Host Engineering Forum

General Category => Do-more CPUs and Do-more Designer Software => Topic started by: belias on February 13, 2022, 12:48:07 PM

Title: Wireshark showing ICMPs from BRX to Ruckus WiFi Access Point?
Post by: belias on February 13, 2022, 12:48:07 PM

I'm troubleshooting an issue with some Stride I/O modules where the ethernet port on those devices is occasionally unable to pass traffic after bootup on my network.  It happens about 50% of the time, so it's been fairly easy to troubleshoot.

I think I've isolated the problem to being related to a Ruckus Wireless Access point on the same LAN.  Whenever I disconnect this device, the Stride units boot up properly.  The network has quite a few other devices on it, including 3 BRX PLCs.

In the course of troubleshooting, I was reviewing Wireshark captures and noticed that there's periodic ICMP traffic initiated by 2 of the BRX PLCs to the WiFi access point, and I can't figure out what's causing this.  The 2 BRX units have a very basic setup and are mainly in place as slave devices using PeerLink to transfer data back to the master PLC.

See attached pic for a screenshot of the Wireshark capture.  The PCAP is here: https://www.dropbox.com/s/frrubass43q2ok0/BRX%20Wireshark.pcapng?dl=0

Any ideas?


Thanks.

Title: Re: Wireshark showing ICMPs from BRX to Ruckus WiFi Access Point?
Post by: BobO on February 14, 2022, 10:06:45 AM

The PLCs are responding to packet #9 indicating that they can't route it. They received the packet because it was sent to the subnet broadcast address of their subnet.

Title: Re: Wireshark showing ICMPs from BRX to Ruckus WiFi Access Point?
Post by: belias on February 14, 2022, 02:06:29 PM

Ah ok.  I knew it was sent to the subnet broadcast address, but I didn't realize that would cause a response.  I haven't seen that behavior from other devices...  In any case, it certainly shouldn't be causing any problems.

Thanks for the quick reply as always - much appreciated!