So the confusion is around the intended definition of the word "dynamic"? Sure, you can't rely on any feedback in a one way route situation. My point is that I

So the confusion is around the intended definition of the word "dynamic"? Sure, you can't rely on any feedback in a one way route situation. My point is that IP fragmentation, as a method, gets packets through a network that would otherwise be truncated or dropped by other methods. It can also do it reasonably efficiently and conveniently, moreso than always assuming a worst case MTU at the application protocol layer. I think what changes between methods is the use of fragmented packets to begin with? The whole premise is that IP fragmentation is bad because real world routers and firewalls don't support fragmentation properly. If fragmentation is deprecated, then wouldn't network stacks need to also start dropping oversized packets coming from user space applications?