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. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on September 14, 2017. Copyright Notice Copyright (c) 2017 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 Crawford & Hinden Expires September 14, 2017 [Page 1] Internet-Draft IPv6 Packets over Ethernet March 2017 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. This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English. 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. Crawford & Hinden Expires September 14, 2017 [Page 2] Internet-Draft IPv6 Packets over Ethernet March 2017 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. Crawford & Hinden Expires September 14, 2017 [Page 3] Internet-Draft IPv6 Packets over Ethernet March 2017 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. Crawford & Hinden Expires September 14, 2017 [Page 4] Internet-Draft IPv6 Packets over Ethernet March 2017 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 Crawford & Hinden Expires September 14, 2017 [Page 5] Internet-Draft IPv6 Packets over Ethernet March 2017 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: Crawford & Hinden Expires September 14, 2017 [Page 6] Internet-Draft IPv6 Packets over Ethernet March 2017 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 Crawford & Hinden Expires September 14, 2017 [Page 7] Internet-Draft IPv6 Packets over Ethernet March 2017 12.1. Normative References [ACONF] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless Address Autoconfiguration", RFC 4862, DOI 10.17487/ RFC4862, September 2007, . [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, . [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, . [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, . 12.2. Informative References [EUI64] "IEEE, "Guidelines for 64-bit Global Identifier (EUI-64) Registration Authority"", March 1997, . [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, . Crawford & Hinden Expires September 14, 2017 [Page 8] Internet-Draft IPv6 Packets over Ethernet March 2017 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 Crawford & Hinden Expires September 14, 2017 [Page 9]