Unicast IPv6 Addresses and IPv6 Subnetting
IPv6 defines two major types of unicast IPv6 addresses. Global unicast addresses work like public IPv4 addresses in that the enterprise obtains a unique prefix with all addresses inside the enterprise beginning with that prefix. With all companies using unique prefixes, all addresses in the IPv6 Internet should be unique.
Unique local unicast addresses work more like private addresses. A company can randomly create a prefix and assign addresses that begin with that prefix. Unique local addresses let companies avoid having to register a prefix while still having a good statistical chance of not using the same address range as other companies.
To create subnets with global unicast addresses, a company ...