Cellular restrictions with warm spare on MX67C / MX68CW

[CptnCrnch]

Just had a look at the 15.18 Beta changelog and stumbled upon this:

• When deployed in warm spare / high availability (HA), MX67C and MX68CW do not support using their cellular connectivity to pass client traffic. In this deployment, the cellular connectivity can only be used for device monitoring or network troubleshooting. This is an expected limitation for these platforms

In a nutshell: in case an MX67C is deployed in a warm spare environment, cellular backup is utterly useless and even expected behavior? Is this an „end of the line“-statement or will the „expectation“ possibly change someday?

This kind of setup poses a „last resort config“ for many customers. They would like to provide hardware HA and just in case everything else regarding wired connectivity fails, it‘s just natural to have (at least) an LTE fallback option. What‘s the reason to deploying these kind of devices then if such a crucial feature is missing because it‘s „expected behavior“?

My question therefore is: is it going to stay this way or are we going to see both features (HA and cellular backup) in 15.x somewhen? 

[ww]

its already for a long time in the change logs. i dont know if this is correct... why would it work in standalone but not in warm spare...   did someone test this?

[NolanHerring]

I have two MX67C in warm spare. Primary with Verizon, Secondary with AT&T and I've tested fail-over and they work, pass traffic. Just recently had WAN1 go down at a site, and the cellular kicked in just fine on the Primary.

Running 14.39 though, so I'm not sure if the 'issue' is introduced in 15.X train. If it is then I'm stay the hell away.

The whole point of the built-in cellular is for redundancy, along with warm-spare. This seems like a major flaw in my eyes.

[CptnCrnch]

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The whole point of the built-in cellular is for redundancy, along with warm-spare. This seems like a major flaw in my eyes.

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Exactly that's what it is. What's the point in having a setup that's as highly available when the "last line of defense" won't work anyways?

I'd be more than grateful if the Meraki folks could clarify this. 😬

[Seshu]

Hello @CptnCrnch 

The Cellular Failover in an HA Scenario is not officially supported by Meraki as there are Certain Connection Monitoring restrictions over Cellular. It, however, may work in the following order of failovers - https://documentation.meraki.com/MX/Deployment_Guides/MX_Warm_Spare_-_High_Availability_Pair#Cellula...

1. Primary MX WAN 1+2 fails > fails over to Secondary MX
2. Secondary MX WAN 1+2 fails > fails over to Primary MX Cellular
3. Primary MX cellular fails > fails over to Secondary MX Cellular

This is the most up-to-date KB on the expected behavior of Cellular on an HA pair. I would recommend submitting a feature request from the dashboard using the "Make a Wish" button since this is currently the expected behavior. Feel free to let me know or reach out to support@meraki.com if you have any questions. 

Regards,

Meraki Team