Connecting 2.5gbe and 5gbe Devices to a 10gbe Network

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Apr 30, 2016
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My question is: how should I connect my 2.5 GBE and 5 GBE devices (such as my router and access points) to my 10 GBE home network? I notice that there are 2.5 GBE PoE+ switches available that cost into the thousands of dollars. This seems absurd. What are the alternatives?

Specifically, I am unsure about the interfaces marked in red in my UML diagram below.

1.) Connecting a new Wi-Fi 6e Access Point to my Dell Power connect Switches, or to my network in general. Is there any really high end 6e AP that has anything but a 2.5 poe + interface?
2.) Connecting my multi gigabit At&t fiber gateway to my network.

It seems like almost every home lab would have a problem like this, and as mentioned earlier by @jgreco, the marketplace for multi gig networking equipment is a mess.




home.network.png


Specifics:
At the heart of my home network are:

1 x Dell Powerconnect 8024f 10gbe Switch
1 x Dell Powerconnect 5524 10gbe Switch

I have At&t Fiber at my house
1 x AT&T Fiber Gateway (model: bgw320-500) with a 5gbe RJ-45 WAN port

I have purchased an old SFF PC and installed PfSense on it for my router. I chose it from the known good hardware list for pfsense, and it said it was reverse compatible with 2.5gib and 5gib. Fingers crossed.
1 x HP S01-pF2016 Slim Desktop

And I just ordered an Intel NIC that I hope is backward compatible with both my At&t Fiber Gateway, and my Dell Powerconnect switch
1 x Intel X550-T2 Dual Port 10Gb Base-T Adapter
 
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Etorix

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With a NBase-T transceiver in the SFP+ switch for the 2.5 GbE link to the access point. I'm less sure how you get PoE+ in there with 2.5 GbE though.
The rest looks good. The 50ft 5e cable is unfortunate because a long run is where optics would excell, but I suppose there's no easy way to replace it without breaking the wall.
 
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With a NBase-T transceiver in the SFP+ switch for the 2.5 GbE link to the access point. I'm less sure how you get PoE+ in there with 2.5 GbE though.
The rest looks good. The 50ft 5e cable is unfortunate because a long run is where optics would excell, but I suppose there's no easy way to replace it without breaking the wall.

If they made a SFP+ transceiver that worked with any new 6e access point and it's PoE, that would be wonderful!

I shopped around for a while and thoroughly confused myself trying to decide which one would work. Thanks for the guide. But I agree, I don't see any that offer PoE. :(
 

Etorix

Wizard
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You will NOT get PoE from an optical transceiver because the physical interface is not designed to supply this amount of power.
PoE will have to be injected, but PoE was designed for 1 GbE and is not part of the later 2.5 or 5 GbE standards. So you'll need to find a PoE injector which goes above the specs and works while passing a 2.5 GbE signal.
Or power the access point from another source.
Or live with a 1 GbE link to the access point.
 
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jgreco

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PoE was designed for 1 GbE and is not part of the later 2.5 or 5 GbE standards.

Sorry, @Etorix , but this is incorrect. PoE is not supported at 10GBase-T, which will eventually be the demise of 10GBase-T when a "new" 10GBase-T standard is released for PoE when there's a crapton of 10GBase-T stuff out there that is incapable of coping with it.

Note that the compelling motivation manufacturers have put out for 2.5 and 5GBase-T is that the standard was written to accommodate wifi access points, especially WiFi 6E ones, for PoE needs.

It used to be that we upgraded an order of magnitude at a time. We had 10Mbps in 1993, 100Mbps in 1996, 1Gbps in 1999, and 10Gbps in 2002. About a three year cadence. Then TWENTY YEARS passed, and we have been handed 2.5Gbps and are being told to be thankful for this meager downgrade. The switch manufacturers used to have to work for their money; now they are having a field day selling 2.5Gbps to replace 1Gbps equipment sold YEARS ago. And many suckers are buying into it. The only ones who might credibly have a NEED for 2.5Gbps are the people stringing up PoE AP's; everyone else should really be doing 10Gbps, but their failure to do so means that there will be another forklift upgrade in just a few years to get to 5Gbps, and then again to 10Gbps. I find this disgusting and wasteful.
 

Etorix

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Fine! I don't mind standing corrected for a good cause. So the OP should be able to find a 2.5 GbE-capable PoE+ injector and get everything as intended. But no PoE+ from a SFP+ switch, right?
 

jgreco

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So the OP should be able to find a 2.5 GbE-capable PoE+ injector

I've never seen a 2.5GbE PoE+ injector but then again I guess I haven't had reason to look. It appears that UI and Trend both offer them though.


Wow what a hunk of metal. Usually what you want is to buy a switch that has it natively; injectors basically suck unless you only need one or maybe two.

But no PoE+ from a SFP+ switch, right?

That's correct. Here's why.

Classic 802.11af allows 15 watts; enough to power a basic IP camera, access point, or basic desk phones.

PoE+ 802.11at allows 30 watts; enough for some integrated-IR illumination IP cameras, heavier duty access points, or fancy phones.

PoE++ 802.11bt allows 60 watts; enough for most fancier cameras, and most 802.11ac access points.

PoH 802.11bt allows 90-95 watts and is aimed at access points. It was designed into the 2.5GBase-T and 5GBase-T standards as people could see the writing on the wall.

Now I've outlined this in this manner to give you a high quality answer, your reward for gracefully accepting correction. ;-) The point is that an SFP+ module in a standard switch only has a power budget of 2.5 watts for the module, at maximum, and so you just don't have any spare watts to provide PoE. If you look at the fine connector traces on an SFP+'s PCB edge connector, it should be clear that none of them are going to sustain more than a trickle of current.
 
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