Network Working Group R. Hinden
Request for Comments: 4291 Nokia
Obsoletes: 3513 S. Deering
Category: Standards Track Cisco Systems
February 2006
IP Version 6 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 (2006).
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.
This document obsoletes RFC 3513, "IP Version 6 Addressing
Architecture".
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RFC 4291 IPv6 Addressing Architecture February 2006
Table of Contents
1. Introduction ....................................................2
2. IPv6 Addressing .................................................2
2.1. Addressing Model ...........................................3
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 ..........................................6
2.5.1. Interface Identifiers ...............................7
2.5.2. The Unspecified Address .............................9
2.5.3. The Loopback Address ................................9
2.5.4. Global Unicast Addresses ............................9
2.5.5. IPv6 Addresses with Embedded IPv4 Addresses ........10
2.5.6. Link-Local IPv6 Unicast Addresses ..................11
2.5.7. Site-Local IPv6 Unicast Addresses ..................11
2.6. Anycast Addresses .........................................12
2.6.1. Required Anycast Address ...........................12
2.7. Multicast Addresses .......................................13
2.7.1. Pre-Defined Multicast Addresses ....................15
2.8. A Node's Required Addresses ...............................17
3. Security Considerations ........................................18
4. IANA Considerations ............................................18
5. Acknowledgements ...............................................18
6. References .....................................................18
6.1. Normative References ......................................18
6.2. Informative References ....................................18
Appendix A: Creating Modified EUI-64 Format Interface Identifiers .20
Appendix B: Changes from RFC 3513 .................................22
1. Introduction
This specification defines the addressing architecture of the IP
Version 6 protocol. It includes the basic formats for the various
types of IPv6 addresses (unicast, anycast, and multicast).
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.
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RFC 4291 IPv6 Addressing Architecture February 2006
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.
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