LoRa packet forwarder on MultiTech gateway not working

We’ve been trying to get a new MultiTech gateway working with chirpstack. We followed all the instructions here: Multitech - ChirpStack open-source LoRaWAN<sup>®</sup> Network Server, set up the configuration files, rebooted it several times. The gateway bridge seems to be running but not the packet forwarder.

It looks like the lora-packet-forwarder starts up, but when using the ps aux | fgrep command, it doesn’t appear to be working.

/etc/openvpn$ /etc/init.d/lora-packet-forwarder-ap1 start
Found MTAC-LORA-H-915 with MTAC-LORA-1.5 hardware at ap1
Starting lora-packet-forwarder: OK
/etc/openvpn$ ps aux | fgrep packet
root 1609 0.0 0.4 3672 1176 ? S 17:01 0:00 fgrep packet

We’ve checked the .json configuration file several times against other MultiTech gateways that we have and it looks correct. We’re feeling stuck about how to further troubleshoot this one.

The gateway is running a recent version of mlinux, converted from AEP.

For clarification, do you have several gateways and those are working fine?

Could you paste the results of this command?

# tail -f /var/log/lora-pkt-fwd-1.log

thanks for the quick response; here is the output:

/etc/openvpn$ tail -f /var/log/lora-pkt-fwd-1.log
tail: can’t open ‘/var/log/lora-pkt-fwd-1.log’: No such file or directory
tail: no files

We have 6 other MultiTech cellular gateways that are set up the same way; all older and all probably running slightly older versions of mlinux and chirpstack gateway bridge

Please note that in the ChirpStack v4 documentation we have updated the Multitech documentation. In the past AEP version there was a lot of magic symlinking happening to make the USB vs SPI MTAC module work (the USB version has been deprecated quite some time ago).

I had a call recently with Multitech about this, their recommendation is to migrate to the mPower firmware, also since they have introduced some new MTAC cards. See also: Multitech - ChirpStack open-source LoRaWAN® Network Server documentation.

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Thank you brocaar! So it sounds like with the newer MultiTech gateway/conduits, we can’t even use an older mlinux firmware to get around this issue.

We converted the firmware from AEP to mlinux. To run mPower, do we need to revert back to AEP?

Thank you brocaar! So it sounds like with the newer MultiTech gateway/conduits, we can’t even use an older mlinux firmware to get around this issue.

“newer Multitech gateway/conduits” is relative :wink: To know which Multitech gateway / conduit works with with mLinux version, it is better to ask this to Multitech directly.

I think there are two things that you could do:

Debug issue on mLinux

What you could do is check the logs. There might be helpful info in /var/log/messages.
As well you could try:

cd /var/config/lora-packet-forwarder-ap1

To see if that prints any helpful information. That is basically what the /etc/init.d/lora-packet-forwarder-ap1 start would do to start the packet-forwarder.

Migrate to mPower

This is recommended by Multitech and this is now covered in the new ChirpStack documentation. In my case, I migrated my Conduit from mLinux to mPower by downloading the mPower firmware image and updating it using the same steps to migrate to or upgrade your mLinux firmware.

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Workaround solution found:
We were able to get Chirpstack to work with mlinux using older versions.

  • mLinux 5.3.31
  • Gateway Bridge 3.9.2
  • OpenVPN 2.4.9
  • Packet Forwarder 4.0.1-r5.0