bulk subscription") in TS 23.502[ Procedures for the 5G System (5GS) ]  [3], if the AMF determines the interworking without N26 interface is supported, during mobility from 5GS to EPS, the AMF shall subscribe on behalf of SCEF+NEF for UDM+HSS notification of MME ID as described in clause 7.1.2 to trigger the SCEF+NEF to configure the monitoring request to the new MME. For single-registration mode, when UE's mobility from 5GS to EPS happens and Serving MME sends Update Location Request to the UDM+HSS, the UDM+HSS provides Serving MME ID to the SCEF+NEF which is the notification endpoint based on the subscription request from AMF. Then the SCEF+NEF performs the procedure of configuring monitoring via the MME for the same Monitoring Events as described in clause 5.6.2.1 of TS 23.682[ Architecture enhancements to facilitate communications with packet data networks and applications ]  [36]. When SCEF+NEF performs the procedure of monitoring via the UDM+HSS as described in clause 4.15.3.2.2 of TS 23.502[ Procedures for the 5G System (5GS) ]  [3], when UE's mobility between 5GS and EPS happens, the UDM+HSS performs the procedure of configuring monitoring at the MME as described in clause 5.6.1.1 of TS 23.682[ Architecture enhancements to facilitate communications with packet data networks and applications ]  [36] and at the AMF as described in clause 4.15.3.2.1 of TS 23.502[ Procedures for the 5G System (5GS) ]  [3].