[ale] IPv6 Subnetting

[Michael H. Warfield]

On Tue, 2011-02-15 at 12:56 -0500, Michael B. Trausch wrote: 
> On Tue, 2011-02-15 at 12:14 -0500, Michael H. Warfield wrote:
> > Don't go there if you can avoid it.  We want to avoid IPv4 mind think
> > here.
> > 
> > If you need more than one subnet, you're suppose to get a larger
> > allocation and the ISP should make one available.
> > 
> > Per the standards...
> > 
> > If you need 1 subnet you get a /64.  If you need more than one subnet,
> > you should get a /48 but some ISPs such as freenet6 may break that
> > down further and hand you a /56 which is still 256 subnets.  Yes, most
> > ISPs should be handing you a /64 as a default.  That is per the
> > standard if that's all you need and that will be the case with most
> > residential customers.  If you need more, they should allocate you
> > more or they are in violation of the standards. 

> Oh, indeed.

> That said, I can imagine that there will be lots of ISPs that won't even
> know how to handle such a request.  Hell, there are now, for IPv4, and
> we've been running that for decades.

There's one major difference.

With IPv6 they already have to allocate you a routable network, even if
it only has 1 subnet.  That's a /64.  It's not like allocating a single
address with IPv4 and then you have to change the paradigm to a
"routable subnet" the moment you allocate a block of addresses.  We've
already crossed that threashold and now we're just haggling over the
block size.  One would hope that these guys wouldn't be so penny ante
that they don't have some corporate customers who will require multiple
subnets, so they should have some clue as to how to deal with that and
allocate it as well.  Look at some of the other threads on this list
where people have gotten business calls v4 with multiple addresses and
dealt with routers they can't "open" because the ISP won't let them.
Tell you what.  We're all now in the same class.  Maybe they'll call it
business class if you have more than one subnet.  Wouldn't surprise me
but the reality is, it's only the bits in the subnet.  You're not
changing your allocation infrastructure from single address based to
routed subnet based.  You're there either way.  That gives me some hope
for optimism (note line in my signature).

> I plan on testing a setup like what I described, just for the sake of
> verifying that it all works.  In theory, it should.  Of course, it
> screws up a lot of the automatic help and thus convenience... and it
> might even make things break that expect to never see something greater
> than a /64.  There are a number of IPv6 calculators out there on the net
> that simply absolutely insist that it's not possible to have a network
> with more than 64-bits in the prefix.  I would not be surprised if there
> are such assumptions in application software or network stacks.
> 
> 	--- Mike

-- 
Michael H. Warfield (AI4NB) | (770) 985-6132 |  mhw at WittsEnd.com
   /\/\|=mhw=|\/\/          | (678) 463-0932 |  http://www.wittsend.com/mhw/
   NIC whois: MHW9          | An optimist believes we live in the best of all
 PGP Key: 0x674627FF        | possible worlds.  A pessimist is sure of it!
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 482 bytes
Desc: This is a digitally signed message part
Url : http://mail.ale.org/pipermail/ale/attachments/20110215/6d14545b/attachment.bin