Question: What action should the initiating node take if it receives an EN-DC X2 SETUP REQUEST from a peer entity on the same X2 interface, responds with an EN-DC X2 SETUP FAILURE, but then receives an EN-DC X2 SETUP RESPONSE?
Option 1: Reinitiate the EN-DC X2 Setup procedure immediately towards the same peer node.
Option 2: Ignore the EN-DC X2 SETUP RESPONSE message and consider the X2 interface as non-operational.
Option 3: Send another EN-DC X2 SETUP FAILURE message to confirm the failure.
Option 4: Wait for a predefined time before responding with another EN-DC X2 SETUP FAILURE.
Explanation: If the initiating node responds to an EN-DC X2 SETUP REQUEST with an EN-DC X2 SETUP FAILURE but then receives an EN-DC X2 SETUP RESPONSE, it should ignore this response and mark the X2 interface as non-operational. This ensures consistency in error handling and interface status management.