Hello again, Fernando, > -----Original Message----- > From: Fernando Gont [mailto:fg...@si6networks.com] > Sent: Tuesday, December 18, 2012 12:00 PM > To: Templin, Fred L > Cc: draft-ietf-6man-ipv6-atomic-fragme...@tools.ietf.org; 6man WG > Subject: Re: AD Evaluation: draft-ietf-6man-ipv6-atomic-fragments > > Hi, Fred, > > 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. 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. > 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. Thanks - Fred fred.l.temp...@boeing.com > > If so, > > then shouldn't the draft say something about the permissible > > behavior of middleboxes when forwarding an "atomic" fragment > > (e.g., "a middlebox is permitted to perform fragmentation on > > an "atomic" fragment before forwarding to the next hop")? > > Why should there be a difference between fragmenting an atomic fragment > and e.g. re-fragmenting a non-atomic fragment? > > 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 --------------------------------------------------------------------
