ietf-network-topology.yang

module ietf-network-topology {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-network-topology";
  prefix lnk;

  import ietf-inet-types {
    prefix inet;
  }
  import ietf-network {
    prefix nd;
  }

  organization 
    "IETF I2RS (Interface to the Routing System) Working Group";
    
  contact
    "WG Web:    <http://tools.ietf.org/wg/i2rs/>
     WG List:   <mailto:i2rs@ietf.org>
     
     WG Chair:  Susan Hares
                <mailto:shares@ndzh.com>
                
     WG Chair:  Russ White
                <mailto:russ@riw.us>
     
     Editor:    Alexander Clemm
                <mailto:ludwig@clemm.org>
                
     Editor:    Jan Medved
                <mailto:jmedved@cisco.com>
                
     Editor:    Robert Varga
                <mailto:robert.varga@pantheon.sk>
                
     Editor:    Nitin Bahadur
                <mailto:nitin_bahadur@yahoo.com>
                
     Editor:    Hariharan Ananthakrishnan
                <mailto:hari@packetdesign.com>
                
     Editor:    Xufeng Liu
                <mailto:Xufeng_Liu@jabil.com>";
     
  description
    "This module defines a common base model for network topology, 
     augmenting the base network model with links to connect nodes, 
     as well as termination points to terminate links on nodes.
     
     Copyright (c) 2017 IETF Trust and the persons identified as
     authors of the code.  All rights reserved.

     Redistribution and use in source and binary forms, with or
     without modification, is permitted pursuant to, and subject
     to the license terms contained in, the Simplified BSD License
     set forth in Section 4.c of the IETF Trust's Legal Provisions
     Relating to IETF Documents 
     (http://trustee.ietf.org/license-info).

     This version of this YANG module is part of 
     draft-ietf-i2rs-yang-network-topo-12; 
     see the RFC itself for full legal notices.
     
     NOTE TO RFC EDITOR: Please replace above reference to 
     draft-ietf-i2rs-yang-network-topo-12 with RFC 
     number when published (i.e. RFC xxxx).";

  revision 2017-03-01 {
    description
      "Initial revision.
       NOTE TO RFC EDITOR: Please replace the following reference 
       to draft-ietf-i2rs-yang-network-topo-12 with 
       RFC number when published (i.e. RFC xxxx).";
    reference 
      "draft-ietf-i2rs-yang-network-topo-12";
  }

  typedef link-id {
    type inet:uri;
    description
      "An identifier for a link in a topology. 
       The precise structure of the link-id 
       will be up to the implementation.  
       The identifier SHOULD be chosen such that the same link in a
       real network topology will always be identified through the
       same identifier, even if the model is instantiated in 
	   separate datastores. An implementation MAY choose to capture
       semantics in the identifier, for example to indicate the type
       of link and/or the type of topology that the link is a part 
       of.";
  }

  typedef tp-id {
    type inet:uri;
    description
      "An identifier for termination points (TPs) on a node.
       The precise structure of the tp-id 
       will be up to the implementation.  
       The identifier SHOULD be chosen such that the same termination
       point in a real network topology will always be identified 
       through the same identifier, even if the model is instantiated 
       in separate datastores. An implementation MAY choose to 
       capture semantics in the identifier, for example to indicate 
       the type of termination point and/or the type of node 
       that contains the termination point."; 
  }

  grouping link-ref {
    description
      "References a link in a specific network.";
    leaf link-ref {
      type leafref {
        path "/nd:networks/nd:network[nd:network-id=current()/../"+
          "network-ref]/lnk:link/lnk:link-id";
        require-instance false;
      }
      description
        "A type for an absolute reference a link instance.
         (This type should not be used for relative references.
         In such a case, a relative path should be used instead.)";
    }
    uses nd:network-ref;
  }

  grouping tp-ref {
    description
      "References a termination point in a specific node.";
    leaf tp-ref {
      type leafref {
        path "/nd:networks/nd:network[nd:network-id=current()/../"+
          "network-ref]/nd:node[nd:node-id=current()/../"+
          "node-ref]/lnk:termination-point/lnk:tp-id";
        require-instance false;
      }
      description
        "A type for an absolute reference to a termination point.
         (This type should not be used for relative references.
         In such a case, a relative path should be used instead.)";
    }
    uses nd:node-ref;
  }

  augment "/nd:networks/nd:network" {
    description 
      "Add links to the network model.";
    list link {
      key "link-id";
      description
        "A network link connects a local (source) node and
         a remote (destination) node via a set of 
         the respective node's termination points.
         It is possible to have several links between the same
         source and destination nodes.  Likewise, a link could
         potentially be re-homed between termination points.
         Therefore, in order to ensure that we would always know 
         to distinguish between links, every link is identified by 
         a dedicated link identifier.  Note that a link models a 
         point-to-point link, not a multipoint link.";
      container source {
        description
          "This container holds the logical source of a particular
           link.";
        leaf source-node {
          type leafref {
            path "../../../nd:node/nd:node-id";
            require-instance false;
          }
          description
            "Source node identifier, must be in same topology.";
        }
        leaf source-tp {
          type leafref {
            path "../../../nd:node[nd:node-id=current()/../"+
              "source-node]/termination-point/tp-id";
            require-instance false;
          }
          description
            "Termination point within source node that terminates
             the link.";
        }
      }
      container destination {
        description
          "This container holds the logical destination of a
           particular link.";
        leaf dest-node {
          type leafref {
            path "../../../nd:node/nd:node-id";
          require-instance false;
          }
          description
            "Destination node identifier, must be in the same
             network.";
        }
        leaf dest-tp {
          type leafref {
            path "../../../nd:node[nd:node-id=current()/../"+
              "dest-node]/termination-point/tp-id";
            require-instance false;
          }
          description
            "Termination point within destination node that
             terminates the link.";
        }
      }
      leaf link-id {
        type link-id;
        description
          "The identifier of a link in the topology.
           A link is specific to a topology to which it belongs.";
      }
      list supporting-link {
        key "network-ref link-ref";
        description
          "Identifies the link, or links, that this link
           is dependent on.";
        leaf network-ref {
          type leafref {
            path "../../../nd:supporting-network/nd:network-ref";
          require-instance false;
          }
          description
            "This leaf identifies in which underlay topology
             the supporting link is present.";
        }
        leaf link-ref {
          type leafref {
            path "/nd:networks/nd:network[nd:network-id=current()/"+
              "../network-ref]/link/link-id";
            require-instance false;
          }
          description
            "This leaf identifies a link which is a part
             of this link's underlay. Reference loops in which
             a link identifies itself as its underlay, either
             directly or transitively, are not allowed.";
        }
      }
    }
  }
  augment "/nd:networks/nd:network/nd:node" {
    description
      "Augment termination points which terminate links.  
       Termination points can ultimately be mapped to interfaces.";
    list termination-point {
      key "tp-id";
      description
        "A termination point can terminate a link.
         Depending on the type of topology, a termination point
         could, for example, refer to a port or an interface.";
      leaf tp-id {
        type tp-id;
        description
          "Termination point identifier.";
      }
      list supporting-termination-point {
        key "network-ref node-ref tp-ref";
        description
          "This list identifies any termination points that
           the termination point is dependent on, or maps onto.
           Those termination points will themselves be contained
           in a supporting node.
           This dependency information can be inferred from
           the dependencies between links.  For this reason,
           this item is not separately configurable.  Hence no
           corresponding constraint needs to be articulated.
           The corresponding information is simply provided by the
           implementing system.";
        leaf network-ref {
          type leafref {
            path "../../../nd:supporting-node/nd:network-ref";
          require-instance false;
          }
          description
            "This leaf identifies in which topology the
             supporting termination point is present.";
        }
        leaf node-ref {
          type leafref {
            path "../../../nd:supporting-node/nd:node-ref";
          require-instance false;
          }
          description
            "This leaf identifies in which node the supporting
             termination point is present.";
        }
        leaf tp-ref {
          type leafref {
            path "/nd:networks/nd:network[nd:network-id=current()/"+
              "../network-ref]/nd:node[nd:node-id=current()/../"+
              "node-ref]/termination-point/tp-id";
            require-instance false;
          }
          description
            "Reference to the underlay node, must be in a
             different topology";
        }
      }
    }
  }
}