CBS220-24P-4G PoE Issue

[tomfromeurope]

Hello Everyone,

i'm running into a very peculiar issue with a brand new CBS220 switch. When i connected the 2 PoE Accesspoints that we want to run to it, they powered up and worked with no issues. I then proceeded to configure the VLANs and ports to what is needed for our setup. Meaning i configured the Switchports to: Mode Trunk, VLAN allowed 1,2, Native VLAN 1.

This resulted in the switch no longer providing power to the Accesspoints.

I did not change any PoE settings while doing the configuration, i only changed the afforementioned VLAN settings. Strangely enough it also doesnt do anything to undo the configurations on those switchpowers. The switch just refuses to power the devices.

The Ports in Question are Gi23 & Gi 24. The Power line status looks as follows:

I did try various changes in PoE Configuration and the like, to no avail. I also tried a factory reset which resulted in PoE working again, until i did the Trunk configuration on the ports.

I installed the most current firmware for the device, which also didn't help.

Wishing you all a great day,and thanks in advance for any advice!

[marce1000]

 - Have a look  at this documentation ; https://www.cisco.com/c/en/us/td/docs/switches/lan/csbss/CBS220/CLI-Guide/b_220CLI/power_over_ethernet_poe_commands.html
   Start playing with some of the relevant commands and check if that can influence behavior

   + Use latest firmware available
   + Check logs on the cbs220 when a device is connected , look for errors related to POE

  M.

[tomfromeurope]

Thank you for your reply, 

i already attempted to solve the issue by fiddling with the power inline options. I tried changing supply from limit to class, as well as priority settings. I also found mention of energy efficient ethernet being a possible issue, which i also follwed up on.

I installed the newest firmware i could find from cisco. Afterwards i did a factory reset. this caused PoE to work again in default configuration, but when i changed the switchport to mode trunk the issue occured again ( after a restart of the switch).

What confuses me the most is that the state goes from searching to off but still recognises the devices class as class 4. I checked the logging and found no mention of any PoE issues. I looked in the errdisable if i can find anything there but theres nothing listed:

Since someone mentioned Smart Port, the CBS220 series does not support smart port, only the CBS250 series and higher. ( I checked the settings in my switch and the corresponding datasheets ).

Wishing you a great day,

Tom

[Flavio Miranda]

@tomfromeurope 

 Enable smartport feature

[tomfromeurope]

Thanks for your reply, i looked into this and found out that the CBS220 series does not have smart port support.

After being unable to find the options on the switch i checked the datasheet. Only the CBS250 series and higher have smart port listed as a feature.

Wishing you a great day,

Tom

[marce1000]

 - In the end I tend to believe that the CBS220 is probably too simple for the talk ; possibly getting confused to detect the AP and POE needs correctly when a trunk link is being, (not able to classify the AP) ; then using a higher switch model is better. I don't have any technical documents to confirm this however ,

 M.

[tomfromeurope · Accepted solution]

You might have a point there, about it getting confused. I did another factory reset and went with a step by step approach.

I checked the power status, configured 1 port only for Trunk, checked the power status again, reloaded the switch, checked again, and this time it seems to work for some reason.

The only difference i can discern is, that i did the trunk configurations for both ports at once ( via the interface range command ) and this time i did it one by one. So it might be a matter of the switch getting confused when using range commands.

I currently have both Ports configured correctly and the APs still recieve power. I will do some more testing before i trust the solution, but for now it seems to work.

Thank you again for your advice and time!

Tom