DANSK DS/EN 14908-4 PDF

This European Standard specifies the transporting of Control Network Protocol (CNP) packets over Internet Protocol (IP) networks using a tunnelling mechanism wherein the CNP packets are encapsulated within the IP packets. It applies to both CNP nodes and CNP routers.
The purpose of this European Standard is to insure interoperability between various CNP devices that wish to use IP networks to communicate using the CNP protocol.
The main body of this European Standard is independent of the CNP protocol being transported over the IP network. The reader is directed to Annex A and Annex B for the normative and informative, respectively, aspects of this specification that are specific to EN 14908-1.
Figure 1 shows a possible configuration of such CNP devices and networks connected to an IP network.

Figure 1 Typical CNP/IP application
Figure 1 depicts two types of CNP devices: CNP nodes and CNP routers. It should be noted that the routers shown can route packets between typical CNP channels (such as twisted pair or power line) and an IP channel or it can route CNP packets between two IP channels. In this European Standard the IP channel will be defined in such a way to allow it to be used like any other CNP channel.
In the above diagram the IP network can be considered to be one or more IP channels. This European Standard covers only how CNP packets are transported over IP channels. It does not cover how CNP packets are routed between standard CNP channels and IP channels. This specification is not intended to cover the lower layers (physical, MAC and link layers) of either standard CNP or IP channels.