Unable to configure 802.3at PoE on a 3750X switch.

[Mogwai]

Hey guys, hoping another set of eyes may be able to help. I've setup a new Cisco 3750X switch & have connected a 2802i AP to port fa1/0/10.  This AP isn't booting properly due to not getting enough PoE.  Currently, it's only getting 15.4W (802.3af) rather than the 25W it needs. 

MSN-IDF9-3750X#sho power inline

Module   Available     Used     Remaining
          (Watts)     (Watts)    (Watts) 
------   ---------   --------   ---------
1           370.0       77.0       293.0
Interface Admin  Oper       Power   Device              Class Max
                            (Watts)                            
--------- ------ ---------- ------- ------------------- ----- ----
Fa1/0/1   auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/2   auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/3   auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/4   auto   on         15.4    Ieee PD             0     15.4 
Fa1/0/5   auto   on         15.4    Ieee PD             0     15.4 
Fa1/0/6   auto   on         15.4    Ieee PD             0     15.4 
Fa1/0/7   auto   on         15.4    Ieee PD             0     15.4 
Fa1/0/8   auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/9   auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/10  auto   on         15.4    AIR-AP2802I-B-K9    4     15.4 
Fa1/0/11  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/12  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/13  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/14  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/15  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/16  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/17  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/18  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/19  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/20  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/21  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/22  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/23  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/24  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/25  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/26  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/27  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/28  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/29  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/30  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/31  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/32  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/33  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/34  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/35  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/36  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/37  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/38  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/39  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/40  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/41  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/42  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/43  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/44  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/45  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/46  auto   off        0.0     n/a                 n/a   15.4 
Fa1/0/47  auto   off        0.0     n/a                 n/a   15.4 
Interface Admin  Oper       Power   Device              Class Max
                            (Watts)                            
--------- ------ ---------- ------- ------------------- ----- ----
Fa1/0/48  auto   off        0.0     n/a                 n/a   15.4 

When I attempt to configure this the switch appears to be limited to only putting out 15.4W. 

MSN-IDF9-3750X(config-if)#power inline auto max ?    
  <4000-15400>  milli-watts

According to Cisco's specs for this switch it is capable of 802.3at. Any ideas on what the issue is?

[Leo Laohoo]

Look at the right-most column of the command "sh power inline".  It says "MAX".  

And the maximum PoE this switch model (FastEthernet ports) will do is 15.4wac.  The model with GigabitEthernet access ports can support up to 30.0wac.

[Mogwai]

Ah ok, thanks for the clarification. Do you happen to know if that updating the firmware would allow 802.3at for this switch or do I simply need a newer model?

[Leo Laohoo · Accepted solution]

The 15.0wac PoE limit is set by the PoE module built into the motherboard.  No amount of software upgrade will change it. 

It is easier and faster to look in the used market to look for a model which can support 30.0wac.

[JPavonM]

As @Leo Laohoo  mentioned these are as per Cisco DS the only PoE+ capable models:

[Mogwai]

Thanks for that!  This is: Model number : WS-C3750V2-48PS-S

Figures it seems that every other site lists this model as having 40x PoE+ ports rather that just PoE. 

Oh well, looks like off to the closet to swap some non-PoE devices over to the new switch & leave the 3850 to handle the PoE. Thanks for the help!

[Rich R]

3750V2 (definitely not 3750X LOL) is very old - went end of support more than 2 years ago:
https://www.cisco.com/c/en/us/products/collateral/switches/catalyst-3750-series-switches/eos-eol-notice-c51-730227.html
After the last date of support Cisco start removing all software and documentation from their web site so that's why you'll struggle to find that info on cisco.com.  You can still find it on 3rd party sites like:
https://www.andovercg.com/datasheets/cisco-3750V2-series-switch.pdf
3750V2-48PS 48 Ethernet 10/100 ports with PoE and 4 SFP Gigabit Ethernet ports; 1RU

[Rich R]

If you do "show ver" or "show inventory" what is the actual exact model number or product ID (PID) shown for your switch?

Simply stating 3750X is insufficient and it probably is not a 3750X as the others have highlighted.  The giveaway is that your switch has FastEthernet ports whereas the 3750X models have at least GigabitEthernet ports.  You're likely using an older model switch with only FE ports supporting POE (af) not POE+ (at).
https://www.cisco.com/c/en/us/products/collateral/switches/catalyst-3560-x-series-switches/data_sheet_c78-584733.html#SwitchModelsandConfigurations

Once you have the correct switch you shouldn't need to configure the power on the port - just make sure CDP is enabled on the port so that the AP can negotiate power required.  (You can also use LLDP instead of CDP if preferred but should never enable both at the same time).  Cisco default is CDP.