Mobile IP Working Group F. Johansson
Internet-Draft ipUnplugged
Expires: March 19, 2004 T. Johansson
Bytemobile
September 19, 2003
Mobile IPv4 Extension for AAA Network Access Identifiers
draft-ietf-mip4-aaa-nai-00.txt
Status of this Memo
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.
This Internet-Draft will expire on March 19, 2004.
Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved.
Abstract
When a mobile node moves between two foreign networks it has to be
reauthenticated. If the home network has multiple Authentication
Authorization and Accounting (AAA) servers the reauthentication
request may not be received by the same Home AAA server as previous
authentication requests. In order for the new Home AAA server to be
able to forward the request to the correct Home Agent it has to know
the identity of the Home Agent. This document defines a Mobile IP
extension that enables the HA to pass its identity to the mobile node
which can then pass it on to the new AAA server when changing point
of attachment.
Johansson & Johansson Expires March 19, 2004 [Page 1]
Internet-Draft MIPv4 Extension for AAA NAIs September 2003
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements terminology . . . . . . . . . . . . . . . . . . . 3
3. AAA NAI Extension . . . . . . . . . . . . . . . . . . . . . . 4
3.1 Processing of the AAA NAI Extension . . . . . . . . . . 5
4. HA Identity subtype . . . . . . . . . . . . . . . . . . . . . 5
5. AAAH Identity subtype . . . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . 6
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7
Normative References . . . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 8
Intellectual Property and Copyright Statements . . . . . . . . 9
Johansson & Johansson Expires March 19, 2004 [Page 2]
Internet-Draft MIPv4 Extension for AAA NAIs September 2003
1. Introduction
When building networks one would like to be able to have redundancy.
In order to achieve this, one might place multiple AAA servers in one
domain. When a mobile node registers via a visited network the
authentication will be handled by one of the AAA servers in the home
domain. At a later point, when the mobile node moves to another
visited domain it again has to be authenticated. However, due to the
redundancy offered by the AAA protocol, it can not be guaranteed that
the authentication will be handled by the same AAAH server as the
previous one which can result in the new AAAH not knowing which HA
the session was assigned to. This document defines a Mobile IP
extension which can be used to distribute the information needed to
resolve this.
To solve this the home agent MUST include the NAI of the AAAH server
in the registration reply message, which the mobile node then MUST
include in every subsequent registration request sent to a foreign
agent when changing point of attachment.
Furthermore, the only information that is normally available about
the home agent in the registration request is the IP address as
defined in RFC 3344 [1]. This is unfortunately not enough, since the
AAA infrastructure needs to know the FQDN identity of the home agent
to be able to correctly handle the assignment of home agent. A
reverse DNS lookup would only disclose the identity of the Mobile IP
interface for that HA IP address, which may or may not have a
one-to-one correspondence with the home agent FQDN identity. This is
the reason why the HA also includes its own identity in the
registration reply. It can then be included by the mobile node in
the coming registration requests when changing point of attachment.
2. Requirements 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 RFC 2119 [4].
The Mobile IP related terminology described in RFC 3344 [1] is used
in this document. In addition, the following terms are used:
AAAH
One of possible several AAA Servers in the Home Network
FQDN
Fully Qualified Domain Name.
Johansson & Johansson Expires March 19, 2004 [Page 3]
Internet-Draft MIPv4 Extension for AAA NAIs September 2003
Identity
The identity of a node is equal to its FQDN.
NAI
Network Access Identifier [2].
3. AAA NAI Extension
This section defines the AAA NAI Extension which may be carried in
Mobile IP Registration Request and Reply messages [1]. The extension
may be used by any node that wants to send identity information in
the form of a NAI [3]. This document defines subtype numbers which
identify the NAI as a HA identity and a Home AAA identity,
respectively.
Johansson & Johansson Expires March 19, 2004 [Page 4]
Internet-Draft MIPv4 Extension for AAA NAIs September 2003
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 | NAI ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
(Type to be assigned by IANA) (skippable) [1]
Length 8-bit unsigned integer. Length of the extension, in octets,
excluding the extension Type and the extension Length
fields. This field MUST be set to 1 plus the total length
of the NAI field.
Sub-Type This field describes the type of the entity which owns the
NAI. The following subtypes are defined:
1 HA Identity NAI (Section 4)
2 AAAH Identity NAI (Section 5)
NAI Contains the NAI [2] in a string format.
3.1 Processing of the AAA NAI Extension
When a mobile node or home agent adds a AAA NAI extension to a
registration message, the extension MUST appear prior to any
authentication extensions.
In the event the foreign agent adds an AAA NAI extension to a
registration message, the extension MUST appear prior to any
authentication extensions added by the FA.
If an HA has appended an AAA NAI extension to a Registration Reply to
an MN, and does not receive the NAI extension in subsequent
Registration Request messages from the MN, the HA can assume that the
MN does not understand this NAI extension. In this case, the HA
SHOULD NOT append this NAI extension to further Registration Reply
messages to the MN.
4. HA Identity subtype
The HA identity uses subtype 1 of the AAA NAI Extension. It contains
the NAI of the HA in the form hostname@realm. Together the hostname
and realm forms the complete FQDN (hostname.realm) of the HA.
The Home Agent MUST provide this in the first Registration Reply sent
Johansson & Johansson Expires March 19, 2004 [Page 5]
Internet-Draft MIPv4 Extension for AAA NAIs September 2003
to the Mobile Node destined through the AAA infrastructure. The
extension only need to be included in subsequent Registration Replies
if the same extension is included in Registration Requests received
from the same Mobile Node.
A mobile node that recieves this extension in a registration reply
message MUST provide it in every registration request when
re-authentication is needed. If the mobile node requests a specific
home agent and it has the information available it MUST provide this
extension in its initial registration request.
A foreign agent which receives the Home Agent NAI by this extension
in a registration request SHOULD include the Home Agent NAI when
requesting Mobile Node authentication through the AAA infrastructure
if the AAA protocol used can carry the information.
5. AAAH Identity subtype
The AAAH identity uses subtype 2 of the AAA NAI Extension. It
contains the NAI of the home AAA server in the form hostname@realm.
Together the hostname and realm forms the complete FQDN
(hostname.realm) of the home AAA server.
If there exists several AAA servers in the Home Network, the Home
Agent MUST provide this in the first Registration Reply sent to the
Mobile Node. The extension only need to be included in subsequent
Registration Replies if the same extension is included in
Registration Requests received from the same Mobile Node.
A mobile node MUST always save the latest AAAH Identity received in a
registration reply message and MUST provide the AAAH Identity in
every registration request sent when re-authenticating.
A foreign agent which receives the AAAH NAI by this extension in a
registration request SHOULD include the AAAH NAI provided when
requesting Mobile Node authentication through the AAA infrastructure
if the AAA protocol used can carry the information.
6. Security Considerations
This specification introduces new Mobile IP extensions that are used
to carry mobility agent and AAA server identities, in the form of
Network Access Identifiers. It is assumed that the Mobile IP
messages that would carry these extensions would be authenticated in
the manner that is described in [4], or any follow-on authentication
mechanisms. Therefore, this specification does not lessen the
security of Mobile IP messages.
Johansson & Johansson Expires March 19, 2004 [Page 6]
Internet-Draft MIPv4 Extension for AAA NAIs September 2003
It should be noted that the identities sent in the extensions
specified herein MAY be sent in the clear over the network. However,
the authors do not envision that this information would create any
security issues.
7. IANA Considerations
This document defines one new mobile IP extension, and one new Mobile
IP extension sub-type numbering space to be managed by IANA.
Section 3 defines a new Mobile IP extension, the Mobile IP AAA NAI
Extension. The type number for this extension is [TBD, assigned by
IANA]. This extension introduces a new sub-type numbering space
where the values 1 and 2 has been assigned values in this document.
Approval of new Mobile IP AAA NAI Extension sub-type numbers is
subject to Expert Review, and a specification is required [5].
The value assigned to the AAA NAI Extension should be taken from the
IANA number space for Mobile IPv4 skippable extensions.
8. Acknowledgements
Thanks to the original authors of the GNAIE draft, Mohamed M Khalil,
Emad Qaddoura, Haseeb Akhtar, Pat R. Calhoun. The original draft
was removed from the MIP WG charter when no use was seen for the
extension. The original ideas has been reused in this draft.
Also thanks to Henrik Levkowetz and Kevin Purser for valuable
feedback and help when writing this draft.
Normative References
[1] Perkins, C., "IP Mobility Support for IPv4", RFC 3344, August
2002.
[2] Aboba, B. and M. Beadles, "The Network Access Identifier", RFC
2486, January 1999.
[3] Calhoun, P. and C. Perkins, "Mobile IP Network Access Identifier
Extension for IPv4", RFC 2794, March 2000.
[4] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[5] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA
Considerations Section in RFCs", BCP 26, RFC 2434, October 1998.
Johansson & Johansson Expires March 19, 2004 [Page 7]
Internet-Draft MIPv4 Extension for AAA NAIs September 2003
Authors' Addresses
Fredrik Johansson
ipUnplugged AB
Arenavagen 23
Stockholm S-121 28
SWEDEN
Phone: +46 8 725 5916
EMail: fredrik@ipunplugged.com
Tony Johansson
Bytemobile Inc
2029 Stierlin Court
Mountain View, CA 94043
USA
Phone: +1 650 862 0523
EMail: tony.johansson@bytemobile.com
Johansson & Johansson Expires March 19, 2004 [Page 8]
Internet-Draft MIPv4 Extension for AAA NAIs September 2003
Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any
intellectual property 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; neither does it represent that it
has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and
standards-related documentation can be found in BCP-11. Copies of
claims of rights made available for publication 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 implementors or users of this specification can
be obtained from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive
Director.
Full Copyright Statement
Copyright (C) The Internet Society (2003). 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 assignees.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
Johansson & Johansson Expires March 19, 2004 [Page 9]
Internet-Draft MIPv4 Extension for AAA NAIs September 2003
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
Johansson & Johansson Expires March 19, 2004 [Page 10]
