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CISCO SWITCHES FOR SMALL and MEDIUM BUSINESS

Introducing the next generation of Cisco Small and Medium Business Switches. Cisco is refreshing its SMB Switch portfolio. Click here  to learn more.


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Beginner

STP blocking

Hi there, 

Thanks for reading.

 

I have SG220 switches which are cycling through blocking, learning & forwarding.  We've gone through the building and removed mini switches but the problem continues.  Here's what it's logging (and it repeats throughout the day):

2Jun 09 2020 07:06:40infoFastEthernet19 STP port state is set to Forwarding
3Jun 09 2020 07:06:25infoFastEthernet19 STP port state is set to Learning
4Jun 09 2020 07:06:05infoFastEthernet19 STP port state is set to Blocking
5Jun 09 2020 07:06:05noticeFastEthernet19 link up
6Jun 09 2020 07:06:03infoFastEthernet19 STP port state is set to Disabled
7Jun 09 2020 07:06:03noticeFastEthernet19 link down

 

Maybe just enabling BPDU guard?  It's just odd because we removed desktop switches.

Anyway, thanks again for reading!

Bob

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VIP Mentor

Re: STP blocking

First, you need to investigate is there any L2 Loops in the network, start from Port 19 which as mentioned in the network.

 

Once it is confirmed there are no Loops. make a small network diagram, is there ay connection to going to other switches.

 

then based on the network take a call to enable the feature required :

 

here is document :

 

https://www.cisco.com/c/en/us/support/docs/smb/switches/cisco-small-business-200-series-smart-switches/smb81-setup-spanning-tree-protocol-stp-on-a-interface-on-the-200-3.html

BB
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