Comment on The Road Not Taken: A World Where IPv4 Evolved by STrRedWolf

I came across this and had it stewing in the background for a while... and thought "How would this be implemented?" So I pulled RFC 791 (the spec for IPv4) and checked...

Wait, there's options. The protocol itself is extensible. The extra 96 bits per address can be an option... and we'd need two of them, source and destination.

To get a bit deeper, the option byte("octet" in the RFC) would have the copy bit set to 1, the class bits set to represent the value "1" (aka "01"), and the option number be ether 0 for source or 1 for destination address. The option length byte is 96. The remaining address follows. The source and destination options would be required to trigger the advanced routing. No flags needed -- the options are the flag. The "Internet Header Length" field of the IPv4 header would change from 5 to 12 at the minimum.

This makes the protocol a bit more interesting... and maybe worth stealing for my sci-fi books. smiles