Section: 13.5A Private Service Identity
Content: The Private Service Identity is applicable to a PSI user and is similar to a Private User Identity in the form of a Network Access Identifier (NAI), which is defined in IETF RFC 4282 [53]. The Private Service Identity is operator defined and although not operationally used for registration, authorisation and authentication in the same way as Private User Identity, it enables Public Service Identities to be associated to a Private Service Identity which is required for compatibility with the Cx procedures.