Transmission of IPv6 Packets over Ethernet Networks
RFC 2464

Document Type RFC - Proposed Standard (December 1998; Errata)
Updated by RFC 8064, RFC 6085
Obsoletes RFC 1972
Author Matt Crawford 
Last updated 2020-01-21
Stream Internent Engineering Task Force (IETF)
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Network Working Group                                        M. Crawford
Request for Comments: 2464                                      Fermilab
Obsoletes: 1972                                            December 1998
Category: Standards Track

          Transmission of IPv6 Packets over Ethernet Networks

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 (1998).  All Rights Reserved.

1.  Introduction

   This document specifies the frame format for transmission of IPv6
   packets and the method of forming IPv6 link-local addresses and
   statelessly autoconfigured addresses on Ethernet networks.  It also
   specifies the content of the Source/Target Link-layer Address option
   used in Router Solicitation, Router Advertisement, Neighbor
   Solicitation, Neighbor Advertisement and Redirect messages when those
   messages are transmitted on an Ethernet.

   This document replaces RFC 1972, "A Method for the Transmission of
   IPv6 Packets over Ethernet Networks", which will become historic.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in [RFC 2119].

2.  Maximum Transmission Unit

   The default MTU size for IPv6 [IPV6] packets on an Ethernet is 1500
   octets.  This size may be reduced by a Router Advertisement [DISC]
   containing an MTU option which specifies a smaller MTU, or by manual
   configuration of each node.  If a Router Advertisement received on an
   Ethernet interface has an MTU option specifying an MTU larger than
   1500, or larger than a manually configured value, that MTU option may
   be logged to system management but must be otherwise ignored.

Crawford                    Standards Track                     [Page 1]
RFC 2464               IPv6 Packets over Ethernet          December 1998

   For purposes of this document, information received from DHCP is
   considered "manually configured" and the term Ethernet includes
   CSMA/CD and full-duplex subnetworks based on ISO/IEC 8802-3, with
   various data rates.

3.  Frame Format

   IPv6 packets are transmitted in standard Ethernet frames.  The
   Ethernet header contains the Destination and Source Ethernet
   addresses and the Ethernet type code, which must contain the value
   86DD hexadecimal.  The data field contains the IPv6 header followed
   immediately by the payload, and possibly padding octets to meet the
   minimum frame size for the Ethernet link.

                     0                   1
                     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
                    |          Destination          |
                    +-                             -+
                    |            Ethernet           |
                    +-                             -+
                    |            Address            |
                    |             Source            |
                    +-                             -+
                    |            Ethernet           |
                    +-                             -+
                    |            Address            |
                    |1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1|
                    |             IPv6              |
                    +-                             -+
                    |            header             |
                    +-                             -+
                    |             and               |
                    +-                             -+
                    /            payload ...        /

                    (Each tic mark represents one bit.)

Crawford                    Standards Track                     [Page 2]
RFC 2464               IPv6 Packets over Ethernet          December 1998

4.  Stateless Autoconfiguration

   The Interface Identifier [AARCH] for an Ethernet interface is based
   on the EUI-64 identifier [EUI64] derived from the interface's built-
   in 48-bit IEEE 802 address.  The EUI-64 is formed as follows.
   (Canonical bit order is assumed throughout.)

   The OUI of the Ethernet address (the first three octets) becomes the
   company_id of the EUI-64 (the first three octets).  The fourth and
   fifth octets of the EUI are set to the fixed value FFFE hexadecimal.
   The last three octets of the Ethernet address become the last three
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