Section: 4.11 System interworking procedures with EPC 4.11.0 General
Content: Clause 4.11 includes the following: - Procedures for interworking with EPS based on N26 interface (clause 4.11.1) and interworking without N26 interface (clause 4.11.2); - Handover procedures between EPS and 5GC-N3IWF (clause 4.11.3), handover procedures between EPS and 5GC-TNGF (clause 4.11.3a) and handover procedures between EPC/ePDG and 5GS (clause 4.11.4); - Impact to 5GC procedure due to interworking with EPC (clause 4.11.5); - Interworking for common network exposure (clause 4.11.6). In clause 4.11, UEs are assumed to support both 5GC NAS and EPC NAS unless explicitly stated otherwise. The procedures in clause 4.11 are not applicable for Disaster Roaming service (see clause 5.40 of TS 23.501[ System architecture for the 5G System (5GS) ]  [2]).