Diameter Maintenance and                                K. Carlberg, Ed.
Extensions (DIME)                                                    G11
Internet-Draft                                                 T. Taylor
Intended status: Standards Track                     Huawei Technologies
                                                           July 5,
                                                            Oct 31, 2011

                Diameter Priority Attribute Value Pairs
                  draft-ietf-dime-priority-avps-04.txt
                  draft-ietf-dime-priority-avps-05.txt

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Abstract

   This document defines Attribute-Value Pair (AVP) containers for various
   priority parameters for use with Diameter and the AAA framework.  The
   parameters themselves are defined in several different protocols that
   operate at either the network or application layer.

1.  Introduction

   This document defines a number of Attribute-Value Pairs (AVP) that can
   be used within the Diameter protocol [I-D.ietf-dime-rfc3588bis] to
   convey a specific set of priority parameters.  These parameters are
   specified in other documents, but are briefly described below.  The
   corresponding AVPs defined in Section 3 are an extension to those
   defined in [RFC5866].  We note that all the priority fields associated
   with the AVPs defined in this document are extensible and allow for
   additional values beyond what may have already been defined or
   registered with IANA.

   Priority influences the distribution of resources.  This influence may
   be probabilistic, ranging between (but not including) 0% and 100%, or it
   may be 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 with 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 packet.

   Another example of how prioritization can be realized is articulated in
   Appendix A.3 (the priority by-pass model) of
   [I-D.ietf-tsvwg-emergency-rsvp].  In this case, prioritized flows may
   gain access to resources that are never shared with non-prioritized
   flows.

1.1  Other Priority-Related AVPs

   3rd Generation Partnership Project (3GPP) has defined several Diameter
   AVPs that support prioritization of sessions.  The following AVPs are
   intended to be used for priority services (e.g., Multimedia Priority
   Service):

     - Reservation-Priority AVP as defined in [ETSI]
     - MPS-Identifier AVP as defined in [3GPPa]
     - Priority-Level AVP (as part of the Allocation Retention Priority
       AVP) as defined in [3GPPb]

     - Session-Priority AVP as defined in [3GPPc][3GPPd]

   Both the Reservation-Priority AVP and the Priority-Level AVP can carry
   priority levels associated with a session initiated by a user.  We note
   that these AVPs are defined from the allotment set aside for 3GPP for
   Diameter-based interfaces. 3GPP has also defined other priority
   information for use on non-Diameter based interfaces.  However, this
   work is not relevant to the present document.  The AVPs defined by 3GPP
   are to be viewed as private implementations operating within a walled
   garden.

2.  Terminology and Abbreviations

   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 RFC2119 [RFC2119].

3.  Priority Parameter Encoding

   This section defines a set of priority AVPs.  This set is for use with
   the DIAMETER QoS application [RFC5866] and represents a continuation of
   the list of AVPs defined in [RFC5624].  The syntax notation used is that
   of [I-D.ietf-dime-rfc3588bis].

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.  These AVPs are
   derived from the corresponding priority fields specified in the Signaled
   Preemption Priority Policy Element [RFC3181] of RSVP [RFC2205].  The
   Defending-Priority is set when the reservation has been admitted.  The
   Preemption-Priority of a newly requested reservation is compared with
   the Defending Priority of a previously admitted flow.  The actions taken
   based upon the result of this comparison are 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 Unsigned16.
   Higher values represent higher priority.  The value encoded in this AVP
   is the same as the preemption priority value that would be encoded in
   the signaled preemption priority policy element.

3.1.2.  Defending-Priority AVP

   The Defending-Priority AVP (AVP Code TBD) is of type Unsigned16.  Higher
   values represent higher priority.  The value encoded in this AVP is the
   same as the defending priority value that would be encoded in the
   signaled preemption priority policy element.

3.2.  Admission-Priority AVP

   The Admission-Priority AVP (AVP Code TBD) is of type Unsigned8. The
   admission priority of the flow is used to increase the probability of
   session establishment for 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 5.1 of
   [I-D.ietf-tsvwg-emergency-rsvp].

3.3. SIP-Resource-Priority AVP

   The SIP-Resource-Priority AVP is a grouped AVP consisting of two AVPs,
   the SIP-Resource-Priority-Namespace and the SIP-Resource- Priority-Value
   AVP, which are derived from the corresponding optional header fields in
   [rfc4412].

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

3.3.1. SIP-Namespace AVP

   The SIP-Resource-Priority-Namespace AVP (AVP Code TBD) is of type
   UTF8String. This AVP contains a string that identifies a unique ordered
   set of priority values as described in [rfc4412].

3.3.2 SIP-Resource-Priority-Value AVP

   The SIP-Resource-Priority-Namespace AVP (AVP Code TBD) is of type
   UTF8String.  This AVP contains a string (i.e., a Namespace entry) that
   identifies a set of priority values unique to the Namespace.  Examples
   of Namespaces and corresponding sets of priorities are found in
   [rfc4412].

3.4.  Application-Level-Resource-Priority AVP

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

     Application-Level-Resource-Priority  ::= < AVP Header: TBD >
                                     { ALRP-Namespace }
                                     { ALRP-Value }

   A description of the semantics of the parameter values can be found in
   [RFC4412] and in [I-D.ietf-tsvwg-emergency-rsvp].  The registry set up
   by [RFC4412] provided string values for both the priority namespace and
   the priority values associated with that namespace.
   [I-D.ietf-tsvwg-emergency-rsvp] modifies that registry to assign
   numerical values to both the namespace identifiers and the priority
   values within them.  Consequently, SIP-Resource-Priority and
   Application-Level-Resource-Priority AVPs convey the same priority
   semantics, but with differing syntax.  In the former case, an
   alpha-numeric encoding is used, while the latter case is constrained to
   a numeric-only value.

3.4.1.  ALRP-Namespace AVP

   The ALRP-Namespace AVP (AVP Code TBD) is of type Unsigned16.  This AVP
   contains a numerical value identifying the namespace of the
   application-level resource priority as described in
   [I-D.ietf-tsvwg-emergency-rsvp].

3.4.2.  ALRP-Value AVP

   The ALRP-Priority AVP (AVP Code TBD) is of type Unsigned8.  This AVP
   contains the priority value within the ALRP-Namespace, as described in
   [I-D.ietf-tsvwg-emergency-rsvp].

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  |
    |SIP-Resource-Priority                  TBD  3.3       Grouped     |
    |SIP-Namespace                          TBD  3.3.1     UTF8String  |
    |SIP-Value                              TBD  3.3.2     UTF8String  |
    |Application-Level-Resource-Priority    TBD  3.4       Grouped     |
    |ALRP-Namespace                         TBD  3.4.1     Unsigned32  |
    |ALRP-Value                             TBD  3.4.2     Unsigned32  |
    +------------------------------------------------------------------+

4.2.  QoS Profile

   IANA is requested to allocate a new value from the Authentication,
   Authorization, and Accounting (AAA) Parameters/QoS Profile registry
   defined in [RFC5624] for the QoS profile defined in this document. The
   name of the profile is "Resource priority parameters".

5.  Security Considerations

   This document describes the an extension of Diameter for conveying Quality of Service information.
   information, and therefore follows the same security considerations of
   the Diameter QoS Application [RFC5866].  The values placed in the AVPs
   are not changed by this draft, nor are they changed in the Diameter QoS
   application.  The consequences of changing values in the Priority
   AVPs may result in an allocation of additional or less resources.  If local
   policy exists and values placed in the AVPs do not have integrity protection
   (e.g., the use of S/MIME with the SIP RPH, or an INTEGRITY object within
   a POLICY_DATA object), then changes and their consequences may occur.
   Otherwise, integrity protected values SHOULD be ignored with appropriate
   protocol specific error messages sent back upstream.  Note that we do not
   use the term "MUST be ignored"  because local policy of an administrative
   domain associated with other protocols acts as the final arbiter.

   The security considerations of the Diameter protocol itself have been are discussed
   in [I-D.ietf-dime-rfc3588bis].  Use of the AVPs defined in this document
   MUST take into consideration the security issues and requirements of the
   Diameter base protocol.

   The authors also recommend that readers should familiarize themselves
   with the security considerations of the various protocols listed in the
   Normative References listed below. References.  This is because values placed in the AVPs defined
   in this draft are set/changed by other protocols.

6.  Acknowledgements

   We would like to thank Lionel Morand, Janet Gunn, Piers O'Hanlon for the
   commenst on the draft, and 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.

7.  References
7.1.  Normative References

   [I-D.ietf-dime-rfc3588bis]
          Fajardo, V., Arkko, J., Loughney, J., and G. Zorn,
          "Diameter Base Protocol", draft-ietf-dime-rfc3588bis-26
          (work in progress), January 2011.

   [I-D.ietf-tsvwg-emergency-rsvp]
          Faucheur, F., Polk, J., and K. Carlberg, "Resource
          ReSerVation Protocol (RSVP) Extensions for Emergency
          Services", draft-ietf-tsvwg-emergency-rsvp-14 (work in
          progress), Nov 2009.

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

   [RFC2205] Braden, B., et. al., "Resource ReSerVation Protocol (RSVP)
             -- Version 1 Functional Specification", RFC 2205, September
             1997

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

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

   [RFC5624] Korhonen, J., Tschofenig, H., and E. Davies, "Quality of
            Service Parameters for Usage with Diameter", RFC 5624,
            Aug 2009.

   [RFC5866] Sun, D., et. al., "Diameter Quality-of-Service
             Application", RFC 5866, May 2010.

7.2.  Informative References

   [3GPPa] "TS 29.214: Policy and charging control over Rx reference
           point", 3GPP, March, 2011

   [3GPPb] "TS 29.212: Policy and charging control over Gx reference
           point", 3GPP, October, 2010

   [3GPPc] "TS 29.229: Cx and Dx interfaces based on the Diameter
           protocol; Protocol details", 3GPP, September, 2010

   [3GPPd] "TS 29.329: Sh interface based on the Diameter protocol;
           Protocol details", 3GPP, September, 2010

   [ETSI] "TS 183 017: Telecommunications and Internet Converged
          Services and Protocols for Advanced Networking (TISPAN);
          Resource and Admission Control", ETSI

Authors' Addresses
   Ken Carlberg (editor)          Tom Taylor
   G11                            Huawei Technologies
   1601 Clarendon Dr              1852 Lorraine Ave
   Arlington, VA 22209            Ottawa
   United States                  Canada

   Email: carlberg@g11.org.uk     Email: tom111.taylor@bell.net