RFC 2526 (rfc2526) - Page 1 of 7
Reserved IPv6 Subnet Anycast Addresses
Alternative Format: Original Text Document
Network Working Group D. Johnson
Request for Comments: 2526 Carnegie Mellon University
Category: Standards Track S. Deering
Cisco Systems, Inc.
March 1999
Reserved IPv6 Subnet Anycast Addresses
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 (1999). All Rights Reserved.
Abstract
The IP Version 6 addressing architecture defines an "anycast" address
as an IPv6 address that is assigned to one or more network interfaces
(typically belonging to different nodes), with the property that a
packet sent to an anycast address is routed to the "nearest"
interface having that address, according to the routing protocols'
measure of distance. This document defines a set of reserved anycast
addresses within each subnet prefix, and lists the initial allocation
of these reserved subnet anycast addresses.
1. Introduction
IP Version 6 (IPv6) defines a new type of address, known as an
"anycast" address, that allows a packet to be routed to one of a
number of different nodes all responding to the same address [2, 3].
The anycast address may be assigned to one or more network interfaces
(typically on different nodes), with the network delivering each
packet addressed to this address to the "nearest" interface based on
the notion of "distance" determined by the routing protocols in use.
The uses of anycast addresses are still evolving, but such addresses
offer the potential for a number of important services [5, 6]. For
example, an anycast address may be used to allow nodes to access one
of a collection of servers providing a well-known service, without
manual configuration in each node of the list of servers; or an
Johnson & Deering Standards Track