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Command priority level in BACNET message


Hi anyone please let me know how to check the priority level in Wireshark?

I need to check the priority level send by two devices, please suggest me the filter and let me know where I can find the priority level in the message?

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asked 19 Oct '11, 14:01

Ravi%20S's gravatar image

Ravi S
accept rate: 0%

edited 20 Oct '11, 07:30

Jaap's gravatar image

Jaap ♦

One Answer:


I know nothing about the BACnet protocol. :)

However, I think if you use Wireshark to open a file containing BACnet frames and look at the dissection of the BACnet frames you should see what you seek. ;)

(Use bacnet as a filter to find the BACnet frames in a capture_).

answered 19 Oct '11, 14:21

Bill%20Meier's gravatar image

Bill Meier ♦♦
accept rate: 17%

Thanks for the info.

I have did it. But the finding priority level is very difficult. If we know the exact filter and how I can identify and where I can identify, that will help me alot

(19 Oct '11, 14:24) Ravi S

As I said, I know nothing about the protocol.

However, I do note that there are some bits in the Control byte of the NPDU level of the BACnet frame that might be what you want.

So: I suggest you look again at a BACnet dissection. :)

If that's not what you want, then I'll not be able to help.


If you click on any particular field (line) in the details (middle) pane of the Wireshark diosplay, you will see the filter (if any) for that field in the bottom status display line in the window in the form bacnet.xxxx.

(19 Oct '11, 14:34) Bill Meier ♦♦