diff --git a/providers/null/src/main/java/org/onosproject/provider/nil/TreeTopologySimulator.java b/providers/null/src/main/java/org/onosproject/provider/nil/TreeTopologySimulator.java
new file mode 100644
index 0000000..bed1390
--- /dev/null
+++ b/providers/null/src/main/java/org/onosproject/provider/nil/TreeTopologySimulator.java
@@ -0,0 +1,75 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.provider.nil;
+
+import static com.google.common.base.Preconditions.checkArgument;
+
+/**
+ * Tree topology with hosts at the leaf devices.
+ */
+public class TreeTopologySimulator extends TopologySimulator {
+
+    private int[] tierMultiplier;
+    private int[] tierDeviceCount;
+    private int[] tierOffset;
+
+    @Override
+    protected void processTopoShape(String shape) {
+        super.processTopoShape(shape);
+        tierOffset = new int[topoShape.length];
+        tierMultiplier = new int[topoShape.length];
+        tierDeviceCount = new int[topoShape.length];
+
+        deviceCount = 1;
+
+        tierOffset[0] = 0;
+        tierMultiplier[0] = 1;
+        tierDeviceCount[0] = deviceCount;
+
+        for (int i = 1; i < topoShape.length; i++) {
+            tierOffset[i] = deviceCount;
+            tierMultiplier[i] = Integer.parseInt(topoShape[i]);
+            tierDeviceCount[i] = tierDeviceCount[i - 1] * tierMultiplier[i];
+            deviceCount = deviceCount + tierDeviceCount[i];
+        }
+    }
+
+    @Override
+    public void setUpTopology() {
+        checkArgument(tierDeviceCount.length > 0, "There must be at least one tree tier");
+        super.setUpTopology();
+    }
+
+    @Override
+    protected void createLinks() {
+        for (int t = 1; t < tierOffset.length; t++) {
+            int child = tierOffset[t];
+            for (int parent = tierOffset[t - 1]; parent < tierOffset[t]; parent++) {
+                for (int i = 0; i < tierMultiplier[t]; i++) {
+                    createLink(parent, child);
+                    child++;
+                }
+            }
+        }
+    }
+
+    @Override
+    protected void createHosts() {
+        for (int i = tierOffset[tierOffset.length - 1]; i < deviceCount; i++) {
+            createHosts(deviceIds.get(i), hostCount);
+        }
+    }
+}