Diameter Priority Attribute Value Pairs

Diameter Maintenance and                                K. Carlberg, Ed.
Extensions (DIME)                                                    G11
Internet-Draft                                             H. Tschofenig
Intended status: Standards Track                  Nokia Siemens Networks
                                                            Oct 19, 2009

                Diameter Priority Attribute Value Pairs

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   This document  defines  various  priority  parameters  for  use  with
   Diameter  and  the  AAA  framework.   These parameters are defined in
   several different protocols that operate at  either  the  network  or
   application layer.

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1.  Introduction

   This document defines a number of priority  parameters  that  can  be
   reused for conveying priority labeled information within the Diameter
   protocol  [RFC3588].   It  defines  an   initial   priority   profile
   containing  a  set  of  Diameter encoded Attribute Value Pairs (AVPs)
   described using a modified version of the Augmented Backus-Naur  Form
   (ABNF), see [RFC3588].  The data types are also taken from [RFC3588].

   Priority influences the distribution of  resources.   This  influence
   may be probabilistic ranging between (but not including) 0% and 100%,
   or it may be binary (in the form of a guarantee to either receive  or
   not receive the resource).

   The influence attributed to prioritization may also affect  QoS,  but
   it is not to be confused as QoS.  As an example, if packets of two or
   more  flows  are  contending   for   the   same   shared   resources,
   prioritization  helps  determine  which packet receives the resource.
   However, this allocation of resource does not correlate  directly  to
   any  specific delay or loss bounds that have been associated with the

   One can also argue that the lack of contention (or  congested  state)
   of  the shared resource implies that packets of flow(s) are forwarded
   at the same rate (minus a  constant  processing  overhead)  they  are
   received  with  no  appreciable  difference in QoS experienced by any

   A third example of how prioritization can be realized is  articulated
   in   Appendix  A.3  (the  priority  by-pass  model)  of  [draft.rsvp-
   priority-extension].  In  this  case,  prioritized  flows  may  grant
   access to resources that are never shared with non-prioritized flows.

2.  Terminology and Abbreviations

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL",  "SHALL  NOT",
   document are to be interpreted as described in RFC2119 [RFC2119].

3.  Priority Parameter Encoding

3.1.  Dual-Priority AVP

   The Dual-Priority AVP is a grouped AVP consisting of  two  AVPs,  the
   Preemption-Priority and the Defending-Priority AVP, which are derived
   from the corresponding priority fields in the Signaled Policy Element

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   [rfc3181]  of RSVP [rfc2205].  The Defending-Priority is set when the
   reservation has been admitted.  The Preemption-Priority  of  a  newly
   requested  reservation and is compared with the Defending Priority of
   a previously admitted flow.  Actions taken upon this comparison is  a
   function of local policy.

     Dual-Priority  ::= < AVP Header: TBD >
                  { Preemption-Priority }
                  { Defending-Priority }

3.1.1.  Preemption-Priority AVP

   The Preemption-Priority AVP (AVP Code TBD)  is  of  type  Unsigned32.
   Higher values represent higher priority.

3.1.2.  Defending-Priority AVP

   The Defending-Priority AVP (AVP Code  TBD)  is  of  type  Unsigned32.
   Higher values represent higher priority.

3.2.  Admission-Priority AVP

   The Admission-Priority AVP (AVP Code TBD) is of type Unsigned32.

   The admission control priority of  the  flow  used  to  increase  the
   probability  of  session  establishment  to  selected  flows.  Higher
   values represent higher priority.   A  given  admission  priority  is
   encoded  in  this  information  element  using the same value as when
   encoded in the admission priority parameter defined in Section 3.1 of

3.3.  ALRP AVP

   The Application-Level Resource Priority (ALRP) AVP is a  grouped  AVP
   consisting of two AVPs, the ALRP-Namespace and the ALRP-Priority AVP.

   A description of the semantic of the parameter values can be found in
   [RFC4412]  and  in  [I-D.ietf-tsvwg-emergency-rsvp].   The coding for
   parameter is as follows:

     ALRP  ::= < AVP Header: TBD >
               { ALRP-Namespace }
               { ALRP-Priority }

3.3.1.  ALRP-Namespace AVP

   The ALRP-Namespace AVP (AVP Code TBD) is of type Unsigned32.

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3.3.2.  ALRP-Priority AVP

   The  ALRP-Priority  AVP  (AVP  Code  TBD)  is  of  type   Unsigned32.
   [RFC4412]  defines  a  resource  priority  header and established the
   initial registry.  That registry was  later  extended  by  [I-D.ietf-


   The SIP-RPH AVP is a grouped AVP consisting of  two  AVPs,  the  SIP-
   Namespace   and  the  SIP-Value  AVP,  which  are  derived  from  the
   corresponding optional header fields in [rfc4412].  The SIP-Namespace
   identifies  a particular set of priorities.  The SIP-Value identifies
   a specific priority associated with the SIP-Namespace.

     SIP-RPH ::= <AVP Header:  TBD>                  {  SIP-Namespace  }
                     { SIP-Value }

3.4.1.  SIP-Namespace AVP

   The SIP-Namespace AVP (AVP Code TBD) is of type UTF8String.

3.4.2 SIP-Value AVP

   The SIP-Value AVP (AVP Code TBD) is of type UTF8String.

4.  IANA Considerations

4.1.  AVP Codes

   IANA is requested to allocate AVP codes for the following  AVPs  that
   are defined in this document.

    |                                       AVP  Section               |
    |AVP Name                               Code Defined   Data Type   |
    |Dual-Priority                          TBD  3.1       Grouped     |
    |Preemption-Priority                    TBD  3.1.1     Unsigned32  |
    |Defending-Priority                     TBD  3.1.2     Unsigned32  |
    |Admission-Priority                     TBD  3.2       Unsigned32  |
    |ALRP                                   TBD  3.3       Grouped     |
    |ALRP-Namespace                         TBD  3.3.1     Unsigned32  |
    |ALRP-Priority                          TBD  3.3.2     Unsigned32  |
    |SIP-RPH                                TBD  3.4       Grouped     |
    |SIP-Namespace                          TBD  3.4.1     UTF8String  |
    |SIP-Value                              TBD  3.4.2     UTF8String  |

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4.2.  QoS Profile

   IANA is requested to allocate a new value from the  registry  defined
   in [I-D.ietf-dime-qos-parameters] for the QoS profile defined in this

5.  Examples

              +--------+              +--------+
              |Diameter|              |  SIP   |
              | server |              | server |
              +--------+              +--------+
                  |                       |
                  |                       |
                  |                       |
           1. SIP INVITE w/ RPH           |
                  | 2. MAR w/ SIP-RPH AVP |
                  | 3. MAA.               |
                  |---------------------->| 8. SIP INVITE
                  |                       |---------------->
                  |                       | 9. SIP 200 (OK)
                 10. SIP 200 (OK)         |<----------------
                  |                       |

6.  Security Considerations


7.  Acknowledgements

   We  would  like  to  thank  Lars  Eggert,  Jan  Engelhardt,  Francois
   LeFaucheur,  John  Loughney, An Nguyen, Dave Oran, James Polk, Martin
   Stiemerling, and Magnus Westerlund  for  their  help  with  resolving
   problems  regarding  the  Admission  Priority and the ALRP parameter.
   Additionally, we would like to thank Martin Dolly  and  Viqar  Shaikh
   for their feedback.

8.  References

8.1.  Normative References

           Korhonen, J., Tschofenig, H., and E. Davies, "Quality of
           Service Parameters for Usage with Diameter",

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           draft-ietf-dime-qos-parameters-11 (work in progress)
           May 2009.

           Faucheur, F., Polk, J., and K. Carlberg, "Resource
           ReSerVation Protocol (RSVP) Extensions for Emergency
           Services", draft-ietf-tsvwg-emergency-rsvp-12 (work in
           progress), May 2009.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC3181]  Herzog, S., "Signaled Preemption Priority Policy Element",
              RFC 3181, October 2001.

   [RFC3588]  Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J.
              Arkko, "Diameter Base Protocol", RFC 3588, September 2003.

   [RFC4124]  Le Faucheur, F., "Protocol Extensions for Support of
              Diffserv-aware MPLS Traffic Engineering", RFC 4124,
              June 2005.

   [RFC4412]  Schulzrinne, H. and J. Polk, "Communications Resource
              Priority for the Session Initiation Protocol (SIP)",
              RFC 4412, February 2006.

8.2.  Informative References

              Bader, A., Kappler, C., and D. Oran, "QoS NSLP QSPEC
              Template", draft-ietf-nsis-qspec-21 (work in progress),
              November 2008.

   [RFC3564]  Le Faucheur, F. and W. Lai, "Requirements for Support of
              Differentiated Services-aware MPLS Traffic Engineering",
              RFC 3564, July 2003.

Authors' Addresses

   Ken Carlberg (editor)          Hannes Tschofenig
   G11                            Nokia Siemens Networks
   1601 Clarendon Dr              Linnoitustie 6 Espoo 02600
   Arlington, VA 22209            Finland
   United States                  Phone: +358 (50) 4871445

   Email: carlberg@g11.org.uk     Email: Hannes.Tschofenig@gmx.net

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