Network Working Group F. Xia Internet-Draft B. Sarikaya Expires: April 27, 2009 Huawei USA October 24, 2008 Mobile IPv6 Handover Using Home Agent Buffering draft-xia-mipshop-ha-buffering-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 27, 2009. Xia & Sarikaya Expires April 27, 2009 [Page 1] Internet-Draft MIPv6 Handover Using HA Buffering October 2008 Abstract In Mobile IPv6, when a Mobile Node (MN) moves from one Access Router(AR) to another, there is a period during which the MN is unable to send or receive packets because of link switching delay and IP protocol operations. This document specifies a mechanism which enhances Mobile IPv6 protocol signaling to support the creation of a transient binding cache entry in a Home Agent (HA) which is used for buffering downlink packets during this period. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Protocol Operation . . . . . . . . . . . . . . . . . . . . . . 3 3.1. General Approach . . . . . . . . . . . . . . . . . . . . . 4 3.2. Mobile Node Operations . . . . . . . . . . . . . . . . . . 5 3.3. Home Agent Operations . . . . . . . . . . . . . . . . . . . 5 4. Message Format . . . . . . . . . . . . . . . . . . . . . . . . 6 4.1. Packet Buffering option . . . . . . . . . . . . . . . . . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 6. IANA consideration . . . . . . . . . . . . . . . . . . . . . . 6 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 8.1. Normative References . . . . . . . . . . . . . . . . . . . 7 8.2. Informative references . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 Intellectual Property and Copyright Statements . . . . . . . . . . 9 Xia & Sarikaya Expires April 27, 2009 [Page 2] Internet-Draft MIPv6 Handover Using HA Buffering October 2008 1. Introduction When a MN moves from one AR to another, there is a period during which the MN is unable to send or receive packets because of link switching delay and IP protocol operations. Fast handovers for Mobile IPv6 (FMIPv6) [RFC5268] describes a mechanism that reduces the handover latency and packet loss through signalling between a previous AR and a new AR. Hierarchical Mobile IPv6 (HMIPv6)[RFC5380] introduces a network entity named Mobility Anchor Point (MAP) which is used for reducing the amount of signalling between the MN, its Correspondent Node(CN), and its Home Agent(HA). Either of the local mobility handling mechanisms, FMIPv6 or HMIPv6, is dealing with some extra mobility management entities besides the MN and HA, such as previous AR and new AR in FMIPv6, or MAPs in HMIPv6. In some scenarios, e.g. the MN moves from one administrative domain to another, it is very hard to deploy FMIPv6 or HMIPv6. As a complimentary solution, a HA based handover mechanism is proposed here. When the MN decides to switch to another access router, the MN indicates the HA to buffer incoming packets. After the HA receives an indication that the MN has completed the handover process, the HA delivers the buffered packets. This enhancement can improve greatly the performance of mobile internet applications which mostly rely on packet-loss sensentive TCP. However, it has limited improvement on real-time service, such as Voice over IP. 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]. 3. Protocol Operation Xia & Sarikaya Expires April 27, 2009 [Page 3] Internet-Draft MIPv6 Handover Using HA Buffering October 2008 3.1. General Approach +-----+ +-----+ +-----+ +-----+ | MN | | PAR | | NAR | | HA | +-----+ +-----+ +-----+ +-----+ | | | | | 1 Network Entry | | | |<------------------->| | | | | 2 BU | | |------------------------------------------------------->| | | 3 BA | | |<------------------------------------------------------>| | | | | | 4 bi-directional tunnel | |<======================================================>| | | | | 5 Handover trigger | | | | | | | | 6 BU(transient) | |------------------------------------------------------->| | | | | | | | 7 forwarding | | | and buffering | 8 BA(transient) | |<-------------------------------------------------------| | | | | | 9 Network Re-entry | | |<------------------------------->| | | | | | | 10|BU(new CoA)| | |------------------------------------------------------->| | | | | | 11|BA(new CoA)| | |<-------------------------------------------------------| | | | 12 stopping buffering and | | | delivering buffered packets | | | | | 13 bi-directional tunnel | |<======================================================>| Figure 1: General Approach 1. The MN enters into network and attaches a PAR. Authentication is usually necessary in this step. Xia & Sarikaya Expires April 27, 2009 [Page 4] Internet-Draft MIPv6 Handover Using HA Buffering October 2008 2. After successful CoA(hereafter called previous CoA to differentiate new CoA) configuration and bootstraping processing, the MN sends Binding Update(BU) message to register the CoA in the HA. 3. In reply to the BU, a Binding Acknowledgement(BA) is delivered to the MN from the HA. 4. A bi-directional tunnel is established after the BU/BA exchange. All of the previous steps are in line with specification described in [RFC3775] 5. When signal strength is degrading or packet loss rate is increasing the MN may decide to change links. Alternatively, the network can aslo initiate handover by singaling the MN. 6. The handover trigger promotes the MN sending a BU message. A Packet Buffering option Section 4.1 is included in the message. The source address of the message is the CoA configured when the MN attaches the PAR. 7. In addition to forwarding downlink packets to the MN, the HA begins to buffer them for a duration which is indicated in the lifetime field of Packet Buffering option Section 4.1. On the other hand, the HA updates binding cache entry of the MN with new lifetime of the BU message. 8. The HA acknowledges the MN with BA message. 9. When the MN moves to the NAR, the MN performs network entry procedure. A new CoA is configured. 10. The MN sends a BU message with the new CoA as the source address. 11. Once receiving the BU, the HA creates a new binding cach entry which binds the MN's home address with the new CoA. 12. The HA stops buffering downlink packets for MN, delivers all buffered packets to MN's new CoA, and obsoletes the old binding cache with previous CoA registered. 13. All traffic destined to the MN is conveyed through the newly established bi-directional tunnel. 3.2. Mobile Node Operations As an optional enhancement, the document provide an mechanism to reduce packet loss during handovers. When the MN decides to switch to another access router, the MN indicates the HA to buffer incoming packets through a transient BU/BA exchange. Once successfully attaching to a new access router, the MN retrieves all the buffered packets from the HA. 3.3. Home Agent Operations The enhancement capability is configurable in the HA. When the feature is disabled, the HA just ignores the Packet Buffering option defined in Section 4.1. Otherwise, the HA SHOULD buffer the downlink Xia & Sarikaya Expires April 27, 2009 [Page 5] Internet-Draft MIPv6 Handover Using HA Buffering October 2008 traffic. 4. Message Format 4.1. Packet Buffering option The Packet Buffering option described in this section can be present in a BU and BA. The HA receiving BU message with this option will buffer the incoming packets destined to the MN for a lifetime which is negotiated through BU/BA exchange. 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 | Length | Reserved | Lifetime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: TDB by IANA Length: 8-bit unsigned integer indicating the length of the option in octets, excluding the Type and the Length fields. Reserved: To be used in the future. Lifetime: Lifetime in the unit of 100ms. When lifetime expires, the HA will purge all the buffered packets for the MN. TDB 5. Security Considerations Malicious MNs possible make use of the mechanism to deplete HA's buffer space. The HA can configure limited buffering space for each MN to couteract the impact. Only one mobility option is defined in this document, and there is no additional security concerns introduced. 6. IANA consideration Xia & Sarikaya Expires April 27, 2009 [Page 6] Internet-Draft MIPv6 Handover Using HA Buffering October 2008 7. Acknowledgements TDB 8. References 8.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC5380] Soliman, H., Castelluccia, C., ElMalki, K., and L. Bellier, "Hierarchical Mobile IPv6 (HMIPv6) Mobility Management", RFC 5380, October 2008. [RFC5268] Koodli, R., "Mobile IPv6 Fast Handovers", RFC 5268, June 2008. [RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in IPv6", RFC 3775, June 2004. 8.2. Informative references Xia & Sarikaya Expires April 27, 2009 [Page 7] Internet-Draft MIPv6 Handover Using HA Buffering October 2008 Authors' Addresses Frank Xia Huawei USA 1700 Alma Dr. Suite 500 Plano, TX 75075 Phone: +1 972-509-5599 Email: xiayangsong@huawei.com Behcet Sarikaya Huawei USA 1700 Alma Dr. Suite 500 Plano, TX 75075 Phone: +1 972-509-5599 Email: sarikaya@ieee.org Xia & Sarikaya Expires April 27, 2009 [Page 8] Internet-Draft MIPv6 Handover Using HA Buffering October 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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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. Xia & Sarikaya Expires April 27, 2009 [Page 9]