INTERNET DRAFT James Kempf Category: Standards Track Pat R. Calhoun Title: draft-calhoun-mobileip-proactive-fa-00.txt Sun Microsystems, Inc. Date: January 2000 Foreign Agent Assisted Hand-off Status of this Memo This document is an individual contribution for consideration by the Mobile IP Working Group of the Internet Engineering Task Force. Comments should be submitted to the diameter@ipass.com mailing list. Distribution of this memo is unlimited. This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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. Copyright (C) The Internet Society 1999. All Rights Reserved. Abstract The Mobile IP WG has been investigating how its protocol can be used in environments that require fast hand-off, especially important for real-time applications such as voice and video. Certain link layers, such as those used in cellular networks, allow for the measurement of signal strength, which is typically used to determine when a hand-off Calhoun, Kempf expires July 2000 [Page 1] INTERNET DRAFT January 2000 is required. This specification defines extensions to the Mobile IP protocol, which allows the Foreign Agent to send an unsolicited message to the Mobile Node, requesting that the Mobile Node register with a new Foreign Agent. Table of Contents 1.0 Introduction 1.1 Requirements language 2.0 Operation 2.1 Foreign Agent Considerations 2.2 Mobile Node Considerations 3.0 Mobile Node Hand-Off Request 4.0 Acknowledgements 5.0 IANA Considerations 6.0 Security Considerations 7.0 References 8.0 Authors' Addresses 9.0 Full Copyright Statement 1.0 Introduction The Mobile IP WG has been investigating how its protocol can be used in environments that require fast hand-off, especially important for real-time applications such as voice and video [2]. Certain link layers, such as those used in cellular networks, allow for the measurement of signal strength, which is typically used to determine when a hand-off is required [3]. The Mobile IP protocol [1] currently requires that a Mobile Node listen for advertisements in order to detect that a hand-off is required, which can delay the hand-off. Furthermore, it is questionable whether advertisements are appropriate in a network whose bandwidth is considered scarce, such as the cellular networks. This specification defines extensions to the Mobile IP protocol [1], that allows the Foreign Agent to send an unsolicited message to the Mobile Node, requesting that the Mobile Node register with a new Foreign Agent. 1.1 Requirements language In this document, the key words "MAY", "MUST, "MUST NOT", "optional", "recommended", "SHOULD", and "SHOULD NOT", are to be interpreted as described in [4]. Calhoun, Kempf expires July 2000 [Page 2] INTERNET DRAFT January 2000 2.0 Operation This section describes modifications to the Mobile IP protocol used when the Foreign Agent determines that the Mobile Node could be better served by another Foreign Agent within it's network. 2.1 Foreign Agent Considerations When the Foreign Agent detects that a Mobile Node could be better served through another Foreign Agent, it issues a Binding Update message [5] to the new Foreign Agent, informing it that it should inform the Mobile Node to send a Registration Request. The Binding Update contains the Mobile Node's home address, the security association it shares with the Mobile Node and it's Home Agent. Note that the mechanism used by the FA to make the determination that the Mobile Node should hand-off is outside the scope of this specification. +-----+ | oFA | +-----+ hand-off | +----+ request | Binding +----+ | MN |<-----------\ | Update | HA | +----+ | | +----+ | | v ^ Reg| +-----+ | Req \---------->| nFA |-----------/ +-----+ Reg Req Figure 1 - Mobile Node hand-off Upon receipt of the Binding Update, the new Foreign Agent issues a hand-off request to the Mobile Node, which includes the MN-FA authentication extension, using the MN-FA security association information received in the Binding Update. The hand-off request MAY be retransmitted periodically until the Mobile Node's Registration Request is received. The new Foreign Agent does the normal registration message processing, including adding the FA-HA authentication extension. During this time, the HA still sends the Mobile Node's packets to the old Foreign Agent, which are still delivered to the Mobile Node (if possible), or forwarded to the new Foreign Agent for future delivery (if necessary). Upon receipt of the Home Agent's Registration Reply, the new Foreign Agent forwards the message to the Mobile Node, while issuing the Calhoun, Kempf expires July 2000 [Page 3] INTERNET DRAFT January 2000 Binding Response to the old Foreign Agent. This message MAY be used by the old Foreign Agent to clean up resources it had allocated to the Mobile Node. 2.2 Mobile Node Considerations Upon receipt of the hand-off request from a new Foreign Agent, the Mobile Node SHOULD still accept data packets from the old Foreign Agent, until the Registration Reply has been received. The hand-off request SHOULD include the MN-FA Authentication Extension [1], using a pre-established security association, or the SA it shared with the old Foreign Agent. 3.0 Mobile Node Hand-Off Request The UDP header is followed by the Mobile IP fields shown below: 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 |S|B|D|M|G|V|rsv| Lifetime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Home Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Previous Foreign Agent | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | New Foreign Agent | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + Identification + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extensions ... +-+-+-+-+-+-+-+- Type TBD (Hand-off Request) S Simultaneous bindings MUST be set to zero. B Broadcast datagrams MUST be set to zero. D Decapsulation by mobile node MUST be set to zero. M Minimal encapsulation is set if the Foreign Agent supports minimal encapsulation. Calhoun, Kempf expires July 2000 [Page 4] INTERNET DRAFT January 2000 G GRE encapsulation is set if the Foreign Agent supports GRE encapsulation. V Set to zero. rsv Reserved bits; sent as zero Lifetime The maximum lifetime the Foreign Agent will accept in the Mobile Node's registration request. A value of 0xffff indicates infinity. Home Address The IP address of the mobile node. Previous Foreign Agent The IP address of the previous Foreign Agent. New Foreign Agent The IP address for the new Foreign Agent. Identification A 64-bit field that is set to zero. Extensions The fixed portion of the Hand-off Request is followed by one or more Mobile IP Extensions. The Mobile-Foreign Authentication Extension SHOULD be included in all Hand- off Requests. 4.0 Acknowledgements The authors would like to thank Charles Perkins for his valuable feedback. 5.0 IANA Considerations This specification introduces a new value in the Mobile IP type field. This value MUST NOT conflict with values specified in [1], or any other Mobile IP extension document. 6.0 Security Considerations This specification introduces a new Mobile IP message sent by a new Foreign Agent to request that a Mobile Node register with it. It is highly recommended that the Hand-off Request message include a Calhoun, Kempf expires July 2000 [Page 5] INTERNET DRAFT January 2000 Mobile-Foreign Authentication Extension to avoid malicious hosts sending such messages to mobiles. 7.0 References [1] C. Perkins, Editor. "IP Mobility Support". RFC 2002. October 1996. [2] T. Hiller et al. "Cdma2000 Wireless Data Requirements for AAA". draft-hiller-cdma2000-AAA-00.txt (work in progress). October 1999. [3] U. Black. "2nd Generation Wireless Networks". Prentice-Hall. New York. 1999. [4] S. Bradner. "Key words for use in RFCs to Indicate Requirement Levels". BCP 14. RFC 2119. March 1997. [5] C. Perkins and D. Johnson. "Route Optimization in Mobile IP". draft-ietf-mobileip-optim-08.txt (work in progress). Feburary 1999. 8.0 Authors' Addresses Questions about this memo can be directed to: James Kempf Network and Security Research Center, Sun Labs Sun Microsystems, Inc. 15 Network Circle Menlo Park, California, 94025 USA Phone: 1-650-786-7733 Fax: 1-650-786-6445 E-mail: james.kempf@eng.sun.com Pat R. Calhoun Network and Security Research Center, Sun Labs Sun Microsystems, Inc. 15 Network Circle Menlo Park, California, 94025 USA Phone: 1-650-786-7733 Fax: 1-650-786-6445 E-mail: pcalhoun@eng.sun.com Calhoun, Kempf expires July 2000 [Page 6] INTERNET DRAFT January 2000 9.0 Full Copyright Statement Copyright (C) The Internet Society (1999). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. 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