It's been a while since i had to deal with STP But can someone refresh my memory? Given the topology where i would have two nx9ks setup as a vpc domain feeding single switches (That will never cross connect to another set of switches), So it would be ( core_one <-vpcX-> Access switch < -vpcX-> core_two) There should never be another link from any other access switches to any other access switches that may be hanging off another vpc connection to the cores. Isn't there a way to keep STP isolated to each of those connections? EG the cores should NOT propagate any stp changes from one VPC to another? Or am i over thinking this somehow?