KNX Stack – Medium IP
In the KNX System the Internet Protocol IP is not only used as a fast backbone, it is also defined as a stand-alone medium like TP or RF. KNX devices which use the IP medium are also called ‘KNX IP only devices’.
This technology enables powerful KNX features – like configuration modes and interworking – also on IP. The proven configuration modes of other KNX media are also available for KNX IP devices. KNX IP opens the door to top level communication within a building (e.g. telecommunication, multimedia, etc.) and allows an entirely new class of KNX devices.
Transmission of KNX messages via IP/Ethernet is defined as part of the KNXnet/IP protocol based on UDP (User Datagram Protocol). The use of IP technology enables external connections to the KNX installation via the internet.
The System Software for a KNXnet/IP device indeed consists of two protocol stacks. For the communication over Ethernet an IP stack with UDP is needed, as the KNXnet/IP is based on connectionless communication. Numerous operating systems like Linux or Windows already provide an IP-stack. The KNX stack is put on the IP/UDP stack and uses it as interface to the network. The protocol layers of the OSI/ISO reference model and additionally the particular device model with appropriate management procedures are contained in the KNX stack.