[131414] in North American Network Operators' Group
Re: IPv6 fc00::/7 ??? Unique local addresses
daemon@ATHENA.MIT.EDU (Owen DeLong)
Sun Oct 24 10:09:10 2010
From: Owen DeLong <owen@delong.com>
In-Reply-To: <20101024134857.GA41659@ussenterprise.ufp.org>
Date: Sun, 24 Oct 2010 07:04:42 -0700
To: Leo Bicknell <bicknell@ufp.org>
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Oct 24, 2010, at 6:48 AM, Leo Bicknell wrote:
> In a message written on Sat, Oct 23, 2010 at 05:23:14PM -0700, Owen =
DeLong wrote:
>> On Oct 23, 2010, at 8:03 AM, Carlos Martinez-Cagnazzo wrote:
>>> On Fri, Oct 22, 2010 at 11:38 AM, Leo Bicknell <bicknell@ufp.org> =
wrote:
>>>> There are some folks (like me) who advocate a DHCPv6 that can =
convey
>>>> a default gateway AND the ability to turn off RA's entirely. That
>>>> is make it work like IPv4.
>>>>=20
>>> I'd also love to turn off stateless autoconfig altogether and not be =
coerced
>>> to assign /64s to single LANs, which I am becoming convinced that it =
was a
>>> poor decision on the IETFs part.
>>>=20
>> Nah... The /64 thing is fine. If they hadn't done that, we likely =
would have only
>> a 64-bit address space total. 64-bit lans with 64-bit routing =
identifiers are
>> fine.
>=20
> I think the 64-bit boundry is fine (from a DHCP perspective). I
> do think if we're going to update the DHCP spec it should support
> a netmask option, just because leaving it out is short sighted to
> the future, but I would use it with /64's today.
>=20
My understanding was DHCPv6 did support prefixes other than /64.
>> There really is no need for anything smaller than /64. What, =
exactly, do you
>> think you gain from a smaller netmask?
>=20
> There is a slippery slope here, if users make do with smaller
> providers may give out smaller blocks, and so on.
>=20
Yeah, that could be worse than neutral. Still there's no gain to smaller
than /64, only loss...
> That said, if a provider does hand out a /64, I would very much
> like technology to make 16 bits of subnet + 48 bits of host, with
> EUI-48 used directly for autoconf as an option. Particularly when
> we talk about 6rd and other things that use a lot of space this
> option would be huge. Users would still get 16 bits of subnet, and
> host space so big they could never fill it.
>=20
I think that ship has pretty well sailed, but, it might be a good future
workaround if providers start doing stupid pet tricks like assigning
single /64s to end customers.
Owen
