IETF Mobile IPv6 Working Group H. Jang Internet-Draft J. Cheon Expires: March 31, 2004 S. Singh SAMSUNG AIT Oct 2003 Simultaneous Registration of Multiple Care-of Addresses draft-jang-mipv6-smreg-00.txt Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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 March 31, 2004. Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved. Abstract This draft proposes a scheme that allows a mobile node to register a primary care-of address(CoA) as well as one or more non-primary CoAs by sending a single binding update message to the home agent and/or correspondent node. This is achieved by using two new mobility options defined in this draft. Mobile nodes that perform duplicate address detection procedure, such as Advance DAD and Optimistic DAD can benefit from this scheme. Proposed scheme does not require to exchange CoTI and CoT messages, usually required for the registration of each of the non-primary CoA(s). It also does not require to maintain binding management key for each of the non-primary CoA(s). Thus the proposed scheme reduces the signaling and processing Jang, et al. Expires March 31, 2004 [Page 1] Internet-Draft Simultaneous Registration of Multiple CoAs Oct 2003 overhead in Mobile IPv6 networks. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 5 4. Mobile Node Considerations . . . . . . . . . . . . . . . . . . 6 5. Home Agent Considerations . . . . . . . . . . . . . . . . . . 7 6. Correspondent Node Considerations . . . . . . . . . . . . . . 8 7. Message Formats . . . . . . . . . . . . . . . . . . . . . . . 9 7.1 Non-primary CoA Binding Request option . . . . . . . . . . . . 9 7.2 Non-primary CoA Binding Reply option . . . . . . . . . . . . . 10 8. Security Considerations . . . . . . . . . . . . . . . . . . . 12 Normative References . . . . . . . . . . . . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 13 Intellectual Property and Copyright Statements . . . . . . . . 15 Jang, et al. Expires March 31, 2004 [Page 2] Internet-Draft Simultaneous Registration of Multiple CoAs Oct 2003 1. Introduction A mobile node may have multiple interfaces to support different access technologies and current IPv6 specification allows configuration of multiple IPv6 addresses on any interface. After MN moves to foreign link, it configures new CoA using either stateless[3] or stateful mechanisms[4]. It then registers this address, termed as primary CoA, with the HA and/or CN and uses it to communicate with the CNs. According to the current Mobile IPv6 specification[2], only single CoA is used to communicate with CN in foreign network. However, it is helpful for MN to utilize multiple CoAs for more reliable connectivity, bandwidth management, delay reduction, etc. In the following environments MN MAY have one or more non-primary CoAs for any or all of the prefixes available on its current link: o MN has multiple interfaces and receives a Router Advertisement with different Prefix options from each interface in foreign network. o MN receives Router Advertisements with different prefix options on one interface. o Both of above situations. Multiple CoA Registration[5] and HA Filtering[6] are recently proposed protocols designed to utilize multiple CoAs. But some steps need to be taken to optimize the registration procedure of multiple CoAs. Before using the newly generated address, MN SHOULD perform Duplicate Address Detection procedure[3] in order to verify its uniqueness. The completion time for different CoAs may vary. So MN sends separate BU messages to HA for each of the CoAs. Most of this BU message fields are same except CoA related information. This results in signaling overhead in bandwidth constrained wireless medium. Moreover, since the return routability procedure between the MN and CN MUST be done for each of the CoAs, the situation may be more aggravated. At this point, we propose the method to register multiple CoAs, especially one or more non-primary CoAs with minimal overhead. Note that the registration for the primary CoA remains unchanged and can be done according to Mobile IPv6[2]. Jang, et al. Expires March 31, 2004 [Page 3] Internet-Draft Simultaneous Registration of Multiple CoAs Oct 2003 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 RFC2119[1]. Most of terms used in this draft are defined in [2] and the following terminology and abbreviations are used in this document. Primary Binding - The association of the home address of a mobile node with a primary CoA for that mobile node, along with the remaining lifetime of that association. Non-Primary Binding - The association of the home address of a mobile node with a non-primary CoA for that mobile node, along with the remaining lifetime of that association. Non-primary CoA Binding Request Option - The mobility option to carry the non-primary CoA and its related information necessary for the non-primary binding. This option is valid only in Binding Update messages. Non-primary CoA Binding Reply Option - The mobility option to carry the non-primary CoA and its related information necessary for the non-primary binding. This option is valid only in Binding Acknowledgement messages. Jang, et al. Expires March 31, 2004 [Page 4] Internet-Draft Simultaneous Registration of Multiple CoAs Oct 2003 3. Protocol Overview The proposed scheme operates on optimized DAD solution, hence enables the simultaneous registration for all available multiple CoAs by using single BU message. Optimized DAD solutions such as Advance DAD[7] and Optimistic DAD[8] are recently discussed in DNA BoF to minimize DAD latency and support the prompt address configuration after MN's handover. We think that with high probability it will be deployed to solve the crucial problem in Mobile IPv6, which is to minimize the handover latency. Based on optimized DAD solutions, the proposed scheme enables MN to register one or more non-primary CoAs by using new mobility options which are included in BU and BA used to register a primary CoA. After handover, MN can configure all available new CoAs through optimized DAD solution without delay and register its primary CoA to the HA and/or CNs. At that time, MN can also register additionally its one or more non-primary CoAs by using Non-primary CoA Binding Request options which will be introduced in Section 7.1. After the HA or CN receives the BU including Non-primary CoA Binding Request options, it MUST send BA including Non-primary CoA Binding Reply options to let MN know the binding status for each Non-primary CoA. The bit 'P' in Binding Cache entry is newly defined in this draft to mark if the entry is for the primary binding or non-primary binding. This scheme enables the registration of non-primary CoAs and avoids sending the duplicate information in each separate BU message without exchange of CoTI and CoT for each non-primary CoA, hence reducing the signaling and processing overheads in MIPv6. Jang, et al. Expires March 31, 2004 [Page 5] Internet-Draft Simultaneous Registration of Multiple CoAs Oct 2003 4. Mobile Node Considerations After Layer 3 handover, MN generates its New CoAs using stateless or stateful mechanisms. When CoAs are generated using stateless manner and an optimized DAD solution, all of them are available at the same time right after MN's handover, thereby it is possible for a MN to register all available CoAs at the same time. How to choose the non-primary CoAs to register among multiple available non-primary CoAs is out of scope of this draft. It may be done with help of application programs. If a MN configures only one new CoA or wants to register only one out of several available new CoAs, then it MUST register this as a primary CoA with HA according to [2]. Otherwise, it SHOULD send BU with the non-primary CoA Binding Request options for all of the non-primary CoAs that MN wants to use for the communication with the CN. Main fields of the Non-primary CoA Binding Request option, defined in section 7.1, are set as below: o Lifetime is set to the requested lifetime for the Non-primary CoA. o Non-primary CoA is set to the address which a MN wants to register to HA or CN as a non-primary CoA. This address is bound to a home address contained in Home Address option. After sending BU message with Non-primary CoA binding request option, MN MUST create new entry in its Binding Update List for each non-primary CoA. The key for searching of Binding Update List SHOULD be the destination IP address of BU and CoA. Note that all CoAs whether its primary CoA or non-primary CoA is bound to the same home address. Jang, et al. Expires March 31, 2004 [Page 6] Internet-Draft Simultaneous Registration of Multiple CoAs Oct 2003 5. Home Agent Considerations Whenever HA receives a BU, it MUST validate and authenticate it according to the steps described in Section 10.3.1 of [2]. If HA decides to accept the BU, then it MUST process the BU as follows. o HA MUST search the Binding Cache entry by using HoA in Home Address option and primary CoA in Source Address as a key, and creates or updates the corresponding Binding Cache entry according to [2]. In addition, It SHOULD set the 'P' flag to indicate the primary binding. The bit 'P' in the Binding Cache entry is newly defined to differentiate the non-primary binding and primary binding. o If the BU contains one or more Non-primary CoA Binding Request options, additional operation SHOULD be done for each non-primary CoA Binding Request option. HA MUST search the Binding Cache by using a pair of HoA in Home Address option and non-primary CoA in Non-primary CoA field in this option as a key. - If such an entry already exists in Binding Cache, HA MUST update its existing Binding Cache entry and SHOULD clear the 'P' flag to indicate non-primary binding. - Otherwise, HA MUST create Binding Cache entry for the non-primary CoA and SHOULD clear 'P' flag to indicate non-primary binding. HA SHOULD record the lifetime of non-primary CoA retrieved from the Non-primary CoA Binding Request option in Binding Cache entry. When the HA replies with BA to MN, it MUST include the Non-primary CoA Reply Binding option for each Non-primary Request Binding option to let MN know the binding status of each non-primary CoA. If HA receives packets destined to MN, it MAY forward the packets to the specific CoA based on its own predefined filtering policy[6]. How to choose the forwarding destination IP address among the multiple registered CoAs is out of scope of this draft. If there is no filtering policy, it SHOULD forward to the primary CoA by default. Jang, et al. Expires March 31, 2004 [Page 7] Internet-Draft Simultaneous Registration of Multiple CoAs Oct 2003 6. Correspondent Node Considerations When the MN registers one or more CoAs to CN, the processing procedures of the received BU in CN are the same as those in HA. The procedure of return routability remains unchanged and follows [2]. Originally, the binding management keys are maintained so as to guarantee the integrity and authenticity of the BU, and according to [2], a MN MUST perform the return routability procedure before sending every BU to CN. However, in this scheme only single BU is used to register multiple CoAs and there is no need to perform additional return routability or to maintain the binding management keys for multiple CoAs. Thus signaling overhead is reduced significantly by omitting the exchange of CoTIs and CoTs for non-primary CoAs. Jang, et al. Expires March 31, 2004 [Page 8] Internet-Draft Simultaneous Registration of Multiple CoAs Oct 2003 7. Message Formats This section introduces the new mobility options, the Non-primary CoA Binding Request option and the Non-primary CoA Binding Reply option, to support the registrations for the non-primary CoAs. 7.1 Non-primary CoA Binding Request option This is a new mobility option that MUST be included in BU messages to carry non-primary CoA, when a MN wants to register them at the same time as registering the primary CoA to a HA or CN. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type (8) | Length (8) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Lifetime (16) | Seq # (8) | Reserved (8) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Non-primary CoA (128) + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type TBA Length 8-bit unsigned integer. length fields in units of 8 octets. Lifetime 16-bit unsigned integer. The number of time units remaining before the binding for the Non-primary CoA MUST be considered expired. A value of zero indicates that the Binding Cache entry for the non-primary CoA MUST be deleted. One time unit is 4 seconds. Sequence # A 16-bit unsigned integer used to match a Non-primary CoA Binding Request option and a corresponding Non- primary CoA Binding Reply option. Jang, et al. Expires March 31, 2004 [Page 9] Internet-Draft Simultaneous Registration of Multiple CoAs Oct 2003 Reserved These fields are unused. They MUST be initialized to zero by the sender and MUST be ignored by the receiver. 7.2 Non-primary CoA Binding Reply option This is a new mobility option that MUST be included in BA messages to acknowledge binding status for non-primary CoA. This option is sent by a HA or CN in response to the receipt of the BU which includes Non-primary CoA Binding Request option. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type (8) | Length (8) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Status (8) | Seq (8) | Lifetime (16) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type TBA Length 8-bit unsigned integer. Length fields in units of 8 octets. Lifetime 16-bit unsigned integer. The number of time units remaining before the binding for the Non-primary CoA MUST be considered expired. A value of zero indicates that the Binding Cache entry for the non-primary CoA MUST be deleted. One time unit is 4 seconds. Reserved These fields are unused. They MUST be initialized to zero by the sender and MUST be ignored by the receiver. Status 8-bit unsigned integer indicating the disposition of Non-primary Binding Request option in BU. Values of the Status field less than 128 indicate that the BU was accepted by the receiving node. Values greater than or equal to 128 indicate that the Non-primary Binding Request option was rejected by the receiving node. The status values are same those defined in Section 6.1.8 of [2]. Jang, et al. Expires March 31, 2004 [Page 10] Internet-Draft Simultaneous Registration of Multiple CoAs Oct 2003 Besides, one more status is newly defined in this draft. 140 The registration for Non-primary CoA is not supported. Sequence # This is copied from Sequence # field of corresponding Non-primary CoA Binding Request option in the BU and used by the MN to match the Non-primary CoA Binding Request option and the corresponding Non-primary CoA Binding Reply option in the BA. Lifetime The granted lifetime, in time units of 4 seconds, for which the receiving node, HA or CN, SHOULD retain the entry for this MN in its Binding Cache. Jang, et al. Expires March 31, 2004 [Page 11] Internet-Draft Simultaneous Registration of Multiple CoAs Oct 2003 8. Security Considerations This draft proposes two new mobility options used for the registration of multiple CoAs. These mobility options are included within binding update message. Hence, this draft assumes that all the security considerations applied to a general Mobile IPv6 node are applied to this draft as well. Jang, et al. Expires March 31, 2004 [Page 12] Internet-Draft Simultaneous Registration of Multiple CoAs Oct 2003 Normative References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [2] Johnson, D., Perkins, C. and J. Arkko, "Mobility Support in IPv6", draft-ietf-mobileip-ipv6-24 (work in progress), July 2003. [3] Thomson, S. and T. Narten, "IPv6 Stateless Address Autoconfiguration", RFC 2462, December 1998. [4] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C. and M. Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3315, July 2003. [5] Wakikawa, R., "Multiple Care-of Addresses Registration", draft-wakikawa-mobileip-multiplecoa-02 (work in progress), September 2003. [6] Montavont, N. and T. Noel, "Home Agent Filtering for Mobile IPv6", draft-montavont-mobileip-ha-filtering-v6-00 (work in progress), July 2003. [7] Han, Y., "Advance Duplicate Address Detection", draft-han-mobileip-adad-01 (work in progress), July 2003. [8] Moore, N., "Optimistic Duplicate Address Detection", draft-moore-ipv6-optimistic-dad-03 (work in progress), September 2003. Authors' Addresses Hee-Jin Jang SAMSUNG Advanced Institute of Technology i-Networking Laboratory San 14-1, Nongseo-ri, Giheung-eup Yongin-si, Gyeonggi-do 449-712 KOREA Phone: +82 31 280 9615 EMail: heejin.jang@samsung.com URI: http://home.postech.ac.kr/~arche Jang, et al. Expires March 31, 2004 [Page 13] Internet-Draft Simultaneous Registration of Multiple CoAs Oct 2003 Jung-Hoon Cheon SAMSUNG Advanced Institute of Technology i-Networking Laboratory San 14-1, Nongseo-ri, Giheung-eup Yongin-si, Gyeonggi-do 449-712 KOREA Phone: +82 31 280 9569 EMail: jh.ch@samsung.com Shubhranshu Singh SAMSUNG Advanced Institute of Technology i-Networking Laboratory San 14-1, Nongseo-ri, Giheung-eup Yongin-si, Gyeonggi-do 449-712 KOREA Phone: +82 31 280 9552 EMail: shubhranshu@samsung.com Jang, et al. Expires March 31, 2004 [Page 14] Internet-Draft Simultaneous Registration of Multiple CoAs Oct 2003 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any intellectual property 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; neither does it represent that it has made any effort to identify any such rights. Information on the IETF's procedures with respect to rights in standards-track and standards-related documentation can be found in BCP-11. Copies of claims of rights made available for publication 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 implementors or users of this specification can be obtained from the IETF Secretariat. 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Expires March 31, 2004 [Page 15] Internet-Draft Simultaneous Registration of Multiple CoAs Oct 2003 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Acknowledgement Thank Y.Han and J.Choi who discussed together and gave the helpful advice on this draft. Jang, et al. Expires March 31, 2004 [Page 16]