AP230 and the AP390 require 802.3 at power

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We are using PoE from the cisco PoE switch, and power is set to auto on each 230 and 390.
Started troubleshooting one ap that has wifi interfaces up and down, and found it that all AP should have power to be set to 802.3 at manually. Is having power - auto do influences on some access points features or can make wifi interfaces up and down? Thank you
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MST

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Posted 3 years ago

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Dawn Douglass

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We have 230s using PoE from Cisco SG500s.  We are running the latest firmware on the 230s. I have net set any power budget on the switch ports so the APs draw whatever they need.  Is your switch POE+ compliant?  Does the same behavior occur if you plug the AP into a PoE adapter?  

Typically, if a 3x3 AP is not getting enough power it will shut down some of the radios but, not all.

To my knowledge you do not need to set any PoE settings on the switch to manual.  
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MST

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Thank You for the reply. Cisco switches costs a lot of money, especially managed and PoE switched so I believe yes it is PoE complaint. I have 4 access point out of 60 that have all wifi interfaces does up and down all day. And all of them are powered-ed by Cisco switches. I was told by Aerohoive support that all switches needed 802.3 at power. I did the test and tried one of 390 with the PoE injector and same thing. I have the feeling like the either all of 4 APs needs to replaced or their settings needs to be tweaked. 
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Dawn Douglass

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I would upgrade the troublesome APs to the latest firmware and push a complete config.  Then see if problem persists.  If it does, trying plugging one of the bothersome APs into a switch port which is currently serving a working AP.  If the problem does persists, I would ask for an RMA.

One more thing to think about - if you have a lot of POE+ devices in a particular switch the connected PoE devices might be requesting more power than the switch can provide.  
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Crowdie, Champ

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Some cheaper switches cannot supply 802.3at power quick enough, have transformer limitations (you can only have one 802.3at device every four ports, for example) or have PoE power limits and these can cause the issue you describe.

Last year we became aware of the transformer issue with Cisco SG500 switches.  If you exceeded one PoE device per four ports the transformer couldn't handle it and the access points would either randomly reboot or radios would come up and down.   After working with a reluctant TAC the transformer layout in the Cisco SG500 was redesigned and the issue is now resolved.

PoE switches always have a PoE power limit and you need to ensure that the total PoE pull does not exceed this.  For example, some 24 port switches can only supply enough 802.3at power for eight devices.  If you plug in a ninth PoE device you start experiencing issues.  I believe you are running Cisco switches so you will be easily able to determine the PoE limit for these switches from the Cisco documentation.  
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MST

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Well, all is up the date: HM is 6.6 version, all 230 and 390 are updated as well. single floor is connected to stack of switches which one usually is WS-C3560X-24P-S so that switch is not cheap switch - usually costs around 4 - 5 K so and before we used Cisco Air Access Points with no single failure or problems with "power" from cisco switch side. Cisco is 802.3af—The IEEE standard for PoE, often referred to as IEEE-compliant.

I run the command to check the power:

Module   Available     Used     Remaining
          (Watts)     (Watts)    (Watts)
------   ---------   --------   ---------
1           720.0      257.6       462.4
2             n/a        n/a         n/a
Interface Admin  Oper       Power   Device              Class Max
                            (Watts)
--------- ------ ---------- ------- ------------------- ----- ----
Gi1/0/1   auto   on         15.4    Ieee PD             4     30.0
Gi1/0/2   auto   on         15.4    Ieee PD             4     30.0
Gi1/0/3   auto   off        0.0     n/a                 n/a   30.0
Gi1/0/4   auto   on         5.0     IP Phone 7911       2     30.0
Gi1/0/5   auto   on         15.4    Ieee PD             4     30.0
Gi1/0/6   auto   on         15.4    Ieee PD             4     30.0
Gi1/0/7   auto   on         15.4    Ieee PD             4     30.0
Gi1/0/8   auto   on         15.4    Ieee PD             4     30.0
Gi1/0/9   auto   on         15.4    Ieee PD             4     30.0
Gi1/0/10  auto   on         15.4    Ieee PD             4     30.0
Gi1/0/11  auto   on         5.0     IP Phone 7911       2     30.0
Gi1/0/12  auto   on         15.4    Ieee PD             4     30.0
Gi1/0/13  auto   on         5.0     IP Phone 7911       2     30.0
Gi1/0/14  auto   on         15.4    Ieee PD             4     30.0
Gi1/0/15  auto   on         5.0     IP Phone 7911       2     30.0
Gi1/0/16  auto   off        0.0     n/a                 n/a   30.0
Gi1/0/17  auto   on         5.0     IP Phone 7911       2     30.0
Gi1/0/18  auto   on         5.0     IP Phone 7911       2     30.0
Gi1/0/19  auto   on         15.4    Ieee PD             4     30.0
Gi1/0/20  auto   on         15.4    Ieee PD             4     30.0
Gi1/0/21  auto   on         15.4    Ieee PD             4     30.0
Gi1/0/22  auto   off        0.0     n/a                 n/a   30.0
Gi1/0/23  auto   on         12.0    IP Phone 7945       3     30.0
Gi1/0/24  auto   on         15.4    Ieee PD             4     30.0

so my AP with flapping wifi interfaces are gi1/0/5  & gi1/0/19 which shows consumption a less below 30W  


Interface Admin  Oper       Power   Device              Class Max
                            (Watts)
--------- ------ ---------- ------- ------------------- ----- ----
Gi1/0/5   auto   on         15.4    Ieee PD             4     30.0

Interface  AdminPowerMax   AdminConsumption
             (Watts)           (Watts)
---------- --------------- --------------------

Gi1/0/5               30.0                 30.0

Interface Admin  Oper       Power   Device              Class Max
                            (Watts)
--------- ------ ---------- ------- ------------------- ----- ----
Gi1/0/19  auto   on         15.4    Ieee PD             4     30.0

Interface  AdminPowerMax   AdminConsumption
             (Watts)           (Watts)
---------- --------------- --------------------

Gi1/0/19              30.0                 30.0


As you see power is at the level of 15.4 W


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Crowdie, Champ

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You certainly have more than enough PoE capacity so that isn't the issue.

If you manually set the PoE mode (Monitor -> [AP] -> Modify -> Advanced Settings -> PoE Mode) does the issue go away?