Dual stack IPv6 for IPv4 depletion

Thu Jul 9 16:53:36 UTC 2015

Sure, they may be 100,000+  networks like that in non-technical households. Maybe. I doubt it, but still that would be like 0.01%. Many consumer systems have trouble with L3 hops (mDNS/Bonjour, etc...). First thing tech support will suggest it to put them on the same network. People have been taught this. My experience is that most people that even have a second network, it's their AP that sets up a Guest network, and even then, it doesn't route between the networks (that's sort of the whole idea).

If an ISP wants to give out a /48, great for them. If they want to give out only a /56, I say that's fine. What's more important to me is that they implement IPv6. Arguing about prefix size and SLAAC vs DHCP rather than just go ahead and implement things, to me is just silly. When IP was first deployed, we didn't have DHCP (bootp was still in it's infancy), no mDNS, etc...Lots of things grew up after the fact. I agree that we can't foresee what will happen in the future, but that to me just proves my point. Worrying about the ability to create complex topologies in home networks that may or may not ever be needed or wanted just seems absurd to me.

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Matthew Huff             | 1 Manhattanville Rd
Director of Operations   | Purchase, NY 10577
OTA Management LLC       | Phone: 914-460-4039
aim: matthewbhuff        | Fax:   914-694-5669

-----Original Message-----
From: Owen DeLong [mailto:owen at delong.com] 
Sent: Thursday, July 9, 2015 12:36 PM
To: Matthew Huff
Cc: Marco Teixeira; Harald Koch; NANOG list
Subject: Re: Dual stack IPv6 for IPv4 depletion

> On Jul 9, 2015, at 08:42 , Matthew Huff <mhuff at ox.com> wrote:
> 
> What am I missing? Is it just the splitting on the sextet boundary that is an issue, or do people think people really need 64k subnets per household?
> 

It's the need for a large enough bitfield to do more flexible things with auto-delegation in a dynamic self-organizing topology.

8 is 2x2x2 and there's really no other way you can break it down. (2x4, 4x2, 2x2x2 is it.)

16 is 2x2x2x2 and allows many more possible topologies (4x4, 2x4x2, 2x2x4, 2x8, 8x2, etc.)

> With /56 you are giving each residential customer:
> 
> 256 subnets x 18,446,744,073,709,551,616 hosts per subnet.

The host count is irrelevant to the discussion.

> 
> I would expect at least 95.0% of residential customers are using 1 subnet, and 99.9% are using less than 4. I can understand people complaining when some ISPs were deciding to only give out a /64, but even with new ideas, new protocols and new applications, do people really think residential customers will need more than 256 subnets? When such a magical new system is developed, and people start to want it, can't ISPs start new /48 delegations? Since DHCP-PD and their infrastructure will already be setup for /56, it may not be easy, but it shouldn't be that difficult.

I would expect that basing decisions about limits on tomorrows network on the inadequacy of today's solutions is unlikely to yield good results.

Further, I'm not so sure you are right in your belief. I suspect that there are many more networks in most households that you are not counting. Sure, those networks are currently usually disjoint, but do you really think it will always be that way in the future?

Every phone is a router. Ever tablet is a router. Cars are becoming routers and in some cases, collections of routers. Set top boxes are becoming routers.

Utility meters are becoming routers.

Laptops and desktops are capable of being routers.

> I know the saying "build it and they will come....", but seriously....
> 
> I'd rather ISPs stop discussing deploying IPv6, and start doing it.

I'm all for that, but do you have a valid reason not to give out /48s per end site? Just because /56 might be enough doesn't cut it. I'm asking if you can point to any tangible benefit obtained from handing out /56s instead? Is there any problem solved, labor saved, or any other benefit whatsoever to giving out /56s instead of /48s?

If not, then let's hand out /48s until we discover one.

Owen