Question: How does a User Equipment (UE) convey Network Slice Selection Assistance Information (NSSAI) to the network?
Option 1: Through Non-Access Stratum (NAS) signaling
Option 2: Over X2 interface between eNodeBs
Option 3: Using DNS queries to resolve slice information
Option 4: Over Radio Resource Control (RRC) in a format indicated by the upper layer
Explanation: The UE conveys NSSAI over RRC, as specified in the 3GPP TS 38.300 standard, when triggered by the upper layer. This is done to assist the network in selecting the appropriate network slice for the UE's communication needs.