Section: 5.9.2.4 Requirements on the Service Communication Proxy (SCP)
Content: The SCP has interfaces with Network Functions (NF) and peer SCPs within the PLMN (or SNPN). The interface between the SCP and the NFs and between the two SCPs shall fulfil the following requirements: - Mutual authentication shall be performed between the SCP and NFs, and between the two SCPs within the PLMN (or SNPN). - All communication between the SCP and NFs and between SCPs shall be confidentiality, integrity and replay protected. If SCP endpoints are co-located with the NFs, the above two requirements may be satisfied by colocation. The SCP shall provide confidentiality, integrity and replay protection for its internal communication over SCP internal network interfaces. NOTE 1: All parties communicating through the SCP need to trust the SCP to correctly handle the messages passing through it. If the signalling message (service/subscription request or notification message) from the sending NF does not include the PLMN ID in the 3gpp-Sbi-Originating-Network-Id header and the sending SCP can determine the PLMN-ID value to be included in the 3gpp-Sbi-Originating-Network-Id header, the sending SCP should include it.