ISO/IEC 14908-4:2011 specifies the transporting of the Control Network Protocol (CNP) packets for commercial local area control networks over Internet Protocol (IP) networks using a tunnelling mechanism wherein the CNP packets are encapsulated within IP packets. It applies to both CNP nodes and CNP routers.
The purpose of ISO/IEC 14908-4:2011 is to ensure interoperability between various CNP devices that wish to use IP networks to communicate using the CNP.