MIP6 Working Group Hee Jin Jang Internet-Draft Alper Yegin Expires: November 17, 2007 SAMSUNG Kuntal Chowdhury Starent Networks JinHyeock Choi SAMSUNG May 16, 2007 DHCP Option for Home Information Discovery in MIPv6 draft-ietf-mip6-hiopt-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 November 17, 2007. Copyright Notice Copyright (C) The IETF Trust (2007). Jang, et al. Expires November 17, 2007 [Page 1] Internet-Draft DHCP Opt for Home Info Discovery in MIPv6 May 2007 Abstract This draft defines a DHCP-based scheme to enable dynamic discovery of Mobile IPv6 home agent address, home agent FQDN and home subnet. New DHCP options are defined to carry the information from a DHCP server to the DHCP client running on the mobile node. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. DHCP options for HA Dynamic Discovery . . . . . . . . . . . . 5 3.1. Home Network Identifier Option . . . . . . . . . . . . . . 5 3.2. MIP6 Relay Agent Option . . . . . . . . . . . . . . . . . 7 3.2.1. MIP6 Relay Agent Sub-option . . . . . . . . . . . . . 7 3.3. Home Network Information Option . . . . . . . . . . . . . 9 3.3.1. Home Network Information Sub-option . . . . . . . . . 9 4. Option Usage . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.1. Mobile Node Behavior . . . . . . . . . . . . . . . . . . . 11 4.2. NAS/DHCP Relay Agent Behavior . . . . . . . . . . . . . . 12 4.3. DHCP Server Behavior . . . . . . . . . . . . . . . . . . . 13 5. Security Considerations . . . . . . . . . . . . . . . . . . . 15 6. IANA Consideration . . . . . . . . . . . . . . . . . . . . . . 16 7. Normative References . . . . . . . . . . . . . . . . . . . . . 17 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18 Intellectual Property and Copyright Statements . . . . . . . . . . 19 Jang, et al. Expires November 17, 2007 [Page 2] Internet-Draft DHCP Opt for Home Info Discovery in MIPv6 May 2007 1. Introduction Before a mobile node can engage in Mobile IPv6 signaling with a home agent, it should either know the IP address of the home agent via pre-configuration, or dynamically discover it. Mobile IPv6 specification [6] describes how home agents can be dynamically discovered by mobile nodes that know the home subnet prefix. This scheme does not work when prefix information is not already available to the mobile node. This problem can be solved by delivering one or more home subnet prefix information to the mobile node by means of DHCP. Subsequently, the mobile node can engage in dynamic home agent discovery using the prefix information. In addition to delivering the prefix information, DHCP can also be used to provide the IP addresses or FQDNs of the home agents that are available to the mobile node and the home address that the mobile node can use to register with the home agent. The solution involves defining new DHCP options to carry home subnet prefix, home agent IP address and home agent's FQDN information. As part of configuring the initial TCP/IP parameters, a mobile node can obtain home network information for the subnet it is directly attached to, other subnets in the visited domain, or a subnet from its home domain. A mobile node can convey the target home subnet's identity in order to receive corresponding information. For example the mobile node can provide realm portion of its user NAI (Network Access Identifier) and expect that a home network information from its home domain is returned. The availability of the requested information depends on the DHCP server having prior knowledge or dynamically discovering it. While the specific details are outside the scope of this document, use of static tables and AAA-assisted discovery are possible options [12]. The mobile node may or may not be connected to the "home" subnet when it attempts to learn Mobile IPv6 home network information. This allows operators to centrally deploy home agents while being able to bootstrap mobile nodes that are already roaming. This scenario also occurs when HMIPv6 [11] is used, where the mobile node is required to discover the MAP (a special home agent) that is located multiple hops away from the mobile node's attachment point. Jang, et al. Expires November 17, 2007 [Page 3] Internet-Draft DHCP Opt for Home Info Discovery in MIPv6 May 2007 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 RFC2119 [2]. General mobility terminology can be found in RFC3753 [5]. The following additional terms, as defined in RFC4640 [9], are used in this document: Access Service Provider (ASP): A network operator that provides direct IP packet forwarding to and from the mobile node. Mobility Service Provider (MSP): A service provider that provides Mobile IPv6 service. In order to obtain such service, the mobile node must be authenticated and authorized to obtain the Mobile IPv6 service. Jang, et al. Expires November 17, 2007 [Page 4] Internet-Draft DHCP Opt for Home Info Discovery in MIPv6 May 2007 3. DHCP options for HA Dynamic Discovery This section introduces new DHCP options used for dynamic home information discovery in Mobile IPv6. The draft [13] describes the whole interworking procedure for Home Agent assignment among MN, NAS, DHCP, and AAA entities for bootstrapping procedure in the integrated scenario. 3.1. Home Network Identifier Option This option is used to carry the identifier of the target home network. The mobile node MUST include this option along with its Option Request option in its request. Jang, et al. Expires November 17, 2007 [Page 5] Internet-Draft DHCP Opt for Home Info Discovery in MIPv6 May 2007 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OPTION_MIP6-HNID | option-len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | id-type | reserved | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + . . . Home Network Identifier . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ option-code OPTION_MIP6-HNID (TBD) option-len Total length of the option in octets id-type The type of Home Network Identifier: 0 Visited domain (local ASP) 1 The target network 2 No preference reserved An 8-bit field reserved for future use. The value MUST be initialized to 0 by the sender and MUST be ignored by the receiver. Home Network Identifier The identifier to specify the requested home network of the mobile node. This field MUST be set to the network realm as the FQDN defined in [3] when the id-type is 1. The id-type 0 indicates the mobile node is interested in learning the home network information that pertains to the currently visited network. This type can be used to discover local home agents in the local ASP. In this case, the Home Network Identifier field SHOULD be set to 0. Jang, et al. Expires November 17, 2007 [Page 6] Internet-Draft DHCP Opt for Home Info Discovery in MIPv6 May 2007 The id-type 1 indicates the mobile node is interested in learning the home network information that pertains to the given realm. This type can be used to discover home agents that are hosted by a user's home domain (as indicated by his/her NAI-based username -- user@ HomeRealm). The Home Network Identifier field MUST be set to the requested target network which is not in the visited domain. The target network can be a home MSP or a MSP which has trust roaming relationship with the mobile node's home MSP. If the mobile node has no preference, the id-type is set to 2 and the Home Network Identifier SHOULD be initialized to 0. In this case, the assignment of the home network information is within the server's own discretion. For the detailed processing, refer to Section 4. 3.2. MIP6 Relay Agent Option This option carries the RADIUS or Diameter attributes that are received at the NAS from the AAAH. The DHCP relay agent sends this option to the DHCP server in the Relay-Forward message. 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OPTION_MIP6-RELAY | option-len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . sub-options . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ option-code OPTION_MIP6-RELAY (TBD). option-len Total length of the option in octets sub-options A series of sub-options carrying MIP6 bootstrap information. 3.2.1. MIP6 Relay Agent Sub-option This sub-option carries the assigned home network information to the DHCP server. Jang, et al. Expires November 17, 2007 [Page 7] Internet-Draft DHCP Opt for Home Info Discovery in MIPv6 May 2007 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | sub-opt-code | sub-opt-len | reserved | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + . . . Home Network Information . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ sub-opt-code The sub-option identifies the type of the following Home Network Information field. Possible values are: 0 Home subnet prefix 1 Complete IPv6 address of the home agent 2 FQDN of the home agent sub-opt-len An 8-bit unsigned integer. Total length of the following Home Network Information field. reserved An 8-bit field reserved for future use. The value MUST be initialized to 0 by the sender, and MUST be ignored by the receiver. Home Network Information A home subnet prefix, home agent IP address or home agent FQDN to be provided to a mobile node. When the sub-opt-code is set to 0, the data field MUST contain the 8-bit prefix length information followed by the 128-bit IPv6 address beginning with the available network prefix. When the sub-opt-code is set to 1, the data field MUST contain the 128-bit IPv6 address of the home agent. When the sub-opt-code is set to 2, the data field MUST contain the FQDN as described in RFC1035 [1]. Multiple sub-options may exist in a MIP6 Relay Agent option to carry Jang, et al. Expires November 17, 2007 [Page 8] Internet-Draft DHCP Opt for Home Info Discovery in MIPv6 May 2007 more than one home information. 3.3. Home Network Information Option This option is used to carry home network information to a mobile node in the form of one or more of home subnet prefix(es), home agent address(es) and home agent FQDN(s). The server SHOULD provide all of the matching home information in a Home Network Information option. 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OPTION_MIP6-HNINF | option-len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . sub-options . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ option-code OPTION_MIP6-HNINF (TBD). option-len Total length of the option in octets sub-options A series of sub-options carrying MIP6 bootstrap information. 3.3.1. Home Network Information Sub-option This sub-option carries the assigned home network information to the DHCP client. Jang, et al. Expires November 17, 2007 [Page 9] Internet-Draft DHCP Opt for Home Info Discovery in MIPv6 May 2007 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | sub-opt-code | sub-opt-len | reserved | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + . . . Home Network Information . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ sub-opt-code The type of the following Home Network Information field. Possible values are: 0 Home subnet prefix 1 Complete IPv6 address of the home agent 2 FQDN of the home agent sub-opt-len An 8-bit unsigned integer. Total length of the following Home Network Information field. reserved An 8-bit field reserved for future use. The value MUST be initialized to 0 by the sender, and MUST be ignored by the receiver. Home Network Information A home subnet prefix, home agent IP address or home agent FQDN to be provided to a mobile node. All fields are set in the same manner as those of a MIP6 Relay Agent sub-option. Multiple sub-options may exist in a Home Network Information option to carry more than one home information. The detailed processing for each id-type is described in Section 4. Jang, et al. Expires November 17, 2007 [Page 10] Internet-Draft DHCP Opt for Home Info Discovery in MIPv6 May 2007 4. Option Usage The requesting and sending of the proposed DHCP options follow the rules for DHCP options in [4]. The following DHCP options [4] are also required in the solution for normal DHCP operation: - Option Request option - Client Identifier option - Relay Message option - Interface-Id option 4.1. Mobile Node Behavior In order to acquire the home network information, the mobile node SHALL send an Information Request to the All_DHCP_Relay_Agents_and_Servers multicast address. In this message the mobile node (DHCP client) SHALL include the Option Code for Home Network Identifier option in the OPTION_ORO. The mobile node SHALL also include the OPTION_CLIENTID [4] to identify itself to the DHCP server. During requesting the information, the mobile node MUST clarify the preference about the requested home network with the id-type in the Home Network Identifier option. Even if the mobile node does not care about the location of the home network where the home agent to be assigned, it MUST clarify the fact by setting the id-type to 2. In this case the Home Network Identifier SHOULD be set to 0. When the mobile node receives the Reply message from the DHCP server and gets more than one home agent address(es), it MUST have a selection mechanism to determine which one to use for establishing a Mobile IPv6 session. For example, if the mobile node acquires both IPv6 address(es) and FQDN(s) of the home agent(s), it may try to use the address information of the home agent(s) first. If the mobile node wants to retrieve home network information from both the visited network (ASP) and the target MSP with a single transaction, it should request the information by using two Home Network Identifier options with the id-type 0 and the id-type 1. When the mobile node requests the home network information with the id-type 0 or 1 but cannot be provided with the proper information, that is, option-len = 0 in the Home Network Information option, then it may request again by setting the id-type to 2 in the Home Network Identifier option. Jang, et al. Expires November 17, 2007 [Page 11] Internet-Draft DHCP Opt for Home Info Discovery in MIPv6 May 2007 4.2. NAS/DHCP Relay Agent Behavior The NAS and the DHCP relay agent are assumed to be collocated in this solution. The NAS communicates with the mobile node during the network access authentication and interacts with the AAAH (via the AAAV) using either Diameter NASREQ RFC4005 [7] or RADIUS [12] [Editor's note: The Diameter AVPs need to be defined]. Upon receiving the MIP6 related RADIUS or Diameter attributes returned by the AAAH, the NAS passes the information to the collocated DHCP relay agent. Upon receiving the Information Request from the mobile node, the DHCP relay agent MUST forward the message to the DHCP server as per [4]. The relay agent SHALL use the OPTION_CLIENTID to identify the mobile node (user). This is required to check whether there are some additional information for the user that need to be appended while relaying the information request message to the DHCP server. If the relay agent determines that the NAS has passed home network information for this mobile node, the relay agent MUST include the received home network information in the MIP6 Relay Agent option, and attach this option in the Relay-Forward message. The relay agent MAY include the Interface-Id option [4] in the Relay-Forward message. The sub-options that carry home information for the same home agent should be listed in sequential order of a sub-opt-code in the MIP6 Relay Agent option so as to indicate the coupling among home network information for the same home agent or home subnet. For example, the sub-options for HA1 and HA2 are listed as follows. sub-opt-code = 1 (HA1's IPv6 address) sub-opt-code = 2 (HA1's FQDN) sub-opt-code = 0 (Home subnet prefix under HA2) sub-opt-code = 1 (HA2's IPv6 address) sub-opt-code = 2 (HA2's FQDN) The DHCP relay agent MUST insert MN-NAI option [8] in the Relay- Forward message in order to indicate the home network of the user to the DHCP server. This information is compared with the target network in the Home Network Information option when the DHCP server returns the corresponding home network information. Upon receiving the Reply message from the DHCPv6 server, the relay agent SHALL follow the guidelines defined in [4] to forward the Jang, et al. Expires November 17, 2007 [Page 12] Internet-Draft DHCP Opt for Home Info Discovery in MIPv6 May 2007 message to the mobile node. 4.3. DHCP Server Behavior The DHCP server MUST follow the following logic to process Information Request from the mobile node. Information Request message includes: A. OPTION_ORO and Home Network Identifier option with the id-type 0, Interface-Id option, Client Identifier option, MIP6 Relay Agent option. If the DHCP server is configured with the local home information, it MUST include the corresponding information in the Home Network Information option of the Reply message. The information may have been configured statically in the server. B. OPTION_ORO and Home Network Identifier option with the id-type 1, Interface-Id option, Client Identifier option, MIP6 Relay Agent option. If the received Home Network Identifier option does not carry any home MSP, the option is ignored. If the DHCP server has the corresponding information for the specified home MSP, it MUST include the corresponding information in the Home Network Information option. The server may provide the matching information extracted from the MIP6 Relay Agent option. C. OPTION_ORO and Home Network Identifier option with the id-type 2, Interface-Id option, Client Identifier option, MIP6 Relay Agent option. In this case, the assignment of the home information relies on the server's local policy, and the DHCP server SHOULD have its own policy so that it can reply with the proper information. The policy can be determined based on several factors such as the home agent availability and the authorization information of the mobile node. However, the specific policy setting is not in the scope of this document. It is assumed that a DHCP server has some mechanism to know or retrieve the requested Mobile IPv6 information. For instance, as described in [12], the NAS can learn the information via RADIUS during network access authentication, and NAS-collocated DHCP relay can transfer it to the DHCP server by the proposed DHCP option in this document. The DHCP server may gather the home network Jang, et al. Expires November 17, 2007 [Page 13] Internet-Draft DHCP Opt for Home Info Discovery in MIPv6 May 2007 information in other ways, but the specifics of these mechanisms are outside the scope of this document. When the DHCP server provides the home information that is retrieved from the MIP6 Relay Agent option, it MUST compare the NAI's realm information of MN-NAI option with the target network in Home Network Identifier option. If they match, the DHCP server replies with the Reply message after copying the home information in MIP6 Relay Agent option to Home Network Information option. In case the server cannot find any home information for the requested id-type, it MUST return a Home Network Information option with the 0-length data. The sub-options for the same home agent SHOULD be listed in sequential order of a sub-opt-code in the Home Network Information option. In all Reply messages, the DHCP server MUST return the Interface-Id option as received in the Information Request. The DHCP server SHOULD use the Client Identifier option to identify the mobile node. Jang, et al. Expires November 17, 2007 [Page 14] Internet-Draft DHCP Opt for Home Info Discovery in MIPv6 May 2007 5. Security Considerations Secure delivery of home agent, home address, and home link information from a DHCP server to the mobile node (DHCP client) relies on the overall DHCP security. The particular option defined in this draft does not have additional impact on the DHCP security. Aside from the DHCP client to server interaction, an operator must also ensure secure delivery of mobile IP information to the DHCP server. This is outside the scope of DHCP and the newly defined option. Jang, et al. Expires November 17, 2007 [Page 15] Internet-Draft DHCP Opt for Home Info Discovery in MIPv6 May 2007 6. IANA Consideration This document introduces two new DHCPv6 options, Home Agent Request option and Home Agent Reply option. The type numbers for new DHCP options are currently TBD. An appropriate request will be made to IANA if this Internet draft gets accepted as an RFC. Jang, et al. Expires November 17, 2007 [Page 16] Internet-Draft DHCP Opt for Home Info Discovery in MIPv6 May 2007 7. Normative References [1] Mockapetris, P., "Domain names - implementation and specification", STD 13, RFC 1035, November 1987. [2] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [3] Aboba, B. and M. Beadles, "The Network Access Identifier", RFC 2486, January 1999. [4] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., and M. Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3315, July 2003. [5] Manner, J. and M. Kojo, "Mobility Related Terminology", RFC 3753, June 2004. [6] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in IPv6", RFC 3775, June 2004. [7] Calhoun, P., Zorn, G., Spence, D., and D. Mitton, "Diameter Network Access Server Application", RFC 4005, August 2005. [8] Patel, A., Leung, K., Khalil, M., Akhtar, H., and K. Chowdhury, "Mobile Node Identifier Option for Mobile IPv6 (MIPv6)", RFC 4283, November 2005. [9] Patel, A. and G. Giaretta, "Problem Statement for bootstrapping Mobile IPv6 (MIPv6)", RFC 4640, September 2006. [10] Levkowetz, H., "DHCP Option for Mobile IP Mobility Agents", draft-ietf-dhc-mipadvert-opt-02 (work in progress), February 2004. [11] Soliman, H., Castelluccia, C., El Malki, K., and L. Bellier, "Hierarchical Mobile IPv6 Mobility Management (HMIPv6)", RFC 4140, August 2005. [12] Chowdhury, K., "RADIUS Mobile IPv6 Support", draft-ietf-mip6-radius-02 (work in progress), March 2007. [13] Chowdhury, K. and A. Yegin, "MIP6-bootstrapping for the Integrated Scenario", draft-ietf-mip6-bootstrapping-integrated-dhc-03 (work in progress), April 2007. Jang, et al. Expires November 17, 2007 [Page 17] Internet-Draft DHCP Opt for Home Info Discovery in MIPv6 May 2007 Authors' Addresses Hee Jin Jang Samsung Advanced Institute of Technology P.O. Box 111 Suwon 440-600 Korea Email: heejin.jang@samsung.com Alper E. Yegin Samsung Electronics Istanbul Turkey Email: alper01.yegin@partner.samsung.com Kuntal Chowdhury Starent Networks 30 International Place Tewksbury, MA 01876 US Email: kchowdhury@starentnetworks.com JinHyeok Choi Samsung Advanced Institute of Technology P.O. Box 111 Suwon 440-600 Korea Email: athene@sait.samsung.co.kr Jang, et al. Expires November 17, 2007 [Page 18] Internet-Draft DHCP Opt for Home Info Discovery in MIPv6 May 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). 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. 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, THE IETF TRUST 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. Intellectual Property 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. Acknowledgment Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). Jang, et al. Expires November 17, 2007 [Page 19]