Internet DRAFT - draft-hinden-6man-rfc2464bis
draft-hinden-6man-rfc2464bis
Network Working Group M. Crawford
Internet-Draft Fermilab
Obsoletes: 2464 (if approved) R. Hinden, Ed.
Intended status: Standards Track Check Point Software
Expires: September 14, 2017 March 13, 2017
Transmission of IPv6 Packets over Ethernet Networks
draft-hinden-6man-rfc2464bis-02
Abstract
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 2464 "Transmission of IPv6 Packets over
Ethernet Networks", which will become historic.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on September 14, 2017.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Maximum Transmission Unit . . . . . . . . . . . . . . . . . . 3
3. Frame Format . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Stateless Autoconfiguration . . . . . . . . . . . . . . . . . 4
5. Link-Local Addresses . . . . . . . . . . . . . . . . . . . . 5
6. Address Mapping -- Unicast . . . . . . . . . . . . . . . . . 5
7. Address Mapping -- Multicast . . . . . . . . . . . . . . . . 5
8. Differences from RFC 4291 . . . . . . . . . . . . . . . . . . 6
9. Differences From RFC 1972 . . . . . . . . . . . . . . . . . . 7
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
11. Security Considerations . . . . . . . . . . . . . . . . . . . 7
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
12.1. Normative References . . . . . . . . . . . . . . . . . . 8
12.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
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.
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This document replaces RFC 2464 "Transmission of IPv6 Packets over
Ethernet Networks", which will become historic.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
2. Maximum Transmission Unit
The default MTU size for IPv6 [I-D.ietf-6man-rfc2460bis] 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.
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.
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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.)
4. Stateless Autoconfiguration
The default approach to create stable Interface Identifiers
[I-D.ietf-6man-rfc4291bis] for use with SLAAC on an Ethernet
interface should be based on [RFC7217].
It is not recommended that Interface Identifiers for an Ethernet
interface be based on stable IEEE MAC-layer addresses. Earlier
versions of this document described a method of forming interface
identifiers derived from stable IEEE MAC-layer addresses called
Modified EUI-64 format. This is described in Appendix A of
[I-D.ietf-6man-rfc4291bis] and is no longer recommended. The
approach described in this appendix may be used to create Interface
Identifiers based on non-stable (e.g., random) IEEE Mac-layer
addresses. See [XXX] for more information non-stable IEEE Mac-layer
addresses.
An IPv6 address prefix used for stateless autoconfiguration [ACONF]
of an Ethernet interface must have a length of 64 bits.
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5. Link-Local Addresses
The IPv6 link-local address [I-D.ietf-6man-rfc4291bis] for an
Ethernet interface is formed by appending the Interface Identifier,
as defined above, to the prefix FE80::/64.
10 bits 54 bits 64 bits
+----------+-----------------------+----------------------------+
|1111111010| (zeros) | Interface Identifier |
+----------+-----------------------+----------------------------+
6. Address Mapping -- Unicast
The procedure for mapping IPv6 unicast addresses into Ethernet link-
layer addresses is described in [DISC]. The Source/Target Link-layer
Address option has the following form when the link layer is
Ethernet.
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+- Ethernet -+
| |
+- Address -+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option fields:
Type 1 for Source Link-layer address.
2 for Target Link-layer address.
Length 1 (in units of 8 octets).
Ethernet Address The 48 bit Ethernet IEEE 802 address, in
canonical bit order. This is the address the
interface currently responds to, and may be
different from the built-in address used to
derive the Interface Identifier.
7. Address Mapping -- Multicast
An IPv6 packet with a multicast destination address DST, consisting
of the sixteen octets DST[1] through DST[16], is transmitted to the
Ethernet multicast address whose first two octets are the value 3333
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hexadecimal and whose last four octets are the last four octets of
DST.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 1 1 0 0 1 1|0 0 1 1 0 0 1 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DST[13] | DST[14] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DST[15] | DST[16] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
An IPv6 multicast packet may also be mapped to a unicast Ethernet
Link layer address as defined in [RFC6085].
An IPv6 node receiving an IPv6 packet with a multicast destination
address and an Ethernet link-layer unicast address must not drop the
packet as a result using of this form of address mapping.
8. Differences from RFC 4291
This document has the following changes from RFC2464, "Transmission
of IPv6 Packets over Ethernet Networks ". Numbers identify the
Internet-Draft version that the change was made.:
Individual Internet Drafts
02) Clarified the recommendation in Section 4 that it is not
recommending the use of stable link-layer addresses to create
IIDs, and that it is OK to use non-stable link-layer
addresses.
02) Added reference to RFC6085 in Section 7.
02) Editorial changes.
01) Incorporate update from RFC8064. Revised Section 4 to say
IIDs should be formed based on RFC7217 and that it not
recommended to use hardware based IIDs.
01) Incorporate update from RFC6085. Added to Section 7 that an
IPv6 multicast packet may be mapped to a unicast Ethernet
Link layer address and that nodes receiving packets with this
address mapping should not drop these packets.
01) Updates to resolve the open Errata on RFC2464. These are:
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Errata ID: 430: Correct reference to EUI-64. Note, the
corrected URL specified in the Errata isn't working, the
reference now points to one that does work.
Errata ID: 4855: This errata is not correct, and will be
marked as rejected. No change is required. Also, the
text that this Errata proposed to change was removed when
the update from draft-ietf-6man-default-iids was
incorporated.
01) Editorial changes.
00) Establish a baseline from RFC2464. The only intended changes
are formatting (XML is slightly different from .nroff),
differences between an RFC and Internet Draft, fixing a few
ID Nits, and updates to the authors information. There
should not be any content changes to the specification.
9. Differences From RFC 1972
The following are the functional differences between this
specification and RFC 1972.
The Address Token, which was a node's 48-bit MAC address, is
replaced with the Interface Identifier, which is 64 bits in length
and based on the EUI-64 format [EUI64]. An IEEE-defined mapping
exists from 48-bit MAC addresses to EUI-64 form.
A prefix used for stateless autoconfiguration must now be 64 bits
long rather than 80. The link-local prefix is also shortened to
64 bits.
10. IANA Considerations
This document does not have any IANA actions.
11. Security Considerations
The method of derivation of Interface Identifiers from MAC addresses
is intended to preserve global uniqueness when possible. However,
there is no protection from duplication through accident or forgery.
12. References
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12.1. Normative References
[ACONF] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862, DOI 10.17487/
RFC4862, September 2007,
<http://www.rfc-editor.org/info/rfc4862>.
[DISC] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
DOI 10.17487/RFC4861, September 2007,
<http://www.rfc-editor.org/info/rfc4861>.
[I-D.ietf-6man-rfc2460bis]
Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", draft-ietf-6man-rfc2460bis-08 (work
in progress), November 2016.
[I-D.ietf-6man-rfc4291bis]
Hinden, R. and S. <>, "IP Version 6 Addressing
Architecture", draft-ietf-6man-rfc4291bis-07 (work in
progress), January 2017.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC7217] Gont, F., "A Method for Generating Semantically Opaque
Interface Identifiers with IPv6 Stateless Address
Autoconfiguration (SLAAC)", RFC 7217, DOI 10.17487/
RFC7217, April 2014,
<http://www.rfc-editor.org/info/rfc7217>.
12.2. Informative References
[EUI64] "IEEE, "Guidelines for 64-bit Global Identifier (EUI-64)
Registration Authority"", March 1997,
<http://standards.ieee.org/develop/regauth/tut/eui64.pdf>.
[RFC6085] Gundavelli, S., Townsley, M., Troan, O., and W. Dec,
"Address Mapping of IPv6 Multicast Packets on Ethernet",
RFC 6085, DOI 10.17487/RFC6085, January 2011,
<http://www.rfc-editor.org/info/rfc6085>.
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Authors' Addresses
Matt Crawford
Fermilab
PO Box 500
Batavia, IL 60510
USA
Email: crawdad@fnal.gov
Robert M. Hinden (editor)
Check Point Software
959 Skyway Road
San Carlos, CA 94070
USA
Email: bob.hinden@gmail.com
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