Question: In a network sharing scenario with shared signalling transport, how is an interface instance identified for non-UE associated signalling on the Xn-C interface?
Option 1: By assigning a unique UE XnAP ID
Option 2: Through the use of a dedicated F1-C Transaction ID
Option 3: By incorporating a Cell ID in the message header
Option 4: By including an Interface Instance Indication in the respective message with an assigned value
Explanation: In network sharing scenarios where multiple cell IDs are broadcast with shared signalling transport, identifying interface instances for non-UE associated signalling requires a mechanism that doesn't rely on UE-specific identifiers. On the Xn-C interface, this is achieved by including an Interface Instance Indication within the message and assigning it an appropriate value, ensuring clear identification of the interface instance involved in the signalling exchange.