Question: In a GSM Public Land Mobile Network (PLMN), what is the primary purpose of the Radio Link Protocol (RLP) at Layer 2, based on LAPB?
Option 1: To manage mobility and handover between different base stations.
Option 2: To prioritize voice traffic over data traffic in congested networks.
Option 3: To implement error control and retransmission mechanisms for reliable data transfer.
Option 4: To encrypt user data for secure transmission across the network.
Explanation: The Radio Link Protocol (RLP) is specifically designed to ensure reliable data transfer by implementing error control and retransmission mechanisms, safeguarding user data integrity, especially in wireless networks prone to signal degradation or interference.