Hi Tom, I am thinking about source-fragmentation only, then send all fragments with DF=1 so they won't be further fragmented in the network.
One use case would be for IP-in-IPv4 tunneling when there is no GUE header. I haven't thought much about other use cases, but it should apply to any IP/X encapsulations (X could be TCP, for example). Thanks - Fred > -----Original Message----- > From: Tom Herbert [mailto:[email protected]] > Sent: Tuesday, May 23, 2017 10:38 AM > To: Templin, Fred L <[email protected]> > Cc: [email protected]; Joe Touch <[email protected]> > Subject: Re: [Int-area] IPv6 fragmentation for IPv4 > > On Tue, May 23, 2017 at 9:17 AM, Templin, Fred L > <[email protected]> wrote: > > Joe, I wanted to run an idea by you. We all know that IPv4 fragmentation has > > problems because of the 16-bit ID field. So, why not insert an IPv6 Fragment > > Header between the IPv4 header and the upper layer protocol data, then > > use IPv6-style fragmentation instead of IPv4 fragmentation? > > > Hi Fred, > > What is the use case for this? Unlike IPv6, IPv4 fragmentation can be > done a routers so this technique wouldn't work in that case. If the > fragmentation is occurring at tunnel ingress its probably just as easy > to fragment as part of the encapsulation like we do in GUE. > > Tom > > > So, the IPv4 Protocol field would be set to '44', the IPv4 header would be > > followed by an IPv6 Fragment Header, and the "Next Header" field in the > > IPv6 Fragment Header would be set to the Protocol Number for the upper > > layer protocol. Then, upon fragmentation, each fragment would have an > > IPv4 header followed by an IPv6 Fragment Header. > > > > This format is shown in Figure 6 in Appendix A of the AERO draft: > > > > https://datatracker.ietf.org/doc/draft-templin-aerolink/ > > > > Does this look like something that should be broken out and put into a > > little standalone document? > > > > Thanks - Fred > > > > _______________________________________________ > > Int-area mailing list > > [email protected] > > https://www.ietf.org/mailman/listinfo/int-area _______________________________________________ Int-area mailing list [email protected] https://www.ietf.org/mailman/listinfo/int-area
