Editing IPv6 (section)

== Address Space ==

[http://www.denis.lemire.name/media/IPv6%20Address%20Space.pdf http://www.denis.lemire.name/images/wiki/ipv6-address-space.png]

=== Allocation and Assignments ===

Minimum direct allocation is currently /32.

ISP assignments are as follows:

* /64 when it is known that one and only one subnet is needed.
* /56 for small sites, those expected to need only a few subnets over the next 5 years.
* /48 for larger sites



=== Addresses Space Size ===

* 340,282,366,920,938,463,463,374,607,431,768,211,456 unique IPs
* 42,535,295,865,117,307,932,921,825,928,971,026,432 IPs in '''2000::/3''' (1/8<sup>th</sup> of total address space)
* 1,208,925,819,614,629,174,706,176 IPs in a '''/48'''
* 536,870,912 '''/32''' prefixes within '''2000::/3'''
* 65,536 '''/48''' prefixes with a '''/32'''
* 65,536 '''/64''' subnets within a '''/48'''
* 35,184,372,088,832 '''/48''' prefixes within '''2000::/3'''
* 8,192 IPv6 '''/48''' prefixes for every IPv4 address in '''2000::/3''' alone.
* 18,446,744,073,709,551,616 IPs within a '''/64''' subnet

=== Special Prefixes ===

* ::/8
** ::/128 - Unspecified
** ::1/128 - loopback (IPv4 127/8 equivalent)
** ::ffff:0:0/96 - IPv4 mapped addresses
* 2000::/3 - IANA Global Unicast
** 2001::/32 - Teredo (RFC-4380)
** 2001:10::/28 - Orchid (RFC-4843)
** 2002::/16 - 6to4
* FC00::/7 - unique local addresses
** FC00::/8 is to be managed by a so-called "ULA-Central" for assigned /48s. As of 9-2007, this body has yet to be formed.
** FD00::/8 is allocated by appending a randomly-generated 40-bit string, to derive a valid /48. RFC4193 offers a suggestion on how to do the random generation, to try to guarantee a minimum-quality result if the user does not have access to a good source of random numbers.
* FE80::/10 - link-local addresses (169.254/16 equivalent)
* FECO::/10 - site-local (deprecated)
* FF00::/8 - multicast

The remaining prefixes are all reserved for future Unicast allocations.

=== Multicast Addresses ===

Multicast addresses exist within the '''FF00::/8'' prefix.

* '''FF02::1''' - all v6 hosts on local subnet (IPv4 equivalent 224.0.0.1)
* '''FF02::2''' - all v6 routers on local subnet (IPv4 equivalent 224.0.0.2)