802.3at Power over ethernet

Unanswered Question
Oct 15th, 2007

we want to replace our old prestandard cat 3524 poe switches, but with the release of the new AP1250 that require 802.3at power we want to hold off until Cisco release an 802.3at switch

anybody any idea when cisco will release such a switch

I have this problem too.
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He's asking about PoE Plus - ieee 802.3at (not .af).

The 1250 doesn't *require* 802.3at. In fact, with 2 radios, it only requires a little more power (~18W) than .af provides. Cisco will be modifying, via software, the max per-port output to satisfy the 1250's requirements. This has been confirmed for the E series cat 3650 and 3750 switches and will probably wind up on the non-E series boxes. We should also see it on the cat 4500 and the cat 6500. The extra output will change your power budget but we'll have to wat for release notes for exact figures.

Hi,

Needing an answer to this question, I went diggin into the specificationf for the 3750 E series switch.

Here is a link:

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750e_3560e/hardware/installation/guide/HIGSPEC.html#wpmkr1037027

Imagine my shock when I noted that the maximum power configuration emits more than 3500 BTUs.

If the 3750G series POE switches are upgradable to "ePOE" or 802.3at, what kind of power consumptions and heating effects will we see for a similar maximum power configuration?

TIA

Charlie

Edison Ortiz Tue, 02/05/2008 - 11:15

The information given on the link you posted are reflecting ePoE option, which is standard on 3750E and 3560E.

HTH,

__

Edison.

Hi Edison,

Thanks for the speedy reply.

So, what is the plan for the switches which I have (3750G-48 PS)? Will they be able to fully power the 1252 APs in 802.11n mode? What will the modification require (software or hardware)? What will the heating effect of these switches be when/if they are powering the 1252 APs in N mode?

Edison Ortiz Tue, 02/05/2008 - 12:51

They won't be able to support ePoE. If you need ePoE, you need to purchase the 'E' model. The battery that comes with those models is very different and actually protrudes in the rear of the chassis.

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Edison.

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