rfc3513.txt

bind 9.3结合mysql数据库

Network Working Group                                          R. Hinden
Request for Comments: 3513                                         Nokia
Obsoletes: 2373                                               S. Deering
Category: Standards Track                                  Cisco Systems
                                                              April 2003


       Internet Protocol Version 6 (IPv6) Addressing 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 (2003).  All Rights Reserved.

Abstract

   This specification defines the addressing architecture of the IP
   Version 6 (IPv6) protocol.  The document includes the IPv6 addressing
   model, text representations of IPv6 addresses, definition of IPv6
   unicast addresses, anycast addresses, and multicast addresses, and an
   IPv6 node's required addresses.























Hinden & Deering            Standards Track                     [Page 1]

RFC 3513              IPv6 Addressing Architecture            April 2003


Table of Contents

   1. Introduction.................................................3
   2. IPv6 Addressing..............................................3
      2.1 Addressing Model.........................................4
      2.2 Text Representation of Addresses.........................4
      2.3 Text Representation of Address Prefixes..................5
      2.4 Address Type Identification..............................6
      2.5 Unicast Addresses........................................7
          2.5.1 Interface Identifiers..............................8
          2.5.2 The Unspecified Address............................9
          2.5.3 The Loopback Address...............................9
          2.5.4 Global Unicast Addresses..........................10
          2.5.5 IPv6 Addresses with Embedded IPv4 Addresses.......10
          2.5.6 Local-use IPv6 Unicast Addresses..................11
      2.6 Anycast Addresses.......................................12
          2.6.1 Required Anycast Address..........................13
      2.7 Multicast Addresses.....................................13
          2.7.1 Pre-Defined Multicast Addresses...................15
      2.8 A Node's Required Addresses.............................17
   3. Security Considerations.....................................17
   4. IANA Considerations.........................................18
   5. References..................................................19
      5.1 Normative References....................................19
      5.2 Informative References..................................19
   APPENDIX A: Creating Modified EUI-64 format Interface IDs......21
   APPENDIX B: Changes from RFC-2373..............................24
   Authors' Addresses.............................................25
   Full Copyright Statement.......................................26






















Hinden & Deering            Standards Track                     [Page 2]

RFC 3513              IPv6 Addressing Architecture            April 2003


1.  Introduction

   This specification defines the addressing architecture of the IP
   Version 6 (IPv6) protocol.  It includes the basic formats for the
   various types of IPv6 addresses (unicast, anycast, and multicast).

   The authors would like to acknowledge the contributions of Paul
   Francis, Scott Bradner, Jim Bound, Brian Carpenter, Matt Crawford,
   Deborah Estrin, Roger Fajman, Bob Fink, Peter Ford, Bob Gilligan,
   Dimitry Haskin, Tom Harsch, Christian Huitema, Tony Li, Greg
   Minshall, Thomas Narten, Erik Nordmark, Yakov Rekhter, Bill Simpson,
   Sue Thomson, Markku Savela, and Larry Masinter.

2. IPv6 Addressing

   IPv6 addresses are 128-bit identifiers for interfaces and sets of
   interfaces (where "interface" is as defined in section 2 of [IPV6]).
   There are three types of addresses:

   Unicast:   An identifier for a single interface.  A packet sent to a
              unicast address is delivered to the interface identified
              by that address.

   Anycast:   An identifier for a set of interfaces (typically belonging
              to different nodes).  A packet sent to an anycast address
              is delivered to one of the interfaces identified by that
              address (the "nearest" one, according to the routing
              protocols' measure of distance).

   Multicast: An identifier for a set of interfaces (typically belonging
              to different nodes).  A packet sent to a multicast address
              is delivered to all interfaces identified by that address.

   There are no broadcast addresses in IPv6, their function being
   superseded by multicast addresses.

   In this document, fields in addresses are given a specific name, for
   example "subnet".  When this name is used with the term "ID" for
   identifier after the name (e.g., "subnet ID"), it refers to the
   contents of the named field.  When it is used with the term "prefix"
   (e.g., "subnet prefix") it refers to all of the address from the left
   up to and including this field.

   In IPv6, all zeros and all ones are legal values for any field,
   unless specifically excluded.  Specifically, prefixes may contain, or
   end with, zero-valued fields.





Hinden & Deering            Standards Track                     [Page 3]

RFC 3513              IPv6 Addressing Architecture            April 2003


2.1 Addressing Model

   IPv6 addresses of all types are assigned to interfaces, not nodes.
   An IPv6 unicast address refers to a single interface.  Since each
   interface belongs to a single node, any of that node's interfaces'
   unicast addresses may be used as an identifier for the node.

   All interfaces are required to have at least one link-local unicast
   address (see section 2.8 for additional required addresses).  A
   single interface may also have multiple IPv6 addresses of any type
   (unicast, anycast, and multicast) or scope.  Unicast addresses with
   scope greater than link-scope are not needed for interfaces that are
   not used as the origin or destination of any IPv6 packets to or from
   non-neighbors.  This is sometimes convenient for point-to-point
   interfaces.  There is one exception to this addressing model:

      A unicast address or a set of unicast addresses may be assigned to
      multiple physical interfaces if the implementation treats the
      multiple physical interfaces as one interface when presenting it
      to the internet layer.  This is useful for load-sharing over
      multiple physical interfaces.

   Currently IPv6 continues the IPv4 model that a subnet prefix is
   associated with one link.  Multiple subnet prefixes may be assigned
   to the same link.

2.2 Text Representation of Addresses

   There are three conventional forms for representing IPv6 addresses as
   text strings:

   1. The preferred form is x:x:x:x:x:x:x:x, where the 'x's are the
      hexadecimal values of the eight 16-bit pieces of the address.

      Examples:

         FEDC:BA98:7654:3210:FEDC:BA98:7654:3210

         1080:0:0:0:8:800:200C:417A

      Note that it is not necessary to write the leading zeros in an
      individual field, but there must be at least one numeral in every
      field (except for the case described in 2.).

   2. Due to some methods of allocating certain styles of IPv6
      addresses, it will be common for addresses to contain long strings
      of zero bits.  In order to make writing addresses containing zero
      bits easier a special syntax is available to compress the zeros.



Hinden & Deering            Standards Track                     [Page 4]

RFC 3513              IPv6 Addressing Architecture            April 2003


      The use of "::" indicates one or more groups of 16 bits of zeros.
      The "::" can only appear once in an address.  The "::" can also be
      used to compress leading or trailing zeros in an address.

      For example, the following addresses:

         1080:0:0:0:8:800:200C:417A  a unicast address
         FF01:0:0:0:0:0:0:101        a multicast address
         0:0:0:0:0:0:0:1             the loopback address
         0:0:0:0:0:0:0:0             the unspecified addresses

      may be represented as:

         1080::8:800:200C:417A       a unicast address
         FF01::101                   a multicast address
         ::1                         the loopback address
         ::                          the unspecified addresses

   3. An alternative form that is sometimes more convenient when dealing
      with a mixed environment of IPv4 and IPv6 nodes is
      x:x:x:x:x:x:d.d.d.d, where the 'x's are the hexadecimal values of
      the six high-order 16-bit pieces of the address, and the 'd's are
      the decimal values of the four low-order 8-bit pieces of the
      address (standard IPv4 representation).  Examples:

         0:0:0:0:0:0:13.1.68.3

         0:0:0:0:0:FFFF:129.144.52.38

      or in compressed form:

         ::13.1.68.3

         ::FFFF:129.144.52.38

2.3 Text Representation of Address Prefixes

   The text representation of IPv6 address prefixes is similar to the
   way IPv4 addresses prefixes are written in CIDR notation [CIDR].  An
   IPv6 address prefix is represented by the notation:

      ipv6-address/prefix-length

   where

      ipv6-address    is an IPv6 address in any of the notations listed
                      in section 2.2.




Hinden & Deering            Standards Track                     [Page 5]

RFC 3513              IPv6 Addressing Architecture            April 2003


      prefix-length   is a decimal value specifying how many of the
                      leftmost contiguous bits of the address comprise
                      the prefix.

   For example, the following are legal representations of the 60-bit
   prefix 12AB00000000CD3 (hexadecimal):

      12AB:0000:0000:CD30:0000:0000:0000:0000/60
      12AB::CD30:0:0:0:0/60
      12AB:0:0:CD30::/60

   The following are NOT legal representations of the above prefix:

      12AB:0:0:CD3/60   may drop leading zeros, but not trailing zeros,
                        within any 16-bit chunk of the address

      12AB::CD30/60     address to left of "/" expands to
                        12AB:0000:0000:0000:0000:000:0000:CD30

      12AB::CD3/60      address to left of "/" expands to
                        12AB:0000:0000:0000:0000:000:0000:0CD3

   When writing both a node address and a prefix of that node address
   (e.g., the node's subnet prefix), the two can combined as follows:

      the node address      12AB:0:0:CD30:123:4567:89AB:CDEF
      and its subnet number 12AB:0:0:CD30::/60

      can be abbreviated as 12AB:0:0:CD30:123:4567:89AB:CDEF/60

2.4 Address Type Identification

   The type of an IPv6 address is identified by the high-order bits of
   the address, as follows:

   Address type         Binary prefix        IPv6 notation   Section
   ------------         -------------        -------------   -------
   Unspecified          00...0  (128 bits)   ::/128          2.5.2
   Loopback             00...1  (128 bits)   ::1/128         2.5.3
   Multicast            11111111             FF00::/8        2.7
   Link-local unicast   1111111010           FE80::/10       2.5.6
   Site-local unicast   1111111011           FEC0::/10       2.5.6
   Global unicast       (everything else)

   Anycast addresses are taken from the unicast address spaces (of any
   scope) and are not syntactically distinguishable from unicast
   addresses.




Hinden & Deering            Standards Track                     [Page 6]

RFC 3513              IPv6 Addressing Architecture            April 2003


   The general format of global unicast addresses is described in
   section 2.5.4.  Some special-purpose subtypes of global unicast
   addresses which contain embedded IPv4 addresses (for the purposes of
   IPv4-IPv6 interoperation) are described in section 2.5.5.

   Future specifications may redefine one or more sub-ranges of the
   global unicast space for other purposes, but unless and until that
   happens, implementations must treat all addresses that do not start
   with any of the above-listed prefixes as global unicast addresses.

2.5 Unicast Addresses

   IPv6 unicast addresses are aggregable with prefixes of arbitrary
   bit-length similar to IPv4 addresses under Classless Interdomain
   Routing.

   There are several types of unicast addresses in IPv6, in particular
   global unicast, site-local unicast, and link-local unicast.  There
   are also some special-purpose subtypes of global unicast, such as
   IPv6 addresses with embedded IPv4 addresses or encoded NSAP
   addresses.  Additional address types or subtypes can be defined in
   the future.