On Mon, Jan 25, 2010 at 09:10:11AM -0500, TJ wrote:
While I agree with parts of what you are saying - that using the "simple 2^128" math can be misleading, let's be clear on a few things: *) 2^61 is still very, very big. That is the number of IPv6 network segments available within 2000::/3. *) An end-user should get something between a /48 and a /56, _maybe_ as low as a /60 ... hopefully never a /64. Really. **) Let's call the /48s enterprise assignments, and the /56s home assignments ... ? **) And your /56 to /64 is NOT 1-256 IPs, it is 1-256 segments.
It is if we are to follow the "always use a /64 as a single IP" guidelines. Not that I'm encouraging this, I'm just saying this is what we're told to do with the space. I for one have this little protocol called DHCP that does IP assignments along with a bunch of other things that I need anyways, so I'm more than happy to take a single /64 for house as a single lan segment (well, never minding the fact that my house has a /48).
**) And, using the expected /48-/56, the numbers are really 256-64k subnets. ... Note: "All we've really done is buy ourselves an 8 to 16 bit improvement at every level of allocation space" *) And you don't think 8-16 bits _AT EVERY LEVEL_ is a bit deal??
I'm not saying that 8-16 bits isn't an improvement, but it's a far cry from the bazillions of numbers everyone makes IPv6 out to be. By the time you figure in the overhead of autoconfiguration, restrictive initial deployments, and the "now that the space is much bigger, we should be reallocating bigger blocks" logic at every layer of redistribution, that is what you're left with. So far all we've really done with v6 is created a flashback to the days when every end user could get a /24 just by asking, every enterprise could get a /16 just by asking, and every big network could get a /8 just by asking, just bit shifted a little bit. That's all well and good, but it isn't a bazillion. :) -- Richard A Steenbergen <ras@e-gerbil.net> http://www.e-gerbil.net/ras GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)