CBS250-8P major bridge bug (STP/PVID)

[Jessen Ranellucci]

Hello,

I'm utilizing this channel to report a bug because it seems that Cisco is not addressing glitches without a support contract, even though we have purchased numerous switch products from them and should be considered valued clients. With my CCNA v2 certification and years of experience with SG series, I am familiar with how a Cisco switch should operate.

Please be cautious regarding CBS250-8PORTS switches, as they evidently have a firmware issue present in all versions. The problem is as follows: the switch's Spanning Tree Protocol (STP) keeps blocking ports and reverting them to the default vlan1, falsely indicating a PVID mismatch when there is none. Consequently, if you attempt to apply best practice configurations as recommended by Cisco, the switch becomes non-functional as it randomly but consistently reverts to vlan1. The setup is straightforward; the 8 ports are connected to the main 48-port switch using the same custom PVID on the port using the very same port mode. Despite this, STP incorrectly identifies it as a mismatch, causing the switch STP protection to kick in.

If a cisco developper ever read this you can quickly validate what I am advancing here as you can test it easly, just setup a master switch and bridge it with the 8p using a custom pvid then just reboot the 8p you will see STP on both switch sending alerts and you will defenitly loose com with the 8p.

I did lookup on the bug search tool and there is only POE bug reported for this model as of right now.

[liviu.gheorghe · Accepted solution]

Hello @Jessen Ranellucci ,

as per Cisco documentation, you don't need a support contract to access the technical support for your CBS250:

Q. What is the warranty?

A. Cisco Business switches come with a Limited Lifetime (CBS350, CBS250 and CBS110 series) or 3-year warranty (CBS220 series). If there are any hardware defects, Cisco will replace the product upon receipt of the defective device. In addition, the warranty includes free access to technical support during local business hours, 8 hours per day, 5 days per week, for a period of 1 year from the original date of purchase. Software bug fixes are available for the life of the products.

Cisco Business 350 Series Managed Switches come with an Enhanced Limited Lifetime Warranty (ELLW), which provides next-business-day advance replacement where available in addition to the standard coverage in LLW.

Product warranty terms and other information applicable to Cisco Business products are available at https://www.cisco.com/go/warranty.

I think you can go ahead and open a TAC case if your switch is not older than 1 year.

Hope this helps.

[Jessen Ranellucci]

Hello @liviu.gheorghe,

I appreciate your prompt response and the additional information you shared regarding licensing, which has helped me understand how to initiate a TAC ticket.

My inclination towards considering this a firmware issue, rather than a hardware one, stems from the fact that I encountered the same problem on two newly deployed "CBS250-8P" switches.

I'm proceeding now to open a TAC case.

Best regards,

Jessen