Section: 13.3.7 Authentication and authorization between SCPs
Content: SCPs shall use one of the following methods as described in 13.1 to mutually authenticate each other before service layer messages can be exchanged on that interface: - If the PLMN uses protection at the transport layer, authentication provided by the transport layer protection solution shall be used for mutual authentication of the SCPs. - If the PLMN does not use protection at the transport layer, mutual authentication of the two SCPs may be implicit by NDS/IP or physical security. Authorization between SCPs is based on local authorization policy.