Question: In the context of the SGs interface, who includes the MME Name information element when sending a message to the other entity?
Option 1: Mobility Management Entity (MME) when sending to Visitor Location Register (VLR)
Option 2: Visitor Location Register (VLR) when sending to Mobility Management Entity (MME)
Option 3: Both MME and VLR include it regardless of the direction
Option 4: Neither MME nor VLR includes this information element
Explanation: According to the specification, when the Mobility Management Entity (MME) is the entity initiating the communication (i.e., sending), it must identify itself by including its MME Name in the message sent to the Visitor Location Register (VLR). Conversely, if the VLR initiates the communication, it does not include the MME Name information element. This highlights the importance of clear identification in network signaling for efficient and accurate communication between different network entities.