On 12/20/2012 03:04 PM, Templin, Fred L wrote: >> On 12/18/2012 04:13 PM, Templin, Fred L wrote: >>> I have a question about this document. Is a middlebox permitted >>> to fragment an "atomic" fragment before forwarding the packet >>> on to the next hop? If not, why not - after all, that's why the >>> host inserted the fragment header in the first place. >> >> My take is that an *IPv6* middle-box is not permitted to fragment the >> packet. The IPv6/IPv4 translator is, from an IPv6 point of view, a >> host/end-point/end-system (that's where the v6 world ends for that >> packet). > > On further thought, I don't fully accept the notion that the > translator is a host/end-point/end-system.
>From the pov of the IPv6 network that's where the packet "ends". > The IPv6 host provides > the translator with an Identification value, and that value carries > forward into the IPv4 world. So, while the IPv6 packet itself does > not carry forward, IPv6 information does. Yes and no -- e.g., you cannot use the full 32-bit Frag ID. >> As to the "why not", I'd guess the reason is "only IPv6 hosts fragment >> packets" > > I think there would need to be an asterisk next to that statement > saying that IPv6/IPv4 translators are exempt from this requirement. > And, if the translator can be exempt then so also should an IPv6 > middlebox that connects to a link that would otherwise be obliged > to perform burdensome link adaptation. This does not only apply to tunnels. One could think of some radio devices, embedded systems, etc., for which an adaptation layer would possible be overkill. -- So you're idea sounds, at least in principle, sensible to me. I will review your I-D and will come back with some feedback. Thanks! Best regards, -- Fernando Gont SI6 Networks e-mail: fg...@si6networks.com PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492 -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
