Disable spanning tree on 2724?

Question

We are a Cisco shop, but we commonly use 2724 switches when we need a low cost unmanaged gb switch. It is useful when we have a large group of servers all on the same VLAN. We disable BPDU guard on the Cisco port since there is very little chance of creating a loop. The 2724 will only connect to one switch using only one link.

In any case, we now have a Cisco access layer with fabric extenders. These fabric extenders are hard-coded with BPDU guard so I can't disable it. As soon as I connect a 2724 to it, the Cisco switch puts the port into err-disabled state because it received a BPDU on that port. I'd like to disable spanning tree on the 2724 but I don't see an option when browsing through the web management. Am I missing something here?

rsjordan00 · Answer

From the user guide, it seemed spanning tree wasn't a feature. But, then why would it send BPDUs? Could it be that the switch does run spanning tree, but it does not have a "feature" to control settings? I did confirm I was running the latest firmware: 1.0.1.07.

I'm using a Nexus 5548 with a Nexus 2248 extender. Here is the error thrown from the Cisco switch:

Interface Ethernet100/1/1 is down (Error disabled. Reason:BPDUGuard)

As I mentioned before, it is not possible to disable BPDU Guard on a FEX port. I did just come across an option for BPDU Filter. I'm going to enable this on the port and see if it helps.

Thanks

rsjordan00 · Answer

I applied 'spanning-tree bpdufilter enable' to the Fex interface and it did the trick. Of course, if you're not careful, you could end up with a loop. Thanks

Networking General

Disable spanning tree on 2724?

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