Wednesday, February 13, 2019

Disjoint Spanning tree instances, all ports forwarding.

Reddit,

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.

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.

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.

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

Thanks,



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