Wireless Access

It's my understanding that 802.af (15W) PoE isn't sufficient for AP-125s to run in 3x3 MIMO mode.

We have 802.3at complient power injectors running a few AP-125s in high density areas. Is there anyway to confirm that the APs are in fact doing 3x3? I can see some 2 spatial stream clients connected but I don't see any indication of the antenna mode.

The AP-125 will run fine on .af or .at power (full 3x3).  You MIGHT lose the second Ethernet port, but that's the only if you have a long cable run and are running .af power.

To verify this, do "show ap debug system-status ap-name xxx" and look at the "Power Status" section (very close to the end of the output).

The AP-124 and AP-125 have some built-in intelligence to manage power consumption based on what's available from POE. If there's not enough power available to run the AP in full-function mode (power profile 1), the second ethernet port will be disabled (power profile 2). When powering the unit from a marginal 802.3af POE source, using long Ethernet cables, and/or lower quality cables, further reduction of power consumption may be needed, and the AP will change from 3x3 to 2x3 mode (power profile 3; the third transmit chain is switched off). The impact of this on performance is marginal.

Power profile 3 can be supported from any 802.3af POE source, using any cable type and length.

Power profile 2 can be supported in most typical cases using 802.3af

Power profile 1 may be supported from 802.3af, but is guaranteed from POE+ or 802.3at.

So how does one determine which Power Profile my AP is operating in?

From the command line issue the following command.  The output will be long but at the very end will be a section named Power Status.  That is what you are looking for.

"show ap debug system-status ap-name <name>"