MIPSHOP Working Group Heejin Jang Internet-Draft Samsung AIT Expires: August 31, 2006 Junghoon Jee ETRI Youn-Hee Han Samsung AIT Soohong Daniel Park Samsung Electronics Jaesun Cha ETRI February 27, 2006 Mobile IPv6 Fast Handovers over IEEE 802.16e Networks draft-jang-mipshop-fh80216e-02.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 31, 2006. Copyright Notice Copyright (C) The Internet Society (2006). Abstract This document describes how a Mobile IPv6 Fast Handover could be Jang, et al. Expires August 31, 2006 [Page 1] Internet-Draft FMIPv6 over 802.16e February 2006 implemented on link layers conforming to the 802.16e suite of specifications. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Deployment Architectures for Mobility on IEEE 802.16e . . . . 6 4. IEEE 802.16e Handovers Overview . . . . . . . . . . . . . . . 8 5. Network Topology Acquisition and Cell Selection . . . . . . . 9 6. Interaction between FMIPv6 and IEEE 802.16e . . . . . . . . . 10 6.1. Access Router Discovery . . . . . . . . . . . . . . . . . 10 6.2. Handover Preparation . . . . . . . . . . . . . . . . . . . 10 6.3. Handover Execution . . . . . . . . . . . . . . . . . . . . 11 6.4. Handover Completion . . . . . . . . . . . . . . . . . . . 11 7. The Examples of Handover Scenario . . . . . . . . . . . . . . 12 7.1. Predictive Mode . . . . . . . . . . . . . . . . . . . . . 12 7.2. Reactive Mode . . . . . . . . . . . . . . . . . . . . . . 13 8. Security Considerations . . . . . . . . . . . . . . . . . . . 16 9. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . . 17 10. Normative References . . . . . . . . . . . . . . . . . . . . . 17 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18 Intellectual Property and Copyright Statements . . . . . . . . . . 19 Jang, et al. Expires August 31, 2006 [Page 2] Internet-Draft FMIPv6 over 802.16e February 2006 1. Introduction In order to provide the session continuity during handover, Mobile IPv6 protocol [2] is currently available. It is capable of handling IP handovers between different subnets in a transparent way for higher-level connections. However, the handover latency resulting from standard Mobile IPv6 is often unacceptable to real-time traffic such as Voice over IP, and Mobile IPv6 Fast Handover protocol (FMIPv6) [3] has been proposed as a mechanism to improve the handover latency by predicting and preparing the impending handover in advance. As [4] pointed out, Mobile IPv6 Fast Handover assumes the support from the link-layer technology, but the particular link-layer information available, as well as the timing of its availability (before, during or after a handover has occurred), differs according to the particular link-layer technology in use. This document describes Mobile IPv6 Fast Handovers on 802.16 networks. There are three kinds of handover modes, hard handover, fast BS switching and soft handover in IEEE 802.16e. In this version of the draft, we consider the hard handover mode because this is the default mode. We begin with a summary of a handover procedure on 802.16e [6], the amendment of 802.16 for mobility. Then the interaction between 802.16e and FMIPv6 is presented with the primitives proposed by IEEE 802.21 for the close interaction between Layer 2 and Layer 3. Lastly, the examples of handover scenario are described for both predictive mode and reactive mode. Jang, et al. Expires August 31, 2006 [Page 3] Internet-Draft FMIPv6 over 802.16e February 2006 2. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document is to be interpreted as described in RFC2119 [1]. Most of terms used in this draft are defined in Mobile IPv6 [2] and FMIPv6 [3]. The following terms come from IEEE 802.16e specification [6]. MOB_NBR-ADV IEEE 802.16e neighbor advertisement message sent periodically by a base station. MOB_MSHO-REQ IEEE 802.16e handover request message sent by a mobile node. MOB_BSHO-RSP IEEE 802.16e handover response message sent by a base station. MOB_BSHO-REQ IEEE 802.16e handover request message sent by a base station. MOB_HO-IND IEEE 802.16e handover indication message sent by a mobile node. BSID IEEE 802.16e base station identifier. Additionally, the following triggers are proposed by IEEE 802.21 [7] and the standardization is in progress. We also referred to [5]. New_BS_Found (NBF) A trigger from the link layer to IP layer in a mobile node to report that new BS is detected. Link_Going_Down (LGD) Jang, et al. Expires August 31, 2006 [Page 4] Internet-Draft FMIPv6 over 802.16e February 2006 A trigger from the link layer to IP layer in a mobile node to report that a link down event will be fired in the near future. Link_Up (LUP) A trigger from the link layer to IP layer in a mobile node to report that the mobile node completes L2 connection establishment with a new BS. Link_Switch (LSW) A control command come from IP layer to the link layer in a mobile node in order to force to switch to new BS. Jang, et al. Expires August 31, 2006 [Page 5] Internet-Draft FMIPv6 over 802.16e February 2006 3. Deployment Architectures for Mobility on IEEE 802.16e In this section, we describe two possible deployment architectures of 802.16 networks and the mobile node's handover over it. Figure 1 shows the deployment with two IP subnets. An access router (AR) and several base stations (BSs) form a single subnet. In this case, the movement between BSs does not always require IP mobility. The handover from BS1 to BS2, or within same subnet, can be carried out using link layer mobility without IP mobility. However, the handover from BS5 to BS6 may require IP mobility since they belong to the different subnets respectively. /-------------------------------------\ | IP Backbone | \-------------------------------------/ | | /-----------\ /-----------\ | AR1 | | AR2 | \-----------/ \-----------/ / / | \ \ / / | \ \ / / | \ \ / / | \ \ / | | | \ / | | | \ BS1 BS2 BS3 BS4 BS5 BS6 BS7 BS8 BS9 BS10 Figure 1. The 802.16e deployment architecture in a centralized manner Figure 2 represents an alternative 802.16e deployment where a subnet consists of only single AR and single BS. In this case, a BS may be integrated with an AR, composing one box in view of implementation. Every handover in this architecture means a change of subnet, resulting in IP handovers. /------------------\ | IP Backbone | \------------------/ / | \ / | \ / | \ ----- ----- ----- | AR1 | | AR2 | | AR3 | | BS1 | | BS2 | | BS3 | ----- ----- ----- Figure 2. The 802.16e deployment architecture with the integrated BS & AR Jang, et al. Expires August 31, 2006 [Page 6] Internet-Draft FMIPv6 over 802.16e February 2006 The FMIPv6 is a kind of IP mobility solution, so needs to be performed when a mobile node (MN) handovers across the subnet. Regarding its specific operation, the FBU (Fast Binding Update) message is sent conditionally depending on whether the target BS is under different subnet or not. The information may be available to the MN before handover through the link-layer technology or implementation-specific method. This document describes the case when an MN handovers across the subnet. Jang, et al. Expires August 31, 2006 [Page 7] Internet-Draft FMIPv6 over 802.16e February 2006 4. IEEE 802.16e Handovers Overview Compared with the handover in the wireless LAN, the 802.16e handover mechanism consists of more steps since 802.16e embraces the functionality for elaborate parameter adjustments and procedural flexibility. When an MN stays in a link, it listens to L2 neighbor advertisement message, named MOB_NBR-ADV, from its serving BS. A BS broadcasts it periodically to identify the network and announces the characteristics of neighbor BSs. Once the MN receives this, it decodes this message to find out information about the parameters of neighbors for its future handover. With the provided information in this message, the MN may minimize the handover latency by decoding the channel number of neighbors and reducing the scanning time, or may select the target BS tailored for its taste. In 802.16e, the handover procedure is conceptually divided into two steps: ``handover preparation'' and ``handover execution'' [8]. The handover preparation begins with a decision of MN or BS. During the handover preparation, neighbors are compared by the metrics such as signal strength or QoS parameters and the target BS is selected among them. If necessary, the MN may try to associate (initial ranging) with candidate BSs to expedite a potential future handover. Once the MN decides handover, it may notify its intent by sending MOB_MSHO-REQ message to the serving BS (s-BS). The serving BS then replies with MOB_BSHO-RSP containing the recommended BSs to the MN after negotiating with candidates. When the target is decided, the BS may confirm the handover to target BS (t-BS) over backbone. The BS also can trigger handover with MOB_BSHO-REQ message. After handover preparation, handover execution occurs. When the MN sets the target BS finally and is about to move to the link, it sends MOB_HO-IND to the serving BS as a final indication for handover and for resource release for it, then conducting handover. Once the MN switches the link, it shall conduct 802.16e ranging through which it can acquire physical parameters from the target BS, tuning its parameters to the target BS. After ranging with the target BS successfully, the MN negotiates basic capabilities and performs authentication, finally registering with the target BS. If the target BS has already learned some contexts such as authentication or capability parameters through backbone, the MN may omit the corresponding procedures. Since this point, the target BS starts to serve the MN and communication via target BS is available. However, when the MN moves to different subnet, it should re-configure new IP address and re-establish IP connection. To resume the active session of previous link, the MN should perform IP handover additionally. Jang, et al. Expires August 31, 2006 [Page 8] Internet-Draft FMIPv6 over 802.16e February 2006 5. Network Topology Acquisition and Cell Selection An MN can learn the network topology and acquire the link information in two ways. One method is via L2 neighbor advertisement. A BS supporting mobile functionality shall broadcast MOB_NBR-ADV message including the network topology at a periodic interval (maximum interval, 1sec.). This message includes the BSID and channel information of neighbor BSs and is used to facilitate the MN's synchronization with neighbor BSs. An MN can collect the necessary information of the neighbor BSs for its future handover through this message. Another method for acquisition of network topology is scanning, which is the process to seek and monitor available BS suitability as targets for handover. While the MOB_NBR-ADV message includes static information about neighbor BSs, scanning provides rather dynamic parameters such as link quality parameters. Since the MOB_NBR-ADV message delivers a list of neighbor BSIDs periodically and scanning provides a way to sort out some adequate BSs, it is recommended that when new BSs are found in the advertisement, the MN identifies them via scanning and resolves their BSIDs to the associated network information. The association, optional initial ranging procedure occurring during scanning, is one of the helpful method to facilitate the impending handover. An MN is able to get ranging parameters and service availability information for the purpose of proper selection of the target BS and expediting a potential future handover to it. After learning about neighbors, the MN may compare them to find another BS which can serve better than the serving BS. The target BS may be determined considering various criteria such as required QoS, cost, user preference, policy, etc. How to select the target BS is not in the scope of this draft. Jang, et al. Expires August 31, 2006 [Page 9] Internet-Draft FMIPv6 over 802.16e February 2006 6. Interaction between FMIPv6 and IEEE 802.16e In this section, we describe the desirable FMIPv6 handover procedure in 802.16 networks. We introduce four primitives for the close interaction between FMIPv6 and 802.16e, and the interaction is presented with them. 6.1. Access Router Discovery Once a new BS is detected through the reception of MOB_NBR-ADV, an MN tries to learn the associated AR information. This procedure is called AR discovery. With new BSID in MOB_NBR-ADV message, the MN requests the associated AR information to the PAR (Previous AR). To minimize the possible latency from new BS detection in link layer (802.16) to the resolution in IP layer (fmip6), the link layer can trigger the New_BS_Found primitive to the IP layer within the MN. The result of resolving BSIDs is a list of [BSID, AR-Info] tuples. AR-Info consists of the corresponding new AR's information including its prefix, IP address and link layer address. The RtSolPr (Router Solicitation for Proxy Advertisement) and PrRtAdv (Proxy Router Advertisement) messages of FMIPv6 are used for the resolution. Note that the AR discovery procedure is not necessarily involved with any specific handover procedure and the MN may perform them at any convenient time. 6.2. Handover Preparation As mentioned in Section 4, an MN may initiate handover by sending MOB_MSHO-REQ to the serving BS and receive MOB_BSHO-RSP from it. Also, the BS can initiate handover by sending MOB_BSHO-REQ to the MN. After receiving either MOB_BSHO-RSP or MOB_BSHO-REQ message, the MN may send FBU (Fast Binding Update) to the PAR. At this time, the Link_Going_Down (LGD) is introduced to signal IP layer of the arrival of MOB_BSHO-REQ/MOB_BSHO-RSP in link layer as soon as possible. The MN may be notified of the target BS as a parameter at the same time. On receiving LGD, the MN's IP layer (fmip6) sends FBU to the PAR. Before sending FBAck (Fast Binding Acknowledgement) to the MN, the PAR sets up tunnel between PCoA (Previous CoA) and NCoA (New CoA) by exchange of HI (Handover Initiate) and HAck (Handover Acknowledge) messages, and forwards the packets destined for MN to NCoA. During this time, an available NCoA is confirmed with HAck message. After the MN sends a MOB_HO-IND to the serving BS, any packet data transfer between MN and serving BS is not allowed any more even though the resource retain timer does not expire in serving BS. Therefore, if possible, the MN should exchange a FBU and a FBAck message with the PAR before sending MOB_HO-IND to the serving BS so Jang, et al. Expires August 31, 2006 [Page 10] Internet-Draft FMIPv6 over 802.16e February 2006 as to operate as predictive mode. 6.3. Handover Execution When the FBAck message arrives before handover, the MN runs predictive mode. If the MN can not acquire FBAck message on the current link, it should run reactive mode after handover. Note that when MOB_HO-IND is sent prior to the arrival of FBAck, the MN should operate as reactive mode since when the serving BS receives this message, it releases MN's all connections and resources. The serving BS may retain the resource until the resource retain timer expires. If applicable, the primitive from IP layer to link layer can be used to optimize the L2/L3 interaction. Link_Switch trigger (LSW) can be issued from the IP layer to link layer within MN when FBAck message arrives to make the possibility of predictive mode operation higher or to promote the issue of MOB_HO-IND message immediately. Similar concept has already introduced for the wireless LAN in [5] and IEEE 802.21 document [8] also provides MIH (Media Independent Handover) command service for the same reason. After switching links, the MN synchronizes with the target BS and performs the 802.16e network entry procedure. The MN may exchange the RNG-REQ/RSP, SBC-REQ/RSP, PKM-REQ/RSP and REG-REQ/RSP messages with the target BS. Some of these messages may be omitted if the (previously) serving BS transferred the context to the target BS over the backbone before. As soon as completing the network entry, the MN's link layer informs its IP layer of the fact with Link_Up (LUP) trigger, forcing IP layer to send FNA (Fast Neighbor Advertisement) to the NAR (New AR). In case of reactive mode, the MN should include the FBU within the FNA message. 6.4. Handover Completion Receiving the FNA, in predictive mode, the NAR should verify the availability of NCoA. If the NAR detects the NCoA is already in use, it MUST discard the FBU and reply with Router Advertisement with Neighbor Advertisement Acknowledge (NAACK) option to the MN. Otherwise, the NAR starts to flush the buffered packets to MN. In reactive mode, the NAR should forward the inner FBU to the PAR, establishing the tunnel, finally forwarding the packets destined to the NCoA to the MN. Jang, et al. Expires August 31, 2006 [Page 11] Internet-Draft FMIPv6 over 802.16e February 2006 7. The Examples of Handover Scenario In this section, the recommended handover procedure over 802.16 network is shown for both predictive mode and reactive mode. Note that there is no need of IP mobility when the target BS is under same subnet. Therefore FBU is sent conditionally depending on whether the target BS is under different subnet or not. In following scenarios, the MN is assumed to move to different subnet. 7.1. Predictive Mode The procedure is described briefly as follows. 1. A BS broadcasts MOB_NBR-ADV periodically. 2. If the MN discovers a new neighbor BS in this message, it may perform scanning for it. 3. When a new BS is found through the MOB_NBR-ADV or scanning, the MN's link layer notifies it of the IP layer (fmip6) by New_BS_Found primitive. 4. Then the MN may try to resolve new neighbor's BSID to the associated AR by exchange of RtSolPr and PrRtAdv with the PAR. 5. The MN initiates handover by sending MOB_MSHO-REQ to the serving BS and receives MOB_BSHO-RSP from it. Also, the serving BS can initiate handover by sending MOB_BSHO-REQ to the MN. 6. When the MN receives either MOB_BSHO-RSP or MOB_BSHO-REQ from BS, its link layer triggers Link_Going_Down to IP layer. 7. On reception of LGD, the MN IP layer exchanges FBU and FBAck with the PAR. Before sending the FBAck, the PAR establishes tunnel with the NAR by exchange of HI and HAck messages. During this time, the NAR confirms NCoA availability in new link via HAck. 8. When the FBAck arrives before handover, the MN operates as predictive mode. It sends MOB_HO-IND as a final indication of handovers. Jang, et al. Expires August 31, 2006 [Page 12] Internet-Draft FMIPv6 over 802.16e February 2006 9. The MN conducts handover to the target BS and performs 802.16e network entry procedure. 10. When the network entry is completed, the MN's link layer signals its IP layer with Link_Up and then the MN issues FNA to the NAR. 11. When the NAR receives the FNA from the MN, it delivers the buffered packets to the MN. ---------- ---------- MN L3 MN L2 | s-BS PAR | | NAR t-BS | ---------- ---------- | | | | | | |<-NBF-|<-----MOB_NBR-ADV-------| | | | | |( Scanning )| | | | |--------------(RtSolPr)-------------->| | | |<--------------PrRtAdv----------------| | | | | | | | | | | [MN initiation] | | | | | |------MOB_MNHO-REQ----->| | | | |<-LGD-|<-----MOB_BSHO-RSP------| | | | | | or | | | | | | [BS initiation] | | | | |<-LGD-|<-----MOB_BSHO-REQ------| | | | | | | | | | |------------------FBU---------------->| | | | | | |-----HI---->| | | | | |<---HACK----| | |<-----------------FBACK---------------|--> | | |(LSW)>|-------MOB_HO-IND------>| forward========>| | disconnect | packets | | | connect | | | | |<-LUP-|<--------------802.16 network reentry------------->| connect | | | | |-------------------------FNA---------------------->| | |<===============================================deliver | | | | | packets | Figure 3. Predictive Fast Handover in 802.16 7.2. Reactive Mode The procedure is described as follows in case of reactive mode. Jang, et al. Expires August 31, 2006 [Page 13] Internet-Draft FMIPv6 over 802.16e February 2006 1. A BS broadcasts MOB_NBR-ADV periodically. 2. If the MN discovers a new neighbor BS in this message, it may perform scanning for it. 3. When a new BS is found through the MOB_NBR-ADV or scanning, the MN's link layer notifies it of the IP layer (fmip6) by New_BS_Found primitive. 4. Then the MN may try to resolve new neighbor's BSID to the associated AR by exchange of RtSolPr and PrRtAdv with the PAR. 5. The MN initiates handover by sending MOB_MSHO-REQ to the BS and receives MOB_BSHO-RSP from the BS. Also, the BS can initiate handover by sending MOB_BSHO-REQ to the MN. 6. When the MN receives either MOB_BSHO-RSP or MOB_BSHO-REQ from the BS, its link layer triggers Link_Going_Down to IP layer, thereby sending FBU if possible. 7. When the MN can not receive FBAck on the current link, it runs the reactive mode. After conducting handover to the target BS, the MN performs the 802.16e network entry procedure. 8. As soon as the network entry procedure is completed, the MN's link layer signals its IP layer with Link_Up and then the MN issues the FNA encapsulating FBU to the NAR. 9. Receiving FNA, the NAR verifies the availability of NCoA and forwards the inner FBU to the PAR, establishing the tunnel. 10. If the NAR detects the NCoA is already in use, it MUST discard the FBU and reply with Router Advertisement with NAACK option to the MN. Otherwise, it delivers the packets destined for NCoA to the MN. Jang, et al. Expires August 31, 2006 [Page 14] Internet-Draft FMIPv6 over 802.16e February 2006 ---------- ---------- MN L3 MN L2 | s-BS PAR | | NAR t-BS | ---------- ---------- | | | | | | |<-NBF-|<-----MOB_NBR-ADV-------| | | | | |( Scanning )| | | | |--------------(RtSolPr)-------------->| | | |<--------------PrRtAdv----------------| | | | | | | | | | | [MN initiation] | | | | | |------MOB_MSHO-REQ----->| | | | |<-LGD-|<-----MOB_BSHO-RSP------| | | | | | or | | | | | | [BS initiation] | | | | |<-LGD-|<-----MOB_BSHO-REQ------| | | | | | | | | | |-----------------(FBU)--------------->| | | | |-------MOB_HO-IND------>| | | | disconnect| | | | | | connect | | | | |<-LUP-|<--------------802.16 network reentry------------->| connect | | | | |-------------------------FNA[FBU]----------------->| | | | | |<---FBU-----| | | | | |----FBACK-->| | | | | forward | | | | | packets=========>| | |<================================================deliver | | | | | packets | Figure 4. Reactive Fast Handover in 802.16 Jang, et al. Expires August 31, 2006 [Page 15] Internet-Draft FMIPv6 over 802.16e February 2006 8. Security Considerations The security consideration of the FMIPv6 specification [3] is applicable to this document. Particularly, 802.16e architecture supports a number of mandatory authorization mechanisms, for example, EAP-TTLS, EAP-SIM and EAP-AKA, as well as, secure IP address management between the MN and its network entity. That will allow secure handover operation between the mobile node and the network entity. Further security considerations will be carefully studied along with this document. Jang, et al. Expires August 31, 2006 [Page 16] Internet-Draft FMIPv6 over 802.16e February 2006 9. Acknowledgment Many thanks IETF Mobility Working Group members of KWISF (Korea Wireless Internet Standardization Forum) for their efforts on this work. In addition, we would like to thank Alper E. Yegin, Jinhyeock Choi and Misun Do who have provided the technical advice. 10. 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", RFC 3775, June 2004. [3] Koodli, R., "Fast Handovers for Mobile IPv6", draft-ietf-mipshop-fast-mipv6-03 (work in progress), October 2004. [4] McCann, P., "Mobile IPv6 Fast Handovers for 802.11 Networks", draft-ietf-mipshop-80211fh-04 (work in progress), April 2005. [5] Mitani, K., "Unified L2 Abstractions for L3-Driven Fast Handover", draft-koki-mobopts-l2-abstractions-03 (work in progress), October 2005. [6] IEEE 802.16 TGe Working Document (Draft Standard), "Amendment for Physical and Medium Access Control Layers for Combined Fixed and Mobile Operation in Licensed Bands", 802.16e/D12, October 2005. [7] IEEE 802.21 Working Group Document (Draft Standard),"Draft IEEE Standard for Local and Metropolitan Area Networks: Media Independent Handover Services", IEEE P802.21/D00.05, January 2006. March 2004. [8] Kim, K., Kim, C., and T. Kim, "A Seamless Handover Mechanism for IEEE 802.16e Broadband Wireless Access", International Conference on Computational Science, vol. 2, pp. 527-534, 2005. Jang, et al. Expires August 31, 2006 [Page 17] Internet-Draft FMIPv6 over 802.16e February 2006 Authors' Addresses Heejin Jang Samsung Advanced Institute of Technology P.O. Box 111 Suwon 440-600 Korea Email: heejin.jang@samsung.com Junghoon Jee Electronics and Telecommunications Research Institute 161 Gajeong-dong, Yuseong-gu Daejon 305-350 Korea Email: jhjee@etri.re.kr Youn-Hee Han Samsung Advanced Institute of Technology P.O. Box 111 Suwon 440-600 Korea Email: yh21.han@samsung.com Soohong Daniel Park Samsung Electronics 416 Maetan-3dong, Yeongtong-gu Suwon 442-742 Korea Email: soohong.park@samsung.com Jaesun Cha Electronics and Telecommunications Research Institute 161 Gajeong-dong, Yuseong-gu Daejon 305-350 Korea Email: jscha@etri.re.kr Jang, et al. Expires August 31, 2006 [Page 18] Internet-Draft FMIPv6 over 802.16e February 2006 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. 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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 (2006). 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. Jang, et al. Expires August 31, 2006 [Page 19]