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Comment: added more links for BACnet
Revision 7 as of 2007-06-19 17:48:00
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 bacnet || bvlc}}}  bacnet || bvlc || bacapp}}}


BACnet, the ASHRAE building automation and control networking protocol, has been designed specifically to meet the communication needs of building automation and control systems for applications such as heating, ventilating, and air-conditioning control, lighting control, access control, and fire detection systems. The BACnet protocol provides mechanisms by which computerized equipment of arbitrary function may exchange information, regardless of the particular building service it performs. As a result, the BACnet protocol may be used by head-end computers, general-purpose direct digital controllers, and application specific or unitary controllers with equal effect.

The BACnet protocol specifies transport over a number of datalink layers including ARCNET, MS/TP (RS-485), PTP (RS-232), LonTalk, and Ethernet. BACnet also specifies communication over UDP/IP which is known as BACnet/IP. Other datalink layers are proposed.


XXX - add a brief description of BACnet history

Protocol dependencies

  • ["UDP"]: BACnet/IP uses ["UDP"] as its transport protocol. The default UDP port for BACnet traffic is 47808 (0xBAC0), but depending on the project specification other ports are also possible.

Example traffic

XXX - Add example decoded traffic for this protocol here (as plain text or Wireshark screenshot).


The BACnet dissector is fully functional.

Preference Settings

The dissector has no preference settings.

Example capture file

XXX - Add a simple example capture file to the SampleCaptures page and link from here (see below). Keep this file short, it's also a good idea to gzip it to make it even smaller, as Wireshark can open gzipped files automatically.

  • attachment:SampleCaptures/PROTO.pcap

There are some sample BACnet capture files at:

Display Filter

A complete list of BACnet display filter fields can be found in the [ display filter reference]

  • Show only the BACnet based traffic:
     bacnet || bvlc || bacapp

Capture Filter

You cannot directly filter BACnet protocols while capturing. However, if you know the ["TCP"] port used (see above), you can filter on that one.

  • Capture only the BACnet/IP traffic over the default port (47808):
     udp port 47808


Protocols/bacnet (last edited 2012-08-08 00:56:38 by GuyHarris)