On 3/6/2019 8:22 AM, Tom Herbert wrote: > On Tue, Mar 5, 2019 at 10:08 PM Joe Touch <[email protected]> wrote: >> Isn't the biggest problem with IP fragmentation the inability to NAT >> because the transport headers are in the first fragment only (which may >> go via another path)? >> > Joe, > > The size of the IP identifier is mentioned as one of the problems with > IPv4 fragmentation in draft-ietf-intarea-frag-fragile.
That could have been handled by new rules to drop incompletely reassembled datagrams based on measured expected reordering, rather than max lifetime. > The fact that > intermediate nodes might fragment in IPv4 and not in IPv6 is another > discrepancy between the protocols. Well, strictly the difference is only whether intermediate nodes violate IPv4 or IPv6. IPv4 with DF isn't supposed to be on-path fragmented any more than IPv6 is; in both cases, nodes that violate the protocols can - and will - do whatever they want. But there's no point in making "laws for the lawless", as I've repeatedly noted throughout the IETF. > The transport layer not in all > fragments is a problem for NAT, that might addressed by encapsulating > the fragmention in UDP. That is a problem for NAT and transport-based ECMP. And yes, we can build an Internet on the Internet - again, as I've noted repeatedly throughout the IETF. Or we can use UDP fragmentation - which ought to solve all these issues in one shot. So what's the gain here? Joe _______________________________________________ Int-area mailing list [email protected] https://www.ietf.org/mailman/listinfo/int-area
