MG Powering Options with MX

[mrush]

Hi,

For the MG, what are some of the recommended powering options when pairing an MG with an MX? Can I use one MG port connected to a PoE switch, and the second port to the WAN port on the MX?

Thanks,

[CptnCrnch · Accepted solution]

No, Ethernet1 / WAN has to be the PoE port. So either you‘ll have

a) an MX with PoE ports

b) connect everything to a PoE switch (via dedicated VLAN possibly)

c) use a PoE injector

d) use a dedicated power supply for the MG

[PhilipDAth]

If I recall correctly, the MG21 has two Ethernet ports.  You can configure one for data and the other for PoE only.

If you configured the port for PoE only you could plug it into an PoE port on an MX.

A power injector does seem rather simple though ...

[NolanHerring]

Maybe its just me but I find it ironic that the big MX models (MX84 and above) do not have any PoE ports =(

[espenvp]

I've recently deployed a fair ammount of MG21E's along with the MX68.

Thankfully the MX68 comes with two built-in PoE ports, however the MG's naturally would like to be connected to the WAN1/2 ports. Hence their mode of operation 😉 But at the current state of things - thats not so easy.

So I came up with the following workaround/solution:

MG port1 - MX port 11 (for PoE)

MG port2 - MX port wan1 (for uplink)

MX port 11 is configured as a trunk, under native VLAN "drop untagged traffic", allowed vlan: you need to add something. With this port11 provides PoE power to the MG, but the MG linknet comes nowhere.

The actual wan connection is done over  MX wan1 and MG port2.

Works for now, but I've issued a "feature request" for moving wan1 and wan2 to the PoE ports on the MX68 (and similar models).

I've also deployed two MGs (multiple carriers) on one MX using the same method and that also works. Using MX wan2 and port 12.

[shauno]

Thanks for the detail on how to configure the MX PoE port - this should be in the doco as a use case!

[Arun_Paul]

MX85, MX95, and MX105 models have PoE+ capable WAN links that would help you connect your MG directly --- without a PoE injector.

Thanks,

Arun Paul

[NolanHerring]

So I'm discovering now that the LAN ports on MG51, when connected to two MX85 WAN ports, only one port gets PoE. So if FW1 dies, and its the one providing PoE to the MG51, the second connection (which is up) to FW2 doesn't have PoE, so the MG51 goes down. 

Any way to get dual-PoE from the WAN ports to both LAN ports on the MG51?  So there is no outage created.

[NolanHerring]

Confirmed on another thread by another Meraki employee (and a case I opened) that MG unit only support a single PoE source at a time. Data can be dual, but not PoE.

[Arun_Paul]

The new MG52 series of Cellular Gateways support PoE on both LAN ports.

From our documentation - "The port labeled “PoE” (Port 1 & 2) accepts 802.3at power."

Meraki documentation - MG52E installation guide

[NolanHerring]

Hi @Arun_Paul !

Are you saying that the new MG52 (which I didn't know existed lol) is able to have PoE active on both ports at the same time? The documentation you linked basically matches the MG51 documentation regarding PoE, so I'm not seeing anything specifically calling out any PoE difference.

To reiterated, both LAN ports CAN accept PoE, but on the MG51, only one at a time. I have it connected on both ports to warm-spare MX85 and if the MX that happens to be providing power, reboots or loses power, then the MG51 loses power and reboots on the other port connected to the other MX85.

If the MG52 allows dual-PoE active, that would be nice.

[MattF]

I have the same question please @Arun_Paul, and also...

I noticed that the MG41/41E, 51/51E and 52/52E Technical Specifications docs at https://documentation.meraki.com/MG/MG_Datasheets all contain the following statement, but the MG21/21E doc doesn't.   Can you confirm if the same applies to the MG21/21E? - 

Power Adapter vs PoE : The MG can be powered using a PoE or via a power adapter. The power adapter always takes the first preference i.e if the MG is already powered via the PoE and then the power adapter is connected, then the MG will power off and power on using the adapter as the power source. The same scenario applies when the PoE and power adapter are connected simultaneously and the power source from the adapter goes down, the MG will power off and then power on. Plugging/unplugging PoE when power adapter is connected to the MG does not have any bearing on the operation of the MG as the device will always draw power from the adapter whenever it is connected.

[Arun_Paul]

Its the same behavior on changing from PoE to power adapter on MG21 series as well.