9120-AXI in low power mode

[daniel.tanch]

Hi, 

Currently I am facing this issue. The AP(9120-AXI) is in low power mode when it is connected to a media converter(MC). From my understanding, 9120-AXI required 802.3at(25.5w) to have the full functionality which indeed the MC support 802.3at & 802.3af. But it always seem like the AP keep stating there is insufficient power. A MC is use due to the distance from the switch to AP is more than 100m. How to ensure that the AP will be getting 802.3at?

Physical connection:

Non-PoE switch ----- MC ----- AP

[Rafael E]

AP needs CDP or LLDP to power up correctly if not connected to a supported power injector. 

Not sure what are the capabilities for that MC.

[daniel.tanch]

Media converter is used when the distance from the switch toward the AP is more then 100m. Thus fiber is connected from the switch to the MC and from the MC it copper toward the AP which will also power up the AP. It 

[SW]---(fiber)---[MC]---(Copper)---[AP]  

[Scott Fella]

Take a look at the output from the ap console while booting up the ap. Maybe the ap isn’t able to negotiate prefect power with the MC.

[Scott Fella]

You try looking at adding a power injector to the other end to see if the ap comes up? Connect this to the copper port of the MC.

https://www.cisco.com/c/en/us/td/docs/wireless/access_point/power/guide/air_pwrinj6.html

[Rich R]

I've used 9120-AXI with PWRINJ6 and it works fine so I think you're back to the question @Rafael E asked which you did not answer: does your MC support CDP or LLDP? If not then it is not compatible with the AP.

[daniel.tanch]

The MC is a unmanaged device, the purpose of it was to convert fiber to copper due to copper limitation which is 100m. The MC don't support CDP or LLDP, these protocol are only supported if it a networking devices. Does PWRINJ6 supported CDP or LLDP?

[Rich R]

I would assume it does. If in doubt consult the documentation - then if you have a problem you can take it up with Cisco. If you use unsupported devices then you're on your own:
https://www.cisco.com/c/en/us/products/collateral/wireless/catalyst-9120ax-series-access-points/datasheet-c78-742115.html#Productspecifications
Input power requirements

● 802.3at Power over Ethernet Plus (PoE+), 802.3bt Cisco Universal PoE (Cisco UPOE+, Cisco UPOE ®)
● Cisco power injector, AIR-PWRINJ6=
● 802.3af PoE
● Cisco power injector, AIR-PWRINJ5= (Note: This injector supports only 802.3af)

[daniel.tanch]

Hi Scott,
I had tried using a power injector (not AIR-PWRINJ6) but it able to supply 50-60watt of power. But the problem still exist, the AP only get 15.4watt.

[Scott Fella]

Well if you tired using the Cisco power supply and it still didn’t work, then I don’t know. I have used various Cisco power injectors with no issue supplying power. You will see that in the console output, so I’m assuming your output show the ap not negotiating power?

[Rich R]

Have you checked that you have CDP enabled on the AP (advanced tab) and the LAN interface (must be enabled on both)?
If CDP (or LLDP where required) is turned off the AP will never use more than 15.4W.