> From: [email protected] [mailto:[email protected]] On Behalf Of Brian > E Carpenter
> On 10/07/2013 05:28, RJ Atkinson wrote: > ... > >> But for one problem: adaptation layer fragmentation is > >> *transparent*, so there is no way for an application > >> to do the equivalent of PMTUD to avoid/minimize adaptation > >> layer fragmentation. > > > > Good point. > > And you can't get round it. The decision to raise the minimum link > MTU from 576 to 1280 was not a change in principle; it was just > raising the level at which transparent adaptation layers were > presumed to be acceptable. The big change in principle was the > abolition of on-path fragmentation. I'm not sure I follow this. First is, the change of MTU was not one of 576 to 1280. It was one of 64 to 1280. That 576 figure is the smallest maximum RECONSTITUTED packet size that IPv4 is supposed to support. Individual fragments need not be larger than 64 bytes. If that same principle had been applied to IPv6, maybe we wouldn't be having these discussions at all. The other point is, I don't see how transparent adaptation layers are an issue at all? I don't think anyone is saying that it's impossible to transmit IPv6 over ATM cells? Or are they? Bert -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
