Question: In a GPRS network, how is the location of a Mobile Station (MS) in STANDBY or PMM-IDLE state known to the Serving GPRS Support Node (SGSN), and what is the basis for paging the MS for packet services?
Option 1: The location is known on a Cell ID level, and the MS is paged in all cells within the current Location Area (LA).
Option 2: The location is known on a Routeing Area (RA) level, and the MS is paged only in the RA where the MS is located.
Option 3: The location is known on a Location Area (LA) level, and the MS is paged in all RAs within the current LA.
Option 4: The location is not tracked for MSs in STANDBY or PMM-IDLE state, and paging is done randomly across the network.
Explanation: According to GPRS service description, when an MS is in STANDBY or PMM-IDLE state, its location is known to the SGSN on a Routeing Area (RA) level. For mobile-terminated packet services, the MS is specifically paged in the RA where it is currently located, ensuring efficient use of network resources and minimizing unnecessary paging across larger areas like entire Location Areas (LAs). This approach highlights the importance of RAs in managing mobility and service delivery within GPRS networks.