I am not deny there will be waste. My point is only it is not as much waste as 1/2^n. However, giving /48 to every subscriber, for me, is much bigger waste and luxury. You are assuming every subscriber has as many as than 2^16 subnets? Currently, there may not be more than 16 devices in an average subscriber’s own network. On other side, why subscriber may want more than one subnets? One reasonable reason is to organize different traffics or applications in different subnets. So, these kind of traffic differentiation is also meaningful semantic for providers. If the provider has differentiate these traffics in higher bits of prefixes using semantic prefix, the smaller prefix subscriber are needed. Maybe /58, or /60 is enough for subscribers, if the providers has well separate the traffic for them by assign multiple prefix regarding to different semantic?
Cheers, Sheng From: Owen DeLong [mailto:[email protected]] Sent: Friday, May 31, 2013 12:08 AM To: Sheng Jiang Cc: Lorenzo Colitti; Tim Chown; <[email protected]>; [email protected]; [email protected] Subject: Re: [v6ops] Could IPv6 address be more than locator?//draft-jiang-v6ops-semantic-prefix-03 >>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:[email protected]] Sent: Thursday, May 30, 2013 3:19 PM To: Sheng Jiang Cc: Tim Chown; Owen DeLong; <[email protected]<mailto:[email protected]>>; [email protected]<mailto:[email protected]>; [email protected]<mailto:[email protected]> 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 <[email protected]<mailto:[email protected]>> 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"?
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