I am not able to discover BACnet devices although they are online

Owned by Wolfgang Granzer
Last updated: Nov 07, 2023 by Stefanie Furtak
1 min read

This problem may occur when the BACnet devices and the BACnet clients (e.g. NETx Server) are in different IP networks. BACnet management communication which is used for discovering devices and their objects is based on IP broadcast. Therefore, it is problematic when BACnet clients and BACnet servers are in different LANs since broadcast is normally not forwarded by IP routers.

To solve these issues, BACnet uses so called BBMDs (BACnet Broadcast Management Devices). They are retrieving the request as unicast and forward them to their local LAN as broadcast. A good article that explains the role of BBMDs and their functionality can be found at the BACnet Institute (login account and article is for free).

Our server products support the use of BBMDs. You can define the BBMD info (IP address and port number) within the BACnet driver configuration.

Please keep in mind that BACnet management communication and thus broadcast is only needed during configuration (using the BACnet Explorer). After device discovery, broadcast is not used anymore since normal BACnet runtime communication (reading and writing data, subscribing to objects) is done as unicast communication only.

Article applies to the following products:

  • NETx BMS Platform
  • NETx Multi Protocol Server
  • NETx BMS Server 2.0