Internet Engineering Task Force J. Palet Internet-Draft Consulintel Expires: April 19, 2006 October 16, 2005 6in4 versus 6over4 terminology draft-palet-v6ops-6in4-vs-6over4-00.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on April 19, 2006. Copyright Notice Copyright (C) The Internet Society (2005). Abstract This document clarifies the existing terminology confusion among references to IPv6/IPv4 encapsulations and IPv4/IPv6 transition mechanisms. Palet Expires April 19, 2006 [Page 1] Internet-Draft 6in4 versus 6over4 terminology October 2005 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Definition of 'in' and 'over' . . . . . . . . . . . . . . . . . 4 3. Conclusions and Future Consistency . . . . . . . . . . . . . . 4 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 7.1. Normative References . . . . . . . . . . . . . . . . . . . 5 7.2. Informative References . . . . . . . . . . . . . . . . . . 6 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 7 Intellectual Property and Copyright Statements . . . . . . . . . . 8 Palet Expires April 19, 2006 [Page 2] Internet-Draft 6in4 versus 6over4 terminology October 2005 1. Introduction A number of IETF documents have used in an "interchangeable" way several expressions such as: o 6in4 o 6-in-4 o IPv6-in-IPv4 o IPv6 in IPv4 o 6over4 o 6-over-4 o IPv6-over-IPv4 o IPv6 over IPv4 o 4in6 o 4-in-6 o IPv4-in-IPv6 o IPv4 in IPv6 o 4over6 o 4-over-6 o IPv4-over-IPv6 o IPv4 over IPv6 Note that this list is not exhaustive and many other similar expressions may be also in use. For example, in some situations other encapsulating layers are used (i.e., 6/UDP/4), and similar expressions are being used. As a consequence, documents from vendors, product manuals, publications, papers, books, tutorials, training material and many others, use also those expressions. However not all those documents, including the IETF ones, are actually referring to the same IPv6/IPv4 encapsulations or IPv4/IPv6 Palet Expires April 19, 2006 [Page 3] Internet-Draft 6in4 versus 6over4 terminology October 2005 transition mechanisms. The result of this terminology confusion is a number of errors among vendors, operators, engineers and users when designing and documenting products, or when setting up transition mechanisms, creating at the end unnecessary operational costs, specially for beginners which try to setup IPv6 for their first occasions. 2. Definition of 'in' and 'over' IP in IP Tunneling was defined by [1]. Afterwards [2], obsoleted by [3], defines the basic IPv4/IPv6 transition mechanisms, including the encapsulation of IPv6 packets in IPv4 ones (by means of protocol 41); this document is being updated as "ietf-v6ops-mech-v2". Similarly, [4], defines the encapsulation of IPv4 packets in IPv6 ones. A first conclusion can be extracted from this documents (even if some of them actually use, some times, "over"): Those encapsulation mechanisms are the ones that should use the "in" terminology. Note that they are just encapsulation mechanisms, which often are used by several transition mechanisms. Furthermore, [5] specify a transition mechanism, which uses 6in4 (encapsulation of IPv6 packets in IPv4 ones), creating a virtual IPv6 link over an IPv4 multicast infrastructure. This transition mechanism is named as "6over4". Clearly, "6in4" and "6over4" are quite different things, actually 6over4 is a transition mechanism which uses 6in4 as the procedure for encapsulating IPv6 packets in IPv4 multicast infrastructures. The fact that they are different things and specially the requirement for a (IPv4) multicast infrastructure for 6over4, makes necessary to clarify the difference and avoid confusions among both. Engineers operating networks and their customers (for example when setting up tunnels), often do not read all the IETF documents, so they could easily misunderstand if a tunnel is "6over4" or "6in4" (specially when vendor documents use both terms to actually name "6in4", possibly because the misusage of those terms in [2], [3]), and this creates some extra troubleshooting time and confusion. 3. Conclusions and Future Consistency Palet Expires April 19, 2006 [Page 4] Internet-Draft 6in4 versus 6over4 terminology October 2005 In order to avoid this kind of confusion, it should be understood the difference between 6over4 and 6in4 (and any other equivalent terminologies), and future documents (including IETF ones) must take this in consideration when republished. Moreover, new documents which describe other encapsulations and protocols, such as IPv4 in IPv6, IPv6 in UDP/IPv4, IPv6 in IPv6, must also use, for consistency reasons, "in" instead of "over". It is recommended that any existing documents are amended ASAP to avoid the existing confusion. 4. Security Considerations This document does not have any protocol-related security considerations. 5. IANA Considerations This document does not have any specific IANA considerations. 6. Acknowledgements The author would like to acknowledge the inputs of ... 7. References 7.1. Normative References [1] Simpson, W., "IP in IP Tunneling", RFC 1853, October 1995. [2] Gilligan, R. and E. Nordmark, "Transition Mechanisms for IPv6 Hosts and Routers", RFC 1933, April 1996. [3] Gilligan, R. and E. Nordmark, "Transition Mechanisms for IPv6 Hosts and Routers", RFC 2893, August 2000. [4] Conta, A. and S. Deering, "Generic Packet Tunneling in IPv6 Specification", RFC 2473, December 1998. [5] Carpenter, B. and C. Jung, "Transmission of IPv6 over IPv4 Domains without Explicit Tunnels", RFC 2529, March 1999. Palet Expires April 19, 2006 [Page 5] Internet-Draft 6in4 versus 6over4 terminology October 2005 7.2. Informative References Palet Expires April 19, 2006 [Page 6] Internet-Draft 6in4 versus 6over4 terminology October 2005 Author's Address Jordi Palet Martinez Consulintel San Jose Artesano, 1 Alcobendas - Madrid E-28108 - Spain Phone: +34 91 151 81 99 Fax: +34 91 151 81 98 Email: jordi.palet@consulintel.es Palet Expires April 19, 2006 [Page 7] Internet-Draft 6in4 versus 6over4 terminology October 2005 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. 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Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Copyright Statement Copyright (C) The Internet Society (2005). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Palet Expires April 19, 2006 [Page 8]