Mobility for IPv6 (mip6) H. Tschofenig Internet-Draft T. Tsenov Expires: January 12, 2006 Siemens G. Giaretta TILab J. Bournelle GET/INT July 11, 2005 Diameter applicability for AAA-HA Interface in Mobile IPv6 draft-tschofenig-mip6-aaa-ha-diameter-00.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 January 12, 2006. Copyright Notice Copyright (C) The Internet Society (2005). Abstract In Mobile IPv6 deployment a need for interface between the Home Agent and the AAA infrastructure of the Mobile Service Provider (MSP) and the Mobility Service Authorizer (MSA) has been identified. This interface should meet a list of requirements. This document provides Tschofenig, et al. Expires January 12, 2006 [Page 1] Internet-Draft AAA-HA interface in Mobile IPv6 July 2005 an overview description of the functionalities and design of Diameter protocol which could meet the specified goals. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.1 General goals . . . . . . . . . . . . . . . . . . . . . . 5 3.1.1 G1.1 - G1.4 Security . . . . . . . . . . . . . . . . . 5 3.1.2 Dead peer detection - the AAA-HA interface should support inactive peer detection. . . . . . . . . . . . 5 3.2 Service Authorization . . . . . . . . . . . . . . . . . . 5 3.2.1 G2.1. The AAA-HA interface should allow the use of Network Access Identifier (NAI) to identify the mobile node. . . . . . . . . . . . . . . . . . . . . . 5 3.2.2 G2.2. The HA should be able to query the AAAH server to verify Mobile IPv6 service authorization for the mobile node. . . . . . . . . . . . . . . . . . 6 3.2.3 G2.3. The AAAH server should be able to enforce explicit operational limitations and authorization restrictions on the HA.( e.g. packet filters, QoS parameters). . . . . . . . . . . . . . . . . . . . . . 6 3.2.4 G2.4 - G2.6. Issues addressing the maintenance of a Mobile IPv6 session by the AAAH server, e.g. authorization lifetime, extension of the authorization lifetime and explicit session termination by the AAAH server side. . . . . . 6 3.2.5 G2.7. The AAAH server should be able to retrieve the Mobile IPv6 state associated to a specific MN from the correspondent HA. This may be useful to periodically verify the Mobile IPv6 service status. . 7 3.3 Accounting - G3.1. The AAA-HA interface must support the transfer of accounting records needed for service control and charging . . . . . . . . . . . . . . . . . . . 7 3.4 Mobile Node Authentication (G4.1. and G4.2.) . . . . . . . 7 3.5 Provisioning of configuration parameters . . . . . . . . . 8 4. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . 9 5. Security considerations . . . . . . . . . . . . . . . . . . . 10 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 8.1 Normative References . . . . . . . . . . . . . . . . . . . 13 8.2 Informative References . . . . . . . . . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 13 Intellectual Property and Copyright Statements . . . . . . . . 15 Tschofenig, et al. Expires January 12, 2006 [Page 2] Internet-Draft AAA-HA interface in Mobile IPv6 July 2005 1. Introduction In Mobile IPv6 deployment, authentication, authorization and accounting issues in the protocol operations are approached by definition of an interface between the Home Agent (HA) and the AAA infrastructure of the Mobility Service Provider (MSP). [3] document presents a number of bootstrapping scenarios using the AAA-HA interface and defines a list of requirements that the interface should cover. This document deals with the functionalities provided by Diameter protocol as a AAA protocol applicable at the discussed interface. Tschofenig, et al. Expires January 12, 2006 [Page 3] Internet-Draft AAA-HA interface in Mobile IPv6 July 2005 2. Motivation Designed to cover network access requirements for AAA protocols [1], Diameter protocol provides a framework for applications offering AAA services. This design approach gives to the protocol extensibility, interoperability and flexibility in offering AAA solutions in comparison to other AAA protocols. Support of definition of new application Ids, commands and AVPs provides extensibility. Recommended re-use of commands and AVPs and careful consideration of the level of AVP's support provides interoperability. Usage of IPsec and TLS for transport hop-by-hop security, possible support for AVP integrity and confidentiality and usage of peer-to-peer model (any Diameter node can initiate a request message) provide flexibility of the Diameter AAA applications to fit to specific requirements. In the following sections we try to specify by which means a possible Diameter application would cover the requirements for the AAA-HA interface specified in [3]. Tschofenig, et al. Expires January 12, 2006 [Page 4] Internet-Draft AAA-HA interface in Mobile IPv6 July 2005 3. Goals In presentation of the analysis of goals and possible design solutions by Diameter we follow the classification, labels and naming assigned in the document [3], where these goals are identified. Since several of the issues might be addressed in similar way or by similar Diameter functionality, we have grouped these issues and have given a general description of the groups. 3.1 General goals 3.1.1 G1.1 - G1.4 Security As design goals for an AAA interface, G1.1 - G1.4 goals specify standard requirements for a AAA protocol - mutual authentication of the peers, integrity, replay protection and confidentiality. Various authentication methods might be used, many of them are already supported by a Diameter NASREQ and EAP applications [4],[5] and could be re-used. IPsec or TLS provide the hop-by-hop security. Combined, they should be able to provide the range of security services required for the AAA-HA interface. 3.1.2 Dead peer detection - the AAA-HA interface should support inactive peer detection. Two possible approaches might be considered here: o AAAH server and Home Agent establish a transport connection between each other. In this case Diameter heartbeat messages called Watch-Dog-Request/Answer, which are exchanged over this connection to test for its aliveness, may be used to detect inactivity in any of the two Diameter peers. o AAAH server and Home Agent do not have transport connection. In this case inactive peer detection functionality should be provided into the Diameter session - service stateless Diameter sessions might be established between the AAAH server and the range of MSP's Home Agents for detecting HAs availability. 3.2 Service Authorization 3.2.1 G2.1. The AAA-HA interface should allow the use of Network Access Identifier (NAI) to identify the mobile node. Identification by User-Name AVP [1], which has a format consistent Tschofenig, et al. Expires January 12, 2006 [Page 5] Internet-Draft AAA-HA interface in Mobile IPv6 July 2005 with the NAI specifications, is common for Diameter applications. Diameter provides functionality for routing of Diameter requests based on the information included in the User-Name AVP. 3.2.2 G2.2. The HA should be able to query the AAAH server to verify Mobile IPv6 service authorization for the mobile node. Based on the peer-to-peer model, Diameter design gives the functionality that any Diameter node can initiate a request message. This, combined with the support of EAP, would provide flexible solutions for this issue. Currently several Diameter application standardized or under work-in-progress address different types of authorization - network access [4], credit control [6], quality of service [7]. This might allow re-use of present AVPs over the AAAH-HA interface. 3.2.3 G2.3. The AAAH server should be able to enforce explicit operational limitations and authorization restrictions on the HA.( e.g. packet filters, QoS parameters). Several present Diameter applications, standardized or under work-in- progress address an operation and authorization control over specific services and have defined appropriate AVPs. NAS-Filter-Rule AVP, defined by Diameter NASREQ application [4], provides IP packet filter description. QoS-Filter-Rule AVP defined by Diameter NASREQ application and QSPEC AVP defined by Diameter QoS Authorization [7] provide QoS parameter description. Credit Control application [6] provides cost control over requested services. AVPs may be re-used for providing required functionality over the AAAH-HA interface. This, combined with the possibility that any node can initiate request message, gives control to the AAAH server over HA's functionality. 3.2.4 G2.4 - G2.6. Issues addressing the maintenance of a Mobile IPv6 session by the AAAH server, e.g. authorization lifetime, extension of the authorization lifetime and explicit session termination by the AAAH server side. Diameter base protocol provides a powerful set of commands and AVPs for management of the authorization and accounting sessions. A number of AVPs (Auth-Lifetime-AVP, Grace-Period-AVP, Session-Timeout- AVP) handle the duration (in time) of an authorization session [1]. Additional AVPs for measuring the authorization duration in units different that time are specified too [6]. Exchanging of application specific authorization request/answer messages provides extension of the authorization session. Initiation of the re-authorization by both sides could be supported. Both sides could initiate session termination, by using Diameter Session Termination and Abort Session Tschofenig, et al. Expires January 12, 2006 [Page 6] Internet-Draft AAA-HA interface in Mobile IPv6 July 2005 messages. All these are applied to the Diameter session used for authorization of a Mobile IPv6 session and need to be applied appropriately to this Mobile IPv6 session too. 3.2.5 G2.7. The AAAH server should be able to retrieve the Mobile IPv6 state associated to a specific MN from the correspondent HA. This may be useful to periodically verify the Mobile IPv6 service status. This issue has two sides: 1. How the AAAH should know which HA to contact to retrieve current status of MN's Mobile IPv6 service in case of stateless MSP architecture and several servicing AAA servers? - As analyzed into the [8], this need would be required for re-authorization and in this case the provision of HA info could be provided from the MN during the re-authentication session between NM and AAAH server. 2. Once having the HA info, AAAH should contact it to verify the status of MN's Mobile IPv6 service. - This could be performed by Request/Response messages initiated by the AAAH server. This functionality is supported by the Diameter protocol and currently is applied into Diameter SIP application for updating user profiles at Diameter client (i.e., SIP server). 3.3 Accounting - G3.1. The AAA-HA interface must support the transfer of accounting records needed for service control and charging Diameter accounting protocol provides a variety of options - real- time accounting, event/session-type accounting records, fault resilience, correlation of accounting records. Requirements for the accounting services over AAAH-HA interface are standard. Definition or re-used of AVPs for the specific accounting records combined with the functionality of the Diameter accounting protocol should provide desired accounting services. 3.4 Mobile Node Authentication (G4.1. and G4.2.) These issues require the functionality of AAAH server working as a back-end authentication server and HA working as NAS and EAP authenticator in pass-through mode for providing a mobile node authentication. These functionalities are provided by Diameter Tschofenig, et al. Expires January 12, 2006 [Page 7] Internet-Draft AAA-HA interface in Mobile IPv6 July 2005 NASREQ and EAP applications, and might be re-used at the AAAH-AH interface.[4], [5] 3.5 Provisioning of configuration parameters Issues G5.1 - G5.3 are related to capability of exchanging and negotiating of operational parameters for Mobile IPv6 protocol bootstrapping and providing appropriate security level for this information. Diameter provides secure transport by means of IPsec, TLS and possible AVPs integrity and confidentiality support (currently with no interest from the community). Several AVPs could be re-used for carrying the operational parameters for the Mobile IPv6 bootstrapping. Framed-IPv6-Prefix AVP, Login-IPv6-Host AVP, Framed- Interface-Id AVP, Framed-IPv6-Route AVP defined by NASREQ might be used for home address provision and AVPs defined in EAP application might be used for key transport [5]. Tschofenig, et al. Expires January 12, 2006 [Page 8] Internet-Draft AAA-HA interface in Mobile IPv6 July 2005 4. Conclusion This document provides information about the Diameter usage for the AAA-HA interface. It is not yet complete since (a) the goals for the AAA-HA interface [3] are still work in progress and (b) solutions for all scenarios are not yet available. A final conclusion about the required AVPs cannot be provided at this point in time. Tschofenig, et al. Expires January 12, 2006 [Page 9] Internet-Draft AAA-HA interface in Mobile IPv6 July 2005 5. Security considerations [Editor's Note: Since the document is not complete it is necessary to state that the security consideration section is incomplete as well. Hence, it is only possible to refer to the security issues raised in the Mobile IPv6 and Diameter protocol related documents mentioned here, such as [8], [3] and [1].] Tschofenig, et al. Expires January 12, 2006 [Page 10] Internet-Draft AAA-HA interface in Mobile IPv6 July 2005 6. IANA Considerations This document does not require actions to be taken by the IANA. Tschofenig, et al. Expires January 12, 2006 [Page 11] Internet-Draft AAA-HA interface in Mobile IPv6 July 2005 7. Acknowledgements We would like to thank the MIPv6 Bootstrapping Design Team for their comments. Additionally, we would to thank Junghoon Jee for his feedback. Tschofenig, et al. Expires January 12, 2006 [Page 12] Internet-Draft AAA-HA interface in Mobile IPv6 July 2005 8. References 8.1 Normative References [1] Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J. Arkko, "Diameter Base Protocol", RFC 3588, September 2003. [2] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", March 1997. 8.2 Informative References [3] Giaretta, G., "Goals for AAA-HA interface", draft-ietf-mip6-aaa-ha-goals-00 (work in progress), May 2005. [4] Calhoun, P., Zorn, G., Spence, D., and D. Mitton, "Diameter Network Access Server Application", draft-ietf-aaa-diameter-nasreq-17 (work in progress), July 2004. [5] Eronen, P., Hiller, T., and G. Zorn, "Diameter Extensible Authentication Protocol (EAP) Application", draft-ietf-aaa-eap-10 (work in progress), November 2004. [6] Mattila, L., Koskinen, J., Stura, M., Loughney, J., and H. Hakala, "Diameter Credit-control Application", draft-ietf-aaa-diameter-cc-06 (work in progress), August 2004. [7] Alfano, F., "Diameter Quality of Service Application", draft-alfano-aaa-qosprot-02 (work in progress), February 2005. [8] Giaretta, G., "MIPv6 Authorization and Configuration based on EAP", draft-giaretta-mip6-authorization-eap-02 (work in progress), October 2004. [9] Garcia-Martin, M., "Diameter Session Initiation Protocol (SIP) Application", draft-ietf-aaa-diameter-sip-app-07 (work in progress), March 2005. Tschofenig, et al. Expires January 12, 2006 [Page 13] Internet-Draft AAA-HA interface in Mobile IPv6 July 2005 Authors' Addresses Hannes Tschofenig Siemens Otto-Hahn-Ring 6 Munich, Bavaria 81739 Germany Email: Hannes.Tschofenig@siemens.com Tseno Tsenov Siemens Otto-Hahn-Ring 6 Munich, Bayern 81739 Germany Email: tseno.tsenov@mytum.de Gerardo Giaretta Telecom Italia Lab via G. Reiss Romoli, 274 TORINO, 10148 Italy Email: gerardo.giaretta@tilab.com Julien Bournelle GET/INT 9 rue Charles Fourier Evry 91011 France Email: julien.bournelle@int-evry.fr Tschofenig, et al. 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Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Tschofenig, et al. Expires January 12, 2006 [Page 15]