Question: How is an interface instance identified for non-UE associated signalling in case of network sharing with multiple cell IDs broadcast with shared signalling transport?
Option 1: By assigning a unique UE ID on F1-C, Xn-C, and X2-C interfaces.
Option 2: By including the Interface Instance Indication in the respective message and assigning an appropriate value to it on F1-C only.
Option 3: By assigning an appropriate value to the Transaction ID on Xn-C and X2-C interfaces only.
Option 4: By assigning an appropriate value to the Transaction ID on F1-C, and including the Interface Instance Indication in the respective message and assigning an appropriate value to it on Xn-C and X2-C.
Explanation: In case of network sharing with multiple cell IDs broadcast with shared signalling transport, for non-UE associated signalling, the interface instance is identified by assigning an appropriate value to the Transaction ID on F1-C, and including the Interface Instance Indication in the respective message and assigning an appropriate value to it on Xn-C and X2-C. This ensures that each interface instance can be uniquely identified and distinguished from others.