Amf reallocation handling using ue exceptions to security context rules

Abstract

A UE having a security context with an Initial AMF is able to accept an unprotected AUTHRQ, under certain circumstances, for a limited time. In one embodiment, a UE considers the security context to be temporary, which invokes rules or exceptions different than a permanent security context, such as the acceptance of an unprotected AUTHRQ from a Target AMF. The network may indicate to the UE the temporary status, or the UE may assume it. Alternatively, the UE may enable exceptions to the defined rules associated with the security context. In one embodiment, the UE receives a plurality of partial registration acceptance messages, each indicating a specific task or aspect of the overall registration has been completed. The UE may mark its security context temporary, or enable exceptions to the rulesassociated with it, until a partial registration acceptance messages indicates AMF re-allocation is complete or is not required. In another embodiment, the UE accepts unprotected authentication messages from the network until the Registration procedure is completed, enabling a Target AMF to successfully send it an unprotected AUTHRQ.