 module ietf-network-topology {
   yang-version 1;
   namespace "urn:ietf:params:xml:ns:yang:ietf-network-topology";
   prefix lnk;

   import ietf-inet-types {
     prefix inet;
   }
   
   typedef tp-id {
     type inet:uri;
     description
       "An identifier for termination points on a node.
        The identifier SHOULD be chosen such that the same TP 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 TP and/or the type of node and topology that the TP is a
        part of.";
   }

   grouping tp-ref {
     description
       "References a termination point in a specific node.";
     leaf tp-ref {
       type tp-id;
       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.)";
     }
   }
 }