Subject: Re: How the IPnG effort was started

From: [email-masked] (Noel Chiappa)
Date: Wed, 17 Nov 2004 06:55:38 -0500 (EST)

> From: Brian E Carpenter <[email-masked]>

    > You might explain that to the people who say they need IPv6.

OK, I'll bite.

Let's assume what many people now seem to concede, which is that a large part
of the Internet is going to continue to be IPv4-only. So, what's the
functional difference between:

- A host which has an IPv6 only address, which it cannot use (without
"borrowing" a global IPv4 address) to comunicate directly with IPv4-only
hosts out on the global Internet.

- A host which has an IPv4 local-only address, which it cannot use (without
"borrowing" a global IPv4 address) to comunicate directly with other IPv4
hosts out on the global Internet.

	Noel

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From: Jeroen Massar <[email-masked]>
Date: Wed, 17 Nov 2004 13:14:21 +0100

>     > You might explain that to the people who say they need IPv6.

Grawl back ;)

> hosts out on the global Internet.

Difference is that the IPv6 host can actually communicate end-2-end
globally and not only in it's local network.

It is all about *global* communication, not about local communication,
you can avoid IANA completely in those cases, simply use 1.2.3.4 as an
IP at your convenience, you will have enough 32-bit space then, but you
cannot talk to your sister on vacation on japan using VoIP who you
really do not want to explain what a NAT box is and how she can get
through it with a VoIP tunnel tool or other VPN tricks.

Before you argue "but there is no IPv6 global connectivity yet", then
please check your local Abilene site, with that nice government funded
Internet2 and you will find quite a lot of activity there. Asian and
European regions are much further in deployment. Not to the doorstep of
most houses yet in Europe as they do in Korea and Japan, but with the
aid of TunnelBroker systems one can get a long way already and these are
also available on your side of the pond of course ;)

Greets,
 Jeroen

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From: Brian E Carpenter <[email-masked]>
Date: Wed, 17 Nov 2004 13:39:53 +0100

Noel Chiappa wrote:
> of the Internet is going to continue to be IPv4-only.

No, what is conceded is that a large part of the Internet will continue
to be IPv4 only *for a number of years*. Slightly different statement.

 >  So, what's the

Not much, in terms of available applications. But an IPv6 host which only
wants to talk to other IPv6 hosts can perfectly well do so over the IPv4
network, and it can talk to dual stack servers over the IPv4 network. There
really is a creeping deployment model here. Technically, that is capable
of reducing IPv4 to a legacy. Whether it does so or not will be unclear
for a number of years. We are only ten years into the IPv6 adventure
(counting from the Toronto IETF). It's too soon to tell.

     Brian

---

From: Harald Tveit Alvestrand <[email-masked]>
Date: Wed, 17 Nov 2004 13:52:29 +0100

--On 17. november 2004 06:55 -0500 Noel Chiappa <[email-masked]> 
wrote:

> Let's assume what many people now seem to concede, which is that a large
> part of the Internet is going to continue to be IPv4-only. So, what's the
> - A host which has an IPv4 local-only address, which it cannot use
> (without "borrowing" a global IPv4 address) to comunicate directly with
> other IPv4 hosts out on the global Internet.

that the former can communicate with all other nodes with globally 
reachable IPv6 addresses, without having to borrow a global IPv4 address to 
do so?

I'll leave it as an exercise for the reader to figure out whether this is a 
*significant* functional difference - but it *is* a functional difference, 
and that was what you asked for, Noel....

---

From: shogunx <[email-masked]>
Date: Wed, 17 Nov 2004 03:43:55 -0500 (EST)

On Wed, 17 Nov 2004, Harald Tveit Alvestrand wrote:

The difference has been significant on my end.  The advantage of end-to-end
connectivity to/from hosts previously only behind a NAT is remarkable.  So
is ALL THE ADDRESS SPACE that I now have available, without extra charges
from the local telco/cableco.  I don't think that I am ready to give up on
v6 deployment across the entire internet just yet... these things take
time.

Scott

> and that was what you asked for, Noel....

sleekfreak pirate broadcast
http://sleekfreak.ath.cx:81/

---

From: Robert Elz <[email-masked]>
Date: Thu, 18 Nov 2004 10:17:54 +0700

Date:        Wed, 17 Nov 2004 06:55:38 -0500 (EST)
    From:        [email-masked] (Noel Chiappa)
    Message-ID:  <[email-masked]>

  | Let's assume what many people now seem to concede,

"concede" is a very poor word choice, "predict" perhaps, but more
probably, and more accurately, "hope", or even "pray".

  | which is that a large part of the Internet is going
  | to continue to be IPv4-only.

It simply cannot be.   Either it dies (or atrophies, which is
essentially the same thing), or IPv4 is replaced by something.

No matter what we do, there is not enough IPv4 address space for
the core network to use to reach future end sites.   Even if you
take the very best assumptions, assume we switch back to flat routing
(no more addresses lost to hierarchy), and we can cope with that,
and we assume we recover *all* the currently assigned portable
address blocks (the /8's that MIT, Stanford, etc all have), the /16's
that almost everyone who's been around for more than 15 years has,
and even all the /24's that are still being assigned today, and
allocate organisations (including ISPs and everyone else who currently
believes they qualify for more) all /28's, and flat route those, there
still aren't enough /28's available to number everyone who is going to
want to be numbered.  Switch to /29 and it doesn't make a difference.
Get to /30 and just maybe, depending on demand into the future from
the currently under-developed countries - but that's not enough for
a site to provide any kind of reasonable service (can't have adequate
backup servers and such).

And, of course, those are absurd assumptions (flat routing /28 indeed!)

The core network, the part that needs to be able to identify end
sites, simply needs more addresses - and there's no way to fake it
via layers of NAT, end nodes from any random point on the net still
need to be able to indicate that it is my site (forget even about host),
and not yours, that they want to contact.   That means that we have
to have different addresses (identifiers).   IPv4 simply cannot last.

Of course, end user sites could keep using IPv4, and use something
like NAT to translate, to whatever the code network is using.   And
for a while, no doubt some will continue.   But why would that do
that indefinitely, it makes no sense?   The translation is just an
extra cost/management burden that they don't really need - after all,
all (at least if it is IPv6 that the core switches to), all the
end-user equipment that counts already supports IPv6, switching end
sites now is easy (and relatively painless).

Whether what the core switches to is IPv6, or something different
can't be concluded with certainty of course, but the "we don't need
to change from v4, ever" attitude is simply absurd.   The timeframe
when a switch will finally be mandatory, rather than simply a
plausible choice, is also not yet certain.   But there's no way
to pretend that something isn't coming.   We knew that back in 92.
Nothing has altered to change that reality - if anything, back then
the endemic nature of the net wasn't yet certain, so then it was
possible that the net would in reality never grow big enough to
outgrow v4.   Now (again, unless the net dies) that's no longer an
option.

So ...

  | So, what's the functional difference between:
  | 
  | - A host which has an IPv6 only address, which it cannot use (without
  | "borrowing" a global IPv4 address) to comunicate directly with IPv4-only
  | hosts out on the global Internet.
  | 
  | - A host which has an IPv4 local-only address, which it cannot use (without
  | "borrowing" a global IPv4 address) to comunicate directly with other IPv4
  | hosts out on the global Internet.

short term, of course, nothing.   But the former has the possibility,
even expectation, of the "borrowing" simply ending, most likely even
in the not too distant future (though certainly beyond the end of the
financial year, and so way out of scope of many people's thoughts...)

kre

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From: "Stephen Sprunk" <[email-masked]>
Date: Fri, 19 Nov 2004 13:53:19 -0600

Thus spake "Robert Elz" <[email-masked]>
> essentially the same thing), or IPv4 is replaced by something.

It is possible that hosts with existing IPv4 connectivity will continue to 
use it and never upgrade to IPv6 -- only new hosts would use the latter. 
With NAT, it's possible that many end sites (even new ones) may use IPv4 
internally and NAT to IPv6 for external communication.

IPv4 is dead.  Long live IPv4.

> the core network to use to reach future end sites.

Arguably there is not enough IPv4 address space to meet current needs, but 
we're hiding that problem with the use of NATs.  Some places are so starved 
for addresses they're even using multiple layers of NATs.  Good luck 
figuring out how many IP-connected hosts are really out there now; I doubt 
it's up to a billion yet, but it'll probably be there soon (and 25% 
efficiency is the norm for IPv4).

The future is obviously bad for IPv4, as it doesn't even have enough 
addresses for each human on the planet, much less for the dozens of 
"connected" devices per person that have been theorized.

> And, of course, those are absurd assumptions (flat routing /28 indeed!)

Why mess with /28s?  If we're going to mess up routing, we might as well 
assign /32s to each host and route those.  Nope, still not enough addresses.

> to have different addresses (identifiers).   IPv4 simply cannot last.

That's why several years ago we moved from just the IP identifying the host 
to using port numbers as well (aka NAT).  2^48 hosts is doable, though 
messy.  Oh, and that doesn't include the hosts that aren't talking 
externally and thus don't use any address+port resources at all...

> sites now is easy (and relatively painless).

The cost of IPv4 NAT is apparently perceived to be lower than the cost of 
IPv6 and 6to4.

> financial year, and so way out of scope of many people's thoughts...)

The former does have an obvious path to a full IPv6 deployment, but (a) 
there is a serious "first mover" problem, and (b) the costs of taking that 
path will be paid twice.

Even now, with Windows finally supporting IPv6, it's still tough to find 
SoHo/consumer FW devices that will pass IPv6 traffic (even tunneled) and 
many corporations are forced with swapping out every L3 switch they own to 
get models that support IPv6.  There is substantial economic cost to the 
former scenario over the latter today, even before you calculate the 
training cost of millions of MCSEs and CCNAs that don't know anything about 
IPv6 and see no reason to learn.

I predict things will continue roughly as they are now, and when the IPv4 
space is approaching true exhaustion the prices of PI and PA space will rise 
so much that it will exceed the cost of converting to IPv6.  Then IPv6 will 
take off, and not before.

S

Stephen Sprunk         "God does not play dice."  --Albert Einstein
CCIE #3723         "God is an inveterate gambler, and He throws the
K5SSS        dice at every possible opportunity." --Stephen Hawking