Ivan Pepelnjak of ipSpace.net comments:

Maxim Gelin sent me an interesting question:

Can you please explain to me, why is STP supposed to be evil? What’s wrong with STP?

STP’s fundamental problem is that it’s a fail-close, not a fail-open protocol.

This is a wonderful analysis from Ivan about the problems with spanning tree and why it behaves the way it does. Worth a read for sure.

Read more at: Is STP Really Evil?