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 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 December 8, 2007. 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 Nakhjiri, et al. Expires December 8, 2007 [Page 1] Internet-Draft Mobile IP4 RADIUS Requirements June 2007 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 Nakhjiri, et al. Expires December 8, 2007 [Page 2] Internet-Draft Mobile IP4 RADIUS Requirements June 2007 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. Nakhjiri, et al. Expires December 8, 2007 [Page 3] Internet-Draft Mobile IP4 RADIUS Requirements June 2007 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. Nakhjiri, et al. Expires December 8, 2007 [Page 4] Internet-Draft Mobile IP4 RADIUS Requirements June 2007 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 Nakhjiri, et al. Expires December 8, 2007 [Page 5] Internet-Draft Mobile IP4 RADIUS Requirements June 2007 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 Nakhjiri, et al. Expires December 8, 2007 [Page 6] Internet-Draft Mobile IP4 RADIUS Requirements June 2007 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 Nakhjiri, et al. Expires December 8, 2007 [Page 7] Internet-Draft Mobile IP4 RADIUS Requirements June 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). 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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 ietf-ipr@ietf.org. Acknowledgment Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). Nakhjiri, et al. Expires December 8, 2007 [Page 8]