RFC5431

Network Working Group D. Sun Request for Comments: 5431 Alcatel-Lucent Category: Informational March 2009

   Diameter ITU-T Rw Policy Enforcement Interface Application

Status of This Memo

This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited.

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Abstract

This document describes the need for a new pair of IANA Diameter Command Codes to be used in a vendor-specific new application, namely for the ITU-T Rec. Q.3303.3 - Rw interface used to send a request/ response for authorizing network Quality of Service (QoS) resources and policy enforcement in a network element, as one of the recommendations of the International Telecommunication Union - Telecommunication Standardization Sector (ITU-T).

Introduction

This document summarizes the use of Diameter codes in a newly defined realization of a specification for authorizing network QoS resources and policy enforcement [Q.3303.3]. A new pair of Command Codes have been assigned by IANA. This document summarizes the uses of newly defined Diameter codes (Command Codes, AVP, vendor-specific application id). When combined with the Diameter Base protocol, this application's specification [Q.3303.3] satisfies the requirements of [Y.2111] of the International Telecommunication Union - Telecommunication Standardization Sector (ITU-T) to send a request and receive a response for controlling the policy enforcement.

The Diameter realization of this application assumes the use of the Diameter Base protocol, as per RFC 3588, and extends it only for a specific application using a vendor-id (ITU-T), a vendor-specific application ID (16777256), a new Command Code (315), and new attribute-value pairs (AVPs), which are defined in the vendor- specific namespace.

This application is used to authorize network QoS resources and policy enforcement (including the amount of bandwidth, QoS class, and traffic flow processing) as an extension of the Diameter application RFC4006. The request is based on the Diameter extensibility discussions in the DIME WG that led to the conclusion that it is better to define new Command Codes whenever the ABNF of a command is modified by adding, removing, or semantically changing a required AVP in order to avoid interoperability problems. The document is utilizing authorization and accounting functionality, and the entire exchange is related to users utilizing applications that require QoS treatment. This approach is consistent with the practice and experience gained since the publication of RFC3588 (see for example RFC5224), which is now under revision by the DIME Working Group who will provide a revised set of recommendations and procedures for IANA considerations [DIME].

Terminology

In the base Diameter specification RFC3588, Section 1.4 defines most of the terminology used in this document. Additionally, the terms and acronyms defined in Section 3 and Section 4 of [Q.3303.3] are used in this document.

Diameter ITU-T Rw Policy Enforcement Interface

The Rw interface is used for information exchange to apply policy decisions between the Policy Decision Point (PDP, i.e., in the ITU-T term, Policy Decision Functional Entity (PD-FE)) and the Policy Enforcement Point (PEP, i.e., in the ITU-T term, Policy Enforcement Functional Entity (PE-FE)).

The interface allows the PDP to push the authorized admission decisions to the PEP. It also allows the PEP to request the authorization of admission decisions from the PDP when path-coupled resource reservation mechanisms are in use. The main information conveyed by the Rw interface is:

o Resources reservation and/or allocation requests for media flows;

o QoS handling requests such as packet marking and policing;

o Gate control (opening/closing) requests for a media flow;

o NAPT and NAT traversal requests for the necessary address mapping

  information;

o Resource usage information requests and reports for media flows.

The detailed descriptions of the Diameter Policy Enforcement interface ITU-T Rw can be found in Section 5 of [Q.3303.3].

IANA Considerations

This section provides guidance to the Internet Assigned Numbers Authority (IANA) regarding registration of values related to the Diameter protocol, in accordance with BCP 26 RFC5226.

This document defines values in the namespaces that have been created and defined in RFC3588. The IANA Considerations section of that document details the assignment criteria. Values assigned in this document, or by future IANA action, must be coordinated within this shared namespace.

Application Identifier

A vendor-specific application ID (16777256) for the application of [Q.3303.3] has been assigned by the IANA.

Registry: ID values Name Reference

---

16777256 ITU-T Rw 7.2.1 of ITU-T Q.3303.3

Command Codes

IANA has allocated Command Code values for the following commands defined in Section 7.4 of [Q.3303.3] from the Command Code namespace defined in RFC3588.

Registry: Code Value Name Reference

---

315 Policy-Install-Request(PIR) 7.4.1 of ITU-T Q.3303.3 315 Policy-Install-Answer (PIA) 7.4.2 of ITU-T Q.3303.3

AVP Codes

The values 1010~1018 are assigned by the ITU-T to the following AVPs within the ITU-T vendor-ID 11502 namespace: PI-Request-Type AVP, PI- Request-Number AVP, Traffic-Descriptor-UL AVP, Traffic-Descriptor-DL AVP, Maximum-Burst-Size AVP, Committed-Data-Rate AVP, Committed- Burst-Size AVP, Excess-Burst-Size, Removal-Cause AVP.

See Table 1/Q.3303.3 in Section 7.3.1 of [Q.3303.3] for detailed information on AVP codes, value types, and flag rules.

Security Considerations

This document describes the Diameter Policy Enforcement Application. It builds on top of the Diameter Base protocol and the same security considerations described in RFC3588 are applicable to this document. No further extensions are required beyond the security mechanisms offered by RFC3588.

Acknowledgements

The author would like to thank Dan Romascanu, Hannes Tschofenig, and Tina Tsou for their help and support. Finally, the author would like to thank Alcatel-Lucent, as most of the effort put into this document was done while he was in their employ.

References

Normative References

[Q.3303.3] ITU-T Recommendation Q.3303.3, "Resource control protocol

           no. 3 (rcp3): Protocol at the Rw interface between the
           Policy Decision Physical Entity (PD-PE) and the Policy
           Enforcement Physical Entity (PE-PE): Diameter", 2008.

RFC3588 Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J.

           Arkko, "Diameter Base Protocol", RFC 3588,
           September 2003.

Informative References

[DIME] Fajardo, V., Arkko, J., Loughney, J., and G. Zorn,

           "Diameter Base Protocol", Work in Progress,
           November 2008.

RFC4006 Hakala, H., Mattila, L., Koskinen, J-P., Stura, M., and

           J. Loughney, "Diameter Credit-Control Application",
           RFC 4006, August 2005.

RFC5224 Brenner, M., "Diameter Policy Processing Application",

           RFC 5224, March 2008.

RFC5226 Narten, T. and H. Alvestrand, "Guidelines for Writing an

           IANA Considerations Section in RFCs", BCP 26, RFC 5226,
           May 2008.

[Y.2111] ITU-T Recommedation Y.2111, "Resource and admission

           control functions in Next Generation Networks",
           September 2006.

Author's Address

Dong Sun Alcatel-Lucent 600 Mountain Ave Murray Hill, NJ 07974 USA

Phone: +1 908 582 2617 EMail: [email protected]