Network Working Group V. Sastry Internet-Draft K. Leung
Expires: July 13, 2006Intended status: Standards Track A. Patel Expires: March 18, 2007 Cisco Systems January 09,September 14, 2006 Mobile IPv4 Message String Extension draft-ietf-mip4-message-string-ext-00.txtdraft-ietf-mip4-message-string-ext-01.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 July 13, 2006.March 18, 2007. Copyright Notice Copyright (C) The Internet Society (2006). Abstract This document specifies a new extension for use in Mobile IPv4. This extension can be added by the Home Agent and the Foreign Agent to Registration Reply message. This extension carries a text string that is intended for the user of the Mobile Node. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Mobile IPv4 Message String Extension Format . . . . . . . . . 5 4. Operation and Use of the Message String Extension . . . . . . 7 5. Security Considerations . . . . . . . . . . . . . . . . . . . 8 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10 8. Normative References . . . . . . . . . . . . . . . . . . . . . 911 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 1012 Intellectual Property and Copyright Statements . . . . . . . . . . 1113 1. Introduction This document specifies a new skippable extension that can be added by Foreign Agent and Home Agent in registration message targeted for the Mobile Node. Such a message may be either a Registration Reply or Registration Revocation (i.e. collocated Care-of Address mode). For the Registration Reply message, this extension can be added regardless of whether the registration has succeeded or failed. Content of the text string in this extension and its usage by Mobile Node is implementation specific. The text string in this extension is intended for the user of the Mobile Node. For example, this message can be displayed on the Mobile Node's user interface, logged or handled in any other implementation dependent way, depending on the form of the Mobile Node. Typical contents of the text string will indicate registration failure reason, or a welcome message on successful registration. This is important as the failure reason code gives very limited information for interpretation by the user of the Mobile Node. A string like "registration failed : Prepaid Quota for the user is exhausted", "registration success : Unauthorized Access is Prohibited", can give a human readable description of the result of Mobile IP registration. 2. Terminology The keywords "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. 3. Mobile IPv4 Message String Extension Format The Message String Extension conforms to the Short Extension format specified for Mobile IPv4 [RFC3344]. The Message String Extension is a skippable extension. 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 | Sub-Type | Text .... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: To be assigned by IANA. An 8-bit identifier of the type mobility option. Length: 8-bit unsigned integer, equaling 1 plus the length in octets of the Text Sub-Type: 1: Extension is added by Home Agent 2: Extension is added by Foreign Agent Text: The Text field is one or more octets, and its contents are implementation dependent. It is intended to be human readable, and MUST NOT affect operation of the protocol. It is recommended that the message contain UTF-8 encoded 10646 [RFC2279][RFC3629] characters. The number of octets in the UTF-8 representation of the message is exactly the value of the Length field minus one. 4. Operation and Use of the Message String Extension The Message String Extension is only valid for use within Mobile IPv4 Registration Reply and Registration Revocation messages. The Message String Extension is a skippable extension. Either Home Agent or Foreign Agent or both can add Message String Extension to registration messages. Usage of Text field of the Message String Extension is implementation dependent. For example, this message can be displayed on the Mobile Node's user interface, logged or handled in an implementation dependent way, depending on the form of the Mobile Node. Home Agent or Foreign Agent or both, MAY add the extension to each registration message to a Mobile Node. However, Mobile Node may throttle how often the user is notified of the message (either via display on user interface, logging, etc.) For example, Home Agent may reject the first Registration Request due to prepaid quota for the user is reached and may attach a Message String Extension with the text "Prepaid quota reached. Please contact www.paymore.com to update balance". Mobile Node could display this on the user interface. As a response user of the Mobile Node may take the required action to update the prepaid account and retry the registration process. Home Agent may accept this Registration Request and attach a Message String Extension with the text "Welcome to www.serviceprovider.com". Mobile Node could display this on the user interface thus confirming successful creation of binding on Home Agent. 5. Security Considerations Message String Extension can be added by Home Agent or Foreign Agent or both. If the extension is added by the Home Agent (extension with subtype 1) to Registration Reply or Registration Revocation message, it MUST appear before Mobile-Home Authentication Extension [RFC3344]. If the the Mobile Node cannot understand this extension, it should be skipped. If the extension is added by the Foreign Agent (extension with subtype 2) to Registration Reply message, it MUST appear after Mobile-Home Authentication Extension [RFC3344] whenever present. Also the extension MUST appear before the Mobile-Foreign Authentication Extension whenever present. If Mobile Node cannot understand this extension, it should be skipped. 6. IANA Considerations This specification reserves one number for the Message String Extension Section 3 from the space of numbers for skippable mobility extensions (i.e., 128-255) defined for Mobile IPv4 [RFC3344] at http://www.iana.org/assignments/mobileip-numbers. The value 145 is recommended for this extension. This specification also creates a new subtype space for the type number of this extension. The subtype values 1 and 2 are defined in this specification. The subtype value 1 is reserved for use by Home Agent and subtype value 2 is reserved for use by Foreign Agent. Other values can be allocated from this number space by IANA actions. 7. Acknowledgements The authors would like to thank Avi Lior, Curtis Provost and Henrik Levkowetz for their useful comments on an eariler version of this document. 8. Normative References [FA-ERR] Perkins, C., "Foreign Agent Error Extension for Mobile IPv4", draft-ietf-mip4-faerr-02.txt (work in progress), September 2005. [RFC2279] Yergeau, F., "UTF-8, a transformation format of ISO 10646", RFC 2279, January 1998.[RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson, "Remote Authentication Dial In User Service (RADIUS)", RFC 2865, June 2000. [RFC3344] Perkins, C., "IP Mobility Support for IPv4", RFC 3344, August 2002. [RFC3543] Glass, S. and M. Chandra, "Registration Revocation in Mobile IPv4", RFC 3543, August 2003. [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO 10646", STD 63, RFC 3629, November 2003. Authors' Addresses Venkateshwara Sastry Cisco Systems Akkithimanahalli, O'Shaugnessy Road Bangalore 560085 India Phone: +91 80-51033757 Email: firstname.lastname@example.org Kent Leung Cisco Systems 170 W. Tasman Drive San Jose, CA 95134 US Phone: +1 408-526-5030 Email: email@example.com Alpesh Patel Cisco Systems 170 W. Tasman Drive San Jose, CA 95134 US Phone: +1 408-853-9580 Email: firstname.lastname@example.org Full 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. 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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 currentlyprovided by the Internet Society.IETF Administrative Support Activity (IASA).