1. Introduction

1. Introduction

Internet Protocol version 6 includes support for addresses of different "scope"; that is, both global and non-global (e.g., link-local) addresses. Although non-global addressing has been introduced operationally in the IPv4 Internet, both in the use of private address space ("net 10", etc.) and with administratively scoped multicast addresses, the design of IPv6 formally incorporates the notion of address scope into its base architecture. This document specifies the architectural characteristics, expected behavior, textual representation, and usage of IPv6 addresses of different scopes.

Though the current address architecture specification [1] defines unicast site-local addresses, the IPv6 working group decided to deprecate the syntax and the usage [5] and is now investigating other forms of local IPv6 addressing. The usage of any new forms of local addresses will be documented elsewhere in the future. Thus, this document intentionally focuses on link-local and multicast scopes only.