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WLC - PoE / 802.3af

PoE / 802.3af

The question frequently comes up if APs do support  802.3af standard with non-cisco switch. It happens that radio interface  are power down due to error msg similar to:

Mon Oct 2 17:47:11 2008 AP's Interface:0(802.11b) Operation State  Down: Base Radio MAC:xx:xx:xx:xx:xx:xx Cause=Radio Low Power

It is PoE neg problem with switch.

Action plan:

Turn off the PoE negotiation and try to power on Radio interface.

You only have 2 possibilities to solve this problem.

A.) Disable the CDP on the switch interface connected to AP.

B.) From the controller configure no power negotiation: If you  are using a power injector you will have to make a configuration change  on the controller as follows (e.g check Bug id CSCsc86834 in the Bug Tool )

Depending now on the version you are using please also check Bug  id for commands.

     For version <=3.2.78

          1) configure ap power pre-standard enable <ap-name> where  <ap-name> is the access point name on the controller <show ap  summary>        

          2) configure ap power injector enable <ap-name> <switch  port MAC address in xx:xx:xx:xx:xx:xx format> where <ap-name>  is the access point           name on the controller and <switch port MAC  address> is the MAC address of the switch port to which the access  point is connected)

          After doing those changes, you should see on AP console port:  example

          - power inline negotiation injector xxxx.xxxx.xxxx - power inline  negotiation prestandard source


     For version =>

          After, option override and installed are added to  "config ap power injector"; so that the MAC address of the ethernet  switch is not           required.

Could you please try it? Try first A.) if you are happy with A.)  and it works you don't need to do B.)

Also for your reference about 802.3af / Cisco PoE support using  WLC solution

Table 2 Cisco Access Point Power Capabilities

Cisco Aironet and WLAN Controller Product Power Options

Also for your reference about 802.3af / Cisco PoE support  using IOS (standalone) solution


> power inline negotiation prestandard source
> power inline negotiation injector
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