Network Working Group K. Chowdhury, Editor Internet-Draft Starent Networks Intended status: Standards Track A. Yegin Expires: October 22, 2008 Samsung AIT April 20, 2008 MIP6-bootstrapping for the Integrated Scenario draft-ietf-mip6-bootstrapping-integrated-06.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 October 22, 2008. Chowdhury, Editor & Yegin Expires October 22, 2008 [Page 1] Internet-Draft April 2008 Abstract Mobile IPv6 bootstrapping can be categorized into two primary scenarios, the split scenario and the integrated scenario. In the split scenario, the mobile node's mobility service is authorized by a different service authorizer than the network access authorizer. In the integrated scenario, the mobile node's mobility service is authorized by the same service authorizer as the network access service authorizer. This document defines a method for home agent information discovery for the integrated scenario. Table of Contents 1. Introduction and Scope . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Assumptions & Conformance . . . . . . . . . . . . . . . . . . 5 4. Solution Overview . . . . . . . . . . . . . . . . . . . . . . 6 4.1. Logical View of the Integrated Scenario . . . . . . . . . 6 4.2. Bootstrapping Message Sequence . . . . . . . . . . . . . . 7 4.2.1. Home Agent allocation in the MSP . . . . . . . . . . . 8 4.2.2. Home Agent allocation in the ASP . . . . . . . . . . . 9 4.3. Bootstrapping Message Sequence: Fallback case . . . . . . 10 4.4. HoA and IKEv2 SA Bootstrapping in the Integrated Scenario . . . . . . . . . . . . . . . . . . . . . . . . . 11 5. Security Considerations . . . . . . . . . . . . . . . . . . . 12 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 15 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16 9.1. Normative References . . . . . . . . . . . . . . . . . . . 16 9.2. Informative References . . . . . . . . . . . . . . . . . . 16 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18 Intellectual Property and Copyright Statements . . . . . . . . . . 19 Chowdhury, Editor & Yegin Expires October 22, 2008 [Page 2] Internet-Draft April 2008 1. Introduction and Scope The Mobile IPv6 protocol [RFC3775] requires the mobile node to have information of its Home Address, the home agent address and the cryptographic materials for establishing an IPsec security association with the home agent prior to initiating the registration process. The mechanism via which the mobile node obtains these information is called Mobile IPv6 bootstrapping. In order to allow a flexible deployment model for Mobile IPv6, it is desirable to define a bootstrapping mechanism for the mobile node to acquire these parameters dynamically. [RFC4640] describes the problem statement for Mobile IPv6 bootstrapping. It also defines the bootstrapping scenarios based on the relationship between the entity that authenticates and authorizes the mobile node for network access (i.e., the Access Service Authorizer) and the entity that authenticates and authorizes the mobile node for mobility service (i.e., the Mobility Service Authorizer). The scenario in which the Access Service Authorizer is not the Mobility Service Authorizer is called the "Split" scenario. The bootstrapping solution for the split scenario is defined in [RFC5026]. The scenario in which the Access Service Authorizer is also the Mobility Service Authorizer is called the "Integrated" scenario. This document defines a bootstrapping solution for the Integrated scenario. [RFC5026] identifies four different components of the bootstrapping problem: home agent address discovery, HoA assignment, IPsec Security Association [RFC4301] setup, and Authentication and Authorization with the MSA. This document defines a mechanism for home agent address discovery. The other components of bootstrapping are as per [RFC5026]. In the integrated scenario, the bootstrapping of the home agent information can be achieved via DHCPv6. This document defines the MIPv6 bootstrapping procedures for the integrated scenario. It enables Home Agent assignment in the integrated scenario by utilizing DHCP and AAA protocols. The specification utilizes DHCP and AAA options and AVPs that are defined in [HIOPT], [MIP6-Dime], and [MIP6-RADIUS]. This document specifies the interworking among MN, NAS, DHCP, and AAA entities for the bootstrapping procedure in the integrated scenario. Chowdhury, Editor & Yegin Expires October 22, 2008 [Page 3] Internet-Draft April 2008 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. General mobility terminology can be found in [RFC3753]. The following additional terms, as defined in [RFC4640], are used in this document: Access Service Authorizer (ASA): A network operator that authenticates a mobile node and establishes the mobile node's authorization to receive Internet service. Access Service Provider (ASP): A network operator that provides direct IP packet forwarding to and from the mobile node. Mobility Service Authorizer (MSA): A service provider that authorizes Mobile IPv6 service. Mobility Service Provider (MSP): A service provider that provides Mobile IPv6 service. A MSP is called home MSP when MSP == MSA. In this document the term MSP means a Mobility Service Provider that has roaming relationship with the MSA but it is not the MSA. Split scenario: A scenario where the mobility service and the network access service are authorized by different entities. Integrated Scenario: A scenario where the mobility service and the network access service are authorized by the same entity. Chowdhury, Editor & Yegin Expires October 22, 2008 [Page 4] Internet-Draft April 2008 3. Assumptions & Conformance The following assumptions are made in this document: a. MSA == ASA. b. MSA and MSP roaming relationship is assumed but not required. c. DHCP relay and NAS are co-located or there is a mechanism to transfer received AAA information from the NAS to the DHCP relay. Note: If assignment of a home agent in the home MSP is not required by a deployment, co-location of the NAS and the DHCP relay functions or a mechanism to transfer received AAA information from the NAS to the DHCP relay won't be necessary. In such a case, only the implementation of the options and procedures defined in [HIOPT] should suffice. d. The NAS shall support MIPv6 specific AAA attributes as specified in [MIP6-RADIUS] and [MIP6-Dime]. e. The AAAH used for network access authentication (ASA) has access to the same database as the AAAH used for the mobility service authentication (MSA). If home agent assignment only in the ASP is required by the deployment, a minimal implementation of this specification MAY only support the delivery of information from the DHCP server to the DHCP client through [HIOPT]. However, if home agent assignment in the MSP is required by the deployment, an implementation conforming to this specification SHALL be able to transfer received information (from the AAA server) from the NAS to the DHCP relay function. This can be achieved either by co-locating the NAS and the DHCP relay functions or via an interface between these functions. The detail of this interface is out of scope of this specification. Chowdhury, Editor & Yegin Expires October 22, 2008 [Page 5] Internet-Draft April 2008 4. Solution Overview 4.1. Logical View of the Integrated Scenario In the integrated scenario, the mobile node utilizes the network access authentication process to bootstrap Mobile IPv6. It is assumed that the access service authorizer is mobility service aware. This allows for Mobile IPv6 bootstrapping at the time of access authentication and authorization. Also, the mechanism defined in this document requires the NAS to support Mobile IPv6 specific AAA attributes and a co-located DHCP relay agent. The following diagram shows the network elements and layout in the integrated scenario: | ASP(/MSP) | ASA/MSA(/MSP) | | +-------+ | +-------+ | | | | | |AAAV |-----------|--------|AAAH | | | | | | +-------+ | +-------+ | | | | | | | | +-----+ +------+ | +----+ | NAS/| |DHCP | | | MN |------|DHCP |----|Server| | +----+ |Relay| | | | +-----+ +------+ | | | +--------+ | +--------+ | HA | | | HA | | in ASP | | |in MSP | +--------+ | +--------+ Figure 1. Integrated Scenario, Network Diagram with DHCP Server Figure 1 shows the AAA infrastructure with an AAA client (NAS), an AAA proxy in the visited network and an AAA server in the home Chowdhury, Editor & Yegin Expires October 22, 2008 [Page 6] Internet-Draft April 2008 network. The user's home network authorizes the mobile node for network access and also for mobility services. Note that a home agent for usage with the mobile node might be selected in the access service provider's network or alternatively in the mobility service provider's network. The mobile node interacts with the DHCP Server via the Relay Agent after the network access authentication as part of the mobile node configuration procedure. 4.2. Bootstrapping Message Sequence In this case, the mobile node is able to acquire the home agent address via a DHCPv6 query. The message flows for home agent allocation in the ASP and the MSP are illustrated below. In the integrated scenario, the ASA and the MSA are the same, it can be safely assumed that the AAAH used for network access authentication (ASA) has access to the same database as the AAAH used for the mobility service authentication (MSA). Hence, the same AAAH can authorize the mobile node for network access and mobility service at the same time. When the MN performs Mobile IPv6 registration, the AAAH ensures that the MN is accessing the assigned Home Agent for that MSP. Figure 2 shows the message sequence for home agent allocation in both scenarios -- HA in the MSP, and HA in the ASP. Chowdhury, Editor & Yegin Expires October 22, 2008 [Page 7] Internet-Draft April 2008 | --------------ASP------>|<--ASA+MSA-- | +----+ +------+ +-------+ +-----+ | | | | | | | | | MN/| |NAS/ | | DHCP | |AAAH | |User| |DHCP | | Server| | | | | |relay | | | | | +----+ +------+ +-------+ +-----+ | | | | | 1 | 1 | | |<------------->|<---------------------->| | | | | | | | | | 2 | | | |-------------->| | | | | | | | | 3 | | | |------------>| | | | | | | | 4 | | | |<------------| | | | | | | 5 | | | |<--------------| | | | | | | Figure 2. Message sequence for Home Agent allocation 4.2.1. Home Agent allocation in the MSP This section describes a scenario where the home agent is allocated in the mobile node's MSP network(s). In order to provide the mobile node with information about the assigned home agent, the AAAH conveys the assigned home agent's information to the NAS via an AAA protocol, e.g., [MIP6-RADIUS] or [MIP6-Dime]. Figure 2 shows the message sequence for home agent allocation. In the scenario with HA in the MSP, the following details apply. (1) The mobile node executes the network access authentication procedure (e.g., IEEE 802.11i/802.1X) and it interacts with the NAS. The NAS is in the ASP and it interacts with the AAAH, which is in the ASA/MSA, to authenticate the mobile node. In the process of authorizing the mobile node, the AAAH verifies in the AAA profile that the mobile node is allowed to use the Mobile IPv6 service. The AAAH assigns a home agent in the home MSP and it assigns one or more Chowdhury, Editor & Yegin Expires October 22, 2008 [Page 8] Internet-Draft April 2008 home agent(s) in other authorized MSPs and returns this information to the NAS. The NAS may keep the received information for a configurable duration or it may keep the information for as long as the MN is connected to the NAS. (2) The mobile node sends a DHCPv6 Information Request message [RFC3315] to the All_DHCP_Relay_Agents_and_Servers multicast address. In this message, the mobile node (DHCP client) SHALL include the Option Code for the Home Network Identifier Option [HIOPT] in the OPTION_ORO, and a Home Network Identifier Option with id-type set to 1 and the Home Network Identifier field set to the network realm of the home MSP [HIOPT]. The mobile node SHALL also include the OPTION_CLIENTID to identify itself to the DHCP server. (3) The Relay Agent intercepts the Information Request from the mobile node and forwards it to the DHCP server. The Relay Agent also includes the received home agent information from the AAAH in the OPTION_MIP6-RELAY-Option [HIOPT]. If a NAS implementation does not store the received information as long as the MN's session remains in the ASP, and if the MN delays sending a DHCP request, the NAS/DHCP relay does not include the OPTION_MIP6-RELAY-Option in the Relay Forward message. (4) The DHCP server identifies the client by looking at the DUID for the client in the OPTION_CLIENTID. The DHCP server also determines that the mobile node is requesting home agent information in the MSP by looking at the Home Network Identifier Option (id-type 1). The DHCP server determines that the home agent is allocated by the AAAH by looking at the MIP6 home agent sub-option in the OPTION_MIP6- RELAY-Option. The DHCP server extracts the allocated home agent information from the OPTION_MIP6-RELAY-Option and includes it in the Home Network Information Option [HIOPT] in the Reply Message. If the requested information is not available in the DHCP server, it follows the behavior described in [HIOPT]. (5) The Relay Agent relays the Reply Message from the DHCP server to the mobile node. At this point, the mobile node has the home agent information that it requested. 4.2.2. Home Agent allocation in the ASP This section describes a scenario where the mobile node requests for home agent allocation in the ASP by setting the id-type field to zero in the Home Network Identifier Option [HIOPT] in the DHCPv6 request message. In this scenario, the ASP becomes the MSP for the duration of the network access authentication session. Figure 2 shows the message sequence for home agent allocation. In Chowdhury, Editor & Yegin Expires October 22, 2008 [Page 9] Internet-Draft April 2008 the scenario with HA in the ASP, the following details apply. (1) The mobile node executes the network access authentication procedure (e.g., IEEE 802.11i/802.1X) and it interacts with the NAS. The NAS is in the ASP and it interacts with the AAAH, which is in the ASA/MSA, to authenticate the mobile node. In the process of authorizing the mobile node, the AAAH verifies in the AAA profile that the mobile node is allowed to use the Mobile IPv6 services. The AAAH assigns a home agent in the home MSP and it assigns one or more home agent(s) in other authorized MSPs and returns this information to the NAS. Note that the AAAH is not aware of the fact that the mobile node prefers a home agent allocation in the ASP. Therefore the assigned home agent may not be used by the mobile node. This leaves the location of the mobility anchor point decision to the mobile node. (2) The mobile node sends a DHCPv6 Information Request message [RFC3315] to the All_DHCP_Relay_Agents_and_Servers multicast address. In this message, the mobile node (DHCP client) SHALL include the Option Code for the Home Network Identifier Option [HIOPT] in the OPTION_ORO, and a Home Network Identifier Option with id-type set to 0. The mobile node SHALL also include the OPTION_CLIENTID to identify itself to the DHCP server. (3) The Relay Agent intercepts the Information Request from the mobile node and forwards it to the DHCP server. The Relay Agent (which is the NAS) also includes the received AAA AVP from the AAAH in the OPTION_MIP6-RELAY-Option [HIOPT]. (4) The DHCP server identifies the client by looking at the DUID for the client in the OPTION_CLIENTID. The DHCP server also determines that the mobile node is requesting home agent information in the ASP by looking at the Home Network Identifier Option (id-type 0). If configured to do so, the DHCP server allocates a home agent from its configured list of home agents and includes it in the Home Network Information Option [HIOPT] in the Reply Message. Note that in this case, the DHCP server does not use the received information in the OPTION_MIP6-RELAY-Option. (5) The Relay Agent relays the Reply Message from the DHCP server to the mobile node. At this point, the mobile node has the home agent information that it requested. 4.3. Bootstrapping Message Sequence: Fallback case In the fallback case, the mobile node is not able to acquire the home agent information via DHCPv6. The mobile node MAY perform DNS queries to discover the home agent address as defined in [RFC5026]. Chowdhury, Editor & Yegin Expires October 22, 2008 [Page 10] Internet-Draft April 2008 To perform DNS based home agent discovery, the mobile node needs to know the DNS server address. The details of how the MN is configured with the DNS server address is outside the scope of this document. 4.4. HoA and IKEv2 SA Bootstrapping in the Integrated Scenario In the integrated scenario, the HoA, IPsec Security Association setup, and Authentication and Authorization with the MSA are bootstrapped via the same mechanism as described in the bootstrapping solution for the split scenario [RFC5026]. Chowdhury, Editor & Yegin Expires October 22, 2008 [Page 11] Internet-Draft April 2008 5. Security Considerations The transport of the assigned home agent information via the AAA infrastructure (i.e., from the AAA server to the AAA client) to the NAS may only be integrity protected as per standard RADIUS and Diameter security mechanisms. No additional security considerations are imposed by the usage of this document. The security mechanisms provided by [RFC2865] and [RFC3588] are applicable for this purpose. This document does not introduce any new security issues to Mobile IPv6. Chowdhury, Editor & Yegin Expires October 22, 2008 [Page 12] Internet-Draft April 2008 6. IANA Considerations None Chowdhury, Editor & Yegin Expires October 22, 2008 [Page 13] Internet-Draft April 2008 7. Acknowledgements The authors would like to thank Kilian Weniger, Vidya Narayanan, and George Tsirtsis for their review and comments. Thanks to Alfred Hoenes for thorough review and valuable suggestions to improve the readability of the document. Chowdhury, Editor & Yegin Expires October 22, 2008 [Page 14] Internet-Draft April 2008 8. Contributors This contribution is a joint effort of the bootstrapping solution design team of the MEXT WG. The contributors include Gerardo Giaretta, Basavaraj Patil, Alpesh Patel, Jari Arkko, James Kempf, Gopal Dommety, Alper Yegin, Junghoon Jee, Vijay Devarapalli, Kuntal Chowdhury, Julien Bournelle, and Hannes Tschofenig. The design team members can be reached at: Gerardo Giaretta gerardog@qualcomm.com Basavaraj Patil basavaraj.patil@nsn.com Alpesh Patel alpesh@cisco.com Jari Arkko jari.arkko@kolumbus.fi James Kempf kempf@docomolabs-usa.com Gopal Dommety gdommety@cisco.com Alper Yegin a.yegin@partner.samsung.com Junghoon Jee jhjee@etri.re.kr Vijay Devarapalli Vijay.Devarapalli@AzaireNet.com Kuntal Chowdhury kchowdhury@starentnetworks.com Julien Bournelle julien.bournelle@orange-ftgroup.com Hannes Tschofenig hannes.tschofenig@nsn.com Chowdhury, Editor & Yegin Expires October 22, 2008 [Page 15] Internet-Draft April 2008 9. References 9.1. Normative References [HIOPT] Hee Jang et. al., A., "DHCP Option for Home Agent Discovery in MIPv6.", draft-ietf-mip6-hiopt-15.txt (work in progress), April 2008. [MIP6-Dime] Korhonen et. al., J., "Diameter Mobile IPv6: NAS - HAAA Support.", draft-ietf-dime-mip6-integrated-04.txt (work in progress), May 2007. [MIP6-RADIUS] Lior et. al., A., "RADIUS Mobile IPv6 Support.", draft-ietf-mip6-radius-03.txt (work in progress), November 2007. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson, "Remote Authentication Dial In User Service (RADIUS)", RFC 2865, June 2000. [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., and M. Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3315, July 2003. [RFC3588] Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J. Arkko, "Diameter Base Protocol", RFC 3588, September 2003. [RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in IPv6", RFC 3775, June 2004. [RFC5026] Giaretta, G., Kempf, J., and V. Devarapalli, "Mobile IPv6 Bootstrapping in Split Scenario", RFC 5026, October 2007. 9.2. Informative References [RFC3753] Manner, J. and M. Kojo, "Mobility Related Terminology", RFC 3753, June 2004. [RFC4301] Kent, S. and K. Seo, "Security Architecture for the Internet Protocol", RFC 4301, December 2005. [RFC4640] Patel, A. and G. Giaretta, "Problem Statement for bootstrapping Mobile IPv6 (MIPv6)", RFC 4640, Chowdhury, Editor & Yegin Expires October 22, 2008 [Page 16] Internet-Draft April 2008 September 2006. Chowdhury, Editor & Yegin Expires October 22, 2008 [Page 17] Internet-Draft April 2008 Authors' Addresses Kuntal Chowdhury Starent Networks 30 International Place Tewksbury, MA 01876 US Email: kchowdhury@starentnetworks.com Alper Yegin Samsung AIT Istanbul, Turkey Email: a.yegin@partner.samsung.com Chowdhury, Editor & Yegin Expires October 22, 2008 [Page 18] Internet-Draft April 2008 Full Copyright Statement Copyright (C) The IETF Trust (2008). 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. 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Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat 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 implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. 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. Chowdhury, Editor & Yegin Expires October 22, 2008 [Page 19]