Question: What is the purpose of including the eKSI (KSIASME) in the NAS Key Set Identifier IE in the ATTACH REQUEST message during the attach procedure for a UE performing initial registration?
Option 1: To indicate the UE's support for 5G services
Option 2: To provide the UE's current location to the network
Option 3: To integrity protect the ATTACH REQUEST message with the current EPS security context
Option 4: To request a specific QoS profile from the network
Explanation: The eKSI (KSIASME) is included in the NAS Key Set Identifier IE to allow the UE to integrity protect the ATTACH REQUEST message with the current EPS security context. This ensures that the message is authenticated and protected against tampering or eavesdropping, which is essential for maintaining the security of the EPS network.