This sets the actual destination IP address that this element uses when transmitting APS protocol messages over IP transport, and like its type companion it can only be configured when cApsConfigMessageTransport is set to 'ip'. Getting this address wrong means APS coordination messages simply never reach the intended far-end peer, effectively breaking automatic protection switching coordination for that group even though the local configuration otherwise looks correct. For example, setting this to 10.20.30.40 means every APS message this element sends for out-of-band coordination goes specifically to that address, and a typo here would silently misdirect protection-switching signaling to the wrong (or a nonexistent) device.