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 TomS_Git-r-donePremium,MVM
join:2002-07-19
Ireland
kudos:1 | reply to patcat88
Re: Citizen identification said by patcat88:But we already gave half the address space away to MAC addresses. No we didnt. 64 bits is not half of the IPv6 address space. It may be half of the number of bits, but with each bit you add you have to double the amount of combinations. To give away half of the address space you need to work on a 127 bit boundary.
i.e. 127 bits with the 128th (left hand most bit) being 0, and 127 bits with the 128th bit being 1. Those are the two halves of the address apce. 
64 bits gives you 18,446,744,073,709,551,616 (18 billion billion) possible combinations.
128 bits gives you 340,282,366,920,938,463,463,374,607,431,768,211,456 (340 billion billion billion billion) possible combinations.
The number of times that the former goes into the latter is 18,446,744,073,709,551,616.
So we have given away 1/18,446,744,073,709,551,616 of all possible IPv6 address space.
But it is not to "MAC addresses" as such... | |
patcat88
join:2002-04-05
Jamaica, NY
kudos:1
1 edit | said by TomS_:i.e. 127 bits with the 128th (left hand most bit) being 0, and 127 bits with the 128th bit being 1. Those are the two halves of the address apce. Your right. I should have said half the bits of capacity.
But with each residential subscriber we waste 18,446,744,073,709,551,615 to 18,446,744,073,709,551,600 IP addresses or 4,294,967,296 IPv4s worth of addresses  | | |
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