[CUWiN-Dev] IPv6 -- TAKE II: NEED ANSWER BY TUESDAY NOON...

[David Young]

On Thu, Apr 21, 2005 at 03:04:52PM -0500, Sascha Meinrath wrote:
> Hi all,
> 
> The ongoing quest for IPv6 space continues (and is going quite well). 
> For the past year or so I've been working to get a block of IPv6 space for 
> CUWiN (in particular), Community Wireless Networks, and Community Networks 
> in general.  Free Press has come on board to help create a 
> process/structure that'll make it possible to get a /32 for the endeavor 
> and mainstain the system necessary to make it all work.
> 
> We had a discussion about this on the old -dev list beginning August 30th 
> of last year.  It would be great if we could revisit the discussion and 
> formulate a techical solution for ad-hoc networks to utilize a /32 to 
> ensure unique IPs for devices.

I think it will be hard to put a request for a /32 on a sound technical
basis now as it was in August.  It seems to me that the numbers are
not what you are really after.  What you want is a process by which the
numbers can be had inexpensively or free.  Perhaps I am mistaken.

Several words on the technical basis:

A /32 is not necessary or sufficient to ensure unique IPs.  The way that
we will ensure unique IPs is by duplicate address detection/avoidance.
In the long term, we cannot avoid DAD/DAA on ad hoc networks, be they
IPv4 or IPv6 networks.

There are promising IPv4-to-IPv6 transition protocols available for us
to use.  For example, anybody with a routable IPv4 address can get a
/48 using "6to4."  An IPv4/IPv6 host that is stuck behind a NAT firewall
can make IPv6 connections using "Teredo."  Some of these protocols are
showing up in mainstream operating systems: I believe Windows XP already
has both 6to4 and Teredo capabilities, and Mac OS X has 6to4.

One idea we have bandied about is IPv6 multihoming and
provider-independence.  I don't think a /32 helps us here.  One thing
about IPv6 that seems settled is that provider-based addressing is "in,"
and geographical addressing is "out."  In the multi6 working group's
conception of v6 multihoming, each host in an N-homed networked will have
N addresses assigned, one from each provider's prefix.  Through some
protocol to-be-defined, a multihomed host will tell its peers when it
changes from one provider's to another's prefix.  It's all pretty vague,
but it doesn't involve provider-independent addresses.

There is such a thing as an "experimental" prefix.  You can get these for
a limited time only, I think.  Microsoft has one for Teredo (see above).
I think it is appropriate to experiment with 6to4 and Teredo before
getting a new experimental allocation, though.

Enough about the technical stuff.  About price: 6to4 and Teredo addresses
for the v4->v6 transition period are "free."  To predict CUWiN's costs
for provider-assigned IPv6 addresses might be hard, since there are no
IPv6 providers in Champaign-Urbana.  You might have to go as far away
as Europe or Asia to find out the going rate for IPv6 numbers.  It may
be pretty reasonable, already.  I have a feeling that the price will
go down as the number authority's IPv6 experience increases and their
book-keeping overhead decreases.

Dave

-- 
David Young             OJC Technologies
dyoung at ojctech.com      Urbana, IL * (217) 278-3933