Question: Which of the following accurately describes the primary purpose and direction of communication on the SLg interface in a telecom network?
Option 1: Bi-directional, where the GMLC sends location requests to the MME for a target UE, and the MME returns location results to the GMLC.
Option 2: Uni-directional, from the MME to the GMLC, primarily for sending location updates of all UEs in the network.
Option 3: Uni-directional, from the GMLC to the MME, solely for requesting locations without receiving any response or results.
Option 4: Used between two GMLCs for sharing location data of UEs across different networks.
Explanation: The correct answer is Option 1 because it accurately reflects the bi-directional nature of the SLg interface, as defined by its use for both sending location requests from the Gateway Mobile Location Centre (GMLC) to the Mobility Management Entity (MME) for a specific User Equipment (UE), and for returning the location results from the MME back to the GMLC. This bi-directional communication is crucial for the efficient management of Location Services (LCS) in telecom networks, ensuring that requests are met with responses to facilitate various location-based services.