Network Working Group T-W. You Internet Draft ETRI Expires: April 2006 I-D. Jang ETRI S-Y. Lee ETRI October 2005 Managements for using multiple home addresses as care-of addresses draft-you-monimi6-management-using-hoa-coa-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 April 16, 2006. Copyright Notice Copyright (C) The Internet Society (2005). Abstract This draft proposes a simple method that multiple HoAs obtained by each of heterogeneous interfaces should be registered to home agents as like CoAs to support benefits of multihoming, such as ubiquitous accessibility, redundancy, and inter interface handover. However, a You et al. Expires - april 2006 [Page 1] Using HoAs as CoAs October 2005 protocol for using HoA as CoA was already referred by [ID.Multi_PB]. In this draft, we should extend situation that HoAs are used as like CoAs, and modify registration protocol for multiple CoAs [ID.MCoA] [ID.MMI] to support reliable and robust network connectivity. Table of Contents 1. Introduction...................................................2 2. Terminology....................................................3 3. Assumptions....................................................5 4. Overview of Using HoAs as CoAs.................................5 4.1 Home Registration..........................................6 4.2 Management of Home agent' Binding Cache....................7 5. Multiple CoA Registration Extensions...........................8 5.1 Binding Cache Structure and Management.....................8 5.2 Binding Update Structure and Management....................8 5.3 Messages Format Changes....................................8 6. Operations.....................................................9 6.1 Mobile node Operations.....................................9 6.2 Home Agent Operation......................................10 6.3 Correspondent nodes.......................................11 7. Future Works..................................................11 8. Security Considerations.......................................11 9. IANA Considerations...........................................12 10. References...................................................12 10.1 Normative References.....................................12 Appendix A. Example of Scenario for using HoA registration as like CoA..............................................................12 Author's Addresses...............................................15 Intellectual Property Statement..................................17 Disclaimer of Validity...........................................17 Copyright Statement..............................................17 Acknowledgment...................................................17 1. Introduction Recently, more and more portable terminals probably have multiple interfaces to be connected to different access technologies. Each technology has its specific characteristics in terms of coverage area, bandwidth, reliability, etc. For example, the mobile node is equipped with three heterogeneous interfaces; IEEE 802.11b WLAN link, CDMA Cellular link, and 802.16 WiMAX link. These mobile nodes may be reachable through different links at the same time or use each interface alternately depending on the network environment. You et. al Expires January 2006 [Page 2] Using HoAs as CoAs October 2005 Therefore the mobile node equipped multiple interface can have benefit of the prospects of each access technology. The document [ID.Multihoming_Goals] is represented the goals and benefits of these multihomed fixed or mobile nodes, such as permanent and ubiquitous access, redundancy, and load sharing etc. However, current mobility support protocols such as Host Mobility Support in IPv6 (Mobile IPv6) [RFC 3775] and NEMO Basic Support [RFC 3963] are designed originally with single interface in mind. So these protocols do not provide methods for supporting simultaneous differentiated use of multiple access technologies. Basically a mobile node equipped multiple interfaces can have multiple Care-of addresses (CoAs) and multiple Home addresses (HoAs). For such support, we should register these addresses before everything else. The several proposals exist for that, and some of them have been implemented and tested. Multiple CoA Registration [ID.MCoA] and HA Filtering [ID.NOMADv6] are recently proposed protocols designed to register multiple CoAs used for multiple interfaces simultaneously. But some steps need to be taken to optimize the registration procedure of multiple addresses. In this document, we propose extended registration mechanism for multiple CoAs. As you know that specific situation that a Home address is handling as like Care-of address referred by [ID.Multiple_PB]. This draft should remove this restrict situation for using HoAs as CoAs. And we should support reliable accessibility and vertical handover using binding cache list in home agent through HoAs that can designate as each of interface registrations to other home agent as serving distinct interface. To achieve it, this draft proposes modified and added flag to Binding Update with mobility sub- option to provide multiple CoAs registration. 2. Terminology The following terms are introduced in the document. We defines it related to multihomed environment. You et. al Expires January 2006 [Page 3] Using HoAs as CoAs October 2005 Mobile node equipped heterogeneous interfaces Interface 2 (802.16) Interface 1 (802.11b) \|/ \|/ \|/ | | | Interface 3 (802.21) | | | |----+----| | MN | +---------+ A Mobile node may have multiple interfaces for different layer 2 technologies. Each technology has its specific characteristics in terms of coverage area, bandwidth, reliability, etc. Multiple Home agents and multiple addresses Global Home Distribution +---------+ +---------+ | HA_1 | | HA_2 | 802.16 domain +----+----+ +-+-------+ 802.11 domain | | 1:: | | 2:: | | 802.21 domain | | +---------+ +-------------------+ +-------+ | HA_3 |-----| Internet |------| CN_MR | +---------+ +--------+----------+ +-------+ 3:: | 7:: + 5:: | | | +--+--+ Interf# HoA CoA | MN | -------+----------+---------- +--+--+ 1 | 1::11EUI | x -------+----------+---------- 2 | 2::16EUI | 5::16EUI -------+----------+---------- 3 | 3::21EUI | x ----------------------------- The interfaces for different L2 technology have different home network in each of its domain. Therefore, each interface has You et. al Expires January 2006 [Page 4] Using HoAs as CoAs October 2005 only own Home agent and Home address where is distinguish situation compare with other one. 3. Assumptions A mobile node may have multiple interfaces for different L2 technologies. Thus the mobile node is multihomed situation. This multihoming that uses multiple connectivities to multiple interfaces simultaneously provides more reliable and robust network connectivity. For supporting such benefits, we propose modified home registration protocol. Exactly this protocol is extended situation for using HoA as CoA was already referred by [ID.Multiple-PB]. Before we represent proposed registration mechanism, we have some assumptions for mobile node as followings, O However the mobile node equipped with heterogeneous interfaces should have different Home addresses (HoA) per each of its interfaces. Also it may have one or more Care-of addresses (CoA) on each of its interfaces. O The mobile node SHOULD know to what is the interface to be allocated for the mobile node's CoAs or HoAs. O Consequently, the situations that happen in each of its interfaces could be managed independently by the mobile node. In other words, if a mobile node was connected to foreign network using specific interface while move to foreign network, a Care-of address is allocated to appropriate interface. Then the mobile node can register this CoA to a Home agent that is located in relevant interface's home network. 4. Overview of Using HoAs as CoAs When a mobile node has heterogeneous interfaces, it gets several IPv6 global addresses as serving Home addresses or as Care-of addresses on distinct interface. In this situation, we propose modified home registration process that multiple HoAs allocated per each interface should be registered as like to CoAs’ one to support benefits of multihomed mobile node, such as ubiquitous accessibility, redundancy, and load balancing. However, a protocol for multiple CoA Registration [ID.MCoA] was proposed to utilize multiple CoAs and to support benefits of multihomed mobile node. At this point, we would modify and added some mechanism to these protocols to support redundancy, robust network connectivity, and load sharing. You et. al Expires January 2006 [Page 5] Using HoAs as CoAs October 2005 4.1 Home Registration As you know that the home registration is process that is registration between the mobile node and its home agent, authorized by the use of IPsec. In cases for mobile node equipped with multiple interfaces, if the mobile node wants to register multiple bindings to its home agent, it MUST generate a Binding Unique Identifier (BID) for the primary care-of address and record it into the binding update list entry [ID.MCoA]. In this draft, we have some assumption that a mobile node equipped with heterogeneous interfaces should have different HoAs per each of its interfaces. For home registration, we should use multiple HoAs allocated in distinct interface as CoAs. If the mobile node obtains multiple home addresses, it must register HoAs allocated in each interface to appropriated interfaces’ serving Home agent. However, using HoA as CoA was referred by [ID.Multi_PB]. For instance, a MN has two HoAs (HoA1 and HoA2) on two distinct home links. MN is connected to these two home links via two interfaces. If the MN looses its connectivity on its first interface, HoA1 is not reachable. It may then want to register HoA2 as a CoA for HoA1 in order to keep receiving packets intended to HoA1, via the second interface. As mentioned above, while an mobile node equipped two interfaces is located in home link by one interface, the mobile node operate as like to situation that the mobile node moves to foreign network. In this specific environment, HoAs are used as like to CoA. In this draft, we remove this restrict situation for using HoAs as CoAs. At first we modified and added flag to Binding Update with mobility sub-option to provide multiple CoAs registration. Because we have to discriminate between HoA registration and CoA registration. The mobile node should register all of HoAs acquired from own interfaces to all of Home agents except own Home agent. With this registered HoA can be used as like CoA that represent the mobile node's present position. But registered HoA should transfer a flow that is toward to the mobile node to another home agent. Therefore we can support ubiquitous accessibility using HoA registration as like CoA. That is to say that we use multiple interfaces simultaneously. For instance, at first a Home agent has to intercept the flow toward to a mobile node, and then the home agent try to find a CoA that combined the mobile node's HoA and CoA. If the home agent do not find it, should transfer the flow to other home agent through registered HoA in binding chache lists. As a result, we do change interface, You et. al Expires January 2006 [Page 6] Using HoAs as CoAs October 2005 which is served for present flow because each of home agents can be distinct by difference interfaces. 4.2 Management of Home agent's Binding Cache As mentioned before, we also assumed that a mobile node should know to what is the interface to be allocated for the mobile node's CoAs or HoAs. Therefore, the mobile node can manage and register multiple addresses that allocated to each interface independently. When the mobile node boots up, we assume that multiple HoAs is allocated to each of its interface. And then the mobile node registers multiple HoAs to Home agents using Binding Update with BID sub-options as like to Multiple CoA registration [ID.MCoA] with additional flag. As a result, a HoA is binding to different HoAs that allocated from other serving home networks to relevant interfaces For example, a mobile node has three heterogeneous interfaces, and three HoAs that allocated by each of its interfaces; HoA1, HoA2, and HoA3. The mobile node registers three HoAs to each of own home agents as like to CoA registration. After this home registration ended, we could see the each of Home agents’ binding cache as followings; Binding Cache in Home agent 1 (HoA1): [home address = HoA1, care-of address = HoA2, BID 1, H flag = 1 …] [home address = HoA1, care-of address = HoA3, BID 2, H flag = 1 …] In this protocol, the binding lists using HoAs as CoAs should keep continuously till can not use the HoA cause to occurred failure of specific interface. If the mobile node's one interface should be attached to home network, this binding list could be disabled, not to remove it. After HoAs were registered, if the mobile node moves to foreign network, it should obtain CoA (CoA1) by interface 2 attached to foreign network. This CoA also registered specific Home agent that the provide packet delivery service to relevant interface obtained the CoA. Therefore, the binding cache has three binding lists. A head of the two binding lists are registered using HoA as CoA, last one is actually CoA represented current locator registration. Binding Cache in Home agent 2 (HoA2): [home address = HoA2, care-of address = HoA1, BID 1, H flag = 1 …] [home address = HoA2, care-of address = HoA3, BID 2, H flag = 1 …] [home address = HoA2, care-of address = CoA1, BID 3 H flag = 0 …] This procedure is achieved as like to refer in Multiple CoA registration [ID.MCoA]. That is, this interface attached to foreign network sets primary, this list should be used preferentially. You et. al Expires January 2006 [Page 7] Using HoAs as CoAs October 2005 5. Multiple CoA Registration Extensions In this section are described the changed to allow registration multiple CoAs to manage registration HoA as like CoA distinguish between HoA and CoA registration. 5.1 Binding Cache Structure and Management Additional items are required in the binding cache structure, which are: - H flag of the binding cache entry. The H flag is represented by the mobile node whether this registration is for HoA or not by means of Binding Update sub-option as like [ID.MCoA]. The value MUST be set if the Binding Update is case of HoA registration. 5.2 Binding Update Structure and Management Additional items are required for the binding update structure, which are: - H flag: MUST be included whenever the mobile node registers HoA as like CoA. 5.3 Messages Format Changes - Binding Unique Identifier sub-option included H flag The Binding Unique Identifier sub-option is included in Binding Update, Binding Acknowledgment, Binding Refresh Request, and Binding Error if needed. We have to include H flag in BID sub- option to distinct between HoA and CoA home registration. 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 = TBD | Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Binding Unique ID (BID) |P|H| Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-------------------------------+ Type Type value for Binding Unique Identifier will be assigned later. Length The value MUST be always 4. Binding Unique ID (BID) The BID which is assigned to the binding carried in You et. al Expires January 2006 [Page 8] Using HoAs as CoAs October 2005 the Binding Update with this sub-option. BID is 16-bit unsigned integer. A value of zero is reserved. Flag Stop Proxy Neighbor Advertisement (P) Flag This flag is checked only when a Binding Update is for de-registration and the destination of a Binding Update is mobile node's home agent.Otherwise, this flag MUST be ignored Flag Notify HoA registration (H) Flag This flag represents whether this registration is for HoA registration or not. When the flag set, this binding is for HoA registration. If Binding Update does not contain a BID, this flag does not necessary to check. 6. Operations In this section are described the operations for mobile node and home agent. Correspondent node (CN)'s operation is not changed. 6.1 Mobile node Operations For using multiple HoAs as CoAs, a mobile node equipped multiple interfaces achieves operations as following fields: O A mobile node may have multiple interfaces for different L2 technologies. O Each interface should be different Home addresses. So multiple home agents are placed globally despite routing domains. And multiple home agents serving a different home network are distributed to different routing domain. O A mobile node registers home address to own home agent. O A mobile node should sending Binding Update with BID sub-option included H filed set to home registration. O When a mobile node moves to foreign network, it can acquire CoA through interface attached to foreign network. The mobile node registers CoA sending Binding Update with BID sub-option contained H flag be unset to own home agents. O This Registration process is like to Multiple CoA registration one. The Binding Update message with BID sub-option includes H flag be unset means that this binding list should be used preferentially. You et. al Expires January 2006 [Page 9] Using HoAs as CoAs October 2005 6.2 Home Agent Operation To achieve using HoAs as CoAs, a home agent should change binding cache and some operation. O Multiple home agents are distributed globally routing domains. O Basically a home agents only manages own home address allocated by using own network prefix. However for activating multiple home agents, Binding cache in all of home agents must be synchronized. The [ID.HAHA] protocol was already proposed for management of Home agents list and Inter home agent signaling. We describe this problem in chapter 7. O But if one home agent is occurred failure not a interface, the specific binding information that is listed in its home network does not use. Therefore for future works, we can propose synchronization method between multiple home agents for supporting home agent redundancy. O If home agent received the Binding Update, it must then create a new entry in its Binding cache entry. If Binding Update with BID sub-option included H filed be set is received, it make new entry with check H filed set 1. It means that this binding list's address is mobile node's HoA. O A home agent can intercept packet toward to mobile nodes. And this packet is send to the mobile node using tunneling. O If a home agent receives de-registration message when the specific interface is connected to own network directly, it remove specific binding cache lists that H flag is unset. And the other lists represent H flag be set should be disabled till the primary interface is disconnected. O while a mobile node is serving as the home agent for mobile node it must attempt to intercept packets on the mobile node's home link that are addressed to mobile node. Then home agent sends packets to the mobile node by tunneling. O Suddenly the interface, which is activated for current session, occur failure. At first the home agent must find another binding list bound to the mobile node's home address represented H flag be unset. O If the home agent do not find another list contains H flag be unset while do not response from the mobile node's interface. It should use binding list represented flag be set for the first time. You et. al Expires January 2006 [Page 10] Using HoAs as CoAs October 2005 O The current packets are sending to other home agent that is represented by binding list bound to mobile node's HoA. Specific operation procedure is explained later in appendix section. 6.3 Correspondent nodes The rule for maintaining a Binding Cache is the same for home agents. However, we modify Home agents’ one. Therefore management of binding cache is not equal, but correspondent node should operate as like to original Mobile IPv6. 7. Future Works As mentioned above, using multiple HoA as CoA have some drawback. One is not to support redundancy for distributed multiple home agents’ failure. For management of Home agents list, Inter home agent management protocol was proposed [ID.HAHA]. In [ID.HAHA] protocol, multiple home agents for one mobile node can be synchronized about its binding cache. For supporting redundancy of home agent, we can propose synchronization method between multiple home agents for one mobile node with multiple interfaces. Easily approach; Inter Home agent management protocol [ID.HAHA] is possible to one of those solutions. Other approach is possible to passive propagate binding cache lists. As like that, to synchronize multiple home agents, specific methods are leaved for future works. Other critical consideration item is endless loop request for changing serving home agent by circularly reference. If home agent 1 were requested for changing serving home agent to home agent 2, the home agent 2 would possible to request change to home agent 1 again. In this case, there is request loop by the circularly reference. One possible approach to avoid this loop restricts changing request to one time. For instance, in above same situation, home agent 2 that receives change request from home agent 1 does not try to change other serving home agent. For such support, we can add one option on packet that is sent to mobile node from home agent to check count of request changing. 8. Security Considerations This document has no direct impact on Internet infrastructure security. You et. al Expires January 2006 [Page 11] Using HoAs as CoAs October 2005 9. IANA Considerations This document has no IANA considerations. 10. References 10.1 Normative References [ID.Multi_PB] N. Montavont, R. Wakikawa, T. Ernst, C. Ng, K. Kuladinithi, "Analysis of Multihoming in Mobile IPv6," draft-montavont-mobileip-multihoming-pb-statement- 04.txt” February 2005. [ID.MCoA] Ryuji Wakikawa, Thierry Ernst, Kenichi Nagami, "Multiple Care-of Addresses Registration," draft-wakikawa-mobileip- multiplecoa-04.txt June 2005 [ID.MMI] N. Montavont, T. Noel, M. Kassi-Lahlou, "Mobile IPv6 for multiple interfaces (MMI)," draft-montavont-mip6-mmi-02.txt, July 2005 [ID.Multihoming_Goals] T. Ernst, N. Montavont, R. Wakikawa, E. Paik, C. Ng, K. Kuladinithi, T. Noel, July, 2004. [RFC 3775] D. Johnson, C. Perkins, and J. Arkko. "Mobility support in IPv6," Request for Comments (Standards Track) 3775, IETF, June 2004. [RFC 3964] V. Devaraplli, R. Wakikawa, A. Petrescu, and P. Thubert "Network Mobility (NEMO) Basic Support Protocol," Request for Comments (Standards Track) 3963, IETF, January 2005 [ID.HAHA] Ryuji Wakikawa, Vijay Devarapalli, Pascal Thubert, "Inter Home Agents Protocol (HAHA)," draft-wakikawa-mip6-nemo- haha-01.txt, February 2004. [ID.NOMADv6] K. Kuladinithi, N. A. Fikouras, C. Goerg, ComNets-ikom, "Filters for Mobile IPv6 Bindings (NOMADv6)," draft- nomadv6-mobileip-filters-02.txt, May Appendix A. Example of Scenario for using HoA registration as like CoA This section tries to illustrate the multihoming scenario for using HoA registration as like CoA. The mobile node has three heterogeneous interfaces; 802.11b, 802.11, and 802.21. and three HoAs that allocated by each of its interfaces as depicts Figure 1. The mobile You et. al Expires January 2006 [Page 12] Using HoAs as CoAs October 2005 node registers three HoAs to each of own home agents as like to CoA registration. After HoAs were registered, when the mobile node moves to foreign network as represent 5:: for IPv6 prefix, it should obtain CoA (5::16EUI) through interface 2 (802.16) attached to foreign network directly. This CoA also registered specific Home agent (Home agent 2). The Figure 1 depicts each of Home agents’ Binding cache database and current network situation. +---------+ +---------+ 802.11 domain | HA_1 | | HA_2 | 802.16 domain +----+----+ +-+-------+ | | 1:: | | 2:: | | 802.21 domain | | +---------+ +-------------------+ +-------+ | HA_3 |-----| Internet |------| CN_MR | +---------+ +--------+----------+ +-------+ 3:: | 7:: + 5:: | | | +--+--+ Interf# HoA CoA | MN | -------+----------+---------- +--+--+ 1 | 1::11EUI | x -------+----------+---------- 2 | 2::16EUI | 5::16EUI -------+----------+---------- 3 | 3::21EUI | x -------+----------+---------- Binding Cache Database: Binding Cache in Home agent 1 (HoA1): [HoA = 1::11EUI, CoA = 2::16EUI, BID 1, H flag = 1 …] [HoA = 1::11EUI, CoA = 3::21EUI, BID 2, H flag = 1 …] Binding Cache in Home agent 2 (HoA2): [HoA = 2::16EUI, CoA = 1::11EUI, BID 1, H flag = 1 …] [HoA = 2::16EUI, CoA = 3::21EUI, BID 2, H flag = 1 …] [HoA = 2::16EUI, CoA = 5::16EUI, BID 3, H flag = 0 …] Binding Cache in Home agent 3 (HoA3): [HoA = 3::21EUI, CoA = 1::11EUI, BID 1, H flag = 1 …] [HoA = 2::21EUI, CoA = 2::16EUI, BID 2, H flag = 1 …] Figure 1: The mobile node equipped different interfaces has multiple home agents. And represent situation attached to foreign network through 802.16 interface. You et. al Expires January 2006 [Page 13] Using HoAs as CoAs October 2005 When the correspondent node (CN), which is attached to IPv6 network represented 7:: for IPv6 prefix, tries to communicate with the mobile node, it should obtain the mobile node's home address using DNS query. If the correspondent node obtain 1::11EUI for mobile node's home address, it send initiate packet to the mobile node using 1:11EUI for mobile node's home address. After the home agent 1 intercepts this packet, and then it should first find appropriate binding list contained a CoA among binding lists whose H flag is unset. Although the home agent 1 tries to find that, but there is not binding list as represented H flag is unset as depicts Figure 1. Next it should use binding list represented H flag is set to find appropriate address toward to mobile node. In Figure 1's Binding Cache Database, the home agent 1 tries to send initiate packet to address 2::16EUI using BID 1's binding list though bi-directional tunneling. The home agent 2, which receive packet toward to 2::16EUI for mobile node's home address, also intercept this packet. In this case, the home agent 2 can find binding list as represented BID 3 among binding lists whose H flag is unset. And then the home agent 2 tries to send this packet to 5::EUI21 again through re-establishment tunneling. Therefore, with this registered HoA can be used as like CoA, it can support ubiquitous accessibility. That is to say that we use multiple interfaces simultaneously. Figure 2 shows how to use registered HoA in binding lists to supporting ubiquitous accessibility. You et. al Expires January 2006 [Page 14] Using HoAs as CoAs October 2005 +---------+ +---------+ 802.11 domain | HA_1 |=====| HA_2 | 802.16 domain +----+----+ +---+-----+ | = | 1:: | = | 2:: | = | 802.21 domain | = | +---------+ +----------------=-++ +-------+ | HA_3 |-----| Internet = |------| CN_MR | +---------+ +--------+----=-----+ +-------+ 3:: | = 7:: + = 5:: | |= | +--+=-+ Interf# HoA CoA | MN | -------+----------+---------- +--+--+ 1 | 1::11EUI | x -------+----------+---------- === Bidirectional Tunnel 2 | 2::16EUI | 5::16EUI -------+----------+---------- 3 | 3::21EUI | x -------+----------+---------- Figure 2: The Correspondent node tries to communicate with mobile node using 1::11EUI for mobile node's home address. This Figure represents a method of communication using two of bi-directional tunneling through HoA registration in binding lists Author's Addresses Taewan You ETRI/PEC 161 Gajeong-Dong, Yuseong-Gu, Daejeon 305-350, Korea Tel : +82 42 860 4996 Fax : +82 42 861 5404 E-mail : twyou@pec.etri.re.kr Indong Jang ETRI/PEC 161 Gajeong-Dong, Yuseong-Gu, Daejeon 305-350, Korea Tel : +82 42 860 4978 Fax : +82 42 861 5404 E-mail : indoi@pec.etri.re.kr Seungyun Lee ETRI/PEC You et. al Expires January 2006 [Page 15] Using HoAs as CoAs October 2005 161 Gajeong-Dong, Yuseong-Gu, Daejeon 305-350, Korea Tel : +82 42 860 5508 Fax : +82 42 861 5404 E-mail : syl@etri.re.kr You et. al Expires January 2006 [Page 16] Using HoAs as CoAs October 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. You et. al Expires January 2006 [Page 17]