DHC WG Ma Yuzhi Internet Draft Huawei Technologies CO.,LTD Expires: April 12, 2006 October 13, 2005 Home Agent Configuration Option for DHCPv6 draft-yuchi-dhc-homeagent-option-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 13, 2006. Copyright Notice Copyright (C) The Internet Society (2005). All Rights Reserved. Abstract This document defines a new home agent option for the Dynamic Host Configuration Protocol for IPv6 (DHCPv6). To assist with rapid Ma Expires April 13, 2006 [Page 1] Internet-Draft Home Agent Configuration Option October 2005 handovers the option allows a mobile node (DHCPv6 client) to acquire a list of home agent addresses from a DHCPv6 server. Table of Contents 1. Introduction.................................................2 2. Terminology..................................................3 3. Home Agent Option............................................3 4. Client behavior..............................................4 5. Server behavior..............................................4 6. Relay agent behavior.........................................5 7. IANA Considerations..........................................5 8. Security Considerations......................................5 9. Acknowledgments..............................................5 10. References..................................................6 10.1. Normative References...................................6 10.2. Informative References.................................6 Author's Addresses..............................................6 Intellectual Property Statement.................................6 Disclaimer of Validity..........................................7 Copyright Statement.............................................7 Acknowledgment..................................................7 1. Introduction In Mobile IPv6, a mobile node needs to acquire its home address, care-of address and home agent addresses. While away from home, the mobile node registers its care-of address to its home agent, and then the mobile node can communicate with a correspondent node. There are two modes for communications between the mobile node and a correspondent node. The first mode is bidirectional tunneling and the second mode is route optimization. The mobile node can acquire its home address or care-of address through conventional IPv6 mechanisms, such as stateless or stateful auto-configuration. The basic idea in Mobile IP is to allow a home agent to work as a stationary proxy for a mobile node. In a Mobile IPv6 network having steady home links, home agents can be configured on a DHCPv6 server, then a mobile node can acquire its home agent addresses when it requests its home address from DHCPv6 server. It also can acquire its home agent addresses when a mobile node is away from its home Ma Expires April 13, 2006 [Page 2] Internet-Draft Home Agent Configuration Option October 2005 network and requests its care-of address. To assist with rapid handovers, this document defines a new home agent option which can be used to acquire a mobile node's home agent addresses. 2. Terminology 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 RFC-2119 [1]. Throughout this document, unless otherwise specified, the acronym DHCP refers to DHCP for IPv6 (DHCPv6) as specified in RFC 3315. This document uses terminology specific to IPv6 and DHCP as defined in section "Terminology" of RFC 3315. 3. Home Agent Option The home agent option provides a list of one or more IPv6 addresses of a mobile node's home agent. The home agent addresses are listed in the order of preference for use by the mobile node. The format of the home agent option is: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OPTION_HOMEAGENT | option-len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | option-data:home-agent-address1 (IPv6 address) | | or home-address | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | option-data:home-agent-address2 (IPv6 address) | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Ma Expires April 13, 2006 [Page 3] Internet-Draft Home Agent Configuration Option October 2005 option-code: OPTION_HOME_AGENT (TBD) option-len: Length of the list of home agent addresses in octets; must be a multiple of 16 option-data: IPv6 addresses of a mobile node's home agents 4. Client behavior In a message sent by a mobile node (client) to a server, the option- len is set to 0 while the mobile node is on its home link. The option-len is set to 16 while the mobile node is away from home, and the option-data is set to the mobile node's home address. When the mobile node(client) can acquire its home address or care-of address through stateless auto-configuration, it SHOULD acquire its home agent address using stateless DHCPv6. 5. Server behavior Every home agent's address and preference are predefined on a DHCPv6 server. These home agents are classified by the link prefix, and are listed in order of preference value if there is more than one home agent on the same link. The following describes the behavior of a DHCPv6 server that implements the home agent option when the client's message includes the home agent option. If the client's option-len is 0, the link prefix is used as the key for searching home agent lists. The DHCPv6 server SHOULD create the association of the home address with its home agent addresses. If the client's option-len is 16, the home address is used as the key for searching the above-mentioned association. Ma Expires April 13, 2006 [Page 4] Internet-Draft Home Agent Configuration Option October 2005 In a message sent by a server to a mobile node (client), the option- data contains a list of IPv6 addresses which can serve as the home agent for the mobile node. Stateless DHCPv6 behavior will be specified in future. 6. Relay agent behavior A relay agent forwards messages containing the home agent option in the same way as described in section 20, "Relay Agent Behavior" of RFC 3315. 7. IANA Considerations IANA is requested to assign a DHCPv6 option code for the home agent option. 8. Security Considerations Section 23 of [RFC 3315] outlines the DHCPv6 security considerations. This option does not change the security of DHCPv6 in any significant way. 9. Acknowledgments Ma Expires April 13, 2006 [Page 5] Internet-Draft Home Agent Configuration Option October 2005 10. References 10.1. Normative References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [2] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C. and M. Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)",RFC3315,July 2003. [3] Johnson, D., Perkins, C. and J. Arkko, "Mobility Support in IPv6", RFC3775, June 2004. 10.2. Informative References [4] T. Chown, S. Venaas, A. Vijayabhaskar "Renumbering Requirements for Stateless DHCPv6", Work in Progress, May 2005 Author's Addresses Ma Yuzhi Huawei Bld., No.3 Xinxi Rd., Shang Di Information Industry Base, Hai-Dian District Beijing P.R.China Email: myz@huawei.com 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 Ma Expires April 13, 2006 [Page 6] Internet-Draft Home Agent Configuration Option October 2005 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. Ma Expires April 13, 2006 [Page 7]