Network Working Group M. Nakhjiri, Ed.
Internet-Draft Huawei USA
Intended status: Informational K. Chowdhury
Expires: December 8, 2007 Starent Networks
A. Lior
Bridgewater Systems
K. Leung
Cisco Systems
June 6, 2007
Mobile IPv4 RADIUS requirements
draft-ietf-mip4-radius-requirements-03.txt
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Copyright Notice
Copyright (C) The IETF Trust (2007).
Abstract
This document provides an applicability statement as well as a scope
definition for specifying RADIUS extensions to support Mobile IPv4.
The goal is to allow specification of RADIUS attributes to assist the
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Mobile IPv4 signaling procedures.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Goals and Non-Goals . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.2. Non-Goals . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
6. Security considerations . . . . . . . . . . . . . . . . . . . . 5
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6
8.1. Normative References . . . . . . . . . . . . . . . . . . . 6
8.2. Informative References . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
Intellectual Property and Copyright Statements . . . . . . . . . . 8
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1. Introduction
The Mobile IPv4 working group has developed extensions for the
registration process [RFC3344] to allow the MN and mobility agents to
request assistance from the AAA server in authentication [RFC4721]
and creation of security associations [RFC3957] all based on the pre-
established trust relationship between the MN and its home AAA
server. However, on the AAA side, currently only Diameter provides
specification for interaction with Mobile IP agents [RFC4004]
In the absence of IETF standardized RADIUS attributes for support of
MIPv4, different wireless SDOs have taken the path of developing VSAs
for dynamic bootstrapping of Mobile IPv4 registration procedure. The
use of different VSAs and different RADIUS procedures for the same
purpose of Mobile IPv4 bootstrapping at different SDOs will cause a
lack interoperability between these wireless standards, potentially
hindering mobility across these wireless networks.
To respond to the described issue, it is desired to standardize a set
of RADIUS attributes within IETF to allow a consistent and
interoperable interaction with RADIUS based AAA infrastructure during
the Mobile IPv4 Registration procedure. The bootstrapping attributes
can include configuration parameters as well as material used for
provisioning security of Mobile IPv4 messaging (authentication) as
defined by [RFC3957].
2. 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 [RFC2119].
3. Goals and Non-Goals
Since this document serves as requirement specification for RADIUS
extensions supporting Mobile IPv4 interaction with RADIUS
infrastructure, the goals and non-goals refer to only those RADIUS
extensions that are reqiuired for support of Mobile IPv4.
3.1. Goals
The scope of the work is to standardize RADIUS attributes and to
define the procedure by which the Mobile IPv4 agents, e.g. Home
agent (HA) and Foreign Agent (FA) map the Mobile IP registration
message fields into the proposed RADIUS attributes and vice versa.
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o It is required of the RADIUS servers to be able to understand and
process the attributes described in this specification to perform
verification of authentication extensions specified in [RFC4721].
RADIUS proxies are expected to be able to process these
attributes.
o All RADIUS work MUST be backward compatible with existing RADIUS
RFCs, including RFCs 2865-2869, 3162, 3575, 3576, 3579, 3580 and
4668-4671.
o It is also required of the Mobile IP agents (FA and HA) to operate
as RADIUS clients (NASes in context of RFC 2865) when translating
RADIUS signaling into Mobile IP signaling and vice versa. Details
on the behavior of Mobile IP agents as RADIUS clients are to be
provided by the solution draft desribing the RADIUS extensions for
Mobile IP support.
3.2. Non-Goals
The scope of this work is to only standardize RADIUS attributes and
to define the procedure by which the Mobile IPv4 agents, e.g. Home
agent (HA) and Foreign Agent (FA) map the Mobile IP registration
message fields into the proposed RADIUS attributes and vice versa.
It is not the intention to extend the functionality of existing
RADIUS servers or protocol. More specifically, the following are
NON-GOALS:
o Enhancing RADIUS Security: Creating new security properties for
RADIUS, such as creating key transport capabilities is not the
goal. No new security mechanisms are to be defined for the
transport of RADIUS Access Requests in relation to support of
Mobile IPv4 bootstrapping. Existing RADIUS authentication
procedures, e.g. Message-Authenticator (80) described in RFC2869,
are used. The security considerations for use of RADIUS in
bootstrapping Mobile IPv4 are described in a later section of this
document.
o Enhancing RADIUS transport reliability: Transport properties of
RADIUS remain intact. No new reliability mechanisms are defined
in the transport of such Access Requests.
o Extending RADIUS message set: RADIUS extesions for boostrapping
Mobile IPv4 are not to define new RADIUS messages. Diameter
Mobile IP application [RFC4004] has defined new command codes for
support of Mobile IP signaling, depending on whether Diameter
server is dealing with a Mobile IP HA or an FA. RADIUS currently
does not have any messages that correspond to these Diameter
commands. Instead, RADIUS extensions for Mobile IPv4
bootstrapping need to provide proposals for new RADIUS attributes
that facilitates Diameter-RADIUS messaging translation without
defining any new RADIUS messaging. At the same time, the RADIUS
extensions for Mobile IPv4 need to re-use Diameter AVPs to the
fullest extent possible.
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o RFC2977 compatibilty: Extending RADIUS in a way that fulfills the
full list of requirements in [RFC2977] will not be attempted.
4. Attributes
A specification of the RADIUS extensions for Mobile IPv4 needs to
describe the full set of attributes required for RADIUS-Mobile IP
interaction. While some of the attributes may already be
standardized, others will require standardization and IANA type
assignments.
5. IANA Considerations
This requirement document does not allocate any numbers, so there are
no IANA considerations. On the other hand, solution documentations
for RADIUS support of Mobile IPv4 will likely introduce new RADIUS
attributes. Thus those documents will need new attribute type
numbers assigned by IANA.
6. Security considerations
This document defines no new requirements or security mechanisms for
RADIUS. As such, the existing RADIUS security considerations
described previously apply, and no additional security considerations
are added here. For instance, the concern of using AAA protocols
that use hop-by-hop security (Diameter/RADIUS) to distribute keys is
nothing new. In both Diameter and RADIUS the assumption is that
intermediary nodes are trusted.
When it comes to protecting attributes in Access Request, RFC 2868
section 3.5 provides a mechanism for encrypting RADIUS attributes
(RFC 2868 section 3.5). There is also work in progress to define key
wrap mechanisms for RADIUS [zorn-radius-keywrap]. The key wrap
process can be used to transmit sensitive material, such as keys,
that require specific privacy protection. It is also possible to
protect RADIUS transactions using IPsec (e.g. as in RFC3579).
7. Acknowledgements
The authors would like to thank Alan DeKok for review and feedback.
8. References
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8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", March 1997.
[RFC2977] Glass, S. and Perkins, "Mobile IP Authentication,
Authorization, and Accounting Requirements", October 2000.
[RFC3344] Perkins, C., "IP Mobility Support", August 2002.
[RFC3957] Perkins, C. and P. Calhoun, "AAA Registration Keys for
Mobile IP", March 2005.
[RFC4004] Calhoun, P. and C. Perkins, "Diameter Mobile IP
application", May 2004.
[RFC4721] Perkins, C. and P. Calhoun, "Mobile IP Challenge/Response
Extensions (Revised)", January 2007.
[zorn-radius-keywrap]
Zorn, G., "RADIUS Attributes for the Delivery of Keying
Material", draft-zorn-radius-keywrap-12 (work in
progress).
8.2. Informative References
[I-D.nakhjiri-radius-mip4]
Nakhjiri, M. and Et. Al., "RADIUS Mobile IPv4 extensions,
draft-nakhjiri-radius-mip4-02.txt", Internet
Draft draft-nakhjiri-radius-mip4-02, October 2005.
[RFC2868] Zorn, G., "RADIUS Attributes for Tunnel Protocol Support",
June 2000.
[RFC3579] Aboba, B. and P. Calhoun, "RADIUS (Remote Authentication
Dial In User Service) Support For Extensible
Authentication Protocol (EAP)", September 2003.
Authors' Addresses
Madjid Nakhjiri (editor)
Huawei USA
Email: mnakhjiri@huawei.com
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Kuntal Chowdhury
Starent Networks
Email: kchowdhury@starentnetworks.com
Avi Lior
Bridgewater Systems
Email: avi@bridgewatersystems.com
Kent Leung
Cisco Systems
170 West Tasman Drive
San Jose, CA 95134
US
Email: kleung@cisco.com
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