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.

Copyright Notice

   Copyright (c) 2009 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents in effect on the date of
   publication of this document (http://trustee.ietf.org/license-info).
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.

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).

Table of Contents

   1. Introduction ....................................................2
   2. Terminology .....................................................2
   3. Diameter ITU-T Rw Policy Enforcement Interface ..................3
   4. IANA Considerations .............................................3
      4.1. Application Identifier .....................................3
      4.2. Command Codes ..............................................4
      4.3. AVP Codes ..................................................4
   5. Security Considerations .........................................4
   6. Acknowledgements ................................................4
   7. References ......................................................5
      7.1. Normative References .......................................5
      7.2. Informative References .....................................5

1.  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].

2.  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.

3.  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].

4.  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.

4.1.  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


4.2.  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

4.3.  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.

5.  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].

6.  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.

7.  References

7.1.  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.

7.2.  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: dongsun@alcatel-lucent.com