Network Working Group B. Sarikaya Internet-Draft F. Xia Expires: August 20, 2008 Huawei USA February 17, 2008 Prefix Management for MIPv6 Home Link Operation over P2P Links draft-sarikaya-mext-homelink-prefix-delegation-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 August 20, 2008. Copyright Notice Copyright (C) The IETF Trust (2008). Sarikaya & Xia Expires August 20, 2008 [Page 1] Internet-Draft Prefix Delegation February 2008 Abstract In Mobile IPv6 home link operation on point-to-point links requires that one prefix can only be assigned to one mobile node by the home agent (HA) and different mobile nodes can not share this home network prefix. Managing Per-MN home network prefixes is likely to increase the processing load at the HA. Based on the idea that DHCPv6 servers can manage prefixes, we propose a new technique in which HA offloads delegation and release tasks of the prefixes to the DHCPv6 server. HA requests a prefix for an incoming mobile station to the DHCPv6 server. Based on this prefix, the mobile node can create a home address. When the mobile node leaves the network, the prefix is returned to the DHCPv6 server. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Mobile IPv6 Home Network Prefix Delegation . . . . . . . . . . 4 4. Prefix Release Procedure . . . . . . . . . . . . . . . . . . . 5 5. Miscellaneous Considerations . . . . . . . . . . . . . . . . . 6 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 7. IANA considerations . . . . . . . . . . . . . . . . . . . . . . 6 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 9.1. Normative References . . . . . . . . . . . . . . . . . . . 6 9.2. Informative References . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7 Intellectual Property and Copyright Statements . . . . . . . . . . 8 Sarikaya & Xia Expires August 20, 2008 [Page 2] Internet-Draft Prefix Delegation February 2008 1. Introduction Mobile IPv6 (MIPv6) provides client-based mobility solution to the mobile nodes (MN). In point-to-point links, home link operation should make sure to assign a unique prefix to MN. MN's home address should be configured from the home network prefix (HNP). However, in per-MN prefix model, prefix management is an issue. When an MN enters the network, its HA requests one or more prefixes for the MN for MIPv6. The prefixes should be released when the MN leaves the network. When an operator wants to renumber its network, the prefixes with different lifetime are advertised to the MN. DHCPv6 is a preferable way to manage the prefixes. AAA protocols, RADIUS or Diameter, can be involved in prefix allocation as defined in [RFC4818]. However, an AAA-based prefix delegation application is yet to be defined. In this document we propose DHCPv6 based home network prefix allocation to MIPv6 MNs. Section 3 describes Mobile IPv6 home link prefix allocation, Section 4 describes how prefixes are released and Section 5 presents miscellaneous considerations that apply. Sarikaya & Xia Expires August 20, 2008 [Page 3] Internet-Draft Prefix Delegation February 2008 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 BCP 14 [RFC2119]. This document uses the terminology defined in [RFC3315], [RFC3633]. All MIPv6 related terms are defined in [RFC3775]. 3. Mobile IPv6 Home Network Prefix Delegation Home agents (HA) MUST use per-MN home network prefixes in order to avoid multi-link subnet issues. Prefix management becomes an issue for HAs. DHCPv6 based prefix delegation can be used for this purpose as part of home link operation [I-D.devarapalli-mext-mipv6-home-link]. Mobile IPv6 per-MN prefix delegation procedure is shown in Figure 1 using DHCPv6. MN AR HA DHCPS AAA |-------|--------|--------|--------| 1. IKEv2 SA Establishment | |------->| | | 2. CFG_REQUEST | | |------->| | 3. DHCP Solicit | | |<-------| | 4. DHCP Advertise | | |------->| | 5. DHCP Request (HNP) | | |<-------| | 6. DHCP Reply (HNP) | |<-------| | | 7. CFG_REPLY (HoA) with |-------|--------|--------|--------| IKEv2 SA Establishment |<------| | | | 8. RA for CoA |------>| | | | 9. DAD NS for CoA Figure 1: Prefix request procedure 1. MN solicits security association establishment using IKEv2. 2. HA gets configuration request message [RFC4877]. 3. DHCP Client at the HA initiates DHCP Solicit procedure to request prefixes for the MN. HA creates and transmits a Solicit message as described in sections 17.1.1, "Creation of Solicit Messages" and 17.1.2, "Transmission of Solicit Messages" of RFC 3315. HA creates an IA_PD and assigns it an IAID. HA MUST include the IA_PD option in the Solicit message. 4. The DHCP server sends an Advertise message to HA in the same way as described in section 17.2.2, "Creation and transmission of Advertise messages" of RFC 3315. Sarikaya & Xia Expires August 20, 2008 [Page 4] Internet-Draft Prefix Delegation February 2008 5. HA uses the same message exchanges as described in section 18, "DHCP Client-Initiated Configuration Exchange" of RFC 3315 to obtain or update prefixes from a DHCP server. HA and the DHCP server use the IA_PD Prefix option to exchange information about prefixes in much the same way as IA Address options are used for assigned addresses. 6. HA stores the prefix information it received in the Reply message. 7. HA sends back the reply to configuration request with HoA. MN uses HoA in sending BU message to register its care of address. 8. The care of address configuration. 9. The care of address configuration. Note that home address can be assigned during the bootstrapping process and downloaded into the AR as part of the policy store. In this case, HA will be triggered by HAAA-HA protocol and HA MUST get a per-MN prefix from DHCP server using steps 3-6 in Figure 1 and MUST assign HoA from this prefix. MN can receive the bootstrapping parameters by sending DHCP Info- Request message and receiving DHCP Info-Reply message. 4. Prefix Release Procedure Prefixes can be released in two ways, prefix aging or DHCP release procedure. In the former way, a prefix SHOULD not be used by an MN when the prefix ages, and the DHCP Server can delegate it to another MN. A prefix lifetime is delivered from the DHCPv6 server to the requesting router (HA) through DHCP IA_PD Prefix option [RFC3633] and RA Prefix Information option [RFC4861]. In case of Mobile IPv6, Figure 2 can be used to release prefixes. MN HA DHCPS |------->| | 1. MN's link down | |------->| 2. DHCP Release (HNP) | |<-------| 3. DHCP Reply | | | Figure 2: MIPv6 Prefix release HA MUST release MN's home link prefix when MN returns home and goes off. The prefix release signaling is as shown in Figure 2. Site renumbering is an open issue for RADIUS/ Diameter protocols to manage prefixes. [RFC3576] MAY be used for renumbering. Sarikaya & Xia Expires August 20, 2008 [Page 5] Internet-Draft Prefix Delegation February 2008 5. Miscellaneous Considerations The considerations on how to generate IAIDs and to delegate prefixes described in [I-D.sarikaya-16ng-prefix-delegation] on the access routers (AR) apply here on the the home agents (HA). 6. Security Considerations This draft introduces no additional messages. Comparing to [RFC3633], there is no additional threats to be introduced. DHCPv6 security procedures apply. 7. IANA considerations None. 8. Acknowledgements 9. References 9.1. Normative References [I-D.devarapalli-mext-mipv6-home-link] Devarapalli, V., Kant, N., and H. Lim, "Mobile IPv6 Home Link Operation over SDO point-to-point links", draft-devarapalli-mext-mipv6-home-link-00 (work in progress), February 2008. [I-D.sarikaya-16ng-prefix-delegation] Xia, F. and B. Sarikaya, "Using DHCPv6 for Prefix Delegation in IEEE 802.16 Networks", draft-sarikaya-16ng-prefix-delegation-02 (work in progress), November 2007. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., and M. Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3315, July 2003. [RFC3576] Chiba, M., Dommety, G., Eklund, M., Mitton, D., and B. Aboba, "Dynamic Authorization Extensions to Remote Authentication Dial In User Service (RADIUS)", RFC 3576, Sarikaya & Xia Expires August 20, 2008 [Page 6] Internet-Draft Prefix Delegation February 2008 July 2003. [RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic Host Configuration Protocol (DHCP) version 6", RFC 3633, December 2003. [RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in IPv6", RFC 3775, June 2004. [RFC4818] Salowey, J. and R. Droms, "RADIUS Delegated-IPv6-Prefix Attribute", RFC 4818, April 2007. [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, September 2007. 9.2. Informative References [RFC4877] Devarapalli, V. and F. Dupont, "Mobile IPv6 Operation with IKEv2 and the Revised IPsec Architecture", RFC 4877, April 2007. Authors' Addresses Behcet Sarikaya Huawei USA 1700 Alma Dr. Suite 100 Plano, TX 75075 Email: sarikaya@ieee.org Frank Xia Huawei USA 1700 Alma Dr. Suite 100 Plano, TX 75075 Phone: +1 972-509-5599 Email: xiayangsong@huawei.com Sarikaya & Xia Expires August 20, 2008 [Page 7] Internet-Draft Prefix Delegation February 2008 Full Copyright Statement Copyright (C) The IETF Trust (2008). 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. 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