This carries the remote peer IP address of the primary pseudowire referenced in a protection-related notification, letting the admin identify which far-end router terminates the working PW that this protection event concerns. This is useful when investigating whether a protection switchover was triggered by a problem specifically at that remote peer, since it points directly to which remote device to check. If that peer address is found to be unreachable at the time of the trap, that's a strong indicator of what caused the primary PW to fail over to backup in the first place.