Diameter Maintenance and J. Korhonen, Ed. Extensions (DIME) TeliaSonera Internet-Draft H. Tschofenig Intended status: Standards Track Nokia Siemens Networks Expires: May 21, 2008 M. Arumaithurai University of Goettingen M. Jones Bridgewater Systems November 18, 2007 Quality of Service Attributes for Diameter draft-ietf-dime-qos-attributes-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 May 21, 2008. Copyright Notice Copyright (C) The IETF Trust (2007). Abstract This document extends the QoSFilterRule AVP functionality of the Diameter Base protocol and the functionality of the QoS-Filter-Rule AVP defined in RFC 4005. The ability to convey Quality of Service Korhonen, et al. Expires May 21, 2008 [Page 1] Internet-Draft QoS Attributes for Diameter November 2007 information using the AVPs defined in this document is available to existing Diameter applications where permitted by the command ABNF and to all new applications. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Diameter QoS Defined AVPs . . . . . . . . . . . . . . . . . . 3 3.1. QoS-Capability AVP . . . . . . . . . . . . . . . . . . . . 3 3.2. QoS-Profile-Template AVP . . . . . . . . . . . . . . . . . 4 3.3. QoS-Resources AVP . . . . . . . . . . . . . . . . . . . . 4 3.4. Extended-QoS-Filter-Rule AVP . . . . . . . . . . . . . . . 5 3.5. QoS-Profile AVP . . . . . . . . . . . . . . . . . . . . . 5 3.6. QoS-Profile-ID AVP . . . . . . . . . . . . . . . . . . . . 5 3.7. QoS-Semantics . . . . . . . . . . . . . . . . . . . . . . 5 3.8. QoS-Parameters AVP . . . . . . . . . . . . . . . . . . . . 6 3.9. QoS-Flow-State AVP . . . . . . . . . . . . . . . . . . . . 6 3.10. QoS-Flow-Direction AVP . . . . . . . . . . . . . . . . . . 6 4. Semantics of QoS Parameters . . . . . . . . . . . . . . . . . 7 5. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5.1. Diameter EAP with QoS Information . . . . . . . . . . . . 8 5.2. Diameter NASREQ with QoS Information . . . . . . . . . . . 9 5.3. QoS Authorization . . . . . . . . . . . . . . . . . . . . 10 5.4. Diameter Server Initiated Re-authorization of QoS . . . . 11 5.5. Diameter Credit Control with QoS Information . . . . . . . 12 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 8. Security Considerations . . . . . . . . . . . . . . . . . . . 14 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14 9.1. Normative References . . . . . . . . . . . . . . . . . . . 14 9.2. Informative References . . . . . . . . . . . . . . . . . . 15 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15 Intellectual Property and Copyright Statements . . . . . . . . . . 16 Korhonen, et al. Expires May 21, 2008 [Page 2] Internet-Draft QoS Attributes for Diameter November 2007 1. Introduction This document defines a number of Diameter Quality of Service (QoS) related AVPs that can be used in existing Diameter applications where permitted by the command ABNF and in all new applications. The Extended-QoS-Filter-Rule AVP thereby replaces the QoSFilterRule, defined in RFC 3588 [RFC3588], and the QoS-Filter-Rule, defined in RFC 4005 [RFC4005]. 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 [RFC2119]. 3. Diameter QoS Defined AVPs The following table lists the Diameter AVPs used by this document, their AVP code values, types, possible flag values, and whether the AVP may be encrypted. +------------------+ | AVP Flag Rules | +-------------------------------------------------|----+---+----+----+ | AVP Section |MUST|MAY|SHLD|MUST| | Attribute Name Code Defined Data Type | | | NOT| NOT| +-------------------------------------------------+----+---+----+----+ |QoS-Capability TBD 3.1 Grouped | |M,P| | V | |QoS-Profile-Template TBD 3.2 Unsigned64 | |M,P| | V | |QoS-Resources TBD 3.3 Grouped | |M,P| | V | |Extended-QoS-Filter-Rule TBD 3.4 Grouped | |M,P| | V | |QoS-Profile TBD 3.5 Grouped | |M,P| | V | |QoS-Profile-ID TBD 3.6 Unsigned32 | |M,P| | V | |QoS-Semantics TBD 3.7 Enumerated | |M,P| | V | |QoS-Parameters TBD 3.8 OctetString| |M,P| | V | |QoS-Flow-State TBD 3.9 Enumerated | |M,P| | V | |QoS-Flow-Direction TBD 3.10 Enumerated | |M,P| | V | +-------------------------------------------------+----+---+----+----+ 3.1. QoS-Capability AVP The QoS-Capability AVP (AVP Code TBD) is of type Grouped and contains a list of supported Quality of Service profile templates (and therefore the support of the respective parameter AVPs). Korhonen, et al. Expires May 21, 2008 [Page 3] Internet-Draft QoS Attributes for Diameter November 2007 QoS-Capability ::= < AVP Header: XXX > 1* { QoS-Profile-Template } * [ AVP ] 3.2. QoS-Profile-Template AVP The QoS-Profile-Template AVP (AVP Code TBD) is of type Unsigned64 and contains the vendor and a specifier field. The 64-bit value in the QoS-Profile-Template AVP is structured as shown below. 0 1 2 3 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Vendor | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Specifier | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Vendor Field: 32 bits of IANA SMI Network Management Private Enterprise Code. The Vendor-ID 0x00000000 is reserved for IANA registered QoS profiles. Specifier Field: 32-bit unsigned integer, representing the defined profile value. An initial QoS profile template is defined with vendor field set to 0x00000000 and the specifier field set to 0, as described in [I-D.ietf-dime-qos-parameters]. The registry for the QoS profile templates is created with the same document. 3.3. QoS-Resources AVP The QoS-Resources AVP (AVP Code TBD) is of type Grouped and includes a description of the Quality of Service resources for policing traffic flows. QoS-Resources ::= < AVP Header: XXX > 0* [ Extended-QoS-Filter-Rule ] [ QoS-Profile ] [ QoS-Flow-State ] * [ AVP ] Korhonen, et al. Expires May 21, 2008 [Page 4] Internet-Draft QoS Attributes for Diameter November 2007 3.4. Extended-QoS-Filter-Rule AVP The Extended-QoS-Filter-Rule AVP (AVP Code TBD) is of type Grouped and defines one or more traffic flows together with the QoS profile that should be applied to the flow(s) by the Resource Management Function. This AVP re-uses the RADIUS NAS-Traffic-Rule AVP [I-D.ietf-radext-filter-rules] to describe traffic flows. The Extended-QoS-Filter-Rule AVP ties a specific traffic filter to a QoS- Profile-ID that in turn refers to a specific set of QoS parameters. At least either one of the NAS-Traffic-Rule or the QoS-Flow-Direction AVPs SHOULD be included. Extended-QoS-Filter-Rule ::= < AVP Header: XXX > [ QoS-Profile-ID ] [ NAS-Traffic-Rule ] [ QoS-Flow-Direction ] * [ AVP ] 3.5. QoS-Profile AVP The QoS-Profile AVP (AVP Code TBD) is of type Grouped and ties the QoS-Profile-ID AVP to a set of QoS-Parameters AVPs. All parameters refer to the same QoS model/profile described by the QoS-Profile- Template AVP. QoS-Profile ::= < AVP Header: XXX > [ QoS-Profile-ID ] { QoS-Semantics } { QoS-Profile-Template } [ QoS-Parameters ] * [ AVP ] 3.6. QoS-Profile-ID AVP The QoS-Profile-ID AVP (AVP Code TBD) is of type Unsigned32 and references a set of QoS-Parameters AVPs. 3.7. QoS-Semantics The QoS-Semantics AVP (AVP Code TBD) is of type Enumerated and provides the semantics for the content of the QoS-Profile AVP. This document defines the following values: Korhonen, et al. Expires May 21, 2008 [Page 5] Internet-Draft QoS Attributes for Diameter November 2007 (0): QoS-Desired (1): QoS-Available (2): QoS-Reserved (3): Minimum-QoS (4): QoS-Authorized 3.8. QoS-Parameters AVP The QoS-Parameters AVP (AVP Code TBD) is of type OctetString and contains Quality of Service parameters. These parameters are defined in a separate document, see [I-D.ietf-dime-qos-parameters]. 3.9. QoS-Flow-State AVP The QoS-Flow-State AVP (AVP Code TBD) is of type Enumerated. It gives an indication as to how the flow has to be treated. The Extended-QoS-Filter-Rule already provides an indicate whether a flow is permitted or denied. This optional AVP provides additional information about the treatment. Currently, a single value is defined; further values are available via IANA registration. Value | Name and Semantic ------+------------------------------------------------------------ 0 | QOS_FLOW_STATE_PENDING - The QoS reservation is kept | pending. The QoS resources are not installed and subsequent | QoS signaling is necessary to active them. 3.10. QoS-Flow-Direction AVP The QoS-Flow-Direction AVP (AVP Code TBD) is of type Enumerated. It gives an indication of the direction the provided QoS information should be applied to. The QoS information can be applied to downlink flows or to uplink flows. The QoS-Flow-Direction AVP may be used in conjunction with the NAS-Traffic-Rule AVP. In a case conflicting definitions between the QoS-Flow-Direction and the NAS-Traffic-Rule, the QoS-Flow-Direction has precedence meaning the filter rules are applied only to the flows going to the direction indicated by the QoS-Flow-Direction AVP. In the absence of the QoS-Flow-Direction the default treatment is to both directions. Value | Name and Semantic ------+------------------------------------------------------------ 0 | QOS_FLOW_DIRECTION_BOTH - The QoS information in applied to | both downlink and uplink flows. This is also the default. 1 | QOS_FLOW_DIRECTION_DL - The QoS information in applied to | downlink flows only. 2 | QOS_FLOW_DIRECTION_UL - The QoS information in applied to Korhonen, et al. Expires May 21, 2008 [Page 6] Internet-Draft QoS Attributes for Diameter November 2007 | uplink flows only. 4. Semantics of QoS Parameters The QoS parameters carried in the QoS-Resources AVP may appear in different messages. The semantic of the QoS parameters depend on the information provided in the QoS-Semantics AVP which currently defines 5 values, namely QoS-Desired (0), QoS-Available (1), QoS-Reserved (2), Minimum-QoS (3), and QoS-Authorized (4). The semantics of the different values are as follows: Object Type Direction Semantic ---------------------------------------------------------------------- QoS-Desired C->S Please authorize the indicated QoS QoS-Desired C<-S NA QoS-Available C->S Admission Control at router indicates that this QoS is available. (note 1) QoS-Available C<-S Indicated QoS is available. (note 2) QoS-Reserved C->S Used for reporting during accounting. QoS-Reserved C<-S NA Minimum-QoS C->S Indicates that the client is not interested interested in authorizing QoS that is lower than Min. QoS Minimum-QoS C<-S The client must not provide QoS guarantees lower than Min. QoS QoS-Authorized C->S NA QoS-Authorized C<-S Indicated QoS authorized Legend: C: Diameter client S: Diameter server NA: Not applicable to this document; no semantic defined in this specification Notes: (1) QoS-Available is only useful in relationship with QoS-Desired (and optionally with Minimum-QoS). (2) QoS-Available is only useful when the AAA server performs admission control and knows about the resources in the network. Korhonen, et al. Expires May 21, 2008 [Page 7] Internet-Draft QoS Attributes for Diameter November 2007 5. Examples This section shows a number of signaling flows where QoS negotiation and authorization is part of the conventional NASREQ, EAP or Credit Control applications message exchanges. The signalling flows for the Diameter QoS Application are described in [I-D.ietf-dime-diameter-qos]. 5.1. Diameter EAP with QoS Information Figure 11 shows a simple signaling flow where a NAS (Diameter Client) announces its QoS awareness and capabilities included into the DER message and as part of the access authentication procedure. Upon completion of the EAP exchange, the Diameter Server provides a pre- provisioned QoS profile with the QoS-Semantics in the QoS-Profile AVP set to "QoS-Authorized", to the NAS in the final DEA message. Korhonen, et al. Expires May 21, 2008 [Page 8] Internet-Draft QoS Attributes for Diameter November 2007 End Diameter Diameter Host Client server | | | | (initiate EAP) | | |<------------------------------>| | | | Diameter-EAP-Request | | | EAP-Payload(EAP Start) | | | QoS-Capability | | |------------------------------->| | | | | | Diameter-EAP-Answer | | Result-Code=DIAMETER_MULTI_ROUND_AUTH | | | EAP-Payload(EAP Request #1) | | |<-------------------------------| | EAP Request(Identity) | | |<-------------------------------| | : : : : <<>> : : : : | | | | EAP Response #N | | |------------------------------->| | | | Diameter-EAP-Request | | | EAP-Payload(EAP Response #N) | | |------------------------------->| | | | | | Diameter-EAP-Answer | | | Result-Code=DIAMETER_SUCCESS | | | EAP-Payload(EAP Success) | | | [EAP-Master-Session-Key] | | | (authorization AVPs) | | | QoS-Resources(QoS-Authorized) | | |<-------------------------------| | | | | EAP Success | | |<-------------------------------| | | | | Figure 11: Example of a Diameter EAP enhanced with QoS Information 5.2. Diameter NASREQ with QoS Information Figure 12 shows a similar pre-provisioned QoS signaling as in Figure 11 but using the NASREQ application instead of EAP application. Korhonen, et al. Expires May 21, 2008 [Page 9] Internet-Draft QoS Attributes for Diameter November 2007 End Diameter Host NAS Server | | | | Start Network | | | Attachment | | |<---------------->| | | | | | |AA-Request | | |NASREQ-Payload | | |QoS-Capability | | +----------------------------->| | | | | | AA-Answer| | Result-Code=DIAMETER_MULTI_ROUND_AUTH| | NASREQ-Payload(NASREQ Request #1)| | |<-----------------------------+ | | | | Request | | |<-----------------+ | | | | : : : : <<>> : : : : | Response #N | | +----------------->| | | | | | |AA-Request | | |NASREQ-Payload ( Response #N )| | +----------------------------->| | | | | | AA-Answer| | | Result-Code=DIAMETER_SUCCESS| | | (authorization AVPs)| | |QoS-Resources(QoS-Authorized) | | |<-----------------------------+ | | | | Success | | |<-----------------+ | | | | Figure 12: Example of a Diameter NASREQ enhanced with QoS Information 5.3. QoS Authorization Figure 13 shows an example of authorization only QoS signaling as part of the NASREQ message exchange. The NAS provides the Diameter server with the "QoS-Desired" QoS-Semantics AVP included in the QoS- Resources AVP. The Diameter server then either authorizes the Korhonen, et al. Expires May 21, 2008 [Page 10] Internet-Draft QoS Attributes for Diameter November 2007 indicated QoS or rejects the request and informs the NAS about the result. In this scenario the NAS does not need to include the QoS- Capability AVP in the AAR message as the QoS-Resources AVP implicitly does the same and also the NAS is authorizing a specific QoS profile, not a pre-provisioned one. End Diameter Host NAS Server | | | | | | | QoS Request | | +----------------->| | | | | | |AA-Request | | |Auth-Request-Type=AUTHORIZE_ONLY | |NASREQ-Payload | | |QoS-Resources(QoS-Desired) | | +----------------------------->| | | | | | AA-Answer| | | NASREQ-Payload(Success)| | | QoS-Resources(QoS-Authorized)| | |<-----------------------------+ | Accept | | |<-----------------+ | | | | | | | | | | Figure 13: Example of an Authorization-Only Message Flow 5.4. Diameter Server Initiated Re-authorization of QoS Figure 14 shows a message exchange for a Diameter server initiated QoS re-authorization procedure. The Diameter server sends the NAS a RAR message requesting re-authorization for an existing session and the NAS acknowledges it with a RAA message. The NAS is aware of its existing QoS profile and information for the ongoing session that the Diameter server requested for re-authorization. Thus, the NAS must initiate re-authorization of the existing QoS profile. The re- authorization procedure is the same as in Figure 13. Korhonen, et al. Expires May 21, 2008 [Page 11] Internet-Draft QoS Attributes for Diameter November 2007 End Diameter Host NAS Server | | | | | | : : : : <<>> : : : : | | | | | RA-Request | | |<-----------------------------+ | | | | |RA-Answer | | |Result-Code=DIAMETER_SUCCESS | | +----------------------------->| | | | | | | | |AA-Request | | |NASREQ-Payload | | |Auth-Request-Type=AUTHORIZE_ONLY | |QoS-Resources(QoS-Desired) | | +----------------------------->| | | | | | AA-Answer| | | Result-Code=DIAMETER_SUCCESS| | | (authorization AVPs)| | | QoS-Resources(QoS-Authorized)| | |<-----------------------------+ | | | Figure 14: Example of a Server-initiated Re-Authorization Procedure 5.5. Diameter Credit Control with QoS Information In this case the User is charged as soon as the Service Element (CC client) receives the service request. In this case the client uses the "QoS-Desired" QoS-Semantics parameter in the QoS-Resources AVP that it sends to the Accounitng server. The server responds with a "QoS-Available" QoS-Semantics parameter in the QoS-Resources AVP Korhonen, et al. Expires May 21, 2008 [Page 12] Internet-Draft QoS Attributes for Diameter November 2007 Service Element End User (CC Client) B CC Server | | | | |(1) Service Request | | | |-------------------->| | | | |(2) CCR (event, DIRECT_DEBITING,| | | QoS-Resources[QoS-desired]) | | |-------------------------------->| | |(3) CCA (Granted-Units, QoS- | | | Resources[QoS-Authorized]) | | |<--------------------------------| |(4) Service Delivery | | | |<--------------------| | | |(5) Begin service | | | |<------------------------------------>| | | | | | . . . . . . . . Figure 15: Example for a One-Time Diameter Credit Control Charging Event 6. Acknowledgments We would like to thank Victor Fajardo, Tseno Tsenov, Robert Hancock, Jukka Manner, Cornelia Kappler, Xiaoming Fu, Frank Alfano, Avi Lior, Tolga Asveren, Mike Montemurro, Glen Zorn, Avri Doria, Dong Sun, Tina Tsou, Pete McCann, Georgios Karagiannis and Elwyn Davies for their comments. 7. IANA Considerations This specification requests IANA to assignment of new AVPs from the AVP Code namespace defined in RFC 3588 [RFC3588]. Section 3 lists the newly defined AVPs. IANA is requested to allocate a registry for the QoS-Semantics. The following values are allocated by this specification. (0): QoS-Desired (1): QoS-Available (2): QoS-Reserved (3): Minimum-QoS (4): QoS-Authorized A specification is required to add a new value to the registry. A Korhonen, et al. Expires May 21, 2008 [Page 13] Internet-Draft QoS Attributes for Diameter November 2007 standards track document is required to depreciate, delete, or modify existing values. IANA is requested to allocate a registry for the QoS-Flow-State. The following values are allocated by this specification. Value | Name ------+------------------------------------------------------------ 0 | QOS_FLOW_STATE_PENDING A specification is required to add a new value to the registry. A standards track document is required to depreciate, delete, or modify existing values. 8. Security Considerations This document describes the extension of Diameter for conveying Quality of Service information. The security considerations of the Diameter protocol itself have been discussed in RFC 3588 [RFC3588]. Use of the AVPs defined in this document MUST take into consideration the security issues and requirements of the Diameter Base protocol. 9. References 9.1. Normative References [I-D.ietf-dime-qos-parameters] Korhonen, J. and H. Tschofenig, "Quality of Service Parameters for Usage with the AAA Framework", draft-ietf-dime-qos-parameters-01 (work in progress), September 2007. [I-D.ietf-radext-filter-rules] Congdon, P., "RADIUS Attributes for Filtering and Redirection", draft-ietf-radext-filter-rules-03 (work in progress), July 2007. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3588] Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J. Arkko, "Diameter Base Protocol", RFC 3588, September 2003. [RFC4005] Calhoun, P., Zorn, G., Spence, D., and D. Mitton, "Diameter Network Access Server Application", RFC 4005, August 2005. Korhonen, et al. Expires May 21, 2008 [Page 14] Internet-Draft QoS Attributes for Diameter November 2007 9.2. Informative References [I-D.ietf-dime-diameter-qos] Zorn, G., "Diameter Quality of Service Application", draft-ietf-dime-diameter-qos-01 (work in progress), July 2007. Authors' Addresses Jouni Korhonen (editor) TeliaSonera Teollisuuskatu 13 Sonera FIN-00051 Finland Email: jouni.korhonen@teliasonera.com Hannes Tschofenig Nokia Siemens Networks Otto-Hahn-Ring 6 Munich, Bavaria 81739 Germany Email: Hannes.Tschofenig@nsn.com URI: http://www.tschofenig.com Mayutan Arumaithurai University of Goettingen Email: mayutan.arumaithurai@gmail.com Mark Jones Bridgewater Systems 303 Terry Fox Drive Ottawa, Ontario K2K 3J1 Canada Email: mark.jones@bridgewatersystems.com Korhonen, et al. Expires May 21, 2008 [Page 15] Internet-Draft QoS Attributes for Diameter November 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). Korhonen, et al. Expires May 21, 2008 [Page 16]