<pre>Internet Engineering Task Force (IETF)                       G. Ash, Ed.
Request for Comments: 5975                                          AT&amp;T
Category: Experimental                                     A. Bader, Ed.
ISSN: 2070-1721                                                 Ericsson
                                                         C. Kappler, Ed.
                                                  ck technology concepts
                                                            D. Oran, Ed.
                                                     Cisco Systems, Inc.
                                                            October 2010


                             <span class="h1">QSPEC Template</span>
    <span class="h1">for the Quality-of-Service NSIS Signaling Layer Protocol (NSLP)</span>

Abstract

   The Quality-of-Service (QoS) NSIS signaling layer protocol (NSLP) is
   used to signal QoS reservations and is independent of a specific QoS
   model (QOSM) such as IntServ or Diffserv.  Rather, all information
   specific to a QOSM is encapsulated in a separate object, the QSPEC.
   This document defines a template for the QSPEC including a number of
   QSPEC parameters.  The QSPEC parameters provide a common language to
   be reused in several QOSMs and thereby aim to ensure the
   extensibility and interoperability of QoS NSLP.  While the base
   protocol is QOSM-agnostic, the parameters that can be carried in the
   QSPEC object are possibly closely coupled to specific models.  The
   node initiating the NSIS signaling adds an Initiator QSPEC, which
   indicates the QSPEC parameters that must be interpreted by the
   downstream nodes less the reservation fails, thereby ensuring the
   intention of the NSIS initiator is preserved along the signaling
   path.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for examination, experimental implementation, and
   evaluation.

   This document defines an Experimental Protocol for the Internet
   community.  This document is a product of the Internet Engineering
   Task Force (IETF).  It represents the consensus of the IETF
   community.  It has received public review and has been approved for
   publication by the Internet Engineering Steering Group (IESG).  Not
   all documents approved by the IESG are a candidate for any level of
   Internet Standard; see <a href="./rfc5741#section-2">Section&nbsp;2 of RFC 5741</a>.






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   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   <a href="http://www.rfc-editor.org/info/rfc5975">http://www.rfc-editor.org/info/rfc5975</a>.

Copyright Notice

   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to <a href="https://www.rfc-editor.org/bcp/bcp78">BCP 78</a> and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (<a href="http://trustee.ietf.org/license-info">http://trustee.ietf.org/license-info</a>) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

































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Table of Contents

   <a href="#section-1">1</a>. Introduction ....................................................<a href="#page-4">4</a>
      <a href="#section-1.1">1.1</a>. Conventions Used in This Document ..........................<a href="#page-6">6</a>
   <a href="#section-2">2</a>. Terminology .....................................................<a href="#page-6">6</a>
   <a href="#section-3">3</a>. QSPEC Framework .................................................<a href="#page-7">7</a>
      <a href="#section-3.1">3.1</a>. QoS Models .................................................<a href="#page-7">7</a>
      <a href="#section-3.2">3.2</a>. QSPEC Objects ..............................................<a href="#page-9">9</a>
      <a href="#section-3.3">3.3</a>. QSPEC Parameters ..........................................<a href="#page-11">11</a>
           <a href="#section-3.3.1">3.3.1</a>. Traffic Model Parameter ............................<a href="#page-12">12</a>
           <a href="#section-3.3.2">3.3.2</a>. Constraints Parameters .............................<a href="#page-14">14</a>
           <a href="#section-3.3.3">3.3.3</a>. Traffic-Handling Directives ........................<a href="#page-16">16</a>
           <a href="#section-3.3.4">3.3.4</a>. Traffic Classifiers ................................<a href="#page-17">17</a>
      <a href="#section-3.4">3.4</a>. Example of QSPEC Processing ...............................<a href="#page-17">17</a>
   <a href="#section-4">4</a>. QSPEC Processing and Procedures ................................<a href="#page-20">20</a>
      <a href="#section-4.1">4.1</a>. Local QSPEC Definition and Processing .....................<a href="#page-20">20</a>
      4.2. Reservation Success/Failure, QSPEC Error Codes,
           and INFO-SPEC Notification ................................<a href="#page-23">23</a>
           <a href="#section-4.2.1">4.2.1</a>. Reservation Failure and Error E Flag ...............<a href="#page-24">24</a>
           <a href="#section-4.2.2">4.2.2</a>. QSPEC Parameter Not Supported N Flag ...............<a href="#page-25">25</a>
           <a href="#section-4.2.3">4.2.3</a>. INFO-SPEC Coding of Reservation Outcome ............<a href="#page-25">25</a>
           <a href="#section-4.2.4">4.2.4</a>. QNE Generation of a RESPONSE Message ...............<a href="#page-26">26</a>
           <a href="#section-4.2.5">4.2.5</a>. Special Case of Local QSPEC ........................<a href="#page-27">27</a>
      <a href="#section-4.3">4.3</a>. QSPEC Procedures ..........................................<a href="#page-27">27</a>
           <a href="#section-4.3.1">4.3.1</a>. Two-Way Transactions ...............................<a href="#page-28">28</a>
           <a href="#section-4.3.2">4.3.2</a>. Three-Way Transactions .............................<a href="#page-30">30</a>
           <a href="#section-4.3.3">4.3.3</a>. Resource Queries ...................................<a href="#page-32">32</a>
           <a href="#section-4.3.4">4.3.4</a>. Bidirectional Reservations .........................<a href="#page-33">33</a>
           <a href="#section-4.3.5">4.3.5</a>. Preemption .........................................<a href="#page-33">33</a>
      <a href="#section-4.4">4.4</a>. QSPEC Extensibility .......................................<a href="#page-33">33</a>
   <a href="#section-5">5</a>. QSPEC Functional Specification .................................<a href="#page-33">33</a>
      <a href="#section-5.1">5.1</a>. General QSPEC Formats .....................................<a href="#page-33">33</a>
           <a href="#section-5.1.1">5.1.1</a>. Common Header Format ...............................<a href="#page-34">34</a>
           <a href="#section-5.1.2">5.1.2</a>. QSPEC Object Header Format .........................<a href="#page-36">36</a>
      <a href="#section-5.2">5.2</a>. QSPEC Parameter Coding ....................................<a href="#page-37">37</a>
           <a href="#section-5.2.1">5.2.1</a>. &lt;TMOD-1&gt; Parameter .................................<a href="#page-37">37</a>
           <a href="#section-5.2.2">5.2.2</a>. &lt;TMOD-2&gt; Parameter .................................<a href="#page-38">38</a>
           <a href="#section-5.2.3">5.2.3</a>. &lt;Path Latency&gt; Parameter ...........................<a href="#page-39">39</a>
           <a href="#section-5.2.4">5.2.4</a>. &lt;Path Jitter&gt; Parameter ............................<a href="#page-40">40</a>
           <a href="#section-5.2.5">5.2.5</a>. &lt;Path PLR&gt; Parameter ...............................<a href="#page-41">41</a>
           <a href="#section-5.2.6">5.2.6</a>. &lt;Path PER&gt; Parameter ...............................<a href="#page-42">42</a>
           <a href="#section-5.2.7">5.2.7</a>. &lt;Slack Term&gt; Parameter .............................<a href="#page-43">43</a>
           5.2.8. &lt;Preemption Priority&gt; and &lt;Defending Priority&gt;
                  Parameters .........................................<a href="#page-43">43</a>
           <a href="#section-5.2.9">5.2.9</a>. &lt;Admission Priority&gt; Parameter .....................<a href="#page-44">44</a>
           <a href="#section-5.2.10">5.2.10</a>. &lt;RPH Priority&gt; Parameter ..........................<a href="#page-45">45</a>
           <a href="#section-5.2.11">5.2.11</a>. &lt;Excess Treatment&gt; Parameter ......................<a href="#page-46">46</a>
           <a href="#section-5.2.12">5.2.12</a>. &lt;PHB Class&gt; Parameter .............................<a href="#page-48">48</a>



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           <a href="#section-5.2.13">5.2.13</a>. &lt;DSTE Class Type&gt; Parameter .......................<a href="#page-49">49</a>
           <a href="#section-5.2.14">5.2.14</a>. &lt;Y.1541 QoS Class&gt; Parameter ......................<a href="#page-50">50</a>
   <a href="#section-6">6</a>. Security Considerations ........................................<a href="#page-51">51</a>
   <a href="#section-7">7</a>. IANA Considerations ............................................<a href="#page-51">51</a>
   <a href="#section-8">8</a>. Acknowledgements ...............................................<a href="#page-55">55</a>
   <a href="#section-9">9</a>. Contributors ...................................................<a href="#page-55">55</a>
   <a href="#section-10">10</a>. Normative References ..........................................<a href="#page-57">57</a>
   <a href="#section-11">11</a>. Informative References ........................................<a href="#page-59">59</a>
   <a href="#appendix-A">Appendix A</a>. Mapping of QoS Desired, QoS Available, and QoS
      Reserved of NSIS onto AdSpec, TSpec, and RSpec of RSVP IntServ .62
   <a href="#appendix-B">Appendix B</a>. Example of TMOD Parameter Encoding ....................<a href="#page-62">62</a>

<span class="h2"><a class="selflink" id="section-1" href="#section-1">1</a>.  Introduction</span>

   The QoS NSIS signaling layer protocol (NSLP) [<a href="./rfc5974" title="&quot;NSIS Signaling Layer Protocol (NSLP) for Quality-of- Service Signaling&quot;">RFC5974</a>] is used to
   signal QoS reservations for a data flow, provide forwarding resources
   (QoS) for that flow, and establish and maintain state at nodes along
   the path of the flow.  The design of QoS NSLP is conceptually similar
   to the decoupling between RSVP [<a href="./rfc2205" title="&quot;Resource ReSerVation Protocol (RSVP) -- Version 1 Functional Specification&quot;">RFC2205</a>] and the IntServ architecture
   [<a href="./rfc2210" title="&quot;The Use of RSVP with IETF Integrated Services&quot;">RFC2210</a>], where a distinction is made between the operation of the
   signaling protocol and the information required for the operation of
   the Resource Management Function (RMF).  [<a href="./rfc5974" title="&quot;NSIS Signaling Layer Protocol (NSLP) for Quality-of- Service Signaling&quot;">RFC5974</a>] describes the
   signaling protocol, while this document describes the RMF-related
   information carried in the QSPEC (QoS Specification) object carried
   in QoS NSLP messages.

   [<a id="ref-RFC5974">RFC5974</a>] defines four QoS NSLP messages -- RESERVE, QUERY, RESPONSE,
   and NOTIFY -- each of which may carry the QSPEC object, while this
   document describes a template for the QSPEC object.  The QSPEC object
   carries information on traffic descriptions, resources required,
   resources available, and other information required by the RMF.
   Therefore, the QSPEC template described in this document is closely
   tied to QoS NSLP, and the reader should be familiar with [<a href="./rfc5974" title="&quot;NSIS Signaling Layer Protocol (NSLP) for Quality-of- Service Signaling&quot;">RFC5974</a>] to
   fully understand this document.

   A QoS-enabled domain supports a particular QoS model (QOSM), which is
   a method to achieve QoS for a traffic flow.  A QOSM incorporates QoS
   provisioning methods and a QoS architecture, and defines the behavior
   of the RMF that reserves resources for each flow, including inputs
   and outputs.  The QoS NSLP protocol is able to signal QoS
   reservations for different QOSMs, wherein all information specific to
   a QOSM is encapsulated in the QSPEC object, and only the RMF specific
   to a given QOSM will need to interpret the QSPEC.  Examples of QOSMs
   are IntServ, Diffserv admission control, and those specified in
   [<a href="#ref-CL-QOSM" title="&quot;A QoS Model for Signaling IntServ Controlled-Load Service with NSIS&quot;">CL-QOSM</a>], [<a href="./rfc5976" title="&quot;Y.1541-QOSM: Model for Networks Using Y.1541 Quality-of-Service Classes&quot;">RFC5976</a>], and [<a href="./rfc5977" title="&quot;RMD-QOSM: The NSIS Quality-of-Service Model for Resource Management in Diffserv&quot;">RFC5977</a>].






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   QSPEC parameters include, for example:

      o  a mandatory traffic model (TMOD) parameter,
      o  constraints parameters such as path latency and path jitter,
      o  traffic handling directives such as excess treatment, and
      o  traffic classifiers such as PHB class.

   While the base protocol is QOSM-agnostic, the parameters that can be
   carried in the QSPEC object are possibly closely coupled to specific
   models.

   QSPEC objects loosely correspond to the TSpec, RSpec, and AdSpec
   objects specified in RSVP and may contain, respectively, a
   description of QoS Desired, QoS Reserved, and QoS Available.  Going
   beyond RSVP functionality, the QSPEC also allows indicating a range
   of acceptable QoS by defining a QSPEC object denoting minimum QoS.
   Usage of these QSPEC objects is not bound to particular message
   types, thus allowing for flexibility.  A QSPEC object collecting
   information about available resources may travel in any QoS NSLP
   message, for example, a QUERY message or a RESERVE message, as
   defined in [<a href="./rfc5974" title="&quot;NSIS Signaling Layer Protocol (NSLP) for Quality-of- Service Signaling&quot;">RFC5974</a>].  The QSPEC travels in QoS NSLP messages but is
   opaque to the QoS NSLP and is only interpreted by the RMF.

   Interoperability between QoS NSIS entities (QNEs) in different
   domains is enhanced by the definition of a common set of QSPEC
   parameters.  A QoS NSIS initiator (QNI) initiating the QoS NSLP
   signaling adds an Initiator QSPEC object containing parameters
   describing the desired QoS, normally based on the QOSM it supports.
   QSPEC parameters flagged by the QNI must be interpreted by all QNEs
   in the path, else the reservation fails.  In contrast, QSPEC
   parameters not flagged by the QNI may be skipped if not understood.
   Additional QSPEC parameters can be defined by informational
   specification documents, and thereby ensure the extensibility and
   flexibility of QoS NSLP.

   A Local QSPEC can be defined in a local domain with the Initiator
   QSPEC encapsulated, where the Local QSPEC must be functionally
   consistent with the Initiator QSPEC in terms of defined source
   traffic and other constraints.  That is, a domain-specific local
   QSPEC can be defined and processed in a local domain, which could,
   for example, enable simpler processing by QNEs within the local
   domain.

   In <a href="#section-3.4">Section 3.4</a>, an example of QSPEC processing is provided.







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<span class="h3"><a class="selflink" id="section-1.1" href="#section-1.1">1.1</a>.  Conventions Used in This Document</span>

   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 <a href="./rfc2119">RFC 2119</a> [<a href="./rfc2119" title="&quot;Key words for use in RFCs to Indicate Requirement Levels&quot;">RFC2119</a>].

<span class="h2"><a class="selflink" id="section-2" href="#section-2">2</a>.  Terminology</span>

   Initiator QSPEC: The Initiator QSPEC is included in a QoS NSLP
   message by the QNI/QNR.  It travels end-to-end to the QNR/QNI and is
   never removed.

   Local QSPEC: A Local QSPEC is used in a local domain and is domain
   specific.  It encapsulates the Initiator QSPEC and is removed at the
   egress of the local domain.

   Minimum QoS: QSPEC object that, together with a description of QoS
   Desired or QoS Available, allows the QNI to specify a QoS range,
   i.e., an upper and lower bound.  If the QoS Desired cannot be
   reserved, QNEs are going to decrease the reservation until the
   minimum QoS is hit.  Note that the term "minimum" is used
   generically, since for some parameters, such as loss rate and
   latency, what is specified is the maximum acceptable value.

   QNE: QoS NSIS Entity, a node supporting QoS NSLP.

   QNI: QoS NSIS Initiator, a node initiating QoS NSLP signaling.

   QNR: QoS NSIS Receiver, a node terminating QoS NSLP signaling.

   QoS Available: QSPEC object containing parameters describing the
   available resources.  They are used to collect information along a
   reservation path.

   QoS Desired: QSPEC object containing parameters describing the
   desired QoS for which the sender requests reservation.

   QoS Model (QOSM): a method to achieve QoS for a traffic flow, e.g.,
   IntServ Controlled Load; specifies the subset of QSPEC QoS
   constraints and traffic handling directives that a QNE implementing
   that QOSM is capable of supporting and how resources will be managed
   by the RMF.

   QoS Reserved: QSPEC object containing parameters describing the
   reserved resources and related QoS parameters.

   QSPEC: the object of QoS NSLP that contains all QoS-specific
   information.



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   QSPEC parameter: Any parameter appearing in a QSPEC; for example,
   traffic model (TMOD), path latency, and excess treatment parameters.

   QSPEC Object: Main building blocks containing a QSPEC parameter set
   that is the input or output of an RMF operation.

   QSPEC Type: Identifies a particular QOSM used in the QSPEC

   Resource Management Function (RMF): Functions that are related to
   resource management and processing of QSPEC parameters.

<span class="h2"><a class="selflink" id="section-3" href="#section-3">3</a>. QSPEC Framework</span>

   The overall framework for the QoS NSLP is that [<a href="./rfc5974" title="&quot;NSIS Signaling Layer Protocol (NSLP) for Quality-of- Service Signaling&quot;">RFC5974</a>] defines QoS
   signaling and semantics, the QSPEC template defines the container and
   semantics for QoS parameters and objects, and informational
   specifications define QoS methods and procedures for using QoS
   signaling and QSPEC parameters/objects within specific QoS
   deployments.  QoS NSLP is a generic QoS signaling protocol that can
   signal for many QOSMs.

<span class="h3"><a class="selflink" id="section-3.1" href="#section-3.1">3.1</a>.  QoS Models</span>

   A QOSM is a method to achieve QoS for a traffic flow, e.g., IntServ
   Controlled Load [<a href="#ref-CL-QOSM" title="&quot;A QoS Model for Signaling IntServ Controlled-Load Service with NSIS&quot;">CL-QOSM</a>], Resource Management with Diffserv
   [<a href="./rfc5977" title="&quot;RMD-QOSM: The NSIS Quality-of-Service Model for Resource Management in Diffserv&quot;">RFC5977</a>], and QoS signaling for Y.1541 QoS classes [<a href="./rfc5976" title="&quot;Y.1541-QOSM: Model for Networks Using Y.1541 Quality-of-Service Classes&quot;">RFC5976</a>].  A
   QOSM specifies a set of QSPEC parameters that describe the QoS
   desired and how resources will be managed by the RMF.  The RMF
   implements functions that are related to resource management and
   processes the QSPEC parameters.

   QOSMs affect the operation of the RMF in NSIS-capable nodes and the
   information carried in QSPEC objects.  Under some circumstances
   (e.g., aggregation), they may cause a separate NSLP session to be
   instantiated by having the RMF as a QNI.  QOSM specifications may
   define RMF triggers that cause the QoS NSLP to run semantics within
   the underlying QoS NSLP signaling state and messaging processing
   rules, as defined in <a href="./rfc5974#section-5.2">Section&nbsp;5.2 of [RFC5974]</a>.  New QoS NSLP message
   processing rules can only be defined in extensions to QoS NSLP.  If a
   QOSM specification defines triggers that deviate from existing QoS
   NSLP processing rules, the fallback for QNEs not supporting that QOSM
   are the QoS NSLP state transition/message processing rules.

   The QOSM specification includes how the requested QoS resources will
   be described and how they will be managed by the RMF.  For this
   purpose, the QOSM specification defines a set of QSPEC parameters it
   uses to describe the desired QoS and resource control in the RMF, and
   it may define additional QSPEC parameters.



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   When a QoS NSLP message travels through different domains, it may
   encounter different QOSMs.  Since QOSMs use different QSPEC
   parameters for describing resources, the QSPEC parameters included by
   the QNI may not be understood in other domains.  The QNI therefore
   can flag those QSPEC parameters it considers vital with the M flag.
   QSPEC parameters with the M flag set must be interpreted by the
   downstream QNEs, or the reservation fails.  QSPEC parameters without
   the M flag set should be interpreted by the downstream QNEs, but may
   be ignored if not understood.

   A QOSM specification SHOULD include the following:

   - role of QNEs, e.g., location, frequency, statefulness, etc.
   - QSPEC definition including QSPEC parameters
   - QSPEC procedures applicable to this QOSM
   - QNE processing rules describing how QSPEC information is treated
     and interpreted in the RMF, e.g., admission control, scheduling,
     policy control, QoS parameter accumulation (e.g., delay)
   - at least one bit-level QSPEC example
   - QSPEC parameter behavior for new QSPEC parameters that the QOSM
     specification defines
   - a definition of what happens in case of preemption if the default
     QNI behavior (teardown preempted reservation) is not followed (see
     <a href="#section-4.3.5">Section 4.3.5</a>)

   A QOSM specification MAY include the following:

   - definitions of additional QOSM-specific error codes, as discussed
     in <a href="#section-4.2.3">Section 4.2.3</a>
   - the QoS-NSLP options a QOSM wants to use, when several options are
     available for a QOSM (e.g., Local QSPEC to either a) hide the
     Initiator QSPEC within a local domain message, or b) encapsulate
     the Initiator QSPEC).

   QOSMs are free, subject to IANA registration and review rules, to
   extend QSPECs by adding parameters of any of the kinds supported by
   the QSPEC.  This includes traffic description parameters, constraint
   parameters, and traffic handling directives.  QOSMs are not
   permitted, however, to reinterpret or redefine the QSPEC parameters
   specified in this document.  Note that signaling functionality is
   only defined by the QoS NSLP document [<a href="./rfc5974" title="&quot;NSIS Signaling Layer Protocol (NSLP) for Quality-of- Service Signaling&quot;">RFC5974</a>] and not by this
   document or by QOSM specification documents.









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<span class="h3"><a class="selflink" id="section-3.2" href="#section-3.2">3.2</a>.  QSPEC Objects</span>

   The QSPEC is the object of QoS NSLP containing QSPEC objects and
   parameters.  QSPEC objects are the main building blocks of the QSPEC
   parameter set that is input or output of an RMF operation.  QSPEC
   parameters are the parameters appearing in a QSPEC, which must
   include the traffic model parameter (TMOD), and may optionally
   include constraints (e.g., path latency), traffic handling directives
   (e.g., excess treatment), and traffic classifiers (e.g., PHB class).
   The RMF implements functions that are related to resource management
   and processes the QSPEC parameters.

   The QSPEC consists of a QSPEC version number and QSPEC objects.  IANA
   assigns a new QSPEC version number when the current version is
   deprecated or deleted (as required by a specification).  Note that a
   new QSPEC version number is not needed when new QSPEC parameters are
   specified.  Later QSPEC versions MUST be backward compatible with
   earlier QSPEC versions.  That is, a version n+1 device must support
   QSPEC version n (or earlier).  On the other hand, if a QSPEC version
   n (or earlier) device receives an NSLP message specifying QSPEC
   version n+1, then the version n device responds with an 'Incompatible
   QSPEC' error code (0x0f) response, as discussed in <a href="#section-4.2.3">Section 4.2.3</a>,
   allowing the QNE that sent the NSLP message to retry with a lower
   QSPEC version.

   This document provides a template for the QSPEC in order to promote
   interoperability between QOSMs.  Figure 1 illustrates how the QSPEC
   is composed of up to 4 QSPEC objects, namely QoS Desired, QoS
   Available, QoS Reserved, and Minimum QoS.  Each of these QSPEC
   objects consists of a number of QSPEC parameters.  A given QSPEC may
   contain only a subset of the QSPEC objects, e.g., QoS Desired.  The
   QSPEC objects QoS Desired, QoS Available, QoS Reserved and Minimum
   QoS MUST all be supported by QNEs and MAY appear in any QSPEC object
   carried in any QoS NSLP message (RESERVE, QUERY, RESPONSE, NOTIFY).
   See [<a href="./rfc5974" title="&quot;NSIS Signaling Layer Protocol (NSLP) for Quality-of- Service Signaling&quot;">RFC5974</a>] for descriptions of the QoS NSLP RESERVE, QUERY,
   RESPONSE, and NOTIFY messages.















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   +---------------------------------------+
   |            QSPEC Objects              |
   +---------------------------------------+

   \________________ ______________________/
                    V
   +----------+----------+---------+-------+
   |QoS Desir.|QoS Avail.|QoS Rsrv.|Min QoS|
   +----------+----------+---------+-------+

   \____ ____/\___ _____/\___ ____/\__ ___/
        V         V          V        V

   +-------------+...     +-------------+...
   |QSPEC Para. 1|        |QSPEC Para. n|
   +-------------+...     +-------------+...

       Figure 1: Structure of the QSPEC

   Use of the 4 QSPEC objects (QoS Desired, QoS Available, QoS Reserved,
   and Minimum QoS) is described in <a href="#section-4.3">Section 4.3</a> for 3 message sequences
   and 7 object combinations.

   The QoS Desired Object describe the resources the QNI desires to
   reserve, and hence this is a read-only QSPEC object in that the QSPEC
   parameters carried in the object may not be overwritten.  QoS Desired
   is always included in a RESERVE message and sometimes included in the
   QUERY message (see <a href="#section-4.3">Section 4.3</a> for details).

   As described in <a href="#section-4.3">Section 4.3</a>, the QoS Available object may travel in a
   RESERVE message, RESPONSE Message, or QUERY message and may collect
   information on the resources currently available on the path.  In
   this case, QoS Available is a read-write object, which means the
   QSPEC parameters contained in QoS Available may be updated, but they
   cannot be deleted.  As such, each QNE MUST inspect all parameters of
   this QSPEC object, and if resources available to this QNE are less
   than what a particular parameter says currently, the QNE MUST adapt
   this parameter accordingly.  Hence, when the message arrives at the
   recipient of the message, &lt;QoS Available&gt; reflects the bottleneck of
   the resources currently available on a path.  It can be used in a
   QUERY message, for example, to collect the available resources along
   a data path.

   When QoS Available travels in a RESPONSE message, it in fact just
   transports the result of a previous measurement performed by a
   RESERVE or QUERY message back to the initiator.  Therefore, in this





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   case, QoS Available is read-only.  In one other instance described in
   <a href="#section-4.3.2">Section 4.3.2</a> (Case 3), QoS Available is sent by the QNI in a RESERVE
   message as a read-only QSPEC object (see <a href="#section-4.3.2">Section 4.3.2</a> for details).

   The QoS Reserved object reflects the resources that are being
   reserved.  It is a read-only object and is always included in a
   RESPONSE message if QoS Desired is included in the RESERVE message
   (see <a href="#section-4.3">Section 4.3</a> for details).

   Minimum QoS does not have an equivalent in RSVP.  It allows the QNI
   to define a range of acceptable QoS levels by including both the
   desired QoS value and the minimum acceptable QoS in the same message.
   Note that the term "minimum" is used generically, since for some
   parameters, such as loss rate and latency, what is specified is the
   maximum acceptable value.  It is a read-only object, and may be
   included in a RESERVE message, RESPONSE message, or QUERY message
   (see <a href="#section-4.3">Section 4.3</a> for details).  The desired QoS is included with a
   QoS Desired and/or a QoS Available QSPEC object seeded to the desired
   QoS value.  The minimum acceptable QoS value MAY be coded in the
   Minimum QoS QSPEC object.  As the message travels towards the QNR,
   QoS Available is updated by QNEs on the path.  If its value drops
   below the value of Minimum QoS, the reservation fails and is aborted.
   When this method is employed, the QNR signals back to the QNI the
   value of QoS Available attained in the end, because the reservation
   may need to be adapted accordingly (see <a href="#section-4.3">Section 4.3</a> for details).

   Note that the relationship of QSPEC objects to RSVP objects is
   covered in <a href="#appendix-A">Appendix A</a>.

<span class="h3"><a class="selflink" id="section-3.3" href="#section-3.3">3.3</a>.  QSPEC Parameters</span>

   QSPEC parameters provide a common language for building QSPEC
   objects.  This document defines a number of QSPEC parameters;
   additional parameters may be defined in separate QOSM specification
   documents.  For example, QSPEC parameters are defined in [<a href="./rfc5976" title="&quot;Y.1541-QOSM: Model for Networks Using Y.1541 Quality-of-Service Classes&quot;">RFC5976</a>]
   and [<a href="./rfc5977" title="&quot;RMD-QOSM: The NSIS Quality-of-Service Model for Resource Management in Diffserv&quot;">RFC5977</a>].

   One QSPEC parameter, &lt;TMOD&gt;, is special.  It provides a description
   of the traffic for which resources are reserved.  This parameter must
   be included by the QNI, and it must be interpreted by all QNEs.  All
   other QSPEC parameters are populated by a QNI if they are applicable
   to the underlying QoS desired.  For these QSPEC parameters, the QNI
   sets the M flag if they must be interpreted by downstream QNEs.  If
   QNEs cannot interpret the parameter, the reservation fails.  QSPEC
   parameters populated by a QNI without the M flag set should be
   interpreted by downstream QNEs, but may be ignored if not understood.





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   In this document, the term 'interpret' means, in relation to RMF
   processing of QSPEC parameters, that the RMF processes the QSPEC
   parameter according to the commonly accepted normative procedures
   specified by references given for each QSPEC parameter.  Note that a
   QNE need only interpret a QSPEC parameter if it is populated in the
   QSPEC object by the QNI; if not populated in the QSPEC, the QNE does
   not interpret it of course.

   Note that when an ingress QNE in a local domain defines a Local QSPEC
   and encapsulates the Initiator QSPEC, the QNEs in the interior local
   domain need only process the Local QSPEC and can ignore the Initiator
   (encapsulated) QSPEC.  However, edge QNEs in the local domain indeed
   must interpret the QSPEC parameters populated in the Initiator QSPEC
   with the M flag set and should interpret QSPEC parameters populated
   in the Initiator QSPEC without the M flag set.

   As described in the previous section, QoS parameters may be
   overwritten depending on which QSPEC object and which message they
   appear in.

<span class="h4"><a class="selflink" id="section-3.3.1" href="#section-3.3.1">3.3.1</a>.  Traffic Model Parameter</span>

   The &lt;Traffic Model&gt; (TMOD) parameter is mandatory for the QNI to
   include in the Initiator QSPEC and mandatory for downstream QNEs to
   interpret.  The traffic description specified by the TMOD parameter
   is a container consisting of 5 sub-parameters [<a href="./rfc2212" title="&quot;Specification of Guaranteed Quality of Service&quot;">RFC2212</a>]:

   o  rate (r) specified in octets per second
   o  bucket size (b) specified in octets
   o  peak rate (p) specified in octets per second
   o  minimum policed unit (m) specified in octets
   o  maximum packet size (MPS) specified in octets

   The TMOD parameter takes the form of a token bucket of rate (r) and
   bucket size (b), plus a peak rate (p), minimum policed unit (m), and
   maximum packet size (MPS).

   Both b and r MUST be positive.  The rate, r, is measured in octets of
   IP packets per second, and can range from 1 octet per second to as
   large as 40 teraoctets per second.  The bucket depth, b, is also
   measured in octets and can range from 1 octet to 250 gigaoctets.  The
   peak rate, p, is measured in octets of IP packets per second and has
   the same range and suggested representation as the bucket rate.

   The peak rate is the maximum rate at which the source and any
   reshaping (defined below) may inject bursts of traffic into the
   network.  More precisely, it is a requirement that for all time
   periods the amount of data sent cannot exceed MPS+pT, where MPS is



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   the maximum packet size and T is the length of the time period.
   Furthermore, p MUST be greater than or equal to the token bucket
   rate, r.  If the peak rate is unknown or unspecified, then p MUST be
   set to infinity.

   The minimum policed unit, m, is an integer measured in octets.  All
   IP packets less than size m will be counted, when policed and tested
   for conformance to the TMOD, as being of size m.

   The maximum packet size, MPS, is the biggest packet that will conform
   to the traffic specification; it is also measured in octets.  The
   flow MUST be rejected if the requested maximum packet size is larger
   than the MTU of the link.  Both m and MPS MUST be positive, and m
   MUST be less than or equal to MPS.

   Policing compares arriving traffic against the TMOD parameters at the
   edge of the network.  Traffic is policed to ensure it conforms to the
   token bucket.  Reshaping attempts to restore the (possibly distorted)
   traffic's shape to conform to the TMOD parameters, and traffic that
   is in violation of the TMOD is discovered because the reshaping fails
   and the reshaping buffer overflows.

   The token bucket and peak rate parameters require that traffic MUST
   obey the rule that over all time periods, the amount of data sent
   cannot exceed MPS+min[pT, rT+b-MPS], where r and b are the token
   bucket parameters, MPS is the maximum packet size, and T is the
   length of the time period (note that when p is infinite, this reduces
   to the standard token bucket requirement).  For the purposes of this
   accounting, links MUST count packets that are smaller than the
   minimum policing unit as being of size m.  Packets that arrive at an
   element and cause a violation of the MPS + min[pT, rT+b-MPS] bound
   are considered non-conformant.

   All 5 of the sub-parameters MUST be included in the TMOD parameter.
   The TMOD parameter can be set to describe the traffic source.  If,
   for example, TMOD is set to specify bandwidth only, then set r = peak
   rate = p, b = large, and m = large.  As another example, if TMOD is
   set for TCP traffic, then set r = average rate, b = large, and p =
   large.

   When the 5 TMOD sub-parameters are included in QoS Available, they
   provide information, for example, about the TMOD resources available
   along the path followed by a data flow.  The value of TMOD at a QNE
   is an estimate of the TMOD resources the QNE has available for
   packets following the path up to the next QNE, including its outgoing
   link, if this link exists.  Furthermore, the QNI MUST account for the
   resources of the ingress link, if this link exists.  Computation of




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   the value of this parameter SHOULD take into account all information
   available to the QNE about the path, taking into consideration
   administrative and policy controls, as well as physical resources.

   The output composed value is the minimum of the QNE's value and the
   input composed value for r, b, p, and MPS, and the maximum of the
   QNE's value and the input composed value for m.  This quantity, when
   composed end-to-end, informs the QNR (or QNI in a RESPONSE message)
   of the minimal TMOD resources along the path from QNI to QNR.

   Two TMOD parameters are defined in <a href="#section-5">Section 5</a>, &lt;TMOD-1&gt; and &lt;TMOD-2&gt;,
   where the second parameter (&lt;TMOD-2&gt;) is specified as could be needed
   to support some Diffserv applications.  For example, it is typically
   assumed that Diffserv Expedited Forwarding (EF) traffic is shaped at
   the ingress by a single rate token bucket.  Therefore, a single TMOD
   parameter is sufficient to signal Diffserv EF traffic.  However, for
   Diffserv Assured Forwarding (AF) traffic, two sets of token bucket
   parameters are needed -- one for the average traffic and one for the
   burst traffic.  [<a href="./rfc2697" title="&quot;A Single Rate Three Color Marker&quot;">RFC2697</a>] defines a Single Rate Three Color Marker
   (srTCM), which meters a traffic stream and marks its packets
   according to three traffic parameters, Committed Information Rate
   (CIR), Committed Burst Size (CBS), and Excess Burst Size (EBS), to be
   either green, yellow, or red.  A packet is marked green if it does
   not exceed the CBS; yellow if it does exceed the CBS, but not the
   EBS; and red otherwise.  [<a href="./rfc2697" title="&quot;A Single Rate Three Color Marker&quot;">RFC2697</a>] defines specific procedures using
   two token buckets that run at the same rate.  Therefore, 2 TMOD
   parameters are sufficient to distinguish among 3 levels of drop
   precedence.  An example is also described in the Appendix to
   [<a href="./rfc2597" title="&quot;Assured Forwarding PHB Group&quot;">RFC2597</a>].

<span class="h4"><a class="selflink" id="section-3.3.2" href="#section-3.3.2">3.3.2</a>.  Constraints Parameters</span>

   &lt;Path Latency&gt;, &lt;Path Jitter&gt;, &lt;Path PLR&gt;, and &lt;Path PER&gt; are QSPEC
   parameters describing the desired path latency, path jitter, packet
   loss ratio, and path packet error ratio, respectively.  Since these
   parameters are cumulative, an individual QNE cannot decide whether
   the desired path latency, etc., is available, and hence they cannot
   decide whether a reservation fails.  Rather, when these parameters
   are included in &lt;Desired QoS&gt;, the QNI SHOULD also include
   corresponding parameters in a QoS Available QSPEC object in order to
   facilitate collecting this information.

   The &lt;Path Latency&gt; parameter accumulates the latency of the packet
   forwarding process associated with each QNE, where the latency is
   defined to be the mean packet delay, measured in microseconds, added
   by each QNE.  This delay results from the combination of link
   propagation delay, packet processing, and queuing.  Each QNE MUST add
   the propagation delay of its outgoing link, if this link exists.



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   Furthermore, the QNI SHOULD add the propagation delay of the ingress
   link, if this link exists.  The composition rule for the &lt;Path
   Latency&gt; parameter is summation with a clamp of (2^32) - 1 on the
   maximum value.  This quantity, when composed end-to-end, informs the
   QNR (or QNI in a RESPONSE message) of the minimal packet delay along
   the path from QNI to QNR.  The purpose of this parameter is to
   provide a minimum path latency for use with services that provide
   estimates or bounds on additional path delay [<a href="./rfc2212" title="&quot;Specification of Guaranteed Quality of Service&quot;">RFC2212</a>].

   The &lt;Path Jitter&gt; parameter accumulates the jitter of the packet
   forwarding process associated with each QNE, where the jitter is
   defined to be the nominal jitter, measured in microseconds, added by
   each QNE.  IP packet jitter, or delay variation, is defined in
   <a href="./rfc3393#section-3.4">[RFC3393], Section&nbsp;3.4</a> (Type-P-One-way-ipdv), and where the [<a href="./rfc3393" title="&quot;IP Packet Delay Variation Metric for IP Performance Metrics (IPPM)&quot;">RFC3393</a>]
   selection function includes the packet with minimum delay such that
   the distribution is equivalent to 2-point delay variation in
   [<a href="#ref-Y.1540" title="&quot;Internet Protocol Data Communication Service - IP Packet Transfer and Availability Performance Parameters&quot;">Y.1540</a>].  The suggested evaluation interval is 1 minute.  This
   jitter results from packet-processing limitations, and includes any
   variable queuing delay that may be present.  Each QNE MUST add the
   jitter of its outgoing link, if this link exists.  Furthermore, the
   QNI SHOULD add the jitter of the ingress link, if this link exists.
   The composition method for the &lt;Path Jitter&gt; parameter is the
   combination of several statistics describing the delay variation
   distribution with a clamp on the maximum value (note that the methods
   of accumulation and estimation of nominal QNE jitter are specified in
   clause 8 of [<a href="#ref-Y.1541" title="&quot;Network Performance Objectives for IP-Based Services&quot;">Y.1541</a>]).  This quantity, when composed end-to-end,
   informs the QNR (or QNI in a RESPONSE message) of the nominal packet
   jitter along the path from QNI to QNR.  The purpose of this parameter
   is to provide a nominal path jitter for use with services that
   provide estimates or bounds on additional path delay [<a href="./rfc2212" title="&quot;Specification of Guaranteed Quality of Service&quot;">RFC2212</a>].

   The &lt;Path PLR&gt; parameter is the unit-less ratio of total lost IP
   packets to total transmitted IP packets.  &lt;Path PLR&gt; accumulates the
   packet loss ratio (PLR) of the packet-forwarding process associated
   with each QNE, where the PLR is defined to be the PLR added by each
   QNE.  Each QNE MUST add the PLR of its outgoing link, if this link
   exists.  Furthermore, the QNI MUST add the PLR of the ingress link,
   if this link exists.  The composition rule for the &lt;Path PLR&gt;
   parameter is summation with a clamp on the maximum value. (This
   assumes sufficiently low PLR values such that summation error is not
   significant; however, a more accurate composition function is
   specified in clause 8 of [<a href="#ref-Y.1541" title="&quot;Network Performance Objectives for IP-Based Services&quot;">Y.1541</a>].)  This quantity, when composed
   end-to-end, informs the QNR (or QNI in a RESPONSE message) of the
   minimal packet PLR along the path from QNI to QNR.

   Packet error ratio [<a href="#ref-Y.1540" title="&quot;Internet Protocol Data Communication Service - IP Packet Transfer and Availability Performance Parameters&quot;">Y.1540</a>, <a href="#ref-Y.1541" title="&quot;Network Performance Objectives for IP-Based Services&quot;">Y.1541</a>] is the unit-less ratio of total
   errored IP packet outcomes to the total of successful IP packet
   transfer outcomes plus errored IP packet outcomes in a population of



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   interest, with a resolution of at least 10^-9.  If lesser resolution
   is available in a value, the unused digits MUST be set to zero.  Note
   that the number of errored packets observed is directly related to
   the confidence in the result.  The &lt;Path PER&gt; parameter accumulates
   the packet error ratio (PER) of the packet forwarding process
   associated with each QNE, where the PER is defined to be the PER
   added by each QNE.  Each QNE MUST add the PER of its outgoing link,
   if this link exists.  Furthermore, the QNI SHOULD add the PER of the
   ingress link, if this link exists.  The composition rule for the
   &lt;Path PER&gt; parameter is summation with a clamp on the maximum value.
   (This assumes sufficiently low PER values such that summation error
   is not significant; however, a more accurate composition function is
   specified in clause 8 of [<a href="#ref-Y.1541" title="&quot;Network Performance Objectives for IP-Based Services&quot;">Y.1541</a>].)  This quantity, when composed
   end-to-end, informs the QNR (or QNI in a RESPONSE message) of the
   minimal packet PER along the path from QNI to QNR.

   The slack term parameter is the difference between desired delay and
   delay obtained by using bandwidth reservation, and it is used to
   reduce the resource reservation for a flow [<a href="./rfc2212" title="&quot;Specification of Guaranteed Quality of Service&quot;">RFC2212</a>].

<span class="h4"><a class="selflink" id="section-3.3.3" href="#section-3.3.3">3.3.3</a>.  Traffic-Handling Directives</span>

   An application MAY like to reserve resources for packets and also
   specify a specific traffic-handling behavior, such as &lt;Excess
   Treatment&gt;.  In addition, as discussed in <a href="#section-3.1">Section 3.1</a>, an application
   MAY like to define RMF triggers that cause the QoS NSLP to run
   semantics within the underlying QoS NSLP signaling state / messaging
   processing rules, as defined in <a href="./rfc5974#section-5.2">Section&nbsp;5.2 of [RFC5974]</a>.  Note,
   however, that new QoS NSLP message processing rules can only be
   defined in extensions to the QoS NSLP.  As with constraints
   parameters and other QSPEC parameters, Traffic Handling Directives
   parameters may be defined in QOSM specifications in order to provide
   support for QOSM-specific resource management functions.  Such QOSM-
   specific parameters are already defined, for example, in [<a href="./rfc5976" title="&quot;Y.1541-QOSM: Model for Networks Using Y.1541 Quality-of-Service Classes&quot;">RFC5976</a>],
   [<a href="./rfc5977" title="&quot;RMD-QOSM: The NSIS Quality-of-Service Model for Resource Management in Diffserv&quot;">RFC5977</a>], and [<a href="#ref-CL-QOSM" title="&quot;A QoS Model for Signaling IntServ Controlled-Load Service with NSIS&quot;">CL-QOSM</a>].  Generally, a Traffic Handling Directives
   parameters is expected to be set by the QNI in &lt;QoS Desired&gt;, and to
   not be included in &lt;QoS Available&gt;.  If such a parameter is included
   in &lt;QoS Available&gt;, QNEs may change their value.

   The &lt;Preemption Priority&gt; parameter is the priority of the new flow
   compared with the &lt;Defending Priority&gt; of previously admitted flows.
   Once a flow is admitted, the preemption priority becomes irrelevant.
   The &lt;Defending Priority&gt; parameter is used to compare with the
   preemption priority of new flows.  For any specific flow, its
   preemption priority MUST always be less than or equal to the
   defending priority.  &lt;Admission Priority&gt; and &lt;RPH Priority&gt; provide
   an essential way to differentiate flows for emergency services,
   Emergency Telecommunications Service (ETS), E911, etc., and assign



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   them a higher admission priority than normal priority flows and best-
   effort priority flows.

   The &lt;Excess Treatment&gt; parameter describes how the QNE will process
   out-of-profile traffic.  Excess traffic MAY be dropped, shaped,
   and/or re-marked.

<span class="h4"><a class="selflink" id="section-3.3.4" href="#section-3.3.4">3.3.4</a>.  Traffic Classifiers</span>

   An application MAY like to reserve resources for packets with a
   particular Diffserv per-hop behavior (PHB) [<a href="./rfc2475" title="&quot;An Architecture for Differentiated Service&quot;">RFC2475</a>].  Note that PHB
   class is normally set by a downstream QNE to tell the QNI how to mark
   traffic to ensure the treatment that is designated by admission
   control; however, setting of the parameter by the QNI is not
   precluded.  An application MAY like to reserve resources for packets
   with a particular QoS class, e.g., Y.1541 QoS class [<a href="#ref-Y.1541" title="&quot;Network Performance Objectives for IP-Based Services&quot;">Y.1541</a>] or
   Diffserv-aware MPLS traffic engineering (DSTE) class type [RFC3564,
   <a href="./rfc4124">RFC4124</a>].  These parameters are useful in various QOSMs, e.g.,
   [<a href="./rfc5976" title="&quot;Y.1541-QOSM: Model for Networks Using Y.1541 Quality-of-Service Classes&quot;">RFC5976</a>], [<a href="./rfc5977" title="&quot;RMD-QOSM: The NSIS Quality-of-Service Model for Resource Management in Diffserv&quot;">RFC5977</a>], and other QOSMs yet to be defined (e.g., DSTE-
   QOSM).  This is intended to provide guidelines to QOSMs on how to
   encode these parameters; use of the PHB class parameter is
   illustrated in the example in the following section.

<span class="h3"><a class="selflink" id="section-3.4" href="#section-3.4">3.4</a>.  Example of QSPEC Processing</span>

   This section illustrates the operation and use of the QSPEC within
   the NSLP.  The example configuration in shown in Figure 2.

   +----------+      /-------\       /--------\       /--------\
   | Laptop   |     |   Home  |     |  Cable   |     | Diffserv |
   | Computer |-----| Network |-----| Network  |-----| Network  |----+
   +----------+     | No QOSM |     |DQOS QOSM |     | RMD QOSM |    |
                     \-------/       \--------/       \--------/     |
                                                                     |
                     +-----------------------------------------------+
                     |
                     |    /--------\      +----------+
                     |   |    XG    |     | Handheld |
                     +---| Wireless |-----|  Device  |
                         | XG QOSM  |     +----------+
                          \--------/

      Figure 2: Example Configuration of QoS-NSLP/QSPEC Operation

   In this configuration, a laptop computer and a handheld wireless
   device are the endpoints for some application that has QoS
   requirements.  Assume initially that the two endpoints are stationary
   during the application session, later we consider mobile endpoints.



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   For this session, the laptop computer is connected to a home network
   that has no QoS support.  The home network is connected to a
   CableLabs-type cable access network with dynamic QoS (DQOS) support,
   such as specified in the [<a href="#ref-DQOS" title="&quot;PacketCable Dynamic Quality of Service Specification&quot;">DQOS</a>] for cable access networks.  That
   network is connected to a Diffserv core network that uses the
   Resource Management in Diffserv QoS Model [<a href="./rfc5977" title="&quot;RMD-QOSM: The NSIS Quality-of-Service Model for Resource Management in Diffserv&quot;">RFC5977</a>].  On the other
   side of the Diffserv core is a wireless access network built on
   generation "X" technology with QoS support as defined by generation
   "X".  And finally, the handheld endpoint is connected to the wireless
   access network.

   We assume that the laptop is the QNI, and the handheld device is the
   QNR.  The QNI will signal an Initiator QSPEC object to achieve the
   QoS desired on the path.

   The QNI sets QoS Desired, QoS Available, and possibly Minimum QoS
   QSPEC objects in the Initiator QSPEC, and initializes QoS Available
   to QoS Desired.  Each QNE on the path reads and interprets those
   parameters in the Initiator QSPEC and checks to see if QoS Available
   resources can be reserved.  If not, the QNE reduces the respective
   parameter values in QoS Available and reserves these values.  The
   minimum parameter values are given in Minimum QoS, if populated; they
   are zero if Minimum QoS is not included.  If one or more parameters
   in QoS Available fails to satisfy the corresponding minimum values in
   Minimum QoS, the QNE generates a RESPONSE message to the QNI and the
   reservation is aborted.  Otherwise, the QNR generates a RESPONSE to
   the QNI with the QoS Available for the reservation.  If a QNE cannot
   reserve QoS Desired resources, the reservation fails.

   The QNI populates QSPEC parameters to ensure correct treatment of its
   traffic in domains down the path.  Let us assume the QNI wants to
   achieve QoS guarantees similar to IntServ Controlled Load service,
   and also is interested in what path latency it can achieve.
   Additionally, to ensure correct treatment further down the path, the
   QNI includes &lt;PHB Class&gt; in &lt;QoS Desired&gt;.  The QNI therefore
   includes in the QSPEC

      QoS Desired = &lt;TMOD&gt; &lt;PHB Class&gt;
      QoS Available = &lt;TMOD&gt; &lt;Path Latency&gt;

   Since &lt;Path Latency&gt; and &lt;PHB Class&gt; are not vital parameters from
   the QNI's perspective, it does not raise their M flags.

   There are three possibilities when a RESERVE message is received at a
   QNE at a domain border; they are described in the example:

   - the QNE just leaves the QSPEC as is.




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   - the QNE can add a Local QSPEC and encapsulate the Initiator QSPEC
     (see discussion in <a href="#section-4.1">Section 4.1</a>; this is new in QoS NSLP -- RSVP
     does not do this).

   - the QNE can 'hide' the initiator RESERVE message so that only the
     edge QNE processes the initiator RESERVE message, which then
     bypasses intermediate nodes between the edges of the domain and
     issues its own local RESERVE message (see <a href="./rfc5974#section-3.3.1">Section&nbsp;3.3.1 of
     [RFC5974]</a>).  For this new local RESERVE message, the QNE acts as
     the QNI, and the QSPEC in the domain is an Initiator QSPEC.  A
     similar procedure is also used by RSVP in making aggregate
     reservations, in which case there is not a new intra-domain
     (aggregate) RESERVE for each newly arriving inter-domain (per-flow)
     RESERVE, but the aggregate reservation is updated by the border QNE
     (or QNI) as need be.  This is also how RMD works [<a href="./rfc5977" title="&quot;RMD-QOSM: The NSIS Quality-of-Service Model for Resource Management in Diffserv&quot;">RFC5977</a>].

   For example, at the RMD domain, a local RESERVE with its own RMD
   Initiator QSPEC corresponding to the RMD-QOSM is generated based on
   the original Initiator QSPEC according to the procedures described in
   <a href="./rfc5974#section-4.5">Section&nbsp;4.5 of [RFC5974]</a> and in [<a href="./rfc5977" title="&quot;RMD-QOSM: The NSIS Quality-of-Service Model for Resource Management in Diffserv&quot;">RFC5977</a>].  The ingress QNE to the
   RMD domain maps the TMOD parameters contained in the original
   Initiator QSPEC to the equivalent TMOD parameter representing only
   the peak bandwidth in the Local QSPEC.  The local RMD QSPEC for
   example also needs &lt;PHB Class&gt;, which in this case was provided by
   the QNI.

   Furthermore, if the node can, at the egress to the RMD domain, it
   updates QoS Available on behalf of the entire RMD domain.  If it
   cannot (since the M flag is not set for &lt;Path Latency&gt;), it raises
   the parameter-specific, Not Supported N flag, warning the QNR that
   the final latency value in QoS Available is imprecise.

   In the XG domain, the Initiator QSPEC is translated into a local
   QSPEC using a similar procedure as described above.  The Local QSPEC
   becomes the current QSPEC used within the XG domain, and the
   Initiator QSPEC is encapsulated.  This saves the QNEs within the XG
   domain the trouble of re-translating the Initiator QSPEC, and
   simplifies processing in the local domain.  At the egress edge of the
   XG domain, the translated Local QSPEC is removed, and the Initiator
   QSPEC returns to the number one position.

   If the reservation was successful, eventually the RESERVE request
   arrives at the QNR (otherwise, the QNE at which the reservation
   failed aborts the RESERVE and sends an error RESPONSE back to the
   QNI).  If the RII was included in the QoS NSLP message, the QNR
   generates a positive RESPONSE with QSPEC objects QoS Reserved and QoS





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   Available.  The parameters appearing in QoS Reserved are the same as
   in QoS Desired, with values copied from QoS Available.  Hence, the
   QNR includes the following QSPEC objects in the RESPONSE:

      QoS Reserved = &lt;TMOD&gt; &lt;PHB Class&gt;
      QoS Available = &lt;TMOD&gt; &lt;Path Latency&gt;

   If the handheld device on the right of Figure 2 is mobile, and moves
   through different XG wireless networks, then the QoS might change on
   the path since different XG wireless networks might support different
   QOSMs.  As a result, QoS NSLP/QSPEC processing will have to
   renegotiate the QoS Available on the path.  From a QSPEC perspective,
   this is like a new reservation on the new section of the path and is
   basically the same as any other rerouting event -- to the QNEs on the
   new path, it looks like a new reservation.  That is, in this mobile
   scenario, the new segment may support a different QOSM than the old
   segment, and the QNI would now signal a new reservation explicitly
   (or implicitly with the next refreshing RESERVE message) to account
   for the different QOSM in the XG wireless domain.  Further details on
   rerouting are specified in [<a href="./rfc5974" title="&quot;NSIS Signaling Layer Protocol (NSLP) for Quality-of- Service Signaling&quot;">RFC5974</a>].

   For bit-level examples of QSPECs, see the documents specifying QOSMs:
   [<a href="#ref-CL-QOSM" title="&quot;A QoS Model for Signaling IntServ Controlled-Load Service with NSIS&quot;">CL-QOSM</a>], [<a href="./rfc5976" title="&quot;Y.1541-QOSM: Model for Networks Using Y.1541 Quality-of-Service Classes&quot;">RFC5976</a>], and [<a href="./rfc5977" title="&quot;RMD-QOSM: The NSIS Quality-of-Service Model for Resource Management in Diffserv&quot;">RFC5977</a>].

<span class="h2"><a class="selflink" id="section-4" href="#section-4">4</a>.  QSPEC Processing and Procedures</span>

   Three flags are used in QSPEC processing, the M flag, E flag, and N
   flag, which are explained in this section.  The QNI sets the M flag
   for each QSPEC parameter it populates that MUST be interpreted by
   downstream QNEs.  If a QNE does not support the parameter, it sets
   the N flag and fails the reservation.  If the QNE supports the
   parameter but cannot meet the resources requested by the parameter,
   it sets the E flag and fails the reservation.

   If the M flag is not set, the downstream QNE SHOULD interpret the
   parameter.  If the QNE does not support the parameter, it sets the N
   flag and forwards the reservation.  If the QNE supports the parameter
   but cannot meet the resources requested by the parameter, it sets the
   E flag and fails the reservation.

<span class="h3"><a class="selflink" id="section-4.1" href="#section-4.1">4.1</a>.  Local QSPEC Definition and Processing</span>

   A QNE at the edge of a local domain may either a) translate the
   Initiator QSPEC into a Local QSPEC and encapsulate the Initiator
   QSPEC in the RESERVE message, or b) 'hide' the Initiator QSPEC
   through the local domain and reserve resources by generating a new





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   RESERVE message through the local domain containing the Local QSPEC.
   In either case, the Initiator QSPEC parameters are interpreted at the
   local domain edges.

   A Local QSPEC may allow a simpler control plane in a local domain.
   The edge nodes in the local domain must interpret the Initiator QSPEC
   parameters.  They can either initiate a parallel session with Local
   QSPEC or define a Local QSPEC and encapsulate the Initiator QSPEC, as
   illustrated in Figure 3.  The Initiator/Local QSPEC bit identifies
   whether the QSPEC is an Initiator QSPEC or a Local QSPEC.  The QSPEC
   Type indicates, for example, that the initiator of the local QSPEC
   uses to a certain QOSM, e.g., CL-QSPEC Type.  It may be useful for
   the QNI to signal a QSPEC Type based on some QOSM (which will
   necessarily entail populating certain QOSM-related parameters) so
   that a downstream QNE can chose amongst various QOSM-related
   processes it might have.  That is, the QNI populates the QSPEC Type,
   e.g., CL-QSPEC Type and sets the Initiator/Local QSPEC bit to
   'Initiator'.  A local QNE can decide, for whatever reasons, to insert
   a Local QSPEC Type, e.g., RMD-QSPEC Type, and set the local QSPEC
   Type = RMD-QSPEC and set the Initiator/Local QSPEC bit to 'Local'
   (and encapsulate the Initiator QSPEC in the RESERVE or whatever NSLP
   message).

   +--------------------------------+\
   |   QSPEC Type, QSPEC Procedure  | \
   +--------------------------------+ / Common QSPEC Header
   |   Init./Local QSPEC bit=Local  |/
   +================================+\
   |  Local-QSPEC Parameter 1       | \
   +--------------------------------+  \
   |             ....               |   Local-QSPEC Parameters
   +--------------------------------+  /
   |  Local-QSPEC Parameter n       | /
   +--------------------------------+/
   | +----------------------------+ |
   | | QSPEC Type, QSPEC Procedure| |
   | +----------------------------+ |
   | | Init./Local QSPEC bit=Init.| |
   | +============================+ |
   | |                            | | Encapsulated Initiator QSPEC
   | |          ....              | |
   | +----------------------------+ |
   +--------------------------------+

                 Figure 3: Defining a Local QSPEC






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   Here the QoS-NSLP only sees and passes one QSPEC up to the RMF.
   Thus, the type of the QSPEC may change within a local domain.  Hence:

   o  the QNI signals its QoS requirements with the Initiator QSPEC,

   o  the ingress edge QNE in the local domain translates the Initiator
      QSPEC parameters to equivalent parameters in the local QSPEC,

   o  the QNEs in the local domain only interpret the Local QSPEC
      parameters, and

   o  the egress QNE in the local domain processes the Local QSPEC and
      also interprets the QSPEC parameters in the Initiator QSPEC.

   The Local QSPEC MUST be consistent with the Initiator QSPEC.  That
   is, it MUST NOT specify a lower level of resources than specified by
   the Initiator QSPEC.  For example, in RMD the TMOD parameters
   contained in the original Initiator QSPEC are mapped to the
   equivalent TMOD parameter representing only the peak bandwidth in the
   Local QSPEC.

   Note that it is possible to use both a) hiding a QSPEC through a
   local domain by initiating a new RESERVE at the domain edge, and b)
   defining a Local QSPEC and encapsulating the Initiator QSPEC, as
   defined above.  However, it is not expected that both the hiding and
   encapsulating functions would be used at the same time for the same
   flow.

   The support of Local QSPECs is illustrated in Figure 4 for a single
   flow to show where the Initiator and Local QSPECs are used.  The QNI
   initiates an end-to-end, inter-domain QoS NSLP RESERVE message
   containing the Initiator QSPEC for the Y.1541 QOSM.  As illustrated
   in Figure 4, the RESERVE message crosses multiple domains supporting
   different QOSMs.  In this illustration, the Initiator QSPEC arrives
   in a QoS NSLP RESERVE message at the ingress node of the local-QOSM
   domain.  At the ingress edge node of the local-QOSM domain, the end-
   to-end, inter-domain QoS-NSLP message triggers the generation of a
   Local QSPEC, and the Initiator QSPEC is encapsulated within the
   messages signaled through the local domain.  The local QSPEC is used
   for QoS processing in the local-QOSM domain, and the Initiator QSPEC
   is used for QoS processing outside the local domain.

   In this example, the QNI sets &lt;QoS Desired&gt;, &lt;Minimum QoS&gt;, and &lt;QoS
   Available&gt; objects to include objectives for the &lt;Path Latency&gt;,
   &lt;Path Jitter&gt;, and &lt;Path PER&gt; parameters.  The QNE / local domain
   sets the cumulative parameters, e.g., &lt;Path Latency&gt;, that can be
   achieved in the &lt;QoS Available&gt; object (but not less than specified
   in &lt;Minimum QoS&gt;).  If the &lt;QoS Available&gt; fails to satisfy one or



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   more of the &lt;Minimum QoS&gt; objectives, the QNE / local domain notifies
   the QNI and the reservation is aborted.  If any QNE cannot meet the
   requirements designated by the Initiator QSPEC to support a QSPEC
   parameter with the M bit set to zero, the QNE sets the N flag for
   that parameter to one.  Otherwise, the QNR notifies the QNI of the
   &lt;QoS Available&gt; for the reservation.

   |------|   |------|                           |------|   |------|
   | e2e  |&lt;-&gt;| e2e  |&lt;-------------------------&gt;| e2e  |&lt;-&gt;| e2e  |
   | QOSM |   | QOSM |                           | QOSM |   | QOSM |
   |      |   |------|   |-------|   |-------|   |------|   |      |
   | NSLP |   | NSLP |&lt;-&gt;| NSLP  |&lt;-&gt;| NSLP  |&lt;-&gt;| NSLP |   | NSLP |
   |Y.1541|   |local |   |local  |   |local  |   |local |   |Y.1541|
   | QOSM |   | QOSM |   | QOSM  |   | QOSM  |   | QOSM |   | QOSM |
   |------|   |------|   |-------|   |-------|   |------|   |------|
   -----------------------------------------------------------------
   |------|   |------|   |-------|   |-------|   |------|   |------|
   | NTLP |&lt;-&gt;| NTLP |&lt;-&gt;| NTLP  |&lt;-&gt;| NTLP  |&lt;-&gt;| NTLP |&lt;-&gt;| NTLP |
   |------|   |------|   |-------|   |-------|   |------|   |------|
     QNI         QNE        QNE         QNE         QNE       QNR
   (End)  (Ingress Edge) (Interior)  (Interior) (Egress Edge)  (End)

     Figure 4: Example of Initiator and Local Domain QOSM Operation

<span class="h3"><a class="selflink" id="section-4.2" href="#section-4.2">4.2</a>.  Reservation Success/Failure, QSPEC Error Codes, and INFO-SPEC</span>
<span class="h3">      Notification</span>

   A reservation may not be successful for several reasons:

   - a reservation may fail because the desired resources are not
     available.  This is a reservation failure condition.

   - a reservation may fail because the QSPEC is erroneous or because of
     a QNE fault.  This is an error condition.

   A reservation may be successful even though some parameters could not
   be interpreted or updated properly:

   - a QSPEC parameter cannot be interpreted because it is an unknown
     QSPEC parameter type.  This is a QSPEC parameter not supported
     condition.  However, the reservation does not fail.  The QNI can
     still decide whether to keep or tear down the reservation depending
     on the procedures specified by the QNI's QOSM.

   The following sections provide details on the handling of
   unsuccessful reservations and reservations where some parameters
   could not be met, as follows:




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   - details on flags used inside the QSPEC to convey information on
     success or failure of individual parameters.  The formats and
     semantics of all flags are given in <a href="#section-5">Section 5</a>.

   - the content of the INFO-SPEC [<a href="./rfc5974" title="&quot;NSIS Signaling Layer Protocol (NSLP) for Quality-of- Service Signaling&quot;">RFC5974</a>], which carries a code
     indicating the outcome of reservations.

   - the generation of a RESPONSE message to the QNI containing both
     QSPEC and INFO-SPEC objects.

   Note that when there are routers along the path between the QNI and
   QNR where QoS cannot be provided, then the QoS-NSLP generic flag
   BREAK (B) is set.  The BREAK flag is discussed in <a href="./rfc5974#section-3.3.5">Section&nbsp;3.3.5 of
   [RFC5974]</a>.

<span class="h4"><a class="selflink" id="section-4.2.1" href="#section-4.2.1">4.2.1</a>.  Reservation Failure and Error E Flag</span>

   The QSPEC parameters each have a 'reservation failure error E flag'
   to indicate which (if any) parameters could not be satisfied.  When a
   resource cannot be satisfied for a particular parameter, the QNE
   detecting the problem raises the E flag in this parameter.  Note that
   the TMOD parameter and all QSPEC parameters with the M flag set MUST
   be examined by the RMF, and all QSPEC parameters with the M flag not
   set SHOULD be examined by the RMF, and the E flag set to indicate
   whether the parameter could or could not be satisfied.  Additionally,
   the E flag in the corresponding QSPEC object MUST be raised when a
   resource cannot be satisfied for this parameter.  If the reservation
   failure problem cannot be located at the parameter level, only the E
   flag in the QSPEC object is raised.

   When an RMF cannot interpret the QSPEC because the coding is
   erroneous, it raises corresponding reservation failure E flags in the
   QSPEC.  Normally, all QSPEC parameters MUST be examined by the RMF,
   and the erroneous parameters appropriately flagged.  In some cases,
   however, an error condition may occur and the E flag of the error-
   causing QSPEC parameter is raised (if possible), but the processing
   of further parameters may be aborted.

   Note that if the QSPEC and/or any QSPEC parameter is found to be
   erroneous, then any QSPEC parameters not satisfied are ignored and
   the E Flags in the QSPEC object MUST NOT be set for those parameters
   (unless they are erroneous).

   Whether E flags denote reservation failure or error can be determined
   by the corresponding error code in the INFO-SPEC in QoS NSLP, as
   discussed below.





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<span class="h4"><a class="selflink" id="section-4.2.2" href="#section-4.2.2">4.2.2</a>.  QSPEC Parameter Not Supported N Flag</span>

   Each QSPEC parameter has an associated 'Not Supported N flag'.  If
   the Not Supported N flag is set, then at least one QNE along the data
   transmission path between the QNI and QNR cannot interpret the
   specified QSPEC parameter.  A QNE MUST set the Not Supported N flag
   if it cannot interpret the QSPEC parameter.  If the M flag for the
   parameter is not set, the message should continue to be forwarded but
   with the N flag set, and the QNI has the option of tearing down the
   reservation.

   If a QNE in the path does not support a QSPEC parameter, e.g., &lt;Path
   Latency&gt;, and sets the N flag, then downstream QNEs that support the
   parameter SHOULD still update the parameter, even if the N flag is
   set.  However, the presence of the N flag will indicate that the
   cumulative value only provides a bound, and the QNI/QNR decides
   whether or not to accept the reservation with the N flag set.

<span class="h4"><a class="selflink" id="section-4.2.3" href="#section-4.2.3">4.2.3</a>.  INFO-SPEC Coding of Reservation Outcome</span>

   As prescribed by [<a href="./rfc5974" title="&quot;NSIS Signaling Layer Protocol (NSLP) for Quality-of- Service Signaling&quot;">RFC5974</a>], the RESPONSE message always contains the
   INFO-SPEC with an appropriate 'error' code.  It usually also contains
   a QSPEC with QSPEC objects, as described in <a href="#section-4.3">Section 4.3</a> ("QSPEC
   Procedures").  The RESPONSE message MAY omit the QSPEC in case of a
   successful reservation.

   The following guidelines are provided for setting the error codes in
   the INFO-SPEC, based on the codes provided in <a href="./rfc5974#section-5.1.3.6">Section&nbsp;5.1.3.6 of
   [RFC5974]</a>:

   - NSLP error class 2 (Success) / 0x01 (Reservation Success):
     This code is set when all QSPEC parameters have been satisfied.  In
     this case, no E Flag is set; however, one or more N flags may be
     set.

   - NSLP error class 4 (Transient Failure) / 0x07 (Reservation
     Failure):
     This code is set when at least one QSPEC parameter could not be
     satisfied, or when a QSPEC parameter with M flag set could not be
     interpreted.  E flags are set for the parameters that could not be
     satisfied at each QNE up to the QNE issuing the RESPONSE message.
     The N flag is set for those parameters that could not be
     interpreted by at least one QNE.  In this case, QNEs receiving the
     RESPONSE message MUST remove the corresponding reservation.







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   - NSLP error class 3 (Protocol Error) / 0x0c (Malformed QSPEC):
     Some QSPEC parameters had associated errors, E Flags are set for
     parameters that had errors, and the QNE where the error was found
     rejects the reservation.

   - NSLP error class 3 (Protocol Error) / 0x0f (Incompatible QSPEC):
     A higher version QSPEC is signaled and not supported by the QNE.

   - NSLP error class 6 (QoS Model Error):
     QOSM error codes can be defined by QOSM specification documents.  A
     registry is defined in <a href="#section-7">Section 7</a>, IANA Considerations.

<span class="h4"><a class="selflink" id="section-4.2.4" href="#section-4.2.4">4.2.4</a>.  QNE Generation of a RESPONSE Message</span>

   - Successful Reservation Condition

     When a RESERVE message arrives at a QNR and no E Flag is set, the
     reservation is successful.  A RESPONSE message may be generated
     with INFO-SPEC code 'Reservation Success' as described above and in
     <a href="#section-4.3">Section 4.3</a> ("QSPEC Procedures").

   - Reservation Failure Condition

     When a QNE detects that a reservation failure occurs for at least
     one parameter, the QNE sets the E Flags for the QSPEC parameters
     and QSPEC object that failed to be satisfied.  According to
     [<a href="./rfc5974" title="&quot;NSIS Signaling Layer Protocol (NSLP) for Quality-of- Service Signaling&quot;">RFC5974</a>], the QNE behavior depends on whether it is stateful or
     not.  When a stateful QNE determines the reservation failed, it
     formulates a RESPONSE message that includes an INFO-SPEC with the
     'reservation failure' error code and QSPEC object.  The QSPEC in
     the RESPONSE message includes the failed QSPEC parameters marked
     with the E Flag to clearly identify them.

     The default action for a stateless QoS NSLP QNE that detects a
     reservation failure condition is that it MUST continue to forward
     the RESERVE message to the next stateful QNE, with the E Flags
     appropriately set for each QSPEC parameter.  The next stateful QNE
     then formulates the RESPONSE message as described above.

   - Malformed QSPEC Error Condition

     When a stateful QNE detects that one or more QSPEC parameters are
     erroneous, the QNE sets the error code 'malformed QSPEC' in the
     INFO-SPEC.  In this case, the QSPEC object with the E Flags
     appropriately set for the erroneous parameters is returned within
     the INFO-SPEC object.  The QSPEC object can be truncated or fully
     included within the INFO-SPEC.




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     According to [<a href="./rfc5974" title="&quot;NSIS Signaling Layer Protocol (NSLP) for Quality-of- Service Signaling&quot;">RFC5974</a>], the QNE behavior depends on whether it is
     stateful or not.  When a stateful QNE determines a malformed QSPEC
     error condition, it formulates a RESPONSE message that includes an
     INFO-SPEC with the 'malformed QSPEC' error code and QSPEC object.

     The QSPEC in the RESPONSE message includes, if possible, only the
     erroneous QSPEC parameters and no others.  The erroneous QSPEC
     parameter(s) are marked with the E Flag to clearly identify them.
     If QSPEC parameters are returned in the INFO-SPEC that are not
     marked with the E flag, then any values of these parameters are
     irrelevant and MUST be ignored by the QNI.

     The default action for a stateless QoS NSLP QNE that detects a
     malformed QSPEC error condition is that it MUST continue to forward
     the RESERVE message to the next stateful QNE, with the E Flags
     appropriately set for each QSPEC parameter.  The next stateful QNE
     will then act as described in [<a href="./rfc5974" title="&quot;NSIS Signaling Layer Protocol (NSLP) for Quality-of- Service Signaling&quot;">RFC5974</a>].

     A 'malformed QSPEC' error code takes precedence over the
     'reservation failure' error code, and therefore the case of
     reservation failure and QSPEC/RMF error conditions are disjoint,
     and the same E Flag can be used in both cases without ambiguity.

<span class="h4"><a class="selflink" id="section-4.2.5" href="#section-4.2.5">4.2.5</a>.  Special Case of Local QSPEC</span>

     When an unsuccessful reservation problem occurs inside a local
     domain where a Local QSPEC is used, only the topmost (local) QSPEC
     is affected (e.g., E flags are raised, etc.).  The encapsulated
     Initiator QSPEC is untouched.  However, when the message (RESPONSE
     in case of stateful QNEs; RESERVE in case of stateless QNEs)
     reaches the edge of the local domain, the Local QSPEC is removed.
     The edge QNE must update the Initiator QSPEC on behalf of the
     entire domain, reflecting the information received in the Local
     QSPEC.  This update concerns both parameter values and flags.  Note
     that some intelligence is needed in mapping the E flags, etc., from
     the local QSPEC to the Initiator QSPEC.  For example, even if there
     is no direct match between the parameters in the local and
     Initiator QSPECs, E flags could still be raised in the latter.

<span class="h3"><a class="selflink" id="section-4.3" href="#section-4.3">4.3</a>.  QSPEC Procedures</span>

     While the QSPEC template aims to put minimal restrictions on usage
     of QSPEC objects, interoperability between QNEs and between QOSMs
     must be ensured.  We therefore give below an exhaustive list of
     QSPEC object combinations for the message sequences described in
     QoS NSLP [<a href="./rfc5974" title="&quot;NSIS Signaling Layer Protocol (NSLP) for Quality-of- Service Signaling&quot;">RFC5974</a>].  A specific QOSM may prescribe that only a
     subset of the procedures listed below may be used.




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<span class="grey"><a href="./rfc5975">RFC 5975</a>                 QoS NSLP QSPEC Template            October 2010</span>


     Note that QoS NSLP does not mandate the usage of a RESPONSE
     message.  A positive RESPONSE message will only be generated if the
     QNE includes an RII (Request Identification Information) in the
     RESERVE message, and a negative RESPONSE message is always
     generated in case of an error or failure.  Some of the QSPEC
     procedures below, however, are only meaningful when a RESPONSE
     message is possible.  The QNI SHOULD in these cases include an RII.

<span class="h4"><a class="selflink" id="section-4.3.1" href="#section-4.3.1">4.3.1</a>.  Two-Way Transactions</span>

     Here, the QNI issues a RESERVE message, which may be replied to by
     a RESPONSE message.  The following 3 cases for QSPEC object usage
     exist:

     MESSAGE  | OBJECT      | OBJECTS INCLUDED   | OBJECTS INCLUDED
     SEQUENCE | COMBINATION | IN RESERVE MESSAGE | IN RESPONSE MESSAGE
     -----------------------------------------------------------------
     0        | 0           | QoS Desired        | QoS Reserved
              |             |                    |
     0        | 1           | QoS Desired        | QoS Reserved
              |             | QoS Available      | QoS Available
              |             |                    |
     0        | 2           | QoS Desired        | QoS Reserved
              |             | QoS Available      | QoS Available
              |             | Minimum QoS        |

       Table 1: Message Sequence 0: Two-Way Transactions
                Defining Object Combinations 0, 1, and 2

     Case 1:

     If only QoS Desired is included in the RESERVE message, the
     implicit assumption is that exactly these resources must be
     reserved.  If this is not possible, the reservation fails.  The
     parameters in QoS Reserved are copied from the parameters in QoS
     Desired.  If the reservation is successful, the RESPONSE message
     can be omitted in this case.  If a RESPONSE message was requested
     by a QNE on the path, the QSPEC in the RESPONSE message can be
     omitted.

     Case 2:

     When QoS Available is included in the RESERVE message also, some
     parameters will appear only in QoS Available and not in QoS
     Desired.  It is assumed that the value of these parameters is
     collected for informational purposes only (e.g., path latency).





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     However, some parameters in QoS Available can be the same as in QoS
     Desired.  For these parameters, the implicit message is that the
     QNI would be satisfied by a reservation with lower parameter values
     than specified in QoS Desired.  For these parameters, the QNI seeds
     the parameter values in QoS Available to those in QoS Desired
     (except for cumulative parameters such as &lt;Path Latency&gt;).

     Each QNE interprets the parameters in QoS Available according to
     its current capabilities.  Reservations in each QNE are hence based
     on current parameter values in QoS Available (and additionally
     those parameters that only appear in QoS Desired).  The drawback of
     this approach is that, if the resulting resource reservation
     becomes gradually smaller towards the QNR, QNEs close to the QNI
     have an oversized reservation, possibly resulting in unnecessary
     costs for the user.  Of course, in the RESPONSE the QNI learns what
     the actual reservation is (from the QoS RESERVED object) and can
     immediately issue a properly sized refreshing RESERVE.  The
     advantage of the approach is that the reservation is performed in
     half-a-roundtrip time.

     The QSPEC parameter IDs and values included in the QoS Reserved
     object in the RESPONSE message MUST be the same as those in the QoS
     Desired object in the RESERVE message.  For those QSPEC parameters
     that were also included in the QoS Available object in the RESERVE
     message, their value is copied from the QoS Available object (in
     RESERVE) into the QoS Reserved object (in RESPONSE).  For the other
     QSPEC parameters, the value is copied from the QoS Desired object
     (the reservation would fail if the corresponding QoS could not be
     reserved).

     All parameters in the QoS Available object in the RESPONSE message
     are copied with their values from the QoS Available object in the
     RESERVE message (irrespective of whether they have also been copied
     into the QoS Desired object).  Note that the parameters in the QoS
     Available object can be overwritten in the RESERVE message, whereas
     they cannot be overwritten in the RESPONSE message.

     In this case, the QNI SHOULD request a RESPONSE message since it
     will otherwise not learn what QoS is available.

     Case 3:

     This case is handled as case 2, except that the reservation fails
     when QoS Available becomes less than Minimum QoS for one parameter.
     If a parameter appears in the QoS Available object but not in the
     Minimum QoS object, it is assumed that there is no minimum value
     for this parameter.




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<span class="grey"><a href="./rfc5975">RFC 5975</a>                 QoS NSLP QSPEC Template            October 2010</span>


     Regarding Traffic Handling Directives, the default rule is that all
     QSPEC parameters that have been included in the RESERVE message by
     the QNI are also included in the RESPONSE message by the QNR with
     the value they had when arriving at the QNR.  When traveling in the
     RESPONSE message, all Traffic Handling Directives parameters are
     read-only.  Note that a QOSM specification may define its own
     Traffic Handling Directives parameters and processing rules.

<span class="h4"><a class="selflink" id="section-4.3.2" href="#section-4.3.2">4.3.2</a>.  Three-Way Transactions</span>

     Here, the QNR issues a QUERY message that is replied to by the QNI
     with a RESERVE message if the reservation was successful.  The QNR
     in turn sends a RESPONSE message to the QNI.  The following 3 cases
     for QSPEC object usage exist:

     MSG.|OBJ.|OBJECTS INCLUDED |OBJECTS INCLUDED   |OBJECTS INCLUDED
     SEQ.|COM.|IN QUERY MESSAGE |IN RESERVE MESSAGE |IN RESPONSE MESSAGE
     -------------------------------------------------------------------
     1   |0   |QoS Desired      |QoS Desired        |QoS Reserved
         |    |                 |                   |
     1   |1   |QoS Desired      |QoS Desired        |QoS Reserved
         |    |(Minimum QoS)    |QoS Available      |QoS Available
         |    |                 |(Minimum QoS)      |
         |    |                 |                   |
     1   |2   |QoS Desired      |QoS Desired        |QoS Reserved
         |    |QoS Available    |QoS Available      |

       Table 2: Message Sequence 1: Three-Way Transactions
                Defining Object Combinations 0, 1, and 2

     Cases 1 and 2:

     The idea is that the sender (QNR in this scenario) needs to inform
     the receiver (QNI in this scenario) about the QoS it desires.  To
     this end, the sender sends a QUERY message to the receiver
     including a QoS Desired QSPEC object.  If the QoS is negotiable, it
     additionally includes a (possibly zero) Minimum QoS object, as in
     Case 2.

     The RESERVE message includes the QoS Available object if the sender
     signaled that QoS is negotiable (i.e., it included the Minimum QoS
     object).  If the Minimum QoS object received from the sender is
     included in the QUERY message, the QNI also includes the Minimum
     QoS object in the RESERVE message.







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     For a successful reservation, the RESPONSE message in case 1 is
     optional (as is the QSPEC inside).  In case 2, however, the
     RESPONSE message is necessary in order for the QNI to learn about
     the QoS available.

     Case 3:

     This is the 'RSVP-style' scenario.  The sender (QNR in this
     scenario) issues a QUERY message with a QoS Desired object
     informing the receiver (QNI in this scenario) about the QoS it
     desires, as above.  It also includes a QoS Available object to
     collect path properties.  Note that here path properties are
     collected with the QUERY message, whereas in the previous case, 2
     path properties were collected in the RESERVE message.

     Some parameters in the QoS Available object may be the same as in
     the QoS Desired object.  For these parameters, the implicit message
     is that the sender would be satisfied by a reservation with lower
     parameter values than specified in QoS Desired.

     It is possible for the QoS Available object to contain parameters
     that do not appear in the QoS Desired object.  It is assumed that
     the value of these parameters is collected for informational
     purposes only (e.g., path latency).  Parameter values in the QoS
     Available object are seeded according to the sender's capabilities.
     Each QNE remaps or approximately interprets the parameter values
     according to its current capabilities.

     The receiver (QNI in this scenario) signals the QoS Desired object
     as follows: For those parameters that appear in both the QoS
     Available object and QoS Desired object in the QUERY message, it
     takes the (possibly remapped) QSPEC parameter values from the QoS
     Available object.  For those parameters that only appear in the QoS
     Desired object, it adopts the parameter values from the QoS Desired
     object.

     The parameters in the QoS Available QSPEC object in the RESERVE
     message are copied with their values from the QoS Available QSPEC
     object in the QUERY message.  Note that the parameters in the QoS
     Available object can be overwritten in the QUERY message, whereas
     they cannot be overwritten in the RESERVE message.

     The advantage of this model compared to the sender-initiated
     reservation is that the situation of over-reservation in QNEs close
     to the QNI (as described above) does not occur.  On the other hand,
     the QUERY message may find, for example, a particular bandwidth is





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     not available.  When the actual reservation is performed, however,
     the desired bandwidth may meanwhile have become free.  That is, the
     'RSVP style' may result in a smaller reservation than necessary.

     The sender includes all QSPEC parameters it cares about in the
     QUERY message.  Parameters that can be overwritten are updated by
     QNEs as the QUERY message travels towards the receiver.  The
     receiver includes all QSPEC parameters arriving in the QUERY
     message also in the RESERVE message, with the value they had when
     arriving at the receiver.  Again, QOSM-specific QSPEC parameters
     and procedures may be defined in QOSM specification documents.

     Also in this scenario, the QNI SHOULD request a RESPONSE message
     since it will otherwise not learn what QoS is available.

     Regarding Traffic Handling Directives, the default rule is that all
     QSPEC parameters that have been included in the RESERVE message by
     the QNI are also included in the RESPONSE message by the QNR with
     the value they had when arriving at the QNR.  When traveling in the
     RESPONSE message, all Traffic Handling Directives parameters are
     read-only.  Note that a QOSM specification may define its own
     Traffic Handling Directives parameters and processing rules.

<span class="h4"><a class="selflink" id="section-4.3.3" href="#section-4.3.3">4.3.3</a>.  Resource Queries</span>

     Here, the QNI issues a QUERY message in order to investigate what
     resources are currently available.  The QNR replies with a RESPONSE
     message.

     MESSAGE  | OBJECT      | OBJECTS INCLUDED   | OBJECTS INCLUDED
     SEQUENCE | COMBINATION | IN QUERY MESSAGE   | IN RESPONSE MESSAGE
     -----------------------------------------------------------------
     2        | 0           | QoS Available      | QoS Available

           Table 3: Message Sequence 2: Resource Queries
                    Defining Object Combination 0

     Note that the QoS Available object when traveling in the QUERY
     message can be overwritten, whereas in the RESPONSE message it
     cannot be overwritten.

     Regarding Traffic Handling Directives, the default rule is that all
     QSPEC parameters that have been included in the RESERVE message by
     the QNI are also included in the RESPONSE message by the QNR with
     the value they had when arriving at the QNR.  When traveling in the
     RESPONSE message, all Traffic Handling Directives parameters are
     read-only.  Note that a QOSM specification may define its own
     Traffic Handling Directives parameters and processing rules.



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<span class="h4"><a class="selflink" id="section-4.3.4" href="#section-4.3.4">4.3.4</a>.  Bidirectional Reservations</span>

     On a QSPEC level, bidirectional reservations are no different from
     unidirectional reservations, since QSPECs for different directions
     never travel in the same message.

<span class="h4"><a class="selflink" id="section-4.3.5" href="#section-4.3.5">4.3.5</a>.  Preemption</span>

     A flow can be preempted by a QNE based on QNE policy, where a
     decision to preempt a flow may account for various factors such as,
     for example, the values of the QSPEC preemption priority and
     defending priority parameters as described in <a href="#section-5.2.8">Section 5.2.8</a>.  In
     this case, the reservation state for this flow is torn down in the
     QNE, and the QNE sends a NOTIFY message to the QNI, as described in
     [<a href="./rfc5974" title="&quot;NSIS Signaling Layer Protocol (NSLP) for Quality-of- Service Signaling&quot;">RFC5974</a>].  The NOTIFY message carries an INFO-SPEC with the error
     code as described in [<a href="./rfc5974" title="&quot;NSIS Signaling Layer Protocol (NSLP) for Quality-of- Service Signaling&quot;">RFC5974</a>].  A QOSM specification document may
     specify whether a NOTIFY message also carries a QSPEC object.  The
     QNI would normally tear down the preempted reservation by sending a
     RESERVE message with the TEAR flag set using the SII of the
     preempted reservation.  However, the QNI can follow other
     procedures as specified in its QOSM specification document.

<span class="h3"><a class="selflink" id="section-4.4" href="#section-4.4">4.4</a>.  QSPEC Extensibility</span>

     Additional QSPEC parameters MAY need to be defined in the future
     and are defined in separate informational documents.  For example,
     QSPEC parameters are defined in [<a href="./rfc5977" title="&quot;RMD-QOSM: The NSIS Quality-of-Service Model for Resource Management in Diffserv&quot;">RFC5977</a>] and [<a href="./rfc5976" title="&quot;Y.1541-QOSM: Model for Networks Using Y.1541 Quality-of-Service Classes&quot;">RFC5976</a>].

     Guidelines on the technical criteria to be followed in evaluating
     requests for new codepoint assignments for QSPEC objects and QSPEC
     parameters are given in <a href="#section-7">Section 7</a>, IANA Considerations.

<span class="h2"><a class="selflink" id="section-5" href="#section-5">5</a>.  QSPEC Functional Specification</span>

     This section defines the encodings of the QSPEC parameters.  We
     first give the general QSPEC formats and then the formats of the
     QSPEC objects and parameters.

     Network octet order ('big-endian') for all 16- and 32-bit integers,
     as well as 32-bit floating point numbers, is as specified in
     [<a href="./rfc4506" title="&quot;XDR: External Data Representation Standard&quot;">RFC4506</a>], [<a href="#ref-IEEE754" title="&quot;IEEE Standard for Binary Floating-Point Arithmetic&quot;">IEEE754</a>], and [<a href="#ref-NETWORK-OCTET-ORDER">NETWORK-OCTET-ORDER</a>].

<span class="h3"><a class="selflink" id="section-5.1" href="#section-5.1">5.1</a>.  General QSPEC Formats</span>

     The format of the QSPEC closely follows that used in GIST [<a href="./rfc5971" title="&quot;GIST: General Internet Signalling Transport&quot;">RFC5971</a>]
     and QoS NSLP [<a href="./rfc5974" title="&quot;NSIS Signaling Layer Protocol (NSLP) for Quality-of- Service Signaling&quot;">RFC5974</a>].  Every object (and parameter) has the
     following general format:




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   o  The overall format is Type-Length-Value (in that order).

   o  Some parts of the type field are set aside for control flags.

   o  Length has the units of 32-bit words, and measures the length of
      Value.  If there is no Value, Length=0.  The Object length
      excludes the header.

   o  Value is a whole number of 32-bit words.  If there is any padding
      required, the length and location MUST be defined by the object-
      specific format information; objects that contain variable-length
      types may need to include additional length subfields to do so.

   o  Any part of the object used for padding or defined as reserved
      ("r") MUST be set to 0 on transmission and MUST be ignored on
      reception.

   o  Empty QSPECs and empty QSPEC Objects MUST NOT be used.

   o  Duplicate objects, duplicate parameters, and/or multiple
      occurrences of a parameter MUST NOT be used.

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                      Common QSPEC Header                      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      //                       QSPEC Objects                         //
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

<span class="h4"><a class="selflink" id="section-5.1.1" href="#section-5.1.1">5.1.1</a>.  Common Header Format</span>

   The Common QSPEC Header is a fixed 4-octet object containing the
   QSPEC Version, QSPEC Type, an identifier for the QSPEC Procedure (see
   <a href="#section-4.3">Section 4.3</a>), and an Initiator/Local QSPEC bit:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Vers.|I|QSPECType|r|r|  QSPEC Proc.  |        Length         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Vers.: Identifies the QSPEC version number.  QSPEC Version 0 is
          assigned by this specification in <a href="#section-7">Section 7</a> (IANA
          Considerations).






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   QSPEC Type: Identifies the particular type of QSPEC, e.g., a QSPEC
               Type corresponding to a particular QOSM.  QSPEC Type 0
               (default) is assigned by this specification in <a href="#section-7">Section 7</a>
               (IANA Considerations).

   QSPEC Proc.: Identifies the QSPEC procedure and is composed of two
                times 4 bits.  The first field identifies the Message
                Sequence; the second field identifies the QSPEC Object
                Combination used for this particular message sequence:

                 0 1 2 3 4 5 6 7
                +-+-+-+-+-+-+-+-+
                |Mes.Sq |Obj.Cmb|
                +-+-+-+-+-+-+-+-+

                The Message Sequence field can attain the following
                values:

                0: Sender-Initiated Reservations
                1: Receiver-Initiated Reservations
                2: Resource Queries

                The Object Combination field can take the values between
                1 and 3 indicated in the tables in <a href="#section-4.3">Section 4.3</a>:

                Message Sequence: 0
                Object Combination: 0, 1, 2
                Semantic: see Table 1 in <a href="#section-4.3.1">Section 4.3.1</a>

                Message Sequence: 1
                Object Combination: 0, 1, 2
                Semantic: see Table 2 in <a href="#section-4.3.2">Section 4.3.2</a>

                Message Sequence: 2
                Object Combination: 0
                Semantic: see Table 3 in <a href="#section-4.3.3">Section 4.3.3</a>

   I: Initiator/Local QSPEC bit identifies whether the QSPEC is an
      initiator QSPEC or a Local QSPEC, and is set to the following
      values:

               0: Initiator QSPEC
               1: Local QSPEC

   Length: The total length of the QSPEC (in 32-bit words) excluding the
           common header





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<span class="grey"><a href="./rfc5975">RFC 5975</a>                 QoS NSLP QSPEC Template            October 2010</span>


   The QSPEC Objects field is a collection of QSPEC objects (QoS
   Desired, QoS Available, etc.), which share a common format and each
   contain several parameters.

<span class="h4"><a class="selflink" id="section-5.1.2" href="#section-5.1.2">5.1.2</a>.  QSPEC Object Header Format</span>

   QSPEC objects share a common header format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |E|r|r|r|       Object Type     |r|r|r|r|         Length        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   E Flag: Set if an error occurs on object level

   Object Type = 0: QoS Desired (parameters cannot be overwritten)
               = 1: QoS Available (parameters may be overwritten; see
                    <a href="#section-3.2">Section 3.2</a>)
               = 2: QoS Reserved (parameters cannot be overwritten)
               = 3: Minimum QoS (parameters cannot be overwritten)

   The r bits are reserved.

   Each QSPEC or QSPEC parameter within an object is encoded in the same
   way in TLV format using a similar parameter header:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |M|E|N|r|     Parameter ID      |r|r|r|r|         Length        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   M Flag: When set, indicates the subsequent parameter MUST be
           interpreted.  Otherwise, the parameter can be ignored if not
           understood.

   E Flag: When set, indicates either a) a reservation failure where the
           QSPEC parameter is not met, or b) an error occurred when this
           parameter was being interpreted (see <a href="#section-4.2.1">Section 4.2.1</a>).

   N Flag: Not Supported QSPEC parameter flag (see <a href="#section-4.2.2">Section 4.2.2</a>).

   Parameter ID: Assigned consecutively to each QSPEC parameter.
                 Parameter IDs are assigned to each QSPEC parameter
                 defined in this document in Sections <a href="#section-5.2">5.2</a> and <a href="#section-7">7</a> (IANA
                 Considerations).




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<span class="grey"><a href="./rfc5975">RFC 5975</a>                 QoS NSLP QSPEC Template            October 2010</span>


   Parameters are usually coded individually, for example, the &lt;Excess
   Treatment&gt; parameter (<a href="#section-5.2.11">Section 5.2.11</a>).  However, it is also possible
   to combine several sub-parameters into one parameter field, which is
   called 'container coding'.  This coding is useful if either a) the
   sub-parameters always occur together (as for example the 5 sub-
   parameters that jointly make up the TMOD), or b) in order to make
   coding more efficient when the length of each sub-parameter value is
   much less than a 32-bit word (as for example described in [<a href="./rfc5977" title="&quot;RMD-QOSM: The NSIS Quality-of-Service Model for Resource Management in Diffserv&quot;">RFC5977</a>])
   and to avoid header overload.  When a container is defined, the
   Parameter ID and the M, E, and N flags refer to the container.
   Examples of container parameters are &lt;TMOD&gt; (specified below) and the
   PHR (Per Hop Reservation) container parameter specified in [<a href="./rfc5977" title="&quot;RMD-QOSM: The NSIS Quality-of-Service Model for Resource Management in Diffserv&quot;">RFC5977</a>].

<span class="h3"><a class="selflink" id="section-5.2" href="#section-5.2">5.2</a>.  QSPEC Parameter Coding</span>

   The references in the following sections point to the normative
   procedures for processing the QSPEC parameters and sub-parameters.

<span class="h4"><a class="selflink" id="section-5.2.1" href="#section-5.2.1">5.2.1</a>.  &lt;TMOD-1&gt; Parameter</span>

   The &lt;TMOD-1&gt; parameter consists of the &lt;r&gt;, &lt;b&gt;, &lt;p&gt;, &lt;m&gt;, and &lt;MPS&gt;
   sub-parameters [<a href="./rfc2212" title="&quot;Specification of Guaranteed Quality of Service&quot;">RFC2212</a>], which all must be populated in the &lt;TMOD-1&gt;
   parameter.  Note that a second TMOD QSPEC parameter &lt;TMOD-2&gt; is
   specified below in <a href="#section-5.2.2">Section 5.2.2</a>.

   The coding for the &lt;TMOD-1&gt; parameter is as follows:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |1|E|0|r|           1           |r|r|r|r|          5            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  TMOD Rate-1 (r) (32-bit IEEE floating point number)          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  TMOD Size-1 (b) (32-bit IEEE floating point number)          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Peak Data Rate-1 (p) (32-bit IEEE floating point number)     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Minimum Policed Unit-1 (m) (32-bit unsigned integer)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Maximum Packet Size-1 (MPS) (32-bit unsigned integer)        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The &lt;TMOD-1&gt; parameters are represented by three floating point
   numbers in single-precision IEEE floating point format [<a href="#ref-IEEE754" title="&quot;IEEE Standard for Binary Floating-Point Arithmetic&quot;">IEEE754</a>]
   followed by two 32-bit integers in network octet order.  The first
   floating point value is the rate (r), the second floating point value
   is the bucket size (b), the third floating point is the peak rate



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   (p), the first unsigned integer is the minimum policed unit (m), and
   the second unsigned integer is the maximum packet size (MPS).  The
   values of r and p are measured in octets per second; b, m, and MPS
   are measured in octets.  When r, b, and p terms are represented as
   IEEE floating point values, the sign bit MUST be zero (all values
   MUST be non-negative).  Exponents less than 127 (i.e., 0) are
   prohibited.  Exponents greater than 162 (i.e., positive 35) are
   discouraged, except for specifying a peak rate of infinity.  Infinity
   is represented with an exponent of all ones (255), and a sign bit and
   mantissa of all zeroes.

<span class="h4"><a class="selflink" id="section-5.2.2" href="#section-5.2.2">5.2.2</a>.  &lt;TMOD-2&gt; Parameter</span>

   A second QSPEC &lt;TMOD-2&gt; parameter is specified as could be needed,
   for example, to support some Diffserv applications.

   The coding for the &lt;TMOD-2&gt; parameter is as follows:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |M|E|N|r|           2           |r|r|r|r|          5            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  TMOD Rate-2 (r) (32-bit IEEE floating point number)          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  TMOD Size-2 (b) (32-bit IEEE floating point number)          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Peak Data Rate-2 (p) (32-bit IEEE floating point number)     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Minimum Policed Unit-2 (m) (32-bit unsigned integer)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Maximum Packet Size-2 (MPS) (32-bit unsigned integer)        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The &lt;TMOD-2&gt; parameters are represented by three floating point
   numbers in single-precision IEEE floating point format [<a href="#ref-IEEE754" title="&quot;IEEE Standard for Binary Floating-Point Arithmetic&quot;">IEEE754</a>]
   followed by two 32-bit integers in network octet order.  The first
   floating point value is the rate (r), the second floating point value
   is the bucket size (b), the third floating point is the peak rate
   (p), the first unsigned integer is the minimum policed unit (m), and
   the second unsigned integer is the maximum packet size (MPS).  The
   values of r and p are measured in octets per second; b, m, and MPS
   are measured in octets.  When r, b, and p terms are represented as
   IEEE floating point values, the sign bit MUST be zero (all values
   MUST be non-negative).  Exponents less than 127 (i.e., 0) are
   prohibited.  Exponents greater than 162 (i.e., positive 35) are





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   discouraged, except for specifying a peak rate of infinity.  Infinity
   is represented with an exponent of all ones (255), and a sign bit and
   mantissa of all zeroes.

<span class="h4"><a class="selflink" id="section-5.2.3" href="#section-5.2.3">5.2.3</a>.  &lt;Path Latency&gt; Parameter</span>

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |M|E|N|r|           3           |r|r|r|r|          1            |
   +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
   |                Path Latency (32-bit unsigned integer)         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The Path Latency [<a href="./rfc2215" title="&quot;General Characterization Parameters for Integrated Service Network Elements&quot;">RFC2215</a>] is a single 32-bit unsigned integer in
   network octet order.  The intention of the Path Latency parameter is
   the same as the Minimal Path Latency parameter defined in <a href="./rfc2215#section-3.4">Section&nbsp;3.4
   of [RFC2215]</a>.  The purpose of this parameter is to provide a baseline
   minimum path latency for use with services that provide estimates or
   bounds on additional path delay, such as in [<a href="./rfc2212" title="&quot;Specification of Guaranteed Quality of Service&quot;">RFC2212</a>].  Together with
   the queuing delay bound offered by [<a href="./rfc2212" title="&quot;Specification of Guaranteed Quality of Service&quot;">RFC2212</a>] and similar services,
   this parameter gives the application knowledge of both the minimum
   and maximum packet delivery delay.

   The composition rule for the &lt;Path Latency&gt; parameter is summation
   with a clamp of (2^32) - 1 on the maximum value.  The latencies are
   average values reported in units of one microsecond.  A system with
   resolution less than one microsecond MUST set unused digits to zero.
   An individual QNE can add a latency value between 1 and 2^28
   (somewhat over two minutes), and the total latency added across all
   QNEs can range as high as (2^32)-2.  If the sum of the different
   elements delays exceeds (2^32)-2, the end-to-end cumulative delay
   SHOULD be reported as indeterminate = (2^32)-1.  A QNE that cannot
   accurately predict the latency of packets it is processing MUST raise
   the Not Supported N flag and either leave the value of Path Latency
   as is, or add its best estimate of its lower bound.  A raised not-
   supported flag indicates the value of Path Latency is a lower bound
   of the real Path Latency.  The distinguished value (2^32)-1 is taken
   to mean indeterminate latency because the composition function limits
   the composed sum to this value; it indicates the range of the
   composition calculation was exceeded.










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<span class="h4"><a class="selflink" id="section-5.2.4" href="#section-5.2.4">5.2.4</a>.  &lt;Path Jitter&gt; Parameter</span>

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |M|E|N|r|           4           |r|r|r|r|          4            |
   +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
   |    Path Jitter STAT1(variance) (32-bit unsigned integer)      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Path Jitter STAT2(99.9%-ile) (32-bit unsigned integer)     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Path Jitter STAT3(minimum Latency) (32-bit unsigned integer)  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Path Jitter STAT4(Reserved)     (32-bit unsigned integer)  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The Path Jitter is a set of four 32-bit unsigned integers in network
   octet order [<a href="./rfc3393" title="&quot;IP Packet Delay Variation Metric for IP Performance Metrics (IPPM)&quot;">RFC3393</a>, <a href="#ref-Y.1540" title="&quot;Internet Protocol Data Communication Service - IP Packet Transfer and Availability Performance Parameters&quot;">Y.1540</a>, <a href="#ref-Y.1541" title="&quot;Network Performance Objectives for IP-Based Services&quot;">Y.1541</a>].  As noted in <a href="#section-3.3.2">Section 3.3.2</a>,
   the Path Jitter parameter is called "IP Delay Variation" in
   [<a href="./rfc3393" title="&quot;IP Packet Delay Variation Metric for IP Performance Metrics (IPPM)&quot;">RFC3393</a>].  The Path Jitter parameter is the combination of four
   statistics describing the Jitter distribution with a clamp of (2^32)
   - 1 on the maximum of each value.  The jitter STATs are reported in
   units of one microsecond.  A system with resolution less than one
   microsecond MUST set unused digits to zero.  An individual QNE can
   add jitter values between 1 and 2^28 (somewhat over two minutes), and
   the total jitter computed across all QNEs can range as high as
   (2^32)-2.  If the combination of the different element values exceeds
   (2^32)-2, the end-to-end cumulative jitter SHOULD be reported as
   indeterminate.  A QNE that cannot accurately predict the jitter of
   packets it is processing MUST raise the not-supported flag and either
   leave the value of Path Jitter as is, or add its best estimate of its
   STAT values.  A raised not-supported flag indicates the value of Path
   Jitter is a lower bound of the real Path Jitter.  The distinguished
   value (2^32)-1 is taken to mean indeterminate jitter.  A QNE that
   cannot accurately predict the jitter of packets it is processing
   SHOULD set its local Path Jitter parameter to this value.  Because
   the composition function limits the total to this value, receipt of
   this value at a network element or application indicates that the
   true Path Jitter is not known.  This MAY happen because one or more
   network elements could not supply a value or because the range of the
   composition calculation was exceeded.

   NOTE: The Jitter composition function makes use of the &lt;Path Latency&gt;
   parameter.  Composition functions for loss, latency, and jitter may
   be found in [<a href="#ref-Y.1541" title="&quot;Network Performance Objectives for IP-Based Services&quot;">Y.1541</a>].  Development continues on methods to combine
   jitter values to estimate the value of the complete path, and
   additional statistics may be needed to support new methods (the
   methods are standardized in [<a href="./rfc5481" title="&quot;Packet Delay Variation Applicability Statement&quot;">RFC5481</a>] and [<a href="#ref-COMPOSITION" title="&quot;Spacial Composition of Metrics&quot;">COMPOSITION</a>]).



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<span class="h4"><a class="selflink" id="section-5.2.5" href="#section-5.2.5">5.2.5</a>.  &lt;Path PLR&gt; Parameter</span>

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |M|E|N|r|           5           |r|r|r|r|          1            |
   +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
   |             Path Packet Loss Ratio (32-bit floating point)    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The Path PLR is a single 32-bit single precision IEEE floating point
   number in network octet order [<a href="#ref-Y.1541" title="&quot;Network Performance Objectives for IP-Based Services&quot;">Y.1541</a>].  As defined in [<a href="#ref-Y.1540" title="&quot;Internet Protocol Data Communication Service - IP Packet Transfer and Availability Performance Parameters&quot;">Y.1540</a>], Path
   PLR is the ratio of total lost IP packets to total transmitted IP
   packets.  An evaluation interval of 1 minute is suggested in
   [<a href="#ref-Y.1541" title="&quot;Network Performance Objectives for IP-Based Services&quot;">Y.1541</a>], in which the number of losses observed is directly related
   to the confidence in the result.  The composition rule for the &lt;Path
   PLR&gt; parameter is summation with a clamp of 10^-1 on the maximum
   value.  The PLRs are reported in units of 10^-11.  A system with
   resolution less than 10^-11 MUST set unused digits to zero.  An
   individual QNE adds its local PLR value (up to a maximum of 10^-2) to
   the total Path PLR value (up to a maximum of 10^-1) , where the
   acceptability of the total Path PLR value added across all QNEs is
   determined based on the QOSM being used.  The maximum limit of 10^-2
   on a QNE's local PLR value and the maximum limit (clamp value) of
   10^-1 on the accumulated end-to-end Path PLR value are used to
   preserve the accuracy of the simple additive accumulation function
   specified and to avoid more complex accumulation functions.
   Furthermore, if these maximums are exceeded, then the path would
   likely not meet the QoS objectives.  If the sum of the different
   elements' values exceeds 10^-1, the end-to-end cumulative PLR SHOULD
   be reported as indeterminate.  A QNE that cannot accurately predict
   the PLR of packets it is processing MUST raise the not-supported flag
   and either leave the value of Path PLR as is, or add its best
   estimate of its lower bound.  A raised not-supported flag indicates
   the value of Path PLR is a lower bound of the real Path PLR.  The
   distinguished value 10^-1 is taken to mean indeterminate PLR.  A QNE
   that cannot accurately predict the PLR of packets it is processing
   SHOULD set its local path PLR parameter to this value.  Because the
   composition function limits the composed sum to this value, receipt
   of this value at a network element or application indicates that the
   true path PLR is not known.  This MAY happen because one or more
   network elements could not supply a value or because the range of the
   composition calculation was exceeded.








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<span class="h4"><a class="selflink" id="section-5.2.6" href="#section-5.2.6">5.2.6</a>.  &lt;Path PER&gt; Parameter</span>

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |M|E|N|r|           6           |r|r|r|r|          1            |
   +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
   |             Path Packet Error Ratio (32-bit floating point)   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The Path PER is a single 32-bit single precision IEEE floating point
   number in network octet order [<a href="#ref-Y.1541" title="&quot;Network Performance Objectives for IP-Based Services&quot;">Y.1541</a>].  As defined in [<a href="#ref-Y.1540" title="&quot;Internet Protocol Data Communication Service - IP Packet Transfer and Availability Performance Parameters&quot;">Y.1540</a>], Path
   PER is the ratio of total errored IP packets to the total of
   successful IP Packets plus errored IP packets, in which the number of
   errored packets observed is directly related to the confidence in the
   result.  The composition rule for the &lt;Path PER&gt; parameter is
   summation with a clamp of 10^-1 on the maximum value.  The PERs are
   reported in units of 10^-11.  A system with resolution less than
   10^-11 MUST set unused digits to zero.  An individual QNE adds its
   local PER value (up to a maximum of 10^-2) to the total Path PER
   value (up to a maximum of 10^-1) , where the acceptability of the
   total Path PER value added across all QNEs is determined based on the
   QOSM being used.  The maximum limit of 10^-2 on a QNE's local PER
   value and the maximum limit (clamp value) of 10^-1 on the accumulated
   end-to-end Path PER value are used to preserve the accuracy of the
   simple additive accumulation function specified and to avoid more
   complex accumulation functions.  Furthermore, if these maximums are
   exceeded, then the path would likely not meet the QoS objectives.  If
   the sum of the different elements' values exceeds 10^-1, the end-to-
   end cumulative PER SHOULD be reported as indeterminate.  A QNE that
   cannot accurately predict the PER of packets it is processing MUST
   raise the Not Supported N flag and either leave the value of Path PER
   as is, or add its best estimate of its lower bound.  A raised Not
   Supported N flag indicates the value of Path PER is a lower bound of
   the real Path PER.  The distinguished value 10^-1 is taken to mean
   indeterminate PER.  A QNE that cannot accurately predict the PER of
   packets it is processing SHOULD set its local path PER parameter to
   this value.  Because the composition function limits the composed sum
   to this value, receipt of this value at a network element or
   application indicates that the true path PER is not known.  This MAY
   happen because one or more network elements could not supply a value
   or because the range of the composition calculation was exceeded.









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<span class="h4"><a class="selflink" id="section-5.2.7" href="#section-5.2.7">5.2.7</a>.  &lt;Slack Term&gt; Parameter</span>

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |M|E|N|r|           7           |r|r|r|r|          1            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Slack Term (S)  (32-bit unsigned integer)              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Slack term S MUST be nonnegative and is measured in microseconds
   [<a href="./rfc2212" title="&quot;Specification of Guaranteed Quality of Service&quot;">RFC2212</a>].  The Slack term, S, is represented as a 32-bit unsigned
   integer.  Its value can range from 0 to (2^32)-1 microseconds.

<span class="h4"><a class="selflink" id="section-5.2.8" href="#section-5.2.8">5.2.8</a>.  &lt;Preemption Priority&gt; and &lt;Defending Priority&gt; Parameters</span>

   The coding for the &lt;Preemption Priority&gt; and &lt;Defending Priority&gt;
   sub-parameters is as follows [<a href="./rfc3181" title="&quot;Signaled Preemption Priority Policy Element&quot;">RFC3181</a>]:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |M|E|N|r|           8           |r|r|r|r|          1            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Preemption Priority        |      Defending Priority       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Preemption Priority: The priority of the new flow compared with the
      defending priority of previously admitted flows.  Higher values
      represent higher priority.

   Defending Priority: Once a flow is admitted, the preemption priority
      becomes irrelevant.  Instead, its defending priority is used to
      compare with the preemption priority of new flows.

   As specified in [<a href="./rfc3181" title="&quot;Signaled Preemption Priority Policy Element&quot;">RFC3181</a>], &lt;Preemption Priority&gt; and &lt;Defending
   Priority&gt; are 16-bit integer values, and both MUST be populated if
   the parameter is used.













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<span class="h4"><a class="selflink" id="section-5.2.9" href="#section-5.2.9">5.2.9</a>.  &lt;Admission Priority&gt; Parameter</span>

   The coding for the &lt;Admission Priority&gt; parameter is as follows:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |M|E|N|r|           9           |r|r|r|r|          1            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Y.2171 Adm Pri.|Admis. Priority|        (Reserved)             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Two fields are provided for the &lt;Admission Priority&gt; parameter and
   are populated according to the following rules.

   &lt;Y.2171 Admission Priority&gt; values are globally significant on an
   end-to-end basis.  High priority flows, normal priority flows, and
   best-effort priority flows can have access to resources depending on
   their admission priority value, as described in [<a href="#ref-Y.2171" title="&quot;Admission Control Priority Levels in Next Generation Networks&quot;">Y.2171</a>], as follows:

   &lt;Y.2171 Admission Priority&gt;:

   0 - best-effort priority flow
   1 - normal priority flow
   2 - high priority flow

   If the QNI signals &lt;Y.2171 Admission Priority&gt;, it populates both the
   &lt;Y.2171 Admission Priority&gt; and &lt;Admission Priority&gt; fields with the
   same value.  Downstream QNEs MUST NOT change the value in the &lt;Y.2171
   Admission Priority&gt; field so that end-to-end consistency is
   maintained and MUST treat the flow priority according to the value
   populated.  A QNE in a local domain MAY reset a different value of
   &lt;Admission Priority&gt; in a Local QSPEC, but (as specified in <a href="#section-4.1">Section</a>
   <a href="#section-4.1">4.1</a>) the Local QSPEC MUST be consistent with the Initiator QSPEC.
   That is, the local domain MUST specify an &lt;Admission Priority&gt; in the
   Local QSPEC that is functionally equivalent to the &lt;Y.2171 Admission
   Priority&gt; specified by the QNI in the Initiator QSPEC.

   If the QNI signals admission priority according to [EMERGENCY-RSVP],
   it populates a locally significant value in the &lt;Admission Priority&gt;
   field and places all ones in the &lt;Y.2171 Admission Priority&gt; field.
   In this case, the functional significance of the &lt;Admission Priority&gt;
   value is specified by the local network administrator.  Higher values
   indicate higher priority.  Downstream QNEs and RSVP nodes MAY reset
   the &lt;Admission Priority&gt; value according to the local rules specified
   by the local network administrator, but MUST NOT reset the value of
   the &lt;Y.2171 Admission Priority&gt; field.




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   A reservation without an &lt;Y.2171 Admission Priority&gt; parameter MUST
   be treated as a reservation with an &lt;Y.2171 Admission Priority&gt; = 1.

<span class="h4"><a class="selflink" id="section-5.2.10" href="#section-5.2.10">5.2.10</a>.  &lt;RPH Priority&gt; Parameter</span>

   The coding for the &lt;RPH Priority&gt; parameter is as follows:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |M|E|N|r|           10          |r|r|r|r|          1            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         RPH Namespace         | RPH Priority  |   (Reserved)  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   [<a id="ref-RFC4412">RFC4412</a>] defines a resource priority header (RPH) with parameters
   "RPH Namespace" and "RPH Priority", and if populated is applicable
   only to flows with high admission priority.  A registry is created in
   [<a href="./rfc4412" title="&quot;Communications Resource Priority for the Session Initiation Protocol (SIP)&quot;">RFC4412</a>] and extended in [<a href="#ref-EMERG-RSVP" title="&quot;Resource ReSerVation Protocol (RSVP) Extensions for Admission Priority&quot;">EMERG-RSVP</a>] for IANA to assign the RPH
   priority parameter.  In the extended registry, "Namespace Numerical
   Values" are assigned by IANA to RPH Namespaces and "Priority
   Numerical Values" are assigned to the RPH Priority.

   Note that the &lt;Admission Priority&gt; parameter MAY be used in
   combination with the &lt;RPH Priority&gt; parameter, which depends on the
   supported QOSM.  Furthermore, if more than one RPH namespace is
   supported by a QOSM, then the QOSM MUST specify how the mapping
   between the priorities belonging to the different RPH namespaces are
   mapped to each other.

   Note also that additional work is needed to communicate these flow
   priority values to bearer-level network elements
   [<a href="#ref-VERTICAL-INTERFACE">VERTICAL-INTERFACE</a>].

   For the 4 priority parameters, the following cases are permissible
   (procedures specified in references):

   1 parameter:  &lt;Admission Priority&gt; [<a href="#ref-Y.2171" title="&quot;Admission Control Priority Levels in Next Generation Networks&quot;">Y.2171</a>]
   2 parameters: &lt;Admission Priority&gt;, &lt;RPH Priority&gt; [<a href="./rfc4412" title="&quot;Communications Resource Priority for the Session Initiation Protocol (SIP)&quot;">RFC4412</a>]
   2 parameters: &lt;Preemption Priority&gt;, &lt;Defending Priority&gt; [<a href="./rfc3181" title="&quot;Signaled Preemption Priority Policy Element&quot;">RFC3181</a>]
   3 parameters: &lt;Preemption Priority&gt;, &lt;Defending Priority&gt;,
                 &lt;Admission Priority&gt; [<a href="#ref-3GPP-1">3GPP-1</a>, <a href="#ref-3GPP-2">3GPP-2</a>, <a href="#ref-3GPP-3">3GPP-3</a>]
   4 parameters: &lt;Preemption Priority&gt;, &lt;Defending Priority&gt;,
                 &lt;Admission Priority&gt;, &lt;RPH Priority&gt; [3GPP-1, 3GPP-2,
                 3GPP-3]






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   It is permissible to have &lt;Admission Priority&gt; without &lt;RPH
   Priority&gt;, but not permissible to have &lt;RPH Priority&gt; without
   &lt;Admission Priority&gt;.  (Alternatively, &lt;RPH Priority&gt; is ignored in
   instances without &lt;Admission Priority&gt;.)

   Functionality similar to enhanced Multi-Level Precedence and
   Preemption service (eMLPP; as defined in [<a href="#ref-3GPP-1">3GPP-1</a>, <a href="#ref-3GPP-2">3GPP-2</a>]) specifies
   use of &lt;Admission Priority&gt; corresponding to the 'queuing allowed'
   part of eMLPP, as well as &lt;Preemption/Defending Priority&gt;
   corresponding to the 'preemption capable' and 'may be preempted'
   parts of eMLPP.

<span class="h4"><a class="selflink" id="section-5.2.11" href="#section-5.2.11">5.2.11</a>.  &lt;Excess Treatment&gt; Parameter</span>

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |M|E|N|r|           11          |r|r|r|r|          1            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Excess Trtmnt |Re-mark Val|             Reserved              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Excess Treatment: Indicates how the QNE SHOULD process out-of-profile
      traffic, that is, traffic not covered by the &lt;TMOD&gt; parameter.
      The Excess Treatment Parameter is set by the QNI.  Allowed values
      are as follows:

      0: drop
      1: shape
      2: re-mark
      3: no metering or policing is permitted

      If no Excess Treatment Parameter is specified, the default is that
      there are no guarantees to excess traffic, i.e., a QNE can do
      whatever it finds suitable.

      When excess treatment is set to 'drop', all marked traffic MUST be
      dropped by the QNE/RMF.

      When excess treatment is set to 'shape', it is expected that the
      QoS Desired object carries a TMOD parameter, and excess traffic is
      shaped to this TMOD.  The bucket size in the TMOD parameter for
      excess traffic specifies the queuing behavior, and when the
      shaping causes unbounded queue growth at the shaper, any traffic
      in excess of the TMOD for excess traffic SHOULD be dropped.  If
      excess treatment is set to 'shape' and no TMOD parameter is given,
      the E flag is set for the parameter and the reservation fails.  If




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      excess treatment is set to 'shape' and two TMOD parameters are
      specified, then the QOSM specification dictates how excess traffic
      should be shaped in that case.

      When excess treatment is set to 're-mark', the Excess Treatment
      Parameter MUST carry the re-mark value, and the re-mark values and
      procedures MUST be specified in the QOSM specification document.
      For example, packets may be re-marked to pertain to a particular
      QoS class (Diffserv Code Point (DSCP) value).  In the latter case,
      re-marking relates to a Diffserv model where packets arrive marked
      as belonging to a certain QoS class / DSCP, and when they are
      identified as excess, they should then be re-marked to a different
      QoS Class (DSCP value) indicated in the 'Re-mark Value', as
      follows:

   Re-mark Value (6 bits): indicates DSCP value [<a href="./rfc2474" title="&quot;Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers&quot;">RFC2474</a>] to re-mark
      packets to when identified as excess

   If 'no metering or policing is permitted' is signaled, the QNE should
   accept the Excess Treatment Parameter set by the sender with special
   care so that excess traffic should not cause a problem.  To request
   the Null Meter [<a href="./rfc3290" title="&quot;An Informal Management Model for Diffserv Routers&quot;">RFC3290</a>] is especially strong, and should be used
   with caution.

   A NULL metering application [<a href="./rfc2997" title="&quot;Specification of the Null Service Type&quot;">RFC2997</a>] would not include the traffic
   profile, and conceptually it should be possible to support this with
   the QSPEC.  A QSPEC without a traffic profile is not excluded by the
   current specification.  However, note that the traffic profile is
   important even in those cases when the excess treatment is not
   specified, e.g., in negotiating bandwidth for the best-effort
   aggregate.  However, a "NULL Service QOSM" would need to be specified
   where the desired QNE Behavior and the corresponding QSPEC format are
   described.

   As an example behavior for a NULL metering, in the properly
   configured Diffserv router, the resources are shared between the
   aggregates by the scheduling disciplines.  Thus, if the incoming rate
   increases, it will influence the state of a queue within that
   aggregate, while all the other aggregates will be provided sufficient
   bandwidth resources.  NULL metering is useful for best-effort and
   signaling data, where there is no need to meter and police this data
   as it will be policed implicitly by the allocated bandwidth and,
   possibly, active queue management mechanism.








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<span class="h4"><a class="selflink" id="section-5.2.12" href="#section-5.2.12">5.2.12</a>.  &lt;PHB Class&gt; Parameter</span>

   The coding for the &lt;PHB Class&gt; parameter is as follows [<a href="./rfc3140" title="&quot;Per Hop Behavior Identification Codes&quot;">RFC3140</a>]:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |M|E|N|r|           12          |r|r|r|r|          1            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |           PHB Field           |            (Reserved)         |
   +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+

   The above encoding is consistent with [<a href="./rfc3140" title="&quot;Per Hop Behavior Identification Codes&quot;">RFC3140</a>], and the following
   four figures show four possible formats based on the value of the PHB
   Field.

   Single PHB:

       0                   1
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | DSCP      |0 0 0 0 0 0 0 0 0 0|
      +---+---+---+---+---+---+---+---+

   Set of PHBs:

       0                   1
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | DSCP      |0 0 0 0 0 0 0 0 1 0|
      +---+---+---+---+---+---+---+---+

   PHBs not defined by standards action, i.e., experimental or local use
   PHBs as allowed by [<a href="./rfc2474" title="&quot;Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers&quot;">RFC2474</a>].  In this case, an arbitrary 12-bit PHB
   identification code, assigned by the IANA, is placed left-justified
   in the 16-bit field.  Bit 15 is set to 1, and bit 14 is zero for a
   single PHB or 1 for a set of PHBs.  Bits 12 and 13 are zero.

   Single non-standard PHB (experimental or local):

       0                   1
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |      PHB ID CODE      |0 0 0 1|
      +---+---+---+---+---+---+---+---+






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   Set of non-standard PHBs (experimental or local):

       0                   1
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |      PHB ID CODE      |0 0 1 1|
      +---+---+---+---+---+---+---+---+

   Bits 12 and 13 are reserved either for expansion of the PHB
   identification code, or for other use, at some point in the future.

   In both cases, when a single PHBID is used to identify a set of PHBs
   (i.e., bit 14 is set to 1), that set of PHBs MUST constitute a PHB
   Scheduling Class (i.e., use of PHBs from the set MUST NOT cause
   intra-microflow traffic reordering when different PHBs from the set
   are applied to traffic in the same microflow).  The set of AF1x PHBs
   [<a href="./rfc2597" title="&quot;Assured Forwarding PHB Group&quot;">RFC2597</a>] is an example of a PHB Scheduling Class.  Sets of PHBs that
   do not constitute a PHB Scheduling Class can be identified by using
   more than one PHBID.

   The registries needed to use <a href="./rfc3140">RFC 3140</a> already exist; see
   [<a href="#ref-DSCP-REGISTRY" title="&quot;Differentiated Services Field Codepoints&quot;">DSCP-REGISTRY</a>] and [<a href="#ref-PHBID-CODES-REGISTRY">PHBID-CODES-REGISTRY</a>].  Hence, no new registry
   needs to be created for this purpose.

<span class="h4"><a class="selflink" id="section-5.2.13" href="#section-5.2.13">5.2.13</a>.  &lt;DSTE Class Type&gt; Parameter</span>

   A description of the semantic of the parameter values can be found in
   [<a href="./rfc4124" title="&quot;Protocol Extensions for Support of Diffserv-aware MPLS Traffic Engineering&quot;">RFC4124</a>].  The coding for the &lt;DSTE Class Type&gt; parameter is as
   follows:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |M|E|N|r|           13          |r|r|r|r|          1            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |DSTE Cls. Type |                (Reserved)                     |
   +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+

   DSTE Class Type: Indicates the DSTE class type.  Values currently
   allowed are 0, 1, 2, 3, 4, 5, 6, and 7.











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<span class="h4"><a class="selflink" id="section-5.2.14" href="#section-5.2.14">5.2.14</a>.  &lt;Y.1541 QoS Class&gt; Parameter</span>

   The coding for the &lt;Y.1541 QoS Class&gt; parameter [<a href="#ref-Y.1541" title="&quot;Network Performance Objectives for IP-Based Services&quot;">Y.1541</a>] is as
   follows:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |M|E|N|r|           14          |r|r|r|r|          1            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Y.1541 QoS Cls.|                (Reserved)                     |
   +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+

   Y.1541 QoS Class: Indicates the Y.1541 QoS Class.  Values currently
   allowed are 0, 1, 2, 3, 4, 5, 6, and 7.

      Class 0:
      Real-time, highly interactive applications, sensitive to jitter.
      Mean delay &lt;= 100 ms, delay variation &lt;= 50 ms, and loss ratio &lt;=
      10^-3.  Application examples include VoIP and video
      teleconference.

      Class 1:
      Real-time, interactive applications, sensitive to jitter.  Mean
      delay &lt;= 400 ms, delay variation &lt;= 50 ms, and loss ratio &lt;=
      10^-3.  Application examples include VoIP and video
      teleconference.

      Class 2:
      Highly interactive transaction data.  Mean delay &lt;= 100 ms, delay
      variation is unspecified, loss ratio &lt;= 10^-3.  Application
      examples include signaling.

      Class 3:
      Interactive transaction data.  Mean delay &lt;= 400 ms, delay
      variation is unspecified, loss ratio &lt;= 10^-3.  Application
      examples include signaling.

      Class 4:
      Low Loss Only applications.  Mean delay &lt;= 1 s, delay variation is
      unspecified, loss ratio &lt;= 10^-3.  Application examples include
      short transactions, bulk data, and video streaming.

      Class 5:
      Unspecified applications with unspecified mean delay, delay
      variation, and loss ratio.  Application examples include
      traditional applications of default IP networks.




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      Class 6:
      Applications that are highly sensitive to loss.  Mean delay &lt;= 100
      ms, delay variation &lt;= 50 ms, and loss ratio &lt;= 10^-5.
      Application examples include television transport, high-capacity
      TCP transfers, and Time-Division Multiplexing (TDM) circuit
      emulation.

      Class 7:
      Applications that are highly sensitive to loss.  Mean delay &lt;= 400
      ms, delay variation &lt;= 50 ms, and loss ratio &lt;= 10^-5.
      Application examples include television transport, high-capacity
      TCP transfers, and TDM circuit emulation.

<span class="h2"><a class="selflink" id="section-6" href="#section-6">6</a>.  Security Considerations</span>

   QSPEC security is directly tied to QoS NSLP security, and the QoS
   NSLP document [<a href="./rfc5974" title="&quot;NSIS Signaling Layer Protocol (NSLP) for Quality-of- Service Signaling&quot;">RFC5974</a>] has a very detailed security discussion in
   <a href="#section-7">Section 7</a>.  All the considerations detailed in <a href="./rfc5974#section-7">Section&nbsp;7 of [RFC5974]</a>
   apply to QSPEC.

   The priority parameter raises possibilities for theft-of-service
   attacks because users could claim an emergency priority for their
   flows without real need, thereby effectively preventing serious
   emergency calls to get through.  Several options exist for countering
   such attacks, for example:

   - only some user groups (e.g., the police) are authorized to set the
     emergency priority bit

   - any user is authorized to employ the emergency priority bit for
     particular destination addresses (e.g., police)

<span class="h2"><a class="selflink" id="section-7" href="#section-7">7</a>.  IANA Considerations</span>

   This section defines the registries and initial codepoint assignments
   for the QSPEC template, in accordance with <a href="https://www.rfc-editor.org/bcp/bcp26">BCP 26</a>, <a href="./rfc5226">RFC 5226</a>
   [<a href="./rfc5226" title="">RFC5226</a>].  It also defines the procedural requirements to be
   followed by IANA in allocating new codepoints.

   This specification creates the following registries with the
   structures as defined below:

   Object Types (12 bits):
   The following values are allocated as specified in <a href="#section-5">Section 5</a>:
      0: QoS Desired
      1: QoS Available
      2: QoS Reserved
      3: Minimum QoS



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   Further values are as follows:
      4-63: Unassigned
      64-67: Private/Experimental Use
      68-4095: Reserved
      (Note: 'Reserved' just means 'do not give these out'.)
   The registration procedure is Specification Required.

   QSPEC Version (4 bits):
   The following value is allocated by this specification:
      0: Version 0 QSPEC
   Further values are as follows:
      1-15: Unassigned
   The registration procedure is Specification Required.  (A
   specification is required to depreciate, delete, or modify QSPEC
   versions.)

   QSPEC Type (5 bits):
   The following values are allocated by this specification:
      0: Default
      1: Y.1541-QOSM [<a href="./rfc5976" title="&quot;Y.1541-QOSM: Model for Networks Using Y.1541 Quality-of-Service Classes&quot;">RFC5976</a>]
      2: RMD-QOSM [<a href="./rfc5977" title="&quot;RMD-QOSM: The NSIS Quality-of-Service Model for Resource Management in Diffserv&quot;">RFC5977</a>]
   Further values are as follows:
      3-12: Unassigned
      13-16: Local/Experimental Use
      17-31: Reserved
   The registration procedure is Specification Required.

   QSPEC Procedure (8 bits):
   The QSPEC Procedure object consists of the Message Sequence parameter
   (4 bits) and the Object Combination parameter (4 bits), as discussed
   in <a href="#section-4.3">Section 4.3</a>.  Message Sequences 0 (Two-Way Transactions), 1
   (Three-Way Transactions), and 2 (Resource Queries) are explained in
   Sections <a href="#section-4.3.1">4.3.1</a>, <a href="#section-4.3.2">4.3.2</a>, and <a href="#section-4.3.3">4.3.3</a>, respectively.  Tables 1, 2, and 3
   in <a href="#section-4.3">Section 4.3</a> assign the Object Combination Number to Message
   Sequences 0, 1, and 2, respectively.  The values assigned by this
   specification for the Message Sequence parameter and the Object
   Combination parameter are summarized here:














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   MSG.|OBJ.|OBJECTS INCLUDED |OBJECTS INCLUDED   |OBJECTS INCLUDED
   SEQ.|COM.|IN QUERY MESSAGE |IN RESERVE MESSAGE |IN RESPONSE MESSAGE
   -------------------------------------------------------------------
   0   |0   |N/A              |QoS Desired        |QoS Reserved
       |    |                 |                   |
   0   |1   |N/A              |QoS Desired        |QoS Reserved
       |    |N/A              |QoS Available      |QoS Available
       |    |                 |                   |
   0   |2   |N/A              |QoS Desired        |QoS Reserved
       |    |N/A              |QoS Available      |QoS Available
       |    |N/A              |Minimum QoS        |
       |    |                 |                   |
   1   |0   |QoS Desired      |QoS Desired        |QoS Reserved
       |    |                 |                   |
   1   |1   |QoS Desired      |QoS Desired        |QoS Reserved
       |    |(Minimum QoS)    |QoS Available      |QoS Available
       |    |                 |(Minimum QoS)      |
       |    |                 |                   |
   1   |2   |QoS Desired      |QoS Desired        |QoS Reserved
       |    |QoS Available    |QoS Available      |
       |    |                 |                   |
   2   |0   |QoS Available    |N/A                |QoS Available

   Further values of the Message Sequence parameter (4 bits) are as
   follows:
      3-15: Unassigned

   Further values of the Object Combination parameter (4 bits) are as
   follows:

      Message  | Object
      Sequence | Combination
      ---------------------------
        0      | 3-15: Unassigned
        1      | 3-15: Unassigned
        2      | 1-15: Unassigned
        3-15   | 0-15: Unassigned

   The registration procedure is Specification Required.  (A
   specification is required to depreciate, delete, or modify QSPEC
   Procedures.)

   QoS Model Error Code (8 bits):
   QoS Model Error Codes may be defined for NSLP error class 6 (QoS
   Model Error), as described in <a href="./rfc5974#section-6.4">Section&nbsp;6.4 of [RFC5974]</a>.  Values are
   as follows:
      0-63: Unassigned
      64-67: Private/Experimental Use



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      68-255: Reserved
   The registration procedure is Specification Required.  (A
   specification is required to depreciate, delete, or modify QoS Model
   Error Codes.)

   Parameter ID (12 bits):
   The following values are allocated by this specification:
   1-14: assigned as specified in <a href="#section-5.2">Section 5.2</a>:
      1: &lt;TMOD-1&gt;
      2: &lt;TMOD-2&gt;
      3: &lt;Path Latency&gt;
      4: &lt;Path Jitter&gt;
      5: &lt;Path PLR&gt;
      6: &lt;Path PER&gt;
      7: &lt;Slack Term&gt;
      8: &lt;Preemption Priority&gt; and &lt;Defending Priority&gt;
      9: &lt;Admission Priority&gt;
      10: &lt;RPH Priority&gt;
      11: &lt;Excess Treatment&gt;
      12: &lt;PHB Class&gt;
      13: &lt;DSTE Class Type&gt;
      14: &lt;Y.1541 QoS Class&gt;
   Further values are as follows:
      15-255: Unassigned
      256-259: Private/Experimental Use
      260-4095: Reserved
   The registration procedure is Specification Required. (A
   specification is required to depreciate, delete, or modify Parameter
   IDs.)

   Y.2171 Admission Priority Parameter (8 bits):
   The following values are allocated by this specification:
   0-2: assigned as specified in <a href="#section-5.2.9">Section 5.2.9</a>:
      0: best-effort priority flow
      1: normal priority flow
      2: high priority flow
   Further values are as follows:
      3-63: Unassigned
      64-255: Reserved
   The registration procedure is Specification Required.

   RPH Namespace Parameter (16 bits):
   Note that [<a href="./rfc4412" title="&quot;Communications Resource Priority for the Session Initiation Protocol (SIP)&quot;">RFC4412</a>] creates a registry for RPH Namespace and Priority
   values already (see <a href="./rfc4412#section-12.6">Section&nbsp;12.6 of [RFC4412]</a>), and an extension to
   this registry is created in [<a href="#ref-EMERG-RSVP" title="&quot;Resource ReSerVation Protocol (RSVP) Extensions for Admission Priority&quot;">EMERG-RSVP</a>], which will also be used for
   the QSPEC RPH parameter.  In the extended registry, "Namespace
   Numerical Values" are assigned by IANA to RPH Namespaces, and




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   "Priority Numerical Values" are assigned to the RPH Priority.  There
   are no additional IANA requirements made by this specification for
   the RPH Namespace Parameter.

   Excess Treatment Parameter (8 bits):
   The following values are allocated by this specification:
   0-3: assigned as specified in <a href="#section-5.2.11">Section 5.2.11</a>:
      0: drop
      1: shape
      2: re-mark
      3: no metering or policing is permitted
   Further values are as follows:
      4-63: Unassigned
      64-255: Reserved
   The registration procedure is Specification Required.

   Y.1541 QoS Class Parameter (8 bits):
   The following values are allocated by this specification:
   0-7: assigned as specified in <a href="#section-5.2.14">Section 5.2.14</a>:
      0: Y.1541 QoS Class 0
      1: Y.1541 QoS Class 1
      2: Y.1541 QoS Class 2
      3: Y.1541 QoS Class 3
      4: Y.1541 QoS Class 4
      5: Y.1541 QoS Class 5
      6: Y.1541 QoS Class 6
      7: Y.1541 QoS Class 7
   Further values are as follows:
      8-63: Unassigned
      64-255: Reserved
   The registration procedure is Specification Required.

<span class="h2"><a class="selflink" id="section-8" href="#section-8">8</a>.  Acknowledgements</span>

   The authors would like to thank (in alphabetical order) David Black,
   Ken Carlberg, Anna Charny, Christian Dickman, Adrian Farrel, Ruediger
   Geib, Matthias Friedrich, Xiaoming Fu, Janet Gunn, Robert Hancock,
   Chris Lang, Jukka Manner, Martin Stiemerling, An Nguyen, Tom Phelan,
   James Polk, Alexander Sayenko, John Rosenberg, Hannes Tschofenig, and
   Sven van den Bosch for their very helpful suggestions.

<span class="h2"><a class="selflink" id="section-9" href="#section-9">9</a>.  Contributors</span>

   This document is the result of the NSIS Working Group effort.  In
   addition to the authors/editors listed in <a href="#section-12">Section 12</a>, the following
   people contributed to the document:





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   Roland Bless
   Institute of Telematics, Karlsruhe Institute of Technology (KIT)
   Zirkel 2, Building 20.20
   P.O. Box 6980
   Karlsruhe  76049
   Germany
   Phone: +49 721 608 6413
   EMail: bless@kit.edu
   URI: <a href="http://tm.kit.edu/~bless">http://tm.kit.edu/~bless</a>

   Chuck Dvorak
   AT&amp;T
   Room 2A37
   180 Park Avenue, Building 2
   Florham Park, NJ 07932
   Phone: +1 973-236-6700
   Fax: +1 973-236-7453
   EMail: cdvorak@research.att.com

   Yacine El Mghazli
   Alcatel
   Route de Nozay
   91460 Marcoussis cedex
   FRANCE
   Phone: +33 1 69 63 41 87
   EMail: yacine.el_mghazli@alcatel.fr

   Georgios Karagiannis
   University of Twente
   P.O. BOX 217
   7500 AE Enschede
   The Netherlands
   EMail: g.karagiannis@ewi.utwente.nl

   Andrew McDonald
   Siemens/Roke Manor Research
   Roke Manor Research Ltd.
   Romsey, Hants SO51 0ZN
   UK
   EMail: andrew.mcdonald@roke.co.uk











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   Al Morton
   AT&amp;T
   Room D3-3C06
   200 S. Laurel Avenue
   Middletown, NJ 07748
   Phone: +1 732 420-1571
   Fax: +1 732 368-1192
   EMail: acmorton@att.com

   Bernd Schloer
   University of Goettingen
   EMail: bschloer@cs.uni-goettingen.de

   Percy Tarapore
   AT&amp;T
   Room D1-33
   200 S. Laurel Avenue
   Middletown, NJ 07748
   Phone: +1 732 420-4172
   EMail: tarapore@.att.com

   Lars Westberg
   Ericsson Research
   Torshamnsgatan 23
   SE-164 80 Stockholm, Sweden
   EMail: Lars.Westberg@ericsson.com

<span class="h2"><a class="selflink" id="section-10" href="#section-10">10</a>.  Normative References</span>

   [<a id="ref-3GPP-1">3GPP-1</a>]        3GPP TS 22.067 V7.0.0 (2006-03) Technical
                   Specification, 3rd Generation Partnership Project;
                   Technical Specification Group Services and System
                   Aspects; enhanced Multi Level Precedence and
                   Preemption service (eMLPP) - Stage 1 (Release 7).

   [<a id="ref-3GPP-2">3GPP-2</a>]        3GPP TS 23.067 V7.1.0 (2006-03) Technical
                   Specification, 3rd Generation Partnership Project;
                   Technical Specification Group Core Network; enhanced
                   Multi-Level Precedence and Preemption service (eMLPP)
                   - Stage 2 (Release 7).

   [<a id="ref-3GPP-3">3GPP-3</a>]        3GPP TS 24.067 V6.0.0 (2004-12) Technical
                   Specification, 3rd Generation Partnership Project;
                   Technical Specification Group Core Network; enhanced
                   Multi-Level Precedence and Preemption service (eMLPP)
                   - Stage 3 (Release 6).





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<span class="grey"><a href="./rfc5975">RFC 5975</a>                 QoS NSLP QSPEC Template            October 2010</span>


   [<a id="ref-RFC2119">RFC2119</a>]       Bradner, S., "Key words for use in RFCs to Indicate
                   Requirement Levels", <a href="https://www.rfc-editor.org/bcp/bcp14">BCP 14</a>, <a href="./rfc2119">RFC 2119</a>, March 1997.

   [<a id="ref-RFC2210">RFC2210</a>]       Wroclawski, J., "The Use of RSVP with IETF Integrated
                   Services", <a href="./rfc2210">RFC 2210</a>, September 1997.

   [<a id="ref-RFC2212">RFC2212</a>]       Shenker, S., Partridge, C., and R. Guerin,
                   "Specification of Guaranteed Quality of Service", <a href="./rfc2212">RFC</a>
                   <a href="./rfc2212">2212</a>, September 1997.

   [<a id="ref-RFC2215">RFC2215</a>]       Shenker, S. and J. Wroclawski, "General
                   Characterization Parameters for Integrated Service
                   Network Elements", <a href="./rfc2215">RFC 2215</a>, September 1997.

   [<a id="ref-RFC3140">RFC3140</a>]       Black, D., Brim, S., Carpenter, B., and F. Le
                   Faucheur, "Per Hop Behavior Identification Codes",
                   <a href="./rfc3140">RFC 3140</a>, June 2001.

   [<a id="ref-RFC3181">RFC3181</a>]       Herzog, S., "Signaled Preemption Priority Policy
                   Element", <a href="./rfc3181">RFC 3181</a>, October 2001.

   [<a id="ref-RFC4124">RFC4124</a>]       Le Faucheur, F., Ed., "Protocol Extensions for
                   Support of Diffserv-aware MPLS Traffic Engineering",
                   <a href="./rfc4124">RFC 4124</a>, June 2005.

   [<a id="ref-RFC4412">RFC4412</a>]       Schulzrinne, H. and J. Polk, "Communications Resource
                   Priority for the Session Initiation Protocol (SIP)",
                   <a href="./rfc4412">RFC 4412</a>, February 2006.

   [<a id="ref-RFC4506">RFC4506</a>]       Eisler, M., Ed., "XDR: External Data Representation
                   Standard", STD 67, <a href="./rfc4506">RFC 4506</a>, May 2006.

   [<a id="ref-RFC5971">RFC5971</a>]       Schulzrinne, H. and R. Hancock, "GIST: General
                   Internet Signalling Transport", <a href="./rfc5971">RFC 5971</a>, October
                   2010.

   [<a id="ref-RFC5974">RFC5974</a>]       Manner, J., Karagiannis, G., and A. McDonald, "NSIS
                   Signaling Layer Protocol (NSLP) for Quality-of-
                   Service Signaling", <a href="./rfc5974">RFC 5974</a>, October 2010.

   [<a id="ref-Y.1541">Y.1541</a>]        ITU-T Recommendation Y.1541, "Network Performance
                   Objectives for IP-Based Services", February 2006.

   [<a id="ref-Y.2171">Y.2171</a>]        ITU-T Recommendation Y.2171, "Admission Control
                   Priority Levels in Next Generation Networks",
                   September 2006.





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<span class="grey"><a href="./rfc5975">RFC 5975</a>                 QoS NSLP QSPEC Template            October 2010</span>


<span class="h2"><a class="selflink" id="section-11" href="#section-11">11</a>.  Informative References</span>

   [<a id="ref-COMPOSITION">COMPOSITION</a>]   Morton, A. and E. Stephan, "Spacial Composition of
                   Metrics", Work in Progress, July 2010.

   [<a id="ref-DQOS">DQOS</a>]          CableLabs, "PacketCable Dynamic Quality of Service
                   Specification", CableLabs Specification
                   PKT-SP-DQOS-I12-050812, August 2005.

   [<a id="ref-EMERG-RSVP">EMERG-RSVP</a>]    Le Faucheur, F., Polk, J., and K. Carlberg, "Resource
                   ReSerVation Protocol (RSVP) Extensions for Admission
                   Priority", Work in Progress, March 2010.

   [<a id="ref-G.711">G.711</a>]         ITU-T Recommendation G.711, "Pulse code modulation
                   (PCM) of voice frequencies", November 1988.

   [<a id="ref-IEEE754">IEEE754</a>]       Institute of Electrical and Electronics Engineers,
                   "IEEE Standard for Binary Floating-Point Arithmetic",
                   ANSI/IEEE Standard 754-1985, August 1985.

   [<a id="ref-CL-QOSM">CL-QOSM</a>]       Kappler, C., "A QoS Model for Signaling IntServ
                   Controlled-Load Service with NSIS", Work in Progress,
                   April 2010.

   [<a id="ref-DSCP-REGISTRY">DSCP-REGISTRY</a>] IANA, "Differentiated Services Field Codepoints",
                   <a href="http://www.iana.org">http://www.iana.org</a>.

   [<a id="ref-NETWORK-OCTET-ORDER">NETWORK-OCTET-ORDER</a>]
                   Wikipedia, "Endianness",
                   <a href="http://en.wikipedia.org/wiki/Endianness">http://en.wikipedia.org/wiki/Endianness</a>.

   [<a id="ref-PHBID-CODES-REGISTRY">PHBID-CODES-REGISTRY</a>]
                   IANA, "Per Hop Behavior Identification Codes",
                   <a href="http://www.iana.org">http://www.iana.org</a>.

   [<a id="ref-RFC1701">RFC1701</a>]       Hanks, S., Li, T., Farinacci, D., and P. Traina,
                   "Generic Routing Encapsulation (GRE)", <a href="./rfc1701">RFC 1701</a>,
                   October 1994.

   [<a id="ref-RFC1702">RFC1702</a>]       Hanks, S., Li, T., Farinacci, D., and P. Traina,
                   "Generic Routing Encapsulation over IPv4 networks",
                   <a href="./rfc1702">RFC 1702</a>, October 1994.

   [<a id="ref-RFC2003">RFC2003</a>]       Perkins, C., "IP Encapsulation within IP", <a href="./rfc2003">RFC 2003</a>,
                   October 1996.

   [<a id="ref-RFC2004">RFC2004</a>]       Perkins, C., "Minimal Encapsulation within IP", <a href="./rfc2004">RFC</a>
                   <a href="./rfc2004">2004</a>, October 1996.



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<span class="grey"><a href="./rfc5975">RFC 5975</a>                 QoS NSLP QSPEC Template            October 2010</span>


   [<a id="ref-RFC2205">RFC2205</a>]       Braden, R., Ed., Zhang, L., Berson, S., Herzog, S.,
                   and S. Jamin, "Resource ReSerVation Protocol (RSVP)
                   -- Version 1 Functional Specification", <a href="./rfc2205">RFC 2205</a>,
                   September 1997.

   [<a id="ref-RFC2473">RFC2473</a>]       Conta, A. and S. Deering, "Generic Packet Tunneling
                   in IPv6 Specification", <a href="./rfc2473">RFC 2473</a>, December 1998.

   [<a id="ref-RFC2474">RFC2474</a>]       Nichols, K., Blake, S., Baker, F., and D. Black,
                   "Definition of the Differentiated Services Field (DS
                   Field) in the IPv4 and IPv6 Headers", <a href="./rfc2474">RFC 2474</a>,
                   December 1998.

   [<a id="ref-RFC2475">RFC2475</a>]       Blake, S., Black, D., Carlson, M., Davies, E., Wang,
                   Z., and W. Weiss, "An Architecture for Differentiated
                   Service", <a href="./rfc2475">RFC 2475</a>, December 1998.

   [<a id="ref-RFC2597">RFC2597</a>]       Heinanen, J., Baker, F., Weiss, W., and J.
                   Wroclawski, "Assured Forwarding PHB Group", <a href="./rfc2597">RFC 2597</a>,
                   June 1999.

   [<a id="ref-RFC2697">RFC2697</a>]       Heinanen, J. and R. Guerin, "A Single Rate Three
                   Color Marker", <a href="./rfc2697">RFC 2697</a>, September 1999.

   [<a id="ref-RFC2997">RFC2997</a>]       Bernet, Y., Smith, A., and B. Davie, "Specification
                   of the Null Service Type", <a href="./rfc2997">RFC 2997</a>, November 2000.

   [<a id="ref-RFC3290">RFC3290</a>]       Bernet, Y., Blake, S., Grossman, D., and A. Smith,
                   "An Informal Management Model for Diffserv Routers",
                   <a href="./rfc3290">RFC 3290</a>, May 2002.

   [<a id="ref-RFC3393">RFC3393</a>]       Demichelis, C. and P. Chimento, "IP Packet Delay
                   Variation Metric for IP Performance Metrics (IPPM)",
                   <a href="./rfc3393">RFC 3393</a>, November 2002.

   [<a id="ref-RFC3550">RFC3550</a>]       Schulzrinne, H., Casner, S., Frederick, R., and V.
                   Jacobson, "RTP: A Transport Protocol for Real-Time
                   Applications", STD 64, <a href="./rfc3550">RFC 3550</a>, July 2003.

   [<a id="ref-RFC3564">RFC3564</a>]       Le Faucheur, F. and W. Lai, "Requirements for Support
                   of Differentiated Services-aware MPLS Traffic
                   Engineering", <a href="./rfc3564">RFC 3564</a>, July 2003.

   [<a id="ref-RFC4213">RFC4213</a>]       Nordmark, E. and R. Gilligan, "Basic Transition
                   Mechanisms for IPv6 Hosts and Routers", <a href="./rfc4213">RFC 4213</a>,
                   October 2005.

   [<a id="ref-RFC4301">RFC4301</a>]       Kent, S. and K. Seo, "Security Architecture for the



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                   Internet Protocol", <a href="./rfc4301">RFC 4301</a>, December 2005.

   [<a id="ref-RFC4303">RFC4303</a>]       Kent, S., "IP Encapsulating Security Payload (ESP)",
                   <a href="./rfc4303">RFC 4303</a>, December 2005.

   [<a id="ref-RFC5226">RFC5226</a>]       Narten, T. and H. Alvestrand, "Guidelines for Writing
                   an IANA Considerations Section in RFCs", <a href="https://www.rfc-editor.org/bcp/bcp26">BCP 26</a>, <a href="./rfc5226">RFC</a>
                   <a href="./rfc5226">5226</a>, May 2008.

   [<a id="ref-RFC5481">RFC5481</a>]       Morton, A. and B. Claise, "Packet Delay Variation
                   Applicability Statement", <a href="./rfc5481">RFC 5481</a>, March 2009.

   [<a id="ref-RFC5976">RFC5976</a>]       Ash, G., Morton, A., Dolly, M., Tarapore, P., Dvorak,
                   C., and Y.  El Mghazli, "Y.1541-QOSM: Model for
                   Networks Using Y.1541 Quality-of-Service Classes",
                   <a href="./rfc5976">RFC 5976</a>, October 2010.

   [<a id="ref-RFC5977">RFC5977</a>]       Bader, A., Westberg, L., Karagiannis, G., Kappler, C,
                   and T. Phelan, "RMD-QOSM: The NSIS Quality-of-Service
                   Model for Resource Management in Diffserv", <a href="./rfc5977">RFC 5977</a>,
                   October 2010.

   [<a id="ref-VERTICAL-INTERFACE">VERTICAL-INTERFACE</a>]
                   Dolly, M., Tarapore, P., and S. Sayers, "Discussion
                   on Associating of Control Signaling Messages with
                   Media Priority Levels", T1S1.7 and PRQC, October
                   2004.

   [<a id="ref-Y.1540">Y.1540</a>]        ITU-T Recommendation Y.1540, "Internet Protocol Data
                   Communication Service - IP Packet Transfer and
                   Availability Performance Parameters", December 2002.




















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<span class="h2"><a class="selflink" id="appendix-A" href="#appendix-A">Appendix A</a>.  Mapping of QoS Desired, QoS Available, and QoS Reserved of</span>
             NSIS onto AdSpec, TSpec, and RSpec of RSVP IntServ

   The union of QoS Desired, QoS Available, and QoS Reserved can provide
   all functionality of the objects specified in RSVP IntServ; however,
   it is difficult to provide an exact mapping.

   In RSVP, the Sender TSpec specifies the traffic an application is
   going to send (e.g., TMOD).  The AdSpec can collect path
   characteristics (e.g., delay).  Both are issued by the sender.  The
   receiver sends the FlowSpec that includes a Receiver TSpec describing
   the resources reserved using the same parameters as the Sender TSpec,
   as well as an RSpec that provides additional IntServ QoS Model
   specific parameters, e.g., Rate and Slack.

   The RSVP TSpec, AdSpec, and RSpec are tailored to the receiver-
   initiated signaling employed by RSVP and the IntServ QoS Model.  For
   example, to the knowledge of the authors, it is not possible for the
   sender to specify a desired maximum delay except implicitly and
   mutably by seeding the AdSpec accordingly.  Likewise, the RSpec is
   only meaningfully sent in the receiver-issued RSVP RESERVE message.
   For this reason, our discussion at this point leads us to a slightly
   different mapping of necessary functionality to objects, which should
   result in more flexible signaling models.

<span class="h2"><a class="selflink" id="appendix-B" href="#appendix-B">Appendix B</a>.  Example of TMOD Parameter Encoding</span>

   In an example VoIP application that uses RTP [<a href="./rfc3550" title="&quot;RTP: A Transport Protocol for Real-Time Applications&quot;">RFC3550</a>] and the G.711
   Codec [<a href="#ref-G.711" title="&quot;Pulse code modulation (PCM) of voice frequencies&quot;">G.711</a>], the TMOD-1 parameter could be set as follows:

   In the simplest case, the Minimum Policed Unit m is the sum of the
   IP, UDP, and RTP headers + payload.  The IP header in the IPv4 case
   has a size of 20 octets (40 octets if IPv6 is used).  The UDP header
   has a size of 8 octets, and RTP uses a 12-octet header.  The G.711
   Codec specifies a bandwidth of 64 kbit/s (8000 octets/s).  Assuming
   RTP transmits voice datagrams every 20 ms, the payload for one
   datagram is 8000 octets/s * 0.02 s = 160 octets.

   IPv4 + UDP + RTP + payload: m = 20 + 8 + 12 + 160 octets = 200 octets
   IPv6 + UDP + RTP + payload: m = 40 + 8 + 12 + 160 octets = 220 octets

   The Rate r specifies the amount of octets per second.  50 datagrams
   are sent per second.

   IPv4: r = 50 1/s * m = 10,000 octets/s
   IPv6: r = 50 1/s * m = 11,000 octets/s





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   The bucket size b specifies the maximum burst.  In this example, a
   burst of 10 packets is used.

   IPv4: b = 10 * m = 2000 octets
   IPv6: b = 10 * m = 2200 octets

   A number of extra headers (e.g., for encapsulation) may be included
   in the datagram.  A non-exhaustive list is given below.  For
   additional headers, m, r, and b have to be set accordingly.

   Protocol Header Size
   --------------------------+------------
   GRE [<a href="./rfc1701" title="&quot;Generic Routing Encapsulation (GRE)&quot;">RFC1701</a>]             |    8 octets
   GREIP4 [<a href="./rfc1702" title="&quot;Generic Routing Encapsulation over IPv4 networks&quot;">RFC1702</a>]          |  4-8 octets
   IP4INIP4 [<a href="./rfc2003" title="&quot;IP Encapsulation within IP&quot;">RFC2003</a>]        |   20 octets
   MINENC [<a href="./rfc2004" title="&quot;Minimal Encapsulation within IP&quot;">RFC2004</a>]          | 8-12 octets
   IP6GEN [<a href="./rfc2473" title="&quot;Generic Packet Tunneling in IPv6 Specification&quot;">RFC2473</a>]          |   40 octets
   IP6INIP4 [<a href="./rfc4213" title="&quot;Basic Transition Mechanisms for IPv6 Hosts and Routers&quot;">RFC4213</a>]        |   20 octets
   IPsec [RFC4301, <a href="./rfc4303">RFC4303</a>]  |    variable
   --------------------------+------------































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Authors' Addresses

   Gerald Ash (Editor)
   AT&amp;T
   EMail: gash5107@yahoo.com


   Attila Bader (Editor)
   Traffic Lab
   Ericsson Research
   Ericsson Hungary Ltd.
   Laborc u. 1 H-1037
   Budapest Hungary
   EMail: Attila.Bader@ericsson.com


   Cornelia Kappler (Editor)
   ck technology concepts
   Berlin, Germany
   EMail: cornelia.kappler@cktecc.de


   David R. Oran (Editor)
   Cisco Systems, Inc.
   7 Ladyslipper Lane
   Acton, MA 01720, USA
   EMail:  oran@cisco.com
























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