Re: IP4 Space

[Stan Barber <sob () academ com>]

In this case, I am talking about an IPv6<->IPv6 NAT analogue to the current IPv4<->IPv4 NAT that is widely used with 
residential Internet service delivery today.

I believe that with IPv6 having much larger pool of addresses and each residential customer getting a large chunk of 
addresses will make  IPv6<->IPv6 NAT unnecessary. I also believe that there will be IPv6 applications that require 
end-to-end communications that would be broken where NAT of that type used. Generally speaking, many users of the 
Internet today have not had the luxury to experience the end-to-end model because of the wide use of NAT. 

Given that these customers today don't routinely multihome  today, I currently believe that behavior will continue. 
Multihoming is generally more complicated and expensive than just having a single connection with a default route and 
most residential customers don't have the time, expertise or financial support to do that. So, the rate of multihoming 
will stay about the same even though the number of potential sites that could multihome could increase dramatically as 
IPv6 takes hold.

Now, there are clearly lots of specifics here that may change over time concerning what the minimum prefix length for 
IPv6 advertisements might be acceptable in the DFZ (some want that to be /32, other are ok with something longer). I 
don't know how that will change over time. I also think that that peering will continue to increase and that the prefix 
lengths that peers will exchange with each other are and will continue to be less constrained by the conventions of the 
DFZ since the whole point of peering is to be mutually beneficial to those two peers and their customers. But, that 
being said, I don't think residential customers will routinely do native IPv6 peering either. I think IP6-in-IPv4 
tunneling is and will continue to be popular and that already makes for some interesting IPv6 routing concerns. 

Hope that clarifies my comment for you. Obviously, they are my opinions, not facts. The future will determine if I was 
seeing clearly or was mistaken in how these things might unfold. However, I think a discourse about these possibilities 
is helpful in driving consensus and that's one of the valuable things about mailing lists like this.


On Mar 18, 2010, at 8:20 PM, Christopher Morrow wrote:

> On Thu, Mar 18, 2010 at 7:36 PM, Stan Barber <sob () academ com> wrote:
> > Ok. Let's get back to some basics to be sure we are talking about the same things.
> >
> >  First, do you believe that a residential customer of an ISP will get an IPv6 /56 assigned for use in their home? Do
> > you believe that residential customer will often choose to multihome using that prefix? Do you believe that on an
> > Internet that has its primary layer 3 protocol is IPv6 that a residential customer will still desire to do NAT for 
> > reaching
>
> how are nat and ipv6 and multihoming related here? (also 'that has a
> primary layer 3 protocol as ipv6' ... that's a LONG ways off)
>
> -chris
>
> > IPv6 destinations?
> >
> > I am looking forward to your response.
> >
> >
> >
> >
> > On Mar 18, 2010, at 2:25 PM, William Herrin wrote:
> >
> > > > On Mar 5, 2010, at 7:24 AM, William Herrin wrote:
> > > > > Joel made a remarkable assertion
> > > > > that non-aggregable assignments to end users, the ones still needed
> > > > > for multihoming, would go down under IPv6. I wondered about his
> > > > > reasoning. Stan then offered the surprising clarification that a
> > > > > reduction in the use of NAT would naturally result in a reduction of
> > > > > multihoming.
> > >
> > > On Thu, Mar 18, 2010 at 11:07 AM, Stan Barber <sob () academ com> wrote:
> > > > I was not trying to say there would be a reduction in multihoming. I was
> > > > trying to say that the rate of increase in non-NATed single-homing
> > > > would increase faster than multihoming. I guess I was not very clear.
> > >
> > >
> > > Hi Stan,
> > >
> > > Your logic still escapes me. Network-wise there's not a lot of
> > > difference between a single-homed  IPv4 /32 and a single-homed IPv6
> > > /56. Host-wise there may be a difference but why would you expect that
> > > to impact networks?
> > >
> > > Regards,
> > > Bill Herrin
> > >
> > >
> > >
> > > --
> > > William D. Herrin ................ herrin () dirtside com  bill () herrin us
> > > 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/>
> > > Falls Church, VA 22042-3004