Question: When should a new 5G-GUTI be sent to a User Equipment (UE) in response to a Service Request message?
Option 1: Only after a successful activation of AS security
Option 2: Before the current NAS signalling connection is released or the N1 NAS signalling connection is suspended, but only if the Service Request message was triggered by the network.
Option 3: Immediately after receiving the Service Request message from the UE, regardless of whether it was triggered by the network or not.
Option 4: Before the current NAS signalling connection is released or the suspension of the N1 NAS signalling connection, and this can be sent in response to a Service Request message sent by the UE in response to a Paging message.
Explanation: According to the security architecture and procedures for 5G System, a new 5G-GUTI should be sent to a UE before the current NAS signalling connection is released or the suspension of the N1 NAS signalling connection, and this can be sent in response to a Service Request message sent by the UE in response to a Paging message. This ensures that the UE receives a new 5G-GUTI after a successful activation of NAS security, which is essential for secure communication in the 5G network.