Section: 5.5.1.2.3 5GMM common procedure initiation
Content: The network may initiate 5GMM common procedures, e.g. the identification, authentication and security procedures during the registration procedure, depending on the information received in the REGISTRATION REQUEST message. If two NAS security mode control procedures are needed to signal an entire unciphered REGISTRATION REQUEST message followed by signalling of selected EPS NAS security algorithms, both NAS security mode control procedures should be initiated as part of 5GMM common procedures of the ongoing registration procedure (see subclause 5.4.2.4). During a registration procedure with 5GS registration type IE set to "emergency registration", if the AMF is configured to support emergency registration for unauthenticated SUCIs, the AMF may choose to skip the authentication procedure even if no 5G NAS security context is available and proceed directly to the execution of the security mode control procedure.