Access point without enough power

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Oct 27th, 2009
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My AIR-LAP1252G-E-K9 access point doesn't register against the controller. The switch is seeing both the MAC and the IP of the AP, but the power inline seems not to be enough. Although the switch sees the AP's IP address by CDP, this one doesn't answer the ping request.

Device ID: SFJ2AP2

Entry address(es):

IP address:

Platform: cisco AIR-LAP1252G-E-K9 , Capabilities: Trans-Bridge IGMP

Interface: GigabitEthernet1/0/7, Port ID (outgoing port): GigabitEthernet0

Holdtime : 125 sec

Version :

Cisco IOS Software, C1250 Software (C1250-K9W7-M), Version 12.4(10b)JA3, RELEASE SOFTWARE (fc1)

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Compiled Wed 19-Mar-08 18:56 by prod_rel_team

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Duplex: full

Power drawn: 11.000 Watts

Power request id: 63976, Power management id: 2

Power request levels are:11000 0 0 0 0

Management address(es):

Is this a hardware problem? What could be the source of it?

Thanks in advanced for your ideas!

Best regards,


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Rob Huffman Tue, 10/27/2009 - 10:00
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Hi Laura,

Yes, it's most cetainly a "PoE" problem;

Powering the Aironet 1250 Series Access Point with 802.3af Power over Ethernet

The Aironet 1250 Series Access Point with one RM1252 radio module installed requires 12.95W, which is within the 802.3af Power over Ethernet (PoE) standard. Any Cisco switch supporting 802.3af may be used to power the Aironet 1250 Series Access Point with one RM1252 radio module installed. This is ideal for businesses that chose to only deploy on a single frequency (2.4 GHz or 5 GHz). A single radio provides optimum performance with approximately 300 Mbps maximum PHY data rate. Customers who deploy dual-band, 802.11n radios and power the 1250 Series using standard 802.3af will have more reliable and predictable coverage than that provided by traditional 802.11a/g networks; however, operation will be limited to a single transmitter per radio with maximum PHY data rates of 150 Mbps instead of 300 Mbps per radio. Customers with a significant investment in 802.11 a/b/g client devices that have low-to-medium bandwidth needs but high-reliability requirements will benefit the most from this type of deployment scenario.

Powering the Aironet 1250 Series Access Point with Cisco Enhanced PoE

Cisco Enhanced PoE was designed for customers who want to install new PoE-enabled technologies that require greater than 15.4W per port to function at full capability, such as wireless technology based on the IEEE 802.11n standard. Cisco Enhanced PoE provides the full power requirements for dual-radio modules and eliminates the need to run an additional cabling drop or insert a separate power injector. Support for Enhanced PoE is currently available on a variety of Cisco Catalyst® switching platforms. For more information on Enhanced PoE, visit

What are you using for the 1252's?? If you are using an "E" Series 3750 this is a very good thread; - Mobility&topic=General&topicID=.ee6e8b8&fromOutline=&CommCmd=MB?cmd=display_location&location=.2cc039db

Hope this helps!


Leo Laohoo Tue, 10/27/2009 - 14:33
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Hi Laura,

What is the firmware of your WLC? Latest version of the 5.X and 6.X now supports the 1250 operating at PoE (15.4 watts) with both radios enabled BUT at a cost of lower MCS rates.

For autonomous IOS, 12.4(10b)JDA3 and later, is the same version.

Both versions will upgrade the radio modules' firmware to 2.00.22. Later version will bring the firmware to 2.10.19.

Hope this helps.


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