> The problem is that you end up having two streams, one fragmented and > one non-fragmented, but actually they belong to the same stream. It is > known to break stuff, see: > > <https://patchwork.ozlabs.org/patch/59235/> > > I would agree with you, but we can't break existing setups, > unfortunately. > I'm not sure what "existing setups" means here. If this is referring to the Internet then out of order packets and fragments abound-- any assumption of in order delivery for IP packets is useless there.
Btw, TCP has exactly the same problem in this regard that UDP has with regard to fragmentation. The reason that TCP isn't considered an issue is the assumption that TCP will do PMTU discovery and set DF (I would bet that devices don't actually check for DF and vendors don't test when it's not set!). Tom
