Network Working Group                             S. Deering, Xerox PARC
Request for Comments: 1883                  R.  Hinden, Ipsilon Networks
Category: Standards Track                                  December 1995




                  Internet Protocol, Version 6 (IPv6)
                             Specification





Status of this Memo(RFC1661に同じ)

Abstract


   This document specifies version 6 of the Internet Protocol (IPv6),
   also sometimes referred to as IP Next Generation or IPng.


1.  Introduction

   IP version 6 (IPv6) is a new version of the Internet Protocol,
   designed as a successor to IP version 4 (IPv4) [RFC-791].  The
   changes from IPv4 to IPv6 fall primarily into the following
   categories:

      o  Expanded Addressing Capabilities

         IPv6 increases the IP address size from 32 bits to 128 bits, to
         support more levels of addressing hierarchy, a much greater
         number of addressable nodes, and simpler auto-configuration of
         addresses.  The scalability of multicast routing is improved by
         adding a "scope" field to multicast addresses.  And a new type
         of address called an "anycast address" is defined, used to send
         a packet to any one of a group of nodes.

      o  Header Format Simplification

         Some IPv4 header fields have been dropped or made optional, to
         reduce the common-case processing cost of packet handling and
         to limit the bandwidth cost of the IPv6 header.

      o  Improved Support for Extensions and Options

         Changes in the way IP header options are encoded allows for
         more efficient forwarding, less stringent limits on the length
         of options, and greater flexibility for introducing new options
         in the future.

      o  Flow Labeling Capability

         A new capability is added to enable the labeling of packets
         belonging to particular traffic "flows" for which the sender
         requests special handling, such as non-default quality of
         service or "real-time" service.

      o  Authentication and Privacy Capabilities

         Extensions to support authentication, data integrity, and
         (optional) data confidentiality are specified for IPv6.

   This document specifies the basic IPv6 header and the initially-
   defined IPv6 extension headers and options.  It also discusses packet
   size issues, the semantics of flow labels and priority, and the
   effects of IPv6 on upper-layer protocols.  The format and semantics
   of IPv6 addresses are specified separately in [RFC-1884].  The IPv6
   version of ICMP, which all IPv6 implementations are required to
   include, is specified in [RFC-1885].


2.  Terminology(以下，略)

References

   [RFC-1885]   Conta, A., and S. Deering, "Internet Control Message
                Protocol (ICMPv6) for the Internet Protocol Version 6
                (IPv6) Specification", RFC 1885, Digital Equipment
                Corporation, Xerox PARC, December 1995.

   [RFC-1884]   Hinden, R., and S. Deering, Editors, "IP Version 6
                Addressing Architecture", RFC 1884, Ipsilon Networks,
                Xerox PARC, December 1995.

   [RFC-791]    Postel, J., "Internet Protocol", STD 5, RFC 791,
                USC/Information Sciences Institute, September 1981.