Matthew, On Jul 30, 2010, at 9:27 AM, Matthew Walster wrote: > On 29 July 2010 18:08, Leo Vegoda <[email protected]> wrote: >> There's a good chance that in the long run multi-subnet home networks will >> become the norm. > > 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. > /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
