diff --git a/src/main/java/net/onrc/onos/intent/ConstrainedBFSTree.java b/src/main/java/net/onrc/onos/intent/ConstrainedBFSTree.java
new file mode 100644
index 0000000..2ea27ae
--- /dev/null
+++ b/src/main/java/net/onrc/onos/intent/ConstrainedBFSTree.java
@@ -0,0 +1,71 @@
+package net.onrc.onos.intent;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.LinkedList;
+
+import net.onrc.onos.ofcontroller.networkgraph.Link;
+import net.onrc.onos.ofcontroller.networkgraph.Path;
+import net.onrc.onos.ofcontroller.networkgraph.Switch;
+
+/**
+ * This class creates bandwidth constrained breadth first tree
+ * and returns paths from root switch to leaf switches
+ * which satisfies the bandwidth condition.
+ * If bandwidth parameter is not specified, the normal breadth first tree will be calculated.
+ * The paths are snapshot paths at the point of the class instantiation.
+ * @author Toshio Koide (t-koide@onlab.us)
+ */
+public class ConstrainedBFSTree {
+	LinkedList<Switch> switchQueue = new LinkedList<Switch>();
+	HashSet<Switch> switchSearched = new HashSet<Switch>();
+	HashMap<Switch, Link> upstreamLinks = new HashMap<Switch, Link>();
+	HashMap<Switch, Path> paths = new HashMap<Switch, Path>();
+	Switch rootSwitch;
+	PathIntents intents = null;
+	Double bandwidth = null;
+
+	public ConstrainedBFSTree(Switch rootSwitch) {
+		this.rootSwitch = rootSwitch;
+		this.intents = new PathIntents();
+		calcTree();
+	}
+
+	public ConstrainedBFSTree(Switch rootSwitch, PathIntents intents, Double bandwidth) {
+		this.rootSwitch = rootSwitch;
+		this.intents = intents;
+		this.bandwidth = bandwidth;
+		calcTree();
+	}
+
+	protected void calcTree() {
+		switchQueue.add(rootSwitch);
+		switchSearched.add(rootSwitch);
+		while (!switchQueue.isEmpty()) {
+			Switch sw = switchQueue.poll();
+			for (Link link: sw.getOutgoingLinks()) {
+				Switch reachedSwitch = link.getDestinationPort().getSwitch();
+				if (switchSearched.contains(reachedSwitch)) continue;
+				if (bandwidth != null && intents.getAvailableBandwidth(link) < bandwidth) continue;
+				switchQueue.add(reachedSwitch);
+				switchSearched.add(reachedSwitch);
+				upstreamLinks.put(reachedSwitch, link);
+			}
+		}
+	}
+
+	public Path getPath(Switch leafSwitch) {
+		Path path = paths.get(leafSwitch);
+		if (path == null && switchSearched.contains(leafSwitch)) {
+			path = new Path();
+			Switch sw = leafSwitch;
+			while (sw != rootSwitch) {
+				Link upstreamLink = upstreamLinks.get(sw);
+				path.add(0, upstreamLink);
+				sw = upstreamLink.getSourcePort().getSwitch();
+			}
+			paths.put(leafSwitch, path);
+		}
+		return path;
+	}
+}