IPv6 Global Unicast Address Format

It is anticipated that unicast addressing will be used for the vast majority of Internet traffic under IPv6, as is the case for IPv4. It is for this reason that the largest of the assigned blocks of the IPv6 address space is dedicated to unicast addressing. A full one-eighth slice of the enormous IPv6 address "pie" is assigned to unicast addresses, which are indicated by a 001 in the first three bits of the address. The question is: How do we use the remaining 125 bits in the spacious IP addresses?

Rationale for a Structured Unicast Address Block

When IPv4 was first created, the Internet was rather small, and the model for allocating address blocks was based on a central coordinator: the Internet Assigned Numbers ...

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