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).
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
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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.
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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.
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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.
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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
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