Maxim and myself continued our STP discussion and eventually agreed that while STP might not be the best protocol out there (remember: it had to run on Z80 CPU), it’s the only standardized thing that prevents nasty forwarding loops, prompting Maxim to ask another seemingly simple question:
What's so wrong with STP, that there are STP haters out there turning it off wherever they see it?
Welcome to the wonderful world of Expert Beginners.
Imagine you’re facing a problem where VMs get cut off from the network after a server-to-switch link is reestablished or where it takes workstations “forever” to connect to the network. You might even figure out that the switch port stays stuck in something called listening for half a minute. Googling around you find the listening state has something to do with something called STP, and you have no clue why you’d need something called STP in your network. Next step: googling for configuration commands that will turn off STP.
Please note that the VM-related behavior is effectively a broken VMware vSwitch design decision. SMB engineers shouldn’t have been forced to deal with stupidities like this one.
Alternatively, you might have configured portfast and BPDU guard in the past (based on yet another Google search result), and get hit by a Windows VM entering bridging mode. You want to stop all this nonsense for good, and the only way to do that is to turn off STP.
Do I have to mention that lack of BPDU handling is yet another vSwitch problem, and that VMware still doesn’t get it?
It would be exceedingly easy to blame the expert beginners making these mistakes, but in reality it’s sad when you figure out many pointy-haired bosses think their engineers need no training, and even worse to realize that many IT practitioners think “fake it till you make it” is not a bad idea.