Re: draft-narten-ipv6-3177bis-48boundary-02.txt

[Mark Smith <ipng@69706e6720323030352d30312d31340a.nosense.org>]

Hi,

Following on from Jordi's comment,

> In addition, as an end user, it provides a recommendation to ISPs to provide
> a reduced service in terms of the number of subnets, instead of the actual
> /48 recommendations (with a clear example for /56), which I think is very
> bad, especially when it is based in a subjective view of "excessive".

although I haven't had a chance yet to read the new draft quite yet, I
think pointing out the following paper might be worth useful as it
discusses the motivations behind a similar addressing decision from the
past (from when I was a young lad of 10!) :

http://portal.acm.org/citation.cfm?id=802680&coll=portal&dl=ACM&CFID=76839379&CF
"48-bit Absolute Internet and Ethernet Host Numbers",
Yogen K. Dalal and Robert S. Printis, 1981.

It seems to me that the fundamental decision here is the choice or
balance between conservation and convenience. With a scarce resource,
you need to make conservation a priority, which of course is what (now)
happens with IPv4. With an abundant resource, such as Ethernet
addresses, or IPv6 addresses (and IPv4 addresses for most of the
classful days), you can make (operational/deployment etc.) convenience
a priority, with the cost of that convenience a higher level of
consumption of the resource. This additional consumption isn't "waste",
because it provides a direct and useful benefit. However, if you apply
a scarce resource usage mentality (which is the IPv4 one these days), it
would appear to be, because "convenience" is basically a luxury, not a
necessity.

Obviously, in both the scarce or abundant cases you need to make sure
actual waste doesn't occur.

While I do agree that a /48 per site does seem excessive, particularly
for a home user, and would therefore accept the /56 per site argument,
I think it is very important that the balance isn't isn't tipped too far
back towards conservation when it isn't necessary.

I think one of the fundamental goals of IPv6 is convenience of use and
administration, and I also think it is one of the fundamental benefits
over IPv4. If we have opportunities to make anything in IPv6
convenient, such as renumbering without changing subnet numbers, at the
the cost of some of the abundant IPv6 address space, I think it is a
worthwhile cost.

Regards,
Mark.

(Another curious (amusing ?) example of "waste" we're quite happy to
accept for the convenience or cost benefit is the 12 byte per
packet overhead for addressing on 10GigE point-to-point links, where
addressing isn't actually necessary at all.)