Subject: RE: I-D ACTION:draft-savola-ipv6-127-prefixlen-00.txt (fwd)

From: "Michel Py" <[email-masked]>
Date: Wed, 13 Feb 2002 08:51:23 -0800

Pekka, Dale, kre, others,
I consolidated several postings into one....

>>> Dan Lanciani wrote:
>>> An obvious reason would be that the one who wishes to subnet
>>> the /64 is not the same one who should have used a /48, with
>>> the former one having little control over the latter one.

>> Michel Py wrote: 
>> A dial-up connection gets a /48.....

> Pekka Savola wrote:
> No, dial-up connection _should_ get a /48.

Pekka,
You are correct here. Since we are still in the early stages of
deployment, it would be worth fixing it now.

> And also consider e.g. dsl/dial-in internal to the 
> company: they, for practical reasons, must get /64.

> Dale Sesvold wrote:
> This has been going on for quite and while.  And I keep asking
> myself -- Why not /60 for dialups? Its on a nice nibble and gives
> a good handfull of subnets for the SOHO.

Absolutely. If you dial into your company, there is nothing that I
know of that says you must get a /64. The allocation of the SLA
bits is at the discretion of the company's network administrator,
and allocating a /60 to the small number of sick individuals such
as myself that insist on having subnets in their home is perfectly
in line with RFC2373.

> Pekka Savola wrote:
> IMO, 2) adds no complexity.

Poor choice of words. What is the word you would use to qualify
violating RFC2373?

> I hope I made the problems with at least 4) sufficiently clear.

You have. As I said, I find your draft excellent, overall. Maybe a
good canditate for a BCP.

> kre wrote:
> But I dial into my university (and I have a routed net in my house,
> as do many on this list I guess).

That would be interesting to know, actually. I think that most of us
have an overkill setup at home, but I still have a single subnet.
(I actually bridge things such as the ATM PVC to manage the DSL modem
into the main subnet). However, I have an idle ethernet interface
on my router that I will likely make a separate subnet.

> (though very few current dial in users actually get more than /32 -
> just a few of us).

Same idea: These few of you can get a /60. A couple of beers with the
network admin (when it's not you) typically can arrange that. I teach
at University of California, I have my special drop behind the
firewall. Two Fosters. You and I represent 1/1,000,000th of the
population in terms of home setups. We should adapt to that fact,
instead of trying to bend the standards to fit our needs.

> But with a /64 allocated to me, and your theory of subnetting, how
> do I manage to number my house?

With a /64, you don't. And this is the point I am trying to make:
you should get bigger.

> And no, do not tell me to use a switch and a flat network, that
> isn't possible, and even if it were, I wouldn't do it.

Agree, I made that point myself a short while ago.

> Pekka Savola wrote:
> Anyway, I see why people see /126 and such as lucrative: they need
> to assign only _one_ /64 for all point-to-point links.  There might
> be e.g. a couple of hundred of them, and even though 200 of them
> could fit fine to 2^16 subnets, you'd still have to define the
> addressing a bit more carefully.

Actually, I don't see it that way.

The /126 way: 3FFE:BEEF:CAFE:BABE::/64 is the block for p2p links
3FFE:BEEF:CAFE:BABE::/126  link 0
3FFE:BEEF:CAFE:BABE::4/126 link 1
3FFE:BEEF:CAFE:BABE::8/126 link 2
3FFE:BEEF:CAFE:BABE::C/126 link 3

The /64 way: 3FFE:BEEF:CAFE::/52 is the block for p2p links
3FFE:BEEF:CAFE::/64   link 0
3FFE:BEEF:CAFE:1::/64 link 1
3FFE:BEEF:CAFE:2::/64 link 2
3FFE:BEEF:CAFE:3::/64 link 3

Personally, I find the /64 way simpler. In the example above, it eats
1/16th of the /48 and allows for 4,096 links. Organisations with more
than 4,096 links could use /51 or /50 and, if needed, request a /47
or a /46.

Michel.

--------------------------------------------------------------------
IETF IPng Working Group Mailing List
IPng Home Page:                      http://playground.sun.com/ipng
FTP archive:                      ftp://playground.sun.com/pub/ipng
Direct all administrative requests to [email-masked]
--------------------------------------------------------------------

---

From: Robert Elz <[email-masked]>
Date: Thu, 14 Feb 2002 12:20:30 +0700

Date:        Wed, 13 Feb 2002 08:51:23 -0800
    From:        "Michel Py" <[email-masked]>
    Message-ID:  <[email-masked]>

  | Absolutely. If you dial into your company, there is nothing that I
  | know of that says you must get a /64. The allocation of the SLA
  | bits is at the discretion of the company's network administrator,
  | and allocating a /60 to ...

A while ago, you were insisting that everyone get a /48 ... (in this
message you changed from absolute to "should", which is only a minor
variation).

What people get should depend upon their needs.   It should be very
easy to qualify for a /48, but if I don't need that much, and know 
don't need that much, why should anyone force me to take it?

A /60 would do fine for me, that's about my need - a /128 would do
just fine for my mother, that's her need (today anyway) (her system
has no networking devices, other than a modem).

  | Poor choice of words. What is the word you would use to qualify
  | violating RFC2373?

A broken standard.

  | Personally, I find the /64 way simpler. In the example above, it eats
  | 1/16th of the /48 and allows for 4,096 links. Organisations with more
  | than 4,096 links could use /51 or /50 and, if needed, request a /47
  | or a /46.

You missed the main point.   You're still stuck in this mental model
where there are providers, who have short prefix lengths, and other
organisations which get longer ones (/48 .. perhaps /47 or /46 if they're
very big).    There is no such distinction, at some level, everyone is
a provider - and attempting to force things into some model where they're
not is simply absurd.    I don't want to have to go running to APNIC (or
ARIN or RIPE in other parts of the world) and try to justify getting a /35
or whatever their base (smallest) allocation is at the time, just because
I want to connect a few friends and family to my house (thus becoming
their ISP).

Once again, all we need here is the most flexibility we can have, no
built in assumptions about what is required to be a boundary (and to
simply ignore any noise in any docs which claims there is such a thing).

If we do that, and if we keep on having autoconf on the most common networks
assuming it has a /64 to play in (leaving anyone wanting to use such a net
requiring at least a prefix that long) and the world will sort itself out.

kre