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802.3af v 802.3at - Is 30W enough no matter how you get there?

A model citizen

802.3af v 802.3at - Is 30W enough no matter how you get there?

Hello!

 

Meraki support told me that as long as my APs are powering they are receiving enough power. This turns out to be untrue for many models as @PhilipDAth has written in another post.

 

Oddly, the AR42 pulling 106.9mbit in this image is using an adapter from Cisco that can output 30W. Images:

Screen Shot 2019-07-18 at 5.38.55 AM.png

 

 

The power adapter looks like this:

IMG_2127.jpg

The voltage/amperage math gets us to 30W. Why would this power adapter not provide 802.3at? I swapped it for a PoE+ adapter which does supply at but really this should do it, no? I have also seen a number of adapters with wildly different voltages and amperes where the math works but the ratio is much higher. Any problems there? 

 

Thanks.

Networking geek since high school where I got half of a CCNA. Played Marathon II and Infinity over localtalk.
Made many a network over the years, now de facto admin of a retreat center with some of this fine Meraki hardware.
Fortune 100 Tech veteran/refugee.
3 REPLIES 3
Kind of a big deal

Re: 802.3af v 802.3at - Is 30W enough no matter how you get there?

I don't know the answer.

 

My guess - power supplies are often not dumb power supplies any more.  Often they include a communication protocol.  My guess is the AP asks the AP what it is capable off.  It is expecting to talk to a Meraki power supply.  It doesn't know how to talk to this one, and so instead assumes a safer power budget (802.3af).

A model citizen

Re: 802.3af v 802.3at - Is 30W enough no matter how you get there?

That makes sense. This one is considerably lighter and chintzier feeling than the other one I’m now using. Check out this sample. The MathWorks but this wouldn’t even give POE+ to a MR 30 H.

B461A9CE-EA52-42DC-86D3-CDB7E3B4D345.jpeg

 

Networking geek since high school where I got half of a CCNA. Played Marathon II and Infinity over localtalk.
Made many a network over the years, now de facto admin of a retreat center with some of this fine Meraki hardware.
Fortune 100 Tech veteran/refugee.
Kind of a big deal

Re: 802.3af v 802.3at - Is 30W enough no matter how you get there?

I would avoid using non Meraki power supplies for two reasons.

 

1. You wont get support

 

2. If you manage to fry the device it's not covered by warranty. 

Meraki CMNO, Ruckus WISE, Sonicwall CSSA, Allied Telesis CASE & CAI
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