ISP customer assignments

Brian Johnson bjohnson at
Tue Oct 6 15:09:45 UTC 2009

Rick et al,

I work at an ISP, and I know staff at several other ISPs, we are all
trying to do this right. If a /56 makes sense and is supported by the
IPv6 technology and we won't have issues supplying these to customers
(technically speaking), then we will most likely do this or something
similar. The issue is more of a nuanced issue.

There seems to be a variance between "It's OK to just give out a /64" to
"You better be thinking about giving out a /48". I can live in those
boundaries and am most likely fine with either. I'm leaning toward a /56
for regular subscribers and a /48 only for business or large scale
customers, and undecided on dial-up. How does this sound?

This wasn't suppose to digress to this level of vitriol.

- Brian

> -----Original Message-----
> From: Ricky Beam [mailto:jfbeam at]
> Sent: Monday, October 05, 2009 10:23 PM
> To: Joe Greco; Robert.E.VanOrmer at
> Cc: nanog at
> Subject: Re: ISP customer assignments
> On Mon, 05 Oct 2009 20:14:01 -0400, Joe Greco <jgreco at>
> wrote:
> > Generally speaking, we shouldn't *want* end users to be provided
> a
> > single /64.  The number of addresses is not the point.  The idea of
> > getting rid of the horribleness that is CIDR is the point.
> You underestimate the power of the marketing department and the bean
> counters.  I assure you, residential ISPs are looking for schemes to
> give
> out as little address space as possible.
> > The current revision of IPv6 introduces a way to nail down the
> boundary
> > between network and host.  This is fantastic, from an implementation
> > point of view.  It simplifies the design of silicon for forwarding
> > engines, etc.
> And it's 150% Wrong Thinking(tm).  IPv6 is classless - PERIOD.  The
> instant some idiot wires /64 into silicon, we're right back to not
> being
> able to use x.x.x.0 and x.x.x.255.  Addresses are 128-bits; you cannot
> make any assumptions about what people may or may not be doing with
> those
> bits.  If I don't use SLAAC, then I'm not bound by it's lame rules.
> > You don't do that.  Or at least, you shouldn't do that.  :-)  We
> a
> > fairly reliable DNS system these days...
> And where did DNS get the name/number assignments?  In my case, it's
> either been typed in by ME or automatically updated by DHCP.
> --Ricky

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