NBN EN 13321-2:2007

This specification defines the integration of KNX protocol implementations on top of Internet Protocol (IP) networks, called KNXnet/IP. It describes a standard protocol for KNX devices connected to an IP network, called KNXnet/IP devices. The IP network acts as a fast (compared to KNX transmission speed) backbone in KNX installations.
Widespread deployment of data networks using the Internet Protocol (IP) presents an opportunity to expand building control communication beyond the local KNX control bus providing:
Remote configuration
Remote operation (including control and annunciation)
Fast interface from LAN to KNX and vice versa
WAN connection between KNX systems (where an installed KNX system is at least one line)
A KNXnet/IP system contains at least these elements:
one EIB line with up to 64 (255) EIB devices
OR
one KNX segment (KNX-TP1, KNX-TP0, KNX-RF, KNX-PL110, KNX-PL132),
a KNX-to-IP network connection device
(called KNXnet/IP server),
and typically additional
software for remote functions residing on e.g. a workstation
(may be iETS, data base application, BACnet Building Management System, browser, ...).
Figure 1 shows a typical scenario where a KNXnet/IP client (e.g. running ETS) accesses multiple KNX installed systems or KNX subnetworks via an IP network. The KNXnet/IP client may access one or more KNXnet/IP servers at a time. For subnetwork routing server-to-server communication is possible.