Address Mapping of IPv6 Multicast Packets on Ethernet
Clarifies that an IPv6 multicast packet may be sent in an Ethernet unicast frame when only one receiver matters.
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, <https://www.rfc-editor.org/info/rfc6085>.
@misc{rfc6085,
series = {Request for Comments},
number = 6085,
howpublished = {RFC 6085},
publisher = {RFC Editor},
doi = {10.17487/RFC6085},
url = {https://www.rfc-editor.org/info/rfc6085},
author = {S. Gundavelli and M. Townsley and O. Troan and W. Dec},
title = {{Address Mapping of IPv6 Multicast Packets on Ethernet}},
pagetotal = 3,
year = 2011,
month = jan,
} RFC text
Contents
Internet Engineering Task Force (IETF) S. Gundavelli
Request for Comments: 6085 M. Townsley
Updates: 2464 O. Troan
Category: Standards Track W. Dec
ISSN: 2070-1721 Cisco
January 2011
Address Mapping of IPv6 Multicast Packets on Ethernet
Abstract
When transmitting an IPv6 packet with a multicast destination
address, the IPv6 destination address is mapped to an Ethernet link-
layer multicast address. This document clarifies that a mapping of
an IPv6 packet with a multicast destination address may in some
circumstances map to an Ethernet link-layer unicast address.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6085.
Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
1. Introduction
"Transmission of IPv6 Packets over Ethernet Networks" ([RFC2464],
Section 7) specifies how an IPv6 packet with a multicast destination
address is mapped into an Ethernet link-layer address. This document
extends this mapping to explicitly allow for a mapping of an IPv6
packet with a multicast destination address into an Ethernet link-
layer unicast address, when it is clear that only one address is
relevant.
This mapping does not replace the mapping described in [RFC2464],
Section 7. The determination of the unicast Ethernet link-layer
address and the construction of the outgoing IPv6 packet are out of
scope for this document.
2. Conventions
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 RFC 2119 [RFC2119].
3. Receiving IPv6 Multicast Packets
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 of the use of this form of address mapping.
4. Security Considerations
This document does not introduce any new security vulnerabilities.
5. Acknowledgements
The authors would like to acknowledge Bernard Aboba, Fred Baker, Wes
Beebee, Ron Bonica, Olaf Bonness, Jean-Michel Combes, Ralph Droms,
Alain Durand, Suresh Krishnan, Eric Levy-Abegnoli, Phil Roberts,
Behcet Sarikaya, Hemant Singh, Mark Smith, Dave Thaler, Pascal
Thubert, Stig Venaas, and Eric Voit for their contributions and
discussions on this topic.
6. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet
Networks", RFC 2464, December 1998.
Authors' Addresses
Sri Gundavelli
Cisco
170 West Tasman Drive
San Jose, CA 95134
USA
EMail: sgundave@cisco.com
Mark Townsley
Cisco
L'Atlantis, 11, Rue Camille Desmoulins
ISSY LES MOULINEAUX, ILE DE FRANCE 92782
France
EMail: townsley@cisco.com
Ole Troan
Cisco
Oslo,
Norway
EMail: ot@cisco.com
Wojciech Dec
Cisco
Haarlerbergweg 13-19
Amsterdam, Noord-Holland 1101 CH
Netherlands
EMail: wdec@cisco.com
AI ELI5
On this page
§1Introduction
Section 7 of RFC 2464 says how an IPv6 packet with a multicast destination address is mapped to an Ethernet link-layer address. This document extends that mapping to explicitly allow an Ethernet unicast address, when it is clear that only one address is relevant.
The new mapping does not replace the RFC 2464 one. How the unicast Ethernet address is determined, and how the outgoing IPv6 packet is built, are out of scope.
Group messages normally go to the group's mailbox. Now they may go to one person's mailbox if only that person needs them.
§2Receiving Such Packets
The one rule is for receivers: an IPv6 node that receives a packet with a multicast destination address and an Ethernet link-layer unicast address MUST NOT drop the packet because of this form of address mapping.
If a group message arrives addressed to you alone, do not throw it away just for that.
§3Security Considerations
The document states that it does not introduce any new security vulnerabilities. It offers no further analysis.
Nothing new that could go wrong was found.