Aironet 1562i on 802.3at PoE?

[acrosby.rigstar]

Hi - We are installing some customer-provided 1562i access points into their existing network, and they are planning to power them via Catalyst 2690-S switches, which offer PoE+ output. However, I see that the hardware documentation says that the omnidirectional access point will operate in 2x2 radio mode rather than 3x3 if powered by PoE+ instead of UPoE.

What is the practical outcome of this? I assume that coverage would be reduced to approximately a 240-degree arc rather than 360 coverage - if so, how should the access point be oriented to get coverage in the desired directions? Would the signal range be reduced as well?

Appreciate any input on this matter.

Cheers,

- Alex

[Leo Laohoo]

The AP requires, a minimum of, 25.0w PoE.  Ideal/Recommended PoE requirement of 39.0w. 

A plain 2960 can only support up to 15.4w PoE.  This amount is not enough and the radios will not work and the AP will not join any controller. 

Use a power injector instead.

[acrosby.rigstar]

Hi Leo,

Thank you for the reply. To clarify, it is a 2960-S switch, which should be able to provide up to 30W of power and is PoE+ compliant. I'm trying to figure out what exactly the difference in behaviour is between the minimum power requirement and the recommended power, since the Aironet AP spec sheet says it will still operate in 2x2 mode at the lower power level. I'll update the original post to reflect this info.

The client is supplying the equipment for this job, so we're working with what we have unless a power injector is absolutely necessary.

Cheers,

- Alex

[Leo Laohoo]

I initially read the thread as "2960".  
2960S will have enough power for the AP to operate in "low power" but still works.  I have more than 50 of the 1562i powered up with 2960S without any issues.

[acrosby.rigstar]

Yes, I've figured out that much from the specs, I'm more wondering about the practical difference operating in low power vs full power - is it a matter of range, coverage, or both? This is for an outdoor application, so it's definitely a matter of interest on this project.

[Leo Laohoo]

It is more the Tx power get curtailed.

[Arshad Safrulla]

With POE af (15w) all the radios will be shutdown, but AP will join the WLC, can confirm this as we use a POE switch to stage the 1562's before deploying. Also POE bt (60w) reqd only for internal antenna model (1562i), POE at (30w) is sufficient to power the 1562e with full functionality. Also from our internal test's in E regulatory domain, we haven't seen any TX power reduction when connected to POE at switches. 

Also from all the Cisco documentation it always says access point will automatically disable one of the 2.4 GHz and 5GHz transmitters and the radios will operate in 2x2 MIMO mode. But as @Leo Laohoo highlighted, some regulatory domains which allows high transmit power may get effected.