> >>However, it is not necessary as worse as 2^N times. For example, it there > >>are 2 bits to separate different use types (say 4 different types), it > >>actually only separate use address spaces into four different spaces. It > >>does not limit the address space to be 1/4 of original space. > > How is that different from saying "by adding two bits of semantics in the > prefix, the network will use 4 times the address space than it would > otherwise"? > > No. This is very different. Putting the example into numbers may be more > intuitionistic. Say an ISP has 4 million subscribers, it needs 4 million /56 > (assuming every user get a /56). By separating them into 4 different types, > the address consumption is still 4 million /56 if the separation is exactly > even. However, the more > Not a great assumption... They should need 4 million or more /48s since every subscriber is at least one end site and every subscriber end site should receive a /48.
Assuming that you will get 4 million subscribers that conveniently divide into buckets of 1 million per bucket is absurd. More likely, you'll get 500,000, 750,000, 2,000,000, and 750,000, or other similarly skewed distribution. It might even be 3,500,000, 125,000, 125,000, 250,000. > address may need when the separation is not even. For example, if the biggest > user type has 2 million users, then the total address space may become 8 > million /56 – two times of original. It comes from align. The increased > semantics bit are also increasing the address space although not increasing > linearly. So, at the end, it is not totally waste. > If you get extraordinarily lucky, it's no waste. Otherwise, it's at least 50% waste and can easily reach 75% waste (4x space utilization, as Lorenzo said). For example, if you have 4,000,000 end sites and you get as little as 2,097,153 subscribers in one of the buckets, you have to go to 4x your address space to preserve the semantics. Owen > Best regards, > > Sheng > > From: Lorenzo Colitti [mailto:lore...@google.com] > Sent: Thursday, May 30, 2013 3:19 PM > To: Sheng Jiang > Cc: Tim Chown; Owen DeLong; <v6...@ietf.org>; > draft-jiang-v6ops-semantic-pre...@tools.ietf.org; ipv6@ietf.org > Subject: Re: [v6ops] Could IPv6 address be more than > locator?//draft-jiang-v6ops-semantic-prefix-03 > > > > On Thu, May 30, 2013 at 4:13 PM, Sheng Jiang <jiangsh...@huawei.com> wrote: > > Yes, there is no intension to change ARIN’s policy at all. ARIN should remain > the current policy of assign IPv6 address block. But the network providers, > who has already get address block, can choose to use the addresses with > certain semantics. And no one, including ARIN can stop this. > > > > Agreed, but even for network providers that already have blocks, this will be > an issue if they ever need another block. But I do think you should write > this in the draft. > > > > However, it is not necessary as worse as 2^N times. For example, it there are > 2 bits to separate different use types (say 4 different types), it actually > only separate use address spaces into four different spaces. It does not > limit the address space to be 1/4 of original space. > > > > How is that different from saying "by adding two bits of semantics in the > prefix, the network will use 4 times the address space than it would > otherwise"?
-------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
