IPv6 Scoped Address Architecture
RFC 4007

Network Working Group                                         S. Deering
Request for Comments: 4007                                 Cisco Systems
Category: Standards Track                                    B. Haberman
                                                      Johns Hopkins Univ
                                                               T. Jinmei
                                                                 Toshiba
                                                             E. Nordmark
                                                        Sun Microsystems
                                                                 B. Zill
                                                               Microsoft
                                                              March 2005

                    IPv6 Scoped Address Architecture

Status of This Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2005).

Abstract

   This document specifies the architectural characteristics, expected
   behavior, textual representation, and usage of IPv6 addresses of
   different scopes.  According to a decision in the IPv6 working group,
   this document intentionally avoids the syntax and usage of unicast
   site-local addresses.

Deering, et al.             Standards Track                     [Page 1]
RFC 4007            IPv6 Scoped Address Architecture          March 2005

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Definitions  . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Basic Terminology  . . . . . . . . . . . . . . . . . . . . .   3
   4.  Address Scope  . . . . . . . . . . . . . . . . . . . . . . .   3
   5.  Scope Zones  . . . . . . . . . . . . . . . . . . . . . . . .   4
   6.  Zone Indices . . . . . . . . . . . . . . . . . . . . . . . .   6
   7.  Sending Packets  . . . . . . . . . . . . . . . . . . . . . .  11
   8.  Receiving Packets  . . . . . . . . . . . . . . . . . . . . .  11
   9.  Forwarding . . . . . . . . . . . . . . . . . . . . . . . . .  11
   10. Routing  . . . . . . . . . . . . . . . . . . . . . . . . . .  13
   11. Textual Representation . . . . . . . . . . . . . . . . . . .  15
       11.1.  Non-Global Addresses  . . . . . . . . . . . . . . . .  15
       11.2.  The <zone_id> Part. . . . . . . . . . . . . . . . . .  15
       11.3.  Examples. . . . . . . . . . . . . . . . . . . . . . .  17
       11.4.  Usage Examples. . . . . . . . . . . . . . . . . . . .  17
       11.5.  Related API . . . . . . . . . . . . . . . . . . . . .  18
       11.6.  Omitting Zone Indices . . . . . . . . . . . . . . . .  18
       11.7.  Combinations of Delimiter Characters. . . . . . . . .  18
   12. Security Considerations  . . . . . . . . . . . . . . . . . .  19
   13. Contributors . . . . . . . . . . . . . . . . . . . . . . . .  20
   14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . .  20
   15. References . . . . . . . . . . . . . . . . . . . . . . . . .  20
       15.1. Normative References . . . . . . . . . . . . . . . . .  20
       15.2. Informative References . . . . . . . . . . . . . . . .  21
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . .  22
   Full Copyright Statement . . . . . . . . . . . . . . . . . . . .  24

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

Deering, et al.             Standards Track                     [Page 2]
RFC 4007            IPv6 Scoped Address Architecture          March 2005

   local addresses will be documented elsewhere in the future.  Thus,