INTERNET-DRAFT Donald Eastlake 3rd UPDATES BCP 37 / RFC 2780 Motorola Scott Bradner Harvard University Expires: January 2001 July 2000 Extended IP Versions -------- -- -------- Status of This Document Distribution of this draft, which is intended to become part of Best Current Practice 37, is unlimited. Comments should be sent to the authors. This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC 2026. 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. Copyright Notice Copyright (C) The Internet Society (2000). All Rights Reserved. Abstract The current four bit Internet Protocol (IP) Version field provides for such a limited number of versions that very tight control must be exercised on their allocation as documented in [RFC 2780]. Provisions are specified whereby one value of that field is extended to provide ample easily allocated values. D. Eastlake 3rd, S. Bradner [Page 1] INTERNET-DRAFT Extended IP Versions July 2000 Table of Contents Status of This Document....................................1 Copyright Notice...........................................1 Abstract...................................................1 Table of Contents..........................................2 1. Introduction............................................3 2. Extended IP Versions....................................3 3. IANA Considerations.....................................4 4. Security Considerations.................................4 References.................................................5 Authors Addresses..........................................5 Full Copyright Statement...................................6 Expiration and File Name...................................6 D. Eastlake 3rd, S. Bradner [Page 2] INTERNET-DRAFT Extended IP Versions July 2000 1. Introduction Since the begining of the Internet Protocol (IP), it has had a four bit version field. This was entirely adequate in the early days when the Internet engineering community was tiny and went fairly rapdily through version 1, 2, and 3, before stabilizing on version 4 (IPv4) under which the Internet has prospered [RFC 791]. Recently, when a need was felt for specification of a new version, the remaining version number space was barely adequate to assign versions to the main contenders, leading to the selection of IPv6 as the main path [RFC 2460]. Furthermore, the Internet engineering community has grown by over two orders of magnitude since the specification of IP, with IETF attendence going from 15 to 3000 potentially increasing demand for experimental parameter values. To continue the successful tradition of easy free availability of parameter values, IP version numbers need to be extended. How beneficial this will be in this particular case is unclear. But if the prospering of Internet Technology has taught us anything, it is that easy free availability of parameter values can lead to surprising creativity and vigor. Perhaps this mechanism will do that or perhaps it will turn out to be almost unused, like the DNS Class mechanism. But the cost is small and the potential benefit hard to bound. An equivalent 4 bit IP version number can be allocated for any extended IP version, when warranted, under the IP version allocation procedure specified in [RFC 2780]. 2. Extended IP Versions The Internet Protocol packet format is defined to begin with a four bit Version as follows: 0 0 1 2 3 4 5 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Version| ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ To extend this versioning mechanism, this document specifies that the version number (TBD (suggest 1)) is followed by a four bit Extension Type as shown below. It is intended that further information later in the packet, depending on the extension type, indicate the exact extended version. D. Eastlake 3rd, S. Bradner [Page 3] INTERNET-DRAFT Extended IP Versions July 2000 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | (TBD) |ExtType| ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Extension type 1 is allocated for an ample supply of First Come First Served, easy to obtain, extended IP verison numbers, as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | (TBD) | 1 | extension type 1 subverion number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The subversion number is considered an unsigned integer in network byte order in the range 0 - 16,777,215 assigned sequentially. This structure causes the remainder of the IP packet to be 32 bit aligned. 3. IANA Considerations IP Version number (TBD (suggest 1)) is allocated for extended IP Versions as documnted herein. IP extention type 1 is allocated as specified herein. Allocation of other IP extension types requires an "IESG approval" or "Standards Action" as defined in RFC 2434. Specific three byte extension values of type one are allocated sequentially on a First Come First Served basis. 4. Security Considerations Firwalls or other software which wishes to pass only packets they understand should block all IP version extension types and specific extension values that are not kown to them. D. Eastlake 3rd, S. Bradner [Page 4] INTERNET-DRAFT Extended IP Versions July 2000 References [RFC 791] - "Internet Protocol", J. Postel, September 1981. [RFC 2434] - "Guidelines for Writing an IANA Considerations Section in RFCs", T. Narten, H. Alvestrand, October 1998. [RFC 2460] - "Internet Protocol, Version 6 (IPv6) Specification", Deering, S. and R. Hinden, December 1998. [RFC 2780] - "IANA Allocation Guidelines For Values In the Internet Protocol and Related Headers", S. Bradner, V. Paxon, March 2000. Authors Addresses Scott Bradner Harvard University Cambridge, MA 02138 USA Telephone: +1 617 495 3864 EMail: sob@harvard.edu Donald E. Eastlake 3rd Motorola 140 Forest Avenue Hudson, MA 01749 USA Telephone: +1-978-562-2827 (h) +1-508-261-5434 (w) FAX: +1-508-261-4447 (w) EMail: Donald.Eastlake@motorola.com D. Eastlake 3rd, S. Bradner [Page 5] INTERNET-DRAFT Extended IP Versions July 2000 Full Copyright Statement Copyright (C) The Internet Society (2000). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS 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. Expiration and File Name This draft expires Janaury 2001. Its file name is draft-eastlake-ext-ip-ver-00.txt. D. Eastlake 3rd, S. Bradner [Page 6]