Subject: RE: I-D ACTION:draft-narten-ipv6-iana-considerations-00.txt

From: "Michel Py" <[email-masked]>
Date: Thu, 24 Oct 2002 14:39:31 -0700

Thomas,

> Thomas Narten wrote:
> [192.0.2.0/24]
> This is far less than is needed (strictly speaking) to
> document usages that require shorter prefixes. But I'm
> not aware of this being a problem in practice.

Because there is a solidly established practice of using RFC1918
addresses for documentation purposes, especially the 10. net.

> I think what we want here is a workable balance between
> no addresses for documentation at all and allocating too
> much space in order to document all possibilities.

I agree. A compromise between wasting too much space and a futile
attempt to preserve what does not need to.

>> Then a /32 is not enough, IMHO. A /32 is the size currently
>> allocated to LIRs; imagine a sample BGP config that involves
>> three LIRs, you would need at least three /32s. A /30 would
>> be what I consider the bare minimum in this case.

> But can't the same then be said for a 192.0.2.0/24 not
> being long enough in IPv4?

Yes, but the situation is not the same: there is no shortage of IPv6
addresses. It's not a reason to waste them, but while assessing this
balance we are talking about, ask yourself this question:

With the current allocation size for LIRs (/32) there could be 500
million (2^29) LIRs. Is it worthwhile allocating 4 out of these 500
million for documentation purposes? I think so.

Michel.

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From: Alain Durand <[email-masked]>
Date: Thu, 24 Oct 2002 16:05:49 -0700

>addresses for documentation purposes, especially the 10. net.
Bingo!
We need to reserve some equivalent space in v6 land.
Net 10 allows 16 bits to create a hierachy of /24,
so we need 16 bits in v6 lands to create a hierachy of /48.
That translate into a /32.

    - Alain.