Hi Ole, > -----Original Message----- > From: Ole Troan [mailto:[email protected]] > Sent: Tuesday, September 03, 2019 2:22 PM > To: Templin (US), Fred L <[email protected]> > Cc: Bob Hinden <[email protected]>; Tom Herbert <[email protected]>; > Joel Halpern <[email protected]>; draft- > [email protected]; [email protected]; IESG <[email protected]>; > [email protected] > Subject: Re: [Int-area] Alissa Cooper's No Objection on > draft-ietf-intarea-frag-fragile-16: (with COMMENT) > > Fred, > > >> Why is that more useful than what is in 3.5? If it’s not making a > >> recommendation, why call this out in the introduction. There are lot > of > >> other things it doesn’t make recommendations about that aren’t in the > >> Introduction either. > > > > Because it sets a more appropriate tone and lets the reader know from the > > onset that > > fragmentation and encapsulation go hand in hand. And tunnel fragmentation > > avoids the > > issues raised by others in this thread. > > While inner fragmentation ensures the fragment will reach the tunnel tail > end, a tunnel endpoint will typically not reassemble that > fragment, so will generate fragments after the tunnel hop. > Inner fragmentation is only available on IPv4.
Not true. For IPv6 packets, simply insert a GUE header or an RFC2473 header and fragment on that. The fragments will be reassembled by the tunnel tail end, then passed to the next hop as a whole IPv6 packet. The fragmentation footprint is therefore the same as the tunnel footprint. > Outer fragmentation will look like any other fragmented packet, I am not talking about outer fragmentation. > albeit that the tunnel tail now has to reassemble. At speeds typically > much higher than a typical end host. Using iperf3, I can show fragmentation and reassembly at near line-rate on 10Gbps Ethernet gear. That seems pretty good to me. Which shows that implementers have taken IP fragmentation seriously and put in the hard work necessary to optimize the performance. > Tunnels within a controlled domain may use fragmentation, although it still > will have problems. > Which is why you see most tunnel specifications for controlled domains, state > that the network MTU must be "well managed". We should be able to tunnel within any domain, be it controlled or over the open Internet. Inner fragmentation (with nested encapsulation if necessary) accomplishes that. Thanks - Fred [email protected] > In summary, I don't think the text can say very much more than what it > already does. > > Cheers, > Ole _______________________________________________ Int-area mailing list [email protected] https://www.ietf.org/mailman/listinfo/int-area
