[ih] fragmentation (Re: Could it have been different? [was Re: vm vs. memory])

[Dave Crocker]

So, I see that I've touched a nerve.  I'd expected to touch one, but not 
this one.  I'll try to respond carefully; please be gentle, as I fail...


On 10/26/2017 3:36 PM, Paul Vixie wrote:> Dave Crocker wrote:
>> The original mandate was for more address space. All the other
>> 'features' that were attempted went beyond that mandate.
> 
> that word, "mandate," i don't think it means what you think it means.

Of course I do, and it's purely luck that Craig made the point for me: 
cf, RFC 1726.  That was not produced quickly nor in isolation nor by 
only a tiny collection of wayward folk.  It creates a mandate to work on 
a particular problem to a particular goal.

My point is that this was expanded over time.

In effect, the goal became "let's reinvent IP was lots of ambitious 
features" and that's a story template that never ends well.  Or, in this 
case, possible at all.

(I haven't re-read it from when it was developed by my recollection is 
that even it was more ambitious than was needed, but that's just my 
rogue opinion.)

While I realize that fragmentation was your starting point, my comments 
were not meant to be about that one way or the other.

(However I'd had the impression that even IPv4 fragmentation is 
problematic these days, so am surprised it's an issue for v6; but really 
my comments were meant as broadly as the language indicates and not at 
all about a particular like this.)


> we were volunteers, who worked on what we found deserving of our time.

(We can deal with the deceptive IETF myth of 'volunteer' some other time.)

The essence is that, yes, a 'strongly dominant' set of those working on 
IPv6 chose to expand the scope beyond the original intent of the effort, 
namely to simply expand the address space.  My claim then and now is 
that that greatly facilitated the problematic history that ensued.


> if the fragmentation differences between v4 and v6 were as you say a
> form of scope creep, 

but I didn't say that and I apologize for, apparently, not being clear 
that my comments were not at all meant about fragmentation per se. 
Simplistically, since v4 has fragmentation and had a really good reason 
for needing it, I'd expect v6 to have it, absent a really good reason 
not to.


> i was pushing for a simple expansion of the IP header so that we could
> use source routing on all flows, to connect network 10 at each end,
> through a series of tubes, really, that had unique IP addresses, so that

That's an amusing specific, for me.  There was a meeting with Vint and 
others discussing the challenge of testing IPv6, given that there was no 
test lab large enough to make for an interesting case, and I suggested 
tunnelling IP(v6)/IP(v4) to connect an aggregation of test labs.  Vint 
did not initially like the idea though I gather this changed over time.


> the path would become the identity. the dns portion of this design
> looked a lot like what was later called 8+8. i was shouted down, as was
> mike o'dell, so i harken to your suspicion that anything simple would've
> been rejected.

cf my earlier posting that proposed taking alternative numbering scheme 
out of the critical path for adoption.

At the time the topic of numbering had quite a lot of theory and 
research proposals -- often with a great deal of personal fervor, but 
without much detail to back them up or appreciation that they were 
theory, not practice.


d/
-- 
Dave Crocker
Brandenburg InternetWorking
bbiw.net