Question: What triggers a GGSN to send a Send Routing Information for GPRS Request message to a GTP-MAP protocol-converting GSN, according to standard telecom protocols?
Option 1: Establishment of a new PDP context with an unknown SGSN IP address
Option 2: No established PDP context and the need to determine the MS's SGSN IP address using IMSI
Option 3: Receipt of a Create PDP Context Request from an unknown UE
Option 4: Expiration of a timer for periodic routing updates in the GPRS network
Explanation: In telecom networks, especially those utilizing GPRS, determining the location of a Mobile Station (MS) is crucial for routing data correctly. When no PDP context is established, the Gateway GPRS Support Node (GGSN) needs to identify the Serving GPRS Support Node (SGSN) associated with the MS using the IMSI. This process ensures efficient data routing in the absence of pre-existing session information.