Section: 6.2.17 SEPP
Content: The Security Edge Protection Proxy (SEPP) is a non-transparent proxy and supports the following functionality: - Message filtering and policing on inter-PLMN control plane interfaces. NOTE: The SEPP protects the connection between Service Consumers and Service Producers from a security perspective, i.e. the SEPP does not duplicate the Service Authorization applied by the Service Producers as specified in clause 7.1.4. - Topology hiding. Detailed functionality of SEPP, related flows and the N32 reference point, are specified in TS 33.501[ Security architecture and procedures for 5G System ]  [29]. The SEPP applies the above functionality to every Control Plane message in inter-PLMN signalling, acting as a service relay between the actual Service Producer and the actual Service Consumer. For both Service Producer and Consumer, the result of the service relaying is equivalent to a direct service interaction. Every Control Plane message in inter-PLMN signalling between the SEPPs may pass via IPX entities. More details on SEPPs and the IPX entities are described in TS 29.500[ 5G System; Technical Realization of Service Based Architecture; Stage 3 ]  [49] and TS 33.501[ Security architecture and procedures for 5G System ]  [29].