Good morning all, new member here asking for any info on the RCM3305 rabbit core that is used in a range of iMDUs across our system estate. They’re located in air conditioned rooms down to cabins on hilltop sites.
We’ve been finding that they drop off the network and require a field eng to drive out to push a reset button on the MDU.
I was wondering if there is any legacy faults linked to this item?
The RCM3305 remains operational via serial port but ceases all Ethernet communications. Link detection remains active. Unit does not respond to ARP/ping/HTTP.
Serial console remains responsive and allows IP address changes.
Ethernet functionality returns only after a complete power cycle. Warm restart/software reboot does not reliably restore Ethernet operation.
Problem appears related to elapsed run time and/or Ethernet interface state.
The fault seems independent of temperature, when returned here and taken from the stores to be examined, the MDU shows the Lan and Lan activity leds on / blipping, but the ping ip addr -t commands get no response.
I can change the ip params over the serial port, but theres no response when pinged.
After a few minutes, a power cycle will see it spring into good ping replies.
Is there any problem with stability on these devices?
Additional info, they use a 3.3V supply, not 5V.
They were rolled out into our estate about 20 years ago.
Thanks in advance for any help.
Stewby.
Stewby,
It’s possible that the MDU firmware was compiled with a buggy Ethernet library. There were multiple bug fixes over the history of that library, including different versions of “link recovery” that the chip would go through if the network went down and came back up.
I implemented fixes that went into the August 2020 release of Dynamic C 9.62A. Recompiling the MDU firmware using that release of the compiler could resolve those issues.
Is the MDU manufacturer still in business? Is it possible they released firmware updates at some point that you could install? Do you know if the units have an over-the-air update feature you could use to install new firmware across a network?
A small percentage of RCM3305 products used Softools’ compiler instead of Dynamic C. I’m not familiar with the history of their TCP/IP stack or ASIX Ethernet driver.
Please contact me directly either via the email link on my website, or by emailing my digi.com email address (firstname.lastname for the username). I started using Rabbit products about 25 years ago, worked for Digi from 2008-2014, and have been contracted as the legacy support engineer on the product since 2015. I was able to help another client with patching an ARP-related bug in their deployed Rabbit-based products by two separate vendors. In their case, I extracted binary copies of the existing firmware, identified the broken ARP code sequence, and manually patched the binaries. We were able to use existing over-the-air update procedures to deploy patched binaries and resolve the ARP issue (Rabbit hardware claiming all IP addresses when coming online before the DHCP server).
We can work together to identify the scope of the issue and I can provide an estimate on the cost to implement a solution if the manufacturer isn’t available or able to do so by compiling an updated firmware release.