diff --git a/models/yang/instantiation-parameters.yang b/models/yang/instantiation-parameters.yang
index 810b959..dbf38b7 100644
--- a/models/yang/instantiation-parameters.yang
+++ b/models/yang/instantiation-parameters.yang
@@ -10,10 +10,6 @@
   namespace "urn:ietf:params:xml:ns:yang:nfvo:instantiation-parameters";
   prefix "instantiation-parameters";
   
-  import rw-project {
-    prefix "rw-project";
-  }
-  
   import nsd {
     prefix "nsd";
   }
@@ -22,10 +18,6 @@
     prefix "vnfd";
   }
 
-  import nsr {
-    prefix "nsr";
-  }
-
   import ietf-inet-types {
     prefix "inet";
   }
@@ -39,20 +31,7 @@
     description "Initial version";
   }
 
-  grouping ns_instantiate {
-    leaf nsName {
-      mandatory true;
-      type string;
-    }
-    leaf nsDescription {
-      type string;
-    }
-    leaf nsdId {
-      mandatory true;
-      type leafref {
-        path "/nsd:nsd-catalog/nsd:nsd/nsd:id";
-      }
-    }
+  grouping netslice_params {
     leaf vimAccountId {
       mandatory true;
       type string;
@@ -60,23 +39,43 @@
     leaf ssh_keys {
       type string;
     }
-    leaf nsr_id {
-      config false;
-      type leafref {
-        path "/rw-project:project/nsr:ns-instance-opdata/nsr:nsr/nsr:ns-instance-config-ref";
-      }
+    list netslice-subnet {
+      key "id";
+      uses netslice_subnet_params;
     }
-    list vnf {
-      key "member-vnf-index";
-      uses vnf;
-    }
-    list vld {
+    list netslice-vld {
       key "name";
-      uses vld;
+      uses vld_params;
     }
   }
 
-  grouping vnf {
+  grouping netslice_subnet_params {
+    leaf id {
+      mandatory true;
+      type string;
+    }
+    uses ns_params;
+  }
+
+  grouping ns_params {
+    leaf vimAccountId {
+      mandatory true;
+      type string;
+    }
+    leaf ssh_keys {
+      type string;
+    }
+    list vnf {
+      key "member-vnf-index";
+      uses vnf_params;
+    }
+    list vld {
+      key "name";
+      uses vld_params;
+    }
+  }
+
+  grouping vnf_params {
     leaf member-vnf-index{
       mandatory true;
       type string;
@@ -86,15 +85,15 @@
     }
     list vdu {
       key "id";
-      uses ns_instantiate_vdu;
+      uses vdu_params;
     }
     list internal-vld {
       key "name";
-      uses ns-instantiate-internal-vld;
+      uses internal_vld_params;
     }
   }
 
-  grouping vld {
+  grouping vld_params {
     leaf name {
       type string;
     }
@@ -123,7 +122,7 @@
     }
   }
 
-  grouping ns_instantiate_vdu {
+  grouping vdu_params {
     leaf id {
       mandatory true;
       type string;
@@ -157,7 +156,7 @@
     }
   }
 
-  grouping ns-instantiate-internal-vld {
+  grouping internal_vld_params {
     leaf name {
       mandatory true;
       type string;
@@ -210,4 +209,4 @@
     }
   }
 
-}
\ No newline at end of file
+}
diff --git a/models/yang/nsi.yang b/models/yang/nsi.yang
index 32087d3..b6184e1 100644
--- a/models/yang/nsi.yang
+++ b/models/yang/nsi.yang
@@ -30,6 +30,10 @@
     prefix "instantiation-parameters";
   }
 
+  import ietf-yang-types {
+    prefix "yang";
+  }
+
   //revision history
   revision 2018-09-28 {
     description "Initial version";
@@ -37,23 +41,35 @@
 
   grouping nsi {
     leaf id {
+      description "Identifier for the NSI.";
+      type yang:uuid;
+    }
+
+    leaf name {
+      description "NSI name.";
+      type string;
+      mandatory true;
+    }
+
+    leaf short-name {
+      description "NSI short name.";
       type string;
     }
+
+    leaf description {
+      description "NSI description.";
+      type string;
+    }
+
     leaf nst-ref {
       type leafref {
         path "/nst:nst/nst:id";
       }
+      mandatory true;
     }
 
     container instantiation-parameters {
-      list netslice-subnet {
-        key "nsdId";
-        uses instantiation-parameters:ns_instantiate;
-      }
-      list netslice-vld {
-        key "name";
-        uses instantiation-parameters:vld;
-      }
+      uses instantiation-parameters:netslice_params;
     }
 
     container network-slice-template {
@@ -87,6 +103,7 @@
 
   list nsi{
     key "id";
+    unique "name";
     uses nsi;
   }
 
diff --git a/models/yang/nst.yang b/models/yang/nst.yang
index b501dae..85e2917 100644
--- a/models/yang/nst.yang
+++ b/models/yang/nst.yang
@@ -140,41 +140,20 @@
 
   grouping netslice-subnet {
     leaf id {
-      description "Identifier for the netslice-subnet.";
+      description "Identifier or name for the netslice-subnet in NST scope.";
       mandatory true;
       type string {
         length 1..63;
       }
     }
-    leaf name {
-      description "netslice-subnet name.";
-      mandatory true;
-      type string;
-    }
-    leaf short-name {
-      description "Short name to appear as label in the UI";
-      mandatory true;
-      type string;
-    }
-    leaf vendor {
-      description "Vendor of the NSD.";
-      mandatory true;
+    leaf description {
+      description "Description of the NSD.";
       type string;
     }
     leaf is-shared-nss {
       description "NSS is shared between NS";
-      mandatory true;
       type boolean;
-    }
-    leaf description {
-      description "Description of the NSD.";
-      mandatory true;
-      type string;
-    }
-    leaf version {
-      description "Version of the NSD";
-      mandatory true;
-      type string;
+      default false;
     }
     leaf nsd-ref {
       description "Reference to catalog NSD";
@@ -184,7 +163,7 @@
       }
     }
     container instantiation-parameters {
-      uses instantiation-parameters:ns_instantiate;
+      uses instantiation-parameters:ns_params;
     }
 
   }
@@ -297,6 +276,7 @@
 
     leaf name {
       type string;
+      mandatory true;
     }
 
     container SNSSAI-identifier {
@@ -317,7 +297,7 @@
       key "id";
       uses nsvld;
     }
-    list netslicefgd{
+    list netslicefgd {
       key "id";
       uses netslicefgd;
     }