Hi Everyone,
@JasonCampbell, @jdsilva, @PhilipDAth @MoBrad
I manage our documentation. Hopefully I can clarify a few things here. First:
@GreenMan wrote:
Whilst it's not related to the cabling, please note that, at this point in time, the new MX67 and MX68 models do not yet support VRRP (i.e. warm standby).
This is not correct. MX Cellular models DO support VRRP/warm standby, just not using cellular. You can absolutely set up MX Cellular models in an HA pair configuration, we just recommend doing so without LTE.
This is what your recommended failover options look like:
On the left, you can use MX Cellular models just like any other MX model in a standard HA pair. The left-side design is the recommended HA design for ALL MX models. Notice that the topology matches the documentation. The design on willette.works is not an official Meraki design and is not recommended.
So you might be thinking: "The design on the left is using cellular MX models but isn't using LTE failover at all. What's the point in using cellular models?" - If your priority is HA failover, you may not want to use an MX Cellular model. If your priority is LTE failover, we recommend the design on the right side. If you happen to have an MX Cellular model on hand and WANT to do HA failover, the design on the left side is officially supported and recommended.
The design on the right side is how we officially recommend using LTE failover. On a single MX Cellular device, not in an HA pair.
Alright so, the next question is: "Alright, well what would happen if I DID set up LTE in an HA pair?"
This is answered in the HA documentation, as @NolanHerring pointed out.
Cellular Failover Behavior
Meraki does not currently support any cellular failover with a high availability (HA) pair; as we do not perform connection monitoring on cellular uplinks (as of MX 10.X+), which is necessary for HA uplink failover. At this time, if a cellular uplink is used in an HA pair, the following will occur in order:
Primary MX WAN 1+2 fails > fails over to Secondary MX
Secondary MX WAN 1+2 fails > fails over to Primary MX Cellular
Primary MX cellular fails > fails over to Secondary MX Cellular
What does that actually look like? Here's a diagram to clarify:
This diagram shows what happens when you use LTE in an HA pair. Note the RED TEXT at the top saying that this isn't officially supported or recommended. This is just to clarify current device behavior.
Cheers.
Cameron Moody | Product Manager, Cisco Meraki