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MS108EUP splitters for Non-PoE units?

T35t
Aspirant

MS108EUP splitters for Non-PoE units?

Hi,

I am about to order the MS108EUP, but have a question regarding voltage and splitters. I am planning to use a pair of PoE splitters to power two non-PoE router from the switch. I know that the MS108EUP can output 30W and 60W. But I see no information about the voltage numbers? It becomes a bit of a hassle when I need to take ratings of PoE-splitters into consideration, since I don't want to accidentally "fry" anything.

 

The two units that I want to provide PoE power from the MS108EUP:

* Dedicated firewall router, rated: 12V-4A-48W.

* Router set to AP-mode, rated: 19V - 2.37A / (AC Adapter: 19,5V-2.31A-45W).

 

With these numbers, what ratings on the splitters should I be looking for? The splitters for the firewall seems easy enough to find. But I think that the router AP-router will be giving me a hard time...

Message 1 of 5
schumaku
Guru

Re: MS108EUP splitters for Non-PoE units?

Forget about Thomas Edison's electric Christmas tree light design when it comes to PoE. Thanks to the IEEE standardization, nobody has to worry about voltage on the PSE (Power Source Equipment) side.

 

For your two use cases, the challenge would be to find standard compliant PoE PD (powered devices), which act as smart "power supplies" for the firewall requiring 12V, 4A (48W), and the router with 19V, 2.37A (45W). For the sake of freedom, you can designate this as a power splitter, taking standard compliant PoE power and pin-out on some DC output.  Note this has not much in common with PoE / PoE+ / PoE++ where the PD is directly powering the device, where the PD does notify the PSE about it's power requirements automatically.

 

Some tech data is listed on WikiPedia: Power over Ethernet - however keep in mind there is no Power applied or made available just by plugging a random passive network cable into a PoE port. Before the PSE does provide power, a PD must be connected, informing the PSE about it's requirements, doing a handshake between the PD requirements and the PSE. This is why no overload condition can ever occur, except in the case of hardware design errors, or misconfigured PD or the power splitter in place.

 

Don't know if easy to find such power splitters in the market FWIW. The big challenge is that such a PoE splitter must be able to be customizable in output voltage, and include a power regulator at least. Additional challenges is that the few similar PoE splitters are limited to 1 GbE link speed.

 

The primary aim for this MS108EUP and bigger switch class is to connect and power devices, which understand PoE.

 

Welcome to the Netgear community!

-Kurt

 

 

 

Message 2 of 5
T35t
Aspirant

Re: MS108EUP splitters for Non-PoE units?

Thank you for such a quick response Kurt,

Sounds almost too good to be true. But if it is as you say, if I have 3 possible PoE splitters to choose from, rated the following:

  • 30W, 12V 2.5A
  • 60W, 12V 5A 
  • 90W, 12V 7.5A

Then what you mean is that it doesn't matter which one above I choose from despite the ratings for i.e., the firewall router if I want the MS108EUP to power it using PoE?

 

I noticed that the PoE-splitters out there are limited to 1GbE, which is why I was planning to run PoE and Data on seperate Ethernet cables so i can still utilize 2.5G. I noticed most of the splitters are compliant with 802.3af and 802.3at.

 

I made this diagram to illustrate how I was thinking. The red X on the splitters are replaced with the purple arrows which transmits the 2.5G data, and the PoE on those two ports will not be utilized . Willl the switch be able to power both firewall and AP-mode router properly?
Note: The diagram shows a different splitter. I think that the firewall would be fine, but I am not sure about the AP-router since the voltage of the splitter isn't high enough.

Network2.png

 

Message 3 of 5
schumaku
Guru

Re: MS108EUP splitters for Non-PoE units?


@T35t wrote:

Sounds almost too good to be true. But if it is as you say, if I have 3 possible PoE splitters to choose from, rated the following:

  • 30W, 12V 2.5A
  • 60W, 12V 5A 
  • 90W, 12V 7.5A

The 30W, 12V 2.5A is is to small, so this is out.

 

For a proof of concept, test the config with whatever the firewall requires on the power side. Note: You might have to power it from a 60 W port - as there is not 90 W port on the GS108EUP available, so the 90W, 12V 7.5A is out.

 

Have some manufacturer or vendor URL of these devices at hand? Could be interesting for the community members.

 

@T35t wrote:

Then what you mean is that it doesn't matter which one above I choose from despite the ratings for i.e., the firewall router if I want the MS108EUP to power it using PoE?


This was meant in relation to the two options we talked about before. Looks like the vendor (or the industry) is not ready for a powerful PoE++ like this simple MS108EUP.

 

@T35t wrote:

I noticed that the PoE-splitters out there are limited to 1GbE, which is why I was planning to run PoE and Data on seperate Ethernet cables so i can still utilize 2.5G. I noticed most of the splitters are compliant with 802.3af and 802.3at.


geee, this would make it a show stopper. These injector obviously leave industry standards out of mind, completely mis-balanced products. If they talk about 30W and 60W injectors, I would expect full bandwidth support, not cheap 802.3af and 802.3at. 

 

More of these models for the scratch list. Not ready for a 2023 PoE++ project in my opinion. Sorry for destroying the illusion. .

 

@T35t wrote:

I think that the firewall would be fine, but I am not sure about the AP-router since the voltage of the splitter isn't high enough.


If these power injectors can't offer the required nominal voltage, this is a no-go.

For the firewall, if powering over a network cable is an absolute must OK.

 

Considering there are great powerful WiFi 6 dual-band and Wifi 6E tri-band PoE++ AP readily available in the market, it's definitively to build such a resource wasting design (dual network cabling through the house, two expensive PoE++ 2.5 GbE port is a more than just a little bit shocking to me. Unless you are a system or hardware vendor and want to show off some proof of concept, oh well....

Message 4 of 5
T35t
Aspirant

Re: MS108EUP splitters for Non-PoE units?

Yeah, I misunderstood your earlier comments. I am hoping the PoE splitters (not injectors) will come a longer way in 2023, not being limited to 1GbE. I'll replace the AP router with a PoE AP. Will be a lot less cable clutter and adapters😵. So I will order the switch and the splitter (60W, 12V, 5A) and look for a solid 2.5G AP with PoE.

 

The current AP Router is Asus rt-ax86u, and the firewall is from TLSense running OPNsense.

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