diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/datamodel/YangEnum.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/datamodel/YangEnum.java
index a9f80e3..df702e9 100644
--- a/utils/yangutils/src/main/java/org/onosproject/yangutils/datamodel/YangEnum.java
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/datamodel/YangEnum.java
@@ -50,7 +50,7 @@
 /**
  * Represents the ENUM data type information.
  */
-public class YangEnum implements YangCommonInfo, Parsable {
+public class YangEnum implements YangCommonInfo, Parsable, Comparable<YangEnum> {
 
     /**
      * Named value for the ENUM.
@@ -226,4 +226,12 @@
     public void validateDataOnExit() throws DataModelException {
         // TODO auto-generated method stub, to be implemented by parser
     }
+
+    @Override
+    public int compareTo(YangEnum otherEnum) {
+        if (this.namedValue.equals(otherEnum.getNamedValue())) {
+            return 0;
+        }
+        return new Integer(this.value).compareTo(otherEnum.getValue());
+    }
 }
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/datamodel/YangEnumeration.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/datamodel/YangEnumeration.java
index 65f733c..9bf924a 100644
--- a/utils/yangutils/src/main/java/org/onosproject/yangutils/datamodel/YangEnumeration.java
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/datamodel/YangEnumeration.java
@@ -16,8 +16,8 @@
 
 package org.onosproject.yangutils.datamodel;
 
-import java.util.HashSet;
-import java.util.Set;
+import java.util.SortedSet;
+import java.util.TreeSet;
 
 import org.onosproject.yangutils.datamodel.exceptions.DataModelException;
 import org.onosproject.yangutils.parser.Parsable;
@@ -34,7 +34,7 @@
 public class YangEnumeration extends YangNode implements Parsable, CollisionDetector {
 
     // Enumeration info set.
-    private Set<YangEnum> enumSet;
+    private SortedSet<YangEnum> enumSet;
 
     // Enumeration name.
     private String name;
@@ -44,7 +44,7 @@
      */
     public YangEnumeration() {
         super(YangNodeType.ENUMERATION_NODE);
-        setEnumSet(new HashSet<YangEnum>());
+        setEnumSet(new TreeSet<YangEnum>());
     }
 
     /**
@@ -52,7 +52,7 @@
      *
      * @return the ENUM set
      */
-    public Set<YangEnum> getEnumSet() {
+    public SortedSet<YangEnum> getEnumSet() {
         return enumSet;
     }
 
@@ -61,7 +61,7 @@
      *
      * @param enumSet the ENUM set to set
      */
-    private void setEnumSet(Set<YangEnum> enumSet) {
+    private void setEnumSet(SortedSet<YangEnum> enumSet) {
         this.enumSet = enumSet;
     }
 
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/datamodel/YangTypeDef.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/datamodel/YangTypeDef.java
index be2a5ed..a295b48 100644
--- a/utils/yangutils/src/main/java/org/onosproject/yangutils/datamodel/YangTypeDef.java
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/datamodel/YangTypeDef.java
@@ -21,6 +21,8 @@
 import org.onosproject.yangutils.parser.Parsable;
 import org.onosproject.yangutils.utils.YangConstructType;
 
+import static org.onosproject.yangutils.datamodel.utils.DataModelUtils.detectCollidingChildUtil;
+
 /*-
  * Reference RFC 6020.
  *
@@ -54,7 +56,7 @@
 /**
  * Represents data model node to maintain information defined in YANG typedef.
  */
-public class YangTypeDef extends YangNode implements YangCommonInfo, Parsable, YangTypeHolder {
+public class YangTypeDef extends YangNode implements YangCommonInfo, Parsable, YangTypeHolder, CollisionDetector {
 
     /**
      * Default value in string, needs to be converted to the target object,
@@ -272,4 +274,18 @@
     public List<YangType<?>> getTypeList() {
         return typeList;
     }
+
+    @Override
+    public void detectCollidingChild(String identifierName, YangConstructType dataType) throws DataModelException {
+        // Asks helper to detect colliding child.
+        detectCollidingChildUtil(identifierName, dataType, this);
+    }
+
+    @Override
+    public void detectSelfCollision(String identifierName, YangConstructType dataType) throws DataModelException {
+        if (getName().equals(identifierName)) {
+            throw new DataModelException("YANG file error: Duplicate input identifier detected, same as typedef \""
+                    + getName() + "\"");
+        }
+    }
 }