NETEXT Working Group Yujin Lim Internet Draft University of Suwon Expires: January 7, 2010 Sanghyun Ahn University of Seoul Jungsoo Park HyeongJun Kim ETRI/SRC July 6, 2009 LMA Handovers for Proxy Mobile IPv6 draft-lim-netext-lma-handover-00.txt Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. This document may not be modified, and derivative works of it may not be created, except to format it for publication as an RFC or to translate it into languages other than English. 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 January 7, 2010. Copyright Notice Copyright (c) 2009 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights Lim, et al. Expires January 7, 2010 [Page 1] Internet-Draft LMA Handovers for Proxy Mobile IPv6 July 2009 and restrictions with respect to this document. Abstract This document describes a mechanism for context transfer between Local Mobility Anchors (LMAs) in a large Proxy MIPv6 domain to provide the IP ongoing session continuity of mobile nodes. In order to enhance the performance of the LMA handover, a bi-directional tunnel between a previous LMA and a new target LMA is established. Table of Contents 1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. LMA Handover for PMIPv6 Overview . . . . . . . . . . . . . . . 4 4.1 Protocol Operation . . . . . . . . . . . . . . . . . . . . 5 5. Other Considerations . . . . . . . . . . . . . . . . . . . . 7 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 6.1. Normative References . . . . . . . . . . . . . . . . . . . 7 6.2. Informative References . . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 Lim, et al. Expires January 7, 2010 [Page 2] Internet-Draft LMA Handovers for Proxy Mobile IPv6 July 2009 1. Requirements notation 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]. 2. Introduction The Proxy Mobile IPv6 (PMIPv6) [RFC5213] domain refers to the network where the mobility management of a Mobile Node (MN) is handled using the Proxy Mobile IPv6 protocol. The Proxy Mobile IPv6 domain includes Local Mobility Anchors (LMAs) and Mobile Access Gateways (MAGs). This document describes a mechanism to provide the ongoing session continuity to a MN during the handover from one LMA to another LMA in a Proxy Mobile IPv6 domain. This specification addresses the following problems: o Who and when to trigger the LMA handover. o Who and how to select a new target LMA. o How to transfer the context information between LMAs. o Database table updates of network entities. o Other considerations. When a previous MAG and a new MAG share the same LMA, the previous MAG transfers the context information of a MN to the new MAG via the bi-directional tunnel between them by using the Fast Handovers for Proxy Mobile IPv6 (PFMIPv6) [PFMIPv6] protocol. This document provides a mechanism for transferring the context information of a MN from a Previous LMA (PLMA) to a new LMA (NLMA) by establishing a bi-directional tunnel. 3. Terminology This document reuses the terminology from [RFC5213], [RFC3775] and [PFMIPv6]. The following terms and abbreviations are additionally used in this document. Boundary Mobile Access Gateway (bMAG): The MAG that has connections from more than one LMA. The bMAG decides when it tiggers the LMA handover and requests a previous LMA to initiate the LMA handover. Previous Local Mobility Anchor (PLMA): It is the topological anchor point for the MN's home network prefix(es) and is the entity that manages the MN's binding state. Lim, et al. Expires January 7, 2010 [Page 3] Internet-Draft LMA Handovers for Proxy Mobile IPv6 July 2009 +----+ +----+ |PLMA| |NLMA| +----+ +----+ | | | | //\\ //\\ // \\ // \\ // \\ // \\ +---- // -----\\------------- //------\\----+ ( // \\ IPv4/IPv6 // \\ ) ( // \\ Network // \\ ) +--// -----------\\--------//------------\\-+ // \\ // \\ // \\ // \\ // \\ // \\ | | | +..........+ +..........+ +..........+ . +----+ . . +----+ . . +----+ . . |MAG1| . . |bMAG| . . |MAG3| . . +----+ . . +----+ . . +----+ . . . . | . . . . . . | . . . . ------------> {MN} --------------> . . . . . . . +..........+ +..........+ +..........+ Figure 1: Reference network for the LMA handover The PLMA initiates to hand over the IP mobility session and forwards the context information of a MN to the target LMA. The PLMA has the functional capabilities of the home agent as defined in Mobile IPv6 base specification [RFC3775]. New Local Mobility Anchor (NLMA): The LMA that receives the context information of a MN from PLMA and maintains the current location of the MN. The NLMA has the functional capabilities of the foreign agent as defined in Mobile IPv6 base specification [RFC3775]. 4. LMA Handovers for PMIPv6 Overview To deliver the context information of a MN from a PLMA to a NLMA efficiently, a LMA Handover Request (LMA_HO_Req) and a LMA Handover Response (LMA_HO_Resp) messages are exchanged between a bMAG and a PLMA. In the messages, MN'Identifier (MN ID), MN Link-layer Identifier (MN-LL-ID) and MN's Home Network Prefix (MN-HNP) are included. Lim, et al. Expires January 7, 2010 [Page 4] Internet-Draft LMA Handovers for Proxy Mobile IPv6 July 2009 In this document, the policy profile of a MN stored in the remote policy store is extended to include the address of the LMA at which the MN is currently located (Foreign Agent LMAA: FA LMAA) as well as the MN ID, the address of the LMA which acts as the home agent of the MN (Home Agent LMAA: HA LMAA). The reference network is illustrated in Figure 1. 4.1. Protocol Operation The sequence of events illustrating the LMA handover is shown in Figure 2. The detailed description is as follows: (a) The MN detects a new link and reports the identifications of itself (MN ID) and the access point (New AP ID) to which the MN is most likely to move. (b) The access network (AN), to which the MN is currently attached, indicates the movement of the MN to the bMAG. This step is defined in [PFMIPv6]. (c) The bMAG sends a LMA_HO_Req message to the PLMA to initiate the LMA handover. (d) The PLMA selects the NLMA and sends a LMA_HO_Init message with the context information of the MN to the NLMA. The PLMA is assumed to maintain the information on the other LMAs in the same PMIPv6 domain, such as the message exchanges between LMAs, the external information input and the reception of the information from the AAA/Policy store. However, this is out of the scope of this document. (e) The NLMA received the LMA_HO_Init message creates a bind cache entry (BCE) of the corresponding MN and, then, a bi-directional tunnel is set up between the PLMA and the NLMA by sending a LMA_HAck message to the PLMA. (f) The PLMA notifies bMAG of the completion of the context transfer regarding the MN from the PLMA to the NLMA by sending a LMA_HO_Resp message to the bMAG. (g) The bMAG initiates the tunne setup between the bMAG and the NLMA by sending a Proxy Binding Update (PBU) message to the NLMA. Lim, et al. Expires January 7, 2010 [Page 5] Internet-Draft LMA Handovers for Proxy Mobile IPv6 July 2009 AAA MN AN bMAG PLMA NLMA /Policy Store | | | | | | | Report | | | | | (a) |-(MN ID,-->| | | | | | New AP ID)| | | | | | |HO Initiate | | | (b) | |--(MN ID,->| | | | | | New AP ID)| | | | | | |LMA_HO_Req | | | (c) | | |--(MN ID)->| | | | | | |LMA_HO_Init| | (d) | | | |-(MN ID, ->| | | | | | MN-LL-ID,| | | | | | MN-HNP) | | | | | | | | (e) | | | |<-LMA_HAck-| | | | | | (MN ID) | | | | | | | | | | | |==Bi-Dir===| | | | | | Tunnel | | | | |LMA_HO_Resp| | | (f) | | |<-(MN ID)--| | | | | | | | | (g) | | | --------PBU---------->| | | | | | | Update | (h) | | | | |-(MN ID,->| | | | | | NLMAA) | | | | | | | | | | | |Update_Ack| (i) | | | | |<-(MN ID)-| | | | | | | (j) | | | <-------PBA---------- | | | | | | | | | | |=====Bi-Dir Tunnel=====| | | | | | | | (k) | | | |==========>|=# | |<======================|<========DL data=========# | | | | | | | (l) |======================>|=========UL data======>| | | | | | | | Figure 2: LMA handover for PMIPv6 (h) The NLMA sends an Update message to the remote policy store to inform the policy store of the fact that the NLMA is the new LMA maintaining the MN's current location information and the binding information. Lim, et al. Expires January 7, 2010 [Page 6] Internet-Draft LMA Handovers for Proxy Mobile IPv6 July 2009 (i) The remote policy store sends an Update_Ack message to the NLMA in order to let the NLMA know that the FA LMAA of the MN in the policy store is set to the NLMA. (j) The bi-directional tunnel between the bMAG and the NLMA is completely established by the NLMA's sending a Proxy Binding Acknowledgement (PBA) message to the bMAG. (k) The data downloaded from the correspondent node (CN) arrives at the PLMA which is the home agent LMA of the MN, and the PLMA forwards the downloaded data to the NLMA through the tunnel between them. Then, the NLMA sends the data to the MN via the bMAG. For the efficiency of the data delivery, it is possible to consider the route optimization additionally. (l) The data uploaded from the MN to the CN are delivered to the CN via the bMAG and the NLMA in that order. 5. Other Considerations Security issues for this document follow those for PMIPv6 [RFC5213] and PFMIPv6 [PFMIPv6]. In PMIPv6, the MAG and LMA are assumed to share security associations. In PFMIPv6, the MAGs are assumed to share security associations. This document also assumes that the LMAs that participate in handover have adequate prior agreement and trust relationship between each other. A MN can be multi-homed. Multi-homing issues for this document follow that for [LMA_Redirect]. A single LMA entity should have the control over all possible multi-homed mobility sessions the MN has. All mobility sessions that a multi-homed MN may have SHOULD be anchored in the single LMA entity. 6. References 6.1. Normative References [RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K., and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3775] Johnson, D., "Mobility Support in IPv6", RFC 3775, June 2004. Lim, et al. Expires January 7, 2010 [Page 7] Internet-Draft LMA Handovers for Proxy Mobile IPv6 July 2009 6.2. Informative References [PFMIPv6] Yokota, H., Chowdhury, K., Koodli, R., Patil, B., and Xia, F., "Fast Handovers for Proxy Mobile IPv6", draft-ietf-mipshop-pfmipv6-05.txt, June 2009. [LMA_Redirect] Korhonen, J., Gundavelli, S., and Yokota, H., "Runtime LMA Assignment Support for Proxy Mobile IPv6", draft-korhonen-netext-redirect-02.txt, May 2009. Authors' Addresses Yujin Lim University of Suwon San 2-2, Wau-ri, Bongdam-eup Hwaseong-si, Gyeonggi-do, 445-743 Korea Email: yujin@suwon.ac.kr Sanghyun Ahn University of Seoul 90, Cheonnong-dong, Tongdaemun-gu Seoul 130-743 Korea Email: ahn@uos.ac.kr Jungsoo Park ETRI/SRC 161 Gajeong-dong, Yuseong-gu Daejeon 305-350 Korea Email: pjs@etri.re.kr HyeongJun Kim ETRI/SRC 161 Gajeong-dong, Yuseong-gu Daejeon 305-350 Korea Email: khj@etri.re.kr Lim, et al. 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