Question: Where is the Network Layer Service Access Point Identifier (NSAPI) conditionally stored in a telecom network?
Option 1: Only in the Mobile Switching Center (MSC)
Option 2: Only in the Home Location Register (HLR)
Option 3: In both the Serving GPRS Support Node (SGSN) and the Gateway GPRS Support Node (GGSN), but not in the HLR
Option 4: Exclusively in the User Equipment (UE)
Explanation: The NSAPI, holding the index of the PDP Context, is identified as temporary subscriber data. Such data related to packet-switched services are conditionally stored in nodes managing GPRS sessions, namely the SGSN for subscribers' session management and the GGSN for interfacing with external networks, facilitating efficient handling of packet data transmissions.