Network Working Group J. Abley Internet-Draft ISC Expires: January 11, 2006 July 10, 2005 Shim6 Applicability Statement draft-ietf-shim6-applicability-00 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 January 11, 2006. Copyright Notice Copyright (C) The Internet Society (2005). Abstract This document discusses the applicability of the Shim6 IPv6 protocol element and associated support protocols to provide site multihoming capabilities in IPv6. Note on Shim6 Maturity Shim6 is a work in progress, and does not currently meet the maturity requirements for advancement to Proposed Standard. Abley Expires January 11, 2006 [Page 1] Internet-Draft Shim6 Applicability Statement July 2005 A summary of the maturity of the various technical specifications that accompany this document can be found in Section 6. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Architectural Overview . . . . . . . . . . . . . . . . . . . . 3 3. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Implementations . . . . . . . . . . . . . . . . . . . . . . . 3 5. Operational Experience . . . . . . . . . . . . . . . . . . . . 4 6. Maturity Assessment . . . . . . . . . . . . . . . . . . . . . 4 7. Security Considerations . . . . . . . . . . . . . . . . . . . 4 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 4 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 4 10.1 Normative References . . . . . . . . . . . . . . . . . . . 4 10.2 Informative References . . . . . . . . . . . . . . . . . . 4 Author's Address . . . . . . . . . . . . . . . . . . . . . . . 5 A. Change History . . . . . . . . . . . . . . . . . . . . . . . . 5 Intellectual Property and Copyright Statements . . . . . . . . 6 Abley Expires January 11, 2006 [Page 2] Internet-Draft Shim6 Applicability Statement July 2005 1. Introduction Site multi-homing is an arrangement by which a site may use multiple paths to the rest of the Internet, to provide better reliability for traffic passing in and out of the site than would be possible with a single path. Some of the motivations for operators to multi-home their network are described in [RFC3582]. In IPv4, site multi-homing is achieved by introducing the additional state required to allow session resilience over re-homing events to the global Internet routing system (sometimes referred to as the Default-Free Zone, or DFZ) [I-D.ietf-multi6-v4-multihoming]. There is concern that this approach will not scale [RFC3221]. In IPv6, site multi-homing in the style of IPv4 is not generally available to end sites due to a strict route aggregation in the DFZ, coupled with Regional Internet Registry (RIR) allocation policies which prohibit the direct assignment of provider-independent (PI) addresses to most end users. Site multi-homing for sites without PI addresses is achieved by assigning multiple addresses to each host, one from each provider. This multi-homing approach provides no transport-layer stability across re-homing events. Shim6 introduces transport-layer mobility across re-homing events using a layer-3 shim approach. State information relating to the multi-homing of two endpoints exchanging unicast traffic is retained on the endpoints themselves, rather than in the network. Communications between shim6-capable hosts and shim6-incapable hosts proceed as normal, but without the benefit of transport-layer stability. The Shim6 approach is thought to have better scaling properties than the IPv4 approach, at the expense of somewhat reduced operational capability. 2. Architectural Overview A general architectural overview of Shim6 will be included here. In the absense of useful text in this section, readers may wish to refer to [I-D.ietf-shim6-arch]. 3. Applicability A list of shim6 technical specifications will go here, each with a requirements level, per [RFC2026]. 4. Implementations There is no known implementation of Shim6. Abley Expires January 11, 2006 [Page 3] Internet-Draft Shim6 Applicability Statement July 2005 5. Operational Experience There is no known operational experience of Shim6. 6. Maturity Assessment Shim6 is not sufficiently mature at the time of writing to be advanced to Proposed Standard [RFC2026]. The following is a list of possible work remaining before such advancement might be sought: o The Shim6 technical specifications enumerated in this document are not yet stable. o The Shim6 technical specifications have yet to resolve all known design choices. o The extent to which the Shim6 architecture is well-understood has yet to be thoroughly gauged. o There is no Management Information Base (MIB) available for Shim6. o There is neither implementation nor operational experience of Shim6. o The Shim6 architecture has known technical ommissions. 7. Security Considerations Security considerations go here. 8. IANA Considerations IANA considerations go here. 9. Acknowledgements This work was supported by the US National Science Foundation (research grant SCI-0427144) and DNS-OARC. 10. References 10.1 Normative References [I-D.ietf-shim6-arch] Huston, G., "Architectural Commentary on Site Multi-homing using a Level 3 Shim", draft-ietf-shim6-arch-00 (work in progress), July 2005. 10.2 Informative References [I-D.ietf-multi6-v4-multihoming] Abley, J., Black, B., and V. Gill, "IPv4 Multihoming Practices and Limitations", Abley Expires January 11, 2006 [Page 4] Internet-Draft Shim6 Applicability Statement July 2005 draft-ietf-multi6-v4-multihoming-03 (work in progress), January 2005. [RFC2026] Bradner, S., "The Internet Standards Process -- Revision 3", BCP 9, RFC 2026, October 1996. [RFC3221] Huston, G., "Commentary on Inter-Domain Routing in the Internet", RFC 3221, December 2001. [RFC3582] Abley, J., Black, B., and V. Gill, "Goals for IPv6 Site- Multihoming Architectures", RFC 3582, August 2003. Author's Address Joe Abley Internet Systems Consortium, Inc. 950 Charter Street Redwood City, CA 94063 US Phone: +1 650 423 1317 Email: jabley@isc.org Appendix A. Change History This section should be removed prior to publication. draft-ietf-shim6-applicability-00: First draft, largely incomplete, submitted to facilitate comments on general structure and approach. Abley Expires January 11, 2006 [Page 5] Internet-Draft Shim6 Applicability Statement July 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. Abley Expires January 11, 2006 [Page 6]