MIP6 Working Group V. Devarapalli Internet-Draft Nokia Expires: April 18, 2005 October 18, 2004 Mobile IPv6 Operation with IKEv2 and the revised IPsec Architecture draft-ietf-mip6-ikev2-ipsec-00.txt Status of this Memo This document is an Internet-Draft and is subject to all provisions of section 3 of RFC 3667. 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 become aware will be disclosed, in accordance with RFC 3668. 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 April 18, 2005. Copyright Notice Copyright (C) The Internet Society (2004). Abstract This document describes Mobile IPv6 operation with the revised IPsec architecture and IKEv2. Devarapalli Expires April 18, 2005 [Page 1] Internet-Draft Mobile IPv6 with IKEv2 and revised IPsec October 2004 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. What is applicavble from RFC 3776? . . . . . . . . . . . . . . 5 3.1 Packet Formats . . . . . . . . . . . . . . . . . . . . . . 5 3.2 Requirements . . . . . . . . . . . . . . . . . . . . . . . 5 3.2.1 Home Agent Requirements . . . . . . . . . . . . . . . 5 3.2.2 Mobile Node Requirements . . . . . . . . . . . . . . . 6 4. Manual Configuration . . . . . . . . . . . . . . . . . . . . . 7 4.1 Binding Update and Acknowledgements . . . . . . . . . . . 7 4.2 Return Routabililty Messages . . . . . . . . . . . . . . . 8 4.3 Mobile Prefix Discovery Messages . . . . . . . . . . . . . 8 4.4 Payload Packets . . . . . . . . . . . . . . . . . . . . . 9 5. Dynamic Configuration . . . . . . . . . . . . . . . . . . . . 10 5.1 Security Policy Database Entries . . . . . . . . . . . . . 10 5.1.1 Binding Updates and Acknowledgements . . . . . . . . . 10 5.1.2 Return Routability Messages . . . . . . . . . . . . . 11 5.1.3 Mobile Prefix Discovery Messages . . . . . . . . . . . 11 5.1.4 Payload Packets . . . . . . . . . . . . . . . . . . . 12 5.2 Security Association negotiation using IKEv2 . . . . . . . 12 6. The use of EAP authentication . . . . . . . . . . . . . . . . 14 7. Dynamic Home Address Configuration . . . . . . . . . . . . . . 15 8. Security Considerations . . . . . . . . . . . . . . . . . . . 16 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 18 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 19 11.1 Normative References . . . . . . . . . . . . . . . . . . . . 19 11.2 Informative References . . . . . . . . . . . . . . . . . . . 19 Author's Address . . . . . . . . . . . . . . . . . . . . . . . 20 Intellectual Property and Copyright Statements . . . . . . . . 21 Devarapalli Expires April 18, 2005 [Page 2] Internet-Draft Mobile IPv6 with IKEv2 and revised IPsec October 2004 1. Introduction RFC 3776 describes how IPsec [7] is used with Mobile IPv6 [2] to protect the signaling messages. It also illustrates the Security Policy Database and Security Association Database entries required to protect Mobile IPv6 signaling messages. The IPsec architecture has been revised [5]. Among the many changes, the list of selectors has been expanded to included the Mobility Header message type. This has an impact on how security policies and security associations are configured for protecting mobility header messages. It becomes easier to differentiate between the various Mobility Header messages based on the type value instead of checking if a particular mobility header message is being sent on a tunnel interface between the MN and the HA, as it was in RFC 3776. The revised IPsec architecture specification also includes ICMP message type and code as selectors. This makes it possible to protect Mobile Prefix Discovery messages without applying the same security associations to all ICMPv6 messages. This document discusses new requirements for the Home Agent and the Mobile Node to use the revised IPsec architecture and IKEv2. Section 3.2 lists the requirements. Section 3 describes the differences with RFC 3776. Section 4 describes the required Security Policy Database (SPD) and Security Association Database (SAD) entries. The Internet Key Exchange (IKE) has also been substantially revised and simplified [4]. This document describes how IKEv2 can be used to setup security associations for Mobile IPv6. The use of EAP within IKEv2 is allowed to authenticate the Mobile Node to the Home Agent. This is described in Section 6. A method for dynamically configuring a Home Address from the Home Agent using the Configuration Payload in IKEv2 is described in Section 7. Devarapalli Expires April 18, 2005 [Page 3] Internet-Draft Mobile IPv6 with IKEv2 and revised IPsec October 2004 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 [1]. Devarapalli Expires April 18, 2005 [Page 4] Internet-Draft Mobile IPv6 with IKEv2 and revised IPsec October 2004 3. What is applicavble from RFC 3776? 3.1 Packet Formats The Mobile Node and the Home Agent MUST support the packet formats as defined in Seciton 3 of RFC 3776. 3.2 Requirements The Mobile Node and the Home Agent MUST support the requirements listed in Section 4 of RFC 3776 with the following exceptions. o It is not required to configure security policies per interface in order to protect return routability signaling messages. Since the Mobility Header message type is a selector, it is easy to differentiate HoTi and HoT messages from other Mobility Header messages. o It is necessary to avoid a condition where a mobile ndoe could use its security association to send a Binding Update on behalf of another Mobile Node. With manual IPsec configuration, the Home Agent MUST be able to verify that a security association was created for a particular Home Address. With dynamic keying, it should be possible for the Home Agent to verify that the identity presented in the IKE_AUTH exchange is allowed to create security associations for a particular home address. o The Mobile Node should use its Care-of Address as source address in protocol exchanges, when using dynamic keying. However, the security associations MUST be created for the Home Address of the Mobile Node. o The Mobile Node and the Home Agent MUST create security associations based on the Home Address, so that the security associations survive change in Care-of Address. When using IKEv2 as the key exchange protocol, the TSi payload during the CREATE_CHILD_SA exchange [4] MUST carry the Home Address of the Mobile Node. 3.2.1 Home Agent Requirements This section describes some new and additional requirements on the Home Agent. o The Home Agent MUST support Mobility Header message type as an IPsec selector. Devarapalli Expires April 18, 2005 [Page 5] Internet-Draft Mobile IPv6 with IKEv2 and revised IPsec October 2004 o The Home Agent MUST support ICMPv6 message type as an IPsec selector. o The Home Agent MUST be able to distinguish between HoTi messages sent to itself, when it is acting as a Correspondent Node) from those sent to Correspondent Nodes when it is acting as a Home Agent, based on the destination address of the packet. o The Home Agent MUST have an entry for each Mobile Node in its Peer Authorization Database (PAD), [5]. The PAD entry for a Mobile Node contains either a shared key or a trust anchor to verify the Mobile Node's certificate. o The Home Agent MUST support remote configuration of Home Address as descrined in Section 7. When the Home Agent receives a configuration payload with a CFG_REQUEST for INTERNAL_IP6_ADDR, it must reply with a valid Home Address for the Mobile Node. The Home Agent could pick a Home Address from a local database or from a DHCPv6 server on the home link. o The Home Agent MAY support authentication using EAP in IKEv2 as described in Section 2.16 of [4]. 3.2.2 Mobile Node Requirements This section describes new additional requirements on the Mobile Node. o The Mobile Node MUST support Mobility Header message type as an IPsec selector. o The Mobile Node MUST supprt ICMPv6 message type as an IPsec selector. o The Mobile Node MAY support EAP as an authentication mechanism when using IKEv2 to setup security associations for protecting Mobile IPv6 signaling messages. o The Mobile Node MAY support the mechanism described in Section 7 to dynamically configure a Home Address. Devarapalli Expires April 18, 2005 [Page 6] Internet-Draft Mobile IPv6 with IKEv2 and revised IPsec October 2004 4. Manual Configuration This section describes the SPD and SAD entries necessary to protect the Mobile IPv6 signaling messages. The format used to describe the SPD and SAD entries is the same as described in RFC 3776. For the examples described in this document, a Mobile Node with home address, "home_address_1", a Home Agent with addres, "home_agent_1" and a user of the Mobile Node with identity "user_1" are assumed. 4.1 Binding Update and Acknowledgements mobile node SPD-S: - IF source = home_address_1 & destination = home_agent_1 & proto = MH & mh_type = BU THEN USE SA SA1 mobile node SPD-I: - IF source = home_agent_1 & destination = home_address_1 & proto = MH & mh_type = BAck THEN USE SA SA2 mobile node SAD: - SA1(OUT, spi_a, home_agent_1, ESP, TRANSPORT): source = home_address_1 & destination = home_agent_1 & proto = MH & mh_type = BU - SA2(IN, spi_b, home_address_1, ESP, TRANSPORT): source = home_agent_1 & destination = home_address_1 & proto = MH & mh_type = BAck home agent SPD-S: - IF source = home_agent_1 & destination = home_address_1 & proto = MH & mh_type = BAck THEN USE SA SA2 home agent SPD-I: - IF source = home_address_1 & destination = home_agent_1 & proto = MH & mh_type = BU THEN USE SA SA1 home agent SAD: - SA2(OUT, spi_b, home_address_1, ESP, TRANSPORT): source = home_agent_1 & destination = home_address_1 & proto = MH & mh_type = BAck - SA1(IN, spi_a, home_agent_1, ESP, TRANSPORT): source = home_address_1 & destination = home_agent_1 & proto = MH & mh_type = BU Devarapalli Expires April 18, 2005 [Page 7] Internet-Draft Mobile IPv6 with IKEv2 and revised IPsec October 2004 4.2 Return Routabililty Messages mobile node SPD-S: - IF source = home_address_1 & destination = any & proto = MH & mh_type = HoTi THEN USE SA SA3 mobile node SPD-I: - IF destination = home_address_1 & source = any & proto = MH & mh_type = HoT THEN USE SA SA4 mobile node SAD: - SA3(OUT, spi_c, home_agent_1, ESP, TUNNEL): source = home_address_1 & destination = any & proto = MH & mh_type = HoTi - SA4(IN, spi_d, care_of_address_1, ESP, TUNNEL): source = any & destination = home_address_1 & proto = MH & mh_type = HoT home agent SPD-S: - IF destination = home_address_1 & source = any & proto = MH & mh_type = HoT THEN USE SA SA4 home agent SPD-I: - IF source = home_address_1 & destination = any & proto = MH & mh_type = HoTi THEN USE SA SA3 home agent SAD: - SA4(OUT, spi_d, care_of_address_1, ESP, TUNNEL): source = any & destination = home_address_1 & proto = MH & mh_type = HoT - SA3(IN, spi_c, home_agent_1, ESP, TUNNEL): source = home_address_1 & destination = any & proto = MH & mh_type = HoTi 4.3 Mobile Prefix Discovery Messages Devarapalli Expires April 18, 2005 [Page 8] Internet-Draft Mobile IPv6 with IKEv2 and revised IPsec October 2004 mobile node SPD-S: - IF source = home_address_1 & destination = home_agent_1 & proto = ICMPv6 & icmp6_type = MPS THEN USE SA SA5. mobile node SPD-I: - IF source = home_agent_1 & destination = home_address_1 & proto = ICMPv6 & icmp6_type = MPA THEN USE SA SA6 mobile node SAD: - SA5(OUT, spi_e, home_agent_1, ESP, TRANSPORT): source = home_address_1 & destination = home_agent_1 & proto = ICMPv6 & icmp6_type = MPS - SA6(IN, spi_f, home_address_1, ESP, TRANSPORT): source = home_agent_1 & destination = home_address_1 & proto = ICMPv6 & icmp6_type = MPA home agent SPD-S: - IF source = home_agent_1 & destination = home_address_1 & proto = ICMPv6 & icmp6_type = MPA THEN USE SA SA6 home agent SPD-I: - IF source = home_address_1 & destination = home_agent_1 & proto = ICMPv6 & icmp6_type = MPS THEN USE SA SA5 home agent SAD: - SA6(OUT, spi_f, home_address_1, ESP, TRANSPORT): source = home_agent_1 & destination = home_address_1 & proto = ICMPv6 & icmp6_type = MPA - SA5(IN, spi_e, home_agent_1, ESP, TRANSPORT): source = home_address_1 & destination = home_agent_1 & proto = ICMPv6 & icmp6_type = MPS 4.4 Payload Packets Payload traffic tunneled through the Home Agent can be protected by IPsec, if required. The Mobile Node and the Home Agent use ESP in tunnel mode to protect the tunneled traffic. The SPD and SAD entries shown in Section 5.2.4 of [3] are applicable here. Devarapalli Expires April 18, 2005 [Page 9] Internet-Draft Mobile IPv6 with IKEv2 and revised IPsec October 2004 5. Dynamic Configuration This section describes the use of IKEv2 to setup the required security associatiosn. 5.1 Security Policy Database Entries 5.1.1 Binding Updates and Acknowledgements mobile node SPD-S: - IF destination = home_agent_1 & proto = MH & mh_type = BU THEN USE SA ESP TRANSPORT: local identity = user_1 mobile node SPD-I: - IF source = home_agent_1 & proto = MH & mh_type = BAck THEN USE SA ESP TRANSPORT: local identity = user_1 home agent SPD-S: - IF source = home_agent_1 & proto = MH & mh_type = BAck THEN USE SA ESP TRANSPORT: peer identity = user_1 home agent SPD-I: - IF destination = home_agent_1 & proto = MH & mh_type = BU THEN USE SA ESP TRANSPORT: peer identity = user_1 Devarapalli Expires April 18, 2005 [Page 10] Internet-Draft Mobile IPv6 with IKEv2 and revised IPsec October 2004 5.1.2 Return Routability Messages mobile node SPD-S: - IF proto = MH & mh_type = HoTi THEN USE SA ESP TUNNEL: outer destination = home_agent_1 & local identity = user_1 & inner source address =home_address_1 mobile node SPD-I: - IF source = any & destination = home_address_1 & proto = MH & mh_type = HoT THEN USE SA ESP TUNNEL: outer destination = home_agent_1 & local identity = user_1 home agent SPD-S: - IF source = any & destination = home_address_1 & proto = MH & mh_type = HoT THEN USE SA ESP TUNNEL: inner destination = home_address_1 & peer identity = user_1 home agent SPD-I: - IF source = home_address_1 & destination = any & proto = MH & mh_type = HoTi THEN USE SA ESP TUNNEL: inner destination = home_address_1 & peer identity = user_1 5.1.3 Mobile Prefix Discovery Messages mobile node SPD-S: - IF destination = home_agent_1 & proto = ICMPv6 & icmp6_type = MPS THEN USE SA ESP TRANSPORT: local identity = user_1 mobile node SPD-I: - IF source = home_agent_1 & proto = ICMPv6 & icmp6_type = MPA THEN USE SA ESP TRANSPORT: local identity = user_1 home agent SPD-S: - IF source = home_agent_1 & proto = ICMPv6 & icmp6_type = MPA THEN USE SA ESP TRANSPORT: peer identity = user_1 home agent SPD-I: - IF destination = home_agent_1 & proto = ICMPv6 & icmp6_type = MPS THEN USE SA ESP TRANSPORT: peer identity = user_1 Devarapalli Expires April 18, 2005 [Page 11] Internet-Draft Mobile IPv6 with IKEv2 and revised IPsec October 2004 5.1.4 Payload Packets The SPD and SAD entries shown in Section 5.3.4 of [3] are applicable here. This document does not update the SPD and SAD entries described in RFC3776 for protecting payload packets. 5.2 Security Association negotiation using IKEv2 Mobile IPv6 signaling messages are always first initiated by the Mobile Node. The Mobile Node sends a Binding Update to the Home Agent whenever it moves and acquires a new Care-of Address. The Mobile Node initiates an IKEv2 protocol exchange if the required security associations are not present. For authenticating the Home Agent, public key based mechanisms MUST be used. The Mobile Node includes a Certificate Request payload in the first message sent in the IKE_AUTH exchange. If the Mobile Node is using a shared key for authentication, it uses the shared key to generate the AUTH payload in the IKE_AUTH exchange. If the Mobile Node is using a public key based mechanism, then it uses its private key to generate the AUTH payload in the IKE_AUTH exchange. The Mobile Node MUST always includes its identity in the IDi payload in the IKE_AUTH exchange. The Mobile Node could use a FQDN or RFC 822 [13] identifier as identities. In case the Mobile Node uses FQDN, it sets the IDi type to ID_FQDN. In case, the Mobile Nodes uses a RFC 822 kind of identifier, it sets the IDi type to ID_RFC822_ADDR. Mobile Node Home Agent ----------- ---------- HDR, SAi1, KEi, Ni --> <-- HDR, SAr1, KEr, Nr, [CERTREQ] HDR, SK {IDi, [CERT,] [CERTREQ,] [IDr,] AUTH, SAi2, TSi, TSr} --> <-- HDR, SK {IDr, [CERT,] AUTH, SAr2, TSi, TSr} After the IKE_AUTH exchange completes, the Mobile Node and the Home Agent initiate CREATE_CHILD_SA exchanges to negotiate security associations for protecting Binding Update/Binding Ack messages, Return Routability signaling, Mobile Prefix Discovery messages and optionally payload traffic. The CREATE_CHILD_SA exchanges are protected by the security association created during the IKE_AUTH exchange. Devarapalli Expires April 18, 2005 [Page 12] Internet-Draft Mobile IPv6 with IKEv2 and revised IPsec October 2004 It is important that the security associations are created based on the Home Address of the Mobile Node, so that the security associations survive Care-of Address change. The Mobile Node MUST set the TSi (Traffic Selector-initiator) payload to its Home Address in the CREATE_CHILD_SA exchange in order to create the security associations for the Home Address. Mobile Node Home Agent ----------- ---------- HDR, SK {[N], SA, Ni, [KEi], [TSi, TSr]} --> <-- HDR, SK {SA, Nr, [KEr], [TSi, TSr]} Devarapalli Expires April 18, 2005 [Page 13] Internet-Draft Mobile IPv6 with IKEv2 and revised IPsec October 2004 6. The use of EAP authentication In addition to using public key signatures and shared secrets, EAP [14] can be used with IKEv2 for authenticating the Mobile Node to the Home Agent. The Mobile Node indicates that it wants to use EAP by including the IDi payload but leaving out the AUTH payload in the first message during the IKE_AUTH exchange. The Home Agent includes an EAP payload if it is willing to use an extensible authentication method. Security associations are not created until the subsequent IKE_AUTH exchange after successful EAP authentication. Mobile Node Home Agent ------------ ---------- HDR, SAi1, KEi, Ni --> <-- HDR, SAr1, KEr, Nr, [CERTREQ] HDR, SK {IDi, [CERTREQ,] [IDr,] SAi2, TSi, TSr}--> <-- HDR, SK {IDr, [CERT,] AUTH, EAP } HDR, SK {EAP} --> <-- HDR, SK {EAP (success)} HDR, SK {AUTH} --> <-- HDR, SK {AUTH, SAr2, TSi, TSr} Devarapalli Expires April 18, 2005 [Page 14] Internet-Draft Mobile IPv6 with IKEv2 and revised IPsec October 2004 7. Dynamic Home Address Configuration The Mobile Node can dynamically configure a Home Address by including a Configuration Payload with a request for an address from the home link. The Mobile Node MUST include an INTERNAL_IP6_ADDRESS and INTERNAL_IP6_SUBNET attributes in the Configuration Payload. The Mobile Node MAY also include an INTERNAL_IP6_DNS attribute. When the Home Agent receives a configuration payload with a CFG_REQUEST for INTERNAL_IP6_ADDRESS, it replies with a valid Home Address for the Mobile Node. The Home Agent could use a local database or contact a DHCPv6 server on the home link to allocate a Home Address. The Home Agent MUST also include an INTERNAL_ADDRESS_EXPIRY attribute to indicate to the Mobile Node, the duration for which the dynamically allocated Home Address is valid. In case the Home Agent is unable to allocate a Home Address for the Mobile Node during the IKE_AUTH exhcange, it MUST send a Notify Payload with an INTERNAL_ADDRESS_FAILURE message. Mobile Node Home Agent ----------- ---------- HDR, SK {IDi, [CERT,] [CERTREQ,] [IDr,] AUTH, CP(CFG_REQUEST), SAi2, TSi, TSr} --> <-- HDR, SK {IDr, [CERT,] AUTH, CP(CFG_REPLY), SAr2, TSi, TSr} Devarapalli Expires April 18, 2005 [Page 15] Internet-Draft Mobile IPv6 with IKEv2 and revised IPsec October 2004 8. Security Considerations This document describes how IPsec can be used to secure Mobile IPv6 signaling messages. Please refer to RFC 3775 and RFC 3776 for security considerations related to the use of IPsec with Mobile IPv6. Devarapalli Expires April 18, 2005 [Page 16] Internet-Draft Mobile IPv6 with IKEv2 and revised IPsec October 2004 9. IANA Considerations This document requires no action from IANA. Devarapalli Expires April 18, 2005 [Page 17] Internet-Draft Mobile IPv6 with IKEv2 and revised IPsec October 2004 10. Acknowledgements TBD Devarapalli Expires April 18, 2005 [Page 18] Internet-Draft Mobile IPv6 with IKEv2 and revised IPsec October 2004 11. References 11.1 Normative References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [2] Johnson, D., Perkins, C. and J. Arkko, "Mobility Support in IPv6", RFC 3775, June 2004. [3] Arkko, J., Devarapalli, V. and F. Dupont, "Using IPsec to Protect Mobile IPv6 Signaling Between Mobile Nodes and Home Agents", RFC 3776, June 2004. [4] Kaufman, C., "Internet Key Exchange (IKEv2) Protocol", draft-ietf-ipsec-ikev2-17 (work in progress), October 2004. [5] Kent, S. and K. Seo, "Security Architecture for the Internet Protocol", draft-ietf-ipsec-rfc2401bis-03 (work in progress), September 2004. [6] Kent, S., "IP Encapsulating Security Payload (ESP)", draft-ietf-ipsec-esp-v3-09 (work in progress), October 2004. 11.2 Informative References [7] Kent, S. and R. Atkinson, "Security Architecture for the Internet Protocol", RFC 2401, November 1998. [8] Harkins, D. and D. Carrel, "The Internet Key Exchange (IKE)", RFC 2409, November 1998. [9] Giaretta, G., Guardini, I., Demaria, E., Bournelle, J. and M. Laurent-Maknavicius, "MIPv6 Authorization and Configuration based on EAP", draft-giaretta-mip6-authorization-eap (work in progress), October 2004. [10] Giaretta, G., "Goals for AAA-HA interface", draft-giaretta-mip6-aaa-ha-goals-00 (work in progress), September 2004. [11] Yegin, A., "AAA Mobile IPv6 Application Framework", draft-yegin-mip6-aaa-fwk-00 (work in progress), September 2004. [12] Patel, A., "Problem Statement for bootstrapping Mobile IPv6", draft-ietf-mip6-bootstrap-ps-01 (work in progress), October 2004. Devarapalli Expires April 18, 2005 [Page 19] Internet-Draft Mobile IPv6 with IKEv2 and revised IPsec October 2004 [13] Crocker, D., "Standard for the format of ARPA Internet text messages", STD 11, RFC 822, August 1982. [14] Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J. and H. Levkowetz, "Extensible Authentication Protocol (EAP)", RFC 3748, June 2004. Author's Address Vijay Devarapalli Nokia Research Center 313 Fairchild Drive Mountain View, CA 94043 USA EMail: vijay.devarapalli@nokia.com Devarapalli Expires April 18, 2005 [Page 20] Internet-Draft Mobile IPv6 with IKEv2 and revised IPsec October 2004 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. 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. Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 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. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Devarapalli Expires April 18, 2005 [Page 21]