Ubiquiti and Cisco Spanning Tree

So a while ago I had posted here talking about getting into 10gig and using some USW-Agg switches to do so. After 3 or 4 months of them racked and running I decided that maybe they should actually be used lol (other priorities and life kept getting in the way).

I have them running 4 of them 2 in each rack and fully meshed. Everything is cool. Now my existing network was a pair of Cisco 3560x’s so I decided the next step was to break the link between them and insert the unif “core” in between… That is where things went sideways.

for clarity here is the before and after basic design

This is a multi step process. Eventually the Cisco server switch will go away once I migrate the servers into 10g. And the Pfsense boxes will be changed to feed directly from the AGG switches too. The other Cisco switch will stay as it has all my devices on it, or it might go to a unifi at some point too, undecided yet… I’m still learning and wrapping my head around how unifi does things with their switches. Having been a Cisco guy for years it is very different.

Any way the issue’s I’m having is basically spanning tree complaints and many kaboom moments where console cables have been my friend.

I gather from what I’ve managed to dig up it’s a conflict between Cisco’s per vlan STP and Ubiquiti’s RSTP . What seems to be the next logical step is to change the Cisco devices to MST but that seems to break everything.

Does any one have any guidelines around configuring Cisco and Ubiquiti to get them to talk nicely ? I realize they are like fire and water to each other so maybe I’m looking for a unicorn solution? so far other than “use MST” I don’t see much around any sort of guidelines

Do you have VLAN1 enabled on your trunks on the Ubiquiti switches? If not, try that.

Sorry for the delay in replying… Unfortunately work got in the way of playing.

I’ll take a look. I don’t use VLAN 1 for anything so it’s possible that I’m not passing it.

I also saw some details around needing to configure MTP on the cisco side to let them talk to each other with some code snippets referencing

spanning-tree mode mst
spanning-tree extend system-id
spanning-tree mst 0 priority 20480

on the cisco side, I haven’t had a chance to try it again… This weekend is looking promising.

Yep, the first thing I would try is adding VLAN1 to the trunks on the Ubiquiti side.

" Interoperability with PVST, PVST+, and Rapid Variants (Cisco)

When integrating with Cisco’s per-VLAN spanning tree implementations RSTP and STP are designated to the VLAN 1 instance of STP/RSTP on the Cisco switches."