POE bug with catalyst 4500 switches and series 1130 aps?

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Jul 23rd, 2009
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I have 2 cisco AIR-AP1131AG-A-K9 access points plugged into a WS-C4506. The Inline power readings seem a comically high for these devices:


10-2A-sw1#sh power inline gi2/40

Available:800(w) Used:666(w) Remaining:134(w)


Interface Admin Oper Power(Watts) Device Class

From PS To Device

--------- ------ ---------- ---------- ---------- ------------------- -----


Gi2/40 auto on 429495 42940. AIR-AP1131AG-A-K9 3


Interface AdminPowerMax AdminConsumption

(Watts) (Watts)

---------- --------------- --------------------


Gi2/40 15.4 15.4

10-2A-sw1#sh power inline gi2/41

Available:800(w) Used:666(w) Remaining:134(w)


Interface Admin Oper Power(Watts) Device Class

From PS To Device

--------- ------ ---------- ---------- ---------- ------------------- -----


Gi2/41 auto on 429495 42940. Ieee PD 3


Interface AdminPowerMax AdminConsumption

(Watts) (Watts)

---------- --------------- --------------------


Gi2/41 15.4 15.4


This also appears to be service affecting, we cannot add any new poe devices to this switch without first re-setting these APs. But soon after the AP restarts (within ~1 min), the inline power numbers rise to what's posted above. Users are still able to connect to our wireless network through these APs. Is this a bug with our IOS version or something else?


More, relevant information:


10-2A-sw1#sh ver

Cisco IOS Software, Catalyst 4000 L3 Switch Software (cat4000-I9S-M), Version 12.2(25)EWA10, RELEASE SOFTWARE (fc1)

Technical Support: http://www.cisco.com/techsupport

Copyright (c) 1986-2007 by Cisco Systems, Inc.

Compiled Wed 11-Jul-07 00:08 by dchih

Image text-base: 0x10000000, data-base: 0x114BC038


ROM: 12.2(20r)EW1

Dagobah Revision 226, Swamp Revision 34


10-2A-sw1 uptime is 24 weeks, 5 days, 21 hours, 56 minutes

System returned to ROM by power-on

System image file is "bootflash:"


cisco WS-C4506 (MPC8245) processor (revision 10) with 262144K bytes of memory.

Processor board ID FOX07041HR4

MPC8245 CPU at 266Mhz, Supervisor II+

Last reset from PowerUp

2 Virtual Ethernet interfaces

98 Gigabit Ethernet interfaces

511K bytes of non-volatile configuration memory.


Configuration register is 0x2101


10-2A-sw1#sh mod

Chassis Type : WS-C4506


Power consumed by backplane : 0 Watts


Mod Ports Card Type Model Serial No.

---+-----+--------------------------------------+------------------+-----------

1 2 Supervisor II+ 1000BaseX (GBIC) WS-X4013+ JAE1130S21C

2 48 10/100/1000BaseT (RJ45)V, Cisco/IEEE WS-X4548-GB-RJ45V JAE1132TM62

3 48 10/100/1000BaseT (RJ45)V, Cisco/IEEE WS-X4548-GB-RJ45V JAE1133U3X5


M MAC addresses Hw Fw Sw Status

--+--------------------------------+---+------------+----------------+---------

1 000c.3098.dbc0 to 000c.3098.dbc1 4.3 12.2(20r)EW1 12.2(25)EWA10 Ok

2 001d.4505.2510 to 001d.4505.253f 3.3 Ok

3 001c.58a6.55c0 to 001c.58a6.55ef 3.3 Ok


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glen.grant Thu, 07/23/2009 - 16:31
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It's telling you its drawing 15.4 watts , thats normal . The other number is the total power available for powering devices . you should still have 134 watts available to draw. I have never seen a POE issue with any AP drawing too much power , may be something else going on . Are the power supplies too small for what you are trying to do ?

jcmillions Thu, 07/23/2009 - 19:40
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The chassis has 2x 1300watts power supplies, as recommended by the power calc. I realize the system says there is available power, but when connecting additional VoIP phones the switch logs the message:


24w5d: %ILPOWER-5-ILPOWER_POWER_DENY: Interface Gi2/17: inline power denied


Power is not granted to the additional VoIP phone until I cycle the above APs. The only hint as to a possible cause is the erroneous wattage numbers recorded:


10-2A-sw1#sh power inline module 2

Available:800(w) Used:680(w) Remaining:120(w)


Interface Admin Oper Power(Watts) Device Class

From PS To Device

--------- ------ ---------- ---------- ---------- ------------------- -----


Gi2/1 auto on 7.9 7.0 Ieee PD 2

Gi2/2 auto on 17.3 15.4 Ieee PD 3

Gi2/3 auto off 0.0 0.0 n/a n/a

Gi2/4 auto on 17.3 15.4 Ieee PD 3

Gi2/5 auto on 17.3 15.4 Ieee PD 3

...

...

Gi2/38 auto on 17.3 15.4 Ieee PD 3

Gi2/39 auto off 0.0 0.0 n/a n/a

Gi2/40 auto on 429495 42940. AIR-AP1131AG-A-K9 3

Gi2/41 auto on 429495 42940. Ieee PD 3

Gi2/42 auto off 0.0 0.0 n/a n/a

Gi2/43 auto off 0.0 0.0 n/a n/a

Gi2/44 auto off 0.0 0.0 n/a n/a

Gi2/45 auto off 0.0 0.0 n/a n/a

Gi2/46 auto off 0.0 0.0 n/a n/a

Gi2/47 auto on 17.3 15.4 Ieee PD 3

Gi2/48 auto off 0.0 0.0 n/a n/a

--------- ------ ---------- ---------- ---------- ------------------- -----


Totals: 21 on 280.2 86148.


iyde Fri, 07/24/2009 - 04:49
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It looks like buggy code or something, as it says the power for the AP is 429495..

The figure 429495 is equal to 2*16, I believe. In other words, it looks like some counter has set itself to all binary one's instead of measuring the right value.

You might want to try a newer IOS for the switch to ensure fwer bugs.

HTH.

jbrenesj Mon, 07/27/2009 - 12:19
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The bug is


CSCsk11184

IEEE POE devices incorrectly allocated too much power


Duplicate-of CSCsj47170

12.2(25)EWA10 : show power inline command not showing the proper power


Fixed in 12.2(25)EWA12


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