> On Apr 17, 2021, at 9:49 PM, Phillip Hallam-Baker <phill@xxxxxxxxxxxxxxx> wrote:
>
> IPv6 isn't actually a 'protocol' as such.
It might be useful to provide your definition of a protocol...
> It is merely a data structure.
You have described the messages only, which alone has never been enough to define a protocol.
Usually that is the case. But IP is a rather peculiar exception. There is lots of stuff above and lots of stuff below and there is the routing layer out to the side. But what is there to the packet layer except the packet format and the rule that you take a packet from the input port, decrement a counter and pass it to the output port.
See the note I posted to Stephanie. There is a LOT there beyond just counter decrement.
Just because a separate mechanism populates the forwarding table also doesn’t override the longest-prefix nature of that table, nor that it includes both outgoing interface and next-hop IP. How far is it possible to move from that approach and still be doing packet data? You can change the selection of which packet is chosen to pass next or affect the pass/drop rules.
Yes, you can change the order - but that’s because IP is defined as not preserving order. You can drop - because IP does not guarantee delivery. That doesn’t undo the many other rules that are still followed.
You can redefine the bits’ behaviors and meanings, but that would be defining a new protocol, at which point there’s little utility if any in keeping the bit patterns the same.
My point is simply this: what is it that cannot be done within the constraints of IPv6 would motivate a new protocol?
Simply put, take anything IPv6 requires and change it. No RA. No ND. No longest-prefix match. Different address locations or bit meanings within those addresses. Basically, take everything that is IPv6 and undo it. We keep having people coming along making these suggestions for IPv8, IPv10, etc. etc. and the inventors never once seem fit to ask what is so different about their proposal it can't be done in IPv6.
It’s definitely fair to ask “is there a way to do what you want within the IPv6 protocol”, or, for that matter, any other existing protocol (GRE, IPsec, etc.).
The whole point of the Internet is the narrow waist is really simple.
There are many “whole points” to the Internet. Globally unique addressing, local forwarding decisions with global impact, packets that can’t circulate forever, finite but variable length messages, etc. Narrow waist is only one of those points.
Joe
|
