Section: 9.5 Interfaces based on DIAMETER or GTP
Content: This clause applies to all DIAMETER or GTP-based interfaces between the 5G Core and other network entities that are not part of the 5G System. These includes the Rx interface between the PCF and the IMS System and the N26 interface between the AMF and the MME. The protection of these interfaces shall be supported according to NDS/IP as specified in TS 33.210[ Network Domain Security (NDS); IP network layer security ]  [3], unless security is provided by other means, e.g. physical security. If (D)TLS is used, implementation and usage shall follow the profile given in clause 6.2 of TS 33.210[ Network Domain Security (NDS); IP network layer security ]  [3] and clause 6.1.3a of TS 33.310[ Network Domain Security (NDS); Authentication Framework (AF) ]  [5]. The cipher suites in RFC 6733 shall not be supported. A SEG may be used to terminate the NDS/IP IPsec tunnels.