LTE: Authentication Reject

Ø      Upon receipt of an AUTHENTICATION RESPONSE message the MME compares the received RES value with the XRES (Expected Response) value. If RES == XRES, then the network considers that the UE has successfully authenticated itself to the network

Ø      If the AUTHENTICATION RESPONSE returned by the UE is not valid i.e. RES != XRES, then the network response depends upon the type of identity used by the UE in the initial NAS message as explained below:

·           If the GUTI was used, the network should initiate an identification procedure to obtain IMSI from the UE. If the IMSI given by the UE during the identification procedure differs from the IMSI the network had associated with the GUTI, the authentication should be restarted with the correct parameters. Otherwise, if the IMSI provided by the UE is the same as the IMSI stored in the network (i.e. authentication has really failed), the network should sends AUTHENTICATION REJECT message to the UE

·           If the IMSI was used for identification in the initial NAS message, or the network decides not to initiate the identification procedure after an unsuccessful authentication procedure, the network should send an AUTHENTICATION REJECT message to the UE

Ø       Upon receipt of an AUTHENTICATION REJECT message, the UE shall abort any EMM signalling procedure and enter state EMM-DEREGISTERED. Also, the UE shall set the update status to EU3 ROAMING NOT ALLOWED, delete the stored GUTI, TAI list, last visited registered TAI and KSI_ASME. The USIM shall be considered as invalid until switching off the UE or the UICC containing the USIM is removed

Ø      Additionally, If A/Gb or Iu mode is supported by the UE, it shall handle MM/GMM states and parameters as explained in 3GPP TS 24.008 section 4.7.4.5

Reference: 3GPP TS 24.301

Example: AUTHENTICATION REJECT