Re: I-D Action: draft-smith-6man-in-flight-eh-insertion-harmful-00.txt

[Brian E Carpenter <[e-mail]>]

One comment at the end:

On 14-Oct-19 11:48, Mark Smith wrote:
> On Sun, 13 Oct 2019 at 21:25, Nick Hilliard <[e-mail]> wrote:
>>
>> Brian E Carpenter wrote on 13/10/2019 01:36:
>>> The packet is too dumb to know anything ;-). My question is how each
>>> node it traverses knows. Indeed, Mark's draft describes a scenario
>>> where the controlled domain argument breaks, because the exit node
>>> might not know that the packet had suffered EH insertion. The
>>> draft-voyer- scenario is not like that, because the affected IPv6
>>> headers are created locally and identifiable as such.
>>
>> the world isn't nearly this pigeonholed though.  The edge around this
>> "controlled domain" that you're implicitly suggesting is sharply-defined
>> is in reality more of a blurry smear.  Think tunnels, leaks, back-doors,
>> "SD-WAN" (whatever that means), policy routing, routed VPNs, etc.
>>
>> If the ietf wants to define a new ipv6-like protocol which is not
>> guaranteed to be interoperable with 8200, there's still space in
>> www.iana.org/assignments/version-numbers to accommodate this :-)
>>
> 
> This is one of the fundamental observations.
> 
>  The trouble is calling this sort of closed/limited domain variant
> that doesn't obey RFC 8200 "IPv6".
> 
> Protocols are more than just packet structures and reserved values,
> they also specify field value rules, interpretations and permitted and
> non-permitted behaviours. All of these latter properties are relied on
> and expected by other implementations.
> 
> I think there are parallels with how human languages work.
> 
> For example, If I define the word "dog" (noun) to mean "wash" (verb)
> within the domain of my house, can I still claim English is being
> spoken in my house? The spelling and pronunciation of "dog" is the
> same, but the meaning of "dog" and where it can be used in sentences
> is different.
> 
> So it isn't English being spoken in my house anymore, even though it
> resembles it, and there is quite a lot of commonality. English
> dictionaries can't be reliably used for any word definitions in my
> house once just one word is redefined. The more words I redefine the
> less applicable the conventional English dictionary is in my house,
> even though the word spellings and soundings continue to be the same.
> 
> This could be solved by calling it "Mark's English" or "Mark's Version
> Of English", which clearly states it is different to conventional
> English dictionary English. There needs to be a "Mark's English"
> dictionary.
> 
> So as Nick said, if the IETF want to have non-interoperable versions
> or variants of "IPv6", then they need different version numbers
> somewhere or somehow - either minor e.g. 6.1, 6.2, or major e.g.
> IPv10.

Be careful what you wish for. It would be easy enough to define a
(probably hop-by-hop) option for this:
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   110xxxxx    |   00000001    | IPv6 version  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    Brian