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RFC 5866

 
 
 

Diameter Quality-of-Service Application

Part 3 of 3, p. 34 to 51
Prev RFC Part

 


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6.  QoS Application State Machine

   The QoS application defines its own state machine that is based on
   the authorization state machine defined in Section 8.1 of the
   Diameter base protocol ([RFC3588]).  The QoS state machine uses its
   own messages, as defined in Section 5, and QoS AVPs, as defined in
   Section 7.

6.1.  Supplemented States for Push Mode

   Using the Diameter base protocol state machine as a basis, the
   following states are supplemented to the first two state machines in
   which the session state is maintained on the server.  These MUST be
   supported in any QoS application implementations in support of
   server-initiated Push mode (see Section 4.2.2).

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   The following states are supplemented to the state machine on the
   server when state is maintained on the client, as defined in Section
   8.1 of the Diameter base protocol[RFC3588]:

                                 SERVER, STATEFUL
         State     Event                          Action     New State
         -------------------------------------------------------------
         Idle      An application or local        Send        Pending
                   event triggers an initial      QIR initial
                   QoS request to the server      request

         Pending   Received QIA with a failed     Clean up    Idle
                   Result-Code

         Pending   Received QIA with Result-Code  Update      Open
                   = SUCCESS                      session
         Pending   Error in processing received   Send        Discon
                   QIA with Result-Code = SUCCESS ASR

   The following states are supplemented to the state machine on the
   client when state is maintained on the server, as defined in Section
   8.1 of the Diameter base protocol [RFC3588]:

                                 CLIENT, STATEFUL
         State     Event                          Action     New State
         -------------------------------------------------------------
         Idle      QIR initial request            Send         Open
                   received and successfully      QIA initial
                   processed                      answer,
                                                  reserve
                                                  resources

         Idle      QIR initial request            Send         Idle
                   received but not               QIA initial
                   successfully processed         answer with
                                                  Result-Code
                                                  != SUCCESS

7.  QoS Application AVPs

   Each of the AVPs identified in the QoS-Authorization-Request/Answer
   and QoS-Install-Request/Answer messages and the assignment of their
   value(s) is given in this section.

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7.1.  Reused Base Protocol AVPs

   The QoS application uses a number of session management AVPs, defined
   in the base protocol ([RFC3588]).

   Attribute Name                AVP Code     Reference [RFC3588]
   Origin-Host                   264          Section 6.3
   Origin-Realm                  296          Section 6.4
   Destination-Host              293          Section 6.5
   Destination-Realm             283          Section 6.6
   Auth-Application-Id           258          Section 6.8
   Result-Code                   268          Section 7.1
   Auth-Request-Type             274          Section 8.7
   Session-Id                    263          Section 8.8
   Authorization-Lifetime        291          Section 8.9
   Auth-Grace-Period             276          Section 8.10
   Session-Timeout                27          Section 8.13
   User-Name                       1          Section 8.14

   The Auth-Application-Id AVP (AVP Code 258) is assigned by IANA to
   Diameter applications.  The value of the Auth-Application-Id for the
   Diameter QoS application is 9.

7.2.  QoS Application-Defined AVPs

   This document reuses the AVPs defined in Section 4 of [RFC5777].

   This section lists the AVPs that are introduced specifically for the
   QoS application.  The following new AVPs are defined: Bound-Auth-
   Session-Id and the QoS-Authorization-Data AVP.

   The following table describes the Diameter AVPs newly defined in this
   document for use with the QoS Application, their AVP code values,
   types, possible flag values, and to determine whether the AVP may be
   encrypted.

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                                                  +-------------------+
                                                  |    AVP Flag rules |
   +----------------------------------------------|----+--------+-----+
   |                       AVP  Section           |    |    SHLD| MUST|
   | Attribute Name        Code Defined Data Type |MUST|     NOT|  NOT|
   +----------------------------------------------+----+--------+-----+
   |QoS-Authorization-Data 579    7.2  OctetString| M  |        |  V  |
   |Bound-Auth-Session-Id  580    7.2  UTF8String | M  |        |  V  |
   +----------------------------------------------+----+--------+-----+
   |M - Mandatory bit. An AVP with the "M" bit set and its value MUST |
   |    be supported and recognized by a Diameter entity in order for |
   |    the message, which carries this AVP, to be accepted.          |
   |V - Vendor-specific bit that indicates whether the AVP belongs to |
   |    an address space.                                              |
   +------------------------------------------------------------------+

   QoS-Authorization-Data
      The QoS-Authorization-Data AVP (AVP Code 579) is of type
      OctetString.  It is a container that carries application-session
      or user-specific data that has to be supplied to the AE as input
      to the computation of the authorization decision.

   Bound-Authentication-Session-Id
      The Bound-Authentication-Session AVP (AVP Code 580) is of type
      UTF8String.  It carries the ID of the Diameter authentication
      session that is used for the network access [RFC4005].  It is used
      to tie the QoS authorization request to a prior authentication of
      the end-host done by a co-located application for network access
      authentication ([RFC4005]) at the QoS NE.

8.  Accounting

   An NE MAY start an accounting session by sending an Accounting-
   Request (ACR) message after successful QoS reservation and activation
   of the data flow (see Figures 6 and 7).  After every successful re-
   authorization procedure (see Figures 8 and 9), the NE MAY initiate an
   interim accounting message exchange.  After successful session
   termination (see Figures 10 and 11), the NE may initiate a final
   exchange of accounting messages for the termination of the accounting
   session and report final records for the use of the QoS resources
   reserved.  It should be noted that the two sessions (authorization
   and accounting) have independent management by the Diameter base
   protocol, which allows for finalizing the accounting session after
   the end of the authorization session.

   The detailed QoS accounting procedures are out of scope in this
   document.

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9.  Examples

9.1.  Example Call Flow for Pull Mode (Success Case)

   This section presents an example of the interaction between the end-
   host and Diameter QoS application entities using Pull mode.  The
   application-layer signaling is, in this example, provided using SIP.
   Signaling for a QoS resource reservation is done using the QoS NSIS
   Signaling Layer Protocol (NSLP).  The authorization of the QoS
   reservation request is done by the Diameter QoS application (DQA).

     End-Host                                 SIP Proxy  Correspondent
   requesting QoS                            (DQA Server)        Node
         |                                          |              |
       ..|....Application-layer SIP signaling.......|..............|..
       . |  Invite (SDP)                            |              | .
       . +.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.->              | .
       . |  100 Trying                              |              | .
       . <.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-+  Invite (SDP)| .
       . |                                          +-.-.-.....-.-.> .
       . |                                          |  180 SDP'    | .
       . |                                          <-.-.-.....-.-.+ .
       . |                                 +--------+--------+     | .
       . |                                 |Authorize session|     | .
       . |                                 |   parameters    |     | .
       . | 180 (Session parameters)        +--------+--------+     | .
       . <.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-+              | .
       ..|..........................................|... ..........|..
         |                                          |              |
         |           +------------+                 |              |
         |           |     NE     |                 |              |
         |           |(DQA Client)|                 |              |
         |           +------+-----+                 |              |
         |                  |                       |              |
         |QoS NSLP Reserve  |                       |              |
         +------------------> QAR                   |              |
         | (POLICY_DATA>v   +- - - - -<<AAA>>- - - ->              |
         |  QSPEC)  v   >===>(Destination-Host,     |              |
         |      v   >=======>QoS-Authorization-Data++------------+ |
         |      >===========>QoS-Resources)        |Authorize    | |
         |                  |                      |QoS resources| |
         |                  |                      ++------------+ |
         |                  | QAA                   |              |
         |                  <- - - - -<<AAA>>- - - -+              |
         |                  |(Result-Code,          |              |
         |                  |QoS-Resources,         |              |
         |                  |Authorization-Lifetime)|              |

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         |        +---------+--------+              |              |
         |        |Install QoS state1|              |              |
         |        |+ Authz  session  |              |              |
         |        +---------+--------+              |              |
         |                  |QoS NSLP Reserve                      |
         |                  +---------------..............--------->
         |                  |                                      |
         |                  |                     QoS NSLP Response|
         |QoS NSLP Response <---------------..............---------+
         <------------------+                                      |
         |                  |                        QoS NSLP Query|
         |QoS NSLP Query    <---------------..............---------+
         <------------------+                                      |
         |QoS NSLP Reserve  |                                      |
         +------------------> QAR                   |              |
         |                  +- - - - -<<AAA>>- - - ->              |
         |                  |                   +---+---------+    |
         |                  |                   |Authorize    |    |
         |                  |                   |QoS resources|    |
         |                  | QAA               +---+---------+    |
         |                  <- - - - -<<AAA>>- - - -+              |
         |        +---------+--------+              |              |
         |        |Install QoS state2|                             |
         |        |+ Authz  session  |                             |
         |        +---------+--------+                             |
         |                  |  QoS NSLP Reserve                    |
         |                  +---------------..............--------->
         |                  |                     QoS NSLP Response|
         |QoS NSLP Response <---------------..............---------+
         <------------------+                                      |
         |                  |                                      |
         /------------------+--Data Flow---------------------------\
         \------------------+--------------------------------------/
         |                  |                                      |

         .-.-.-.-.  SIP signaling
         ---------  QoS NSLP signaling
         - - - - -  Diameter QoS Application messages
         =========  Mapping of objects between QoS and AAA protocol

             Figure 12: QoS Authorization Example - Pull Mode

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   The communication starts with SIP signaling between the two endpoints
   and the SIP proxy for negotiation and authorization of the requested
   service and its parameters (see Figure 12).  As a part of the
   process, the SIP proxy verifies whether the user at Host A is
   authorized to use the requested service (and potentially the ability
   to be charged for the service usage).  Negotiated session parameters
   are provided to the end-host.

   Subsequently, Host A initiates a QoS signaling message towards Host
   B. It sends a QoS NSLP Reserve message, in which it includes
   description of the required QoS (QSPEC object) and authorization data
   for negotiated service session (part of the POLICY_DATA object).
   Authorization data includes, as a minimum, the identity of the AE
   (e.g., the SIP proxy) and an identifier of the application-service
   session for which QoS resources are requested.

   A QoS NSLP reserve message is intercepted and processed by the first
   QoS-aware Network Element.  The NE uses the Diameter QoS application
   to request authorization for the received QoS reservation request.
   The identity of the AE (in this case, the SIP server that is co-
   located with a Diameter server) is put into the Destination-Host AVP,
   any additional session authorization data is encapsulated into the
   QoS-Authorization-Data AVP, and the description of the QoS resources
   is included into the QoS-Resources AVP.  These AVPs are included into
   a QoS Authorization Request message, which is sent to the AE.

   A QAR message will be routed through the AAA network to the AE.  The
   AE verifies the requested QoS against the QoS resources negotiated
   for the service session and replies with a QoS-Authorization-Answer
   (QAA) message.  It carries the authorization result (Result-Code AVP)
   and the description of the authorized QoS parameters (QoS-Resources
   AVP), as well as duration of the authorization session
   (Authorization-Lifetime AVP).

   The NE interacts with the Traffic Control function and installs the
   authorized QoS resources and forwards the QoS NSLP reserve message
   farther along the data path.  Moreover, the NE may serve as a
   signaling proxy and process the QoS signaling (e.g., initiation or
   termination of QoS signaling) based on the QoS decision received from
   the Authorizing Entity.

9.2.  Example Call Flow for Pull Mode (Failure Case)

   This section repeats the scenario outlined in Section 9.1; however,
   in this case, we show a session authorization failure instead of
   success.  Failures can occur in various steps throughout the protocol
   execution, and in this example, we assume that the Diameter QAR
   request processed by the Diameter server leads to an unsuccessful

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   result.  The QAA message responds, in this example, with a permanent
   error "DIAMETER_AUTHORIZATION_REJECTED" (5003) set in the Result-Code
   AVP.  When the NE receives this response, it discontinues the QoS
   reservation signaling downstream and provides an error message back
   to the end-host that initiated the QoS signaling request.  The QoS
   NSLP response signaling message would in this case carry an INFO_SPEC
   object indicating the permanent failure as "Authorization failure"
   (0x02).

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     End-Host                                 SIP Proxy  Correspondent
   requesting QoS                            (DQA Server)        Node

         |                                          |              |
       ..|...................SIP Signaling..........|..............|..
       . |  Invite (SDP)                            |              | .
       . +.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.->              | .
       . |  100 Trying                              |              | .
       . <.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-+  Invite (SDP)| .
       . |                                          +-.-.-.....-.-.> .
       . |                                          |  180 SDP'    | .
       . |                                          <-.-.-.....-.-.+ .
       . |                                 +--------+--------+     | .
       . |                                 |Authorize session|     | .
       . |                                 |   parameters    |     | .
       . | 180 (Session parameters)        +--------+--------+     | .
       . <.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-+              | .
       ..|..........................................|... ..........|..
         |                                          |              |
         |           +------------+                 |              |
         |           |     NE     |                 |              |
         |           |(DQA Client)|                 |              |
         |           +------+-----+                 |              |
         |                  |                       |              |
         |QoS NSLP Reserve  |                       |              |
         +------------------> QAR                   |              |
         | (POLICY_DATA>v   +- - - - -<<AAA>>- - - ->              |
         |  QSPEC)  v   >===>(Destination-Host,     |              |
         |      v   >=======>QoS-Authorization-Data++------------+ |
         |      >===========>QoS-Resources)        |Authorize    | |
         |                  |                      |QoS resources| |
         |                  |                      ++------------+ |
         |                  | QAA                   |              |
         |                  <- - - - -<<AAA>>- - - -+              |
         |                  |(Result-Code = 5003)   |              |
         |                  |                       |              |
         |QoS NSLP Response |                       |              |
         |(with error 0x02) |                       |              |
         <------------------+                       |              |
         |                  |                       |              |
         |                  |                       |              |

         .-.-.-.-.  SIP signaling
         ---------  QoS NSLP signaling
         - - - - -  Diameter QoS Application messages
         =========  Mapping of objects between QoS and AAA protocol

      Figure 13: QoS Authorization Example - Pull Mode (Failure Case)

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9.3.  Example Call Flow for Push Mode

   This section presents an example of the interaction between the end-
   host and Diameter QoS application entities using Push mode.  The
   application-layer signaling is, in this example, provided using SIP.
   Signaling for a QoS resource reservation is done using the QoS NSLP.
   The authorization of the QoS reservation request is done by the
   Diameter QoS application (DQA).

    End-Host              NE                  SIP Proxy  Correspondent
  requesting QoS      (DQA Client)           (DQA Server)        Node

        |                  |                          |              |
      ..|..................|...SIP Signaling..........|..............|..
      . | Invite(SDP Offer)|                          |              | .
      . +.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.+-.-.-.-.-.-.->| .
      . |                  |                          |   180        | .
      . |<-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.+-.-.-.-.-.-.-.| .
      ..|.............................................|..............|..
        |                  |                +---------+-------------+|
        |                  |                |  Authorize Request    ||
        |                  |                |  Keep Session Data    ||
        |                  |                |/Authz-time,Session-Id/||
        |                  |                +---------+-------------+|
        |                  |                          |              |
        |                  |<-- - -- - QIR - -- - -- -+              |
        |                  |(Initial Request,Decision |              |
        |                  |(QoS-Resources,Authz-time)|              |
        |          +-------+---------+                |              |
        |          |Install QoS State|                |              |
        |          |       +         |                |              |
        |          | Authz  Session  |                |              |
        |          | /Authz-time/    |                |              |
        |          +-------+---------+                |              |
        |                  + - - -- - QIA - - - - - ->|              |
        |                  |     (Result-Code,        |              |
        |                  |      QoS-Resources)      |              |
        |                  |               +----------+------------+ |
        |                  |               |     Successful        | |
        |                  |               |     QoS Reservation   | |
        |                  |               +----------+------------+ |

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      ..|.............................................|..............|..
      . |                  |                          |              | .
      . |                  |                          |  200 OK (SDP)| .
      . |                  |                          <-.-.-.....-.-.+ .
      . |                  |                 +--------+-----------+  | .
      . |                  |                 |   Activate Session |  | .
      . |                  |                 |   Parameters       |  | .
      . |                  |                 +--------+-----------+  | .
      . | 200 (SDP)        |                          |              | .
      . <.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.+              | .
      ..|.............................................|..............|..
        |                  <- - - - - - RAR - - - - - +              |
        |        +---------+--------+                 |              |
        |        |Activate QoS State|                 |              |
        |        +---------+--------+                 |              |
        |                  +- - - - - - RAA - - - - - >              |
        |                  |                                         |
        /------------------+-----Data Flow---------------------------\
        \------------------+-----------------------------------------/
        |                  |                                         |

        .-.-.-.-.  SIP signaling
        - - - - -  Diameter QoS Application messages

             Figure 14: QoS Authorization Example - Push Mode

   The communication starts with SIP signaling between the two endpoints
   and the SIP proxy for negotiation and authorization of the requested
   service and its parameters (see Figure 14).  As a part of the
   process, the SIP proxy verifies whether the user at Host A is
   authorized to use the requested service (and potentially the ability
   to be charged for the service usage).

   A few implementation choices exist regarding the decision about when
   to initiate the QoS reservation.  [MMUSIC-MEDIA] discusses this
   aspect with a focus on firewalling.  In the example above, the DQA
   server is triggered to authorize the QoS request based on session
   parameters from the Session Description Protocol (SDP) payload.  It
   will use a QIR message to do so.  For this example message flow, we
   assume a two-stage commit, i.e., the SIP proxy interacts with the NE
   twice.  First, it only prepares the QoS reservation, and then, with
   the arrival of the 200 OK, the QoS reservation is activated.

   This example does not describe how the DQA server learns which DQA
   client to contact.  We assume pre-configuration in this example.  In
   any case, the address of the DQA client is put into the Destination-
   Host AVP, the description of the QoS resources is included into the

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   QoS-Resources AVP, and the duration of the authorization session is
   carried in the Authorization-Lifetime AVP.

   When the DQA client receives the QIR, it interacts with the Traffic
   Control function and reserves the authorized QoS resources
   accordingly.  At this point in time, the QoS reservation is not yet
   activated.

   When a 200 OK is returned, the DQA server may verify the accepted QoS
   against the pre-authorized QoS resources and send a Diameter RAR
   message to the DQA client in the NE for activating the installed
   policies and commit the resource allocation.

10.  IANA Considerations

   This section contains the namespaces that have either been created in
   this specification or had their values assigned to existing
   namespaces managed by IANA.

10.1.  AVP Codes

   IANA has allocated two AVP codes to the registry defined in
   [RFC3588]:

   Registry:
   AVP Code         AVP Name                      Reference
   -----------------------------------------------------------
     579        QoS-Authorization-Data           Section 7.2
     580        Bound-Auth-Session-Id            Section 7.2

10.2.  Application IDs

   IANA has allocated the following application ID from the registry
   defined in [RFC3588] (using the next available value from the
   7-16777215 range).

   Registry:
   ID values           Name                         Reference
   -----------------------------------------------------------
     9           Diameter QoS application           Section 5

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10.3.  Command Codes

   IANA has allocated command code values from the registry defined in
   [RFC3588].

   Registry:
   Code Value  Name                                Reference
   -----------------------------------------------------------
   326         QoS-Authorization-Request (QAR)     Section 5.1
   326         QoS-Authorization-Answer  (QAA)     Section 5.2
   327         QoS-Install-Request (QIR)           Section 5.3
   327         QoS-Install-Answer (QIA)            Section 5.4

11.  Security Considerations

   This document describes a mechanism for performing authorization of a
   QoS reservation at a third-party entity.  The Authorizing Entity
   needs sufficient information to make such an authorization decision
   and this information may come from various sources, including the
   application-layer signaling, the Diameter protocol (with its security
   mechanisms), policy information stored available with a AAA server,
   and a QoS signaling protocol.

   Below there is a discussion about considerations for the Diameter QoS
   interaction between an Authorizing Entity and a Network Element.
   Security between the Authorizing Entity and the Network Element has a
   number of components: authentication, authorization, integrity, and
   confidentiality.

   Authentication refers to confirming the identity of an originator for
   all datagrams received from the originator.  Lack of authentication
   of Diameter messages between the Authorizing Entity and the Network
   Element can seriously jeopardize the fundamental service rendered by
   the Network Element.  A consequence of not authenticating the message
   sender by the Network Element would be that an attacker could spoof
   the identity of a "legitimate" Authorizing Entity in order to
   allocate resources, change resource assignments, or free resources.
   The adversary can also manipulate the state at the Network Element in
   such a way that it leads to a denial-of-service attack by, for
   example, setting the allowed bandwidth to zero or allocating the
   entire bandwidth available to a single flow.

   A consequence of not authenticating the Network Element to an
   Authorizing Entity is that an attacker could impact the policy-based
   admission control procedure operated by the Authorizing Entity that
   provides a wrong view of the resources used in the network.  Failing
   to provide the required credentials should be subject to logging.

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   Authorization refers to whether a particular Authorizing Entity is
   authorized to signal a Network Element with requests for one or more
   applications, adhering to a certain policy profile.  Failing the
   authorization process might indicate a resource theft attempt or
   failure due to administrative and/or credential deficiencies.  In
   either case, the Network Element should take the proper measures to
   log such attempts.

   Integrity is required to ensure that a Diameter message has not been
   maliciously altered.  The result of a lack of data integrity
   enforcement in an untrusted environment could be that an imposter
   will alter the messages exchanged between a Network Entity and an
   Authorizing Entity potentially causing a denial of service.

   Confidentiality protection of Diameter messages ensures that the
   signaling data is accessible only to the authorized entities.  When
   signaling messages from the Application Server (via the Authorizing
   Entity towards the Network Element) traverse untrusted networks, lack
   of confidentiality will allow eavesdropping and traffic analysis.
   Additionally, Diameter QoS messages may carry authorization tokens
   that require confidentiality protection.

   Diameter offers security mechanisms to deal with the functionality
   demanded in the paragraphs above.  In particular, Diameter offers
   communication security between neighboring Diameter peers using
   Transport Layer Security (TLS) or IPsec.  Authorization capabilities
   are application specific and part of the overall implementation.

12.  Acknowledgements

   The authors would like to thank John Loughney and Allison Mankin for
   their input to this document.  In September 2005, Robert Hancock,
   Jukka Manner, Cornelia Kappler, Xiaoming Fu, Georgios Karagiannis,
   and Elwyn Davies provided a detailed review.  Robert also provided us
   with good feedback earlier in 2005.  Jerry Ash provided us review
   comments in late 2005/early 2006.  Rajith R provided some inputs to
   the document in early 2007.

   We would also like to thanks Alexey Melnikov, Adrian Farrel, and
   Robert Sparks for their IESG reviews.

13.  Contributors

   The authors would like to thank Tseno Tsenov and Frank Alfano for
   starting the Diameter Quality of Service work within the IETF, for
   their significant contributions and for being the driving force for
   the first few draft versions.

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14.  References

14.1.  Normative References

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

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

   [RFC4005]       Calhoun, P., Zorn, G., Spence, D., and D. Mitton,
                   "Diameter Network Access Server Application",
                   RFC 4005, August 2005.

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

   [RFC5777]       Korhonen, J., Tschofenig, H., Arumaithurai, M.,
                   Jones, M., and A. Lior, "Traffic Classification and
                   Quality of Service (QoS) Attributes for Diameter",
                   RFC 5777, February 2010.

14.2.  Informative References

   [MMUSIC-MEDIA]  Stucker, B. and H. Tschofenig, "Analysis of Middlebox
                   Interactions for Signaling Protocol Communication
                   along the Media Path", Work in Progress, March 2009.

   [NSIS-NTLP]     Schulzrinne, H. and M. Stiemerling, "GIST: General
                   Internet Signalling Transport", Work in Progress,
                   June 2009.

   [NSIS-QOS]      Manner, J., Karagiannis, G., and A. McDonald, "NSLP
                   for Quality-of-Service Signaling", Work in Progress,
                   January 2010.

   [RFC2205]       Braden, B., Zhang, L., Berson, S., Herzog, S., and S.
                   Jamin, "Resource ReSerVation Protocol (RSVP) --
                   Version 1 Functional Specification", RFC 2205,
                   September 1997.

   [RFC2211]       Wroclawski, J., "Specification of the Controlled-Load
                   Network Element Service", RFC 2211, September 1997.

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   [RFC2212]       Shenker, S., Partridge, C., and R. Guerin,
                   "Specification of Guaranteed Quality of Service",
                   RFC 2212, September 1997.

   [RFC2474]       Nichols, K., Blake, S., Baker, F., and D. Black,
                   "Definition of the Differentiated Services Field (DS
                   Field) in the IPv4 and IPv6 Headers", RFC 2474,
                   December 1998.

   [RFC2753]       Yavatkar, R., Pendarakis, D., and R. Guerin, "A
                   Framework for Policy-based Admission Control",
                   RFC 2753, January 2000.

   [RFC2865]       Rigney, C., Willens, S., Rubens, A., and W. Simpson,
                   "Remote Authentication Dial In User Service
                   (RADIUS)", RFC 2865, June 2000.

   [RFC3261]       Rosenberg, J., Schulzrinne, H., Camarillo, G.,
                   Johnston, A., Peterson, J., Sparks, R., Handley, M.,
                   and E. Schooler, "SIP: Session Initiation Protocol",
                   RFC 3261, June 2002.

   [RFC3313]       Marshall, W., "Private Session Initiation Protocol
                   (SIP) Extensions for Media Authorization", RFC 3313,
                   January 2003.

   [RFC3520]       Hamer, L-N., Gage, B., Kosinski, B., and H. Shieh,
                   "Session Authorization Policy Element", RFC 3520,
                   April 2003.

   [RFC3521]       Hamer, L-N., Gage, B., and H. Shieh, "Framework for
                   Session Set-up with Media Authorization", RFC 3521,
                   April 2003.

   [RFC4282]       Aboba, B., Beadles, M., Arkko, J., and P. Eronen,
                   "The Network Access Identifier", RFC 4282,
                   December 2005.

   [RFC4566]       Handley, M., Jacobson, V., and C. Perkins, "SDP:
                   Session Description Protocol", RFC 4566, July 2006.

   [RFC5246]       Dierks, T. and E. Rescorla, "The Transport Layer
                   Security (TLS) Protocol Version 1.2", RFC 5246,
                   August 2008.

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Authors' Addresses

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

   Phone: +1 908 582 2617
   EMail: d.sun@alcatel-lucent.com


   Peter J. McCann
   Motorola Labs
   1301 E. Algonquin Rd
   Schaumburg, IL  60196
   USA

   Phone: +1 847 576 3440
   EMail: pete.mccann@motorola.com


   Hannes Tschofenig
   Nokia Siemens Networks
   Linnoitustie 6
   Espoo  02600
   Finland

   Phone: +358 (50) 4871445
   EMail: Hannes.Tschofenig@gmx.net
   URI:   http://www.tschofenig.priv.at


   Tina Tsou
   Huawei
   Shenzhen,
   P.R.C

   EMail: tena@huawei.com


   Avri Doria
   Lulea University of Technology
   Arbetsvetenskap
   Lulea,   SE-97187
   Sweden

   EMail: avri@ltu.se

Top      Up      ToC       Page 51 
   Glen Zorn (editor)
   Network Zen
   1310 East Thomas Street
   #306
   Seattle, Washington  98102
   USA

   Phone: +1 (206) 377-9035
   EMail: gwz@net-zen.net