PSA: Avoid CBS350 Switches - Critical POE Defect

[d0nni3q84]

Hello Community,

I'm writing to let you know that there is a critical POE defect in the CBS350 switches and you should avoid them if you require stable POE operations. This apparent software defect causes POE ports to randomly fault after 8 to 12 hours and the powered device will go offline. Cisco does not have a resolution, workaround, or timeline to address this situation.

Please help Cisco prioritize this issue by opening a TAC case if you are experiencing this issue. Additionally, please escalate this for additional visibility through your sales channels.

All the best!

[d0nni3q84]

The issue is resolved in the 3.2.xx releases and also requires an MCU update. I'm running 3.2.0.89 and have been stable for several months. Follow the instructions here: https://www.cisco.com/c/en/us/support/docs/smb/switches/Cisco-Business-Switching/kmgmt3492-recommended-practices-firmware-update-cbs.html.

[ehuneycutt]

Thanks

[Throwback3952]

Issue still persist on 3.4.0.17.

Cbs350 detect short condition on completely valid port with 802.3af . On all another switches which are not CIsco devices works without any problem. So recommendation to avoid CBS350 for PoE operations still valid. Even crap dumb tp-link working better.

[d0nni3q84]

Still solid and resolved with version 3.2.1.1

[KJK99]

@Throwback3952 

"Issue still persist on 3.4.0.17."

Really? No POE issues with my CBS350 switches.

[Throwback3952]

Yes we have quite a big batch of cbs350 switches and all of them not stable even with latest firmware. If we connect more than 2 devices which eat 5 watt  after it switches become not stable and does not provide power to another ports . On ports with devices which are not working its detect "Port is off. Short condition" but it is not truth because in same time same devices connected together to crap cheap poe tp-link working without any problem.

[cyberconsultants]

you've failed to mention what PDs you're connecting. it wouldn't happen to be Ubiquiti gear, would it? something else? if the latter, can you share where its PoE-compliance is stated?

[Throwback3952]

PD is Mikrotik Cube pro AC https://mikrotik.com/product/cube_60pro_ac

Working good with any another switches except Cisco

[cyberconsultants]

got it. your situation makes much more sense now.

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Working good with any another switches except Cisco

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we actually use that as a litmus to determine what hardware to avoid. enterprise grade gear and non-enterprise grade gear are usually never a good mix. but you've offered that you have some "crap cheap poe tp-link" gear lying around, so at least there's that.

[shikakabat]

Adding our experience here: We have several CBS350's. Two of them have exhibited this issue over the past year. The latest occurrence was on a switch running 3.4.0.17; it randomly dropped PoE to Meraki AP's. No errors on the switch; port status said "searching". A reload resolved it.

This is obviously still an issue.