STP Change on Access Port

SOLVED
jwwork
Getting noticed

STP Change on Access Port

I am working with support on an issue where randomly we have a network interruption that looks like it's caused by some aggregate ports on our MS425 going down and back up and causing spanning tree topology change.  The MS425 is the core switch stack.  Anyway, looking in the event log I see this a lot on all of our access ports on our MS350's.  This is just a normal port connected to a desktop computer.  This happens every time a computer is turned on.  Is it normal for that to be logged as a STP change?  I assume it's normal just wanted to make sure.

 

Here is an example:

access_stp.png

 

 

 

 

Here is the config from that port.

 

portconfig.png

1 ACCEPTED SOLUTION
jdsilva
Kind of a big deal

Oh, sorry, I misunderstood the question. Yes, they are normal. 

 

View solution in original post

7 REPLIES 7
kYutobi
Kind of a big deal
jdsilva
Kind of a big deal

Hey @jwwork ,

 

In RSTP, a Topology Change (TC) is generated when a non-edge port moves into the forwarding state. It's for this reason it's important to put BPDU Guard on your host facing ports as that marks them as "edge" so a flap won't generate a TC. 

 

 

jwwork
Getting noticed

I know, in the screenshot you can see that I have BPDU guard enabled on this port like I do all my access ports.  Just curious if the STP messages in the log are normal.

jdsilva
Kind of a big deal

Oh, sorry, I misunderstood the question. Yes, they are normal. 

 

jwwork
Getting noticed

Thank you!  Is there a different message that is logged when there is actually a topology change?

jdsilva
Kind of a big deal

Not that I've seen, no.

Thygesen
Building a reputation

Hi @jwwork !


I see similar behaviour on a couple of switches running MS 11.30..

Thygesen_0-1581590526553.png

 

Thygesen_0-1581590344719.png

Thygesen_1-1581590359253.png

 

 

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