Network Information Center (APNIC) or the American
Registry for Internet Numbers (ARIN). The regional
registries assign /32 blocks of IPv6 addresses to the
Internet service providers (ISPs) that operate in their
geographic areas. The ISPs, in turn, assign /48 IPv6
subnets to their customers, which can subnet further and
create their own subnets, usually down to a /64, giving
them up to 65,536 IPv6 subnets that they can assign to
their sites.
The interface ID portion of an IPv6 address is usually
based on the MAC address of the device, following the
EUI-64 specification. This specification creates the 64
bits needed for the interface ID portion of the address by
splitting the 48-bit MAC address right down the middle
and inserting the 16-bit 0xFFFE between the OUI and
the vendor-assigned bits.
The hierarchical distribution of IPv6 addresses allows for
better aggregation of routes, which leads to smaller
Internet routing tables and faster routing.
There are several different types of IPv6 addresses:
Global
Link-local
Multicast
Loopback
UnspecifiedGlobal IPv6 addresses are the equivalent of public
unicast IPv4 addresses. Global IPv6 addresses are
assigned in a controlled fashion so that they can be easily
aggregated at all levels, registry, ISPs, and customers.
Currently IANA is assigning IPv6 addresses that start
with the binary value 001 (2000::/3). This represents
one-eighth of the total IPv6 address space. A global