# IANA ipv6 globla unicast addres

I read the IANA address space (http://www.iana.org/assignments/ipv6-address-space/ipv6-address-space.xhtml) and it says that the  assignments are currently limited to the IPv6 unicast address range of 2000::/3. But then on http://www.iana.org/assignments/ipv6-unicast-address-assignments/ipv6-unicast-address-assignments.xhtml, I don't see any 2000 IPv6 addresses. Can somebody educate me on this? Thanks
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Professional Troublemaker^h^h^h^h^hshooterCommented:
Looking at that 2000::/3... written in binary as: 0010 0000 0000 0000, and that /3 says we're only working with the first three bits.  (Each character in the IPv6 address is a hexadecimal character, and thus is 4-bits long.)  Therefore any address that starts with binary 001 will be in this assignment range.  That'll range from 2000:: to 3FFF::  The 2001, 2002, 2003, 2600 etc are all in that range.
2000 = 0010 0000 0000 0000
3FFF = 0011 1111 1111 1111

If we wanted to write 2000:: so that all the zeros there were significant a well... we'd write it at 2000::/16.

Does that make sense?  Or should I try other examples?
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AccountingAuthor Commented:
Yes, It was very clear. Thank you.

Now how many /48 can I get from that /3?? What is the formula to get there?

Also, I don't see any 2000 addresses from http://www.iana.org/assignments/ipv6-unicast-address-assignments/ipv6-unicast-address-assignments.xhtml. Do you know if there is any document from IANA that says that 2000 is reserved for such and such?
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Professional Troublemaker^h^h^h^h^hshooterCommented:
How many /48 networks is there in a /3 assignment?  It would be 2^(48-3) = 2^45 or about 35 quadrillion (or 35,184 trillion or 35 million-billion... aren't big numbers fun?)

I don't know if 2000::/16 is reserved for some reason.  Looking around, I've seen people in forums mention that they are set assign for regional registries, but that doesn't make any sense because ALL the assignments in the table you have from the IANA are to regional registries already.  Based on the notes at the head of the table, I'd say 2000::/16 is unassigned, "reserved by IANA for future allocation"
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Commented:
http://www.sabi.co.uk/Notes/swIPv6Prefixes.html

from 2000:0000::/16 to 2000:ffff::/16 is reserved.......
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