[Docs] [txt|pdf] [Tracker] [Email] [Diff1] [Diff2] [Nits]

Versions: 00 01

Internet Engineering Task Force                                 J. Palet
Internet-Draft                                               Consulintel
Expires: May 20, 2006                                  November 16, 2005


                     6in4 versus 6over4 terminology
                draft-palet-v6ops-6in4-vs-6over4-01.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 May 20, 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 May 20, 2006                  [Page 1]


Internet-Draft       6in4 versus 6over4 terminology        November 2005


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Definition of 'in' and 'over' . . . . . . . . . . . . . . . . . 4
   3.  Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . 5
   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 May 20, 2006                  [Page 2]


Internet-Draft       6in4 versus 6over4 terminology        November 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 well.

   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 May 20, 2006                  [Page 3]


Internet-Draft       6in4 versus 6over4 terminology        November 2005


   transition mechanisms.

   The result of this terminology confusion is a number of errors among
   vendors, operators, engineers and end-users when designing and
   documenting products, or when setting up transition mechanisms, being
   the cause of 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".  This name was chosen because the
   mechanism (use of IPv4 multicast for Neighbor Discovery) is exactly
   analogous to the mechanism for IPv6 over Ethernet (use of Ethernet
   multicast for Neighbor Discovery).

   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.




Palet                     Expires May 20, 2006                  [Page 4]


Internet-Draft       6in4 versus 6over4 terminology        November 2005


3.  Conclusions

   In order to avoid this kind of confusion, it should be understood the
   difference between 6over4 and 6in4 (and any other equivalent
   terminologies).  Future documents should take this in consideration.

   It is recommended as well that new documents which describe other
   encapsulations and protocols, such as IPv4 in IPv6, IPv6 in UDP/IPv4,
   IPv6 in IPv6, etc., for consistency reasons, use "in" instead of
   "over".

   It is also recommended that 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 Brian Carpenter.


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 May 20, 2006                  [Page 5]


Internet-Draft       6in4 versus 6over4 terminology        November 2005


7.2.  Informative References


















































Palet                     Expires May 20, 2006                  [Page 6]


Internet-Draft       6in4 versus 6over4 terminology        November 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 May 20, 2006                  [Page 7]


Internet-Draft       6in4 versus 6over4 terminology        November 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.

   Copies of IPR disclosures made to the IETF Secretariat and any
   assurances of licenses to be made available, or the result of an
   attempt made to obtain a general license or permission for the use of
   such proprietary rights by implementers or users of this
   specification can be obtained from the IETF on-line IPR repository at
   http://www.ietf.org/ipr.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights that may cover technology that may be required to implement
   this standard.  Please address the information to the IETF at
   ietf-ipr@ietf.org.


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 May 20, 2006                  [Page 8]


Html markup produced by rfcmarkup 1.121, available from https://tools.ietf.org/tools/rfcmarkup/