On October 6, 2019 at 15:18 mpal...@hezmatt.org (Matt Palmer) wrote: > On Sat, Oct 05, 2019 at 04:36:50PM -0400, b...@theworld.com wrote: > > > > On October 4, 2019 at 15:26 o...@delong.com (Owen DeLong) wrote: > > > > > > OK… Let’s talk about how? > > > > > > How would you have made it possible for a host that only understands > > 32-bit addresses to exchange traffic with a host that only has a 128-bit > > address? > > > > A bit in the header or similar (version field) indicating extending > > addressing (what we call IPv6, or similar) is in use for this packet. > > How does that allow the host that only understands 32-bit addresses to > exchange traffic with a host which sets this header bit?
As I said, it doesn't, but it lets each host decide that rather than the router tho if the host just knows enough to copy out the entire src/dst address (imagine the bits beyond the first 32 were in something like an extended ICMP options field w/in the IP header) then the rest could operate identically to ipv4. So all you'd need added to a host IPv4 stack would be if you see this extended addressing flag/bit/whatever then there's more that needs to be copied out to each outgoing IP packet. It would be the routers' job to interpret those extra bits for routing. -- -Barry Shein Software Tool & Die | b...@theworld.com | http://www.TheWorld.com Purveyors to the Trade | Voice: +1 617-STD-WRLD | 800-THE-WRLD The World: Since 1989 | A Public Information Utility | *oo*