[128303] in North American Network Operators' Group
Re: Addressing plan exercise for our IPv6 course
daemon@ATHENA.MIT.EDU (David Conrad)
Fri Jul 30 04:20:33 2010
From: David Conrad <drc@virtualized.org>
In-Reply-To: <AANLkTimVj8rnsGr0_2kr-by=4fbz5DwUB-ameiR+woQy@mail.gmail.com>
Date: Fri, 30 Jul 2010 10:20:19 +0200
To: Matthew Walster <matthew@walster.org>
Cc: nanog list <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
Matthew,
On Jul 30, 2010, at 9:27 AM, Matthew Walster wrote:
> On 29 July 2010 18:08, Leo Vegoda <leo.vegoda@icann.org> wrote:
>> There's a good chance that in the long run multi-subnet home networks =
will become the norm.
>=20
> Why would a home user need multiple subnets?
Even today, people are deploying multiple subnets in their homes. For =
example, Apple's Airport allows you to trivially set up a "guest" =
network that uses a different prefix (192.168.0.0/24) and different SSID =
than your "normal" network (10.0.1.0/24).
> Are they really likely to have CPE capable of routing between subnets =
at 21st Century LAN speeds?
Sure. Given time and Moore's law, I figure that's pretty much =
guaranteed.
> Isn't that needlessly complicating the home environment?
It's really a question of time horizons.
If you buy into a future world of sensornets and massive home =
automation, rooms in houses would have tens or hundreds of devices, all =
individually addressable. And that's ignoring devices hung off your body =
attached via a personal area network. In such an environment, I can =
easily imagine multiple subnets.
Of course, not everyone buys into these ideas (and they're certainly not =
going to happen tomorrow), however I believe one of the rationales =
behind /48s is "why architect in impediments if you don't have to?".
> It just seems *wasteful* to me.
It is (mindboggling so), in the sense of address utilization. However, =
there are a lot of /48s in IPv6 (if you multiply the current IPv4 =
address consumption rate by 1000, the 1/8th of the IPv6 address space =
currently used for global unicast allocations would last about 120 =
years), so people are suggesting we optimize for flexibility.
As various people have noted, innovation is greatly facilitated when you =
have plentiful resources (mechanical power: industrial revolution, cpu =
power: GUIs, bandwidth: on-demand entertainment, etc). I gather the =
theory is that if you remove the need to be efficient with addresses, =
you'll see new innovations in the use of the network.=20
> /32 is a
> lot of space, if most customers are only going to have a few machines
> on one subnet, why not just give them a /64 and have an easy way to
> just click on a button on your customer portal or similar to assign a
> /48 and get it routed to them.
Unless you allocate the /64 out of the /48 you'd assign to them (in =
which case, why not simply assign the /48), it would force the customer =
to renumber. Perhaps not that big a deal, but it seems like work for =
little benefit.
Regards,
-drc
