4.11.3a Handover procedures between EPS and 5GC-TNGF

23.5023GPPProcedures for the 5G System (5GS)Release 18TS

4.11.3a.1 Handover from EPS to 5GC-TNGF

The handover procedure from EPS to 5GC-TNGF is supported as specified in clause 4.11.3.1 for handover procedure from EPS to 5GC-N3IWF with the following differences:

– The untrusted non-3GPP access is substituted by trusted non-3GPP access point (TNAP).

– The N3IWF is substituted by TNGF.

– The registration procedure via trusted non-3GPP access as specified in clause 4.12a.2 shall be performed in step 1.

– The UE requested PDU Session Establishment with Existing PDU Session indication in 5GC via trusted non-3GPP access is performed in step 2 as specified clause 4.12a.5.

4.11.3a.2 Handover from 5GC-TNGF to EPS

The handover procedure from 5GC-TNGF to EPS is supported as specified in clause 4.11.3.2 for handover procedure from 5GC-N3IWF to EPS with the following differences:

– The untrusted non-3GPP access is substituted by trusted non-3GPP access point (TNAP).

– The N3IWF is substituted by TNGF.

– The network requested PDU Session Release via TNAP and TNGF shall be initiated as specified in clause 4.12a.7 from steps 3 to 12.