Question: Which of the following PDUs is used for conveying a short message from a Mobile Station (MS) to a Short Message Service Center (SC), as per the SM-TL protocol in cellular networks?
Option 1: SMS-SUBMIT
Option 2: SMS-DELIVER
Option 3: SMS-STATUS-REPORT
Option 4: SMS-COMMAND
Explanation: In the context of Short Message Service (SMS) within cellular networks, the protocol for exchanging messages between a Mobile Station (MS: User Equipment) and a Short Message Service Center (SC) involves specific PDU types for each direction of communication. The SMS-SUBMIT PDU is specifically designated for conveying short messages from the MS to the SC, initiating the message delivery process. This aligns with the fundamental principle of how SMS services operate in telecom networks, where messages are submitted by the user's device (MS) to a service center (SC) for further processing and delivery.