draft-ietf-mip4-message-string-ext-02.txt   draft-ietf-mip4-message-string-ext-03.txt 
MIP4 V. Sastry MIP4 V. Sastry
Internet-Draft Samsung Electronics Internet-Draft Samsung Electronics
Intended status: Standards Track K. Leung Intended status: Standards Track K. Leung
Expires: July 19, 2007 A. Patel Expires: September 2, 2007 A. Patel
Cisco Systems Cisco Systems
January 15, 2007 March 1, 2007
Mobile IPv4 Message String Extension Mobile IPv4 Message String Extension
draft-ietf-mip4-message-string-ext-02.txt draft-ietf-mip4-message-string-ext-03.txt
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware 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 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. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
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and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on July 19, 2007. This Internet-Draft will expire on September 2, 2007.
Copyright Notice Copyright Notice
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2007).
Abstract Abstract
This document specifies a new extension for use in Mobile IPv4. This 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 extension can be added by the Home Agent and the Foreign Agent to
Registration Reply messages. This extension carries a text string Registration Reply messages. This extension carries a text string
that is intended for the user of the Mobile Node. that is intended for the user of the Mobile Node.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Mobile IPv4 Message String Extension Format . . . . . . . . . 5 3. Mobile IPv4 Message String Extension Format . . . . . . . . . 5
4. Operation and Use of the Message String Extension . . . . . . 7 4. Operation and Use of the Message String Extension . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . 8 5. Security Considerations . . . . . . . . . . . . . . . . . . . 7
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9
8. Normative References . . . . . . . . . . . . . . . . . . . . . 11 8. Normative References . . . . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11
Intellectual Property and Copyright Statements . . . . . . . . . . 13 Intellectual Property and Copyright Statements . . . . . . . . . . 12
1. Introduction 1. Introduction
This document specifies a new skippable extension that can be added This document specifies a new skippable extension that can be added
by the Foreign Agent and Home Agent in any registration message by the Foreign Agent and Home Agent in any registration message
targeted for the Mobile Node. Such a message may be either a targeted for the Mobile Node. Such a message may be either a
Registration Reply or Registration Revocation (i.e. co-located Registration Reply or Registration Revocation (i.e. co-located
Care-of Address mode). For the Registration Reply message, this Care-of Address mode). For the Registration Reply message, this
extension can be added regardless of whether the registration has extension can be added regardless of whether the registration has
succeeded or failed. succeeded or failed.
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Extension comes from the Home Agent Extension comes from the Home Agent
2: 2:
Extension comes from the Foreign Agent Extension comes from the Foreign Agent
Text: Text:
The Text field is one or more octets, and its contents are The Text field is one or more octets, and its contents are
implementation dependent. It is intended to be human readable, implementation dependent. It is intended to be human readable,
and MUST NOT affect operation of the protocol. It is RECOMMENDED and MUST NOT affect operation of the protocol. The message MUST
that the message contain UTF-8 encoded 10646 [RFC3629] characters. be in UTF-8 encoded ISO-10646 [RFC3629] characters. The number of
The number of octets in the encoded representation of the message octets in the encoded representation of the message is always
is always exactly the value of the Length field minus one. (In exactly the value of the Length field minus one. (In the UTF-8
the UTF-8 case, the number of unicode characters represented by case, the number of unicode characters represented by this octet
this octet sequence may be smaller than the number of octets.) 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 4. Operation and Use of the Message String Extension
The Message String Extension is only valid for use within Mobile IPv4 The Message String Extension is only valid for use within Mobile IPv4
Registration Reply and Registration Revocation messages. The Message Registration Reply and Registration Revocation messages. The Message
String Extension is a skippable extension. Either the Home Agent or String Extension is a skippable extension. Either the Home Agent or
Foreign Agent or both can add the Message String Extension to Foreign Agent or both can add the Message String Extension to
registration messages. The usage of Text field of the Message String registration messages. The usage of Text field of the Message String
Extension is implementation dependent. For example, the message can Extension is implementation dependent. For example, the message can
be displayed on the Mobile Node's user interface, logged, or handled be displayed on the Mobile Node's user interface, logged, or handled
in an implementation dependent way, depending on the form of the in an implementation dependent way, depending on the form of the
Mobile Node. Mobile Node. The Mobile Node may throttle how often the user is
notified of the message.
The Mobile Node may throttle how often the user is notified of the As an example, the Home Agent may reject the first Registration
message (either via display on user interface, logging, etc.) For Request due to prepaid quota for the user is reached and may attach a
example, the Home Agent may reject the first Registration Request due Message String Extension with the text "Prepaid quota reached.
to prepaid quota for the user is reached and may attach a Message Please contact www.paymore.example.com to update balance". The
String Extension with the text "Prepaid quota reached. Please Mobile Node could display this on the user interface. As a response,
contact www.paymore.example.com to update balance". The Mobile Node the user of the Mobile Node may take the required action to update
could display this on the user interface. As a response, the user of the prepaid account and retry the registration process. The Home
the Mobile Node may take the required action to update the prepaid Agent may accept this Registration Request and attach a Message
account and retry the registration process. The Home Agent may String Extension with the text "Welcome to
accept this Registration Request and attach a Message String www.serviceprovider.example.com". The Mobile Node could display this
Extension with the text "Welcome to www.serviceprovider.example.com". on the user interface thus confirming successful creation of binding
The Mobile Node could display this on the user interface thus on Home Agent.
confirming successful creation of binding on Home Agent.
In the case that the message is not originated by the Home Agent
itself, but for instance is received from a RADIUS server [RFC2865],
it could be received in some other encoding than UTF-8. If so, the
Home Agent MUST convert the message to UTF-8 encoded ISO-10646
[RFC3629] characters.
5. Security Considerations 5. Security Considerations
The Message String Extension can be added by the Home Agent or The Message String Extension can be added by the Home Agent or
Foreign Agent or both. Foreign Agent or both. The protection of the extension is based on
the ordering method specified for message authentication in RFC 3344
[RFC3344] and emphasized below.
If the extension is added by the Home Agent (extension with subtype If the extension is added by the Home Agent (extension with subtype
1) to a Registration Reply or Registration Revocation message, it 1) to a Registration Reply or Registration Revocation message, it
MUST appear before Mobile-Home Authentication Extension [RFC3344]. MUST appear before Mobile-Home Authentication Extension [RFC3344].
If the extension is added by the Foreign Agent (extension with If the extension is added by the Foreign Agent (extension with
subtype 2) to a Registration Reply message, it MUST appear after subtype 2) to a Registration Reply message, it MUST appear after
Mobile-Home Authentication Extension [RFC3344] whenever present. Mobile-Home Authentication Extension [RFC3344] whenever present.
Also the extension MUST appear before the Mobile-Foreign Also the extension MUST appear before the Mobile-Foreign
Authentication Extension whenever present. Authentication Extension whenever present. However, since security
association between the Mobile Node and Foreign Agent is optional, it
is possible that the extension is not authenticated in this case.
There is no confidentiality provided by the extension; the message is
transferred unencrypted, and if sensitive information is sent for
display purposes, it may need to be protected by other means.
6. IANA Considerations 6. IANA Considerations
This specification reserves one number for the Message String This specification reserves one number for the Message String
Extension in Section 3 from the space of numbers for skippable Extension in Section 3 from the space of numbers for skippable
mobility extensions (i.e., 128-255) defined for Mobile IPv4 [RFC3344] mobility extensions (i.e., 128-255) defined for Mobile IPv4 [RFC3344]
at http://www.iana.org/assignments/mobileip-numbers. at http://www.iana.org/assignments/mobileip-numbers.
The value 145 is suggested for this extension. The value 145 is suggested for this extension.
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number of this extension. The subtype values 1 and 2 are defined in 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 this specification. The subtype value 1 is reserved for use by Home
Agent and subtype value 2 is reserved for use by Foreign Agent. Agent and subtype value 2 is reserved for use by Foreign Agent.
Similar to the procedures specified for Mobile IPv4 [RFC3344] number Similar to the procedures specified for Mobile IPv4 [RFC3344] number
spaces, future allocations from this number space require expert spaces, future allocations from this number space require expert
review [RFC2434]. review [RFC2434].
7. Acknowledgements 7. Acknowledgements
The authors would like to thank Avi Lior, Curtis Provost and Henrik The authors would like to thank Avi Lior, Curtis Provost and Henrik
Levkowetz for their useful comments on an eariler version of this Levkowetz for their useful comments on an earlier version of this
document. document. Also, Russ Housley, Vidya Narayanan, Blake Ramsdell, Paul
Hoffman, and Jeff Hutzelman provided justifications to mandate the
need for only UTF-8 encoding in the message and solicited better
clarifications in the security consideration section.
8. Normative References 8. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 2434, IANA Considerations Section in RFCs", BCP 26, RFC 2434,
October 1998. October 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, [RFC3344] Perkins, C., "IP Mobility Support for IPv4", RFC 3344,
August 2002. August 2002.
[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
10646", STD 63, RFC 3629, November 2003. 10646", STD 63, RFC 3629, November 2003.
Authors' Addresses Authors' Addresses
Venkateshwara Sastry Venkateshwara Sastry
Samsung Electronics Samsung Electronics
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