Question: What information is included in the authentication failure report sent from the VLR/SGSN to the HLR?
Option 1: Subscriber identity, failure cause code, access type, authentication re-attempt, VLR/SGSN address, and a unique identifier for the failed Authentication Vector (AV).
Option 2: Only subscriber identity and failure cause code.
Option 3: Subscriber identity, access type, and VLR/SGSN address.
Option 4: Failure cause code, authentication re-attempt, and a unique identifier for the failed AV.
Explanation: The authentication failure report sent from the VLR/SGSN to the HLR includes several pieces of information to help the Home Environment (HE) identify and potentially cancel the location of the user. This information includes subscriber identity, failure cause code, access type, authentication re-attempt, VLR/SGSN address, and a unique identifier for the failed AV.