On Fri, 2016-04-01 at 22:16 -0400, David Miller wrote: > From: Alexander Duyck <alexander.du...@gmail.com> > Date: Fri, 1 Apr 2016 12:58:41 -0700 > > > RFC 6864 is pretty explicit about this, IPv4 ID used only for > > fragmentation. https://tools.ietf.org/html/rfc6864#section-4.1 > > > > The goal with this change is to try and keep most of the existing > > behavior in tact without violating this rule? I would think the > > sequence number should give you the ability to infer a drop in the > > case of TCP. In the case of UDP tunnels we are now getting a bit more > > data since we were ignoring the outer IP header ID before. > > When retransmits happen, the sequence numbers are the same. But you > can then use the IP ID to see exactly what happened. You can even > tell if multiple retransmits got reordered. > > Eric's use case is extremely useful, and flat out eliminates ambiguity > when analyzing TCP traces.
Yes, our team (including Van Jacobson ;) ) would be sad to not have sequential IP ID (but then we don't have them for IPv6 ;) ) Since the cost of generating them is pretty small (inet->inet_id counter), we probably should keep them in linux. Their usage will phase out as IPv6 wins the Internet war...
