Wednesday, February 13, 2019

Disjoint Spanning tree instances, all ports forwarding.

Reddit,

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I'm looking for some advice as my google-fu seems to be failing me in finding the answers I'm looking for.

I have diagramed the topology/network segment I'm referring to: https://imgur.com/a/CWxBio5

  • My end goal is to decomission the Cisco stack as we no longer have support/need for it within our environment.

This was all configured prior to me joining the company and have come in blind as there was no documentation on anything. I am i no means a networking engineer and I am seeking some guidance.

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When checking the STP configuration on the Cisco stack and HP Switch1/2 both port channels are in a forwarding state on both sides. To me this would mean there is a networking loop. The HP switches are not stacked and not MLAG capable. I am confused as to why this would be the case. I can only assume it's due to the disjointed STP instances and BPDU's not making it through correctly.

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My aim is to move the port channels from the Cisco stack to the Huawei stack. I am unsure on how STP would react when carrying this out. If both portchannels remained in a forwarding state could this 'loop' be more catastrophic?

On the HP side the portchannel has "no spanning-tree auto-edge-port" defined in it's config. There's no specific spanning-tree config on the Cisco interfaces/portchannels. there's no BPDU filtering that I can see it just seem's the Cisco stack is not passing them and not allowing for loop detection to take place.

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Can anyone help shed some light or point me in the right direction on how best to proceed?

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Thanks,



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