Question: During an MME change in a 5G network, how does the target MME select NAS integrity protection algorithms when receiving updated UE EPS security capabilities via the S10 interface?
Option 1: The target MME selects the first compatible algorithm from the UE's listed security capabilities.
Option 2: The target MME chooses the NAS algorithms with the highest priority based on predefined ordered lists, potentially differing from those used by the source MME.
Option 3: The decision is based solely on the source MME's currently used NAS algorithms, without considering the UE's security capabilities.
Option 4: The target MME randomly selects an algorithm from the intersection of its supported algorithms and the UE's declared capabilities.
Explanation: This correct answer reflects the specified behavior in telecom networks for ensuring seamless security during handovers or changes between Mobility Management Entities (MMEs). By selecting the highest priority NAS integrity protection algorithms from ordered lists, the target MME ensures optimal security based on both its own capabilities and the UE's (User Equipment) declared security capabilities. This approach enhances security by potentially upgrading the protection level if the target MME supports more advanced algorithms than the source MME.