draft-dhody-pce-pcep-srv6-yang-00.xml

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<rfc ipr="trust200902" category="std" docName="draft-dhody-pce-pcep-srv6-yang-00" obsoletes="" updates="" submissionType="IETF" xml:lang="en">
  <front>
    <title abbrev="PCE-YANG">A YANG Data Model for Segment Routing in IPv6 (SRv6) support in Path Computation Element Communications Protocol (PCEP)</title>

    <author initials="D" surname="Dhody" fullname="Dhruv Dhody" role="editor">
      <organization>Huawei Technologies</organization>
      <address>
        <postal>
          <street>Divyashree Techno Park, Whitefield</street>
          <city>Bangalore</city>
          <region>Karnataka</region>
          <code>560066</code>
          <country>India</country>
        </postal>
        <email>dhruv.ietf@gmail.com</email>
      </address>
    </author>

    <author fullname="Siva Sivabalan" initials="S." surname="Sivabalan">
      <organization>Cisco Systems, Inc.</organization>
      <address>
        <postal>
          <street>2000 Innovation Drive</street>
          <city>Kanata</city>
          <region>Ontario</region>
          <code>K2K 3E8</code>
          <country>Canada</country>
        </postal>
        <email>msiva@cisco.com</email>
      </address>
    </author>

    <date year="2018" />
    <area>Routing</area>
    <workgroup>PCE Working Group</workgroup>
    <abstract>
    <t>This document augments a YANG data model for the management of
    Path Computation Element communications Protocol (PCEP) for
    communications between a Path Computation Client (PCC) and a Path
    Computation Element (PCE), or between two PCEs in support for Segment Routing in IPv6. The data model
    includes configuration data and state data (status information and
    counters for the collection of statistics).</t>
    </abstract>
  </front>
  <middle>
    <section title="Introduction" toc="default">
    <t>The Path Computation Element (PCE) defined in <xref target="RFC4655"/>
    is an entity that is capable of computing a network path or route
    based on a network graph, and applying computational constraints.
    A Path Computation Client (PCC) may make requests to a PCE for paths
    to be computed.</t>

   <t>PCEP is the communication protocol between a PCC and PCE and is
   defined in <xref target="RFC5440"/>. PCEP interactions include path
   computation requests and path computation replies as well as
   notifications of specific states related to the use of a PCE in the
   context of Multiprotocol Label Switching (MPLS) and Generalized MPLS
   (GMPLS) Traffic Engineering (TE). <xref target='RFC8231'/>
   specifies extensions to PCEP to enable stateful control of MPLS TE LSPs. </t>

   <t>
    <xref target="I-D.negi-pce-segment-routing-ipv6"/> extends
   <xref target="I-D.ietf-pce-segment-routing"/> to support SR for IPv6 data plane.</t>

   <t><xref target="I-D.ietf-pce-pcep-yang"/> defines a YANG <xref target="RFC7950"/> data model
   for the management of PCEP speakers. This document contains a specification of the PCEP-SRv6 YANG module,
   "ietf-pcep-srv6" which provides the PCEP-SRv6 <xref target="I-D.negi-pce-segment-routing-ipv6"/> data
   model.</t>

   <t>The PCEP operational state is included in the same tree as the PCEP
    configuration consistent with Network Management Datastore
   Architecture <xref target="RFC8342"/>. 
   The origin of the data is indicated as per the origin metadata 
   annotation.</t>

    </section>
<section title="Requirements Language" toc="default">
        <t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
      NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED",
      "MAY", and "OPTIONAL" in this document are to be interpreted as
      described in BCP 14 <xref target="RFC2119" /> <xref target="RFC8174"/> when, and only when, they
      appear in all capitals, as shown here.</t>
      </section>
    <section title="Terminology and Notation" toc="default">

        <t>
          This document also uses the following terms defined in
          <xref target="RFC7420"/>:
          <list style='symbols'>
            <t>
            PCEP entity: a local PCEP speaker.
            </t>
            <t>
            PCEP peer: to refer to a remote PCEP speaker.
            </t>
            <t>PCEP speaker: where it is not necessary to distinguish between local
          and remote.
        </t>
        </list>
        </t>
      <t>
          Further, this document also uses the following terms defined in
          <xref target='RFC8231'/> :
          <list style='symbols'>
            <t>
            Stateful PCE, Passive Stateful PCE, Active Stateful PCE
            </t>
            <t>
            Delegation, Revocation, Redelegation
            </t>
            <t>LSP State Report, Path Computation Report message (PCRpt).</t>
            <t>LSP State Update, Path Computation Update message (PCUpd).</t>
        </list>
        </t>
      <t>
          <xref target='RFC8281'/> :
          <list style='symbols'>
            <t>PCE-initiated LSP, Path Computation LSP Initiate Message (PCInitiate).</t>
        </list>
        </t>
      <t>
          <xref target='RFC8408'/> :
          <list style='symbols'>
            <t>Path Setup Type (PST).</t>
        </list>
        </t>

      <t>
          <xref target='I-D.ietf-pce-segment-routing'/> :
          <list style='symbols'>
            <t>Segment Routing (SR).</t>


        </list>
        </t>
      <t>
          <xref target='I-D.negi-pce-segment-routing-ipv6'/> :
          <list style='symbols'>
            <t>Segment Routing in IPv6 (SRv6).</t>


        </list>
        </t>

    <section anchor="sec.tree-symbols" title="Tree Diagrams" toc="default">
      <t>A simplified graphical representation of the data model is used in this
       document. The meaning of the symbols in these diagrams is defined in <xref target="RFC8340"/>. 
      </t>
      <!--
      <list style="symbols">
        <t>Brackets "[" and "]" enclose list keys.</t>
        <t>Abbreviations before data node names: "rw" means
        configuration (read-write) and "ro" state data
        (read-only).</t>
        <t>Symbols after data node names: "?" means an optional node, "!"
      means a presence container, and "*" denotes a list and leaf-list.</t>


        <t>Parentheses enclose choice and case nodes, and case nodes
        are also marked with a colon (":").</t>
        <t>Ellipsis ("...") stands for contents of subtrees that are
        not shown.</t>
      </list></t>-->
    </section>
    <section title="Prefixes in Data Node Names" toc="default">
      <t>In this document, names of data nodes and other data
   model objects are often used without a prefix, as long as it is clear
   from the context in which YANG module each name is defined.
   Otherwise, names are prefixed using the standard prefix associated
   with the corresponding YANG module, as shown in <xref target="tab.prefixes" pageno="false" format="default"/>.</t>

      <texttable anchor="tab.prefixes" title="Prefixes and corresponding YANG modules" suppress-title="false" align="center" style="full">
        <ttcol align="left">Prefix</ttcol>
        <ttcol align="left">YANG module</ttcol>
        <ttcol align="left">Reference</ttcol>
        <c>te-types</c><c>ietf-te-types</c><c><xref target="I-D.ietf-teas-yang-te" pageno="false" format="default"/></c>
        <c>p</c><c>ietf-pcep</c><c><xref target="I-D.ietf-pce-pcep-yang" pageno="false" format="default"/></c>
        <c>st</c><c>ietf-srv6-types</c><c><xref target="I-D.raza-spring-srv6-yang" pageno="false" format="default"/></c>
      </texttable>
    </section>
    </section>

    <section title="The Design of PCEP-SRv6 Data Model" toc="default" anchor="sec.data-tree">
<section title="The Overview of PCEP SRv6 Data Model" toc="default" anchor="sec.overview.data-tree">
<t>The PCEP-SRv6 YANG module defined in this document has all the common
   building blocks for the PCEP-SRv6 extention.
<figure title="" suppress-title="false" align="left" alt="" width="" height="">
          <artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[
module: ietf-pcep-srv6
  augment /p:pcep/p:entity/p:capability:
    +--rw srv6 {srv6}?
       +--rw enabled?    boolean
       +--rw max-sl?     uint8
       +--rw sl-limit?   boolean
  augment /p:pcep/p:entity/p:peers/p:peer/p:capability:
    +--rw srv6 {srv6}?
       +--rw enabled?    boolean
       +--rw max-sl?     uint8
       +--rw sl-limit?   boolean
  augment /p:pcep/p:entity/p:lsp-db/p:lsp:
    +--ro srv6 {srv6}?
       +--ro segment-list
          +--ro segment* [index]
             +--ro index        uint32
             +--ro sid-value?   st:srv6-sid
  groupings:
  segment-list
      +---- segment-list
         +---- segment* [index]
            +---- index?       uint32
            +---- sid-value?   st:srv6-sid

  segment-properties
      +---- index?       uint32
      +---- sid-value?   st:srv6-sid

  srv6
      +---- srv6 {srv6}?
         +---- enabled?    boolean
         +---- max-sl?     uint8
         +---- sl-limit?   boolean

                  ]]></artwork>
        </figure>
      </t>
</section>


    </section>

   




    <section title="PCEP-SRv6 YANG Modules" toc="default">
      <section title="ietf-pcep-srv6 module" toc="default">
    <t>RFC Ed.: In this section, replace all occurrences of 'XXXX' with the
   actual RFC number and all occurrences of the revision date below with
   the date of RFC publication (and remove this note).</t>
    <figure title="" suppress-title="false" align="left" alt="" width="" height="">
          <artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height="">
          <![CDATA[
<CODE BEGINS> file "ietf-pcep-srv6@2018-10-19.yang"
module ietf-pcep-srv6 {

    yang-version 1.1;

    namespace "urn:ietf:params:xml:ns:yang:ietf-pcep-srv6";
    prefix ps;


    import ietf-srv6-types {
        prefix "st";
        reference "RFC XXXX";
    }

    import ietf-te-types {
       prefix "te-types";
       reference "RFC XXXX";
    }

    import ietf-pcep {
       prefix "p";
       reference "RFC XXXX";
    }


    organization
        "IETF PCE (Path Computation Element) Working Group";

    contact
        "WG Web:   <http://tools.ietf.org/wg/pce/>
         WG List:  <mailto:pce@ietf.org>
         Editor:   Dhruv Dhody
                   <mailto:dhruv.ietf@gmail.com>";
    description
        "The YANG module augments the PCEP yang operational
        model with SRv6";


    revision 2018-10-19 {
        description "Initial revision.";
        reference
            "RFC XXXX:  A YANG Data Model for Path Computation
                        Element Communications Protocol
                        (PCEP) - Segement Routing in IPv6
                        (SRv6)";
    }

    /* Identity */
    identity path-setup-srv6 {
        base te-types:path-signaling-type;
        description
          "SRv6 path setup type";
    }
    
    /* Features */
    feature srv6 {
        description
            "Support Segment Routing in IPv6 (SRv6) for PCE.";
    }

    /* Groupings */
    grouping srv6 {
        description
            "SRv6";
        container srv6 {
            if-feature srv6;
            description
                "If SRv6 is supported";
            leaf enabled{
                type boolean;
                description
                    "Enabled or Disabled";
            }
            leaf max-sl {
                type uint8;
                description
                    "Max value of the segment left field in SRH";
            }
            leaf sl-limit{
                type boolean;
                default false;
                description
                    "True indicates no limit on SL, the
                    leaf max-sl is ignored";
            }
        }
    }

    grouping segment-list {
        description
            "Segment list grouping";
        container segment-list {
            description
                "Segments for given segment list";

            list segment {
                key "index";
                description "Configure Segment/hop at the index";
                uses segment-properties;
            }
        }
    }

    grouping segment-properties {
        description "Segment properties grouping";
        leaf index {
            type uint32;
            description "Segment index";
        }
        leaf sid-value {
            type st:srv6-sid;
            description "SRv6 SID value";
        }
    }


    /*
     * Augment modules to add SRv6
     */
    augment "/p:pcep/p:entity/p:capability"{
        description
            "Augmenting SRv6";
        uses srv6;
    }
    augment "/p:pcep/p:entity/p:peers/p:peer/p:capability"{
        description
            "Augmenting SRv6";
        uses srv6;
    }
    augment "/p:pcep/p:entity/p:lsp-db/p:lsp"{
        description
            "Augmenting SRv6";
        container srv6 {
            when "/p:pcep/p:entity/p:lsp-db/p:lsp/p:pst 
                  = 'path-setup-srv6'" {
                description
                    "For SRv6 path";
            }
            if-feature srv6;
            uses segment-list;
            description
                "SRv6";
        }
    }
    
}//module

<CODE ENDS>
                     ]]></artwork>
        </figure>
</section>

  </section>



    <section title="Security Considerations" toc="default">
      <t>The YANG module defined in this document is designed to be accessed via
   network management protocol such as NETCONF <xref target="RFC6241"/>
   or RESTCONF <xref target="RFC8040"/>.  The lowest NETCONF layer is the secure
   transport layer and the mandatory-to-implement secure transport is
   SSH <xref target="RFC6242"/>. The lowest RESTCONF layer is HTTPS, and the
   mandatory-to-implement secure transport is TLS <xref target="RFC8446"/></t>

        <t>The NETCONF access control model <xref target="RFC8341"/> provides
   the means to restrict access for particular NETCONF or RESTCONF users to a
   pre-configured subset of all available NETCONF or RESTCONF protocol
   operations and content.</t>

        <t>There are a number of data nodes defined in the YANG module which are
   writable/creatable/deletable (i.e., config true, which is the
   default).  These data nodes may be considered sensitive or vulnerable
   in some network environments.  Write operations (e.g.,  &lt;edit-config&gt;)
   to these data nodes without proper protection can have a negative
   effect on network operations. These are the subtrees and data nodes and 
   their sensitivity/vulnerability:
   <list>
   <t>/p:pcep/p:entity/p:capability/ps:srv6 - configure local SRv6 capability and parameters.</t>
   <t>/p:pcep/p:entity/p:peers/p:peer/p:capability/ps:srv6 - configure peer's SRv6 capability and parameters.</t>
   </list></t>

   <t>Unauthorized access to above list can adversely affect the
   PCEP session between the local entity and the peers.  This may
   lead to inability to compute new paths, stateful operations on 
   the delegated as well as PCE-initiated LSPs.</t>

   <t>Some of the readable data nodes in this YANG module may be considered 
    sensitive or vulnerable in some network environments. It is thus important 
    to control read access (e.g., via get, get-config, or notification) to 
    these data nodes. These are the subtrees and data nodes and their 
    sensitivity/vulnerability:

   <list>
    <t>/p:pcep/p:entity/p:lsp-db/p:lsp/ps:srv6 - The SRv6 SID in the network. Unauthorized access to
      this could provide the all path and network usage information.</t>
  </list></t>

  <!--<t>Some of the RPC operations in this YANG module may be considered sensitive 
    or vulnerable in some network environments. It is thus important to control
    access to these operations. These are the operations and their 
    sensitivity/vulnerability:
    <list>

  <t>trigger-resync - trigger resynchronization with the PCE. Unauthorized access to 
      this could force a PCEP session into continuous state synchronization. </t>
  </list></t>-->

    </section>

    
    <section title="IANA Considerations" toc="default">
    <t>This document registers a URI in the "IETF XML Registry"
    <xref target="RFC3688"/>.
   Following the format in RFC 3688, the following registration has been
   made.
   <list style="hanging">

       <t hangText="URI:">urn:ietf:params:xml:ns:yang:ietf-pcep-srv6</t>

       <t hangText="Registrant Contact:">The PCE WG of the IETF.</t>

       <t hangText="XML:">N/A; the requested URI is an XML namespace.</t>
       </list>
   </t>
   <t>This document registers a YANG module in the "YANG Module Names"
   registry <xref target="RFC6020"/>.
    <figure title="" suppress-title="false" align="left" alt="" width="" height="">
          <artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[
    Name:         ietf-pcep
    Namespace:    urn:ietf:params:xml:ns:yang:ietf-pcep-srv6
    Prefix:       ps
    Reference:    This I-D
        ]]></artwork>
        </figure>
    </t>
    </section>

    <section title="Acknowledgements" toc="default">
    </section>
  </middle>
  <back>
    <references title="Normative References">
    <?rfc include="reference.RFC.2119.xml" ?>
    <?rfc include="reference.RFC.3688.xml" ?>
    <?rfc include="reference.RFC.5440.xml" ?>
    
    <?rfc include="reference.RFC.6020.xml" ?>
    <?rfc include="reference.RFC.6241.xml" ?>
    <?rfc include="reference.RFC.6242.xml" ?>
    
    <?rfc include="reference.RFC.7950.xml" ?>
    <?rfc include="reference.RFC.8040.xml" ?>
    <?rfc include="reference.RFC.8174.xml"?>
    <?rfc include="reference.RFC.8231.xml"?>
    <?rfc include="reference.RFC.8281.xml"?>
    <?rfc include="reference.RFC.8340.xml"?>
    <?rfc include="reference.RFC.8341.xml" ?>
    <?rfc include="reference.RFC.8408.xml" ?>
    <?rfc include="reference.RFC.8446.xml" ?>
    
    <?rfc include="reference.I-D.ietf-teas-yang-te"?>
    <?rfc include="reference.I-D.ietf-pce-segment-routing"?>
    <?rfc include="reference.I-D.raza-spring-srv6-yang"?>
    <?rfc include="reference.I-D.ietf-pce-pcep-yang"?>
    <?rfc include="reference.I-D.negi-pce-segment-routing-ipv6"?>

    </references>
    <references title="Informative References">
      <?rfc include="reference.RFC.4655.xml" ?>
      <?rfc include="reference.RFC.7420.xml" ?>      
      <?rfc include="reference.RFC.8342.xml"?>

          
      
      

    </references>



  </back>
</rfc>