Question: What are the implications when an SMR (Short Message Relay) entity sends an MNSMS-ESTablish-REQuest to transmit a RPDU (Radio Protocol Data Unit) on the mobile radio interface?
Option 1: Establishment of a CM-connection, formation of a CP-DATA message containing the RPDU, and passing of CP-DATA to the MM-sublayer for the requesting SMR entity.
Option 2: Immediate transmission of the RPDU over the existing signaling connection without forming a new CP-DATA message.
Option 3: Release of any existing CM-connection to prioritize the establishment of a new MM-sublayer connection for the SMR entity.
Option 4: Direct forwarding of the RPDU to the UE (User Equipment) without involving the MM-sublayer.
Explanation: The correct answer, Option 1, highlights the three key implications of an MNSMS-ESTablish-REQuest for transmitting a RPDU as per the 3GPP specification. This includes setting up a Connection Management (CM) connection specifically for this Short Message Relay entity, creating a Control Plane (CP)-DATA message that encapsulates the RPDU, and then forwarding this CP-DATA to the Mobility Management (MM) sublayer for further processing. This process ensures structured and managed transmission of short messages over the mobile radio interface, emphasizing the importance of connection establishment, data formatting, and inter-layer communication in telecom networks.