Network Working GroupMIP4 V. Sastry Internet-Draft K. LeungSamsung Electronics Intended status: Standards Track A. PatelK. Leung Expires: March 18,July 19, 2007 A. Patel Cisco Systems September 14, 2006January 15, 2007 Mobile IPv4 Message String Extension draft-ietf-mip4-message-string-ext-01.txtdraft-ietf-mip4-message-string-ext-02.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 March 18,July 19, 2007. Copyright Notice Copyright (C) The Internet Society (2006).IETF Trust (2007). 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.messages. 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 . . . . . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12 Intellectual Property and Copyright Statements . . . . . . . . . . 13 1. Introduction This document specifies a new skippable extension that can be added by the Foreign Agent and Home Agent in any registration message targeted for the Mobile Node. Such a message may be either a Registration Reply or Registration Revocation (i.e. collocatedco-located Care-of Address mode). For the Registration Reply message, this extension can be added regardless of whether the registration has succeeded or failed. ContentThe content of the text string in this extension and its usage by the 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, loggedlogged, or handled in any other implementation dependent way, depending on the form of the Mobile Node. Typical contents of the text string will indicate a registration failure reason, or give 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. AFor example, a string like "registration failed : Prepaid Quota for the user is exhausted", "registration success : Unauthorized Access is Prohibited",exhausted" can give a human readable description of the result of Mobile IP registration. 2. Terminology The keywordskey 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 2119.2119 [RFC2119]. 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, equalinginteger. Length of the extension, in bytes, excluding the extension Type and the extension Length fields. This field MUST be set to 1 plus the total length in octetsof the Text field. Sub-Type: 1: Extension is added bycomes from the Home Agent 2: Extension is added bycomes from the 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 recommendedRECOMMENDED that the message contain UTF-8 encoded 10646 [RFC3629] characters. The number of octets in the UTF-8encoded representation of the message is always exactly the value of the Length field minus one. (In the UTF-8 case, the number of unicode characters represented by this octet sequence may be smaller than the number of octets.) Other encoding methods than UTF-8 may only be used in closed environments where it can be guaranteed that both message sender and receiver know the exact encoding method, and know that the encoding method is different from UTF-8. 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 the Home Agent or Foreign Agent or both can add the Message String Extension to registration messages. UsageThe usage of Text field of the Message String Extension is implementation dependent. For example, thisthe message can be displayed on the Mobile Node's user interface, loggedlogged, 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,The Mobile Node may throttle how often the user is notified of the message (either via display on user interface, logging, etc.) For example, the 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.comwww.paymore.example.com to update balance". The Mobile Node could display this on the user interface. As a responseresponse, the user of the Mobile Node may take the required action to update the prepaid account and retry the registration process. The Home Agent may accept this Registration Request and attach a Message String Extension with the text "Welcome to www.serviceprovider.com".www.serviceprovider.example.com". The Mobile Node could display this on the user interface thus confirming successful creation of binding on Home Agent. 5. Security Considerations The Message String Extension can be added by the Home Agent or Foreign Agent or both. If the extension is added by the Home Agent (extension with subtype 1) to a 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 theextension is added by the Foreign Agent (extension with subtype 2) to a 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 in 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 recommendedsuggested 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 allocatedSimilar to the procedures specified for Mobile IPv4 [RFC3344] number spaces, future allocations from this number space by IANA actions.require expert review [RFC2434]. 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[RFC2119] Bradner, S., "Key words for Mobile IPv4", draft-ietf-mip4-faerr-02.txt (workuse in progress), September 2005. [RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson, "Remote Authentication Dial In User Service (RADIUS)",RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 2865, June 2000.2434, October 1998. [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 560085Samsung Electronics Bagmane Lake View, 'Block -B' 66/1, Bagmane Tech Park, Byrasandra, C. V. Raman Nagar Bangalpre 560093 India Phone: +91 80-51033757+91-80-41819999 Email: firstname.lastname@example.org@samsung.com 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).IETF Trust (2007). 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. 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 SOCIETYSOCIETY, THE IETF TRUST 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. Intellectual Property The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. 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 email@example.com. Acknowledgment Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA).