Re: I-D Action: draft-carpenter-6man-lap-00.txt

[Mark Smith <[e-mail]>]

On Fri, 15 Jun 2018 at 06:21, Fernando Gont <[e-mail]> wrote:

> On 06/14/2018 10:24 PM, Mark Smith wrote:
> >     > Nick, while I agree with you, you are basically making Lorenzo's
> >     point,
> >     > this just degrades into a rehash of RFC4291-bis.>
> >     > So, would someone from Lorenzo's camp please propose language that
> >     > rationalizes RFC6164 with the 64-bit IIDs of RFC4291.
> >
> >     Rationale: Folks realized that there are reasons for which you might
> do
> >     LAP != 64. -- which is not a surprise, since the rationale for the
> >     specific "64" value is simply "historical reasons".
> >
> >
> > And proven simplicity, proven by other protocols developed in the 1980s,
> > and deployed in the 1990s.
> >
> > IPv4 was a terrible protocol to understand and deploy compared to IPX
> > and AppleTalk. They just worked. (My first protocol was IPX, when
> > leaning IPv4 the fundamental question I wondered was "Why is this so
> > hard and complicated?" Then I taught it. That took 5 attempts before I
> > fully felt happy with how I'd taught and explained IPv4 addressing - and
> > that didn't even cover CIDR.)
>
> People usually ask the same question about IPv6. Example: compare ARP +
> DHCP with ND + combo(SLAAC/DHCPv6)
>
>
No where near as complicated as IPv4 Classful / subnet/ variable length
subnet / CIDR addressing.

People could ask the same reason why there are 7 layers in the OSI
reference model, rather than just one. The answer is the same.

Besides, you don't *need* to use subnet sizes != 64. If you lie /64,
> nobody will force you to do something else.
>
>
There's a lot of things we don't need.

We didn't "need" ARP, we could have manually loaded each host with static
MAC address to IP address mapping tables.

We didn't need DHCPv4 or BOOTP/RARP either. All those settings were
possible to set manually on each host too.

We don't "need" dishwashers or washing machines, we could have continued to
manually wash our dishes and clothes.

Many of our technologies are fundamentally optional, however they make our
life simpler and cheaper and that is why we design, build and use them.

In IPv4 we needed variable length edge subnets/prefixes (and Classes and
all the other things that preceded CIDR) to continue to be able to use IPv4
within its fundamental constraint of 32 bit addresses. We don't need them
in IPv6.


> > Those 1980s protocols' usability, supportability and deployability
> > levels are the ones I expect IPv6 to meet and exceed, not IPv4's.
>
> With fixed length IID's, host willing to extend the network further and
> further will be forced to do NAT.
>
>
If any host can't get an IPv6 address from the network (and more than one
per BCP204), then the IPv6 deployment and IPv6 network is broken, because
the fundamental reason for IPv6 - many many more addresses than IPv4 -
isn't being achieved. Continue to use IPv4(+NAT), or give up and tell the
user the network is broken.

We need to stop trying to reduce IPv6's functionality to IPv4's to suit
those who don't really want to learn to think in IPv6 (by recreating
address scarcity when it isn't necessary, that is creating artificial
address scarcity).

Regards,
Mark.



> --
> Fernando Gont
> SI6 Networks
> e-mail: [e-mail]
> PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492
>
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