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IPv6, the iPod and the Earth

We’ve been looking for an analogy for two days to explain the size of the IPv6 pool compared to IPv4, but IPv6 space is so huge none of the comparisons are immediately comprehensible. See below for Jacob’s light years attempt.

However Kim Davies reckons he has come upon an analogy that works and, if the maths is correct, we may finally have a comprehensible explanation of the comparative sizes of the two pools. Before we start using it though, it seems only sensible to get others out there to check on the calculations. So the analogy and associated maths is below. Please review it and get back.

Volume of earth: 1.0832073 × 10^12 km³
=1.0832073 × 10^21 m³
=1.0832073 × 10^27 cm³

IPv6 space: =3.4028236 × 10^38
IPv4 space: =4.2949672 × 10^9
IPv6/IPv4 space =7.9228162 × 10^28

So, if all the IPv6 space was the size of earth, then you could fit IPv4 in 73.142 cubic centimetres.

An iPod is 2.4″×4.1″×0.55″ = 5.41 cubic inches = 88.68 cubic centimetres.

So, ball park, if all the IPv4 space would fit in an iPod, then all the IPv6 space is the size of the entire Earth.


    Domain Name System
    Internationalized Domain Name ,IDN,"IDNs are domain names that include characters used in the local representation of languages that are not written with the twenty-six letters of the basic Latin alphabet ""a-z"". An IDN can contain Latin letters with diacritical marks, as required by many European languages, or may consist of characters from non-Latin scripts such as Arabic or Chinese. Many languages also use other types of digits than the European ""0-9"". The basic Latin alphabet together with the European-Arabic digits are, for the purpose of domain names, termed ""ASCII characters"" (ASCII = American Standard Code for Information Interchange). These are also included in the broader range of ""Unicode characters"" that provides the basis for IDNs. The ""hostname rule"" requires that all domain names of the type under consideration here are stored in the DNS using only the ASCII characters listed above, with the one further addition of the hyphen ""-"". The Unicode form of an IDN therefore requires special encoding before it is entered into the DNS. The following terminology is used when distinguishing between these forms: A domain name consists of a series of ""labels"" (separated by ""dots""). The ASCII form of an IDN label is termed an ""A-label"". All operations defined in the DNS protocol use A-labels exclusively. The Unicode form, which a user expects to be displayed, is termed a ""U-label"". The difference may be illustrated with the Hindi word for ""test"" — परीका — appearing here as a U-label would (in the Devanagari script). A special form of ""ASCII compatible encoding"" (abbreviated ACE) is applied to this to produce the corresponding A-label: xn--11b5bs1di. A domain name that only includes ASCII letters, digits, and hyphens is termed an ""LDH label"". Although the definitions of A-labels and LDH-labels overlap, a name consisting exclusively of LDH labels, such as"""" is not an IDN."