Is there a bug related to inline power of 3550?

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Mar 28th, 2007
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We are using the inline-power function of some WS-C3550-24PWR-EMI to power on some aironet 1230 APs. There are less than 5 APs on one 3550 usually.

For unknown reason, those 3550s keep shutting down those FE interfaces connected by APs. We can do 'no shut' under the interface to re-enable the AP, however those interfaces will be shut down again after several days. We only see this problem on 3550 so far. Can anybody fell free to tell me what the reason is and how to fix it?



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john.preves Wed, 03/28/2007 - 11:29
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Couldyou post a little more infor regarding the switch config and the AP's.

Are you using the a/b/g radios? This requires 15.4 volts where as the 3550 I think only provides 7.

I'm only guessing right now, but how long has the switch been up, sh run, AP info please

cafershop1 Thu, 03/29/2007 - 12:41
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We are only using b/g. I checked the power level on a 3550 withou this problem, most of APs are using 4.4v.

Those switchs are running for a long time, I think around 2 or 3 years.

On the software side, we just enable inline power by the command of 'power inline auto' on the 3550. The IOS version for APs are 12.3(8)JA2 and switch are 12.1(22)EA8.

On the hardware side, all APs are plug into network jack on the wall and then connect to switches. The distances between APs to switches usually are less than 100 feet.



john.preves Thu, 03/29/2007 - 14:25
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all sounds like this should work.

Is the switchport actually not supplying power, meaning when you find it the AP has no power or is the AP just hung up?

There used to be a firmware issue that periodically choked up the AP. You had to reset the port and it would work for a week or two and then die again.

If there is no power - AP is dead - then you need to call Cisco and start a TAC.

If the AP is hung up you may need to upgrade firmware...


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