WS-C3550-24-PWR 'Insufficient Power'

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Aug 2nd, 2010
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I have a Catalyst 3550 with PoE (WS-C3550-24-PWR) that has 1 x AP 1220 connected using PoE.  When I add 2 x AP 1242s, I get an insufficient power message.  How many devices using PoE can this switch support?  I'm running IOS v.12.1(19)EA1c - could this be an IOS update issue?  Thank you in advance.  -Jason

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Nagaraja Thanthry Mon, 08/02/2010 - 09:00
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Hello,


If you issue "show power inline", it will tell you the amount of power

delivered and the amount of power remaining. Typically the switch will have

360W of power and it can deliver 15.4 W per interface (max).


Hope this helps.


Regards,


NT

jasonpgutierrez Mon, 08/02/2010 - 09:58
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Hi,


Thanks for responding.  See below for the results of the 'show power inline'-


----snip--------------------

Interface  Admin    Oper     Power        Device           Class
                            (Watts)
---------- ----- ---------- ------- -------------------  ----------
Fa0/1      auto  on            6.2  cisco AIR-AP1220-IO  n/a
Fa0/2      auto  on           15.0  Ieee device
Fa0/3      auto  on           15.0  Ieee device
Fa0/4      auto  off           0.0  n/a                  n/a
Fa0/5      auto  off           0.0  n/a                  n/a
Fa0/6      auto  off           0.0  n/a                  n/a
Fa0/7      auto  off           0.0  n/a                  n/a
Fa0/8      auto  off           0.0  n/a                  n/a
Fa0/9      auto  off           0.0  n/a                  n/a
Fa0/10     auto  off           0.0  n/a                  n/a
Fa0/11     auto  off           0.0  n/a                  n/a
Fa0/12     auto  off           0.0  n/a                  n/a
Fa0/13     off   off           0.0  n/a                  n/a
Fa0/14     off   off           0.0  n/a                  n/a
Fa0/15     off   off           0.0  n/a                  n/a
Fa0/16     off   off           0.0  n/a                  n/a
Fa0/17     off   off           0.0  n/a                  n/a
Fa0/18     off   off           0.0  n/a                  n/a
Fa0/19     off   off           0.0  n/a                  n/a

Interface  Admin    Oper     Power        Device           Class
                            (Watts)
---------- ----- ---------- ------- -------------------  ----------
Fa0/20     off   off           0.0  n/a                  n/a
Fa0/21     off   off           0.0  n/a                  n/a
Fa0/22     off   off           0.0  n/a                  n/a
Fa0/23     off   off           0.0  n/a                  n/a
Fa0/24     off   off           0.0  n/a                  n/a
----snip--------------------


Below is the power draw on the AP from Cisco's website -


------snip-------------------

12.95W maximum

Note: 12.95W is the maximum power required at the powered device. If the access point is being used in a PoE configuration, the power drawn from the power sourcing equipment will be higher by some amount dependent on the length of the interconnecting cable. This additional power may be as high as 2.45W, bringing the total system power draw (access point and cabling) to 15.4W.

-----snip-------------------


Based on this info, all should be ok.  Any ideas on what else to check?


-Jason

Nagaraja Thanthry Mon, 08/02/2010 - 10:12
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Hello,


Can you please post the output of "show power inline", "show interface



Regards,


NT

rahurao Mon, 08/02/2010 - 11:44
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Hi Jason,



As per the output it only shows that the you have 3 devices connected and drawing power from the switch which is normal and the switch should be fine.


Can you send me the show power output and also can you let me know what device you are trying to conect and what is the minimum pwer requirement for the same.


HTH


Rahul

jasonpgutierrez Mon, 08/02/2010 - 12:08
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Rahul,


See below for requested info.  The APs are 1242s.


----snip--------------------

Interface  Admin    Oper     Power        Device           Class
                            (Watts)
---------- ----- ---------- ------- -------------------  ----------
Fa0/1      auto  on            6.2  cisco AIR-AP1220-IO  n/a
Fa0/2      auto  on           15.0  Ieee device
Fa0/3      auto  on           15.0  Ieee device
Fa0/4      auto  off           0.0  n/a                  n/a
Fa0/5      auto  off           0.0  n/a                  n/a
Fa0/6      auto  off           0.0  n/a                  n/a
Fa0/7      auto  off           0.0  n/a                  n/a
Fa0/8      auto  off           0.0  n/a                  n/a
Fa0/9      auto  off           0.0  n/a                  n/a
Fa0/10     auto  off           0.0  n/a                  n/a
Fa0/11     auto  off           0.0  n/a                  n/a
Fa0/12     auto  off           0.0  n/a                  n/a
Fa0/13     off   off           0.0  n/a                  n/a
Fa0/14     off   off           0.0  n/a                  n/a
Fa0/15     off   off           0.0  n/a                  n/a
Fa0/16     off   off           0.0  n/a                  n/a
Fa0/17     off   off           0.0  n/a                  n/a
Fa0/18     off   off           0.0  n/a                  n/a
Fa0/19     off   off           0.0  n/a                  n/a

Interface  Admin    Oper     Power        Device           Class
                            (Watts)
---------- ----- ---------- ------- -------------------  ----------
Fa0/20     off   off           0.0  n/a                  n/a
Fa0/21     off   off           0.0  n/a                  n/a
Fa0/22     off   off           0.0  n/a                  n/a
Fa0/23     off   off           0.0  n/a                  n/a
Fa0/24     off   off           0.0  n/a                  n/a
----snip--------------------


Below is the power draw on the AP from Cisco's website -


------snip-------------------

Power Draw for 1242

12.95W maximum

Note: 12.95W is the maximum power required at the powered device. If the access point is being used in a PoE configuration, the power drawn from the power sourcing equipment will be higher by some amount dependent on the length of the interconnecting cable. This additional power may be as high as 2.45W, bringing the total system power draw (access point and cabling) to 15.4W.

-----snip-------------------


Please let me know if you need additional info.


Thanks,

-Jason

Nagaraja Thanthry Mon, 08/02/2010 - 12:13
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Hello,


Which port you have connected the AP to? Also, in the output you have sent,

we are missing the total power details.


3550_1#sh power inline

Available:360(w) Used:0(w) Remaining:360(w)


Interface Admin Oper Power Device Class Max

(Watts)

rahurao Mon, 08/02/2010 - 12:16
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Hi Jason,



Thanks for the update!


Where as you have not provided the total power and power available in the show power inline output. Please share the same!!


How many AP's are we trying to connect to the switch at a time.


HTH


RAHUL

jasonpgutierrez Mon, 08/02/2010 - 12:23
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Rahul,


The command does not give me the total power.

There is currently one AP on the switch (on port 1).  I added 2 x 1242s on ports 2 & 3.


I am going to upgrade the IOS tomorrow and see if that helps.


Thanks,

-Jason

rahurao Mon, 08/02/2010 - 12:25
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Hi Jason,



Can you just give me the complete output of the show power inline ?



HTH

Rahul

jasonpgutierrez Mon, 08/02/2010 - 12:30
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See below -


-----snip-------

switch#sh power inline

Interface  Admin    Oper     Power        Device           Class
                            (Watts)
---------- ----- ---------- ------- -------------------  ----------
Fa0/1      auto  on            6.2  cisco AIR-AP1220-IO  n/a
Fa0/2      auto  on           15.0  Ieee device
Fa0/3      auto  on           15.0  Ieee device
Fa0/4      auto  off           0.0  n/a                  n/a
Fa0/5      auto  off           0.0  n/a                  n/a
Fa0/6      auto  off           0.0  n/a                  n/a
Fa0/7      auto  off           0.0  n/a                  n/a
Fa0/8      auto  off           0.0  n/a                  n/a
Fa0/9      auto  off           0.0  n/a                  n/a
Fa0/10     auto  off           0.0  n/a                  n/a
Fa0/11     auto  off           0.0  n/a                  n/a
Fa0/12     auto  off           0.0  n/a                  n/a
Fa0/13     off   off           0.0  n/a                  n/a
Fa0/14     off   off           0.0  n/a                  n/a
Fa0/15     off   off           0.0  n/a                  n/a
Fa0/16     off   off           0.0  n/a                  n/a
Fa0/17     off   off           0.0  n/a                  n/a
Fa0/18     off   off           0.0  n/a                  n/a
Fa0/19     off   off           0.0  n/a                  n/a

Interface  Admin    Oper     Power        Device           Class
                            (Watts)
---------- ----- ---------- ------- -------------------  ----------
Fa0/20     off   off           0.0  n/a                  n/a
Fa0/21     off   off           0.0  n/a                  n/a
Fa0/22     off   off           0.0  n/a                  n/a
Fa0/23     off   off           0.0  n/a                  n/a
Fa0/24     off   off           0.0  n/a                  n/a
switch#

-----snip-----------


-Jason

rahurao Mon, 08/02/2010 - 12:35
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Hi jason,



This is weired ! you are not getting the complete outputs with the commands. We are really not sure how much power it is consuming and how much is available.


Please proceed with a reload or upgrade and let me know the updated status on the same.


HTH

Rahul

Nagaraja Thanthry Mon, 08/02/2010 - 12:54
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  • Cisco Employee,

Hello Jason,


The issue seems to be hardware related. In order for us to narrow down the

problem, please follow the below troubleshooting steps:


Step 1: Disconnect the AP in question


Step 2: Configure logging on the switch


configure terminal

logging on

logging buffered debugging


Step 3: Enable inline power debugs


switch# debug ilpower events


Step 4: Now connect the AP in question and wait for a minute


Step 5: Now collect the output of "show log"


The output will show us the negotiation between the AP and the switch with

regard to the power requirements. Typically, the switch will reject power

allocation if the AP is asking for power beyond what switch can provide or

if it does not recognize the AP at all. Once we figure out what is the root

cause, it is easy to find a fix.


Hope this helps.


Regards,


NT

Leo Laohoo Mon, 08/02/2010 - 15:12
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I am going to upgrade the IOS tomorrow and see if that helps.

Upgrade to what?  There are two directions.  You can upgrade to either 12.1(22)EA13 or 12.2 series.  If you have the service contract, upgrade to the 12.2 instead (IP Base).
jasonpgutierrez Tue, 08/03/2010 - 08:01
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I upgraded the switch to the latest IOS (v12.2(44)SE6) and that resolved the problem.  The  APs can connect and I can see the power stats.  See below -

----snip-----

Available:360(w)  Used:37(w)  Remaining:323(w)

Interface Admin  Oper       Power   Device              Class Max
                            (Watts)
--------- ------ ---------- ------- ------------------- ----- ----
Fa0/1     auto   on         6.2     AIR-AP1220-IOS-UPGR n/a   15.4
Fa0/2     auto   on         15.4    Cisco PD            n/a   15.4
Fa0/3     auto   on         15.4    Cisco PD            n/a   15.4

---snip------


Thanks to all for your input.


-Jason

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