Wireshark is a fantastic tool for network diagnostics. It’s been the best tool for BACnet/IP network troubleshooting for years. It’s even been able to dissect MS/TP traffic dumps if you knew how, and had the right tools. Check out the new Wireshark BACnet MS/TP capture tool, included in 2.4.4 (and possibly earlier), which includes those tools out of the box!

Not sure what I’m talking about here? Check out the BACnet FAQ!

 MS/TP capture tool screengrab from Wireshark

You’ll have to be connected to the BACnet MS/TP network directly. BACnet/IP routers will not work. I’ve used StarTech‘s device successfully and was very happy with it. An MS/TP to IP gateway won’t do the job, since it hides the MS/TP side of things from you.

You can use MS/TP capture with Wireshark to diagnose communication problems. It will also reveal if your token passing is being handled efficiently. Wireshark won’t do any automatic diagnostics for you unfortunately, you’ll have to use your understanding of the protocol to troubleshoot or identify problems. Wireshark does have some handy statistics generating features that can be helpful at a glance, though. It’ll break down the number of packets by the type of message they are sending: Who-Is, I-Am, etc., and what devices are communicating the most.