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Network Working Group F. AdrangiInternet-DraftRequest for Comments: 4284 V. LortzExpires: February 12, 2006Category: Informational Intel F. Bari Cingular Wireless P. Eronen NokiaAugust 11, 2005January 2006 Identityselection hintsSelection Hints for the Extensible Authentication Protocol (EAP)draft-adrangi-eap-network-discovery-14Status ofthisThis MemoBy 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 ofThis memo provides information for the InternetEngineering 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.community. Itis inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The listdoes not specify an Internet standard ofcurrent Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The listany kind. Distribution ofInternet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on February 12, 2006.this memo is unlimited. Copyright Notice Copyright (C) The Internet Society(2005).(2006). IESG Note: EAP Identity Selection was developed by 3GPP. Documentation is provided as information to the Internet community. The EAP WG has verified that this specification is compatible with EAP as defined in RFC 3748. Required 3GPP client behavior is described in 3GPP TS 24.234. Abstract The Extensible Authentication Protocol (EAP) is defined in[RFC3748].RFC 3748. This document defines a mechanism that allows an access network to provide identity selection hints to an EAP peer--- the end of the link that responds to the authenticator. The purpose is to assist the EAPAdrangi, et al. Expires February 12, 2006 [Page 1] Internet-Draft Identity selection hints for EAP August 2005peer in selecting an appropriate Network Access Identifier (NAI). This is useful in situations where the peer does not receive alower layerlower-layer indication of what network it is connecting to, or when there is no direct roaming relationship between the access network and the peer's home network. In the latter case, authentication is typically accomplished via a mediating network such as a roaming consortium or broker. The mechanism defined in this document is limited in its scalability. It is intended for access networks that have a small to moderate number of direct roaming partners. Adrangi, et al. Informational [Page 1] RFC 4284 Identity Selection Hints for EAP January 2006 Table of Contents 1. Introduction. . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1....................................................2 1.1. Relationship withother specifications . . . . . . . . . . 3 1.2Other Specifications .....................3 1.2. Applicability. . . . . . . . . . . . . . . . . . . . . . 3 1.3..............................................3 1.3. Terminology. . . . . . . . . . . . . . . . . . . . . . . 4................................................4 2. Implementationrequirements . . . . . . . . . . . . . . . . . 5 2.1Requirements .....................................4 2.1. Packetformat . . . . . . . . . . . . . . . . . . . . . . 6Format ..............................................5 3.IANASecurity Considerations. . . . . . . . . . . . . . . . . . . . . 7.........................................6 4.Security considerations . . . . . . . . . . . . . . . . . . . 7 5.Acknowledgements. . . . . . . . . . . . . . . . . . . . . . . 7 6.................................................7 5. Appendix - Delivery Options. . . . . . . . . . . . . . . . . 8 7......................................8 6. References. . . . . . . . . . . . . . . . . . . . . . . . . . 12 7.1.....................................................12 6.1. Normativereferences . . . . . . . . . . . . . . . . . . . 12 7.2References ......................................12 6.2. Informativereferences . . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 13 Intellectual Property and Copyright Statements . . . . . . . . 14 Adrangi, et al. Expires February 12, 2006 [Page 2] Internet-Draft Identity selection hints for EAP August 2005References ....................................12 1. Introduction The Extensible Authentication Protocol (EAP) is defined in [RFC3748]. An EAP peer (hereafter, also referred to as the peer) may have multiple credentials. Where the lower layer does not provide an indication of which network it is connecting to, or where its home network may have roaming relationships with several mediating networks, the peer may be uncertain of which Network AccessIdentityIdentifier (NAI) to include in an EAP-Response/Identity. This document defines a mechanism that allows the access network to provide an EAP peer with identity selection hints, including information about its roaming relationships. This information is sent to the peer in an EAP-Request/Identity message by appending it after the displayable message and a NUL character. This mechanism may assist the peer in selecting a credential and associated NAI, or in formatting the NAI[rfc2486bis][RFC4282] to facilitate routing ofAAAAuthentication, Authorization, and Accounting (AAA) messages to the home AAA server. If there are several mediating networks available, the peer can influence which one is used. Exactly how the selection is made by the peer depends largely on the peer's local policy and configuration, and is outside the scope of this document. For example, the peer could decide to use one of its other identities, decide to switch to another access network, or attempt to reformat its NAI[rfc2486bis][RFC4282] to assist in proper AAA routing. The exact clientbehaviourbehavior is described by standard bodies using this specification such as 3GPP[TS 24.234].[TS-24.234]. Section 2 describes the required behavior of implementations, including the format for identity hints.1.1Adrangi, et al. Informational [Page 2] RFC 4284 Identity Selection Hints for EAP January 2006 1.1. Relationship withother specificationsOther Specifications This document specifies behavior ofRADIUSRemote Authentication Dial-In User Service (RADIUS) proxies that handle EAP messages. This includes the specification of the behavior of proxies in response to an unknown realm within the User-Name(1) attribute of an Access-Request containing one or more EAP-Message attributes. This document, if used in a scenario requiring NAI "decoration" as specified in[rfc2486bis],[RFC4282], assumes asource routingsource-routing model for determination of the roaming relationship path, and therefore affects the behavior of RADIUS proxies in roaming situations.1.21.2. Applicability Identity hints are useful in situations where the peer cannot determine which credentials to use, or where there may be multipleAdrangi, et al. Expires February 12, 2006 [Page 3] Internet-Draft Identity selection hints for EAP August 2005alternative routes by which an access network can reach a home network. This can occur when access networks support multiple roaming consortiums but do not have a full list of the home networks reachable through them. In such scenarios, identity hints (e.g., a list of roaming partners of the access network) can be provided to enable the EAP peer to influence route selection, using the NAI[RFC2486bis][RFC4282] to specify the desired source route. The immediate application of the proposed mechanism is in 3GPP systems interworking with WLANs[TS 23.234][TS-23.234] and[TS 24.234].[TS-24.234]. The number of hints that can be provided by this mechanism is limited by the EAP MTU. For example, assuming 20 octets per hint and an EAP MTU of 1096, a maximum of 50 roaming partners can be advertised. Scaling limitations imposed by the EAP MTU should be taken into account when deploying this solution. Since this mechanism relies on information provided in theEAP- Request/IdentityEAP-Request/Identity packet, it is necessary for the peer to select a point of attachment prior to obtaining identity hints. Where there are multiplepointpoints of attachment available, the mechanism defined in this specification does not allow the peer to utilize the identity hints in making a decision about which point of attachment to select. In roaming situations, this can require the peer to try multiple points of attachment before it finds a compatible one, increasing handoff latency. This document is related to the general network discovery and selection problem described in [netsel-problem]. The proposed mechanism described in this document solves only a part of the problem in [netsel-problem]. IEEE 802.11 is also looking into more Adrangi, et al. Informational [Page 3] RFC 4284 Identity Selection Hints for EAP January 2006 comprehensive and long-term solutions for network discovery and selection.1.31.3. 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]. NAI NetworkAddressAccess Identifier[rfc2486bis].[RFC4282]. Decorated NAI An NAI specifying a source route. See[rfc2486bis] section[RFC4282] Section 2.7 for more information.Adrangi, et al. Expires February 12, 2006 [Page 4] Internet-Draft Identity selection hints for EAP August 2005NAI Realm Realm portion of an NAI[rfc2486bis].[RFC4282]. 2. ImplementationrequirementsRequirements The EAP authenticator MAY send an identity hint to the peer in the initial EAP-Request/Identity. If the identity hint is not sent initially (such as when the authenticator does not support this specification), then the EAP peer may select the wrong NAI. If the local AAA proxy does not have a default route configured, then it may find that the User-Name(1) attribute in the request contains a realm for which there is no corresponding route. As noted in [RFC2607], Section 5.1: "Proxies are frequently used to implement policy in roaming situations. Proxies implementing policy MAY reply directly to Access-Requests without forwarding the request. When replying directly to an Access-Request, the proxy MUST reply either with an Access-Reject or an Access-Challenge packet. A proxy MUST NOT reply directly with an Access-Accept." Where no route is found, existing AAA proxies will typically send an Access-Reject. However, where the request contains an EAP-Message attribute, AAA proxies implementing this specification should instead reply with a challenge including an identity hint. For example, if a RADIUS proxy receives an Access-Request with an EAP-Message attribute and a User-Name(1) attribute containing an unknown realm, it SHOULD reply with an Access-Challenge with anEAP- MessageEAP-Message attribute encapsulating an EAP-Request/Identity packet containing an identity hint, rather than an Access-Reject. See"option"Option 3" in the appendix for the message flow diagram. Adrangi, et al. Informational [Page 4] RFC 4284 Identity Selection Hints for EAP January 2006 If the peer responds with an EAP-Response/Identity containing an unknown realm after the local AAA proxy sends an identity hint, then a local AAA proxy/server implementing this specification MUST eventually send an Access-Reject containing an EAP-Failure. Prior to doingsoso, it MAY send an Access-Challenge containing anEAP- Notification,EAP-Notification, in order to provide an explanation for the failure. In order to determine whether an identity hint had been previously sent, the State(24) attribute defined in [RFC2865] can be used. As noted in [RFC3748], Section 3.1, the minimum EAP MTU size is 1020 octets. EAP does not support fragmentation of EAP-Request/Identity messages, so the maximum length of the identity hint information is limited by the link MTU.Adrangi, et al. Expires February 12, 2006 [Page 5] Internet-Draft Identity selection hints for EAP August 2005 2.12.1. PacketformatFormat TheIdentityidentity hint information is placed after the displayable string and a NUL character in the EAP-Request/Identity. The following ABNF[RFC2234][RFC4234] defines an NAIRealms attribute for presenting the identity hint information. The attribute's value consists of a set of realm names separated by a semicolon. identity-request-data = [ displayable-string ]"%x00"%x00 [ Network-Info ] displayable-string = *CHAR Network-Info = "NAIRealms=" realm-list Network-Info =/ 1*OCTET ",NAIRealms=" realm-list Network-Info =/ "NAIRealms=" realm-list "," 1*OCTET Network-Info =/ 1*OCTET ",NAIRealms=" realm-list "," 1*OCTET realm-list = realm / ( realm-list ";" realm ) The "OCTET" and "CHAR" rules are defined in[RFC2234][RFC4234] and the "realm" rule is defined in[rfc2486bis].[RFC4282]. Adrangi, et al. Informational [Page 5] RFC 4284 Identity Selection Hints for EAP January 2006 A sample hex dump of an EAP-Request/Identity packet is shown below. 01 ; Code: Request 00 ; Identifier: 0 00433f ; Length:6763 octets 01 ; Type: Identity 48 65 6c 6c 6f 21 00 4e ; "Hello!\0NAIRealms=example.com;mnc014. 41 49 52 65 61 6c 6d 73 ; mcc310.3gppnetwork.org" 3d69 73 70 2e65 78 61 6d 70 6c 65 2e 63 6f 6d 3b 6d 6e 63 30 31 34 2e 6d 63 63 33 31 30 2e 33 67 70 70 6e 65 74 77 6f 72 6b 2e 6f 72 67 The Network-Info can containaan NAIRealms list in addition to proprietary information. The proprietary information can be placed before or after the NAIRealms list. To extract the NAIRealms list, an implementation can either find the "NAIRealms=" immediately after the NUL or seek forward to find ",NAIRealms" somewhere in the string. The realms data ends either at the first "," or at the end of the string, whichever comes first.Adrangi, et al. Expires February 12, 2006 [Page 6] Internet-Draft Identity selection hints for EAP August 20053.IANA Considerations This document does not define any new namespaces to be managed by IANA, and does not require any assignments in existing namespaces. 4.SecurityconsiderationsConsiderations Identity hint information is delivered inside an EAP-Request/Identity before the authentication conversation begins. Therefore, it can be modified by an attacker. The NAIRealms attribute therefore MUST be treated as a hint by the peer. That is, the peer must treat the hint as an unreliable indication Unauthenticated hints may result in peers inadvertently revealing additional identities, thus compromising privacy. Since theEAP- Response/IdentityEAP-Response/Identity is sent in the clear, this vulnerability already exists. This vulnerability can be addressed via method-specific identity exchanges. Similarly, in a situation where the peer has multiple identities to choose from, an attacker can use a forged hint to convince the peer to choose an identity bound to a weak EAP method. Requiring the use of strong EAP methods can protect against this. A similar issue already exists with respect to unprotectedlink layerlink-layer advertisements such as 802.11 SSIDs. If the identity hint is used to select a mediating network, existing EAP methods may not provide a way for the home AAA server to verify that the mediating network selected by the peer was actually used. Adrangi, et al. Informational [Page 6] RFC 4284 Identity Selection Hints for EAP January 2006 Any information revealed either from the network or client sides before authentication has occurred can be seen as a security risk. For instance, revealing the existence of a network that uses a weak authentication method can make it easier for attackers to discover that such a network is accessible. Therefore, the consent of the network being advertised in the hints is required before such hints can be sent.5.4. Acknowledgements The authors wouldspeciallyespecially like to thank Jari Arkko, Bernard Aboba, and Glen Zorn for their help in scoping the problem, and for reviewing thedraft workdocument in progress andforsuggesting improvements to it. The authors would also like to acknowledge and thank Adrian Buckley, Blair Bullock, Jose Puthenkulam, Johanna Wild, Joe Salowey, Marco Spini, Simone Ruffino, Mark Grayson, Mark Watson, and Avi Lior for their support,feedbackfeedback, and guidance during the various stages of this work. Adrangi, et al.Expires February 12, 2006Informational [Page 7]Internet-DraftRFC 4284 Identityselection hintsSelection Hints for EAPAugust 2005 this work. 6.January 2006 5. Appendix - Delivery Options Although the delivery options are described in the context of IEEE 802.11 access networks, they are also applicable to other access networks that use EAP [RFC3748] for authentication and use the NAI format[rfc2486bis][RFC4282] for identifying users. The options assume that the AAA protocol in use is RADIUS [RFC2865]. However, Diameter [RFC3588] could also be used instead of RADIUS without introducing significant architectural differences. The main difference amongst the options is which entity in the access network creates the EAP-Request/Identity. For example, the role of the EAP server may be played by the EAP authenticator (where an initial EAP-Request/Identity is sent with an identity hint) or a RADIUS proxy/server (where theNAI RealmNAIRealm is used for forwarding). The RADIUS proxy/server acts only on the RADIUSUserName(1)User-Name(1) attribute and does not have to parse the EAP-Message attribute. Adrangi, et al. Informational [Page 8] RFC 4284 Identity Selection Hints for EAP January 2006 Option 1: Initial EAP-Request/Identity from the access point In typical IEEE 802.11 wireless LANs, the initial EAP-Request/ Identity is sent by the access point (i.e., EAP authenticator). In the simplest case, the identity hint information is simply included in this request, as shown below. EAP Access Point local RADIUS home RADIUS Peer proxy/server server | 1. EAP | | | | Request/Identity | | | | (NAIRealms) | | | |<------------------| | | | 2. EAP | | | | Response/Identity| | | |------------------>| | | | | 3. Access-Request | | | | (EAP | | | | Response/Identity)| | | |------------------->| | | | |4.Access-Request4. Access-Request | | | | (EAP | | | | Response/Identity) | | | |------------------->| | | | |Adrangi, et al. Expires February 12, 2006 [Page 8] Internet-Draft Identity selection hints for EAP August 2005|<-------------------EAP conversation ----------------------->| Current access points do not support this mechanism, so other options may be preferable. This option can also require configuring the identity hint information in a potentially large number of access points, which may be problematic if the information changes often. Option 2: Initial EAP-Request/Identity from the local RADIUSproxy/serverproxy/ server This is similar to Option 1, but the initial EAP-Request/Identity is created by the local RADIUS proxy/server instead of the access point. Once a peer associates with an access network AP using IEEE 802.11 procedures, the AP sends an EAP-Start message [RFC3579] within a RADIUS Access-Request. The access network RADIUS server can then send the EAP-Request/Identity containing the identity hint information. Adrangi, et al. Informational [Page 9] RFC 4284 Identity Selection Hints for EAP January 2006 EAP Access Point local RADIUS home RADIUS Peer proxy/server server | | 1. Access-Request | | | | (EAP-Start) | | | |------------------->| | | |2.Access-Challenge |2. Access-Challenge| | | | (EAP | | | | Request/Identity | | | | with NAIRealms) | | | |<-------------------| | | 3. EAP | | | | Request/Identity | | | | (NAIRealms) | | | |<------------------| | | | 4. EAP | | | | Response/Identity | | | |------------------>| | | | | 5. Access-Request | | | | (EAP | | | | Response/Identity) | | | |------------------->| | | | | 6. Access-Request | | | | (EAP | | | | Response/Identity) | | | |------------------->| | | | | |<------------------- EAP conversation ---------------------->|Adrangi, et al. Expires February 12, 2006 [Page 9] Internet-Draft Identity selection hints for EAP August 2005This option can work with current access points if they support the EAP-Start message. Option 3: Subsequent EAP-Request/Identity from local RADIUS proxy/ server In the third option, the access point sends the initial EAP-Request/ Identity without any hint information. The peer then responds with an EAP-Response/Identity, which is forwarded to the local RADIUS proxy/server. If the RADIUS proxy/server cannot route the message based on the identity provided by the peer, it sends a secondEAP- Request/IdentityEAP-Request/Identity containing the identity hint information. Adrangi, et al.Expires February 12, 2006Informational [Page 10]Internet-DraftRFC 4284 Identityselection hintsSelection Hints for EAPAugust 2005January 2006 EAP Access Point local RADIUS home RADIUS PeerProxy/Serverproxy/server server | | | | | 1. EAP | | | | Request/Identity | | | | (w/o NAIRealms) | | | |<------------------| | | | 2. EAP | | | | Response/Identity | | | |------------------>| | | | | 3. Access-Request | | | | (EAP | | | | Response/Identity) | | | |------------------->| | | |4.Access-Challenge |4. Access-Challenge| | | | (EAP | | | | Request/Identity | | | | with NAIRealms) | | | |<-------------------| | | 5. EAP | | | | Request/Identity | | | | (NAIRealms) | | | |<------------------| | | | 6. EAP | | | | Response/Identity | | | |------------------>| | | | | 7. Access-Request | | | | (EAP | | | | Response/Identity) | | | |------------------->| | | | | | ======================Failure due to unknown realm============= | | | | | |7a.Access-Reject7a. Access-Reject | | | | (EAP-Failure) | | | |<-------------------| | | 7b. EAP | | | | Failure | | | |<------------------| | | ================================================================ | | | | | | | 8. Access-Request | | | | (EAP | | | | Response/Identity) | | | |------------------->| | | | | |<-------------------- EAP conversation --------------------->| Adrangi, et al.Expires February 12, 2006Informational [Page 11]Internet-DraftRFC 4284 Identityselection hintsSelection Hints for EAPAugust 2005January 2006 This option does not require changes to existing NASes, so it may be preferable in many environments.7.6. References7.16.1. Normativereferences [rfc2486bis]References [RFC4282] Aboba, B., Beadles, M., Arkko, J., and P. Eronen, "The Network Access Identifier",draft-ietf-radext-rfc2486bis-05 (work in progress), July 2004.RFC 4282, December 2005. [RFC3748] Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H. Levkowetz, "Extensible Authentication Protocol (EAP)", RFC 3748, June 2004. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.[RFC2234][RFC4234] Crocker,D., Ed.D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", RFC2234, November 1997.4234, October 2005. [RFC2607] Aboba, B. and J. Vollbrecht, "Proxy Chaining and Policy Implementation in Roaming", RFC 2607, June 1999.7.26.2. InformativereferencesReferences [RFC3579] Aboba, B. and P. Calhoun, "RADIUS (Remote Authentication Dial In User Service) Support For Extensible Authentication Protocol (EAP)", RFC 3579, September 2003. [netsel-problem] Arkko, J. and B. Aboba, "Network Discovery and Selection Problem",draft-ietf-eap-netsel-problem-02 (workWork inprogress), July 2004. [TS 23.234]Progress, October 2005. [TS-23.234] 3GPP TS 23.234 V6.6.0, "3GPP System to Wireless Local Area Network (WLAN)interworking. Stage 2. (www.3gpp.org)", Release 6 3GPP/ WLAN Stage 2 Specificationinterworking; System description (Release 6)", September 2005. [TS-24.234] 3GPP TS23.234. [TS 24.234]24.234 V6.4.0, "3GPP System to Wireless Local Area Network (WLAN)interworking. Stage 3. (www.3gpp.org)", Release 6 3GPP/ WLANinterworking; User Equipment (UE) to network protocols; Stage2 Specification TS 24.234.3 (Release 6)", September 2005. [RFC3588] Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J.Adrangi, et al. Expires February 12, 2006 [Page 12] Internet-Draft Identity selection hints for EAP August 2005Arkko, "Diameter Base Protocol", RFC 3588, September 2003. Adrangi, et al. Informational [Page 12] RFC 4284 Identity Selection Hints for EAP January 2006 [RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson, "Remote Authentication Dial In User Service (RADIUS)", RFC 2865, June 2000. Authors' Addresses Farid Adrangi Intel Corporation 2111 N.E. 25th Avenue Hillsboro, OR 97124 USA Phone: +1 503-712-1791Email:EMail: farid.adrangi@intel.com Victor Lortz Intel Corporation 2111 N.E. 25th Avenue Hillsboro, OR 97124 USA Phone: +1 503-264-3253Email:EMail: victor.lortz@intel.com Farooq Bari Cingular Wireless 7277 164th Avenue N.E. Redmond, WA 98052 USA Phone: +1 425-580-5526Email:EMail: farooq.bari@cingular.com Pasi Eronen Nokia Research Center P.O. Box 407 FIN-00045 Nokia Group FinlandEmail:EMail: pasi.eronen@nokia.com Adrangi, et al.Expires February 12, 2006Informational [Page 13]Internet-DraftRFC 4284 Identityselection hintsSelection Hints for EAPAugust 2005January 2006 Full Copyright Statement Copyright (C) The Internet Society (2006). 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 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 PropertyStatementThe 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 (2005). 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. AcknowledgmentAcknowledgement Funding for the RFC Editor function iscurrentlyprovided by theInternet Society.IETF Administrative Support Activity (IASA). Adrangi, et al.Expires February 12, 2006Informational [Page 14] ----