draft-ietf-mip4-aaa-nai-02.txt   rfc3846.txt 
Mobile IP Working Group F. Johansson Network Working Group F. Johansson
Internet-Draft ipUnplugged Request for Comments: 3846 ipUnplugged
Expires: June 11, 2004 T. Johansson Category: Standards Track T. Johansson
Bytemobile Bytemobile
December 12, 2003 June 2004
Mobile IPv4 Extension for carrying Network Access Identifiers Mobile IPv4 Extension for Carrying Network Access Identifiers
<draft-ietf-mip4-aaa-nai-02.txt>
Status of this Memo Status of this Memo
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all provisions of Section 10 of RFC2026. Internet community, and requests discussion and suggestions for
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Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved. Copyright (C) The Internet Society (2004).
Abstract Abstract
When a mobile node moves between two foreign networks it has to be When a mobile node moves between two foreign networks, it has to be
re-authenticated. If the home network has both multiple re-authenticated. If the home network has both multiple
Authentication Authorization and Accounting (AAA) servers and Home Authentication Authorization and Accounting (AAA) servers and Home
Agents (HAs) in use, the Home AAA server may not have sufficient Agents (HAs) in use, the Home AAA server may not have sufficient
information to process the re-authentication correctly (i.e., to information to process the re-authentication correctly (i.e., to
ensure that the same HA continues to be used). This document defines ensure that the same HA continues to be used). This document defines
a Mobile IP extension that carries identities for the Home AAA and HA a Mobile IP extension that carries identities for the Home AAA and HA
servers in the form of Network Access Identifiers (NAIs). The servers in the form of Network Access Identifiers (NAIs). The
extension allows a Home Agent to pass its identity (and that of the extension allows a Home Agent to pass its identity (and that of the
Home AAA server) to the mobile node, which can then pass it on to the Home AAA server) to the mobile node, which can then pass it on to the
local AAA server when changing its point of attachment. This local AAA server when changing its point of attachment. This
extension may also be used in other situations requiring extension may also be used in other situations requiring
communication of a NAI between Mobile IP nodes. communication of a NAI between Mobile IP nodes.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements terminology . . . . . . . . . . . . . . . . . . . 2
2. Requirements terminology . . . . . . . . . . . . . . . . . . . 3 3. NAI Carrying Extension . . . . . . . . . . . . . . . . . . . . 3
3.1. Processing of the NAI Carrying Extension . . . . . . . . 3
3. NAI Carrying Extension . . . . . . . . . . . . . . . . . . . . 4 4. HA Identity subtype . . . . . . . . . . . . . . . . . . . . . 4
3.1 Processing of the NAI Carrying Extension . . . . . . . . 5 5. AAAH Identity subtype . . . . . . . . . . . . . . . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . 5
4. HA Identity subtype . . . . . . . . . . . . . . . . . . . . . 5 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6
5. AAAH Identity subtype . . . . . . . . . . . . . . . . . . . . 6 9. Normative References . . . . . . . . . . . . . . . . . . . . . 6
10. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . 7 11. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 8
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7
Normative References . . . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 8
Intellectual Property and Copyright Statements . . . . . . . . 9
1. Introduction 1. Introduction
When building networks one would like to be able to have redundancy. 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 In order to achieve this, one might place multiple AAA servers in one
domain. When a mobile node registers via a visited network the domain. When a mobile node registers via a visited network, the
authentication will be handled by one of the AAA servers in the home 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 domain. At a later point, when the mobile node moves to another
visited domain it again has to be authenticated. However, due to the visited domain it again has to be authenticated. However, due to the
redundancy offered by the AAA protocol, it can not be guaranteed that redundancy offered by the AAA protocol, it can not be guaranteed that
the authentication will be handled by the same AAAH server as the 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 previous one, which can result in the new AAAH not knowing to which
the session was assigned to. This document defines a Mobile IP HA the session was assigned. This document defines a Mobile IP
extension which can be used to distribute the information needed to extension which can be used to distribute the information needed to
resolve this. resolve this.
Furthermore, the only information that is normally available about Furthermore, the only information that is normally available about
the home agent in the registration request is the IP address as the home agent in the registration request is the IP address as
defined in RFC 3344 [5]. This may unfortunately not be enough, since defined in RFC 3344 [5]. Unfortunately this may not be enough since
some AAA infrastructures (such as Diameter [6]) use realm based some AAA infrastructures (such as Diameter [6]) use realm based
routing; such a AAA infrastructure needs to know the FQDN identity of routing; such a AAA infrastructure needs to know the FQDN identity of
the home agent to be able to correctly handle the assignment of home the home agent to be able to correctly handle the assignment of the
agent. A reverse DNS lookup would only disclose the identity of the home agent. A reverse DNS lookup would only disclose the identity of
Mobile IP interface for that HA IP address, which may or may not have the Mobile IP interface for that HA IP address, which may or may not
a one-to-one correspondence with the home agent FQDN identity. This have a one-to-one correspondence with the home agent FQDN identity.
is a reason for the HA to also include its own identity in the This is a reason for the HA to also include its own identity in the
registration reply. The MIP v4 extension defined in this document registration reply. The MIP v4 extension defined in this document
also has a subtype defined by which this may be done. The HA identity also has a subtype defined by which this may be done. The HA
can then be included by the mobile node in later registration identity can then be included by the mobile node in later
requests when changing point of attachment. registration requests when changing the point of attachment.
2. Requirements terminology 2. Requirements terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [1]. document are to be interpreted as described in BCP 14, RFC 2119 [1].
The Mobile IP related terminology described in RFC 3344 [5] is used The Mobile IP related terminology described in RFC 3344 [5] is used
in this document. In addition, the following terms are used: in this document. In addition, the following terms are used:
AAAH AAAH
One of possible several AAA Servers in the Home Network One of several possible AAA Servers in the Home Network
FQDN FQDN
Fully Qualified Domain Name. Fully Qualified Domain Name.
Identity Identity
The identity of a node is equal to its FQDN. The identity of a node is equal to its FQDN.
NAI NAI
Network Access Identifier [2]. Network Access Identifier [2].
3. NAI Carrying Extension 3. NAI Carrying Extension
This section defines the NAI Carrying Extension which may be used in This section defines the NAI Carrying Extension which may be used in
Mobile IP Registration Request and Reply messages, and also in Mobile Mobile IP Registration Request and Reply messages, and also in Mobile
IP Agent Advertisements [5]. The extension may be used by any node IP Agent Advertisements [5]. The extension may be used by any node
that wants to send identity information in the form of a NAI [4]. that wants to send identity information in the form of a NAI [4].
This document also defines some subtype numbers which identify the This document also defines some subtype numbers which identify the
specific type of NAI carried, in Section 4 and Section 5. It is specific type of NAI carried in Sections 4 and 5. It is expected
expected that other types of NAI will be defined by other documents that other types of NAI will be defined by other documents in the
in the future. future.
0 1 2 3 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 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 | Length | Sub-Type | NAI ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type Type 136 (skippable) [5].
(Type to be assigned by IANA) (skippable) [5]
Length 8-bit unsigned integer. Length of the extension, in octets, Length 8-bit unsigned integer. Length of the extension, in
excluding the extension Type and the extension Length octets, excluding the extension Type and the extension Length
fields. This field MUST be set to 1 plus the total length fields. This field MUST be set to 1 plus the total length of the
of the NAI field. NAI field.
Sub-Type This field describes the particular type NAI which is Sub-Type This field describes the particular type NAI which is
carried in the NAI field. carried in the NAI field.
NAI Contains the NAI [2] in a string format. NAI Contains the NAI [2] in a string format.
3.1 Processing of the NAI Carrying Extension 3.1. Processing of the NAI Carrying Extension
When a mobile node or home agent adds a NAI Carrying Extension to a When a mobile node or home agent adds a NAI Carrying Extension to a
registration message, the extension MUST appear prior to any registration message, the extension MUST appear prior to any
authentication extensions. authentication extensions.
In the event the foreign agent adds a NAI Carrying Extension to a In the event the foreign agent adds a NAI Carrying Extension to a
registration message, the extension MUST appear prior to any registration message, the extension MUST appear prior to any
authentication extensions added by the FA. authentication extensions added by the FA.
If an HA has appended a NAI Carrying Extension to a Registration If an HA has appended a NAI Carrying Extension to a Registration
Reply to an MN, and does not receive the NAI extension in subsequent 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 Registration Request messages from the MN, the HA can assume that the
MN does not understand this NAI extension. In this case, the HA MN does not understand this NAI extension. In this case, the HA
SHOULD NOT append this NAI extension to further Registration Reply SHOULD NOT append this NAI extension to further Registration Reply
messages to the MN. messages to the MN.
4. HA Identity subtype 4. HA Identity subtype
The HA identity uses subtype 1 of the NAI Carrying Extension. It The HA identity uses subtype 1 of the NAI Carrying Extension. It
contains the NAI of the HA in the form hostname@realm. Together the contains the NAI of the HA in the form hostname@realm. Together the
hostname and realm forms the complete FQDN (hostname.realm) of the hostname and realm form the complete FQDN (hostname.realm) of the HA.
HA.
A Home Agent using this extension MUST provide it in the first A Home Agent using this extension MUST provide it in the first
Registration Reply sent to a Mobile Node which is not currently Registration Reply sent to a Mobile Node which is not currently
registered. The extension only need to be included in subsequent registered. The extension only need to be included in subsequent
Registration Replies if the same extension is included in Registration Replies if the same extension is included in
Registration Requests received from the same Mobile Node. Registration Requests received from the same Mobile Node.
A mobile node using this extension MUST, if it receives it in a A mobile node using this extension MUST, if it receives it in a
registration reply message, provide it in every subsequent registration reply message, provide it in every subsequent
registration request when re-authentication is needed. Failure to registration request when re-authentication is needed. Failure to
re-authenticate, for instance because no AAAH can be reached, will re-authenticate, for instance because no AAAH can be reached, will
result in termination of the Mobile-IP session. On initiation of a result in termination of the Mobile-IP session. Upon initiation of a
new session a new HA Identity NAI may be provided to the Mobile node, new session a new HA Identity NAI may be provided to the Mobile node,
and the requirement above will apply to the newly received NAI. and the requirement above will apply to the newly received NAI.
If the mobile node requires a specific home agent and it has the NAI If the mobile node requires a specific home agent and it has the NAI
available it MUST provide this extension in its initial registration available it MUST provide this extension in its initial registration
request. request.
A foreign agent which receives the Home Agent NAI by this extension A foreign agent which receives the Home Agent NAI by this extension
in a registration request SHOULD include the Home Agent NAI when in a registration request SHOULD include the Home Agent NAI when
requesting Mobile Node authentication through the AAA infrastructure requesting Mobile Node authentication through the AAA infrastructure
if the AAA protocol used can carry the information. if the AAA protocol used can carry the information.
5. AAAH Identity subtype 5. AAAH Identity subtype
The AAAH identity uses subtype 2 of the NAI Carrying Extension. It The AAAH identity uses subtype 2 of the NAI Carrying Extension. It
contains the NAI of the home AAA server in the form hostname@realm. contains the NAI of the home AAA server in the form hostname@realm.
Together the hostname and realm forms the complete FQDN Together the hostname and realm form the complete FQDN
(hostname.realm) of the home AAA server. (hostname.realm) of the home AAA server.
If there exists several AAA servers in the Home Network, a Home Agent If several AAA servers exist in the Home Network, a Home Agent
providing AAAH selection support according to this document MUST providing AAAH selection support according to this document MUST
provide the AAAH identity in the first Registration Reply sent to the provide the AAAH identity in the first Registration Reply sent to the
Mobile Node. The extension only need to be included in subsequent Mobile Node. The extension only needs to be included in subsequent
Registration Replies if the same extension is included in Registration Replies if the same extension is included in
Registration Requests received from the same Mobile Node. Registration Requests received from the same Mobile Node.
A mobile node SHOULD save the latest AAAH Identity received in a A mobile node SHOULD save the latest AAAH Identity received in a
registration reply message and SHOULD provide the AAAH Identity in registration reply message and SHOULD provide the AAAH Identity in
every registration request sent when re-authenticating, for every registration request sent when re-authenticating, for
efficiency reasons. Failure to reach the indicated AAAH during efficiency reasons. Failure to reach the indicated AAAH during re-
re-authentication will result in a new AAAH Identity NAI being authentication will result in a new AAAH Identity NAI being returned
returned (which should then be saved and provided in subsequent (which should then be saved and provided in subsequent registration
registration requests). Similarly, failure to re-authenticate, for requests). Similarly, failure to re-authenticate, for instance
instance because no AAAH can be reached, will result in termination because no AAAH can be reached, will result in termination of the
of the Mobile-IP session; on initiation of a new session a new AAAH Mobile-IP session; on initiation of a new session, a new AAAH
Identity NAI may be provided to the Mobile Node for re-use during Identity NAI may be provided to the Mobile Node for re-use during
later re-registrations. later re-registrations.
A foreign agent which receives the AAAH NAI by this extension in a A foreign agent which receives the AAAH NAI by this extension in a
registration request SHOULD include the AAAH NAI provided when registration request SHOULD include the AAAH NAI provided when
requesting Mobile Node authentication through the AAA infrastructure requesting Mobile Node authentication through the AAA infrastructure
if the AAA protocol used can carry the information. if the AAA protocol used can carry the information.
6. Security Considerations 6. Security Considerations
This specification introduces new Mobile IP extensions that are used This specification introduces new Mobile IP extensions that are used
to carry mobility agent and AAA server identities, in the form of to carry mobility agent and AAA server identities, in the form of
Network Access Identifiers. The Mobile IP messages that carry this Network Access Identifiers. The Mobile IP messages that carry this
extension MUST be authenticated as described in [4], unless other extension MUST be authenticated as described in [4], unless other
authentication methods have been agreed upon. Therefore, this authentication methods have been agreed upon. Therefore, this
specification does not lessen the security of Mobile IP messages. specification does not lessen the security of Mobile IP messages.
It should be noted that the identities sent in the extensions It should be noted that the identities sent in the extensions
specified herein MAY be sent in the clear over the network. However, specified herein MAY be sent in the clear over the network. However,
the authors do not envision that this information would create any the authors do not envision that this information would create
security issues. security issues.
7. IANA Considerations 7. IANA Considerations
This document defines one new mobile IP extension, and one new Mobile This document defines one new mobile IP extension, and one new Mobile
IP extension sub-type numbering space to be managed by IANA. IP extension sub-type numbering space to be managed by IANA.
Section 3 defines a new Mobile IP extension, the Mobile IP NAI Section 3 defines a new Mobile IP extension, the Mobile IP NAI
Carrying Extension. The type number for this extension is [TBD, Carrying Extension. The type number for this extension is 136. This
assigned by IANA]. This extension introduces a new sub-type extension introduces a new sub-type numbering space where the values
numbering space where the values 1 and 2 has been assigned values in 1 and 2 have been assigned in this document. Approval of new Mobile
this document. Approval of new Mobile IP NAI Carrying Extension IP NAI Carrying Extension sub-type numbers is subject to Expert
sub-type numbers is subject to Expert Review, and a specification is Review, and a specification is required [3].
required [3].
The content and format for this extension is not specific to AAA The content and format for this extension is not specific to AAA
NAIs, so if in the future new NAIs are defined which does not NAIs, so if in the future new NAIs are defined which do not strictly
strictly fall within the category of AAA NAIs, they may nevertheless fall within the category of AAA NAIs, they may nevertheless be
be accommodated within the subtype numbering space defined for the accommodated within the subtype numbering space defined for the NAI
NAI Carrying Extension defined in this document. Carrying Extension defined in this document.
The NAI Carrying Extension should be assigned a type value from both The NAI Carrying Extension should be assigned a type value from both
the IANA number space for Mobile IPv4 skippable extensions, and from the IANA number space for Mobile IPv4 skippable extensions and from
the IANA number space for Mobile IPv4 advertisement extensions. the IANA number space for Mobile IPv4 advertisement extensions.
Ideally, the numbers assigned from these two numbering spaces should Ideally, the numbers assigned from these two numbering spaces should
have the same value. have the same value.
8. Acknowledgements 8. Acknowledgements
Thanks to the original authors of the GNAIE draft, Mohamed M Khalil, Thanks to the original authors of the GNAIE document, Mohamed M
Emad Qaddoura, Haseeb Akhtar, Pat R. Calhoun. The original draft was Khalil, Emad Qaddoura, Haseeb Akhtar, and Pat R. Calhoun. The
removed from the MIP WG charter when no use was seen for the original document was removed from the MIP WG charter when no use was
extension. The original ideas has been reused in this draft. seen for the extension. The original ideas have been reused in this
document. Also thanks to Henrik Levkowetz and Kevin Purser for
Also thanks to Henrik Levkowetz and Kevin Purser for valuable valuable feedback and help when writing this document.
feedback and help when writing this draft.
Normative References 9. Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997. Levels", BCP 14, RFC 2119, March 1997.
[2] Aboba, B. and M. Beadles, "The Network Access Identifier", RFC [2] Aboba, B. and M. Beadles, "The Network Access Identifier", RFC
2486, January 1999. 2486, January 1999.
[3] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA [3] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA
Considerations Section in RFCs", BCP 26, RFC 2434, October 1998. Considerations Section in RFCs", BCP 26, RFC 2434, October 1998.
[4] Calhoun, P. and C. Perkins, "Mobile IP Network Access Identifier [4] Calhoun, P. and C. Perkins, "Mobile IP Network Access Identifier
Extension for IPv4", RFC 2794, March 2000. Extension for IPv4", RFC 2794, March 2000.
[5] Perkins, C., "IP Mobility Support for IPv4", RFC 3344, August [5] Perkins, C., "IP Mobility Support for IPv4", RFC 3344, August
2002. 2002.
[6] Calhoun, P., Loughney, J., Guttman, E., Zorn, G. and J. Arkko, [6] Calhoun, P., Loughney, J., Guttman, E., Zorn, G. and J. Arkko,
"Diameter Base Protocol", RFC 3588, September 2003. "Diameter Base Protocol", RFC 3588, September 2003.
Authors' Addresses 10. Authors' Addresses
Fredrik Johansson Fredrik Johansson
ipUnplugged AB ipUnplugged AB
Arenavagen 23 Arenavagen 23
Stockholm S-121 28 Stockholm S-121 28
SWEDEN SWEDEN
Phone: +46 8 725 5916 Phone: +46 8 725 5916
EMail: fredrik@ipunplugged.com EMail: fredrik@ipunplugged.com
Tony Johansson Tony Johansson
Bytemobile Inc Bytemobile Inc
2029 Stierlin Court 2029 Stierlin Court
Mountain View, CA 94043 Mountain View, CA 94043
USA USA
Phone: +1 650 862 0523 Phone: +1 650 862 0523
EMail: tony.johansson@bytemobile.com EMail: tony.johansson@bytemobile.com
Intellectual Property Statement 11. Full Copyright Statement
Copyright (C) The Internet Society (2004). 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
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