NETLMM WG Y. Han Internet-Draft KUT Intended status: Informational B. Park Expires: February 4, 2009 KT July 03, 2008 A Fast Handover Scheme in Proxy Mobile IPv6 draft-han-netlmm-fast-pmipv6-00 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 January 1, 2009. Abstract This memo proposes a scheme that supports a fast handover effectively in Proxy Mobile IPv6 by optimizing the associated data and signaling flows during the handover. New signaling messages, Fast PBU and Reverse PBU, are defined and utilized to expedite the handover procedure. Han & Park Expires January 1, 2009 [Page 1] Internet-Draft Fast PMIPv6 June 2008 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Protocol Operation . . . . . . . . . . . . . . . . . . . . . . 4 4. Handoff Type Considerations . . . . . . . . . . . . . . . . . . 6 5. Message Format . . . . . . . . . . . . . . . . . . . . . . . . 6 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 7.1. Normative References . . . . . . . . . . . . . . . . . . . 7 7.2. Informative References . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7 Intellectual Property and Copyright Statements . . . . . . . . . . 9 Han & Park Expires January 1, 2009 [Page 2] Internet-Draft Fast PMIPv6 June 2008 1. Introduction The PMIPv6 (Proxy Mobile IPv6) protocol provides local mobility management to a mobile node without requiring any modification of the mobile node. But, PMIPv6's handover could cause undesirable delay to the mobile nodes running real time applications like VoIP. This memo proposes a scheme that supports a fast handover effectively in PMIPv6 by optimizing the associated data and signaling flows during the handover. FMIPv6 (Fast Handover for Mobile IPv6) [RFC5268] is a well-known fast handover scheme for the host-based Mobile IPv6. It may be harnessed to enhance PMIPv6's handover performance. Actually, some schemes have been proposed based on the FMIPv6's strategy (see [I-D.xia- netlmm-fmip-mnagno] and [I-D.yokota-mipshop-pfmipv6]). However, they induce unnecessary processing overhead for re-tunneling at the MAGs, as well as inefficient usage of network bandwidth if there are no direct secure links between them. The main reason for this is that the data transport of PMIPv6 is based on the tunneling from the LMA to the MAG, not between MAGs, while the FMIPv6 and the existing schemes use the tunneling between the previous AR (PAR) and new AR (NAR) for fast handover. We propose a new PMIPv6's fast handover scheme to overcome such ineffectiveness by defining the signaling messages between LAM and MAG. The proposed scheme utilizes only pre-established bi- directional tunnels between LMA and MAGs, and does not create and utilize a bi-directional tunnel between MAGs. 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 RFC 2119 [RFC2119]. The terminology in this document is based on the definitions in [I-D.ietf-netlmm-proxymip6], in addition to the ones specified in this section: o Previous Mobile Access Gateway (PMAG): The MAG that manages mobility related signaling for the MN before handover. o New Mobile Access Gateway (NMAG): The MAG that manages mobility related signaling for the MN after handover. o Previous Point of Attachment (P-PoA): The access network device to which the MN is attached before handover. Han & Park Expires January 1, 2009 [Page 3] Internet-Draft Fast PMIPv6 June 2008 o New Point of Attachment (N-PoA): The access network device to which the MN is attached after handover. o Fast Proxy Binding Update (Fast PBU): A request message sent by an MAG to a mobile node's LMA for expediting the handover procedure. o Fast Proxy Binding Acknowledgement (Fast PBA): A reply message sent by an LMA in response to a Fast PBU message that it received from a MAG. o Reverse Proxy Binding Update (Reverse PBU): A request message sent by LMA to a mobile node's new MAG after establishing a binding between the home network prefix assigned to the mobile node and its new care-of address (Proxy-CoA). o Reverse Proxy Binding Acknowledgement (Reverse PBA): A reply message sent by a MAG in response to a Reverse PBU message that it received from an LMA. 3. Protocol Operation Because a mobile node is not directly involved with IPv6 mobility management, it is also unaware of fast handover procedure defined in this memo. All new signaling messages defined in this memo are exchanged by the MAG and the LMA. The proposed scheme is not based on the fast handover strategy defined in [RFC5268]. To reduce the handover latency due to signaling between the MAGs and the LMA, this memo only utilizes the bi-directional tunnels between the LMA and the PMAG/NMAG. That is, no tunnel creation between MAGs is required. The bi-directional tunnel between the LMA and the PMAG has been always established to provide a visited mobile node with the packet delivery service. The bi-directional tunnel between the LMA and the NMAG may be also already established because the tunnels are shared for multiple mobile nodes in PMIPv6. Han & Park Expires January 1, 2009 [Page 4] Internet-Draft Fast PMIPv6 June 2008 MN P-PoA N-PoA PMAG NMAG LMA | | | | | | |Link-specific | | | | (a) |Pre-handover | | | | |procedure | | | | | |<--------->| HO Initiate | | | (b) | |-(MN ID, New AP ID)->| | | | | | | Fast PBU | (c) | | | |----(MN ID, New PCoA)--->| | | | | | | | | | | Fast PBA | (d) | | | |<------------------------| | | | | | | | | | | | Reverse PBU | (e) | | | | |<--(MN ID,---| | | | | | HNP) | | | | | | | (f) | | | | | Reverse PBA | | | | | |------------>| (g) | | | | |<==DL data===| ~~~ | | | |\ | (h) | | | | |buffering | ~~~ | | | | | | | MN:N-PoA connection | N-PoA:MAG connection| | | (h) |<---establishment---->|<---establishment---->| | | | | | | |/ | (i) |<=================DL data====================| | | | | | | | (j) |==================UL data===================>| | | | | | |===UL data==>| | | | | | | The proposed handover procedure. Figure 1 The procedure is as follows (see Figure 1): (a) A handover is imminent and a link-specific pre-handover procedure is performed. The pre-handover procedure can be host-initiated or network-initiated. The exact procedure is out of scope. (b) P-PoA, to which the MN is currently attached, indicates the handover of the mobile node to the PMAG. The exact procedure of this indication is also out of scope. Han & Park Expires January 1, 2009 [Page 5] Internet-Draft Fast PMIPv6 June 2008 (c) The PMAG sends the Fast PBU to the LMA. The Fast PBU message MUST include the MN ID and the new PCoA, the address of NMAG, which is resolved by the New AP ID. (d) The LMA sends back the Fast PBA to the PMAG. (e) The LMA establishes a binding between the home network prefix (HNP) assigned to the mobile node and its new PCoA. The LMA sends the Reverse PBU to the NMAG. The Reverse PBU message MUST include the MN ID and the HNP of the mobile node. (f) The NMAG sends back the Reverse PBA to the LMA. (g) If the bi-directional tunnel is not established between the NMAG and the LMA, a new tunnel is established. The LMA starts to transfer packets destined for the mobile node via the NMAG. If the mobile node has not established a connection with NMAG at this time, the NMAG starts to buffer the packets. (h) The mobile node hands over to the New Access Network. (i) The mobile node establishes a connection (e.g. radio channel) with the N-PoA, which in turn triggers the establishment of the connection between the N-PoA and NMAG. The exact procedure of this procedure is also out of scope. (j) The NMAG starts to transfer packets destined for the mobile node via the N-PoA. (k) The uplink packets from the mobile node are sent to the NMAG via the N-PoA and the NMAG forwards them to the LMA. It is noted that the Reverse PBU and PBA are the alternates of the original PBU and PBU of PMIPv6. That is, the proposed scheme incorporates the main part of PMIPv6 procedure in the fast handover procedure, and thus any subsequent PMIPv6 procedure is not necessary. 4. Handoff Type Considerations TBD 5. Message Format TBD Han & Park Expires January 1, 2009 [Page 6] Internet-Draft Fast PMIPv6 June 2008 6. Security Considerations TBD 7. References 7.1. Normative References [I-D.ietf-netlmm-proxymip6] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K., and B. Patil, "Proxy Mobile IPv6", draft-ietf-netlmm-proxymip6-18 (work in progress), May 2008. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC5268] Koodli, R., "Mobile IPv6 Fast Handovers", RFC 5268, June 2008. 7.2. Informative References [I-D.xia-netlmm-fmip-mnagno] Xia, F. and B. Sarikaya, "Mobile Node Agnostic Fast Handovers for Proxy Mobile IPv6", draft-xia-netlmm-fmip-mnagno-02 (work in progress), November 2007. [I-D.yokota-mipshop-pfmipv6] Yokota, H., Chowdhury, K., Koodli, R., Patil, B., and F. Xia, "Fast Handovers for PMIPv6", draft-yokota-mipshop-pfmipv6-02 (work in progress), February 2008. Authors' Addresses Youn-Hee Han KUT Gajeon-Ri, 307, Byeongcheon-Myeon Cheonan, Chungnam Korea Phone: +82 41 560 1486 Email: yhhan@kut.ac.kr Han & Park Expires January 1, 2009 [Page 7] Internet-Draft Fast PMIPv6 June 2008 Byungjoo Park KT Jeonmin-Dong, Yusung-Go Deajoen, Chungnam Korea Email: bjpark@kt.co.kr Han & Park Expires January 1, 2009 [Page 8] Internet-Draft Fast PMIPv6 June 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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