AP1252-AG with Cat 3560 / Cat 3750

Question

Hi All,
please advise, I am probably not the only one, but I have come to realise that 15.4W provided by switch ports on 3560/3570 catalysts is not sufficient to power up an AP1252-AG dual radio device. I have read the spec and it says that a dual radio AP requires 16.9W, but a single radio AP will consume/need 12.95W plus a little more depending on the ethernet cable length. As a test I physically removed one radio from the AP1252-AG and tried to power it up via poe port on switch. The AP powered up OK with just one radio module installed.
However the AP cannot be installed with one module removed, so my alternatives are to either power the AP with direct power supply or use the Power Injector which will provide enough power to start both radios.
I was wondering whether it is possible to have both radios installed 2.4/5.0 Ghz but have one disabled through the software, so that the AP will only effectively be running with one Radio Module (UP), but it will have two Radios installed physically.
I have tried this numerous times, when I try to use poe for the ap, it negotiates with the switch port that it need more power for the two radios, the switch can't provide it so it goes into low power mode.
I was hoping that by disabling one radio and then booting the AP it would only request enough power to feed 1 radio, the switch would be able to provide the requested amount and then the AP would work. But I cannot get this to work, Is it at all possible?

Answer 1

Well yes, if the clients are in range of the same AP, they will use the AP to communicate with one another. But if you have several APs, say one AP in one room and another AP in another room, then usually signal travels from wireless client 1 to AP 1 via the radio, then AP 1 forwards the packet over a cable to a switch that relays to the second AP, then the second AP relays the signal wirelessly to the second client. This system is used because usually APs would not use their radio to talk to each other, for many reasons.
In your case, if you have a controller, Aps need to talk to the controller, and the controller doesn't have any radio anyway, so you need cables to connect to your controller. If it is a 2100 controller, you can forget the switch and connect your APs to the controller.
If you have a 4400 series, you need a switch as APs cannot connect directly to 4400 controllers.
Cheers
Jerome