Ha: [address-policy-wg] RE: an arithmetic lesson
David Conrad drc at virtualized.org
Thu Dec 3 19:33:17 CET 2009
Hmm.. It is (or rather, should be) obvious that there are exactly the same number of /24s or /8s or /<anything up to 32>s in IPv4 as there are in IPv6. It is (or should be) equally obvious to state that the amount addressed by an IPv6 /<anything up to a 32> is VASTLY larger than in IPv4. Except when you blow away the lower 96 bits in an IPv6 address for protocol reasons. When I mentioned class As, I was speaking figuratively. The point that I was attempting to make was that early adopters of IPv4 were able to obtain "class As" with minimal justification. As the IPv4 free pool depletes, it becomes increasingly hard to obtain (the equivalent of) "class As". I suspect most of us now look at the "class A" allocations as historical mistakes that we'd like to remedy, but don't because it is undoubtedly too much trouble (and please, can we not rathole on reclamation of legacy address space yet again?). Allocating IPv6 /24 now when we have "plenty" of IPv6 address space because it makes a particular protocol proposal more convenient is, in my view, simply repeating history. It is _the equivalent of_ allocating "class As". Regards, -drc On Dec 3, 2009, at 7:03 AM, Remco van Mook wrote: > To upset some more sentiments; compare v4 /24s with the available v4 unicast; do the same with v6 /24s and current v6 unicast space. Rough arithmetic shows then that in that line of reasoning, a v6 /24 is more comparable to a v4 /20. > > Remco > > ----- Original Message ----- > From: address-policy-wg-admin at ripe.net <address-policy-wg-admin at ripe.net> > To: Dmitriy V Menzulskiy <DMenzulskiy at beeline.ru> > Cc: michael.dillon at bt.com <michael.dillon at bt.com>; address-policy-wg at ripe.net <address-policy-wg at ripe.net> > Sent: Thu Dec 03 14:20:22 2009 > Subject: Re: Ha: [address-policy-wg] RE: an arithmetic lesson > > > On Dec 3, 2009, at 7:55 AM, Dmitriy V Menzulskiy wrote: > > > > > > > > > > On 3 Dec 2009, at 10:00, <michael.dillon at bt.com> wrote: > > > > > > > > > an IPv6 /24 and an IPv4 /24 use up the same percentage of the > > total > > > > > address space. > > > > > > > > How do you work that out? Please enlighten me. 2^24/2^128 x > > > > 100 is many orders of magnitude smaller than 2^24/2^32 x 100: > > > > gromit% bc > > > > scale=50 > > > > 2^24/2^128*100 > > > > .00000000000000000000000000000493038065763132378300 > > > > 2^24/2^32*100 > > > > .39062500000000000000000000000000000000000000000000 > > > > > > > > There are of course the same number of IPv4 and IPv6 /24s. > > > > > > Percentage is calculated by dividing the number of things > > > under consideration by the total number of things. When > > > I used the word "an", I meant one thing. > > > > > > Assuming that the number of IPv4 and IPv6 /24s is 10 > > > > > > 1/10 = 1/10 > > > > > > Assuming that the number of IPv4 and IPv6 /24s is 8192 > > > > > > 1/8192 = 1/8192 > > > > > > Assuming that the number of IPv4 and IPv6 /24s is 2882873787 > > > > > > 1/2882873787 = 1/2882873787 > > > > > > Do you see a pattern forming? > > > > > > --Michael Dillon > > > > > > > As I understand: > > > > IPv4 /24 is (Total IPv4)/(2^24) > > IPv6 /24 is (Total IPv6)/(2^24) > > > > Or not ? > > > Not. > > The ratio you want, using your formalism, is > > (2^(size of address space - 24)) / (Total IPvX) > > which is 2^(N - 24) / 2^N = 1 / 2^24 > > (where N is the number of bits in the address space). > > Regards > Marshall > > > > > > WBR, > > > > Dmitry Menzulskiy, DM3740-RIPE > > > > > > > This email is from Equinix Europe Limited or one of its associated/subsidiary companies. This email, and any files transmitted with it, contains information which is confidential, may be legally privileged and is solely for the use of the intended recipient. If you have received this email in error, please notify the sender and delete this email immediately. Equinix Europe Limited. Registered Office: Quadrant House, Floor 6, 17 Thomas More Street, Thomas More Square, London E1W 1YW. Registered in England and Wales No. 6293383.