USB Modem Support in MX 19

[Steveruno]

Is the USB modem support code still in MX 19.1 or has it been removed?  I tried a ticket with Cisco/Meraki support and they finally came back and said they did not know and quoted the generic language about lack of support in MX 18 and later.

In my situation I have needed the USB modem twice in MX 18 to reboot the MX after the DHCP processes quit working causing  both WAN and LAN clients to fail as their leases expired.  My educated guess is that if the USB modem code is still in MX 19 then my USB modem would continue to work as it worked in MX 18.

[alemabrahao]

USB modems with MX/Z series devices running firmware MX 18 or newer will be limited to best effort support and will not be receiving any future firmware fixes or improvements. 

https://documentation.meraki.com/MX/Cellular/3G%2F%2F4G_Cellular_Failover_with_USB_Modems

[alemabrahao]

Security appliance firmware versions MX 19.1.8 changelog

Important notice

• As of MX 19.1, Cisco Meraki will no longer support USB-based Cellular Failover on the MX and Z platforms.

New MX 19.1.8 stable release candidate: more fixes than Bob the builder - The Meraki Community

[Steveruno]

I am looking for someone that knows the answer to question.  You are doing what the TAC did and citing notes that have the wishy-washy wording to them.

[alemabrahao]

Because this is the answer. 😉

It was not removed (yet), but it's limited.

[PhilipDAth]

We've changed over to using the MX67C for new purchases.

The USB modem support was starting to get a bit flaky.

[Steveruno]

My thought was that if the code is still there and the modem has been working then it will probably stay working until the code goes away - at least for my purpose of remote reboots.  Just trying to get a straight answer on that and nobody really seems to know one way or the other?

[PhilipDAth]

We have not found that to be the case.  Since that code is no longer tested, we have found MX versions that are broken with some of the USB modems we were using.  Other USB modems work fine.

It has reached the point where we can be confident that our USB modems will definately work during a failover.  Some definately still do work - but not all.

[Steveruno]

I realized I was overthinking this.  I have backup WAN through 5G and the only thing I use the USB modem for is remote reboot when the DHCP fails in the Meraki.  The two failures I have had "USB Failover" would not matter as the client are losing their IP addresses as well as the WAN so there is nothing to failover when this happens.  I am guessing maybe the USB modem gets the IP address rather than the Meraki so that is why is why it still works?  IN any event as long as Meraki allows the interface to be reachable from the dashboard then it will work for my purpose.

[ConnorL · Accepted solution]

Hey @Steveruno 👋🏻 

The ability to use a USB Cellular modem is still present in MX 19.X, it will be fully removed in MX 20.

Using USB Cellular modems in MX 19.X may work, however the last official supported release was MX 18.2.

If you're experiencing issues with USB modems on MX 19.X, I would advise rolling back to MX 18.2. Support for this feature will no longer be provided should you experience any issues.

I would advise looking into alternative solutions such as the MX-C or MG series. 

[Steveruno]

Thanks this is the answer I was looking for.  Assuming I have no DHCP system failures in MX 19 I can probably let the USB modem go when it is time to go to MX 20...assuming MX 20 even runs on an MX-68?

[PhilipDAth]

Would it be fair to say that 18.2 engineering support for 18.2 has ended?

Is 18.2 actually still a currently supported release?

[ConnorL]

The end of support date for MX 18.2 was August 20th 2025. It was the last supported release for USB Cellular modems. So I'd only advise rolling back to this build should you face USB modem issues after upgrading to MX 19 whilst you explore an alternative cellular solution.