One document matched: draft-dhody-pce-stateful-pce-auto-bandwidth-04.xml


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<rfc ipr="trust200902" category="std" docName="draft-dhody-pce-stateful-pce-auto-bandwidth-04" obsoletes="" updates="" submissionType="IETF" xml:lang="en">
  <front>
    <title abbrev="AUTO-BW">PCEP Extensions for MPLS-TE LSP Automatic Bandwidth Adjustment with stateful PCE</title>
    <author initials="D" surname="Dhody" fullname="Dhruv Dhody">
      <organization>Huawei Technologies</organization>
      <address>
        <postal>
          <street>Divyashree Techno Park, Whitefield</street>
          <city>Bangalore</city>
          <region>Karnataka</region>
          <code>560037</code>
          <country>India</country>
        </postal>
        <email>dhruv.ietf@gmail.com</email>
      </address>
    </author>
    <author initials="U" surname="Palle" fullname="Udayasree Palle">
      <organization>Huawei Technologies</organization>
      <address>
        <postal>
          <street>Divyashree Techno Park, Whitefield</street>
          <city>Bangalore</city>
          <region>Karnataka</region>
          <code>560037</code>
          <country>India</country>
        </postal>
        <email>udayasree.palle@huawei.com</email>
      </address>
    </author>
    <author initials="R" surname="Singh" fullname="Ravi Singh">
      <organization>Juniper Networks</organization>
      <address>
        <postal>
          <street>1194 N. Mathilda Ave.</street>
          <city>Sunnyvale</city>
          <region>CA</region>
          <code>94089</code>
          <country>USA</country>
        </postal>
        <email>ravis@juniper.net</email>
      </address>
    </author>
    <date month="March" year="2015" />
    <area>Routing</area>
    <workgroup>PCE Working Group</workgroup>
    <abstract>
      <t>The Path Computation Element Communication Protocol (PCEP) 
      provides mechanisms for Path Computation Elements (PCEs) to 
      perform path computations in response to Path Computation 
      Clients (PCCs) requests. The stateful PCE extensions provide 
      stateful control of 
      Multiprotocol Label Switching (MPLS) Traffic Engineering 
      Label Switched Paths (TE LSP) via PCEP, for a model where 
      the PCC delegates control over one or more locally 
      configured LSPs to the PCE.</t>
      <t>This document describes the automatic bandwidth adjustment 
      of such LSPs under the Active Stateful PCE model.</t>
    </abstract>
  </front>
  <middle>
    <section title="Introduction" toc="default">
        <t><xref target="RFC5440"/> describes the Path Computation 
        Element Protocol (PCEP) as the communication between a Path 
        Computation Client (PCC) and a Path Control Element (PCE), 
        or between PCE and PCE, enabling computation of Multiprotocol 
        Label Switching (MPLS) for Traffic Engineering Label Switched 
        Path (TE LSP).</t>
        <t><xref target='I-D.ietf-pce-stateful-pce'/> specifies extensions to PCEP 
        to enable stateful control of MPLS TE LSPs. In this document focus 
        is on Active Stateful PCE where LSPs are configured on the PCC 
        and control over them is delegated to the PCE.</t>
        <t>Over time, based on the varying traffic pattern, an LSP 
        established with certain bandwidth may require to adjust the 
        reserved bandwidth over time automatically. Ingress Label Switch 
        Router (LSR) samples the traffic rate at each sample-interval (BwSample) to 
        determine the traffic information as Maximum Average Bandwidth 
        (MaxAvgBw). Further adjustment to the reserved bandwidth should be 
        made at every adjustment-interval automatically.</t>
        <t>Enabling Auto-Bandwidth on a LSP results in the LSP automatically 
        adjusting its bandwidth based on the actual traffic flowing through 
        the LSP. A LSP can therefore be setup with some arbitrary (or zero) 
        bandwidth value such that the LSP automatically monitors the traffic 
        flow and adjusts its bandwidth every adjustment-interval period. 
        The bandwidth adjustment uses the make-before-break signaling method 
        so that there is no interruption to traffic flow. This is described 
        in detail in <xref target="sec_auto"/>. 
        <xref target='I-D.ietf-pce-stateful-pce-app'/> describes the usecase for 
        auto-bandwidth adjustment for passive and active stateful PCE.</t>
        
        <t>There are two approaches to automatic bandwidth adjustments
        in case of active stateful PCE - 
        <list style="symbols">
        <t>PCE to decide adjusted bandwidth:
        <list style="symbols">
        <t>Active 
        stateful PCE can use other information such as historical trending data, 
        application-specific information about expected demands and central policy 
        information along with realtime actual flow volumes to make smarter 
        bandwidth adjustment to delegated LSPs. Since LSP has delegated control to the PCE,
        it is inherently suited that it should be stateful PCE that decides the 
        bandwidth adjustments. But this requires PCC to report the realtime bandwidth usage
        as well as the configuration knobs etc.</t>
        </list>
        </t>
        <t>PCC to decide adjusted bandwidth:
        <list style="symbols">
        <t>This approach would be similar to passive stateful PCE model, where 
        the headend (PCC) monitor and calculate the new adjusted bandwidth 
        and request the computed adjusted bandwidth to be updated. The 
        passive stateful PCE would use path request/reply mechanism where
        as in active stateful PCE report/update mechanism is used to adjust
        the bandwidth. This approach only require PCC to report the calculated
        bandwidth to be adjusted. But this approach does not utilize the
        optimization advantages offered by the active stateful PCE.
        </t>
        </list>
        </t>
        </list>
        </t>
        
        
        

        <t>This document defines extensions needed to support Auto-Bandwidth 
        feature along with mechanism to provide traffic information of the 
        LSPs in a stateful PCE model using PCEP.</t>
        <t>This document does not exclude use of any other 
        mechanism employed by stateful PCE to learn real time traffic information
        etc. But at the same time, using the same protocol (PCEP in this case) for 
        updating and reporting the LSP parameters as well as to support automatic
        bandwidth adjustment is operationally beneficial.</t> 
      <section title="Requirements Language" toc="default">
        <t>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 <xref target="RFC2119"/>.</t>
      </section>
    </section>
    <section title="Terminology" toc="default">
      <t>The following terminology is used in this document.</t>
      <t>
        <list style="hanging">
          <t hangText="Active Stateful PCE:">PCE that uses tunnel state 
          information learned from PCCs to optimize path computations.  
          Additionally, it actively updates tunnel parameters in those 
          PCCs that delegated control over their tunnels to the PCE.</t>
          <t hangText="Delegation:">:An operation to grant a PCE temporary
          rights to modify a subset of tunnel parameters on one or more 
          PCC's tunnels.  Tunnels are delegated from a PCC to a PCE.</t>
          <t hangText="PCC:">Path Computation Client: any client application 
          requesting a path computation to be performed by a Path 
          Computation Element.</t>
          <t hangText="PCE:">Path Computation Element.  An entity (component, 
          application, or network node) that is capable of computing a 
          network path or route based on a network graph and applying 
          computational constraints.</t>
          <t hangText="TE LSP:">Traffic Engineering Label Switched Path.</t>
        </list>
      </t>
      <t>Note the additional terms defined in <xref target="sec_auto"/>.</t>
    </section>
    <section title="Motivation" toc="default">
    <t>An active stateful PCE can update the bandwidth for a delegated 
    LSP via mechanisms described in <xref target='I-D.ietf-pce-stateful-pce'/>. 
    Note that further extension are needed because of following
    reasons: </t>
        <t>
        <list style="numbers">
        <t>To identify the LSPs that would like to use this feature.
        Not all LSPs in some deployments would like their bandwidth
        to be dependent on the live traffic but be constant as set by
        the operator. Incase of PCC initiated LSP, they would be
        configured at PCC and PCEP should support a mechanism to 
        identify the LSP with auto bandwidth feature enabled at the PCE. 
        Where as for PCE initiated LSP, PCEP should support mechanims to
        request PCC to provide live traffic information.</t>
        <t>Further for LSP with auto bandwidth feature enabled, operator should 
        be able to specify the knobs to control this feature like 
        the bandwidth-range etc and PCEP should support their encoding.</t>
        <t>PCC would need to report the live traffic information using 
        the same protocol (PCEP in this case) making the network 
        operations easier.</t>
        </list>
        </t>
        <t>Extensions as specified in this document is one of the way for 
        PCE to learn this information. But at the same time a stateful 
        PCE MAY choose to learn this 
        information from other means like management, performance tools.</t>
    </section>
    <section title="Architectural Overview" toc="default">
      <section title="Auto-Bandwidth Overview" toc="default" anchor="sec_auto">
        <t>Auto-Bandwidth feature allows an LSP to automatically and dynamically 
        adjust its reserved bandwidth over time, i.e. without network operator 
        intervention. The bandwidth adjustment uses the make-before-break adaptive 
        signaling method so that there is no interruption to traffic flow.</t>
        <t>The new bandwidth reservation is determined by sampling the actual traffic 
        flowing through the LSP. If the traffic flowing through the LSP is lower than 
        the configured or current bandwidth of the LSP, the extra bandwidth is being 
        reserved needlessly and being wasted. Conversely, if the actual traffic flowing 
        through the LSP is higher than the configured or current bandwidth of the LSP, 
        it can potentially cause congestion or packet loss. With Auto-Bandwidth feature, 
        the LSP bandwidth can be set to some arbitrary value (even zero) during initial 
        setup time, and it will be periodically adjusted over time based on the actual 
        bandwidth requirement.</t>
        <t>Note the following terms:</t>
        <t>
        <list style="hanging">
          <t hangText="Maximum Average Bandwidth (MaxAvgBw):">The maximum average 
          bandwidth is the unit to measure the current traffic demand between a 
          time interval. This is the maximum value of the averaged traffic pattern 
          in a particular time interval.</t>
          <t hangText="Sample-Interval:">The time interval in which the traffic 
          rate is collected as a sample.</t> 
          <t hangText="Adjustment-Interval:">The time interval in which the 
          bandwidth adjustment should be made based on the MaxAvgBw.</t>
          <t hangText="Minimum Bandwidth:">The minimum bandwidth that should 
          be reserved for the LSP.</t>
          <t hangText="Maximum Bandwidth:">The maximum bandwidth that can be 
          reserved for the LSP.</t>
          <t hangText="Report-Threshold:">This value indicates when the current 
		  live traffic bandwidth sample (BwSample)		  
          must be reported to stateful PCE via PCRpt message. Only if the percentage 
          difference between the current BwSample and the last BwSample is greater 
          than or equal to the threshold percentage the LSP bandwidth is reported to 
          PCE.</t>
          <t hangText="Adjust-Threshold:">This value indicates when the bandwidth 
          must be adjusted. Only if the percentage difference between the current 
          MaxAvgBw  and the current bandwidth allocation is greater than or equal 
          to the threshold percentage the LSP bandwidth is adjusted to the current 
          bandwidth demand.</t>
        </list>
    </t>   
      </section>
      <section title="Deploying Auto-Bandwidth Feature" toc="default">
        <t>The traffic rate is repeatedly sampled at each sample-interval 
        (which can be configured by the user and the default value as 5 minutes). 
        The sampled traffic rates are accumulated over the adjustment-interval 
        period (which can be configured by the user and the default value as 
        24 hours).</t> 
        <t>The ingress LSR reports the live traffic information to the stateful PCE 
        via the PCRpt message, to avoid multiple reports, the Report-Threshold 
        percentage is used. Only if the percentage difference between the current 
        BwSample and the last BwSample is greater than or equal to the threshold 
        percentage the LSP bandwidth is reported to PCE.</t> 
        <t>Stateful PCE will adjust the bandwidth of the LSP to the highest sampled 
        traffic rate amongst the set of samples taken over the adjustment-interval. 
        Note that the highest sampled traffic rate could be higher or lower than 
        the current LSP bandwidth. Only if the current MaxAvgBw  and the current 
        bandwidth allocation is greater than or equal to the Adjust-Threshold percentage 
        the LSP bandwidth is adjusted to the current bandwidth demand.</t>
        <t>Also to avoid multiple LSP re-signaling, sometimes operator set up longer 
        adjustment intervals. However long adjustment-interval can also result in 
        an undesirable effect of masking sudden changes in traffic patterns. To avoid 
        this, the stateful PCE MAY pre-maturely expire the adjustment-interval to 
        accommodate sudden bursts in traffic.</t>
      </section>
    </section>
    <section title="Extensions to the PCEP" toc="default">
        <section title="AUTO-BANDWIDTH-ATTRIBUTE TLV" toc="default">
        <t>The AUTO-BANDWIDTH-ATTRIBUTE TLV can be included as an optional TLV in the 
        LSP object as described in <xref target='I-D.ietf-pce-stateful-pce'/>. Whenever the LSP 
        with Auto-Bandwidth feature enabled is delegated, 
        AUTO-BANDWIDTH-ATTRIBUTE TLV is carried in PCRpt message. The TLV provides PCE with the
		'local configurable knobs' of this feature.	
        In case of PCE Initiated LSP  (<xref target='I-D.ietf-pce-pce-initiated-lsp'/>) 
        with this feature enabled, this TLV is included in LSP object with PCInitiate message.</t>
        <t>The format of the AUTO-BANDWIDTH-ATTRIBUTE TLV is shown in the following figure:</t>
        <figure title="AUTO-BANDWIDTH-ATTRIBUTE TLV format" suppress-title="false" align="left" alt="" width="" height="">
        <artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[
 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|           Type=[TBD]          |           Length=16           |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|  Sample Int   |    Adj Int    | Rpt Threshold | Adj Threshold |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                     Minimum Bandwidth                         |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                     Maximum Bandwidth                         |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|          Reserved             |           Flags             |L|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+   
   
    ]]></artwork>
      </figure>
      <t>The type of the TLV is [TBD] and it has a fixed length of 16 octets.</t>
      <t>The value contains the following fields:</t>
      <t>
        <list style="hanging">
		  <t hangText="Sample Int (8 bits):">The Sample-Interval, time interval 
		  in which the traffic rate is collected at the PCC.</t>
		  <t hangText="Adj Int (8 bits):">The Adjustment-Interval, time interval 
		  in which the bandwidth adjustment should be made.</t>
		  <t hangText="Rpt Threshold (8 bits):">The Report-Threshold value is 
          encoded in percentage. Only if the percentage difference between 
          the between the current BwSample and the last BwSample is greater 
		  than or equal to the threshold percentage the real time bandwidth sample is 
		  reported to PCE.</t>
		  <t hangText="Adj Threshold (8 bits):">The Adjust-Threshold value is 
          encoded in percentage. Only if the percentage difference between 
          the current MaxAvgBw  and the current bandwidth allocation is 
          greater than or equal to the threshold percentage the LSP 
          bandwidth is adjusted to the current bandwidth demand.</t>
          <t hangText="Minimum Bandwidth (32 bits):">The minimum bandwidth 
          allowed is encoded in IEEE floating point format (see 
          <xref target="IEEE.754.1985"/>), expressed in bytes per second.  
          Refer to Section 3.1.2 of <xref target="RFC3471"/> for a table of 
          commonly used values.</t>
          <t hangText="Maximum Bandwidth (32 bits):">The maximum bandwidth 
          allowed is encoded in IEEE floating point format (see 
          <xref target="IEEE.754.1985"/>), expressed in bytes per second.  
          Refer to Section 3.1.2 of <xref target="RFC3471"/> for a table of 
          commonly used values.</t>
          
          <t hangText="Flags (16 bits):">One flag is currently defined:
          <list style="symbols">
          <t>L (Live-Traffic - 1 bit): If set, PCC SHOULD report the 
          live traffic information flowing on the LSP as per the 
          Report-Threshold set. Otherwise PCC only reports the calculated
          bandwidth to be adjusted to the PCE.</t>
          </list>
          Unassigned flags MUST be set to zero on transmission and MUST be
          ignored on receipt.
          </t>
          <t hangText="Reserved (16 bits):">This field MUST be set to zero on transmission
      and MUST be ignored on receipt.</t>
        </list>
    </t> 
    <t>If the above parameters are not specified by the user, based 
    on the local policy at Ingress (PCC) the default value can be 
    encoded. </t>
    <t>If no default value is specified at Ingress, value 'zero' 
    can be encoded for the particular field. The stateful PCE can 
    then apply its own default value based on the local policy.</t>
    </section>
        <section title="BANDWIDTH Object" toc="default">
        <t>As per <xref target="RFC5440"/>, the BANDWIDTH object is 
        defined with two Object-Type values:</t>
        <t>
        <list style="symbols">
        <t>Requested Bandwidth: BANDWIDTH Object-Type is 1.</t>
        <t>Re-optimization Bandwidth: Bandwidth of an existing TE LSP 
        for which a reoptimization is requested.  BANDWIDTH Object-Type 
        is 2.</t>
        </list>
        </t>
        <t>The new BANDWIDTH object type 3 [TBD] is used to specify the 
        BwSample determined from the existing TE LSP Traffic flow at every 
        sample-interval when L bit is set in AUTO-BANDWIDTH-ATTRIBUTE TLV. 
        The Report-Threshold percentage is used to 
        determine if there is a need to report the current BwSample.</t>
        
        <t>If Live-Traffic (L-Bit) is not set, PCC only reports the calculated
          bandwidth to be adjusted (MaxAvgBw) to the PCE. This is done via the existing 
          'Requested Bandwidth with BANDWIDTH Object-Type as 1'.</t>
        </section>
        <section title="The PCRpt Message" toc="default">
        <t>When the delegated LSP is enabled with the Auto-Bandwidth 
        adjustment feature with Live-Traffic (L-Bit) set, PCC SHOULD include the BANDWIDTH object of type 
        3 [TBD] in the PCRpt message. The definition of the PCRpt message 
        (see <xref target='I-D.ietf-pce-stateful-pce'/>) is unchanged.</t>
        <t>When LSP is delegated to a PCE for the very first time, BANDWIDTH
         object of type 1 is used to specify the requested bandwidth in the 
         PCRpt message. To report the live traffic flow information (as the BwSample) 
         the BANDWIDTH object of type 3 [TBD] is encoded in further PCRpt message.</t>  
         
         <t>If Live-Traffic (L-Bit) is not set, PCC SHOULD include the BANDWIDTH object of type 
        1 to specify the he calculated
          bandwidth to be adjusted to the PCE.</t>
        </section>
        <section title="The PCInitiate Message" toc="default">
        <t>For PCE Initiated LSP  (<xref target='I-D.ietf-pce-pce-initiated-lsp'/>) 
        with Auto-Bandwidth feature enabled, AUTO-BANDWIDTH-ATTRIBUTE TLV is included 
        in LSP object with the PCInitiate message. The rest of the processing remains
        unchanged.</t>
        </section>
    </section>
    <section title="Security Considerations" toc="default">
      <t>This document defines a new BANDWIDTH type and AUTO-BANDWIDTH-ATTRIBUTE TLV which does not add any new 
      security concerns beyond those discussed in <xref target="RFC5440"/> 
      and <xref target='I-D.ietf-pce-stateful-pce'/> in itself. Some deployments may find the 
      live traffic bandwidth information  as extra sensitive 
      and thus should employ suitable PCEP security mechanisms like TCP-AO 
      or <xref target='I-D.ietf-pce-pceps'/>.</t>

    </section>
    <section title="Manageability Considerations" toc="default">
      <section title="Control of Function and Policy" toc="default">
        <t>The Auto-Bandwidth feature MUST BE controlled per tunnel at Ingress 
        (PCC), the values for parameters like sample-interval, adjustment-interval, 
        minimum-bandwidth, maximum-bandwidth, report-threshold, adjust-threshold, 
        Live-Traffic (L-Bit) SHOULD BE configurable by an operator.</t>
      </section>
      <section title="Information and Data Models" toc="default">
        <t><xref target="RFC7420"/> describes the PCEP MIB, there are no new MIB Objects 
        for this document.</t>
      </section>
      <section title="Liveness Detection and Monitoring" toc="default">
        <t>Mechanisms defined in this document do not imply any new liveness detection 
        and monitoring requirements in addition to those already listed in 
        <xref target="RFC5440"/>.</t>
      </section>
      <section title="Verify Correct Operations" toc="default">
        <t>Mechanisms defined in this document do not imply any new operation 
        verification requirements in addition to those already listed in 
        <xref target="RFC5440"/>.</t>
      </section>
      <section title="Requirements On Other Protocols" toc="default">
        <t>Mechanisms defined in this document do not imply any new requirements 
        on other protocols.</t>
      </section>
      <section title="Impact On Network Operations" toc="default">
        <t>Mechanisms defined in this document do not have any impact on 
        network operations in addition to those already listed in 
        <xref target="RFC5440"/>.</t>
      </section>
    </section>    
    <section title="IANA Considerations" toc="default">
    <section title="PCEP TLV Type Indicators" toc="default">
    <t>This document defines the following new PCEP TLVs; IANA is 
    requested to make the following allocations from this registry.</t>
      <t>
 <figure title="" suppress-title="false" align="left" alt="" width="" height="">
   <artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[
Value     Meaning                     Reference
TBD       AUTO-BANDWIDTH-ATTRIBUTE    [This I.D.]       
]]></artwork>
        </figure>
      </t>
    </section>
    <section title="AUTO-BANDWIDTH-ATTRIBUTE" toc="default">
    <t>This document requests that a registry is created to manage the Flags
   field in the AUTO-BANDWIDTH-ATTRIBUTE TLV in the LSP object.  New
   values are to be assigned by Standards Action <xref target="RFC5226"/>.  Each bit
   should be tracked with the following qualities:
   <list style="symbols"> 
   <t>Bit number (counting from bit 0 as the most significant bit)</t>
   <t>Capability description</t>
   <t>Defining RFC</t>
    </list>
    </t>
   <t>The following values are defined in this document:</t>
      <t>
 <figure title="" suppress-title="false" align="left" alt="" width="" height="">
   <artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[
Bit     Description            Reference
31      Live-Traffic (L-Bit)   [This I.D.]

]]></artwork>
        </figure>
      </t>   
    </section>
    <section title="BANDWIDTH Object" toc="default">      
    <t>This document defines new object type for the BANDWIDTH object; 
    IANA is requested to make the following allocations from this registry.</t>
      <t>
    <figure title="" suppress-title="false" align="left" alt="" width="" height="">
      <artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[
Object-Class Value   Name                               Reference
     5             BANDWIDTH                            [This I.D.]
                    Object-Type
                      3: MaxAvgBw determined from 
                      the existing TE LSP Traffic 
                      flow.
]]></artwork>
        </figure>
      </t>
    </section>
    </section>
    
    <section title="Acknowledgments" toc="default">
      <t>We would like to thank Venugopal Reddy, Reeja Paul, Sandeep Boina 
      and Avantika for their useful comments and suggestions.</t>
    </section>    
  </middle>
  <back>
    <references title="Normative References">
    <?rfc include="reference.RFC.2119.xml" ?>
    <?rfc include="reference.RFC.5440.xml" ?>
    <?rfc include="reference.I-D.ietf-pce-stateful-pce"?>
    <?rfc include="reference.I-D.ietf-pce-pce-initiated-lsp"?>
    
    </references>
    <references title="Informative References">
      <?rfc include="reference.RFC.3471.xml" ?>
      <?rfc include="reference.RFC.5226.xml" ?>
      <?rfc include="reference.RFC.7420.xml" ?>
      <?rfc include="reference.I-D.ietf-pce-stateful-pce-app"?>
      <?rfc include="reference.I-D.ietf-pce-pceps"?>
      <!--IEEE.754.1985-->
      <reference anchor="IEEE.754.1985">
      <front>
       <title>Standard for Binary Floating-Point Arithmetic</title>
        <author>
         <organization>Institute of Electrical and Electronics Engineers</organization>
         </author>
        <date month="August" year="1985"/>
        </front>
       <seriesInfo name="IEEE" value="Standard 754"/>
      </reference> 
      
     
            
    </references>
<section title="Contributor Addresses" toc="default">
    <t>
    <figure title="" suppress-title="false" align="left" alt="" width="" height="">
          <artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[
He Zekun
Tencent Holdings Ltd,
Shenzhen P.R.China       
   
Email: kinghe@tencent.com
          
Xian Zhang
Huawei Technologies 
Research Area F3-1B, 
Huawei Industrial Base, 
Shenzhen, 518129, China 
    
Phone: +86-755-28972645 
Email: zhang.xian@huawei.com
 
Young Lee
Huawei Technologies
1700 Alma Drive, Suite 100
Plano, TX  75075
US
 
Phone: +1 972 509 5599 x2240
Fax:   +1 469 229 5397
EMail: leeyoung@huawei.com
        ]]></artwork>
        </figure>
      </t>
    </section>    
  </back>
</rfc>

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