ISP DHCPv6 and /48

Baldur Norddahl baldur.norddahl at gmail.com
Fri Jul 10 10:34:49 UTC 2015


On 10 July 2015 at 12:09, Mark Andrews <marka at isc.org> wrote:

>
> Who is forbidding you?  Not the IETF.  Not the RIRs.
>

RIPE policy requires me to send in justification for review for any
allocations larger than a /48. For a $35/month contract? Forget it, not
going to happen. Plus it would be rejected.

Just have them deploy a IPv6 router and configure it to brigde IPv4.
> As far as the existing clients are concerned they will just be on
> a LAN with a /64 out of the /48 and IPv4.
>
> A cheap linux / *bsd box will do this.
>


My customer support can not instruct users to get a cheap linux box. So
what happens instead is that people will say ok, screw IPv6. Is that a
problem or not?

We designed the system believing this was not an actual problem. We
expected people to put in a router in front, and then be able to split up
their /48 from there. But reality is that it didn't work out that way.

People want to put in a switch in front of multiple routers. That is the
setup the common man understands how to configure. In part because it is
actually hard to do it any other way if you want one public IPv4 per router
and the routers are understood to be the common CPE everyone are buying at
the hardware store.

It is just sad this is not compatible with the advice we are getting on
NANOG to hand out /48. Because we can only do one /48. There is no
justification that RIPE would accept to hand out more than a /48 to a
residential end user, where the only issue is that the end user does not
know how to split up his /48.

If we did /56 (or /52) we could assign the full /48 in regards to RIPE but
have our DHCPv6 server hand it out in pieces such as a /56 at a time. This
would work for the users. But it is not so popular among some people here
on NANOG. We would be limiting the user to a /56 if he only has a single
CPE.

Perhaps the problem is that DHCPv6-PD is not intelligent enough. Yes there
is a provision such that the user CPE could give a hint of how much space
is want, but no, it doesn't work. The user CPE does not understand this
issue either and has no information that could make it the smart place to
do the decision. Plus which of the multiple CPEs would be in control?

Maybe if the CPEs would go back and ask for more address space, if what
they initially got ran out. But DHCPv6-PD does not really have a way to do
that. In any case no CPE implements any such thing.

Or maybe it is the RIPE policy that is the problem? I am not sure if the
problem is any different for the other RIRs.

Regards,

Baldur



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