diff --git a/README.md b/README.md
index b71b9aa..9f2c040 100644
--- a/README.md
+++ b/README.md
@@ -15,12 +15,12 @@
 
 0. Install custom jars and dependencies (needs to be run only once)
 
-    $ ./setup-local-maven.sh
+        $ ./setup-local-maven.sh
 
 1. Cleanly build ONOS
 
-    $ mvn clean
-    $ mvn compile
+        $ mvn clean
+        $ mvn compile
 
     NOTE: installing maven for the first time may switch java version
     from 1.7 to 1.6. This might prevent Cassandra to run.
@@ -28,17 +28,19 @@
 Dependencies
 ------------
 1. Zookeeper
+
     Download and install apache-zookeeper-3.4.5:
     http://zookeeper.apache.org/releases.html
 
-    Edit file (ONOS-INSTALL-DIR)/start-zk.sh and set variable "ZK_DIR"
+    Edit file `(ONOS-INSTALL-DIR)/start-zk.sh` and set variable "ZK_DIR"
     to point to the Zookeeper directory.
 
 2. Cassandra
+
     Download and install apache-cassandra-1.2.4:
     http://cassandra.apache.org/download/
 
-    Edit file (ONOS-INSTALL-DIR)/start-cassandra.sh and set variable
+    Edit file `(ONOS-INSTALL-DIR)/start-cassandra.sh` and set variable
     "CASSANDRA_DIR" to point to the Cassandra directory.
 
 Running ONOS with Cassandra as a separate process
@@ -47,62 +49,62 @@
 
 1. Start Zookeeper
 
-    $ cd (ONOS-INSTALL-DIR)/
-    $ ./start-zk.sh start
+        $ cd (ONOS-INSTALL-DIR)/
+        $ ./start-zk.sh start
 
-    ## Confirm Zookeeper is running:
-    $ ./start.zk.sh status
+        ## Confirm Zookeeper is running:
+        $ ./start.zk.sh status
 
 2. Start Cassandra
 
-    $ cd (ONOS-INSTALL-DIR)/
-    $ ./start-cassandra.sh start
+        $ cd (ONOS-INSTALL-DIR)/
+        $ ./start-cassandra.sh start
 
-    ## Confirm Cassandra is running:
-    $ ./start-cassandra.sh status
+        ## Confirm Cassandra is running:
+        $ ./start-cassandra.sh status
 
 3. Start ONOS
 
-    $ cd (ONOS-INSTALL-DIR)/
-    $ ./start-onos.sh start
+        $ cd (ONOS-INSTALL-DIR)/
+        $ ./start-onos.sh start
 
-    ## Confirm ONOS is running:
-    $ ./start-onos.sh status
-    
+        ## Confirm ONOS is running:
+        $ ./start-onos.sh status
+
 4. Start ONOS REST API server
 
-    $ cd (ONOS-INSTALL-DIR)/
-    $ ./start-rest.sh start
+        $ cd (ONOS-INSTALL-DIR)/
+        $ ./start-rest.sh start
 
-    ## Confirm the REST API server is running:
-    $ ./start-rest.sh status
+        ## Confirm the REST API server is running:
+        $ ./start-rest.sh status
 
 Running ONOS with Cassandra embedded (Optional)
 -----------------------------------------------
 
 1. Start Zookeeper
 
-    $ cd (ONOS-INSTALL-DIR)/
-    $ ./start-zk.sh start
+        $ cd (ONOS-INSTALL-DIR)/
+        $ ./start-zk.sh start
 
-    ## Confirm Zookeeper is running:
-    $ ./start.zk.sh status
-    
+        ## Confirm Zookeeper is running:
+        $ ./start.zk.sh status
+
 2. Start ONOS and Cassandra embedded
 
-    $ cd (ONOS-INSTALL_DIR)/
-    $ ./start-onos-embedded.sh start
+        $ cd (ONOS-INSTALL_DIR)/
+        $ ./start-onos-embedded.sh start
 
-    ## Confirm ONOS is running:
-    $ ./start-onos-embedded.sh status
-    
+        ## Confirm ONOS is running:
+        $ ./start-onos-embedded.sh status
+
 3. Start ONOS REST API server
 
-    $ cd (ONOS-INSTALL-DIR)/
-    $ ./start-rest.sh start
+        $ cd (ONOS-INSTALL-DIR)/
+        $ ./start-rest.sh start
 
-    ## Confirm the REST API server is running:
-    $ ./start-rest.sh status
+        ## Confirm the REST API server is running:
+        $ ./start-rest.sh status
 
 
 Running in offline mode (Optional)
@@ -110,9 +112,9 @@
 
 Maven is used to build and run ONOS. By default, maven tries to reach
 the repositories. The '-o' option can be given to the 'mvn' command to
-suppress this behavior. The MVN environmental variable can be used to
+suppress this behavior. The `MVN` environmental variable can be used to
 set additional options to the 'mvn' command used in ONOS.
 
 * Example: Running in offline mode
 
-    $ env MVN="mvn -o" ./start-onos.sh start
+        $ env MVN="mvn -o" ./start-onos.sh start
diff --git a/cluster-mgmt/bin/cho-link-failure.sh b/cluster-mgmt/bin/cho-link-failure.sh
index 6c5f128..4db887a 100755
--- a/cluster-mgmt/bin/cho-link-failure.sh
+++ b/cluster-mgmt/bin/cho-link-failure.sh
@@ -16,7 +16,6 @@
 dsh -w ${basename}1 "cd ONOS/scripts; ./all-linkup.sh"
 echo "clean up flow"
 dsh -w ${basename}1 "cd ONOS/web; ./delete_flow.py 1 100"
-dsh -w ${basename}1 "cd ONOS/web; ./clear_flow.py 1 100"
 sleep 1
 dsh -w ${basename}1 "cd ONOS/web; ./get_flow.py all"
 dsh "cd ONOS/scripts; ./delflow.sh"
diff --git a/cluster-mgmt/bin/demo-reset-hw.sh b/cluster-mgmt/bin/demo-reset-hw.sh
index 8c586f5..15f97e1 100755
--- a/cluster-mgmt/bin/demo-reset-hw.sh
+++ b/cluster-mgmt/bin/demo-reset-hw.sh
@@ -9,7 +9,6 @@
 
 echo "cleanup excess flows"
 $DIR/web/delete_flow.py 201 300
-$DIR/web/clear_flow.py 201 300
 echo "cleanup excess flows done"
 echo "Adding 200 flows"
 $DIR/web/add_flow.py -m onos -f $DIR/web/flowdef_demo_start.txt
diff --git a/cluster-mgmt/bin/test-link-failure.sh b/cluster-mgmt/bin/test-link-failure.sh
index 6c5f128..4db887a 100755
--- a/cluster-mgmt/bin/test-link-failure.sh
+++ b/cluster-mgmt/bin/test-link-failure.sh
@@ -16,7 +16,6 @@
 dsh -w ${basename}1 "cd ONOS/scripts; ./all-linkup.sh"
 echo "clean up flow"
 dsh -w ${basename}1 "cd ONOS/web; ./delete_flow.py 1 100"
-dsh -w ${basename}1 "cd ONOS/web; ./clear_flow.py 1 100"
 sleep 1
 dsh -w ${basename}1 "cd ONOS/web; ./get_flow.py all"
 dsh "cd ONOS/scripts; ./delflow.sh"
diff --git a/cluster-mgmt/template/onsdemo_edge_template.py b/cluster-mgmt/template/onsdemo_edge_template.py
index e340f38..c3d0287 100755
--- a/cluster-mgmt/template/onsdemo_edge_template.py
+++ b/cluster-mgmt/template/onsdemo_edge_template.py
@@ -65,7 +65,7 @@
             switch.append(sw)
 
         for i in range (NR_NODES):
-            host.append(self.addHost( 'host%d' % (int(i)+1) ))
+            host.append(self.addHost( 'host%d.%d' % (NWID, int(i)+1) ))
 
         for i in range (NR_NODES):
             self.addLink(host[i], switch[i])
@@ -117,7 +117,7 @@
 
     host = []
     for i in range (NR_NODES):
-      host.append(net.get( 'host%d' % (int(i)+1) ))
+      host.append(net.get( 'host%d.%d' % (NWID, (int(i)+1)) ))
 
     net.start()
 
diff --git a/kryo2/pom.xml b/kryo2/pom.xml
index 1beb87d..788f952 100644
--- a/kryo2/pom.xml
+++ b/kryo2/pom.xml
@@ -7,7 +7,7 @@
   <version>2.22</version>
   <packaging>jar</packaging>
 
-  <name>kyro2</name>
+  <name>kryo2</name>
   <url>http://maven.apache.org</url>
 
   <properties>
diff --git a/scripts/demo-reset-sw.sh b/scripts/demo-reset-sw.sh
index 65a2ff1..e6cabae 100755
--- a/scripts/demo-reset-sw.sh
+++ b/scripts/demo-reset-sw.sh
@@ -6,7 +6,6 @@
 $DIR/scripts/all-linkup.sh
 echo "Delete Flows"
 $DIR/web/delete_flow.py 201 300
-$DIR/web/clear_flow.py 201 300
 echo "Adding Flows"
 $DIR/web/add_flow.py -m onos -f $DIR/web/flowdef_demo_start.txt
 ssh -i ~/.ssh/onlabkey.pem  ${basename}5 'ONOS/start-onos.sh stop'
diff --git a/src/main/java/net/onrc/onos/datagrid/HazelcastDatagrid.java b/src/main/java/net/onrc/onos/datagrid/HazelcastDatagrid.java
index 180cbe9..775f952 100644
--- a/src/main/java/net/onrc/onos/datagrid/HazelcastDatagrid.java
+++ b/src/main/java/net/onrc/onos/datagrid/HazelcastDatagrid.java
@@ -607,6 +607,29 @@
     }
 
     /**
+     * Get a Flow for a given Flow ID.
+     *
+     * @param flowId the Flow ID of the Flow to get.
+     * @return the Flow if found, otherwise null.
+     */
+    @Override
+    public FlowPath getFlow(FlowId flowId) {
+	byte[] valueBytes = mapFlow.get(flowId.value());
+	if (valueBytes == null)
+	    return null;
+
+	Kryo kryo = kryoFactory.newKryo();
+	//
+	// Decode the value
+	//
+	Input input = new Input(valueBytes);
+	FlowPath flowPath = kryo.readObject(input, FlowPath.class);
+	kryoFactory.deleteKryo(kryo);
+
+	return flowPath;
+    }
+
+    /**
      * Send a notification that a Flow is added.
      *
      * @param flowPath the Flow that is added.
@@ -702,6 +725,29 @@
     }
 
     /**
+     * Get a Flow Entry for a given Flow Entry ID.
+     *
+     * @param flowEntryId the Flow Entry ID of the Flow Entry to get.
+     * @return the Flow Entry if found, otherwise null.
+     */
+    @Override
+    public FlowEntry getFlowEntry(FlowEntryId flowEntryId) {
+	byte[] valueBytes = mapFlowEntry.get(flowEntryId.value());
+	if (valueBytes == null)
+	    return null;
+
+	Kryo kryo = kryoFactory.newKryo();
+	//
+	// Decode the value
+	//
+	Input input = new Input(valueBytes);
+	FlowEntry flowEntry = kryo.readObject(input, FlowEntry.class);
+	kryoFactory.deleteKryo(kryo);
+
+	return flowEntry;
+    }
+
+    /**
      * Send a notification that a FlowEntry is added.
      *
      * @param flowEntry the FlowEntry that is added.
diff --git a/src/main/java/net/onrc/onos/datagrid/IDatagridService.java b/src/main/java/net/onrc/onos/datagrid/IDatagridService.java
index 9361341..034fe25 100644
--- a/src/main/java/net/onrc/onos/datagrid/IDatagridService.java
+++ b/src/main/java/net/onrc/onos/datagrid/IDatagridService.java
@@ -50,7 +50,7 @@
      * @param arpEventHandler The ARP event handler to de-register.
      */
     public void deregisterArpEventHandler(IArpEventHandler arpEventHandler);
-    
+
     /**
      * Get all Flows that are currently in the datagrid.
      *
@@ -59,6 +59,14 @@
     Collection<FlowPath> getAllFlows();
 
     /**
+     * Get a Flow for a given Flow ID.
+     *
+     * @param flowId the Flow ID of the Flow to get.
+     * @return the Flow if found, otherwise null.
+     */
+    FlowPath getFlow(FlowId flowId);
+
+    /**
      * Send a notification that a Flow is added.
      *
      * @param flowPath the Flow that is added.
@@ -92,6 +100,14 @@
     Collection<FlowEntry> getAllFlowEntries();
 
     /**
+     * Get a Flow Entry for a given Flow Entry ID.
+     *
+     * @param flowEntryId the Flow Entry ID of the Flow Entry to get.
+     * @return the Flow Entry if found, otherwise null.
+     */
+    FlowEntry getFlowEntry(FlowEntryId flowEntryId);
+
+    /**
      * Send a notification that a FlowEntry is added.
      *
      * @param flowEntry the FlowEntry that is added.
diff --git a/src/main/java/net/onrc/onos/flow/FlowManagerImpl.java b/src/main/java/net/onrc/onos/flow/FlowManagerImpl.java
deleted file mode 100644
index 9865deb..0000000
--- a/src/main/java/net/onrc/onos/flow/FlowManagerImpl.java
+++ /dev/null
@@ -1,331 +0,0 @@
-package net.onrc.onos.flow;
-
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.LinkedList;
-import java.util.List;
-import java.util.Map;
-import java.util.Queue;
-import java.util.Set;
-
-import org.openflow.util.HexString;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-import com.tinkerpop.blueprints.Direction;
-import com.tinkerpop.blueprints.Vertex;
-
-import net.floodlightcontroller.core.IOFSwitch;
-import net.onrc.onos.graph.GraphDBOperation;
-import net.onrc.onos.graph.LocalTopologyEventListener;
-import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IFlowEntry;
-import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IFlowPath;
-import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IPortObject;
-import net.onrc.onos.ofcontroller.core.ISwitchStorage.SwitchState;
-import net.onrc.onos.ofcontroller.util.DataPath;
-import net.onrc.onos.ofcontroller.util.Dpid;
-import net.onrc.onos.ofcontroller.util.FlowEntry;
-import net.onrc.onos.ofcontroller.util.FlowEntryAction;
-import net.onrc.onos.ofcontroller.util.FlowEntryActions;
-import net.onrc.onos.ofcontroller.util.FlowEntryMatch;
-import net.onrc.onos.ofcontroller.util.FlowPath;
-import net.onrc.onos.ofcontroller.util.Port;
-import net.onrc.onos.ofcontroller.util.SwitchPort;
-
-public class FlowManagerImpl implements IFlowManager {
-	
-	protected final static Logger log = LoggerFactory.getLogger(LocalTopologyEventListener.class);
-	protected GraphDBOperation op;
-
-	@Override
-	public void createFlow(IPortObject src_port, IPortObject dest_port) {
-		// TODO Auto-generated method stub
-
-	}
-
-	@Override
-	public Iterable<FlowPath> getFlows(IPortObject src_port,
-			IPortObject dest_port) {
-		// TODO Auto-generated method stub
-		return null;
-	}
-
-	@Override
-	public Iterable<FlowPath> getOutFlows(IPortObject port) {
-		// TODO Auto-generated method stub
-		List<FlowPath> flowPaths = new ArrayList<FlowPath> ();
-		Iterable<IFlowEntry> flowEntries = port.getOutFlowEntries();
-
-		for(IFlowEntry fe: flowEntries) {
-			IFlowPath flow = fe.getFlow();
-			FlowPath flowPath = new FlowPath(flow);
-			flowPaths.add(flowPath);
-		}
-		return flowPaths;
-	}
-
-	@Override
-	public void reconcileFlows(IPortObject src_port) {
-		// TODO Auto-generated method stub
-
-		log.debug("Reconcile Flows for Port removed: {}:{}",src_port.getSwitch().getDPID(),src_port.getNumber());
-		Iterable<IFlowEntry> flowEntries = src_port.getOutFlowEntries();
-
-		for(IFlowEntry fe: flowEntries) {
-			IFlowPath flow = fe.getFlow();
-			reconcileFlow(flow);
-		}
-	}
-
-	private void reconcileFlow(IFlowPath flow) {
-		// TODO Auto-generated method stub
-		String src_dpid = flow.getSrcSwitch();
-		String dst_dpid = flow.getDstSwitch();
-		Short src_port = flow.getSrcPort();
-		Short dst_port = flow.getDstPort();
-		IPortObject src = null;
-		IPortObject dst = null;
-		src = op.searchPort(src_dpid, src_port);
-		dst = op.searchPort(dst_dpid, dst_port);
-		if (src != null && dst != null) {
-			FlowPath newFlow = this.computeFlowPath(src,dst);
-			installFlow(newFlow);
-			removeFlow(flow);
-		}
-		
-	}
-
-	private void removeFlow(IFlowPath flow) {
-		// TODO Auto-generated method stub
-		
-	}
-
-	private void installFlow(FlowPath newFlow) {
-		// TODO Auto-generated method stub
-		
-	}
-
-	@Override
-	public void reconcileFlow(IPortObject src_port, IPortObject dest_port) {
-		// TODO Auto-generated method stub
-
-	}
-
-	@Override
-	public FlowPath computeFlowPath(IPortObject src_port, IPortObject dest_port) {
-		// TODO Auto-generated method stub
-		DataPath dataPath = new DataPath(); 
-		
-		// FIXME: Bad idea to use FloodLight data structures (SwitchPort)
-		
-		dataPath.setSrcPort(new SwitchPort(new Dpid(src_port.getSwitch().getDPID()),
-						new Port(src_port.getNumber())));
-		dataPath.setDstPort(new SwitchPort(new Dpid(src_port.getSwitch().getDPID()),
-				new Port(src_port.getNumber())));
-		
-		if (src_port.getSwitch().equals(dest_port.getSwitch())) {
-			// on same switch create quick path
-			FlowEntry flowEntry = new FlowEntry();
-		    flowEntry.setDpid(new Dpid(src_port.getSwitch().getDPID()));
-		    flowEntry.setInPort(new Port(src_port.getNumber()));
-		    flowEntry.setOutPort(new Port(src_port.getNumber()));
-		    flowEntry.setFlowEntryMatch(new FlowEntryMatch());
-		    flowEntry.flowEntryMatch().enableInPort(flowEntry.inPort());
-
-		    // Set the outgoing port output action
-		    FlowEntryActions flowEntryActions = flowEntry.flowEntryActions();
-		    FlowEntryAction flowEntryAction = new FlowEntryAction();
-		    flowEntryAction.setActionOutput(flowEntry.outPort());
-		    flowEntryActions.addAction(flowEntryAction);
-		    dataPath.flowEntries().add(flowEntry);
-		    
-		    FlowPath flowPath = new FlowPath();
-			flowPath.setDataPath(dataPath);
-
-			return flowPath;
-		}
-		Vertex v_src = src_port.getSwitch().asVertex();	
-		Vertex v_dest = dest_port.getSwitch().asVertex();
-
-		//
-		// Implement the Shortest Path computation by using Breath First Search
-		//
-		Set<Vertex> visitedSet = new HashSet<Vertex>();
-		Queue<Vertex> processingList = new LinkedList<Vertex>();
-		Map<Vertex, Vertex> previousVertexMap = new HashMap<Vertex, Vertex>();
-
-		processingList.add(v_src);
-		visitedSet.add(v_src);
-		Boolean path_found = false;
-		while (! processingList.isEmpty()) {
-		    Vertex nextVertex = processingList.poll();
-		    if (v_dest.equals(nextVertex)) {
-			path_found = true;
-			break;
-		    }
-		    for (Vertex parentPort : nextVertex.getVertices(Direction.OUT, "on")) {
-			for (Vertex childPort : parentPort.getVertices(Direction.OUT, "link")) {
-			    for (Vertex child : childPort.getVertices(Direction.IN, "on")) {
-				// Ignore inactive switches
-				String state = child.getProperty("state").toString();
-				if (! state.equals(SwitchState.ACTIVE.toString()))
-				    continue;
-
-				if (! visitedSet.contains(child)) {
-				    previousVertexMap.put(parentPort, nextVertex);
-				    previousVertexMap.put(childPort, parentPort);
-				    previousVertexMap.put(child, childPort);
-				    visitedSet.add(child);
-				    processingList.add(child);
-				}
-			    }
-			}
-		    }
-		}
-		if (! path_found) {
-		    return null;		// No path found
-		}
-
-		List<Vertex> resultPath = new LinkedList<Vertex>();
-		Vertex previousVertex = v_dest;
-		resultPath.add(v_dest);
-		while (! v_src.equals(previousVertex)) {
-		    Vertex currentVertex = previousVertexMap.get(previousVertex);
-		    resultPath.add(currentVertex);
-		    previousVertex = currentVertex;
-		}
-		Collections.reverse(resultPath);
-		
-		// Loop through the result and prepare the return result
-		// as a list of Flow Entries.
-		//
-		long nodeId = 0;
-		short portId = 0;
-		Port inPort = new Port(src_port.getNumber());
-		Port outPort = new Port();
-		int idx = 0;
-		for (Vertex v: resultPath) {
-		    String type = v.getProperty("type").toString();
-		    // System.out.println("type: " + type);
-		    if (type.equals("port")) {
-			//String number = v.getProperty("number").toString();
-			// System.out.println("number: " + number);
-
-			Object obj = v.getProperty("number");
-			// String class_str = obj.getClass().toString();
-			if (obj instanceof Short) {
-			    portId = (Short)obj;
-			} else if (obj instanceof Integer) {
-			    Integer int_nodeId = (Integer)obj;
-			    portId = int_nodeId.shortValue();
-			    // int int_nodeId = (Integer)obj;
-			    // portId = (short)int_nodeId.;
-			}
-		    } else if (type.equals("switch")) {
-			String dpid = v.getProperty("dpid").toString();
-			nodeId = HexString.toLong(dpid);
-
-			// System.out.println("dpid: " + dpid);
-		    }
-		    idx++;
-		    if (idx == 1) {
-			continue;
-		    }
-		    int mod = idx % 3;
-		    if (mod == 0) {
-			// Setup the incoming port
-			inPort = new Port(portId);
-			continue;
-		    }
-		    if (mod == 2) {
-			// Setup the outgoing port, and add the Flow Entry
-			outPort = new Port(portId);
-
-			FlowEntry flowEntry = new FlowEntry();
-			flowEntry.setDpid(new Dpid(nodeId));
-			flowEntry.setInPort(inPort);
-			flowEntry.setOutPort(outPort);
-			flowEntry.setFlowEntryMatch(new FlowEntryMatch());
-		    flowEntry.flowEntryMatch().enableInPort(flowEntry.inPort());
-		    
-		    // Set the outgoing port output action
-		    FlowEntryActions flowEntryActions = flowEntry.flowEntryActions();
-		    FlowEntryAction flowEntryAction = new FlowEntryAction();
-		    flowEntryAction.setActionOutput(flowEntry.outPort());
-		    flowEntryActions.addAction(flowEntryAction);
-		    dataPath.flowEntries().add(flowEntry);
-			continue;
-		    }
-		}
-		if (idx > 0) {
-		    // Add the last Flow Entry
-		    FlowEntry flowEntry = new FlowEntry();
-		    flowEntry.setDpid(new Dpid(nodeId));
-		    flowEntry.setInPort(inPort);
-		    flowEntry.setOutPort(new Port(dest_port.getNumber()));
-		    flowEntry.setFlowEntryMatch(new FlowEntryMatch());
-		    flowEntry.flowEntryMatch().enableInPort(flowEntry.inPort());
-		    
-		    // Set the outgoing port output action
-		    FlowEntryActions flowEntryActions = flowEntry.flowEntryActions();
-		    FlowEntryAction flowEntryAction = new FlowEntryAction();
-		    flowEntryAction.setActionOutput(flowEntry.outPort());
-		    flowEntryActions.addAction(flowEntryAction);
-		    dataPath.flowEntries().add(flowEntry);
-		    // TODO (BOC): why is this twice?
-		    dataPath.flowEntries().add(flowEntry);
-		}
-
-	
-		if (dataPath.flowEntries().size() > 0) {
-		    FlowPath flowPath = new FlowPath();
-			flowPath.setDataPath(dataPath);
-
-			return flowPath;
-		}
-		return null;		
-		
-	}
-
-	@Override
-	public Iterable<FlowEntry> getFlowEntries(FlowPath flow) {
-		// TODO Auto-generated method stub
-		return null;
-	}
-
-
-	@Override
-	public boolean installRemoteFlowEntry(FlowPath flowPath,
-					      FlowEntry entry) {
-		// TODO Auto-generated method stub
-		return false;
-	}
-
-	@Override
-	public boolean removeRemoteFlowEntry(FlowPath flowPath,
-					     FlowEntry entry) {
-		return false;
-		// TODO Auto-generated method stub
-
-	}
-
-	@Override
-	public boolean installFlowEntry(IOFSwitch mySwitch,
-					FlowPath flowPath,
-					FlowEntry flowEntry) {
-		// TODO Auto-generated method stub
-		return false;
-	}
-
-	@Override
-	public boolean removeFlowEntry(IOFSwitch mySwitch,
-				       FlowPath flowPath,
-				       FlowEntry flowEntry) {
-		// TODO Auto-generated method stub
-		return false;
-	}
-	
-
-}
diff --git a/src/main/java/net/onrc/onos/flow/IFlowManager.java b/src/main/java/net/onrc/onos/flow/IFlowManager.java
deleted file mode 100644
index 598da85..0000000
--- a/src/main/java/net/onrc/onos/flow/IFlowManager.java
+++ /dev/null
@@ -1,126 +0,0 @@
-package net.onrc.onos.flow;
-
-import net.floodlightcontroller.core.IOFSwitch;
-import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IPortObject;
-import net.onrc.onos.ofcontroller.util.FlowEntry;
-import net.onrc.onos.ofcontroller.util.FlowPath;
-
-public interface IFlowManager {
-    /**
-     * Create a Flow from port to port.
-     *
-     * TODO: We don't need it for now.
-     *
-     * @param src_port the source port.
-     * @param dest_port the destination port.
-     */
-    public void createFlow(IPortObject src_port, IPortObject dest_port);
-
-    /**
-     * Get all Flows matching a source and a destination port.
-     *
-     * TODO: Pankaj might be implementing it later.
-     *
-     * @param src_port the source port to match.
-     * @param dest_port the destination port to match.
-     * @return all flows matching the source and the destination port.
-     */
-    public Iterable<FlowPath> getFlows(IPortObject src_port,
-				       IPortObject dest_port);
-
-    /**
-     * Get all Flows going out from a port.
-     *
-     * TODO: We need it now: Pankaj
-     *
-     * @param port the port to match.
-     * @return the list of flows that are going out from the port.
-     */
-    public Iterable<FlowPath> getOutFlows(IPortObject port);
-
-    /**
-     * Reconcile all flows on inactive switch port.
-     *
-     * @param portObject the port that has become inactive.
-     */
-    public void reconcileFlows(IPortObject portObject);
-
-    /**
-     * Reconcile all flows between a source and a destination port.
-     *
-     * TODO: We don't need it for now.
-     *
-     * @param src_port the source port.
-     * @param dest_port the destination port.
-     */
-    public void reconcileFlow(IPortObject src_port, IPortObject dest_port);
-
-    /**
-     * Compute the shortest path between a source and a destination ports.
-     *
-     * @param src_port the source port.
-     * @param dest_port the destination port.
-     * @return the computed shortest path between the source and the
-     * destination ports. The flow entries in the path itself would
-     * contain the incoming port matching and the outgoing port output
-     * actions set. However, the path itself will NOT have the Flow ID,
-     * Installer ID, and any additional matching conditions for the
-     * flow entries (e.g., source or destination MAC address, etc).
-     */
-    public FlowPath computeFlowPath(IPortObject src_port,
-				    IPortObject dest_port);
-
-    /**
-     * Get all Flow Entries of a Flow.
-     *
-     * @param flow the flow whose flow entries should be returned.
-     * @return the flow entries of the flow.
-     */
-    public Iterable<FlowEntry> getFlowEntries(FlowPath flow);
-
-    /**
-     * Install a Flow Entry on a switch.
-     *
-     * @param mySwitch the switch to install the Flow Entry into.
-     * @param flowPath the flow path for the flow entry to install.
-     * @param flowEntry the flow entry to install.
-     * @return true on success, otherwise false.
-     */
-    public boolean installFlowEntry(IOFSwitch mySwitch, FlowPath flowPath,
-				    FlowEntry flowEntry);
-
-    /**
-     * Remove a Flow Entry from a switch.
-     *
-     * @param mySwitch the switch to remove the Flow Entry from.
-     * @param flowPath the flow path for the flow entry to remove.
-     * @param flowEntry the flow entry to remove.
-     * @return true on success, otherwise false.
-     */
-    public boolean removeFlowEntry(IOFSwitch mySwitch, FlowPath flowPath,
-				   FlowEntry flowEntry);
-
-    /**
-     * Install a Flow Entry on a remote controller.
-     *
-     * TODO: We need it now: Jono
-     * - For now it will make a REST call to the remote controller.
-     * - Internally, it needs to know the name of the remote controller.
-     *
-     * @param flowPath the flow path for the flow entry to install.
-     * @param flowEntry the flow entry to install.
-     * @return true on success, otherwise false.
-     */
-    public boolean installRemoteFlowEntry(FlowPath flowPath,
-					  FlowEntry flowEntry);
-
-    /**
-     * Remove a flow entry on a remote controller.
-     *
-     * @param flowPath the flow path for the flow entry to remove.
-     * @param flowEntry the flow entry to remove.
-     * @return true on success, otherwise false.
-     */
-    public boolean removeRemoteFlowEntry(FlowPath flowPath,
-					 FlowEntry flowEntry);
-}
diff --git a/src/main/java/net/onrc/onos/graph/LocalTopologyEventListener.java b/src/main/java/net/onrc/onos/graph/LocalTopologyEventListener.java
index 5388233..40f5044 100644
--- a/src/main/java/net/onrc/onos/graph/LocalTopologyEventListener.java
+++ b/src/main/java/net/onrc/onos/graph/LocalTopologyEventListener.java
@@ -1,7 +1,5 @@
 package net.onrc.onos.graph;
 
-import net.onrc.onos.flow.FlowManagerImpl;
-import net.onrc.onos.flow.IFlowManager;
 import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IPortObject;
 
 import org.slf4j.Logger;
@@ -52,9 +50,12 @@
 																src_port.getNumber(),
 																dest_port.getSwitch().getDPID(),
 																dest_port.getNumber()});
-			IFlowManager manager = new FlowManagerImpl();
 			// TODO: Find the flows and add to reconcile queue
-			manager.reconcileFlows(src_port);
+			//
+			// NOTE: Old code/logic.
+			//
+			// IFlowService flowManager = ...
+			// flowManager.reconcileFlows(src_port);
 		}
 	}
 
@@ -81,8 +82,11 @@
 			
 			IPortObject src_port = conn.getFramedGraph().frame(vertex, IPortObject.class);
 			log.debug("TopologyEvents: Port removed: {}:{}",src_port.getSwitch().getDPID(),src_port.getNumber());
-			IFlowManager manager = new FlowManagerImpl();
-			manager.reconcileFlows(src_port);			
+
+			// NOTE: Old code/logic.
+			//
+			// IFlowService flowManager = ...
+			// flowManager.reconcileFlows(src_port);
 		}
 	}
 
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowDatabaseOperation.java b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowDatabaseOperation.java
index f623541..71479a1 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowDatabaseOperation.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowDatabaseOperation.java
@@ -25,7 +25,7 @@
 /**
  * Class for performing Flow-related operations on the Database.
  */
-class FlowDatabaseOperation {
+public class FlowDatabaseOperation {
     private final static Logger log = LoggerFactory.getLogger(FlowDatabaseOperation.class);
 
     /**
@@ -68,6 +68,21 @@
 	}
 
 	//
+	// Remove the old Flow Entries
+	//
+	if (found) {
+	    Iterable<IFlowEntry> flowEntries = flowObj.getFlowEntries();
+	    LinkedList<IFlowEntry> deleteFlowEntries =
+		new LinkedList<IFlowEntry>();
+	    for (IFlowEntry flowEntryObj : flowEntries)
+		deleteFlowEntries.add(flowEntryObj);
+	    for (IFlowEntry flowEntryObj : deleteFlowEntries) {
+		flowObj.removeFlowEntry(flowEntryObj);
+		dbHandler.removeFlowEntry(flowEntryObj);
+	    }
+	}
+
+	//
 	// Set the Flow key:
 	// - flowId
 	//
@@ -155,6 +170,9 @@
 	// flowPath.dataPath().flowEntries()
 	//
 	for (FlowEntry flowEntry : flowPath.dataPath().flowEntries()) {
+	    if (flowEntry.flowEntryUserState() == FlowEntryUserState.FE_USER_DELETE)
+		continue;	// Skip: all Flow Entries were deleted earlier
+
 	    if (addFlowEntry(flowManager, dbHandler, flowObj, flowEntry) == null) {
 		dbHandler.rollback();
 		return false;
@@ -186,15 +204,6 @@
 	// Flow edges
 	//   HeadFE (TODO)
 
-	//
-	// Assign the FlowEntry ID.
-	//
-	if ((flowEntry.flowEntryId() == null) ||
-	    (flowEntry.flowEntryId().value() == 0)) {
-	    long id = flowManager.getNextFlowEntryId();
-	    flowEntry.setFlowEntryId(new FlowEntryId(id));
-	}
-
 	IFlowEntry flowEntryObj = null;
 	boolean found = false;
 	try {
@@ -370,122 +379,6 @@
      * @return true on success, otherwise false.
      */
     static boolean deleteAllFlows(GraphDBOperation dbHandler) {
-	final ConcurrentLinkedQueue<FlowId> concurrentAllFlowIds =
-	    new ConcurrentLinkedQueue<FlowId>();
-
-	// Get all Flow IDs
-	Iterable<IFlowPath> allFlowPaths = dbHandler.getAllFlowPaths();
-	for (IFlowPath flowPathObj : allFlowPaths) {
-	    if (flowPathObj == null)
-		continue;
-	    String flowIdStr = flowPathObj.getFlowId();
-	    if (flowIdStr == null)
-		continue;
-	    FlowId flowId = new FlowId(flowIdStr);
-	    concurrentAllFlowIds.add(flowId);
-	}
-
-	// Delete all flows one-by-one
-	for (FlowId flowId : concurrentAllFlowIds)
-	    deleteFlow(dbHandler, flowId);
-
-	/*
-	 * TODO: A faster mechanism to delete the Flow Paths by using
-	 * a number of threads. Commented-out for now.
-	 */
-	/*
-	//
-	// Create the threads to delete the Flow Paths
-	//
-	List<Thread> threads = new LinkedList<Thread>();
-	for (int i = 0; i < 10; i++) {
-	    Thread thread = new Thread(new Runnable() {
-		@Override
-		public void run() {
-		    while (true) {
-			FlowId flowId = concurrentAllFlowIds.poll();
-			if (flowId == null)
-			    return;
-			deleteFlow(dbHandler, flowId);
-		    }
-		}}, "Delete All Flow Paths");
-	    threads.add(thread);
-	}
-
-	// Start processing
-	for (Thread thread : threads) {
-	    thread.start();
-	}
-
-	// Wait for all threads to complete
-	for (Thread thread : threads) {
-	    try {
-		thread.join();
-	    } catch (InterruptedException e) {
-		log.debug("Exception waiting for a thread to delete a Flow Path: ", e);
-	    }
-	}
-	*/
-
-	return true;
-    }
-
-    /**
-     * Delete a previously added flow.
-     *
-     * @param dbHandler the Graph Database handler to use.
-     * @param flowId the Flow ID of the flow to delete.
-     * @return true on success, otherwise false.
-     */
-    static boolean deleteFlow(GraphDBOperation dbHandler, FlowId flowId) {
-	IFlowPath flowObj = null;
-	//
-	// We just mark the entries for deletion,
-	// and let the switches remove each individual entry after
-	// it has been removed from the switches.
-	//
-	try {
-	    flowObj = dbHandler.searchFlowPath(flowId);
-	} catch (Exception e) {
-	    // TODO: handle exceptions
-	    dbHandler.rollback();
-	    log.error(":deleteFlow FlowId:{} failed", flowId.toString());
-	    return false;
-	}
-	if (flowObj == null) {
-	    dbHandler.commit();
-	    return true;		// OK: No such flow
-	}
-
-	//
-	// Find and mark for deletion all Flow Entries,
-	// and the Flow itself.
-	//
-	flowObj.setFlowPathUserState("FP_USER_DELETE");
-	Iterable<IFlowEntry> flowEntries = flowObj.getFlowEntries();
-	boolean empty = true;	// TODO: an ugly hack
-	for (IFlowEntry flowEntryObj : flowEntries) {
-	    empty = false;
-	    // flowObj.removeFlowEntry(flowEntryObj);
-	    // conn.utils().removeFlowEntry(conn, flowEntryObj);
-	    flowEntryObj.setUserState("FE_USER_DELETE");
-	    flowEntryObj.setSwitchState("FE_SWITCH_NOT_UPDATED");
-	}
-	// Remove from the database empty flows
-	if (empty)
-	    dbHandler.removeFlowPath(flowObj);
-	dbHandler.commit();
-
-	return true;
-    }
-
-    /**
-     * Clear the state for all previously added flows.
-     *
-     * @param dbHandler the Graph Database handler to use.
-     * @return true on success, otherwise false.
-     */
-    static boolean clearAllFlows(GraphDBOperation dbHandler) {
 	List<FlowId> allFlowIds = new LinkedList<FlowId>();
 
 	// Get all Flow IDs
@@ -500,29 +393,29 @@
 	    allFlowIds.add(flowId);
 	}
 
-	// Clear all flows one-by-one
+	// Delete all flows one-by-one
 	for (FlowId flowId : allFlowIds) {
-	    clearFlow(dbHandler, flowId);
+	    deleteFlow(dbHandler, flowId);
 	}
 
 	return true;
     }
 
     /**
-     * Clear the state for a previously added flow.
+     * Delete a previously added flow.
      *
      * @param dbHandler the Graph Database handler to use.
-     * @param flowId the Flow ID of the flow to clear.
+     * @param flowId the Flow ID of the flow to delete.
      * @return true on success, otherwise false.
      */
-    static boolean clearFlow(GraphDBOperation dbHandler, FlowId flowId) {
+    static boolean deleteFlow(GraphDBOperation dbHandler, FlowId flowId) {
 	IFlowPath flowObj = null;
 	try {
 	    flowObj = dbHandler.searchFlowPath(flowId);
 	} catch (Exception e) {
 	    // TODO: handle exceptions
 	    dbHandler.rollback();
-	    log.error(":clearFlow FlowId:{} failed", flowId.toString());
+	    log.error(":deleteFlow FlowId:{} failed", flowId.toString());
 	    return false;
 	}
 	if (flowObj == null) {
@@ -706,9 +599,9 @@
      * @param maxFlows the maximum number of flows to be returned.
      * @return the Flow Paths if found, otherwise null.
      */
-    static ArrayList<IFlowPath> getAllFlowsSummary(GraphDBOperation dbHandler,
-						   FlowId flowId,
-						   int maxFlows) {
+    static ArrayList<FlowPath> getAllFlowsSummary(GraphDBOperation dbHandler,
+						  FlowId flowId,
+						  int maxFlows) {
 	//
 	// TODO: The implementation below is not optimal:
 	// We fetch all flows, and then return only the subset that match
@@ -716,61 +609,32 @@
 	// We should use the appropriate Titan/Gremlin query to filter-out
 	// the flows as appropriate.
 	//
-    	ArrayList<IFlowPath> flowPathsWithoutFlowEntries =
-	    getAllFlowsWithoutFlowEntries(dbHandler);
-
-    	Collections.sort(flowPathsWithoutFlowEntries, 
-			 new Comparator<IFlowPath>() {
-			     @Override
-			     public int compare(IFlowPath first, IFlowPath second) {
-				 long result =
-				     new FlowId(first.getFlowId()).value()
-				     - new FlowId(second.getFlowId()).value();
-				 if (result > 0) {
-				     return 1;
-				 } else if (result < 0) {
-				     return -1;
-				 } else {
-				     return 0;
-				 }
-			     }
-			 }
-			 );
-    	
-    	return flowPathsWithoutFlowEntries;
+    	ArrayList<FlowPath> flowPaths = getAllFlowsWithDataPathSummary(dbHandler);
+    	Collections.sort(flowPaths);
+    	return flowPaths;
     }
 
     /**
-     * Get all Flows information, without the associated Flow Entries.
+     * Get all Flows information, with Data Path summary for the Flow Entries.
      *
      * @param dbHandler the Graph Database handler to use.
-     * @return all Flows information, without the associated Flow Entries.
+     * @return all Flows information, with Data Path summary for the Flow
+     * Entries.
      */
-    static ArrayList<IFlowPath> getAllFlowsWithoutFlowEntries(GraphDBOperation dbHandler) {
-    	Iterable<IFlowPath> flowPathsObj = null;
-    	ArrayList<IFlowPath> flowPathsObjArray = new ArrayList<IFlowPath>();
+    static ArrayList<FlowPath> getAllFlowsWithDataPathSummary(GraphDBOperation dbHandler) {
+    	ArrayList<FlowPath> flowPaths = getAllFlows(dbHandler);
 
-	// TODO: Remove this op.commit() flow, because it is not needed?
-    	dbHandler.commit();
+	// Truncate each Flow Path and Flow Entry
+	for (FlowPath flowPath : flowPaths) {
+	    flowPath.setFlowEntryMatch(null);
+	    flowPath.setFlowEntryActions(null);
+	    for (FlowEntry flowEntry : flowPath.flowEntries()) {
+		flowEntry.setFlowEntryMatch(null);
+		flowEntry.setFlowEntryActions(null);
+	    }
+	}
 
-    	try {
-    	    flowPathsObj = dbHandler.getAllFlowPaths();
-    	} catch (Exception e) {
-    	    // TODO: handle exceptions
-    	    dbHandler.rollback();
-    	    log.error(":getAllFlowPaths failed");
-	    return flowPathsObjArray;		// No Flows found
-    	}
-    	if ((flowPathsObj == null) || (flowPathsObj.iterator().hasNext() == false)) {
-    	    return flowPathsObjArray;		// No Flows found
-    	}
-
-    	for (IFlowPath flowObj : flowPathsObj)
-	    flowPathsObjArray.add(flowObj);
-
-    	// conn.endTx(Transaction.COMMIT);
-
-    	return flowPathsObjArray;
+    	return flowPaths;
     }
 
     /**
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowEventHandler.java b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowEventHandler.java
index 0e9887a..feb80e1 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowEventHandler.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowEventHandler.java
@@ -58,9 +58,6 @@
     private FlowManager flowManager;		// The Flow Manager to use
     private IDatagridService datagridService;	// The Datagrid Service to use
     private Topology topology;			// The network topology
-    private Map<Long, FlowPath> allFlowPaths = new HashMap<Long, FlowPath>();
-    private Map<Long, FlowEntry> unmatchedFlowEntryAdd =
-	new HashMap<Long, FlowEntry>();
 
     // The queue with Flow Path and Topology Element updates
     private BlockingQueue<EventEntry<?>> networkEvents =
@@ -74,21 +71,22 @@
     private List<EventEntry<FlowEntry>> flowEntryEvents =
 	new LinkedList<EventEntry<FlowEntry>>();
 
+    // All internally computed Flow Paths
+    private Map<Long, FlowPath> allFlowPaths = new HashMap<Long, FlowPath>();
+
+    // The Flow Entries received as notifications with unmatched Flow Paths
+    private Map<Long, FlowEntry> unmatchedFlowEntryAdd =
+	new HashMap<Long, FlowEntry>();
+
     //
     // Transient state for processing the Flow Paths:
-    //  - The new Flow Paths
     //  - The Flow Paths that should be recomputed
     //  - The Flow Paths with modified Flow Entries
-    //  - The Flow Entries that were updated
     //
-    private List<FlowPath> newFlowPaths = new LinkedList<FlowPath>();
-    private List<FlowPath> recomputeFlowPaths = new LinkedList<FlowPath>();
-    private List<FlowPath> modifiedFlowPaths = new LinkedList<FlowPath>();
-    private List<FlowPathEntryPair> updatedFlowEntries =
-	new LinkedList<FlowPathEntryPair>();
-    private List<FlowPathEntryPair> unmatchedDeleteFlowEntries =
-	new LinkedList<FlowPathEntryPair>();
-
+    private Map<Long, FlowPath> shouldRecomputeFlowPaths =
+	new HashMap<Long, FlowPath>();
+    private Map<Long, FlowPath> modifiedFlowPaths =
+	new HashMap<Long, FlowPath>();
 
     /**
      * Constructor for a given Flow Manager and Datagrid Service.
@@ -171,18 +169,28 @@
 		//  - EventEntry<FlowEntry>
 		//
 		for (EventEntry<?> event : collection) {
+		    // Topology event
 		    if (event.eventData() instanceof TopologyElement) {
 			EventEntry<TopologyElement> topologyEventEntry =
 			    (EventEntry<TopologyElement>)event;
 			topologyEvents.add(topologyEventEntry);
-		    } else if (event.eventData() instanceof FlowPath) {
+			continue;
+		    }
+
+		    // FlowPath event
+		    if (event.eventData() instanceof FlowPath) {
 			EventEntry<FlowPath> flowPathEventEntry =
 			    (EventEntry<FlowPath>)event;
 			flowPathEvents.add(flowPathEventEntry);
-		    } else if (event.eventData() instanceof FlowEntry) {
+			continue;
+		    }
+
+		    // FlowEntry event
+		    if (event.eventData() instanceof FlowEntry) {
 			EventEntry<FlowEntry> flowEntryEventEntry =
 			    (EventEntry<FlowEntry>)event;
 			flowEntryEvents.add(flowEntryEventEntry);
+			continue;
 		    }
 		}
 		collection.clear();
@@ -208,22 +216,15 @@
 
 	processFlowPathEvents();
 	processTopologyEvents();
-	//
-	// Add all new Flows: should be done after processing the Flow Path
-	// and Topology events.
-	//
-	for (FlowPath flowPath : newFlowPaths) {
-	    allFlowPaths.put(flowPath.flowId().value(), flowPath);
-	}
-
 	processFlowEntryEvents();
 
 	// Recompute all affected Flow Paths and keep only the modified
-	for (FlowPath flowPath : recomputeFlowPaths) {
+	for (FlowPath flowPath : shouldRecomputeFlowPaths.values()) {
 	    if (recomputeFlowPath(flowPath))
-		modifiedFlowPaths.add(flowPath);
+		modifiedFlowPaths.put(flowPath.flowId().value(), flowPath);
 	}
 
+	// Extract the modified Flow Entries
 	modifiedFlowEntries = extractModifiedFlowEntries(modifiedFlowPaths);
 
 	// Assign missing Flow Entry IDs
@@ -234,14 +235,12 @@
 	//
 	flowManager.pushModifiedFlowEntriesToSwitches(modifiedFlowEntries);
 	flowManager.pushModifiedFlowEntriesToDatagrid(modifiedFlowEntries);
-	flowManager.pushModifiedFlowEntriesToDatabase(modifiedFlowEntries);
-	flowManager.pushModifiedFlowEntriesToDatabase(updatedFlowEntries);
-	flowManager.pushModifiedFlowEntriesToDatabase(unmatchedDeleteFlowEntries);
+	flowManager.pushModifiedFlowPathsToDatabase(modifiedFlowPaths.values());
 
 	//
 	// Remove Flow Entries that were deleted
 	//
-	for (FlowPath flowPath : modifiedFlowPaths)
+	for (FlowPath flowPath : modifiedFlowPaths.values())
 	    flowPath.dataPath().removeDeletedFlowEntries();
 
 	// Cleanup
@@ -249,23 +248,20 @@
 	flowPathEvents.clear();
 	flowEntryEvents.clear();
 	//
-	newFlowPaths.clear();
-	recomputeFlowPaths.clear();
+	shouldRecomputeFlowPaths.clear();
 	modifiedFlowPaths.clear();
-	updatedFlowEntries.clear();
-	unmatchedDeleteFlowEntries.clear();
     }
 
     /**
      * Extract the modified Flow Entries.
      */
     private List<FlowPathEntryPair> extractModifiedFlowEntries(
-					List<FlowPath> modifiedFlowPaths) {
+				Map<Long, FlowPath> modifiedFlowPaths) {
 	List<FlowPathEntryPair> modifiedFlowEntries =
 	    new LinkedList<FlowPathEntryPair>();
 
 	// Extract only the modified Flow Entries
-	for (FlowPath flowPath : modifiedFlowPaths) {
+	for (FlowPath flowPath : modifiedFlowPaths.values()) {
 	    for (FlowEntry flowEntry : flowPath.flowEntries()) {
 		if (flowEntry.flowEntrySwitchState() ==
 		    FlowEntrySwitchState.FE_SWITCH_NOT_UPDATED) {
@@ -324,10 +320,8 @@
 		if (allFlowPaths.get(flowPath.flowId().value()) != null) {
 		    //
 		    // TODO: What to do if the Flow Path already exists?
-		    // Remove and then re-add it, or merge the info?
-		    // For now, we don't have to do anything.
+		    // Fow now, we just re-add it.
 		    //
-		    break;
 		}
 
 		switch (flowPath.flowPathType()) {
@@ -337,7 +331,8 @@
 		    // we are going to recompute it anyway.
 		    //
 		    flowPath.flowEntries().clear();
-		    recomputeFlowPaths.add(flowPath);
+		    shouldRecomputeFlowPaths.put(flowPath.flowId().value(),
+						 flowPath);
 		    break;
 		case FP_TYPE_EXPLICIT_PATH:
 		    //
@@ -346,10 +341,10 @@
 		    for (FlowEntry flowEntry : flowPath.flowEntries()) {
 			flowEntry.setFlowEntrySwitchState(FlowEntrySwitchState.FE_SWITCH_NOT_UPDATED);
 		    }
-		    modifiedFlowPaths.add(flowPath);
+		    modifiedFlowPaths.put(flowPath.flowId().value(), flowPath);
 		    break;
 		}
-		newFlowPaths.add(flowPath);
+		allFlowPaths.put(flowPath.flowId().value(), flowPath);
 
 		break;
 	    }
@@ -372,8 +367,11 @@
 		    flowEntry.setFlowEntrySwitchState(FlowEntrySwitchState.FE_SWITCH_NOT_UPDATED);
 		}
 
-		allFlowPaths.remove(existingFlowPath.flowId().value());
-		modifiedFlowPaths.add(existingFlowPath);
+		// Remove the Flow Path from the internal state
+		Long key = existingFlowPath.flowId().value();
+		allFlowPaths.remove(key);
+		shouldRecomputeFlowPaths.remove(key);
+		modifiedFlowPaths.put(key, existingFlowPath);
 
 		break;
 	    }
@@ -406,7 +404,7 @@
 	}
 	if (isTopologyModified) {
 	    // TODO: For now, if the topology changes, we recompute all Flows
-	    recomputeFlowPaths.addAll(allFlowPaths.values());
+	    shouldRecomputeFlowPaths.putAll(allFlowPaths);
 	}
     }
 
@@ -434,7 +432,7 @@
 		    continue;
 		}
 		flowPair = new FlowPathEntryPair(flowPath, updatedFlowEntry);
-		updatedFlowEntries.add(flowPair);
+		modifiedFlowPaths.put(flowPath.flowId().value(), flowPath);
 	    }
 	    unmatchedFlowEntryAdd = remainingUpdates;
 	}
@@ -471,15 +469,15 @@
 		}
 		// Add the updated entry to the list of updated Flow Entries
 		flowPair = new FlowPathEntryPair(flowPath, updatedFlowEntry);
-		updatedFlowEntries.add(flowPair);
+		modifiedFlowPaths.put(flowPath.flowId().value(), flowPath);
 		break;
 
 	    case ENTRY_REMOVE:
 		flowEntry.setFlowEntryUserState(FlowEntryUserState.FE_USER_DELETE);
 		if (unmatchedFlowEntryAdd.remove(flowEntry.flowEntryId().value()) != null) {
-		    continue;		// Match found
+		    continue;		// Removed previously unmatched entry
 		}
-						 
+
 		flowPath = allFlowPaths.get(flowEntry.flowId().value());
 		if (flowPath == null) {
 		    // Flow Path not found: ignore the update
@@ -487,13 +485,11 @@
 		}
 		updatedFlowEntry = updateFlowEntryRemove(flowPath, flowEntry);
 		if (updatedFlowEntry == null) {
-		    // Flow Entry not found: add to list of deleted entries
-		    flowPair = new FlowPathEntryPair(flowPath, flowEntry);
-		    unmatchedDeleteFlowEntries.add(flowPair);
+		    // Flow Entry not found: ignore it
 		    break;
 		}
 		flowPair = new FlowPathEntryPair(flowPath, updatedFlowEntry);
-		updatedFlowEntries.add(flowPair);
+		modifiedFlowPaths.put(flowPath.flowId().value(), flowPath);
 		break;
 	    }
 	}
@@ -710,9 +706,18 @@
 	    //
 	    newFlowEntry.setFlowId(new FlowId(flowPath.flowId().value()));
 
-	    // Set the incoming port matching
-	    FlowEntryMatch flowEntryMatch = new FlowEntryMatch();
+	    //
+	    // Allocate the FlowEntryMatch by copying the default one
+	    // from the FlowPath (if set).
+	    //
+	    FlowEntryMatch flowEntryMatch = null;
+	    if (flowPath.flowEntryMatch() != null)
+		flowEntryMatch = new FlowEntryMatch(flowPath.flowEntryMatch());
+	    else
+		flowEntryMatch = new FlowEntryMatch();
 	    newFlowEntry.setFlowEntryMatch(flowEntryMatch);
+
+	    // Set the incoming port matching
 	    flowEntryMatch.enableInPort(newFlowEntry.inPort());
 
 	    //
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowManager.java b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowManager.java
index 174d5d7..7f43fe9 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowManager.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowManager.java
@@ -2,12 +2,12 @@
 
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.EnumSet;
 import java.util.HashMap;
 import java.util.LinkedList;
 import java.util.Map;
 import java.util.Random;
-import java.util.concurrent.Executors;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
 
@@ -18,7 +18,6 @@
 import net.floodlightcontroller.core.module.IFloodlightModule;
 import net.floodlightcontroller.core.module.IFloodlightService;
 import net.floodlightcontroller.restserver.IRestApiService;
-import net.floodlightcontroller.util.OFMessageDamper;
 import net.onrc.onos.datagrid.IDatagridService;
 import net.onrc.onos.graph.GraphDBOperation;
 import net.onrc.onos.ofcontroller.core.INetMapStorage;
@@ -27,7 +26,6 @@
 import net.onrc.onos.ofcontroller.floodlightlistener.INetworkGraphService;
 import net.onrc.onos.ofcontroller.flowmanager.web.FlowWebRoutable;
 import net.onrc.onos.ofcontroller.flowprogrammer.IFlowPusherService;
-import net.onrc.onos.ofcontroller.topology.ITopologyNetService;
 import net.onrc.onos.ofcontroller.topology.Topology;
 import net.onrc.onos.ofcontroller.util.*;
 
@@ -39,21 +37,10 @@
  * Flow Manager class for handling the network flows.
  */
 public class FlowManager implements IFloodlightModule, IFlowService, INetMapStorage {
-
-    //
-    // TODO: A temporary variable to switch between the poll-based and
-    // notification mechanism for the Flow Manager.
-    //
-    private final static boolean enableNotifications = true;
-    
-    // flag to use FlowPusher instead of FlowSwitchOperation/MessageDamper
-    private final static boolean enableFlowPusher = false;
-
     protected GraphDBOperation dbHandlerApi;
     protected GraphDBOperation dbHandlerInner;
 
     protected volatile IFloodlightProviderService floodlightProvider;
-    protected volatile ITopologyNetService topologyNetService;
     protected volatile IDatagridService datagridService;
     protected IRestApiService restApi;
     protected FloodlightModuleContext context;
@@ -61,322 +48,18 @@
 
     protected IFlowPusherService pusher;
     
-    protected OFMessageDamper messageDamper;
-    
-    //
-    // TODO: Values copied from elsewhere (class LearningSwitch).
-    // The local copy should go away!
-    //
-    protected static final int OFMESSAGE_DAMPER_CAPACITY = 50000; // TODO: find sweet spot
-    protected static final int OFMESSAGE_DAMPER_TIMEOUT = 250;	// ms
-
     // Flow Entry ID generation state
     private static Random randomGenerator = new Random();
     private static int nextFlowEntryIdPrefix = 0;
     private static int nextFlowEntryIdSuffix = 0;
-    private static long nextFlowEntryId = 0;
 
     /** The logger. */
     private final static Logger log = LoggerFactory.getLogger(FlowManager.class);
 
-    // The periodic task(s)
-    private ScheduledExecutorService mapReaderScheduler;
-    private ScheduledExecutorService shortestPathReconcileScheduler;
-
-    /**
-     * Periodic task for reading the Flow Entries and pushing changes
-     * into the switches.
-     */
-    final Runnable mapReader = new Runnable() {
-	    public void run() {
-		try {
-		    runImpl();
-		} catch (Exception e) {
-		    log.debug("Exception processing All Flow Entries from the Network MAP: ", e);
-		    dbHandlerInner.rollback();
-		    return;
-		}
-	    }
-
-	    private void runImpl() {
-		long startTime = System.nanoTime();
-		int counterAllFlowEntries = 0;
-		int counterMyNotUpdatedFlowEntries = 0;
-
-		if (floodlightProvider == null) {
-		    log.debug("FloodlightProvider service not found!");
-		    return;
-		}
-		Map<Long, IOFSwitch> mySwitches =
-		    floodlightProvider.getSwitches();
-		if (mySwitches.isEmpty()) {
-			log.trace("No switches controlled");
-			return;
-		}
-		LinkedList<IFlowEntry> addFlowEntries =
-		    new LinkedList<IFlowEntry>();
-		LinkedList<IFlowEntry> deleteFlowEntries =
-		    new LinkedList<IFlowEntry>();
-
-		//
-		// Fetch all Flow Entries which need to be updated and select
-		// only my Flow Entries that need to be updated into the
-		// switches.
-		//
-		Iterable<IFlowEntry> allFlowEntries =
-		    dbHandlerInner.getAllSwitchNotUpdatedFlowEntries();
-		for (IFlowEntry flowEntryObj : allFlowEntries) {
-			log.debug("flowEntryobj : {}", flowEntryObj);
-			
-		    counterAllFlowEntries++;
-
-		    String dpidStr = flowEntryObj.getSwitchDpid();
-		    if (dpidStr == null)
-			continue;
-		    Dpid dpid = new Dpid(dpidStr);
-		    IOFSwitch mySwitch = mySwitches.get(dpid.value());
-		    if (mySwitch == null)
-			continue;	// Ignore the entry: not my switch
-
-		    IFlowPath flowObj =
-			dbHandlerInner.getFlowPathByFlowEntry(flowEntryObj);
-		    if (flowObj == null)
-			continue;		// Should NOT happen
-		    if (flowObj.getFlowId() == null)
-			continue;		// Invalid entry
-
-		    //
-		    // NOTE: For now we process the DELETE before the ADD
-		    // to cover the more common scenario.
-		    // TODO: This is error prone and needs to be fixed!
-		    //
-		    String userState = flowEntryObj.getUserState();
-		    if (userState == null)
-			continue;
-		    if (userState.equals("FE_USER_DELETE")) {
-			// An entry that needs to be deleted.
-			deleteFlowEntries.add(flowEntryObj);
-			installFlowEntry(mySwitch, flowObj, flowEntryObj);
-		    } else {
-			addFlowEntries.add(flowEntryObj);
-		    }
-		    counterMyNotUpdatedFlowEntries++;
-		}
-		
-		log.debug("addFlowEntries : {}", addFlowEntries);
-
-		//
-		// Process the Flow Entries that need to be added
-		//
-		for (IFlowEntry flowEntryObj : addFlowEntries) {
-		    IFlowPath flowObj =
-			dbHandlerInner.getFlowPathByFlowEntry(flowEntryObj);
-		    if (flowObj == null)
-			continue;		// Should NOT happen
-		    if (flowObj.getFlowId() == null)
-			continue;		// Invalid entry
-
-		    Dpid dpid = new Dpid(flowEntryObj.getSwitchDpid());
-		    IOFSwitch mySwitch = mySwitches.get(dpid.value());
-		    if (mySwitch == null)
-			continue;		// Shouldn't happen
-		    installFlowEntry(mySwitch, flowObj, flowEntryObj);
-		}
-
-		//
-		// Delete all Flow Entries marked for deletion from the
-		// Network MAP.
-		//
-		// TODO: We should use the OpenFlow Barrier mechanism
-		// to check for errors, and delete the Flow Entries after the
-		// Barrier message is received.
-		//
-		while (! deleteFlowEntries.isEmpty()) {
-		    IFlowEntry flowEntryObj = deleteFlowEntries.poll();
-		    IFlowPath flowObj =
-			dbHandlerInner.getFlowPathByFlowEntry(flowEntryObj);
-		    if (flowObj == null) {
-			log.debug("Did not find FlowPath to be deleted");
-			continue;
-		    }
-		    flowObj.removeFlowEntry(flowEntryObj);
-		    dbHandlerInner.removeFlowEntry(flowEntryObj);
-		}
-
-		dbHandlerInner.commit();
-
-		long estimatedTime = System.nanoTime() - startTime;
-		double rate = 0.0;
-		if (estimatedTime > 0)
-		    rate = ((double)counterAllFlowEntries * 1000000000) / estimatedTime;
-		String logMsg = "MEASUREMENT: Processed AllFlowEntries: " +
-		    counterAllFlowEntries + " MyNotUpdatedFlowEntries: " +
-		    counterMyNotUpdatedFlowEntries + " in " +
-		    (double)estimatedTime / 1000000000 + " sec: " +
-		    rate + " paths/s";
-		log.debug(logMsg);
-	    }
-	};
-
-    /**
-     * Periodic task for reading the Flow Paths and recomputing the
-     * shortest paths.
-     */
-    final Runnable shortestPathReconcile = new Runnable() {
-	    public void run() {
-		try {
-		    runImpl();
-		} catch (Exception e) {
-		    log.debug("Exception processing All Flows from the Network MAP: ", e);
-		    dbHandlerInner.rollback();
-		    return;
-		}
-	    }
-
-	    private void runImpl() {
-		long startTime = System.nanoTime();
-		int counterAllFlowPaths = 0;
-		int counterMyFlowPaths = 0;
-
-		if (floodlightProvider == null) {
-		    log.debug("FloodlightProvider service not found!");
-		    return;
-		}
-		Map<Long, IOFSwitch> mySwitches =
-		    floodlightProvider.getSwitches();
-		if (mySwitches.isEmpty()) {
-			log.trace("No switches controlled");
-			return;
-		}
-		LinkedList<IFlowPath> deleteFlows = new LinkedList<IFlowPath>();
-
-		//
-		// Fetch and recompute the Shortest Path for those
-		// Flow Paths this controller is responsible for.
-		//
-		Topology topology = topologyNetService.newDatabaseTopology();
-		Iterable<IFlowPath> allFlowPaths = dbHandlerInner.getAllFlowPaths();
-		for (IFlowPath flowPathObj : allFlowPaths) {
-		    counterAllFlowPaths++;
-		    if (flowPathObj == null)
-			continue;
-
-		    String srcDpidStr = flowPathObj.getSrcSwitch();
-		    if (srcDpidStr == null)
-			continue;
-		    Dpid srcDpid = new Dpid(srcDpidStr);
-		    //
-		    // Use the source DPID as a heuristic to decide
-		    // which controller is responsible for maintaining the
-		    // shortest path.
-		    // NOTE: This heuristic is error-prone: if the switch
-		    // goes away and no controller is responsible for that
-		    // switch, then the original Flow Path is not cleaned-up
-		    //
-		    IOFSwitch mySwitch = mySwitches.get(srcDpid.value());
-		    if (mySwitch == null)
-			continue;	// Ignore: not my responsibility
-
-		    // Test whether we need to maintain this flow
-		    String flowPathTypeStr = flowPathObj.getFlowPathType();
-		    if (flowPathTypeStr == null)
-			continue;	// Could be invalid entry?
-		    if (! flowPathTypeStr.equals("FP_TYPE_SHORTEST_PATH"))
-			continue;	// No need to maintain this flow
-
-		    //
-		    // Test whether we need to complete the Flow cleanup,
-		    // if the Flow has been deleted by the user.
-		    //
-		    String flowPathUserStateStr = flowPathObj.getFlowPathUserState();
-		    if ((flowPathUserStateStr != null)
-			&& flowPathUserStateStr.equals("FP_USER_DELETE")) {
-			Iterable<IFlowEntry> flowEntries = flowPathObj.getFlowEntries();
-			final boolean empty = !flowEntries.iterator().hasNext();
-			if (empty)
-			    deleteFlows.add(flowPathObj);
-		    }
-
-		    // Fetch the fields needed to recompute the shortest path
-		    String dataPathSummaryStr = flowPathObj.getDataPathSummary();
-		    Short srcPortShort = flowPathObj.getSrcPort();
-		    String dstDpidStr = flowPathObj.getDstSwitch();
-		    Short dstPortShort = flowPathObj.getDstPort();
-		    Long flowPathFlagsLong = flowPathObj.getFlowPathFlags();
-		    if ((dataPathSummaryStr == null) ||
-			(srcPortShort == null) ||
-			(dstDpidStr == null) ||
-			(dstPortShort == null) ||
-			(flowPathFlagsLong == null)) {
-			continue;
-		    }
-
-		    Port srcPort = new Port(srcPortShort);
-		    Dpid dstDpid = new Dpid(dstDpidStr);
-		    Port dstPort = new Port(dstPortShort);
-		    SwitchPort srcSwitchPort = new SwitchPort(srcDpid, srcPort);
-		    SwitchPort dstSwitchPort = new SwitchPort(dstDpid, dstPort);
-		    FlowPathType flowPathType = FlowPathType.valueOf(flowPathTypeStr);
-		    FlowPathUserState flowPathUserState = FlowPathUserState.valueOf(flowPathUserStateStr);
-		    FlowPathFlags flowPathFlags = new FlowPathFlags(flowPathFlagsLong);
-
-		    counterMyFlowPaths++;
-
-		    //
-		    // NOTE: Using here the regular getDatabaseShortestPath()
-		    // method won't work here, because that method calls
-		    // internally "conn.endTx(Transaction.COMMIT)", and that
-		    // will invalidate all handlers to the Titan database.
-		    // If we want to experiment with calling here
-		    // getDatabaseShortestPath(), we need to refactor that code
-		    // to avoid closing the transaction.
-		    //
-		    DataPath dataPath =
-			topologyNetService.getTopologyShortestPath(
-				topology,
-				srcSwitchPort,
-				dstSwitchPort);
-		    if (dataPath == null) {
-			// We need the DataPath to compare the paths
-			dataPath = new DataPath();
-			dataPath.setSrcPort(srcSwitchPort);
-			dataPath.setDstPort(dstSwitchPort);
-		    }
-		    dataPath.applyFlowPathFlags(flowPathFlags);
-
-		    String newDataPathSummaryStr = dataPath.dataPathSummary();
-		    if (dataPathSummaryStr.equals(newDataPathSummaryStr))
-			continue;	// Nothing changed
-
-		    reconcileFlow(flowPathObj, dataPath);
-		}
-
-		//
-		// Delete all leftover Flows marked for deletion from the
-		// Network MAP.
-		//
-		while (! deleteFlows.isEmpty()) {
-		    IFlowPath flowPathObj = deleteFlows.poll();
-		    dbHandlerInner.removeFlowPath(flowPathObj);
-		}
-
-		topologyNetService.dropTopology(topology);
-
-		dbHandlerInner.commit();
-
-		long estimatedTime = System.nanoTime() - startTime;
-		double rate = 0.0;
-		if (estimatedTime > 0)
-		    rate = ((double)counterAllFlowPaths * 1000000000) / estimatedTime;
-		String logMsg = "MEASUREMENT: Processed AllFlowPaths: " +
-		    counterAllFlowPaths + " MyFlowPaths: " +
-		    counterMyFlowPaths + " in " +
-		    (double)estimatedTime / 1000000000 + " sec: " +
-		    rate + " paths/s";
-		log.debug(logMsg);
-	    }
-	};
-
+    // The queue to write Flow Entries to the database
+    private BlockingQueue<FlowPath> flowPathsToDatabaseQueue =
+	new LinkedBlockingQueue<FlowPath>();
+    FlowDatabaseWriter flowDatabaseWriter;
 
     /**
      * Initialize the Flow Manager.
@@ -462,22 +145,11 @@
 	throws FloodlightModuleException {
 	this.context = context;
 	floodlightProvider = context.getServiceImpl(IFloodlightProviderService.class);
-	topologyNetService = context.getServiceImpl(ITopologyNetService.class);
 	datagridService = context.getServiceImpl(IDatagridService.class);
 	restApi = context.getServiceImpl(IRestApiService.class);
-
-	if (enableFlowPusher) {
-		pusher = context.getServiceImpl(IFlowPusherService.class);
-	} else {
-		messageDamper = new OFMessageDamper(OFMESSAGE_DAMPER_CAPACITY,
-	    EnumSet.of(OFType.FLOW_MOD),
-	    OFMESSAGE_DAMPER_TIMEOUT);
-	}
+	pusher = context.getServiceImpl(IFlowPusherService.class);
 
 	this.init("");
-
-	mapReaderScheduler = Executors.newScheduledThreadPool(1);
-	shortestPathReconcileScheduler = Executors.newScheduledThreadPool(1);
     }
 
     /**
@@ -515,22 +187,23 @@
 
 	// Initialize the Flow Entry ID generator
 	nextFlowEntryIdPrefix = randomGenerator.nextInt();
-	
+
 	//
-	// Create the Flow Event Handler thread and register it with the
-	// Datagrid Service
+	// The thread to write to the database
+	//
+	flowDatabaseWriter = new FlowDatabaseWriter(this,
+						flowPathsToDatabaseQueue);
+	flowDatabaseWriter.start();
+
+	//
+	// The Flow Event Handler thread:
+	//  - create
+	//  - register with the Datagrid Service
+	//  - startup
 	//
 	flowEventHandler = new FlowEventHandler(this, datagridService);
 	datagridService.registerFlowEventHandlerService(flowEventHandler);
-
-	// Schedule the threads and periodic tasks
 	flowEventHandler.start();
-	if (! enableNotifications) {
-	    mapReaderScheduler.scheduleAtFixedRate(
-			mapReader, 3, 3, TimeUnit.SECONDS);
-	    shortestPathReconcileScheduler.scheduleAtFixedRate(
-			shortestPathReconcile, 3, 3, TimeUnit.SECONDS);
-	}
     }
 
     /**
@@ -593,19 +266,11 @@
      */
     @Override
     public boolean deleteAllFlows() {
-	//
-	// TODO: In the notification-based implementation,
-	// deleteFlow() is implemented by using clearFlow()
-	//
-	return clearAllFlows();
-
-	/*
 	if (FlowDatabaseOperation.deleteAllFlows(dbHandlerApi)) {
 	    datagridService.notificationSendAllFlowsRemoved();
 	    return true;
 	}
 	return false;
-	*/
     }
 
     /**
@@ -616,47 +281,11 @@
      */
     @Override
     public boolean deleteFlow(FlowId flowId) {
-	//
-	// TODO: In the notification-based implementation,
-	// deleteFlow() is implemented by using clearFlow()
-	//
-	return clearFlow(flowId);
-	/*
 	if (FlowDatabaseOperation.deleteFlow(dbHandlerApi, flowId)) {
 	    datagridService.notificationSendFlowRemoved(flowId);
 	    return true;
 	}
 	return false;
-	*/
-    }
-
-    /**
-     * Clear the state for all previously added flows.
-     *
-     * @return true on success, otherwise false.
-     */
-    @Override
-    public boolean clearAllFlows() {
-	if (FlowDatabaseOperation.clearAllFlows(dbHandlerApi)) {
-	    datagridService.notificationSendAllFlowsRemoved();
-	    return true;
-	}
-	return false;
-    }
-
-    /**
-     * Clear the state for a previously added flow.
-     *
-     * @param flowId the Flow ID of the flow to clear.
-     * @return true on success, otherwise false.
-     */
-    @Override
-    public boolean clearFlow(FlowId flowId) {
-	if (FlowDatabaseOperation.clearFlow(dbHandlerApi, flowId)) {
-	    datagridService.notificationSendFlowRemoved(flowId);
-	    return true;
-	}
-	return false;
     }
 
     /**
@@ -715,22 +344,13 @@
      * @return the Flow Paths if found, otherwise null.
      */
     @Override
-    public ArrayList<IFlowPath> getAllFlowsSummary(FlowId flowId,
-						   int maxFlows) {
+    public ArrayList<FlowPath> getAllFlowsSummary(FlowId flowId,
+						  int maxFlows) {
 	return FlowDatabaseOperation.getAllFlowsSummary(dbHandlerApi, flowId,
 							maxFlows);
     }
     
     /**
-     * Get all Flows information, without the associated Flow Entries.
-     *
-     * @return all Flows information, without the associated Flow Entries.
-     */
-    public ArrayList<IFlowPath> getAllFlowsWithoutFlowEntries() {
-	return FlowDatabaseOperation.getAllFlowsWithoutFlowEntries(dbHandlerApi);
-    }
-
-    /**
      * Add and maintain a shortest-path flow.
      *
      * NOTE: The Flow Path argument does NOT contain flow entries.
@@ -772,139 +392,13 @@
     }
 
     /**
-     * Reconcile a flow.
+     * Inform the Flow Manager that a Flow Entry on switch expired.
      *
-     * @param flowObj the flow that needs to be reconciled.
-     * @param newDataPath the new data path to use.
-     * @return true on success, otherwise false.
+     * @param sw the switch the Flow Entry expired on.
+     * @param flowEntryId the Flow Entry ID of the expired Flow Entry.
      */
-    private boolean reconcileFlow(IFlowPath flowObj, DataPath newDataPath) {
-	String flowIdStr = flowObj.getFlowId();
-
-	//
-	// Set the incoming port matching and the outgoing port output
-	// actions for each flow entry.
-	//
-	int idx = 0;
-	for (FlowEntry flowEntry : newDataPath.flowEntries()) {
-	    flowEntry.setFlowId(new FlowId(flowIdStr));
-
-	    // Mark the Flow Entry as not updated in the switch
-	    flowEntry.setFlowEntrySwitchState(FlowEntrySwitchState.FE_SWITCH_NOT_UPDATED);
-	    // Set the incoming port matching
-	    FlowEntryMatch flowEntryMatch = new FlowEntryMatch();
-	    flowEntry.setFlowEntryMatch(flowEntryMatch);
-	    flowEntryMatch.enableInPort(flowEntry.inPort());
-
-	    //
-	    // Set the actions
-	    //
-	    FlowEntryActions flowEntryActions = flowEntry.flowEntryActions();
-	    //
-	    // If the first Flow Entry, copy the Flow Path actions to it
-	    //
-	    if (idx == 0) {
-		String actionsStr = flowObj.getActions();
-		if (actionsStr != null) {
-		    FlowEntryActions flowActions = new FlowEntryActions(actionsStr);
-		    for (FlowEntryAction action : flowActions.actions())
-			flowEntryActions.addAction(action);
-		}
-	    }
-	    idx++;
-	    //
-	    // Add the outgoing port output action
-	    //
-	    FlowEntryAction flowEntryAction = new FlowEntryAction();
-	    flowEntryAction.setActionOutput(flowEntry.outPort());
-	    flowEntryActions.addAction(flowEntryAction);
-	}
-
-	//
-	// Remove the old Flow Entries, and add the new Flow Entries
-	//
-	Iterable<IFlowEntry> flowEntries = flowObj.getFlowEntries();
-	for (IFlowEntry flowEntryObj : flowEntries) {
-	    flowEntryObj.setUserState("FE_USER_DELETE");
-	    flowEntryObj.setSwitchState("FE_SWITCH_NOT_UPDATED");
-	}
-	for (FlowEntry flowEntry : newDataPath.flowEntries()) {
-	    addFlowEntry(flowObj, flowEntry);
-	}
-
-	//
-	// Set the Data Path Summary
-	//
-	String dataPathSummaryStr = newDataPath.dataPathSummary();
-	flowObj.setDataPathSummary(dataPathSummaryStr);
-
-	return true;
-    }
-
-    /**
-     * Reconcile all flows in a set.
-     *
-     * @param flowObjSet the set of flows that need to be reconciliated.
-     */
-    private void reconcileFlows(Iterable<IFlowPath> flowObjSet) {
-	if (! flowObjSet.iterator().hasNext())
-	    return;
-	// TODO: Not implemented/used yet.
-    }
-
-    /**
-     * Install a Flow Entry on a switch.
-     *
-     * @param mySwitch the switch to install the Flow Entry into.
-     * @param flowObj the flow path object for the flow entry to install.
-     * @param flowEntryObj the flow entry object to install.
-     * @return true on success, otherwise false.
-     */
-    private boolean installFlowEntry(IOFSwitch mySwitch, IFlowPath flowObj,
-				    IFlowEntry flowEntryObj) {
-    	if (enableFlowPusher) {
-        	return pusher.add(mySwitch, flowObj, flowEntryObj);
-    	} else {
-    		return FlowSwitchOperation.installFlowEntry(
-    			floodlightProvider.getOFMessageFactory(),
-    			messageDamper, mySwitch, flowObj, flowEntryObj);
-    	}
-    }
-
-    /**
-     * Install a Flow Entry on a switch.
-     *
-     * @param mySwitch the switch to install the Flow Entry into.
-     * @param flowPath the flow path for the flow entry to install.
-     * @param flowEntry the flow entry to install.
-     * @return true on success, otherwise false.
-     */
-    private boolean installFlowEntry(IOFSwitch mySwitch, FlowPath flowPath,
-				    FlowEntry flowEntry) {
-    	if (enableFlowPusher) {
-        	return pusher.add(mySwitch, flowPath, flowEntry);
-    	} else {
-    		return FlowSwitchOperation.installFlowEntry(
-    		floodlightProvider.getOFMessageFactory(),
-    		messageDamper, mySwitch, flowPath, flowEntry);
-    	}
-    }
-
-    /**
-     * Remove a Flow Entry from a switch.
-     *
-     * @param mySwitch the switch to remove the Flow Entry from.
-     * @param flowPath the flow path for the flow entry to remove.
-     * @param flowEntry the flow entry to remove.
-     * @return true on success, otherwise false.
-     */
-    private boolean removeFlowEntry(IOFSwitch mySwitch, FlowPath flowPath,
-				   FlowEntry flowEntry) {
-	//
-	// The installFlowEntry() method implements both installation
-	// and removal of flow entries.
-	//
-	return (installFlowEntry(mySwitch, flowPath, flowEntry));
+    public void flowEntryOnSwitchExpired(IOFSwitch sw, FlowEntryId flowEntryId) {
+	// TODO: Not implemented yet
     }
 
     /**
@@ -917,17 +411,12 @@
      */
     public void pushModifiedFlowEntriesToSwitches(
 			Collection<FlowPathEntryPair> modifiedFlowEntries) {
-	// TODO: For now, the pushing of Flow Entries is disabled
-	if (! enableNotifications)
-	    return;
-
 	if (modifiedFlowEntries.isEmpty())
 	    return;
 
 	Map<Long, IOFSwitch> mySwitches = getMySwitches();
 
 	for (FlowPathEntryPair flowPair : modifiedFlowEntries) {
-	    FlowPath flowPath = flowPair.flowPath;
 	    FlowEntry flowEntry = flowPair.flowEntry;
 
 	    IOFSwitch mySwitch = mySwitches.get(flowEntry.dpid().value());
@@ -937,12 +426,12 @@
 	    log.debug("Pushing Flow Entry To Switch: {}", flowEntry.toString());
 
 	    //
-	    // Install the Flow Entry into the switch
+	    // Push the Flow Entry into the switch
 	    //
-	    if (! installFlowEntry(mySwitch, flowPath, flowEntry)) {
+	    if (! pusher.add(mySwitch, flowEntry)) {
 		String logMsg = "Cannot install Flow Entry " +
 		    flowEntry.flowEntryId() +
-		    " from Flow Path " + flowPath.flowId() +
+		    " from Flow Path " + flowEntry.flowId() +
 		    " on switch " + flowEntry.dpid();
 		log.error(logMsg);
 		continue;
@@ -963,10 +452,6 @@
      */
     public void pushModifiedFlowEntriesToDatagrid(
 			Collection<FlowPathEntryPair> modifiedFlowEntries) {
-	// TODO: For now, the pushing of Flow Entries is disabled
-	if (! enableNotifications)
-	    return;
-
 	if (modifiedFlowEntries.isEmpty())
 	    return;
 
@@ -975,6 +460,9 @@
 	for (FlowPathEntryPair flowPair : modifiedFlowEntries) {
 	    FlowEntry flowEntry = flowPair.flowEntry;
 
+	    if (! flowEntry.isValidFlowEntryId())
+		continue;
+
 	    IOFSwitch mySwitch = mySwitches.get(flowEntry.dpid().value());
 
 	    //
@@ -993,8 +481,6 @@
 		    FlowEntryUserState.FE_USER_DELETE) {
 		    continue;
 		}
-		if (! flowEntry.isValidFlowEntryId())
-		    continue;
 	    }
 
 	    log.debug("Pushing Flow Entry To Datagrid: {}", flowEntry.toString());
@@ -1020,32 +506,84 @@
     }
 
     /**
-     * Push Flow Entries to the Network MAP.
-     *
-     * NOTE: The Flow Entries are pushed only on the instance responsible
-     * for the first switch. This is to avoid database errors when multiple
-     * instances are writing Flow Entries for the same Flow Path.
-     *
-     * @param modifiedFlowEntries the collection of Flow Entries to push.
+     * Class to implement writing to the database in a separate thread.
      */
-    public void pushModifiedFlowEntriesToDatabase(
-		Collection<FlowPathEntryPair> modifiedFlowEntries) {
-	// TODO: For now, the pushing of Flow Entries is disabled
-	if (! enableNotifications)
+    class FlowDatabaseWriter extends Thread {
+	private FlowManager flowManager;
+	private BlockingQueue<FlowPath> blockingQueue;
+
+	/**
+	 * Constructor.
+	 *
+	 * @param flowManager the Flow Manager to use.
+	 * @param blockingQueue the blocking queue to use.
+	 */
+	FlowDatabaseWriter(FlowManager flowManager,
+			   BlockingQueue<FlowPath> blockingQueue) {
+	    this.flowManager = flowManager;
+	    this.blockingQueue = blockingQueue;
+	}
+
+	/**
+	 * Run the thread.
+	 */
+	@Override
+	public void run() {
+	    //
+	    // The main loop
+	    //
+	    Collection<FlowPath> collection = new LinkedList<FlowPath>();
+	    try {
+		while (true) {
+		    FlowPath flowPath = blockingQueue.take();
+		    collection.add(flowPath);
+		    blockingQueue.drainTo(collection);
+		    flowManager.writeModifiedFlowPathsToDatabase(collection);
+		    collection.clear();
+		}
+	    } catch (Exception exception) {
+		log.debug("Exception writing to the Database: ", exception);
+	    }
+	}
+    }
+
+    /**
+     * Push Flow Paths to the Network MAP.
+     *
+     * NOTE: The complete Flow Paths are pushed only on the instance
+     * responsible for the first switch. This is to avoid database errors
+     * when multiple instances are writing Flow Entries for the same Flow Path.
+     *
+     * @param modifiedFlowPaths the collection of Flow Paths to push.
+     */
+    void pushModifiedFlowPathsToDatabase(
+		Collection<FlowPath> modifiedFlowPaths) {
+	//
+	// We only add the Flow Paths to the Database Queue.
+	// The FlowDatabaseWriter thread is responsible for the actual writing.
+	//
+	flowPathsToDatabaseQueue.addAll(modifiedFlowPaths);
+    }
+
+    /**
+     * Write Flow Paths to the Network MAP.
+     *
+     * NOTE: The complete Flow Paths are pushed only on the instance
+     * responsible for the first switch. This is to avoid database errors
+     * when multiple instances are writing Flow Entries for the same Flow Path.
+     *
+     * @param modifiedFlowPaths the collection of Flow Paths to write.
+     */
+    private void writeModifiedFlowPathsToDatabase(
+		Collection<FlowPath> modifiedFlowPaths) {
+	if (modifiedFlowPaths.isEmpty())
 	    return;
 
-	if (modifiedFlowEntries.isEmpty())
-	    return;
+	FlowId dummyFlowId = new FlowId();
 
 	Map<Long, IOFSwitch> mySwitches = getMySwitches();
 
-	for (FlowPathEntryPair flowPair : modifiedFlowEntries) {
-	    FlowPath flowPath = flowPair.flowPath;
-	    FlowEntry flowEntry = flowPair.flowEntry;
-
-	    if (! flowEntry.isValidFlowEntryId())
-		continue;
-
+	for (FlowPath flowPath : modifiedFlowPaths) {
 	    //
 	    // Push the changes only on the instance responsible for the
 	    // first switch.
@@ -1055,69 +593,37 @@
 	    if (mySrcSwitch == null)
 		continue;
 
-	    log.debug("Pushing Flow Entry To Database: {}", flowEntry.toString());
 	    //
-	    // Write the Flow Entry to the Network Map
+	    // Test whether all Flow Entries are valid
 	    //
-	    // NOTE: We try a number of times, in case somehow some other
-	    // instances are writing at the same time.
-	    // Apparently, if other instances are writing at the same time
-	    // this will trigger an error.
-	    //
-	    for (int i = 0; i < 6; i++) {
-		try {
-		    //
-		    // Find the Flow Path in the Network MAP.
-		    //
-		    // NOTE: The Flow Path might not be found if the Flow was
-		    // just removed by some other controller instance.
-		    //
-		    IFlowPath flowObj =
-			dbHandlerInner.searchFlowPath(flowEntry.flowId());
-		    if (flowObj == null) {
-			String logMsg = "Cannot find Network MAP entry for Flow Path " + flowEntry.flowId();
-			log.error(logMsg);
-			break;
-		    }
-
-		    // Write the Flow Entry
-		    switch (flowEntry.flowEntryUserState()) {
-		    case FE_USER_ADD:
-			// FALLTHROUGH
-		    case FE_USER_MODIFY:
-			if (addFlowEntry(flowObj, flowEntry) == null) {
-			    String logMsg = "Cannot write to Network MAP Flow Entry " +
-				flowEntry.flowEntryId() +
-				" from Flow Path " + flowEntry.flowId() +
-				" on switch " + flowEntry.dpid();
-			    log.error(logMsg);
-			}
-			break;
-		    case FE_USER_DELETE:
-			if (deleteFlowEntry(flowObj, flowEntry) == false) {
-			    String logMsg = "Cannot remove from Network MAP Flow Entry " +
-				flowEntry.flowEntryId() +
-				" from Flow Path " + flowEntry.flowId() +
-				" on switch " + flowEntry.dpid();
-			    log.error(logMsg);
-			}
-			break;
-		    }
-
-		    // Commit to the database
-		    dbHandlerInner.commit();
-		    break;	// Success
-
-		} catch (Exception e) {
-		    log.debug("Exception writing Flow Entry to Network MAP: ", e);
-		    dbHandlerInner.rollback();
-		    // Wait a bit (random value [1ms, 20ms] and try again
-		    int delay = 1 + randomGenerator.nextInt() % 20;
-		    try {
-			Thread.sleep(delay);
-		    } catch (Exception e0) {
-		    }
+	    boolean allValid = true;
+	    for (FlowEntry flowEntry : flowPath.flowEntries()) {
+		if (flowEntry.flowEntryUserState() ==
+		    FlowEntryUserState.FE_USER_DELETE) {
+		    continue;
 		}
+		if (! flowEntry.isValidFlowEntryId()) {
+		    allValid = false;
+		    break;
+		}
+	    }
+	    if (! allValid)
+		continue;
+
+	    log.debug("Pushing Flow Path To Database: {}", flowPath.toString());
+
+	    //
+	    // Write the Flow Path to the Network Map
+	    //
+	    try {
+		if (! FlowDatabaseOperation.addFlow(this, dbHandlerInner,
+						    flowPath, dummyFlowId)) {
+		    String logMsg = "Cannot write to Network Map Flow Path " +
+			flowPath.flowId();
+		    log.error(logMsg);
+		}
+	    } catch (Exception e) {
+		log.error("Exception writing Flow Path to Network MAP: ", e);
 	    }
 	}
     }
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowSwitchOperation.java b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowSwitchOperation.java
deleted file mode 100644
index 8bed120..0000000
--- a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowSwitchOperation.java
+++ /dev/null
@@ -1,689 +0,0 @@
-package net.onrc.onos.ofcontroller.flowmanager;
-
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.List;
-
-import net.floodlightcontroller.core.IOFSwitch;
-import net.floodlightcontroller.util.MACAddress;
-import net.floodlightcontroller.util.OFMessageDamper;
-
-import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IFlowEntry;
-import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IFlowPath;
-import net.onrc.onos.ofcontroller.util.*;
-import net.onrc.onos.ofcontroller.util.FlowEntryAction.*;
-
-import org.openflow.protocol.OFFlowMod;
-import org.openflow.protocol.OFMatch;
-import org.openflow.protocol.OFPacketOut;
-import org.openflow.protocol.OFPort;
-import org.openflow.protocol.OFType;
-import org.openflow.protocol.action.*;
-import org.openflow.protocol.factory.BasicFactory;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-/**
- * Class for performing Flow-related operations on the Switch.
- */
-class FlowSwitchOperation {
-    private final static Logger log = LoggerFactory.getLogger(FlowSwitchOperation.class);
-    //
-    // TODO: Values copied from elsewhere (class LearningSwitch).
-    // The local copy should go away!
-    //
-    public static final short PRIORITY_DEFAULT = 100;
-    public static final short FLOWMOD_DEFAULT_IDLE_TIMEOUT = 0;	// infinity
-    public static final short FLOWMOD_DEFAULT_HARD_TIMEOUT = 0;	// infinite
-
-    // TODO add Pusher instance member
-    // 
-    
-    /**
-     * Install a Flow Entry on a switch.
-     *
-     * @param messageFactory the OpenFlow message factory to use.
-     * @param messageDamper the OpenFlow message damper to use.
-     * @param mySwitch the switch to install the Flow Entry into.
-     * @param flowObj the flow path object for the flow entry to install.
-     * @param flowEntryObj the flow entry object to install.
-     * @return true on success, otherwise false.
-     */
-    static boolean installFlowEntry(BasicFactory messageFactory,
-				    OFMessageDamper messageDamper,
-				    IOFSwitch mySwitch, IFlowPath flowObj,
-				    IFlowEntry flowEntryObj) {
-	String flowEntryIdStr = flowEntryObj.getFlowEntryId();
-	if (flowEntryIdStr == null)
-	    return false;
-	FlowEntryId flowEntryId = new FlowEntryId(flowEntryIdStr);
-	String userState = flowEntryObj.getUserState();
-	if (userState == null)
-	    return false;
-
-	//
-	// Create the Open Flow Flow Modification Entry to push
-	//
-	OFFlowMod fm = (OFFlowMod)messageFactory.getMessage(OFType.FLOW_MOD);
-	long cookie = flowEntryId.value();
-
-	short flowModCommand = OFFlowMod.OFPFC_ADD;
-	if (userState.equals("FE_USER_ADD")) {
-	    flowModCommand = OFFlowMod.OFPFC_ADD;
-	} else if (userState.equals("FE_USER_MODIFY")) {
-	    flowModCommand = OFFlowMod.OFPFC_MODIFY_STRICT;
-	} else if (userState.equals("FE_USER_DELETE")) {
-	    flowModCommand = OFFlowMod.OFPFC_DELETE_STRICT;
-	} else {
-	    // Unknown user state. Ignore the entry
-	    log.debug("Flow Entry ignored (FlowEntryId = {}): unknown user state {}",
-		      flowEntryId.toString(), userState);
-	    return false;
-	}
-
-	//
-	// Fetch the match conditions.
-	//
-	// NOTE: The Flow matching conditions common for all Flow Entries are
-	// used ONLY if a Flow Entry does NOT have the corresponding matching
-	// condition set.
-	//
-	OFMatch match = new OFMatch();
-	match.setWildcards(OFMatch.OFPFW_ALL);
-
-	// Match the Incoming Port
-	Short matchInPort = flowEntryObj.getMatchInPort();
-	if (matchInPort != null) {
-	    match.setInputPort(matchInPort);
-	    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_IN_PORT);
-	}
-
-	// Match the Source MAC address
-	String matchSrcMac = flowEntryObj.getMatchSrcMac();
-	if (matchSrcMac == null)
-	    matchSrcMac = flowObj.getMatchSrcMac();
-	if (matchSrcMac != null) {
-	    match.setDataLayerSource(matchSrcMac);
-	    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_DL_SRC);
-	}
-
-	// Match the Destination MAC address
-	String matchDstMac = flowEntryObj.getMatchDstMac();
-	if (matchDstMac == null)
-	    matchDstMac = flowObj.getMatchDstMac();
-	if (matchDstMac != null) {
-	    match.setDataLayerDestination(matchDstMac);
-	    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_DL_DST);
-	}
-
-	// Match the Ethernet Frame Type
-	Short matchEthernetFrameType = flowEntryObj.getMatchEthernetFrameType();
-	if (matchEthernetFrameType == null)
-	    matchEthernetFrameType = flowObj.getMatchEthernetFrameType();
-	if (matchEthernetFrameType != null) {
-	    match.setDataLayerType(matchEthernetFrameType);
-	    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_DL_TYPE);
-	}
-
-	// Match the VLAN ID
-	Short matchVlanId = flowEntryObj.getMatchVlanId();
-	if (matchVlanId == null)
-	    matchVlanId = flowObj.getMatchVlanId();
-	if (matchVlanId != null) {
-	    match.setDataLayerVirtualLan(matchVlanId);
-	    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_DL_VLAN);
-	}
-
-	// Match the VLAN priority
-	Byte matchVlanPriority = flowEntryObj.getMatchVlanPriority();
-	if (matchVlanPriority == null)
-	    matchVlanPriority = flowObj.getMatchVlanPriority();
-	if (matchVlanPriority != null) {
-	    match.setDataLayerVirtualLanPriorityCodePoint(matchVlanPriority);
-	    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_DL_VLAN_PCP);
-	}
-
-	// Match the Source IPv4 Network prefix
-	String matchSrcIPv4Net = flowEntryObj.getMatchSrcIPv4Net();
-	if (matchSrcIPv4Net == null)
-	    matchSrcIPv4Net = flowObj.getMatchSrcIPv4Net();
-	if (matchSrcIPv4Net != null) {
-	    match.setFromCIDR(matchSrcIPv4Net, OFMatch.STR_NW_SRC);
-	}
-
-	// Natch the Destination IPv4 Network prefix
-	String matchDstIPv4Net = flowEntryObj.getMatchDstIPv4Net();
-	if (matchDstIPv4Net == null)
-	    matchDstIPv4Net = flowObj.getMatchDstIPv4Net();
-	if (matchDstIPv4Net != null) {
-	    match.setFromCIDR(matchDstIPv4Net, OFMatch.STR_NW_DST);
-	}
-
-	// Match the IP protocol
-	Byte matchIpProto = flowEntryObj.getMatchIpProto();
-	if (matchIpProto == null)
-	    matchIpProto = flowObj.getMatchIpProto();
-	if (matchIpProto != null) {
-	    match.setNetworkProtocol(matchIpProto);
-	    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_NW_PROTO);
-	}
-
-	// Match the IP ToS (DSCP field, 6 bits)
-	Byte matchIpToS = flowEntryObj.getMatchIpToS();
-	if (matchIpToS == null)
-	    matchIpToS = flowObj.getMatchIpToS();
-	if (matchIpToS != null) {
-	    match.setNetworkTypeOfService(matchIpToS);
-	    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_NW_TOS);
-	}
-
-	// Match the Source TCP/UDP port
-	Short matchSrcTcpUdpPort = flowEntryObj.getMatchSrcTcpUdpPort();
-	if (matchSrcTcpUdpPort == null)
-	    matchSrcTcpUdpPort = flowObj.getMatchSrcTcpUdpPort();
-	if (matchSrcTcpUdpPort != null) {
-	    match.setTransportSource(matchSrcTcpUdpPort);
-	    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_TP_SRC);
-	}
-
-	// Match the Destination TCP/UDP port
-	Short matchDstTcpUdpPort = flowEntryObj.getMatchDstTcpUdpPort();
-	if (matchDstTcpUdpPort == null)
-	    matchDstTcpUdpPort = flowObj.getMatchDstTcpUdpPort();
-	if (matchDstTcpUdpPort != null) {
-	    match.setTransportDestination(matchDstTcpUdpPort);
-	    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_TP_DST);
-	}
-
-	//
-	// Fetch the actions
-	//
-	Short actionOutputPort = null;
-	List<OFAction> openFlowActions = new ArrayList<OFAction>();
-	int actionsLen = 0;
-	FlowEntryActions flowEntryActions = null;
-	String actionsStr = flowEntryObj.getActions();
-	if (actionsStr != null)
-	    flowEntryActions = new FlowEntryActions(actionsStr);
-	else
-	    flowEntryActions = new FlowEntryActions();
-	for (FlowEntryAction action : flowEntryActions.actions()) {
-	    ActionOutput actionOutput = action.actionOutput();
-	    ActionSetVlanId actionSetVlanId = action.actionSetVlanId();
-	    ActionSetVlanPriority actionSetVlanPriority = action.actionSetVlanPriority();
-	    ActionStripVlan actionStripVlan = action.actionStripVlan();
-	    ActionSetEthernetAddr actionSetEthernetSrcAddr = action.actionSetEthernetSrcAddr();
-	    ActionSetEthernetAddr actionSetEthernetDstAddr = action.actionSetEthernetDstAddr();
-	    ActionSetIPv4Addr actionSetIPv4SrcAddr = action.actionSetIPv4SrcAddr();
-	    ActionSetIPv4Addr actionSetIPv4DstAddr = action.actionSetIPv4DstAddr();
-	    ActionSetIpToS actionSetIpToS = action.actionSetIpToS();
-	    ActionSetTcpUdpPort actionSetTcpUdpSrcPort = action.actionSetTcpUdpSrcPort();
-	    ActionSetTcpUdpPort actionSetTcpUdpDstPort = action.actionSetTcpUdpDstPort();
-	    ActionEnqueue actionEnqueue = action.actionEnqueue();
-
-	    if (actionOutput != null) {
-		actionOutputPort = actionOutput.port().value();
-		// XXX: The max length is hard-coded for now
-		OFActionOutput ofa =
-		    new OFActionOutput(actionOutput.port().value(),
-				       (short)0xffff);
-		openFlowActions.add(ofa);
-		actionsLen += ofa.getLength();
-	    }
-
-	    if (actionSetVlanId != null) {
-		OFActionVirtualLanIdentifier ofa =
-		    new OFActionVirtualLanIdentifier(actionSetVlanId.vlanId());
-		openFlowActions.add(ofa);
-		actionsLen += ofa.getLength();
-	    }
-
-	    if (actionSetVlanPriority != null) {
-		OFActionVirtualLanPriorityCodePoint ofa =
-		    new OFActionVirtualLanPriorityCodePoint(actionSetVlanPriority.vlanPriority());
-		openFlowActions.add(ofa);
-		actionsLen += ofa.getLength();
-	    }
-
-	    if (actionStripVlan != null) {
-		if (actionStripVlan.stripVlan() == true) {
-		    OFActionStripVirtualLan ofa = new OFActionStripVirtualLan();
-		    openFlowActions.add(ofa);
-		    actionsLen += ofa.getLength();
-		}
-	    }
-
-	    if (actionSetEthernetSrcAddr != null) {
-		OFActionDataLayerSource ofa = 
-		    new OFActionDataLayerSource(actionSetEthernetSrcAddr.addr().toBytes());
-		openFlowActions.add(ofa);
-		actionsLen += ofa.getLength();
-	    }
-
-	    if (actionSetEthernetDstAddr != null) {
-		OFActionDataLayerDestination ofa =
-		    new OFActionDataLayerDestination(actionSetEthernetDstAddr.addr().toBytes());
-		openFlowActions.add(ofa);
-		actionsLen += ofa.getLength();
-	    }
-
-	    if (actionSetIPv4SrcAddr != null) {
-		OFActionNetworkLayerSource ofa =
-		    new OFActionNetworkLayerSource(actionSetIPv4SrcAddr.addr().value());
-		openFlowActions.add(ofa);
-		actionsLen += ofa.getLength();
-	    }
-
-	    if (actionSetIPv4DstAddr != null) {
-		OFActionNetworkLayerDestination ofa =
-		    new OFActionNetworkLayerDestination(actionSetIPv4DstAddr.addr().value());
-		openFlowActions.add(ofa);
-		actionsLen += ofa.getLength();
-	    }
-
-	    if (actionSetIpToS != null) {
-		OFActionNetworkTypeOfService ofa =
-		    new OFActionNetworkTypeOfService(actionSetIpToS.ipToS());
-		openFlowActions.add(ofa);
-		actionsLen += ofa.getLength();
-	    }
-
-	    if (actionSetTcpUdpSrcPort != null) {
-		OFActionTransportLayerSource ofa =
-		    new OFActionTransportLayerSource(actionSetTcpUdpSrcPort.port());
-		openFlowActions.add(ofa);
-		actionsLen += ofa.getLength();
-	    }
-
-	    if (actionSetTcpUdpDstPort != null) {
-		OFActionTransportLayerDestination ofa =
-		    new OFActionTransportLayerDestination(actionSetTcpUdpDstPort.port());
-		openFlowActions.add(ofa);
-		actionsLen += ofa.getLength();
-	    }
-
-	    if (actionEnqueue != null) {
-		OFActionEnqueue ofa =
-		    new OFActionEnqueue(actionEnqueue.port().value(),
-					actionEnqueue.queueId());
-		openFlowActions.add(ofa);
-		actionsLen += ofa.getLength();
-	    }
-	}
-
-	fm.setIdleTimeout(FLOWMOD_DEFAULT_IDLE_TIMEOUT)
-	    .setHardTimeout(FLOWMOD_DEFAULT_HARD_TIMEOUT)
-	    .setPriority(PRIORITY_DEFAULT)
-	    .setBufferId(OFPacketOut.BUFFER_ID_NONE)
-	    .setCookie(cookie)
-	    .setCommand(flowModCommand)
-	    .setMatch(match)
-	    .setActions(openFlowActions)
-	    .setLengthU(OFFlowMod.MINIMUM_LENGTH + actionsLen);
-	fm.setOutPort(OFPort.OFPP_NONE.getValue());
-	if ((flowModCommand == OFFlowMod.OFPFC_DELETE) ||
-	    (flowModCommand == OFFlowMod.OFPFC_DELETE_STRICT)) {
-	    if (actionOutputPort != null)
-		fm.setOutPort(actionOutputPort);
-	}
-
-	//
-	// TODO: Set the following flag
-	// fm.setFlags(OFFlowMod.OFPFF_SEND_FLOW_REM);
-	// See method ForwardingBase::pushRoute()
-	//
-
-	//
-	// Write the message to the switch
-	//
-	log.debug("MEASUREMENT: Installing flow entry " + userState +
-		  " into switch DPID: " +
-		  mySwitch.getStringId() +
-		  " flowEntryId: " + flowEntryId.toString() +
-		  " srcMac: " + matchSrcMac + " dstMac: " + matchDstMac +
-		  " inPort: " + matchInPort + " outPort: " + actionOutputPort
-		  );
-	try {
-	    messageDamper.write(mySwitch, fm, null);
-	    mySwitch.flush();
-	    //
-	    // TODO: We should use the OpenFlow Barrier mechanism
-	    // to check for errors, and update the SwitchState
-	    // for a flow entry after the Barrier message is
-	    // is received.
-	    //
-	    flowEntryObj.setSwitchState("FE_SWITCH_UPDATED");
-	} catch (IOException e) {
-	    log.error("Failure writing flow mod from network map", e);
-	    return false;
-	}
-
-	return true;
-    }
-
-    /**
-     * Install a Flow Entry on a switch.
-     *
-     * @param messageFactory the OpenFlow message factory to use.
-     * @maram messageDamper the OpenFlow message damper to use.
-     * @param mySwitch the switch to install the Flow Entry into.
-     * @param flowPath the flow path for the flow entry to install.
-     * @param flowEntry the flow entry to install.
-     * @return true on success, otherwise false.
-     */
-    static boolean installFlowEntry(BasicFactory messageFactory,
-				    OFMessageDamper messageDamper,
-				    IOFSwitch mySwitch, FlowPath flowPath,
-				    FlowEntry flowEntry) {
-	//
-	// Create the OpenFlow Flow Modification Entry to push
-	//
-	OFFlowMod fm = (OFFlowMod)messageFactory.getMessage(OFType.FLOW_MOD);
-	long cookie = flowEntry.flowEntryId().value();
-
-	short flowModCommand = OFFlowMod.OFPFC_ADD;
-	if (flowEntry.flowEntryUserState() == FlowEntryUserState.FE_USER_ADD) {
-	    flowModCommand = OFFlowMod.OFPFC_ADD;
-	} else if (flowEntry.flowEntryUserState() == FlowEntryUserState.FE_USER_MODIFY) {
-	    flowModCommand = OFFlowMod.OFPFC_MODIFY_STRICT;
-	} else if (flowEntry.flowEntryUserState() == FlowEntryUserState.FE_USER_DELETE) {
-	    flowModCommand = OFFlowMod.OFPFC_DELETE_STRICT;
-	} else {
-	    // Unknown user state. Ignore the entry
-	    log.debug("Flow Entry ignored (FlowEntryId = {}): unknown user state {}",
-		      flowEntry.flowEntryId().toString(),
-		      flowEntry.flowEntryUserState());
-	    return false;
-	}
-
-	//
-	// Fetch the match conditions.
-	//
-	// NOTE: The Flow matching conditions common for all Flow Entries are
-	// used ONLY if a Flow Entry does NOT have the corresponding matching
-	// condition set.
-	//
-	OFMatch match = new OFMatch();
-	match.setWildcards(OFMatch.OFPFW_ALL);
-	FlowEntryMatch flowPathMatch = flowPath.flowEntryMatch();
-	FlowEntryMatch flowEntryMatch = flowEntry.flowEntryMatch();
-
-	// Match the Incoming Port
-	Port matchInPort = flowEntryMatch.inPort();
-	if (matchInPort != null) {
-	    match.setInputPort(matchInPort.value());
-	    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_IN_PORT);
-	}
-
-	// Match the Source MAC address
-	MACAddress matchSrcMac = flowEntryMatch.srcMac();
-	if ((matchSrcMac == null) && (flowPathMatch != null)) {
-	    matchSrcMac = flowPathMatch.srcMac();
-	}
-	if (matchSrcMac != null) {
-	    match.setDataLayerSource(matchSrcMac.toString());
-	    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_DL_SRC);
-	}
-
-	// Match the Destination MAC address
-	MACAddress matchDstMac = flowEntryMatch.dstMac();
-	if ((matchDstMac == null) && (flowPathMatch != null)) {
-	    matchDstMac = flowPathMatch.dstMac();
-	}
-	if (matchDstMac != null) {
-	    match.setDataLayerDestination(matchDstMac.toString());
-	    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_DL_DST);
-	}
-
-	// Match the Ethernet Frame Type
-	Short matchEthernetFrameType = flowEntryMatch.ethernetFrameType();
-	if ((matchEthernetFrameType == null) && (flowPathMatch != null)) {
-	    matchEthernetFrameType = flowPathMatch.ethernetFrameType();
-	}
-	if (matchEthernetFrameType != null) {
-	    match.setDataLayerType(matchEthernetFrameType);
-	    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_DL_TYPE);
-	}
-
-	// Match the VLAN ID
-	Short matchVlanId = flowEntryMatch.vlanId();
-	if ((matchVlanId == null) && (flowPathMatch != null)) {
-	    matchVlanId = flowPathMatch.vlanId();
-	}
-	if (matchVlanId != null) {
-	    match.setDataLayerVirtualLan(matchVlanId);
-	    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_DL_VLAN);
-	}
-
-	// Match the VLAN priority
-	Byte matchVlanPriority = flowEntryMatch.vlanPriority();
-	if ((matchVlanPriority == null) && (flowPathMatch != null)) {
-	    matchVlanPriority = flowPathMatch.vlanPriority();
-	}
-	if (matchVlanPriority != null) {
-	    match.setDataLayerVirtualLanPriorityCodePoint(matchVlanPriority);
-	    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_DL_VLAN_PCP);
-	}
-
-	// Match the Source IPv4 Network prefix
-	IPv4Net matchSrcIPv4Net = flowEntryMatch.srcIPv4Net();
-	if ((matchSrcIPv4Net == null) && (flowPathMatch != null)) {
-	    matchSrcIPv4Net = flowPathMatch.srcIPv4Net();
-	}
-	if (matchSrcIPv4Net != null) {
-	    match.setFromCIDR(matchSrcIPv4Net.toString(), OFMatch.STR_NW_SRC);
-	}
-
-	// Natch the Destination IPv4 Network prefix
-	IPv4Net matchDstIPv4Net = flowEntryMatch.dstIPv4Net();
-	if ((matchDstIPv4Net == null) && (flowPathMatch != null)) {
-	    matchDstIPv4Net = flowPathMatch.dstIPv4Net();
-	}
-	if (matchDstIPv4Net != null) {
-	    match.setFromCIDR(matchDstIPv4Net.toString(), OFMatch.STR_NW_DST);
-	}
-
-	// Match the IP protocol
-	Byte matchIpProto = flowEntryMatch.ipProto();
-	if ((matchIpProto == null) && (flowPathMatch != null)) {
-	    matchIpProto = flowPathMatch.ipProto();
-	}
-	if (matchIpProto != null) {
-	    match.setNetworkProtocol(matchIpProto);
-	    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_NW_PROTO);
-	}
-
-	// Match the IP ToS (DSCP field, 6 bits)
-	Byte matchIpToS = flowEntryMatch.ipToS();
-	if ((matchIpToS == null) && (flowPathMatch != null)) {
-	    matchIpToS = flowPathMatch.ipToS();
-	}
-	if (matchIpToS != null) {
-	    match.setNetworkTypeOfService(matchIpToS);
-	    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_NW_TOS);
-	}
-
-	// Match the Source TCP/UDP port
-	Short matchSrcTcpUdpPort = flowEntryMatch.srcTcpUdpPort();
-	if ((matchSrcTcpUdpPort == null) && (flowPathMatch != null)) {
-	    matchSrcTcpUdpPort = flowPathMatch.srcTcpUdpPort();
-	}
-	if (matchSrcTcpUdpPort != null) {
-	    match.setTransportSource(matchSrcTcpUdpPort);
-	    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_TP_SRC);
-	}
-
-	// Match the Destination TCP/UDP port
-	Short matchDstTcpUdpPort = flowEntryMatch.dstTcpUdpPort();
-	if ((matchDstTcpUdpPort == null) && (flowPathMatch != null)) {
-	    matchDstTcpUdpPort = flowPathMatch.dstTcpUdpPort();
-	}
-	if (matchDstTcpUdpPort != null) {
-	    match.setTransportDestination(matchDstTcpUdpPort);
-	    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_TP_DST);
-	}
-
-	//
-	// Fetch the actions
-	//
-	Short actionOutputPort = null;
-	List<OFAction> openFlowActions = new ArrayList<OFAction>();
-	int actionsLen = 0;
-	FlowEntryActions flowEntryActions = flowEntry.flowEntryActions();
-	//
-	for (FlowEntryAction action : flowEntryActions.actions()) {
-	    ActionOutput actionOutput = action.actionOutput();
-	    ActionSetVlanId actionSetVlanId = action.actionSetVlanId();
-	    ActionSetVlanPriority actionSetVlanPriority = action.actionSetVlanPriority();
-	    ActionStripVlan actionStripVlan = action.actionStripVlan();
-	    ActionSetEthernetAddr actionSetEthernetSrcAddr = action.actionSetEthernetSrcAddr();
-	    ActionSetEthernetAddr actionSetEthernetDstAddr = action.actionSetEthernetDstAddr();
-	    ActionSetIPv4Addr actionSetIPv4SrcAddr = action.actionSetIPv4SrcAddr();
-	    ActionSetIPv4Addr actionSetIPv4DstAddr = action.actionSetIPv4DstAddr();
-	    ActionSetIpToS actionSetIpToS = action.actionSetIpToS();
-	    ActionSetTcpUdpPort actionSetTcpUdpSrcPort = action.actionSetTcpUdpSrcPort();
-	    ActionSetTcpUdpPort actionSetTcpUdpDstPort = action.actionSetTcpUdpDstPort();
-	    ActionEnqueue actionEnqueue = action.actionEnqueue();
-
-	    if (actionOutput != null) {
-		actionOutputPort = actionOutput.port().value();
-		// XXX: The max length is hard-coded for now
-		OFActionOutput ofa =
-		    new OFActionOutput(actionOutput.port().value(),
-				       (short)0xffff);
-		openFlowActions.add(ofa);
-		actionsLen += ofa.getLength();
-	    }
-
-	    if (actionSetVlanId != null) {
-		OFActionVirtualLanIdentifier ofa =
-		    new OFActionVirtualLanIdentifier(actionSetVlanId.vlanId());
-		openFlowActions.add(ofa);
-		actionsLen += ofa.getLength();
-	    }
-
-	    if (actionSetVlanPriority != null) {
-		OFActionVirtualLanPriorityCodePoint ofa =
-		    new OFActionVirtualLanPriorityCodePoint(actionSetVlanPriority.vlanPriority());
-		openFlowActions.add(ofa);
-		actionsLen += ofa.getLength();
-	    }
-
-	    if (actionStripVlan != null) {
-		if (actionStripVlan.stripVlan() == true) {
-		    OFActionStripVirtualLan ofa = new OFActionStripVirtualLan();
-		    openFlowActions.add(ofa);
-		    actionsLen += ofa.getLength();
-		}
-	    }
-
-	    if (actionSetEthernetSrcAddr != null) {
-		OFActionDataLayerSource ofa = 
-		    new OFActionDataLayerSource(actionSetEthernetSrcAddr.addr().toBytes());
-		openFlowActions.add(ofa);
-		actionsLen += ofa.getLength();
-	    }
-
-	    if (actionSetEthernetDstAddr != null) {
-		OFActionDataLayerDestination ofa =
-		    new OFActionDataLayerDestination(actionSetEthernetDstAddr.addr().toBytes());
-		openFlowActions.add(ofa);
-		actionsLen += ofa.getLength();
-	    }
-
-	    if (actionSetIPv4SrcAddr != null) {
-		OFActionNetworkLayerSource ofa =
-		    new OFActionNetworkLayerSource(actionSetIPv4SrcAddr.addr().value());
-		openFlowActions.add(ofa);
-		actionsLen += ofa.getLength();
-	    }
-
-	    if (actionSetIPv4DstAddr != null) {
-		OFActionNetworkLayerDestination ofa =
-		    new OFActionNetworkLayerDestination(actionSetIPv4DstAddr.addr().value());
-		openFlowActions.add(ofa);
-		actionsLen += ofa.getLength();
-	    }
-
-	    if (actionSetIpToS != null) {
-		OFActionNetworkTypeOfService ofa =
-		    new OFActionNetworkTypeOfService(actionSetIpToS.ipToS());
-		openFlowActions.add(ofa);
-		actionsLen += ofa.getLength();
-	    }
-
-	    if (actionSetTcpUdpSrcPort != null) {
-		OFActionTransportLayerSource ofa =
-		    new OFActionTransportLayerSource(actionSetTcpUdpSrcPort.port());
-		openFlowActions.add(ofa);
-		actionsLen += ofa.getLength();
-	    }
-
-	    if (actionSetTcpUdpDstPort != null) {
-		OFActionTransportLayerDestination ofa =
-		    new OFActionTransportLayerDestination(actionSetTcpUdpDstPort.port());
-		openFlowActions.add(ofa);
-		actionsLen += ofa.getLength();
-	    }
-
-	    if (actionEnqueue != null) {
-		OFActionEnqueue ofa =
-		    new OFActionEnqueue(actionEnqueue.port().value(),
-					actionEnqueue.queueId());
-		openFlowActions.add(ofa);
-		actionsLen += ofa.getLength();
-	    }
-	}
-
-	fm.setIdleTimeout(FLOWMOD_DEFAULT_IDLE_TIMEOUT)
-	    .setHardTimeout(FLOWMOD_DEFAULT_HARD_TIMEOUT)
-	    .setPriority(PRIORITY_DEFAULT)
-	    .setBufferId(OFPacketOut.BUFFER_ID_NONE)
-	    .setCookie(cookie)
-	    .setCommand(flowModCommand)
-	    .setMatch(match)
-	    .setActions(openFlowActions)
-	    .setLengthU(OFFlowMod.MINIMUM_LENGTH + actionsLen);
-	fm.setOutPort(OFPort.OFPP_NONE.getValue());
-	if ((flowModCommand == OFFlowMod.OFPFC_DELETE) ||
-	    (flowModCommand == OFFlowMod.OFPFC_DELETE_STRICT)) {
-	    if (actionOutputPort != null)
-		fm.setOutPort(actionOutputPort);
-	}
-
-	//
-	// TODO: Set the following flag
-	// fm.setFlags(OFFlowMod.OFPFF_SEND_FLOW_REM);
-	// See method ForwardingBase::pushRoute()
-	//
-
-	//
-	// Write the message to the switch
-	//
-	log.debug("MEASUREMENT: Installing flow entry " +
-		  flowEntry.flowEntryUserState() +
-		  " into switch DPID: " +
-		  mySwitch.getStringId() +
-		  " flowEntryId: " + flowEntry.flowEntryId().toString() +
-		  " srcMac: " + matchSrcMac + " dstMac: " + matchDstMac +
-		  " inPort: " + matchInPort + " outPort: " + actionOutputPort
-		  );
-	try {
-	    messageDamper.write(mySwitch, fm, null);
-	    mySwitch.flush();
-	    //
-	    // TODO: We should use the OpenFlow Barrier mechanism
-	    // to check for errors, and update the SwitchState
-	    // for a flow entry after the Barrier message is
-	    // is received.
-	    //
-	    // TODO: The FlowEntry Object in Titan should be set
-	    // to FE_SWITCH_UPDATED.
-	    //
-	} catch (IOException e) {
-	    log.error("Failure writing flow mod from network map", e);
-	    return false;
-	}
-	return true;
-    }
-}
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/IFlowService.java b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/IFlowService.java
index f39acb5..8d2b797 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/IFlowService.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/IFlowService.java
@@ -2,11 +2,12 @@
 
 import java.util.ArrayList;
 
+import net.floodlightcontroller.core.IOFSwitch;
 import net.floodlightcontroller.core.module.IFloodlightService;
-import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IFlowPath;
 import net.onrc.onos.ofcontroller.topology.Topology;
 import net.onrc.onos.ofcontroller.util.CallerId;
 import net.onrc.onos.ofcontroller.util.DataPathEndpoints;
+import net.onrc.onos.ofcontroller.util.FlowEntryId;
 import net.onrc.onos.ofcontroller.util.FlowId;
 import net.onrc.onos.ofcontroller.util.FlowPath;
 
@@ -42,21 +43,6 @@
     boolean deleteFlow(FlowId flowId);
 
     /**
-     * Clear the state for all previously added flows.
-     *
-     * @return true on success, otherwise false.
-     */
-    boolean clearAllFlows();
-
-    /**
-     * Clear the state for a previously added flow.
-     *
-     * @param flowId the Flow ID of the flow to clear.
-     * @return true on success, otherwise false.
-     */
-    boolean clearFlow(FlowId flowId);
-
-    /**
      * Get a previously added flow.
      *
      * @param flowId the Flow ID of the flow to get.
@@ -97,7 +83,7 @@
      * @param maxFlows number of flows to return
      * @return the Flow Paths if found, otherwise null.
      */
-    ArrayList<IFlowPath> getAllFlowsSummary(FlowId flowId, int maxFlows);
+    ArrayList<FlowPath> getAllFlowsSummary(FlowId flowId, int maxFlows);
     
     /**
      * Add and maintain a shortest-path flow.
@@ -128,4 +114,12 @@
      * @return unique flow ID
      */
     public long getNextFlowEntryId();
+
+    /**
+     * Inform the Flow Manager that a Flow Entry on switch expired.
+     *
+     * @param sw the switch the Flow Entry expired on.
+     * @param flowEntryId the Flow Entry ID of the expired Flow Entry.
+     */
+    public void flowEntryOnSwitchExpired(IOFSwitch sw, FlowEntryId flowEntryId);
 }
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/ClearFlowResource.java b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/ClearFlowResource.java
deleted file mode 100644
index b8942b9..0000000
--- a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/ClearFlowResource.java
+++ /dev/null
@@ -1,54 +0,0 @@
-package net.onrc.onos.ofcontroller.flowmanager.web;
-
-import net.onrc.onos.ofcontroller.flowmanager.IFlowService;
-import net.onrc.onos.ofcontroller.util.FlowId;
-
-import org.restlet.resource.Get;
-import org.restlet.resource.ServerResource;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-/**
- * Flow Manager REST API implementation: Clear internal Flow state.
- *
- * The "{flow-id}" request attribute value can be either a specific Flow ID,
- * or the keyword "all" to clear all Flows:
- *
- *   GET /wm/flow/clear/{flow-id}/json
- */
-public class ClearFlowResource extends ServerResource {
-    protected final static Logger log = LoggerFactory.getLogger(ClearFlowResource.class);
-
-    /**
-     * Implement the API.
-     *
-     * @return true on success, otehrwise false.
-     */
-    @Get("json")
-    public Boolean retrieve() {
-	Boolean result = false;
-
-        IFlowService flowService =
-                (IFlowService)getContext().getAttributes().
-                get(IFlowService.class.getCanonicalName());
-
-        if (flowService == null) {
-	    log.debug("ONOS Flow Service not found");
-            return result;
-	}
-
-	// Extract the arguments
-	String flowIdStr = (String) getRequestAttributes().get("flow-id");
-
-	// Process the request
-	if (flowIdStr.equals("all")) {
-	    log.debug("Clear All Flows");
-	    result = flowService.clearAllFlows();
-	} else {
-	    FlowId flowId = new FlowId(flowIdStr);
-	    log.debug("Clear Flow Id: " + flowIdStr);
-	    result = flowService.clearFlow(flowId);
-	}
-	return result;
-    }
-}
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/FlowWebRoutable.java b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/FlowWebRoutable.java
index e027270..81d26dd 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/FlowWebRoutable.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/FlowWebRoutable.java
@@ -18,7 +18,6 @@
         Router router = new Router(context);
         router.attach("/add/json", AddFlowResource.class);
         router.attach("/add-shortest-path/json", AddShortestPathFlowResource.class);
-        router.attach("/clear/{flow-id}/json", ClearFlowResource.class);
         router.attach("/delete/{flow-id}/json", DeleteFlowResource.class);
         router.attach("/get/{flow-id}/json", GetFlowByIdResource.class);
         router.attach("/getall-by-installer-id/{installer-id}/{src-dpid}/{src-port}/{dst-dpid}/{dst-port}/json", GetAllFlowsByInstallerIdResource.class);
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/GetSummaryFlowsResource.java b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/GetSummaryFlowsResource.java
index 89e5b01..58f82a9 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/GetSummaryFlowsResource.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/GetSummaryFlowsResource.java
@@ -2,8 +2,8 @@
 
 import java.util.ArrayList;
 
-import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IFlowPath;
 import net.onrc.onos.ofcontroller.flowmanager.IFlowService;
+import net.onrc.onos.ofcontroller.util.FlowPath;
 import net.onrc.onos.ofcontroller.util.FlowId;
 
 import org.restlet.resource.Get;
@@ -31,8 +31,8 @@
      * @return the collection of Flow states if any found, otherwise null.
      */
     @Get("json")
-    public ArrayList<IFlowPath> retrieve() {
-    	ArrayList<IFlowPath> result = null;
+    public ArrayList<FlowPath> retrieve() {
+    	ArrayList<FlowPath> result = null;
     	
     	FlowId flowId;
     	int maxFlows = 0;
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowProgrammer.java b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowProgrammer.java
index a59a9f9..461d231 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowProgrammer.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowProgrammer.java
@@ -4,26 +4,62 @@
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;
+
+import org.openflow.protocol.OFFlowRemoved;
+import org.openflow.protocol.OFMessage;
+import org.openflow.protocol.OFType;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import net.floodlightcontroller.core.FloodlightContext;
 import net.floodlightcontroller.core.IFloodlightProviderService;
+import net.floodlightcontroller.core.IOFMessageListener;
+import net.floodlightcontroller.core.IOFSwitch;
+import net.floodlightcontroller.core.IOFSwitchListener;
 import net.floodlightcontroller.core.module.FloodlightModuleContext;
 import net.floodlightcontroller.core.module.FloodlightModuleException;
 import net.floodlightcontroller.core.module.IFloodlightModule;
 import net.floodlightcontroller.core.module.IFloodlightService;
+import net.floodlightcontroller.restserver.IRestApiService;
+import net.onrc.onos.ofcontroller.flowprogrammer.web.FlowProgrammerWebRoutable;
+import net.onrc.onos.ofcontroller.flowmanager.IFlowService;
+import net.onrc.onos.ofcontroller.util.FlowEntryId;
+import net.onrc.onos.registry.controller.IControllerRegistryService;
 
-public class FlowProgrammer implements IFloodlightModule {
-	private static final boolean enableFlowSync = false;
-	
+/**
+ * FlowProgrammer is a module responsible to maintain flows installed to switches.
+ * FlowProgrammer consists of FlowPusher and FlowSynchronizer.
+ * FlowPusher manages the rate of installation, and FlowSynchronizer synchronizes
+ * flows between GraphDB and switches.
+ * FlowProgrammer also watch the event of addition/deletion of switches to
+ * start/stop synchronization. When a switch is added to network, FlowProgrammer
+ * immediately kicks synchronization to keep switch's flow table latest state.
+ * Adversely, when a switch is removed from network, FlowProgrammer immediately
+ * stops synchronization.
+ * @author Brian
+ *
+ */
+public class FlowProgrammer implements IFloodlightModule, 
+				       IOFMessageListener,
+				       IOFSwitchListener {
+    @SuppressWarnings("unused")
+    // flag to enable FlowSynchronizer
+    private static final boolean enableFlowSync = false;
+    protected static Logger log = LoggerFactory.getLogger(FlowProgrammer.class);
     protected volatile IFloodlightProviderService floodlightProvider;
+    protected volatile IControllerRegistryService registryService;
+    protected volatile IRestApiService restApi;
+    protected volatile IFlowService flowManager;
 
     protected FlowPusher pusher;
     private static final int NUM_PUSHER_THREAD = 1;
 
     protected FlowSynchronizer synchronizer;
-        
+    
     public FlowProgrammer() {
 	pusher = new FlowPusher(NUM_PUSHER_THREAD);
 	if (enableFlowSync) {
-	synchronizer = new FlowSynchronizer();
+	    synchronizer = new FlowSynchronizer();
 	}
     }
     
@@ -31,18 +67,21 @@
     public void init(FloodlightModuleContext context)
 	    throws FloodlightModuleException {
 	floodlightProvider = context.getServiceImpl(IFloodlightProviderService.class);
-	pusher.init(null, floodlightProvider.getOFMessageFactory(), null);
+	registryService = context.getServiceImpl(IControllerRegistryService.class);
+	restApi = context.getServiceImpl(IRestApiService.class);
+	flowManager = context.getServiceImpl(IFlowService.class);
+	pusher.init(null, context, floodlightProvider.getOFMessageFactory(), null);
 	if (enableFlowSync) {
-	synchronizer.init(context);
+	    synchronizer.init(pusher);
 	}
     }
 
     @Override
     public void startUp(FloodlightModuleContext context) {
+    restApi.addRestletRoutable(new FlowProgrammerWebRoutable());
 	pusher.start();
-	if (enableFlowSync) {
-	synchronizer.startUp(context);
-	}
+	floodlightProvider.addOFMessageListener(OFType.FLOW_REMOVED, this);
+	floodlightProvider.addOFSwitchListener(this);
     }
 
     @Override
@@ -51,7 +90,7 @@
 		new ArrayList<Class<? extends IFloodlightService>>();
 	l.add(IFlowPusherService.class);
 	if (enableFlowSync) {
-	l.add(IFlowSyncService.class);
+	    l.add(IFlowSyncService.class);
 	}
 	return l;
     }
@@ -64,7 +103,7 @@
 	    IFloodlightService>();
 	m.put(IFlowPusherService.class, pusher);
 	if (enableFlowSync) {
-	m.put(IFlowSyncService.class, synchronizer);
+	    m.put(IFlowSyncService.class, synchronizer);
 	}
 	return m;
     }
@@ -74,8 +113,65 @@
 	Collection<Class<? extends IFloodlightService>> l =
 		new ArrayList<Class<? extends IFloodlightService>>();
 	l.add(IFloodlightProviderService.class);
+	l.add(IRestApiService.class);
 	return l;
     }
-    
 
+    @Override
+    public String getName() {
+	// TODO Auto-generated method stub
+	return "FlowProgrammer";
+    }
+
+    @Override
+    public boolean isCallbackOrderingPrereq(OFType type, String name) {
+	// TODO Auto-generated method stub
+	return false;
+    }
+
+    @Override
+    public boolean isCallbackOrderingPostreq(OFType type, String name) {
+	// TODO Auto-generated method stub
+	return false;
+    }
+
+    @Override
+    public Command receive(IOFSwitch sw, OFMessage msg, FloodlightContext cntx) {
+	switch (msg.getType()) {
+	case FLOW_REMOVED:
+	    OFFlowRemoved flowMsg = (OFFlowRemoved) msg;
+	    log.debug("Got flow removed from "+ sw.getId() +": "+ flowMsg.getCookie());
+	    FlowEntryId id = new FlowEntryId(flowMsg.getCookie());
+	    flowManager.flowEntryOnSwitchExpired(sw, id);
+	    break;
+	default:
+	    break;
+	}
+
+	return Command.CONTINUE;
+    }
+
+    @Override
+    public void addedSwitch(IOFSwitch sw) {
+	log.debug("Switch added: {}", sw.getId());
+
+	if (enableFlowSync && registryService.hasControl(sw.getId())) {
+	    synchronizer.synchronize(sw);
+	}
+    }
+
+    @Override
+    public void removedSwitch(IOFSwitch sw) {
+	log.debug("Switch removed: {}", sw.getId());
+	
+	if (enableFlowSync) {
+	    synchronizer.interrupt(sw);
+	}
+    }
+
+    @Override
+    public void switchPortChanged(Long switchId) {
+	// TODO Auto-generated method stub
+    }
+    
 }
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowPusher.java b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowPusher.java
index 532477a..438f478 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowPusher.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowPusher.java
@@ -5,9 +5,12 @@
 import java.util.ArrayList;
 import java.util.EnumSet;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Semaphore;
 
 import org.openflow.protocol.*;
 import org.openflow.protocol.action.*;
@@ -16,11 +19,14 @@
 import org.slf4j.LoggerFactory;
 
 import net.floodlightcontroller.core.FloodlightContext;
+import net.floodlightcontroller.core.IFloodlightProviderService;
+import net.floodlightcontroller.core.IOFMessageListener;
 import net.floodlightcontroller.core.IOFSwitch;
+import net.floodlightcontroller.core.internal.OFMessageFuture;
+import net.floodlightcontroller.core.module.FloodlightModuleContext;
+import net.floodlightcontroller.threadpool.IThreadPoolService;
 import net.floodlightcontroller.util.MACAddress;
 import net.floodlightcontroller.util.OFMessageDamper;
-import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IFlowEntry;
-import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IFlowPath;
 import net.onrc.onos.ofcontroller.util.FlowEntryAction;
 import net.onrc.onos.ofcontroller.util.FlowEntryAction.*;
 import net.onrc.onos.ofcontroller.util.FlowEntry;
@@ -28,17 +34,22 @@
 import net.onrc.onos.ofcontroller.util.FlowEntryId;
 import net.onrc.onos.ofcontroller.util.FlowEntryMatch;
 import net.onrc.onos.ofcontroller.util.FlowEntryUserState;
-import net.onrc.onos.ofcontroller.util.FlowPath;
 import net.onrc.onos.ofcontroller.util.IPv4Net;
 import net.onrc.onos.ofcontroller.util.Port;
 
 /**
- * FlowPusher intermediates FlowManager/FlowSynchronizer and switches to push OpenFlow
- * messages to switches in proper rate.
+ * FlowPusher is a implementation of FlowPusherService.
+ * FlowPusher assigns one message queue instance for each one switch.
+ * Number of message processing threads is configurable by constructor, and
+ * one thread can handle multiple message queues. Each queue will be assigned to 
+ * a thread according to hash function defined by getHash().
+ * Each processing thread reads messages from queues and sends it to switches
+ * in round-robin. Processing thread also calculates rate of sending to suppress
+ * excessive message sending.
  * @author Naoki Shiota
  *
  */
-public class FlowPusher implements IFlowPusherService {
+public class FlowPusher implements IFlowPusherService, IOFMessageListener {
     private final static Logger log = LoggerFactory.getLogger(FlowPusher.class);
 
     // NOTE: Below are moved from FlowManager.
@@ -48,10 +59,6 @@
     protected static final int OFMESSAGE_DAMPER_CAPACITY = 50000; // TODO: find sweet spot
     protected static final int OFMESSAGE_DAMPER_TIMEOUT = 250;	// ms
     
-    // Interval of sleep when queue is empty
-    protected static final long SLEEP_MILLI_SEC = 10;
-    protected static final int SLEEP_NANO_SEC = 0;
-    
     // Number of messages sent to switch at once
     protected static final int MAX_MESSAGE_SEND = 100;
 
@@ -64,15 +71,24 @@
 		SUSPENDED,
 	}
 	
+	/**
+	 * SwitchQueue represents message queue attached to a switch.
+	 * This consists of queue itself and variables used for limiting sending rate.
+	 * @author Naoki Shiota
+	 *
+	 */
 	@SuppressWarnings("serial")
 	private class SwitchQueue extends ArrayDeque<OFMessage> {
 		QueueState state;
 		
-		// Max rate of sending message (bytes/sec). 0 implies no limitation.
+		// Max rate of sending message (bytes/ms). 0 implies no limitation.
 		long max_rate = 0;	// 0 indicates no limitation
 		long last_sent_time = 0;
 		long last_sent_size = 0;
 		
+		// "To be deleted" flag
+		boolean toBeDeleted = false;
+		
 		/**
 		 * Check if sending rate is within the rate
 		 * @param current Current time
@@ -84,15 +100,20 @@
 				return true;
 			}
 			
-			long rate = last_sent_size / (current - last_sent_time);
-			
-			if (rate < max_rate) {
-				return true;
-			} else {
+			if (current == last_sent_time) {
 				return false;
 			}
+			
+			// Check if sufficient time (from aspect of rate) elapsed or not.
+			long rate = last_sent_size / (current - last_sent_time);
+			return (rate < max_rate);
 		}
 		
+		/**
+		 * Log time and size of last sent data.
+		 * @param current Time to be sent.
+		 * @param size Size of sent data (in bytes).
+		 */
 		void logSentData(long current, long size) {
 			last_sent_time = current;
 			last_sent_size = size;
@@ -100,11 +121,17 @@
 		
 	}
 	
-	private OFMessageDamper messageDamper;
+	private OFMessageDamper messageDamper = null;
+	private IThreadPoolService threadPool = null;
 
 	private FloodlightContext context = null;
 	private BasicFactory factory = null;
-	private Map<Long, FlowPusherProcess> threadMap = null;
+	
+	// Map of threads versus dpid
+	private Map<Long, FlowPusherThread> threadMap = null;
+	// Map of Future objects versus dpid and transaction ID.
+	private Map<Long, Map<Integer, OFBarrierReplyFuture>>
+		barrierFutures = new HashMap<Long, Map<Integer, OFBarrierReplyFuture>>();
 	
 	private int number_thread = 1;
 	
@@ -113,29 +140,35 @@
 	 * @author Naoki Shiota
 	 *
 	 */
-	private class FlowPusherProcess implements Runnable {
+	private class FlowPusherThread extends Thread {
 		private Map<IOFSwitch,SwitchQueue> queues
-		= new HashMap<IOFSwitch,SwitchQueue>();
+			= new HashMap<IOFSwitch,SwitchQueue>();
 		
-		private boolean isStopped = false;
-		private boolean isMsgAdded = false;
+		// reusable latch used for waiting for arrival of message
+		private Semaphore mutex = new Semaphore(0);
 		
 		@Override
 		public void run() {
-			log.debug("Begin Flow Pusher Process");
-			
 			while (true) {
-				Set< Map.Entry<IOFSwitch,SwitchQueue> > entries;
-				synchronized (queues) {
-					entries = queues.entrySet();
+				try {
+					// wait for message pushed to queue
+					mutex.acquire();
+				} catch (InterruptedException e) {
+					// not an error
+					log.debug("FlowPusherThread is interrupted");
+					return;
 				}
 				
-				// Set taint flag to false at this moment.
-				isMsgAdded = false;
+				// for safety of concurrent access, copy all key objects
+				Set<IOFSwitch> keys = new HashSet<IOFSwitch>(queues.size());
+				synchronized (queues) {
+					for (IOFSwitch sw : queues.keySet()) {
+						keys.add(sw);
+					}
+				}
 				
-				for (Map.Entry<IOFSwitch,SwitchQueue> entry : entries) {
-					IOFSwitch sw = entry.getKey();
-					SwitchQueue queue = entry.getValue();
+				for (IOFSwitch sw : keys) {
+					SwitchQueue queue = queues.get(sw);
 
 					// Skip if queue is suspended
 					if (sw == null || queue == null ||
@@ -143,76 +176,102 @@
 						continue;
 					}
 					
-					// check sending rate and determine it to be sent or not
-					long current_time = System.nanoTime();
-					long size = 0;
-					
 					synchronized (queue) {
-						if (queue.isSendable(current_time)) {
-							int i = 0;
-							while (! queue.isEmpty()) {
-								// Number of messages excess the limit
-								if (++i >= MAX_MESSAGE_SEND) {
-									// Messages remains in queue
-									isMsgAdded = true;
-									break;
-								}
-								
-								OFMessage msg = queue.poll();
-								
-								// if need to send, call IOFSwitch#write()
-								try {
-									messageDamper.write(sw, msg, context);
-									log.debug("Pusher sends message : {}", msg);
-									size += msg.getLength();
-								} catch (IOException e) {
-									e.printStackTrace();
-									log.error("Exception in sending message ({}) : {}", msg, e);
+						processQueue(sw, queue, MAX_MESSAGE_SEND);
+						if (queue.isEmpty()) {
+							// remove queue if flagged to be.
+							if (queue.toBeDeleted) {
+								synchronized (queues) {
+									queues.remove(sw);
 								}
 							}
-							sw.flush();
-							queue.logSentData(current_time, size);
+						} else {
+							// if some messages remains in queue, latch down
+							if (mutex.availablePermits() == 0) {
+								mutex.release();
+							}
 						}
 					}
 				}
-				
-				// sleep while all queues are empty
-				while (! (isMsgAdded || isStopped)) {
+			}
+		}
+		
+		/**
+		 * Read messages from queue and send them to the switch.
+		 * If number of messages excess the limit, stop sending messages.
+		 * @param sw Switch to which messages will be sent.
+		 * @param queue Queue of messages.
+		 * @param max_msg Limitation of number of messages to be sent. If set to 0,
+		 *                all messages in queue will be sent.
+		 */
+		private void processQueue(IOFSwitch sw, SwitchQueue queue, long max_msg) {
+			// check sending rate and determine it to be sent or not
+			long current_time = System.currentTimeMillis();
+			long size = 0;
+			
+			if (queue.isSendable(current_time)) {
+				int i = 0;
+				while (! queue.isEmpty()) {
+					// Number of messages excess the limit
+					if (0 < max_msg && max_msg <= i) {
+						break;
+					}
+					++i;
+					
+					OFMessage msg = queue.poll();
 					try {
-						Thread.sleep(SLEEP_MILLI_SEC, SLEEP_NANO_SEC);
-					} catch (InterruptedException e) {
+						messageDamper.write(sw, msg, context);
+//						log.debug("Pusher sends message : {}", msg);
+						size += msg.getLength();
+					} catch (IOException e) {
 						e.printStackTrace();
-						log.error("Thread.sleep failed");
+						log.error("Exception in sending message ({}) : {}", msg, e);
 					}
 				}
-				
-				log.debug("Exit sleep loop.");
-				
-				if (isStopped) {
-					log.debug("Pusher Process finished.");
-					return;
-				}
-
+				sw.flush();
+				queue.logSentData(current_time, size);
 			}
 		}
 	}
 	
+	/**
+	 * Initialize object with one thread.
+	 */
 	public FlowPusher() {
-		
 	}
 	
+	/**
+	 * Initialize object with threads of given number.
+	 * @param number_thread Number of threads to handle messages.
+	 */
 	public FlowPusher(int number_thread) {
 		this.number_thread = number_thread;
 	}
 	
-	public void init(FloodlightContext context, BasicFactory factory, OFMessageDamper damper) {
+	/**
+	 * Set parameters needed for sending messages.
+	 * @param context FloodlightContext used for sending messages.
+	 *        If null, FlowPusher uses default context.
+	 * @param modContext FloodlightModuleContext used for acquiring
+	 *        ThreadPoolService and registering MessageListener.
+	 * @param factory Factory object to create OFMessage objects.
+	 * @param damper Message damper used for sending messages.
+	 *        If null, FlowPusher creates its own damper object.
+	 */
+	public void init(FloodlightContext context,
+			FloodlightModuleContext modContext,
+			BasicFactory factory,
+			OFMessageDamper damper) {
 		this.context = context;
 		this.factory = factory;
+		this.threadPool = modContext.getServiceImpl(IThreadPoolService.class);
+		IFloodlightProviderService flservice = modContext.getServiceImpl(IFloodlightProviderService.class);
+		flservice.addOFMessageListener(OFType.BARRIER_REPLY, this);
 		
 		if (damper != null) {
 			messageDamper = damper;
 		} else {
-			// use default value
+			// use default values
 			messageDamper = new OFMessageDamper(OFMESSAGE_DAMPER_CAPACITY,
 				    EnumSet.of(OFType.FLOW_MOD),
 				    OFMESSAGE_DAMPER_TIMEOUT);
@@ -228,20 +287,15 @@
 			return;
 		}
 		
-		threadMap = new HashMap<Long,FlowPusherProcess>();
+		threadMap = new HashMap<Long,FlowPusherThread>();
 		for (long i = 0; i < number_thread; ++i) {
-			FlowPusherProcess runnable = new FlowPusherProcess();
-			threadMap.put(i, runnable);
+			FlowPusherThread thread = new FlowPusherThread();
 			
-			Thread thread = new Thread(runnable);
+			threadMap.put(i, thread);
 			thread.start();
 		}
 	}
 	
-	/**
-	 * Suspend sending messages to switch.
-	 * @param sw
-	 */
 	@Override
 	public boolean suspend(IOFSwitch sw) {
 		SwitchQueue queue = getQueue(sw);
@@ -259,9 +313,6 @@
 		}
 	}
 
-	/**
-	 * Resume sending messages to switch.
-	 */
 	@Override
 	public boolean resume(IOFSwitch sw) {
 		SwitchQueue queue = getQueue(sw);
@@ -273,15 +324,19 @@
 		synchronized (queue) {
 			if (queue.state == QueueState.SUSPENDED) {
 				queue.state = QueueState.READY;
+				
+				// Latch down if queue is not empty
+				FlowPusherThread thread = getProcess(sw);
+				if (! queue.isEmpty() &&
+						thread.mutex.availablePermits() == 0) {
+					thread.mutex.release();
+				}
 				return true;
 			}
 			return false;
 		}
 	}
 	
-	/**
-	 * Check if given switch is suspended.
-	 */
 	@Override
 	public boolean isSuspended(IOFSwitch sw) {
 		SwitchQueue queue = getQueue(sw);
@@ -302,18 +357,12 @@
 			return;
 		}
 		
-		for (FlowPusherProcess runnable : threadMap.values()) {
-			if (! runnable.isStopped) {
-				runnable.isStopped = true;
-			}
+		for (FlowPusherThread t : threadMap.values()) {
+			t.interrupt();
 		}
 	}
 	
-	/**
-	 * Set sending rate to a switch.
-	 * @param sw Switch.
-	 * @param rate Rate in bytes/sec.
-	 */
+	@Override
 	public void setRate(IOFSwitch sw, long rate) {
 		SwitchQueue queue = getQueue(sw);
 		if (queue == null) {
@@ -321,360 +370,82 @@
 		}
 		
 		if (rate > 0) {
+			log.debug("rate for {} is set to {}", sw.getId(), rate);
 			queue.max_rate = rate;
 		}
 	}
+
+	@Override
+	public boolean createQueue(IOFSwitch sw) {
+		SwitchQueue queue = getQueue(sw);
+		if (queue != null) {
+			return false;
+		}
+		
+		FlowPusherThread proc = getProcess(sw);
+		queue = new SwitchQueue();
+		queue.state = QueueState.READY;
+		synchronized (proc.queues) {
+			proc.queues.put(sw, queue);
+		}
+		
+		return true;
+	}
+
+	@Override
+	public boolean deleteQueue(IOFSwitch sw) {
+		return deleteQueue(sw, false);
+	}
 	
-	/**
-	 * Add OFMessage to the queue related to given switch.
-	 * @param sw Switch to which message is sent.
-	 * @param msg Message to be sent.
-	 * @return true if succeed.
-	 */
+	@Override
+	public boolean deleteQueue(IOFSwitch sw, boolean forceStop) {
+		FlowPusherThread proc = getProcess(sw);
+		
+		if (forceStop) {
+			synchronized (proc.queues) {
+				SwitchQueue queue = proc.queues.remove(sw);
+				if (queue == null) {
+					return false;
+				}
+			}
+			return true;
+		} else {
+			SwitchQueue queue = getQueue(sw);
+			if (queue == null) {
+				return false;
+			}
+			synchronized (queue) {
+				queue.toBeDeleted = true;
+			}
+			return true;
+		}
+	}
+	
 	@Override
 	public boolean add(IOFSwitch sw, OFMessage msg) {
-		FlowPusherProcess proc = getProcess(sw);
+		FlowPusherThread proc = getProcess(sw);
 		SwitchQueue queue = proc.queues.get(sw);
 
+		// create queue at first addition of message
 		if (queue == null) {
-			queue = new SwitchQueue();
-			queue.state = QueueState.READY;
-			synchronized (proc) {
-				proc.queues.put(sw, queue);
-			}
+			createQueue(sw);
+			queue = getQueue(sw);
 		}
 		
 		synchronized (queue) {
 			queue.add(msg);
-			log.debug("Message is pushed : {}", msg);
+//			log.debug("Message is pushed : {}", msg);
 		}
 		
-		proc.isMsgAdded = true;
-		
-		return true;
-	}
-	
-	/**
-	 * Create OFMessage from given flow information and add it to the queue.
-	 * @param sw Switch to which message is sent.
-	 * @param flowObj FlowPath.
-	 * @param flowEntryObj FlowEntry.
-	 * @return true if succeed.
-	 */
-	@Override
-	public boolean add(IOFSwitch sw, IFlowPath flowObj, IFlowEntry flowEntryObj) {
-		log.debug("sending : {}, {}", sw, flowObj);
-		String flowEntryIdStr = flowEntryObj.getFlowEntryId();
-		if (flowEntryIdStr == null)
-		    return false;
-		FlowEntryId flowEntryId = new FlowEntryId(flowEntryIdStr);
-		String userState = flowEntryObj.getUserState();
-		if (userState == null)
-		    return false;
-
-		//
-		// Create the Open Flow Flow Modification Entry to push
-		//
-		OFFlowMod fm = (OFFlowMod)factory.getMessage(OFType.FLOW_MOD);
-		long cookie = flowEntryId.value();
-
-		short flowModCommand = OFFlowMod.OFPFC_ADD;
-		if (userState.equals("FE_USER_ADD")) {
-		    flowModCommand = OFFlowMod.OFPFC_ADD;
-		} else if (userState.equals("FE_USER_MODIFY")) {
-		    flowModCommand = OFFlowMod.OFPFC_MODIFY_STRICT;
-		} else if (userState.equals("FE_USER_DELETE")) {
-		    flowModCommand = OFFlowMod.OFPFC_DELETE_STRICT;
-		} else {
-		    // Unknown user state. Ignore the entry
-		    log.debug("Flow Entry ignored (FlowEntryId = {}): unknown user state {}",
-			      flowEntryId.toString(), userState);
-		    return false;
+		if (proc.mutex.availablePermits() == 0) {
+			proc.mutex.release();
 		}
 
-		//
-		// Fetch the match conditions.
-		//
-		// NOTE: The Flow matching conditions common for all Flow Entries are
-		// used ONLY if a Flow Entry does NOT have the corresponding matching
-		// condition set.
-		//
-		OFMatch match = new OFMatch();
-		match.setWildcards(OFMatch.OFPFW_ALL);
-
-		// Match the Incoming Port
-		Short matchInPort = flowEntryObj.getMatchInPort();
-		if (matchInPort != null) {
-		    match.setInputPort(matchInPort);
-		    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_IN_PORT);
-		}
-
-		// Match the Source MAC address
-		String matchSrcMac = flowEntryObj.getMatchSrcMac();
-		if (matchSrcMac == null)
-		    matchSrcMac = flowObj.getMatchSrcMac();
-		if (matchSrcMac != null) {
-		    match.setDataLayerSource(matchSrcMac);
-		    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_DL_SRC);
-		}
-
-		// Match the Destination MAC address
-		String matchDstMac = flowEntryObj.getMatchDstMac();
-		if (matchDstMac == null)
-		    matchDstMac = flowObj.getMatchDstMac();
-		if (matchDstMac != null) {
-		    match.setDataLayerDestination(matchDstMac);
-		    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_DL_DST);
-		}
-
-		// Match the Ethernet Frame Type
-		Short matchEthernetFrameType = flowEntryObj.getMatchEthernetFrameType();
-		if (matchEthernetFrameType == null)
-		    matchEthernetFrameType = flowObj.getMatchEthernetFrameType();
-		if (matchEthernetFrameType != null) {
-		    match.setDataLayerType(matchEthernetFrameType);
-		    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_DL_TYPE);
-		}
-
-		// Match the VLAN ID
-		Short matchVlanId = flowEntryObj.getMatchVlanId();
-		if (matchVlanId == null)
-		    matchVlanId = flowObj.getMatchVlanId();
-		if (matchVlanId != null) {
-		    match.setDataLayerVirtualLan(matchVlanId);
-		    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_DL_VLAN);
-		}
-
-		// Match the VLAN priority
-		Byte matchVlanPriority = flowEntryObj.getMatchVlanPriority();
-		if (matchVlanPriority == null)
-		    matchVlanPriority = flowObj.getMatchVlanPriority();
-		if (matchVlanPriority != null) {
-		    match.setDataLayerVirtualLanPriorityCodePoint(matchVlanPriority);
-		    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_DL_VLAN_PCP);
-		}
-
-		// Match the Source IPv4 Network prefix
-		String matchSrcIPv4Net = flowEntryObj.getMatchSrcIPv4Net();
-		if (matchSrcIPv4Net == null)
-		    matchSrcIPv4Net = flowObj.getMatchSrcIPv4Net();
-		if (matchSrcIPv4Net != null) {
-		    match.setFromCIDR(matchSrcIPv4Net, OFMatch.STR_NW_SRC);
-		}
-
-		// Match the Destination IPv4 Network prefix
-		String matchDstIPv4Net = flowEntryObj.getMatchDstIPv4Net();
-		if (matchDstIPv4Net == null)
-		    matchDstIPv4Net = flowObj.getMatchDstIPv4Net();
-		if (matchDstIPv4Net != null) {
-		    match.setFromCIDR(matchDstIPv4Net, OFMatch.STR_NW_DST);
-		}
-
-		// Match the IP protocol
-		Byte matchIpProto = flowEntryObj.getMatchIpProto();
-		if (matchIpProto == null)
-		    matchIpProto = flowObj.getMatchIpProto();
-		if (matchIpProto != null) {
-		    match.setNetworkProtocol(matchIpProto);
-		    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_NW_PROTO);
-		}
-
-		// Match the IP ToS (DSCP field, 6 bits)
-		Byte matchIpToS = flowEntryObj.getMatchIpToS();
-		if (matchIpToS == null)
-		    matchIpToS = flowObj.getMatchIpToS();
-		if (matchIpToS != null) {
-		    match.setNetworkTypeOfService(matchIpToS);
-		    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_NW_TOS);
-		}
-
-		// Match the Source TCP/UDP port
-		Short matchSrcTcpUdpPort = flowEntryObj.getMatchSrcTcpUdpPort();
-		if (matchSrcTcpUdpPort == null)
-		    matchSrcTcpUdpPort = flowObj.getMatchSrcTcpUdpPort();
-		if (matchSrcTcpUdpPort != null) {
-		    match.setTransportSource(matchSrcTcpUdpPort);
-		    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_TP_SRC);
-		}
-
-		// Match the Destination TCP/UDP port
-		Short matchDstTcpUdpPort = flowEntryObj.getMatchDstTcpUdpPort();
-		if (matchDstTcpUdpPort == null)
-		    matchDstTcpUdpPort = flowObj.getMatchDstTcpUdpPort();
-		if (matchDstTcpUdpPort != null) {
-		    match.setTransportDestination(matchDstTcpUdpPort);
-		    match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_TP_DST);
-		}
-
-		//
-		// Fetch the actions
-		//
-		Short actionOutputPort = null;
-		List<OFAction> openFlowActions = new ArrayList<OFAction>();
-		int actionsLen = 0;
-		FlowEntryActions flowEntryActions = null;
-		String actionsStr = flowEntryObj.getActions();
-		if (actionsStr != null)
-		    flowEntryActions = new FlowEntryActions(actionsStr);
-		else
-		    flowEntryActions = new FlowEntryActions();
-		for (FlowEntryAction action : flowEntryActions.actions()) {
-		    ActionOutput actionOutput = action.actionOutput();
-		    ActionSetVlanId actionSetVlanId = action.actionSetVlanId();
-		    ActionSetVlanPriority actionSetVlanPriority = action.actionSetVlanPriority();
-		    ActionStripVlan actionStripVlan = action.actionStripVlan();
-		    ActionSetEthernetAddr actionSetEthernetSrcAddr = action.actionSetEthernetSrcAddr();
-		    ActionSetEthernetAddr actionSetEthernetDstAddr = action.actionSetEthernetDstAddr();
-		    ActionSetIPv4Addr actionSetIPv4SrcAddr = action.actionSetIPv4SrcAddr();
-		    ActionSetIPv4Addr actionSetIPv4DstAddr = action.actionSetIPv4DstAddr();
-		    ActionSetIpToS actionSetIpToS = action.actionSetIpToS();
-		    ActionSetTcpUdpPort actionSetTcpUdpSrcPort = action.actionSetTcpUdpSrcPort();
-		    ActionSetTcpUdpPort actionSetTcpUdpDstPort = action.actionSetTcpUdpDstPort();
-		    ActionEnqueue actionEnqueue = action.actionEnqueue();
-
-		    if (actionOutput != null) {
-				actionOutputPort = actionOutput.port().value();
-				// XXX: The max length is hard-coded for now
-				OFActionOutput ofa =
-				    new OFActionOutput(actionOutput.port().value(),
-						       (short)0xffff);
-				openFlowActions.add(ofa);
-				actionsLen += ofa.getLength();
-		    }
-
-		    if (actionSetVlanId != null) {
-				OFActionVirtualLanIdentifier ofa =
-				    new OFActionVirtualLanIdentifier(actionSetVlanId.vlanId());
-				openFlowActions.add(ofa);
-				actionsLen += ofa.getLength();
-		    }
-
-		    if (actionSetVlanPriority != null) {
-				OFActionVirtualLanPriorityCodePoint ofa =
-				    new OFActionVirtualLanPriorityCodePoint(actionSetVlanPriority.vlanPriority());
-				openFlowActions.add(ofa);
-				actionsLen += ofa.getLength();
-		    }
-
-		    if (actionStripVlan != null) {
-				if (actionStripVlan.stripVlan() == true) {
-				    OFActionStripVirtualLan ofa = new OFActionStripVirtualLan();
-				    openFlowActions.add(ofa);
-				    actionsLen += ofa.getLength();
-				}
-		    }
-
-		    if (actionSetEthernetSrcAddr != null) {
-				OFActionDataLayerSource ofa = 
-				    new OFActionDataLayerSource(actionSetEthernetSrcAddr.addr().toBytes());
-				openFlowActions.add(ofa);
-				actionsLen += ofa.getLength();
-		    }
-
-		    if (actionSetEthernetDstAddr != null) {
-				OFActionDataLayerDestination ofa =
-				    new OFActionDataLayerDestination(actionSetEthernetDstAddr.addr().toBytes());
-				openFlowActions.add(ofa);
-				actionsLen += ofa.getLength();
-		    }
-
-		    if (actionSetIPv4SrcAddr != null) {
-				OFActionNetworkLayerSource ofa =
-				    new OFActionNetworkLayerSource(actionSetIPv4SrcAddr.addr().value());
-				openFlowActions.add(ofa);
-				actionsLen += ofa.getLength();
-		    }
-
-		    if (actionSetIPv4DstAddr != null) {
-				OFActionNetworkLayerDestination ofa =
-				    new OFActionNetworkLayerDestination(actionSetIPv4DstAddr.addr().value());
-				openFlowActions.add(ofa);
-				actionsLen += ofa.getLength();
-		    }
-
-		    if (actionSetIpToS != null) {
-				OFActionNetworkTypeOfService ofa =
-				    new OFActionNetworkTypeOfService(actionSetIpToS.ipToS());
-				openFlowActions.add(ofa);
-				actionsLen += ofa.getLength();
-		    }
-
-		    if (actionSetTcpUdpSrcPort != null) {
-				OFActionTransportLayerSource ofa =
-				    new OFActionTransportLayerSource(actionSetTcpUdpSrcPort.port());
-				openFlowActions.add(ofa);
-				actionsLen += ofa.getLength();
-		    }
-
-		    if (actionSetTcpUdpDstPort != null) {
-				OFActionTransportLayerDestination ofa =
-				    new OFActionTransportLayerDestination(actionSetTcpUdpDstPort.port());
-				openFlowActions.add(ofa);
-				actionsLen += ofa.getLength();
-		    }
-
-		    if (actionEnqueue != null) {
-				OFActionEnqueue ofa =
-				    new OFActionEnqueue(actionEnqueue.port().value(),
-							actionEnqueue.queueId());
-				openFlowActions.add(ofa);
-				actionsLen += ofa.getLength();
-		    }
-		}
-
-		fm.setIdleTimeout(FLOWMOD_DEFAULT_IDLE_TIMEOUT)
-		    .setHardTimeout(FLOWMOD_DEFAULT_HARD_TIMEOUT)
-		    .setPriority(PRIORITY_DEFAULT)
-		    .setBufferId(OFPacketOut.BUFFER_ID_NONE)
-		    .setCookie(cookie)
-		    .setCommand(flowModCommand)
-		    .setMatch(match)
-		    .setActions(openFlowActions)
-		    .setLengthU(OFFlowMod.MINIMUM_LENGTH + actionsLen);
-		fm.setOutPort(OFPort.OFPP_NONE.getValue());
-		if ((flowModCommand == OFFlowMod.OFPFC_DELETE) ||
-		    (flowModCommand == OFFlowMod.OFPFC_DELETE_STRICT)) {
-		    if (actionOutputPort != null)
-			fm.setOutPort(actionOutputPort);
-		}
-
-		//
-		// TODO: Set the following flag
-		// fm.setFlags(OFFlowMod.OFPFF_SEND_FLOW_REM);
-		// See method ForwardingBase::pushRoute()
-		//
-
-		//
-		// Write the message to the switch
-		//
-		log.debug("MEASUREMENT: Installing flow entry " + userState +
-			  " into switch DPID: " +
-			  sw.getStringId() +
-			  " flowEntryId: " + flowEntryId.toString() +
-			  " srcMac: " + matchSrcMac + " dstMac: " + matchDstMac +
-			  " inPort: " + matchInPort + " outPort: " + actionOutputPort
-			  );
-		add(sw,fm);
-	    //
-	    // TODO: We should use the OpenFlow Barrier mechanism
-	    // to check for errors, and update the SwitchState
-	    // for a flow entry after the Barrier message is
-	    // is received.
-	    //
-	    flowEntryObj.setSwitchState("FE_SWITCH_UPDATED");
-
 		return true;
 	}
 	
-	/**
-	 * Create OFMessage from given flow information and add it to the queue.
-	 * @param sw Switch to which message is sent.
-	 * @param flowPath FlowPath.
-	 * @param flowEntry FlowEntry.
-	 * @return true if secceed.
-	 */
 	@Override
-	public boolean add(IOFSwitch sw, FlowPath flowPath, FlowEntry flowEntry) {
+	public boolean add(IOFSwitch sw, FlowEntry flowEntry) {
 		//
 		// Create the OpenFlow Flow Modification Entry to push
 		//
@@ -706,7 +477,6 @@
 		//
 		OFMatch match = new OFMatch();
 		match.setWildcards(OFMatch.OFPFW_ALL);
-		FlowEntryMatch flowPathMatch = flowPath.flowEntryMatch();
 		FlowEntryMatch flowEntryMatch = flowEntry.flowEntryMatch();
 
 		// Match the Incoming Port
@@ -718,9 +488,6 @@
 
 		// Match the Source MAC address
 		MACAddress matchSrcMac = flowEntryMatch.srcMac();
-		if ((matchSrcMac == null) && (flowPathMatch != null)) {
-			matchSrcMac = flowPathMatch.srcMac();
-		}
 		if (matchSrcMac != null) {
 			match.setDataLayerSource(matchSrcMac.toString());
 			match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_DL_SRC);
@@ -728,9 +495,6 @@
 
 		// Match the Destination MAC address
 		MACAddress matchDstMac = flowEntryMatch.dstMac();
-		if ((matchDstMac == null) && (flowPathMatch != null)) {
-			matchDstMac = flowPathMatch.dstMac();
-		}
 		if (matchDstMac != null) {
 			match.setDataLayerDestination(matchDstMac.toString());
 			match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_DL_DST);
@@ -738,9 +502,6 @@
 
 		// Match the Ethernet Frame Type
 		Short matchEthernetFrameType = flowEntryMatch.ethernetFrameType();
-		if ((matchEthernetFrameType == null) && (flowPathMatch != null)) {
-			matchEthernetFrameType = flowPathMatch.ethernetFrameType();
-		}
 		if (matchEthernetFrameType != null) {
 			match.setDataLayerType(matchEthernetFrameType);
 			match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_DL_TYPE);
@@ -748,9 +509,6 @@
 
 		// Match the VLAN ID
 		Short matchVlanId = flowEntryMatch.vlanId();
-		if ((matchVlanId == null) && (flowPathMatch != null)) {
-			matchVlanId = flowPathMatch.vlanId();
-		}
 		if (matchVlanId != null) {
 			match.setDataLayerVirtualLan(matchVlanId);
 			match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_DL_VLAN);
@@ -758,9 +516,6 @@
 
 		// Match the VLAN priority
 		Byte matchVlanPriority = flowEntryMatch.vlanPriority();
-		if ((matchVlanPriority == null) && (flowPathMatch != null)) {
-			matchVlanPriority = flowPathMatch.vlanPriority();
-		}
 		if (matchVlanPriority != null) {
 			match.setDataLayerVirtualLanPriorityCodePoint(matchVlanPriority);
 			match.setWildcards(match.getWildcards()
@@ -769,27 +524,18 @@
 
 		// Match the Source IPv4 Network prefix
 		IPv4Net matchSrcIPv4Net = flowEntryMatch.srcIPv4Net();
-		if ((matchSrcIPv4Net == null) && (flowPathMatch != null)) {
-			matchSrcIPv4Net = flowPathMatch.srcIPv4Net();
-		}
 		if (matchSrcIPv4Net != null) {
 			match.setFromCIDR(matchSrcIPv4Net.toString(), OFMatch.STR_NW_SRC);
 		}
 
 		// Natch the Destination IPv4 Network prefix
 		IPv4Net matchDstIPv4Net = flowEntryMatch.dstIPv4Net();
-		if ((matchDstIPv4Net == null) && (flowPathMatch != null)) {
-			matchDstIPv4Net = flowPathMatch.dstIPv4Net();
-		}
 		if (matchDstIPv4Net != null) {
 			match.setFromCIDR(matchDstIPv4Net.toString(), OFMatch.STR_NW_DST);
 		}
 
 		// Match the IP protocol
 		Byte matchIpProto = flowEntryMatch.ipProto();
-		if ((matchIpProto == null) && (flowPathMatch != null)) {
-			matchIpProto = flowPathMatch.ipProto();
-		}
 		if (matchIpProto != null) {
 			match.setNetworkProtocol(matchIpProto);
 			match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_NW_PROTO);
@@ -797,9 +543,6 @@
 
 		// Match the IP ToS (DSCP field, 6 bits)
 		Byte matchIpToS = flowEntryMatch.ipToS();
-		if ((matchIpToS == null) && (flowPathMatch != null)) {
-			matchIpToS = flowPathMatch.ipToS();
-		}
 		if (matchIpToS != null) {
 			match.setNetworkTypeOfService(matchIpToS);
 			match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_NW_TOS);
@@ -807,9 +550,6 @@
 
 		// Match the Source TCP/UDP port
 		Short matchSrcTcpUdpPort = flowEntryMatch.srcTcpUdpPort();
-		if ((matchSrcTcpUdpPort == null) && (flowPathMatch != null)) {
-			matchSrcTcpUdpPort = flowPathMatch.srcTcpUdpPort();
-		}
 		if (matchSrcTcpUdpPort != null) {
 			match.setTransportSource(matchSrcTcpUdpPort);
 			match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_TP_SRC);
@@ -817,9 +557,6 @@
 
 		// Match the Destination TCP/UDP port
 		Short matchDstTcpUdpPort = flowEntryMatch.dstTcpUdpPort();
-		if ((matchDstTcpUdpPort == null) && (flowPathMatch != null)) {
-			matchDstTcpUdpPort = flowPathMatch.dstTcpUdpPort();
-		}
 		if (matchDstTcpUdpPort != null) {
 			match.setTransportDestination(matchDstTcpUdpPort);
 			match.setWildcards(match.getWildcards() & ~OFMatch.OFPFW_TP_DST);
@@ -965,7 +702,7 @@
 		//
 		// Write the message to the switch
 		//
-		log.debug("MEASUREMENT: Installing flow entry "
+		log.debug("Installing flow entry "
 				+ flowEntry.flowEntryUserState() + " into switch DPID: "
 				+ sw.getStringId() + " flowEntryId: "
 				+ flowEntry.flowEntryId().toString() + " srcMac: "
@@ -984,8 +721,59 @@
 		
 		return add(sw,fm);
 	}
+	
+	@Override
+	public OFBarrierReply barrier(IOFSwitch sw) {
+		OFMessageFuture<OFBarrierReply> future = barrierAsync(sw);
+		if (future == null) {
+			return null;
+		}
+		
+		try {
+			return future.get();
+		} catch (InterruptedException e) {
+			e.printStackTrace();
+			log.error("InterruptedException: {}", e);
+			return null;
+		} catch (ExecutionException e) {
+			e.printStackTrace();
+			log.error("ExecutionException: {}", e);
+			return null;
+		}
+	}
 
-	private SwitchQueue getQueue(IOFSwitch sw) {
+	@Override
+	public OFBarrierReplyFuture barrierAsync(IOFSwitch sw) {
+		// TODO creation of message and future should be moved to OFSwitchImpl
+
+		if (sw == null) {
+			return null;
+		}
+		
+		OFBarrierRequest msg = (OFBarrierRequest) factory.getMessage(OFType.BARRIER_REQUEST);
+		msg.setXid(sw.getNextTransactionId());
+
+		OFBarrierReplyFuture future = new OFBarrierReplyFuture(threadPool, sw, msg.getXid());
+		synchronized (barrierFutures) {
+			Map<Integer,OFBarrierReplyFuture> map = barrierFutures.get(sw.getId());
+			if (map == null) {
+				map = new HashMap<Integer,OFBarrierReplyFuture>();
+				barrierFutures.put(sw.getId(), map);
+			}
+			map.put(msg.getXid(), future);
+		}
+		
+		add(sw, msg);
+		
+		return future;
+	}
+
+	/**
+	 * Get a queue attached to a switch.
+	 * @param sw Switch object
+	 * @return Queue object
+	 */
+	protected SwitchQueue getQueue(IOFSwitch sw) {
 		if (sw == null)  {
 			return null;
 		}
@@ -993,14 +781,61 @@
 		return getProcess(sw).queues.get(sw);
 	}
 	
-	private long getHash(IOFSwitch sw) {
-		// TODO should consider equalization algorithm
+	/**
+	 * Get a hash value correspondent to a switch.
+	 * @param sw Switch object
+	 * @return Hash value
+	 */
+	protected long getHash(IOFSwitch sw) {
+		// This code assumes DPID is sequentially assigned.
+		// TODO consider equalization algorithm
 		return sw.getId() % number_thread;
 	}
-	
-	private FlowPusherProcess getProcess(IOFSwitch sw) {
+
+	/**
+	 * Get a Thread object which processes the queue attached to a switch.
+	 * @param sw Switch object
+	 * @return Thread object
+	 */
+	protected FlowPusherThread getProcess(IOFSwitch sw) {
 		long hash = getHash(sw);
 		
 		return threadMap.get(hash);
 	}
+
+	@Override
+	public String getName() {
+		return "flowpusher";
+	}
+
+	@Override
+	public boolean isCallbackOrderingPrereq(OFType type, String name) {
+		return false;
+	}
+
+	@Override
+	public boolean isCallbackOrderingPostreq(OFType type, String name) {
+		return false;
+	}
+
+	@Override
+	public Command receive(IOFSwitch sw, OFMessage msg, FloodlightContext cntx) {
+		Map<Integer,OFBarrierReplyFuture> map = barrierFutures.get(sw.getId());
+		if (map == null) {
+			log.debug("null map for {} : {}", sw.getId(), barrierFutures);
+			return Command.CONTINUE;
+		}
+		
+		OFBarrierReplyFuture future = map.get(msg.getXid());
+		if (future == null) {
+			log.debug("null future for {} : {}", msg.getXid(), map);
+			return Command.CONTINUE;
+		}
+		
+		log.debug("Received BARRIER_REPLY : {}", msg);
+		future.deliverFuture(sw, msg);
+		
+		return Command.CONTINUE;
+	}
+
 }
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowSynchronizer.java b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowSynchronizer.java
index b2e4552..c357e7c 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowSynchronizer.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowSynchronizer.java
@@ -2,7 +2,6 @@
 
 import java.io.IOException;
 import java.util.ArrayList;
-import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
@@ -13,23 +12,8 @@
 
 import org.openflow.protocol.OFFlowMod;
 import org.openflow.protocol.OFMatch;
-import org.openflow.protocol.OFMessage;
-import org.openflow.protocol.OFPacketOut;
 import org.openflow.protocol.OFPort;
 import org.openflow.protocol.OFStatisticsRequest;
-import org.openflow.protocol.action.OFAction;
-import org.openflow.protocol.action.OFActionDataLayerDestination;
-import org.openflow.protocol.action.OFActionDataLayerSource;
-import org.openflow.protocol.action.OFActionEnqueue;
-import org.openflow.protocol.action.OFActionNetworkLayerDestination;
-import org.openflow.protocol.action.OFActionNetworkLayerSource;
-import org.openflow.protocol.action.OFActionNetworkTypeOfService;
-import org.openflow.protocol.action.OFActionOutput;
-import org.openflow.protocol.action.OFActionStripVirtualLan;
-import org.openflow.protocol.action.OFActionTransportLayerDestination;
-import org.openflow.protocol.action.OFActionTransportLayerSource;
-import org.openflow.protocol.action.OFActionVirtualLanIdentifier;
-import org.openflow.protocol.action.OFActionVirtualLanPriorityCodePoint;
 import org.openflow.protocol.statistics.OFFlowStatisticsReply;
 import org.openflow.protocol.statistics.OFFlowStatisticsRequest;
 import org.openflow.protocol.statistics.OFStatistics;
@@ -37,107 +21,70 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import com.google.common.collect.Lists;
-import com.tinkerpop.blueprints.Direction;
-
-import net.floodlightcontroller.core.IFloodlightProviderService;
 import net.floodlightcontroller.core.IOFSwitch;
-import net.floodlightcontroller.core.IOFSwitchListener;
-import net.floodlightcontroller.core.module.FloodlightModuleContext;
-import net.floodlightcontroller.core.module.FloodlightModuleException;
-import net.floodlightcontroller.core.module.IFloodlightModule;
-import net.floodlightcontroller.core.module.IFloodlightService;
-import net.floodlightcontroller.restserver.IRestApiService;
-import net.onrc.onos.datagrid.IDatagridService;
 import net.onrc.onos.graph.GraphDBOperation;
 import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IFlowEntry;
 import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.ISwitchObject;
-import net.onrc.onos.ofcontroller.core.module.IOnosService;
-import net.onrc.onos.ofcontroller.floodlightlistener.INetworkGraphService;
+import net.onrc.onos.ofcontroller.flowmanager.FlowDatabaseOperation;
 import net.onrc.onos.ofcontroller.util.Dpid;
-import net.onrc.onos.ofcontroller.util.FlowEntryAction;
-import net.onrc.onos.ofcontroller.util.FlowEntryActions;
+import net.onrc.onos.ofcontroller.util.FlowEntry;
 import net.onrc.onos.ofcontroller.util.FlowEntryId;
-import net.onrc.onos.ofcontroller.util.FlowEntryAction.ActionEnqueue;
-import net.onrc.onos.ofcontroller.util.FlowEntryAction.ActionOutput;
-import net.onrc.onos.ofcontroller.util.FlowEntryAction.ActionSetEthernetAddr;
-import net.onrc.onos.ofcontroller.util.FlowEntryAction.ActionSetIPv4Addr;
-import net.onrc.onos.ofcontroller.util.FlowEntryAction.ActionSetIpToS;
-import net.onrc.onos.ofcontroller.util.FlowEntryAction.ActionSetTcpUdpPort;
-import net.onrc.onos.ofcontroller.util.FlowEntryAction.ActionSetVlanId;
-import net.onrc.onos.ofcontroller.util.FlowEntryAction.ActionSetVlanPriority;
-import net.onrc.onos.ofcontroller.util.FlowEntryAction.ActionStripVlan;
-import net.onrc.onos.registry.controller.IControllerRegistryService;
 
-public class FlowSynchronizer implements IFlowSyncService, IOFSwitchListener {
+/**
+ * FlowSynchronizer is an implementation of FlowSyncService.
+ * In addition to IFlowSyncService, FlowSynchronizer periodically reads flow
+ * tables from switches and compare them with GraphDB to drop unnecessary
+ * flows and/or to install missing flows.
+ * @author Brian
+ *
+ */
+public class FlowSynchronizer implements IFlowSyncService {
 
-    protected static Logger log = LoggerFactory.getLogger(FlowSynchronizer.class);
-    protected IFloodlightProviderService floodlightProvider;
-    protected IControllerRegistryService registryService;
-    protected IFlowPusherService pusher;
+    private static Logger log = LoggerFactory.getLogger(FlowSynchronizer.class);
 
     private GraphDBOperation dbHandler;
-    private Map<IOFSwitch, Thread> switchThread = new HashMap<IOFSwitch, Thread>();
+    protected IFlowPusherService pusher;
+    private Map<IOFSwitch, Thread> switchThreads; 
 
     public FlowSynchronizer() {
 	dbHandler = new GraphDBOperation("");
+	switchThreads = new HashMap<IOFSwitch, Thread>();
     }
 
+    @Override
     public void synchronize(IOFSwitch sw) {
-	Synchroizer sync = new Synchroizer(sw);
+	Synchronizer sync = new Synchronizer(sw);
 	Thread t = new Thread(sync);
+	switchThreads.put(sw, t);
 	t.start();
-	switchThread.put(sw, t);
     }
-
+    
     @Override
-    public void addedSwitch(IOFSwitch sw) {
-	log.debug("Switch added: {}", sw.getId());
-
-	if (registryService.hasControl(sw.getId())) {
-	    synchronize(sw);
-	}
-    }
-
-    @Override
-    public void removedSwitch(IOFSwitch sw) {
-	log.debug("Switch removed: {}", sw.getId());
-
-	Thread t = switchThread.remove(sw);
+    public void interrupt(IOFSwitch sw) {
+	Thread t = switchThreads.remove(sw);
 	if(t != null) {
 	    t.interrupt();
-	}
-
+	}	
     }
 
-    @Override
-    public void switchPortChanged(Long switchId) {
-	// TODO Auto-generated method stub
+    /**
+     * Initialize Synchronizer.
+     * @param pusherService FlowPusherService used for sending messages.
+     */
+    public void init(IFlowPusherService pusherService) {
+	pusher = pusherService;
     }
 
-    @Override
-    public String getName() {
-	return "FlowSynchronizer";
-    }
-
-    //@Override
-    public void init(FloodlightModuleContext context)
-	    throws FloodlightModuleException {
-	floodlightProvider = context.getServiceImpl(IFloodlightProviderService.class);
-	registryService = context.getServiceImpl(IControllerRegistryService.class);
-	pusher = context.getServiceImpl(IFlowPusherService.class);
-    }
-
-    //@Override
-    public void startUp(FloodlightModuleContext context) {
-	floodlightProvider.addOFSwitchListener(this);
-    }
-
-    protected class Synchroizer implements Runnable {
+    /**
+     * Synchronizer represents main thread of synchronization.
+     * @author Brian
+     *
+     */
+	protected class Synchronizer implements Runnable {
 	IOFSwitch sw;
 	ISwitchObject swObj;
 
-	public Synchroizer(IOFSwitch sw) {
+	public Synchronizer(IOFSwitch sw) {
 	    this.sw = sw;
 	    Dpid dpid = new Dpid(sw.getId());
 	    this.swObj = dbHandler.searchSwitch(dpid.toString());
@@ -145,11 +92,21 @@
 
 	@Override
 	public void run() {
+	    // TODO: stop adding other flow entries while synchronizing
+	    //pusher.suspend(sw);
 	    Set<FlowEntryWrapper> graphEntries = getFlowEntriesFromGraph();
 	    Set<FlowEntryWrapper> switchEntries = getFlowEntriesFromSwitch();
 	    compare(graphEntries, switchEntries);
+	    //pusher.resume(sw);
 	}
 
+	/**
+	 * Compare flows entries in GraphDB and switch to pick up necessary
+	 * messages.
+	 * After picking up, picked messages are added to FlowPusher.
+	 * @param graphEntries Flow entries in GraphDB.
+	 * @param switchEntries Flow entries in switch.
+	 */
 	private void compare(Set<FlowEntryWrapper> graphEntries, Set<FlowEntryWrapper> switchEntries) {
 	    int added = 0, removed = 0, skipped = 0;
 	    for(FlowEntryWrapper entry : switchEntries) {
@@ -173,6 +130,10 @@
 		      "Flow entries skipped " + skipped);
 	}
 
+	/**
+	 * Read GraphDB to get FlowEntries associated with a switch.
+	 * @return set of FlowEntries
+	 */
 	private Set<FlowEntryWrapper> getFlowEntriesFromGraph() {
 	    Set<FlowEntryWrapper> entries = new HashSet<FlowEntryWrapper>();
 	    for(IFlowEntry entry : swObj.getFlowEntries()) {
@@ -182,6 +143,10 @@
 	    return entries;	    
 	}
 
+	/**
+	 * Read flow table from switch and derive FlowEntries from table.
+	 * @return set of FlowEntries
+	 */
 	private Set<FlowEntryWrapper> getFlowEntriesFromSwitch() {
 
 	    int lengthU = 0;
@@ -228,48 +193,83 @@
 
     }
 
+    /**
+     * FlowEntryWrapper represents abstract FlowEntry which is embodied
+     * by FlowEntryId (from GraphDB) or OFFlowStatisticsReply (from switch).
+     * @author Brian
+     *
+     */
     class FlowEntryWrapper {
-	FlowEntryId id;
-	IFlowEntry iflowEntry;
+	FlowEntryId flowEntryId;
 	OFFlowStatisticsReply statisticsReply;
 
 	public FlowEntryWrapper(IFlowEntry entry) {
-	    iflowEntry = entry;
-	    id = new FlowEntryId(entry.getFlowEntryId());
+	    flowEntryId = new FlowEntryId(entry.getFlowEntryId());
 	}
 
 	public FlowEntryWrapper(OFFlowStatisticsReply entry) {
+	    flowEntryId = new FlowEntryId(entry.getCookie());
 	    statisticsReply = entry;
-	    id = new FlowEntryId(entry.getCookie());
 	}
 
+	/**
+	 * Install this FlowEntry to a switch via FlowPusher.
+	 * @param sw Switch to which flow will be installed.
+	 */
 	public void addToSwitch(IOFSwitch sw) {
-	    if(iflowEntry != null) {
-		pusher.add(sw, iflowEntry.getFlow(), iflowEntry);
-	    }
-	    else if(statisticsReply != null) {
-		log.error("Adding existing flow entry {} to sw {}", 
+	    if (statisticsReply != null) {
+		log.error("Error adding existing flow entry {} to sw {}", 
 			  statisticsReply.getCookie(), sw.getId());
+		return;
 	    }
+
+	    // Get the Flow Entry state from the Network Graph
+	    IFlowEntry iFlowEntry = null;
+	    try {
+		iFlowEntry = dbHandler.searchFlowEntry(flowEntryId);
+	    } catch (Exception e) {
+		log.error("Error finding flow entry {} in Network Graph",
+			  flowEntryId);
+		return;
+	    }
+	    if (iFlowEntry == null) {
+		log.error("Cannot add flow entry {} to sw {} : flow entry not found",
+			  flowEntryId, sw.getId());
+		return;
+	    }
+
+	    FlowEntry flowEntry =
+		FlowDatabaseOperation.extractFlowEntry(iFlowEntry);
+	    if (flowEntry == null) {
+		log.error("Cannot add flow entry {} to sw {} : flow entry cannot be extracted",
+			  flowEntryId, sw.getId());
+		return;
+	    }
+
+	    pusher.add(sw, flowEntry);
 	}
 	
-	public void removeFromSwitch(IOFSwitch sw){
-	    if(iflowEntry != null) {
-		log.error("Removing non-existent flow entry {} from sw {}", 
-			  iflowEntry.getFlowEntryId(), sw.getId());
+	/**
+	 * Remove this FlowEntry from a switch via FlowPusher.
+	 * @param sw Switch from which flow will be removed.
+	 */
+	public void removeFromSwitch(IOFSwitch sw) {
+	    if (statisticsReply == null) {
+		log.error("Error removing non-existent flow entry {} from sw {}", 
+			  flowEntryId, sw.getId());
+		return;
+	    }
 
-	    }
-	    else if(statisticsReply != null) {
-		// Convert Statistics Reply to Flow Mod, then write it
-		OFFlowMod fm = new OFFlowMod();
-		fm.setCookie(statisticsReply.getCookie());
-		fm.setCommand(OFFlowMod.OFPFC_DELETE_STRICT);
-		fm.setLengthU(OFFlowMod.MINIMUM_LENGTH);
-		fm.setMatch(statisticsReply.getMatch());
-		fm.setPriority(statisticsReply.getPriority());
-		fm.setOutPort(OFPort.OFPP_NONE);
-		pusher.add(sw, fm);
-	    }
+	    // Convert Statistics Reply to Flow Mod, then write it
+	    OFFlowMod fm = new OFFlowMod();
+	    fm.setCookie(statisticsReply.getCookie());
+	    fm.setCommand(OFFlowMod.OFPFC_DELETE_STRICT);
+	    fm.setLengthU(OFFlowMod.MINIMUM_LENGTH);
+	    fm.setMatch(statisticsReply.getMatch());
+	    fm.setPriority(statisticsReply.getPriority());
+	    fm.setOutPort(OFPort.OFPP_NONE);
+
+	    pusher.add(sw, fm);
 	}
 
 	/**
@@ -277,7 +277,7 @@
 	 */
 	@Override
 	public int hashCode() {
-	    return id.hashCode();
+	    return flowEntryId.hashCode();
 	}
 
 	/**
@@ -285,22 +285,21 @@
 	 * the same value; otherwise, returns false.
 	 * 
 	 * @param Object to compare
+	 * @return true if the object has the same Flow Entry ID.
 	 */
 	@Override
 	public boolean equals(Object obj){
 	    if(obj.getClass() == this.getClass()) {
 		FlowEntryWrapper entry = (FlowEntryWrapper) obj;
 		// TODO: we need to actually compare the match + actions
-		return this.id.equals(entry.id);
+		return this.flowEntryId.equals(entry.flowEntryId);
 	    }
 	    return false;
 	}
 
 	@Override
 	public String toString() {
-	    return id.toString();
+	    return flowEntryId.toString();
 	}
     }
 }
-
-
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/IFlowPusherService.java b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/IFlowPusherService.java
index e16dd20..2f550a7 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/IFlowPusherService.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/IFlowPusherService.java
@@ -1,43 +1,105 @@
 package net.onrc.onos.ofcontroller.flowprogrammer;
 
-import net.floodlightcontroller.core.IOFSwitch;
-import net.floodlightcontroller.core.module.IFloodlightService;
-import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IFlowEntry;
-import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IFlowPath;
-import net.onrc.onos.ofcontroller.util.FlowEntry;
-import net.onrc.onos.ofcontroller.util.FlowPath;
-
+import org.openflow.protocol.OFBarrierReply;
 import org.openflow.protocol.OFMessage;
 
+import net.floodlightcontroller.core.IOFSwitch;
+import net.floodlightcontroller.core.internal.OFMessageFuture;
+import net.floodlightcontroller.core.module.IFloodlightService;
+import net.onrc.onos.ofcontroller.util.FlowEntry;
+
+/**
+ * FlowPusherService is a service to send message to switches in proper rate.
+ * Conceptually a queue is attached to each switch, and FlowPusherService
+ * read a message from queue and send it to switch in order.
+ * To guarantee message has been installed, FlowPusherService can add barrier
+ * message to queue and can notify when barrier message is sent to switch.
+ * @author Naoki Shiota
+ *
+ */
 public interface IFlowPusherService extends IFloodlightService {
 	/**
-	 * Add a message to the queue of a switch.
-	 * @param sw
-	 * @param msg
-	 * @return
+	 * Create a queue correspondent to the switch.
+	 * @param sw Switch to which new queue is attached.
+	 * @return true if new queue is successfully created.
+	 */
+	boolean createQueue(IOFSwitch sw);
+
+	/**
+	 * Delete a queue correspondent to the switch.
+	 * Messages remains in queue will be all sent before queue is deleted.
+	 * @param sw Switch of which queue is deleted.
+	 * @return true if queue is successfully deleted.
+	 */
+	boolean deleteQueue(IOFSwitch sw);
+	
+	/**
+	 * Delete a queue correspondent to the switch.
+	 * By setting force flag on, queue will be deleted immediately.
+	 * @param sw Switch of which queue is deleted.
+	 * @param forceStop If this flag is set to true, queue will be deleted
+	 *        immediately regardless of any messages in the queue.
+	 *        If false, all messages will be sent to switch and queue will
+	 *        be deleted after that.
+	 * @return true if queue is successfully deleted or flagged to be deleted.
+	 */
+	boolean deleteQueue(IOFSwitch sw, boolean forceStop);
+	
+	/**
+	 * Add a message to the queue of the switch.
+	 * @param sw Switch to which message is pushed.
+	 * @param msg Message object to be added.
+	 * @return true if message is successfully added to a queue.
 	 */
 	boolean add(IOFSwitch sw, OFMessage msg);
-	boolean add(IOFSwitch sw, FlowPath flowPath, FlowEntry flowEntry);
-	boolean add(IOFSwitch sw, IFlowPath flowObj, IFlowEntry flowEntryObj);
+
+	/**
+	 * Create a message from FlowEntry and add it to the queue of the switch.
+	 * @param sw Switch to which message is pushed.
+	 * @param flowEntry FlowEntry object used for creating message.
+	 * @return true if message is successfully added to a queue.
+	 */
+	boolean add(IOFSwitch sw, FlowEntry flowEntry);
+
+	/**
+	 * Set sending rate to a switch.
+	 * @param sw Switch.
+	 * @param rate Rate in bytes/ms.
+	 */
+	public void setRate(IOFSwitch sw, long rate);
+	
+	/**
+	 * Add BARRIER message to queue and wait for reply.
+	 * @param sw Switch to which barrier message is pushed.
+	 * @return BARRIER_REPLY message sent from switch.
+	 */
+	OFBarrierReply barrier(IOFSwitch sw);
+	
+	/**
+	 * Add BARRIER message to queue asynchronously.
+	 * @param sw Switch to which barrier message is pushed.
+	 * @return Future object of BARRIER_REPLY message which will be sent from switch.
+	 */
+	OFMessageFuture<OFBarrierReply> barrierAsync(IOFSwitch sw);
 	
 	/**
 	 * Suspend pushing message to a switch.
-	 * @param sw
+	 * @param sw Switch to be suspended pushing message.
 	 * @return true if success
 	 */
 	boolean suspend(IOFSwitch sw);
 	
 	/**
 	 * Resume pushing message to a switch.
-	 * @param sw
+	 * @param sw Switch to be resumed pushing message.
 	 * @return true if success
 	 */
 	boolean resume(IOFSwitch sw);
 	
 	/**
 	 * Get whether pushing of message is suspended or not.
-	 * @param sw
-	 * @return true if suspended
+	 * @param sw Switch to be checked.
+	 * @return true if suspended.
 	 */
 	boolean isSuspended(IOFSwitch sw);
 }
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/IFlowSyncService.java b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/IFlowSyncService.java
index 1e71f6a..4e6efaf 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/IFlowSyncService.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/IFlowSyncService.java
@@ -5,9 +5,13 @@
 import net.floodlightcontroller.core.module.IFloodlightService;
 
 /**
- * @author bocon
+ * FlowSyncService is a service to synchronize GraphDB and switch's flow table.
+ * FlowSyncService offers APIs to trigger and interrupt synchronization explicitly.
+ * @author Brian
  *
  */
 public interface IFlowSyncService extends IFloodlightService {
     public void synchronize(IOFSwitch sw);
+    
+    public void interrupt(IOFSwitch sw);
 }
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/OFBarrierReplyFuture.java b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/OFBarrierReplyFuture.java
new file mode 100644
index 0000000..3013f5a
--- /dev/null
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/OFBarrierReplyFuture.java
@@ -0,0 +1,49 @@
+package net.onrc.onos.ofcontroller.flowprogrammer;
+
+import java.util.concurrent.TimeUnit;
+
+import org.openflow.protocol.OFBarrierReply;
+import org.openflow.protocol.OFMessage;
+import org.openflow.protocol.OFType;
+
+import net.floodlightcontroller.core.IOFSwitch;
+import net.floodlightcontroller.core.internal.OFMessageFuture;
+import net.floodlightcontroller.threadpool.IThreadPoolService;
+
+public class OFBarrierReplyFuture extends OFMessageFuture<OFBarrierReply> {
+
+    protected volatile boolean finished;
+
+    public OFBarrierReplyFuture(IThreadPoolService tp,
+            IOFSwitch sw, int transactionId) {
+        super(tp, sw, OFType.FEATURES_REPLY, transactionId);
+        init();
+    }
+
+    public OFBarrierReplyFuture(IThreadPoolService tp,
+            IOFSwitch sw, int transactionId, long timeout, TimeUnit unit) {
+        super(tp, sw, OFType.FEATURES_REPLY, transactionId, timeout, unit);
+        init();
+    }
+
+    private void init() {
+        this.finished = false;
+        this.result = null;
+    }
+
+    @Override
+    protected void handleReply(IOFSwitch sw, OFMessage msg) {
+        this.result = (OFBarrierReply) msg;
+        this.finished = true;
+    }
+
+    @Override
+    protected boolean isFinished() {
+        return finished;
+    }
+
+    @Override
+    protected void unRegister() {
+        super.unRegister();
+    }
+}
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/FlowProgrammerWebRoutable.java b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/FlowProgrammerWebRoutable.java
new file mode 100644
index 0000000..00d7fc9
--- /dev/null
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/FlowProgrammerWebRoutable.java
@@ -0,0 +1,26 @@
+package net.onrc.onos.ofcontroller.flowprogrammer.web;
+
+import org.restlet.Context;
+import org.restlet.Restlet;
+import org.restlet.routing.Router;
+
+import net.floodlightcontroller.restserver.RestletRoutable;
+
+public class FlowProgrammerWebRoutable implements RestletRoutable {
+
+	@Override
+	public Restlet getRestlet(Context context) {
+		Router router = new Router(context);
+		router.attach("/pusher/setrate/{dpid}/{rate}/json", SetPushRateResource.class);
+		router.attach("/pusher/suspend/{dpid}/json", SuspendPusherResource.class);
+		router.attach("/pusher/resume/{dpid}/json", ResumePusherResource.class);
+		router.attach("/pusher/barrier/{dpid}/json", SendBarrierResource.class);
+		return router;
+	}
+
+	@Override
+	public String basePath() {
+		return "/wm/fprog";
+	}
+
+}
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/PusherResource.java b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/PusherResource.java
new file mode 100644
index 0000000..4e1c0fc
--- /dev/null
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/PusherResource.java
@@ -0,0 +1,33 @@
+package net.onrc.onos.ofcontroller.flowprogrammer.web;
+
+import org.restlet.resource.ServerResource;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import net.floodlightcontroller.core.IFloodlightProviderService;
+import net.onrc.onos.ofcontroller.flowprogrammer.IFlowPusherService;
+
+public class PusherResource extends ServerResource {
+    protected final static Logger log = LoggerFactory.getLogger(PusherResource.class);
+
+    protected IFloodlightProviderService provider;
+	protected IFlowPusherService pusher;
+	
+	protected boolean init() {
+    	provider = (IFloodlightProviderService)
+    			getContext().getAttributes().
+    			get(IFloodlightProviderService.class.getCanonicalName());
+    	if (provider == null) {
+		    log.debug("ONOS FloodlightProvider not found");
+		    return false;
+		}
+    	
+    	pusher = (IFlowPusherService)getContext().getAttributes().
+    			get(IFlowPusherService.class.getCanonicalName());
+    	if (pusher == null) {
+		    log.debug("ONOS FlowPusherService not found");
+		    return false;
+		}
+    	return true;
+	}
+}
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/ResumePusherResource.java b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/ResumePusherResource.java
new file mode 100644
index 0000000..dcbe3e9
--- /dev/null
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/ResumePusherResource.java
@@ -0,0 +1,41 @@
+package net.onrc.onos.ofcontroller.flowprogrammer.web;
+
+import net.floodlightcontroller.core.IOFSwitch;
+
+import org.openflow.util.HexString;
+import org.restlet.resource.Get;
+
+/**
+ * FlowProgrammer REST API implementation: Resume sending message to switch.
+ *
+ *   GET /wm/fprog/pusher/resume/{dpid}/json"
+ */
+public class ResumePusherResource extends PusherResource {
+    /**
+     * Implement the API.
+     *
+     * @return true if succeeded, false if failed.
+     */
+    @Get("json")
+    public boolean retrieve() {
+    	if (! init()) {
+    		return false;
+    	}
+    	
+    	long dpid;
+    	try {
+    		dpid = HexString.toLong((String)getRequestAttributes().get("dpid"));
+    	} catch (NumberFormatException e) {
+    		log.error("Invalid number format");
+    		return false;
+    	}
+
+    	IOFSwitch sw = provider.getSwitches().get(dpid);
+    	if (sw == null) {
+    		log.error("Invalid dpid");
+    		return false;
+    	}
+    	
+    	return pusher.resume(sw);
+    }
+}
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/SendBarrierResource.java b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/SendBarrierResource.java
new file mode 100644
index 0000000..33b666a
--- /dev/null
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/SendBarrierResource.java
@@ -0,0 +1,41 @@
+package net.onrc.onos.ofcontroller.flowprogrammer.web;
+
+import net.floodlightcontroller.core.IOFSwitch;
+
+import org.openflow.protocol.OFBarrierReply;
+import org.openflow.util.HexString;
+import org.restlet.resource.Get;
+
+/**
+ * FlowProgrammer REST API implementation: Send barrier message to switch.
+ *
+ *   GET /wm/fprog/pusher/barrier/{dpid}/json"
+ */
+public class SendBarrierResource extends PusherResource {
+    /**
+     * Implement the API.
+     *
+     * @return true if succeeded, false if failed.
+     */
+    @Get("json")
+    public OFBarrierReply retrieve() {
+    	if (! init()) {
+    		return null;
+    	}
+    	long dpid;
+    	try {
+    		dpid = HexString.toLong((String)getRequestAttributes().get("dpid"));
+    	} catch (NumberFormatException e) {
+    		log.error("Invalid number format");
+    		return null;
+    	}
+
+    	IOFSwitch sw = provider.getSwitches().get(dpid);
+    	if (sw == null) {
+    		log.error("Invalid dpid");
+    		return null;
+    	}
+    	
+    	return pusher.barrier(sw);
+    }
+}
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/SetPushRateResource.java b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/SetPushRateResource.java
new file mode 100644
index 0000000..9431d65
--- /dev/null
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/SetPushRateResource.java
@@ -0,0 +1,47 @@
+package net.onrc.onos.ofcontroller.flowprogrammer.web;
+
+import net.floodlightcontroller.core.IOFSwitch;
+
+import org.openflow.util.HexString;
+import org.restlet.resource.Get;
+
+/**
+ * FlowProgrammer REST API implementation: Set sending rate to the switch.
+ *
+ *   GET /wm/fprog/pusher/setrate/{dpid}/{rate}/json"
+ */
+public class SetPushRateResource extends PusherResource {
+
+    /**
+     * Implement the API.
+     *
+     * @return true if succeeded, false if failed.
+     */
+    @Get("json")
+    public boolean retrieve() {
+    	if (! init()) {
+    		return false;
+    	}
+    	
+    	long dpid;
+    	long rate;
+    	
+    	try {
+    		dpid = HexString.toLong((String)getRequestAttributes().get("dpid"));
+        	rate = Long.valueOf((String)getRequestAttributes().get("rate"));
+    	} catch (NumberFormatException e) {
+    		log.error("Invalid number format");
+    		return false;
+    	}
+
+    	IOFSwitch sw = provider.getSwitches().get(dpid);
+    	if (sw == null) {
+    		log.error("Invalid dpid");
+    		return false;
+    	}
+    	
+    	pusher.setRate(sw, rate);
+    	
+    	return true;
+    }
+}
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/SuspendPusherResource.java b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/SuspendPusherResource.java
new file mode 100644
index 0000000..1a5266b
--- /dev/null
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/SuspendPusherResource.java
@@ -0,0 +1,46 @@
+package net.onrc.onos.ofcontroller.flowprogrammer.web;
+
+import net.floodlightcontroller.core.IOFSwitch;
+
+import org.openflow.util.HexString;
+import org.restlet.resource.Get;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * FlowProgrammer REST API implementation: Suspend sending message to switch.
+ *
+ *   GET /wm/fprog/pusher/suspend/{dpid}/json"
+ */
+public class SuspendPusherResource extends PusherResource {
+
+    protected final static Logger log = LoggerFactory.getLogger(SetPushRateResource.class);
+
+    /**
+     * Implement the API.
+     *
+     * @return true if succeeded, false if failed.
+     */
+    @Get("json")
+    public boolean retrieve() {
+    	if (! init()) {
+    		return false;
+    	}
+    	
+    	long dpid;
+    	try {
+    		dpid = HexString.toLong((String)getRequestAttributes().get("dpid"));
+    	} catch (NumberFormatException e) {
+    		log.error("Invalid number format");
+    		return false;
+    	}
+
+    	IOFSwitch sw = provider.getSwitches().get(dpid);
+    	if (sw == null) {
+    		log.error("Invalid dpid");
+    		return false;
+    	}
+    	
+    	return pusher.suspend(sw);
+    }
+}
diff --git a/src/main/java/net/onrc/onos/ofcontroller/util/FlowEntry.java b/src/main/java/net/onrc/onos/ofcontroller/util/FlowEntry.java
index 15a6233..98dbd88 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/util/FlowEntry.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/util/FlowEntry.java
@@ -136,10 +136,11 @@
      *
      * @return true if the Flow ID is valid, otherwise false.
      */
+    @JsonIgnore
     public boolean isValidFlowId() {
 	if (this.flowId == null)
 	    return false;
-	return (this.flowId.value() != 0);
+	return (this.flowId.isValid());
     }
 
     /**
@@ -165,10 +166,11 @@
      *
      * @return true if the Flow Entry ID is valid, otherwise false.
      */
+    @JsonIgnore
     public boolean isValidFlowEntryId() {
 	if (this.flowEntryId == null)
 	    return false;
-	return (this.flowEntryId.value() != 0);
+	return (this.flowEntryId.isValid());
     }
 
     /**
diff --git a/src/main/java/net/onrc/onos/ofcontroller/util/FlowEntryActions.java b/src/main/java/net/onrc/onos/ofcontroller/util/FlowEntryActions.java
index 53aab66..7d9688b 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/util/FlowEntryActions.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/util/FlowEntryActions.java
@@ -2,6 +2,7 @@
 
 import java.util.ArrayList;
 
+import org.codehaus.jackson.annotate.JsonIgnore;
 import org.codehaus.jackson.annotate.JsonProperty;
 
 /**
@@ -79,6 +80,7 @@
      *
      * @return true if the set of actions is empty, otherwise false.
      */
+    @JsonIgnore
     public Boolean isEmpty() {
 	return actions.isEmpty();
     }
diff --git a/src/main/java/net/onrc/onos/ofcontroller/util/FlowEntryId.java b/src/main/java/net/onrc/onos/ofcontroller/util/FlowEntryId.java
index 29efe4c..f5728b0 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/util/FlowEntryId.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/util/FlowEntryId.java
@@ -5,6 +5,7 @@
 import net.onrc.onos.ofcontroller.util.serializers.FlowEntryIdDeserializer;
 import net.onrc.onos.ofcontroller.util.serializers.FlowEntryIdSerializer;
 
+import org.codehaus.jackson.annotate.JsonIgnore;
 import org.codehaus.jackson.map.annotate.JsonDeserialize;
 import org.codehaus.jackson.map.annotate.JsonSerialize;
 
@@ -20,7 +21,7 @@
      * Default constructor.
      */
     public FlowEntryId() {
-	this.value = 0;
+	this.value = -1;
     }
 
     /**
@@ -66,7 +67,17 @@
     public void setValue(long value) {
 	this.value = value;
     }
-    
+
+    /**
+     * Test whether the Flow Entry ID is valid.
+     *
+     * @return true if the Flow Entry ID is valid, otherwise false.
+     */
+    @JsonIgnore
+    public boolean isValid() {
+	return (this.value() != -1);
+    }
+
     /**
      * Returns true of the object is another Flow Entry ID with 
      * the same value; otherwise, returns false.
diff --git a/src/main/java/net/onrc/onos/ofcontroller/util/FlowId.java b/src/main/java/net/onrc/onos/ofcontroller/util/FlowId.java
index de955ba..d90e96f 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/util/FlowId.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/util/FlowId.java
@@ -5,6 +5,7 @@
 import net.onrc.onos.ofcontroller.util.serializers.FlowIdDeserializer;
 import net.onrc.onos.ofcontroller.util.serializers.FlowIdSerializer;
 
+import org.codehaus.jackson.annotate.JsonIgnore;
 import org.codehaus.jackson.map.annotate.JsonDeserialize;
 import org.codehaus.jackson.map.annotate.JsonSerialize;
 
@@ -20,7 +21,7 @@
      * Default constructor.
      */
     public FlowId() {
-	this.value = 0;
+	this.value = -1;
     }
 
     /**
@@ -68,6 +69,16 @@
     }
 
     /**
+     * Test whether the Flow ID is valid.
+     *
+     * @return true if the Flow ID is valid, otherwise false.
+     */
+    @JsonIgnore
+    public boolean isValid() {
+	return (this.value() != -1);
+    }
+
+    /**
      * Convert the Flow ID value to a hexadecimal string.
      *
      * @return the Flow ID value to a hexadecimal string.
diff --git a/src/test/java/net/onrc/onos/ofcontroller/flowmanager/FlowManagerTest.java b/src/test/java/net/onrc/onos/ofcontroller/flowmanager/FlowManagerTest.java
index 7fd0f67..8a727d3 100644
--- a/src/test/java/net/onrc/onos/ofcontroller/flowmanager/FlowManagerTest.java
+++ b/src/test/java/net/onrc/onos/ofcontroller/flowmanager/FlowManagerTest.java
@@ -239,49 +239,48 @@
 		verifyAll();
 		assertTrue(result);
 	}
-	
+
 	/**
-	 * Test method for {@link FlowManager#deleteAllFlows()}.
-	 * @throws Exception 
+	 * Test method for {@link FlowManager#deleteFlow(FlowId)}.
+	 * @throws Exception
 	 */
 	@Test
-	public final void testDeleteAllFlowsSuccessNormally() throws Exception {
+	public final void testDeleteFlowSuccessNormally() throws Exception {
 		// create mock objects
-		IFlowPath flowPath1 = createNiceMock(IFlowPath.class);
-		IFlowPath flowPath2 = createNiceMock(IFlowPath.class);
+		IFlowPath flowPath = createIFlowPathMock(123, "id", "FP_TYPE_SHORTEST_PATH", "FP_USER_ADD", 0, 1, 2, 3, 4);
+		IFlowEntry flowEntry1 = createMock(IFlowEntry.class);
+		IFlowEntry flowEntry2 = createMock(IFlowEntry.class);
+		IFlowEntry flowEntry3 = createMock(IFlowEntry.class);
 		
 		// instantiate required objects
-		ArrayList<IFlowPath> flowPaths = new ArrayList<IFlowPath>();
-		flowPaths.add(flowPath1);
-		flowPaths.add(flowPath2);
 		FlowManager fm = new FlowManager();
-		
+		FlowId flowId = new FlowId(123);
+		ArrayList<IFlowEntry> flowEntries = new ArrayList<IFlowEntry>();
+		flowEntries.add(flowEntry1);
+		flowEntries.add(flowEntry2);
+		flowEntries.add(flowEntry3);
+
 		// setup expectations
 		expectInitWithContext();
-		expect(op.getAllFlowPaths()).andReturn(flowPaths);
-
-		expect(flowPath1.getFlowId()).andReturn("1").anyTimes();
-		expect(op.searchFlowPath(cmpEq(new FlowId(1)))).andReturn(flowPath1);
-		expect(flowPath1.getFlowEntries()).andReturn(new ArrayList<IFlowEntry>());
-		op.removeFlowPath(flowPath1);
-		
-		expect(flowPath2.getFlowId()).andReturn("2").anyTimes();
-		expect(op.searchFlowPath(cmpEq(new FlowId(2)))).andReturn(flowPath2);
-		expect(flowPath2.getFlowEntries()).andReturn(new ArrayList<IFlowEntry>());
-		op.removeFlowPath(flowPath2);
-
+		expect(op.searchFlowPath(cmpEq(flowId))).andReturn(flowPath);
+		expect(flowPath.getFlowEntries()).andReturn(flowEntries);
+		flowPath.removeFlowEntry(flowEntry1);
+		flowPath.removeFlowEntry(flowEntry2);
+		flowPath.removeFlowEntry(flowEntry3);
+		op.removeFlowEntry(flowEntry1);
+		op.removeFlowEntry(flowEntry2);
+		op.removeFlowEntry(flowEntry3);
+		op.removeFlowPath(flowPath);
 		op.commit();
-		expectLastCall().anyTimes();
 
 		// start the test
 		replayAll();
 		
 		fm.init(context);
-		Boolean result = fm.deleteAllFlows();
+		fm.deleteFlow(flowId);
 
 		// verify the test
 		verifyAll();
-		assertTrue(result);
 	}
 	
 	/**
@@ -316,16 +315,16 @@
 	}
 	
 	/**
-	 * Test method for {@link FlowManager#clearAllFlows()}.
+	 * Test method for {@link FlowManager#deleteAllFlows()}.
 	 * @throws Exception 
 	 */
 	@Test
-	public final void testClearAllFlowsSuccessNormally() throws Exception {
+	public final void testDeleteAllFlowsSuccessNormally() throws Exception {
 		// create mock objects
 		IFlowPath flowPath1 = createNiceMock(IFlowPath.class);
 		IFlowPath flowPath2 = createNiceMock(IFlowPath.class);
 		IFlowPath flowPath3 = createNiceMock(IFlowPath.class);
-		FlowManager fm = createPartialMockAndInvokeDefaultConstructor(FlowManager.class, "clearFlow");
+		FlowManager fm = createPartialMockAndInvokeDefaultConstructor(FlowManager.class, "deleteFlow");
 		
 		// instantiate required objects
 		ArrayList<IFlowPath> flowPaths = new ArrayList<IFlowPath>();
@@ -340,16 +339,16 @@
 		expect(flowPath1.getFlowId()).andReturn(new FlowId(1).toString());
 		expect(flowPath2.getFlowId()).andReturn(null);
 		expect(flowPath3.getFlowId()).andReturn(new FlowId(3).toString());
-		expect(fm.clearFlow(cmpEq(new FlowId(1)))).andReturn(true);
-		expect(fm.clearFlow(cmpEq(new FlowId(3)))).andReturn(true);
+		expect(fm.deleteFlow(cmpEq(new FlowId(1)))).andReturn(true);
+		expect(fm.deleteFlow(cmpEq(new FlowId(3)))).andReturn(true);
 		
 		// start the test
 		replayAll();
 
 		fm.init(context);
-		Boolean result = fm.clearAllFlows();
+		Boolean result = fm.deleteAllFlows();
 		
-		//verify the test
+		// verify the test
 		verifyAll();
 		assertTrue(result);
 	}
@@ -464,35 +463,35 @@
 	 */
 	@Test
 	public final void testGetAllFlowsSummarySuccessNormally() throws Exception {
-		final String getAllFlowsWithoutFlowEntries = "getAllFlowsWithoutFlowEntries";
+		final String getAllFlowsWithDataPathSummary = "getAllFlowsWithDataPathSummary";
 		// create mock objects
-		FlowManager fm = createPartialMockAndInvokeDefaultConstructor(FlowManager.class, getAllFlowsWithoutFlowEntries);
-		IFlowPath flowPath1 = createIFlowPathMock(1, "", "FP_TYPE_SHORTEST_PATH", "FP_USER_ADD", 0, 1, 2, 3, 4);
-		IFlowPath flowPath2 = createIFlowPathMock(5, "", "FP_TYPE_SHORTEST_PATH", "FP_USER_ADD", 0, 2, 3, 4, 5);
-		IFlowPath flowPath3 = createIFlowPathMock(10, "", "FP_TYPE_SHORTEST_PATH", "FP_USER_ADD", 0, 3, 4, 5, 6);
+		FlowManager fm = createPartialMockAndInvokeDefaultConstructor(FlowManager.class, getAllFlowsWithDataPathSummary);
+		FlowPath flowPath1 = createTestFlowPath(1, "", "FP_TYPE_SHORTEST_PATH", "FP_USER_ADD", 0, 1, 2, 3, 4);
+		FlowPath flowPath2 = createTestFlowPath(5, "", "FP_TYPE_SHORTEST_PATH", "FP_USER_ADD", 0, 2, 3, 4, 5);
+		FlowPath flowPath3 = createTestFlowPath(10, "", "FP_TYPE_SHORTEST_PATH", "FP_USER_ADD", 0, 3, 4, 5, 6);
 
 		// instantiate required objects
-		ArrayList<IFlowPath> flows = new ArrayList<IFlowPath>();
+		ArrayList<FlowPath> flows = new ArrayList<FlowPath>();
 		flows.add(flowPath3);
 		flows.add(flowPath1);
 		flows.add(flowPath2);
 		
 		// setup expectations
 		expectInitWithContext();
-		expectPrivate(fm, getAllFlowsWithoutFlowEntries).andReturn(flows);
+		expectPrivate(fm, getAllFlowsWithDataPathSummary).andReturn(flows);
 
 		// start the test
 		replayAll();
 		
 		fm.init(context);
-		ArrayList<IFlowPath> returnedFlows = fm.getAllFlowsSummary(null, 0);
+		ArrayList<FlowPath> returnedFlows = fm.getAllFlowsSummary(null, 0);
 		
 		// verify the test
 		verifyAll();
 		assertEquals(3, returnedFlows.size());
-		assertEquals(1, new FlowId(returnedFlows.get(0).getFlowId()).value());
-		assertEquals(5, new FlowId(returnedFlows.get(1).getFlowId()).value());
-		assertEquals(10, new FlowId(returnedFlows.get(2).getFlowId()).value());
+		assertEquals(1, new FlowId(returnedFlows.get(0).flowId().value()).value());
+		assertEquals(5, new FlowId(returnedFlows.get(1).flowId().value()).value());
+		assertEquals(10, new FlowId(returnedFlows.get(2).flowId().value()).value());
 	}
 
 	/**
@@ -786,85 +785,6 @@
 	
 	// other methods
 	
-	
-	/**
-	 * Test method for {@link FlowManager#clearFlow(FlowId)}.
-	 * @throws Exception
-	 */
-	@Test
-	public final void testClearFlowSuccessNormally() throws Exception {
-		// create mock objects
-		IFlowPath flowPath = createIFlowPathMock(123, "id", "FP_TYPE_SHORTEST_PATH", "FP_USER_ADD", 0, 1, 2, 3, 4);
-		IFlowEntry flowEntry1 = createMock(IFlowEntry.class);
-		IFlowEntry flowEntry2 = createMock(IFlowEntry.class);
-		IFlowEntry flowEntry3 = createMock(IFlowEntry.class);
-		
-		// instantiate required objects
-		FlowManager fm = new FlowManager();
-		FlowId flowId = new FlowId(123);
-		ArrayList<IFlowEntry> flowEntries = new ArrayList<IFlowEntry>();
-		flowEntries.add(flowEntry1);
-		flowEntries.add(flowEntry2);
-		flowEntries.add(flowEntry3);
-
-		// setup expectations
-		expectInitWithContext();
-		expect(op.searchFlowPath(cmpEq(flowId))).andReturn(flowPath);
-		expect(flowPath.getFlowEntries()).andReturn(flowEntries);
-		flowPath.removeFlowEntry(flowEntry1);
-		flowPath.removeFlowEntry(flowEntry2);
-		flowPath.removeFlowEntry(flowEntry3);
-		op.removeFlowEntry(flowEntry1);
-		op.removeFlowEntry(flowEntry2);
-		op.removeFlowEntry(flowEntry3);
-		op.removeFlowPath(flowPath);
-		op.commit();
-
-		// start the test
-		replayAll();
-		
-		fm.init(context);
-		fm.clearFlow(flowId);
-
-		// verify the test
-		verifyAll();
-	}
-	
-	/**
-	 * Test method for {@link FlowManager#getAllFlowsWithoutFlowEntries()}.
-	 * @throws Exception 
-	 */
-	@Test
-	public final void testGetAllFlowsWithoutFlowEntriesSuccessNormally() throws Exception {
-		// create mock objects
-		IFlowPath iFlowPath1 = createIFlowPathMock(1, "caller id", "FP_TYPE_SHORTEST_PATH", "FP_USER_ADD", 0, 1, 1, 2, 2); 
-		IFlowPath iFlowPath2 = createIFlowPathMock(2, "caller id", "FP_TYPE_SHORTEST_PATH", "FP_USER_ADD", 0, 2, 5, 3, 5);
-		
-		// instantiate required objects
-		ArrayList<IFlowPath> flowPaths = new ArrayList<IFlowPath>();
-		flowPaths.add(iFlowPath1);
-		flowPaths.add(iFlowPath2);
-		FlowManager fm = new FlowManager();
-		
-		// setup expectations
-		expectInitWithContext();
-		op.commit();
-		expect(op.getAllFlowPaths()).andReturn(flowPaths);
-		
-		// start the test
-		replayAll();
-		
-		fm.init(context);
-		ArrayList<IFlowPath> result = fm.getAllFlowsWithoutFlowEntries();
-		
-		// verify the test
-		verifyAll();
-		assertEquals(iFlowPath1, result.get(0));
-		assertEquals(iFlowPath2, result.get(1));
-		
-		// TODO: does this method just return the replica of the flow paths?
-	}
-	
 	/**
 	 * Test method for {@link FlowManager#reconcileFlow(IFlowPath, DataPath)}.
 	 * @throws Exception
diff --git a/src/test/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowPusherTest.java b/src/test/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowPusherTest.java
new file mode 100644
index 0000000..4c66367
--- /dev/null
+++ b/src/test/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowPusherTest.java
@@ -0,0 +1,562 @@
+package net.onrc.onos.ofcontroller.flowprogrammer;
+
+import static org.junit.Assert.*;
+import static org.powermock.api.easymock.PowerMock.createMock;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+
+import net.floodlightcontroller.core.FloodlightContext;
+import net.floodlightcontroller.core.IFloodlightProviderService;
+import net.floodlightcontroller.core.IOFSwitch;
+import net.floodlightcontroller.core.module.FloodlightModuleContext;
+import net.floodlightcontroller.threadpool.IThreadPoolService;
+import net.floodlightcontroller.util.OFMessageDamper;
+import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IFlowEntry;
+import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IFlowPath;
+import net.onrc.onos.ofcontroller.util.CallerId;
+import net.onrc.onos.ofcontroller.util.DataPath;
+import net.onrc.onos.ofcontroller.util.Dpid;
+import net.onrc.onos.ofcontroller.util.FlowEntry;
+import net.onrc.onos.ofcontroller.util.FlowEntryAction;
+import net.onrc.onos.ofcontroller.util.FlowEntryActions;
+import net.onrc.onos.ofcontroller.util.FlowEntryErrorState;
+import net.onrc.onos.ofcontroller.util.FlowEntryId;
+import net.onrc.onos.ofcontroller.util.FlowEntryMatch;
+import net.onrc.onos.ofcontroller.util.FlowEntryUserState;
+import net.onrc.onos.ofcontroller.util.FlowId;
+import net.onrc.onos.ofcontroller.util.FlowPath;
+import net.onrc.onos.ofcontroller.util.FlowPathFlags;
+import net.onrc.onos.ofcontroller.util.FlowPathType;
+import net.onrc.onos.ofcontroller.util.FlowPathUserState;
+import net.onrc.onos.ofcontroller.util.Port;
+import net.onrc.onos.ofcontroller.util.SwitchPort;
+
+import org.easymock.EasyMock;
+import org.easymock.IAnswer;
+import org.junit.Ignore;
+import org.junit.Test;
+import org.openflow.protocol.OFBarrierRequest;
+import org.openflow.protocol.OFFlowMod;
+import org.openflow.protocol.OFMatch;
+import org.openflow.protocol.OFMessage;
+import org.openflow.protocol.OFType;
+import org.openflow.protocol.action.OFAction;
+import org.openflow.protocol.factory.BasicFactory;
+
+public class FlowPusherTest {
+	private FlowPusher pusher;
+	private FloodlightContext context;
+	private FloodlightModuleContext modContext;
+	private BasicFactory factory;
+	private OFMessageDamper damper;
+	private IFloodlightProviderService flservice;
+	private IThreadPoolService tpservice;
+
+	/**
+	 * Test single OFMessage is correctly sent to single switch via MessageDamper.
+	 */
+	@Test
+	public void testAddMessage() {
+		beginInitMock();
+		
+		OFMessage msg = EasyMock.createMock(OFMessage.class);
+		EasyMock.expect(msg.getXid()).andReturn(1).anyTimes();
+		EasyMock.expect(msg.getLength()).andReturn((short)100).anyTimes();
+		EasyMock.replay(msg);
+		
+		IOFSwitch sw = EasyMock.createMock(IOFSwitch.class);
+		EasyMock.expect(sw.getId()).andReturn((long)1).anyTimes();
+		sw.flush();
+		EasyMock.expectLastCall().once();
+		EasyMock.replay(sw);
+		
+		try {
+			EasyMock.expect(damper.write(EasyMock.eq(sw), EasyMock.eq(msg), EasyMock.eq(context))).andReturn(true).once();
+		} catch (IOException e1) {
+			fail("Failed in OFMessageDamper#write()");
+		}
+		
+		endInitMock();
+		initPusher(1);
+		
+		boolean add_result = pusher.add(sw, msg);
+		assertTrue(add_result);
+		
+		try {
+			// wait until message is processed.
+			Thread.sleep(1000);
+		} catch (InterruptedException e) {
+			fail("Failed in Thread.sleep()");
+		}
+		
+		EasyMock.verify(msg);
+		EasyMock.verify(sw);
+		
+		pusher.stop();
+	}
+	
+	/**
+	 * Test bunch of OFMessages are correctly sent to single switch via MessageDamper.
+	 */
+	@Test
+	public void testMassiveAddMessage() {
+		final int NUM_MSG = 10000;
+		
+		beginInitMock();
+
+		IOFSwitch sw = EasyMock.createMock(IOFSwitch.class);
+		EasyMock.expect(sw.getId()).andReturn((long)1).anyTimes();
+		sw.flush();
+		EasyMock.expectLastCall().atLeastOnce();
+		EasyMock.replay(sw);
+		
+		List<OFMessage> messages = new ArrayList<OFMessage>();
+		
+		for (int i = 0; i < NUM_MSG; ++i) {
+			OFMessage msg = EasyMock.createMock(OFMessage.class);
+			EasyMock.expect(msg.getXid()).andReturn(i).anyTimes();
+			EasyMock.expect(msg.getLength()).andReturn((short)100).anyTimes();
+			EasyMock.replay(msg);
+			messages.add(msg);
+			
+			try {
+				EasyMock.expect(damper.write(EasyMock.eq(sw), EasyMock.eq(msg), EasyMock.eq(context)))
+					.andReturn(true).once();
+			} catch (IOException e1) {
+				fail("Failed in OFMessageDamper#write()");
+			}
+		}
+		
+		endInitMock();
+		initPusher(1);
+		
+		for (OFMessage msg : messages) {
+			boolean add_result = pusher.add(sw, msg);
+			assertTrue(add_result);
+		}
+		
+		try {
+			// wait until message is processed.
+			Thread.sleep(1000);
+		} catch (InterruptedException e) {
+			fail("Failed in Thread.sleep()");
+		}
+		
+		for (OFMessage msg : messages) {
+			EasyMock.verify(msg);
+		}
+		EasyMock.verify(sw);
+		
+		pusher.stop();
+	}
+	
+	/**
+	 * Test bunch of OFMessages are correctly sent to multiple switches with single threads.
+	 */
+	@Test
+	public void testMultiSwitchAddMessage() {
+		final int NUM_SWITCH = 10;
+		final int NUM_MSG = 100;	// messages per thread
+		
+		beginInitMock();
+
+		Map<IOFSwitch, List<OFMessage>> sw_map = new HashMap<IOFSwitch, List<OFMessage>>();
+		for (int i = 0; i < NUM_SWITCH; ++i) {
+			IOFSwitch sw = EasyMock.createMock(IOFSwitch.class);
+			EasyMock.expect(sw.getId()).andReturn((long)i).anyTimes();
+			sw.flush();
+			EasyMock.expectLastCall().atLeastOnce();
+			EasyMock.replay(sw);
+			
+			List<OFMessage> messages = new ArrayList<OFMessage>();
+			
+			for (int j = 0; j < NUM_MSG; ++j) {
+				OFMessage msg = EasyMock.createMock(OFMessage.class);
+				EasyMock.expect(msg.getXid()).andReturn(j).anyTimes();
+				EasyMock.expect(msg.getLength()).andReturn((short)100).anyTimes();
+				EasyMock.replay(msg);
+				messages.add(msg);
+				
+				try {
+					EasyMock.expect(damper.write(EasyMock.eq(sw), EasyMock.eq(msg), EasyMock.eq(context)))
+						.andReturn(true).once();
+				} catch (IOException e1) {
+					fail("Failed in OFMessageDamper#write()");
+				}
+			}
+			sw_map.put(sw, messages);
+		}
+		
+		endInitMock();
+		initPusher(1);
+		
+		for (IOFSwitch sw : sw_map.keySet()) {
+			for (OFMessage msg : sw_map.get(sw)) {
+				boolean add_result = pusher.add(sw, msg);
+				assertTrue(add_result);
+			}
+		}
+		
+		try {
+			// wait until message is processed.
+			Thread.sleep(1000);
+		} catch (InterruptedException e) {
+			fail("Failed in Thread.sleep()");
+		}
+		
+		for (IOFSwitch sw : sw_map.keySet()) {
+			for (OFMessage msg : sw_map.get(sw)) {
+				EasyMock.verify(msg);
+			}
+			
+			EasyMock.verify(sw);
+		}
+		
+		pusher.stop();
+	}
+	
+	/**
+	 * Test bunch of OFMessages are correctly sent to multiple switches using multiple threads.
+	 */
+	@Test
+	public void testMultiThreadedAddMessage() {
+		final int NUM_THREAD = 10;
+		final int NUM_MSG = 100;	// messages per thread
+		
+		beginInitMock();
+
+		Map<IOFSwitch, List<OFMessage>> sw_map = new HashMap<IOFSwitch, List<OFMessage>>();
+		for (int i = 0; i < NUM_THREAD; ++i) {
+			IOFSwitch sw = EasyMock.createMock(IOFSwitch.class);
+			EasyMock.expect(sw.getId()).andReturn((long)i).anyTimes();
+			sw.flush();
+			EasyMock.expectLastCall().atLeastOnce();
+			EasyMock.replay(sw);
+			
+			List<OFMessage> messages = new ArrayList<OFMessage>();
+			
+			for (int j = 0; j < NUM_MSG; ++j) {
+				OFMessage msg = EasyMock.createMock(OFMessage.class);
+				EasyMock.expect(msg.getXid()).andReturn(j).anyTimes();
+				EasyMock.expect(msg.getLength()).andReturn((short)100).anyTimes();
+				EasyMock.replay(msg);
+				messages.add(msg);
+				
+				try {
+					EasyMock.expect(damper.write(EasyMock.eq(sw), EasyMock.eq(msg), EasyMock.eq(context)))
+						.andReturn(true).once();
+				} catch (IOException e1) {
+					fail("Failed in OFMessageDamper#write()");
+				}
+			}
+			sw_map.put(sw, messages);
+		}
+		
+		endInitMock();
+		initPusher(NUM_THREAD);
+		
+		for (IOFSwitch sw : sw_map.keySet()) {
+			for (OFMessage msg : sw_map.get(sw)) {
+				boolean add_result = pusher.add(sw, msg);
+				assertTrue(add_result);
+			}
+		}
+		
+		try {
+			// wait until message is processed.
+			Thread.sleep(1000);
+		} catch (InterruptedException e) {
+			fail("Failed in Thread.sleep()");
+		}
+		
+		for (IOFSwitch sw : sw_map.keySet()) {
+			for (OFMessage msg : sw_map.get(sw)) {
+				EasyMock.verify(msg);
+			}
+			
+			EasyMock.verify(sw);
+		}
+		
+		pusher.stop();
+	}
+	
+	private long barrierTime = 0;
+	/**
+	 * Test rate limitation of messages works correctly.
+	 */
+	@Test
+	public void testRateLimitedAddMessage() {
+		final long LIMIT_RATE = 100; // [bytes/ms]
+		final int NUM_MSG = 1000;
+		
+		// Accuracy of FlowPusher's rate calculation can't be measured by unit test
+		// because switch doesn't return BARRIER_REPLY.
+		// In unit test we use approximate way to measure rate. This value is 
+		// acceptable margin of measured rate.
+		final double ACCEPTABLE_RATE = LIMIT_RATE * 1.2;
+		
+		beginInitMock();
+
+		IOFSwitch sw = EasyMock.createMock(IOFSwitch.class);
+		EasyMock.expect(sw.getId()).andReturn((long)1).anyTimes();
+		sw.flush();
+		EasyMock.expectLastCall().atLeastOnce();
+		prepareBarrier(sw);
+		EasyMock.replay(sw);
+		
+		List<OFMessage> messages = new ArrayList<OFMessage>();
+		
+		for (int i = 0; i < NUM_MSG; ++i) {
+			OFMessage msg = EasyMock.createMock(OFMessage.class);
+			EasyMock.expect(msg.getXid()).andReturn(1).anyTimes();
+			EasyMock.expect(msg.getLength()).andReturn((short)100).anyTimes();
+			EasyMock.expect(msg.getLengthU()).andReturn(100).anyTimes();
+			EasyMock.replay(msg);
+			messages.add(msg);
+			
+			try {
+				EasyMock.expect(damper.write(EasyMock.eq(sw), EasyMock.eq(msg), EasyMock.eq(context)))
+					.andReturn(true).once();
+			} catch (IOException e) {
+				fail("Failed in OFMessageDamper#write()");
+			}
+		}
+		
+		try {
+			EasyMock.expect(damper.write(EasyMock.eq(sw), (OFMessage)EasyMock.anyObject(), EasyMock.eq(context)))
+				.andAnswer(new IAnswer<Boolean>() {
+					@Override
+					public Boolean answer() throws Throwable {
+						OFMessage msg = (OFMessage)EasyMock.getCurrentArguments()[1];
+						if (msg.getType() == OFType.BARRIER_REQUEST) {
+							barrierTime = System.currentTimeMillis();
+						}
+						return true;
+					}
+				}).once();
+		} catch (IOException e1) {
+			fail("Failed in OFMessageDamper#write()");
+		}
+
+		endInitMock();
+		initPusher(1);
+		
+		pusher.createQueue(sw);
+		pusher.setRate(sw, LIMIT_RATE);
+		
+		long beginTime = System.currentTimeMillis();
+		for (OFMessage msg : messages) {
+			boolean add_result = pusher.add(sw, msg);
+			assertTrue(add_result);
+		}
+		
+		pusher.barrierAsync(sw);
+
+		try {
+			do {
+				Thread.sleep(1000);
+			} while (barrierTime == 0);
+		} catch (InterruptedException e) {
+			fail("Failed to sleep");
+		}
+		
+		double measured_rate = NUM_MSG * 100 /  (barrierTime - beginTime);
+		assertTrue(measured_rate < ACCEPTABLE_RATE);
+		
+		for (OFMessage msg : messages) {
+			EasyMock.verify(msg);
+		}
+		EasyMock.verify(sw);
+		
+		pusher.stop();
+	}
+
+	/**
+	 * Test barrier message is correctly sent to a switch.
+	 */
+	@Test
+	public void testBarrierMessage() {
+		beginInitMock();
+		
+		IOFSwitch sw = EasyMock.createMock(IOFSwitch.class);
+		EasyMock.expect(sw.getId()).andReturn((long)1).anyTimes();
+		sw.flush();
+		EasyMock.expectLastCall().atLeastOnce();
+		prepareBarrier(sw);
+		EasyMock.replay(sw);
+
+		try {
+			EasyMock.expect(damper.write(EasyMock.eq(sw), (OFMessage)EasyMock.anyObject(), EasyMock.eq(context)))
+				.andReturn(true).once();
+		} catch (IOException e1) {
+			fail("Failed in OFMessageDamper#write()");
+		}
+
+		endInitMock();
+		initPusher(1);
+
+		OFBarrierReplyFuture future = pusher.barrierAsync(sw);
+		
+		assertNotNull(future);
+		pusher.stop();
+	}
+	
+	/**
+	 * Test FlowObject is correctly converted to message and is sent to a switch.
+	 */
+	@SuppressWarnings("unchecked")
+	@Test
+	public void testAddFlow() {
+		// Code below are copied from FlowManagerTest
+		
+		// instantiate required objects
+		FlowEntry flowEntry1 = new FlowEntry();
+		flowEntry1.setDpid(new Dpid(1));
+		flowEntry1.setFlowId(new FlowId(1));
+		flowEntry1.setInPort(new Port((short) 1));
+		flowEntry1.setOutPort(new Port((short) 11));
+		flowEntry1.setFlowEntryId(new FlowEntryId(1));
+		flowEntry1.setFlowEntryMatch(new FlowEntryMatch());
+		flowEntry1.setFlowEntryActions(new FlowEntryActions());
+		flowEntry1.setFlowEntryErrorState(new FlowEntryErrorState());
+		flowEntry1.setFlowEntryUserState(FlowEntryUserState.FE_USER_ADD);
+		
+		beginInitMock();
+		
+		OFFlowMod msg = EasyMock.createMock(OFFlowMod.class);
+		EasyMock.expect(msg.setIdleTimeout(EasyMock.anyShort())).andReturn(msg);
+		EasyMock.expect(msg.setHardTimeout(EasyMock.anyShort())).andReturn(msg);
+		EasyMock.expect(msg.setPriority(EasyMock.anyShort())).andReturn(msg);
+		EasyMock.expect(msg.setBufferId(EasyMock.anyInt())).andReturn(msg);
+		EasyMock.expect(msg.setCookie(EasyMock.anyLong())).andReturn(msg);
+		EasyMock.expect(msg.setCommand(EasyMock.anyShort())).andReturn(msg);
+		EasyMock.expect(msg.setMatch(EasyMock.anyObject(OFMatch.class))).andReturn(msg);
+		EasyMock.expect(msg.setActions((List<OFAction>)EasyMock.anyObject())).andReturn(msg);
+		EasyMock.expect(msg.setLengthU(EasyMock.anyShort())).andReturn(msg);
+		EasyMock.expect(msg.setOutPort(EasyMock.anyShort())).andReturn(msg).atLeastOnce();
+		EasyMock.expect(msg.getXid()).andReturn(1).anyTimes();
+		EasyMock.expect(msg.getType()).andReturn(OFType.FLOW_MOD).anyTimes();
+		EasyMock.expect(msg.getLength()).andReturn((short)100).anyTimes();
+		EasyMock.replay(msg);
+		
+		EasyMock.expect(factory.getMessage(EasyMock.eq(OFType.FLOW_MOD))).andReturn(msg);
+		
+		ScheduledExecutorService executor = EasyMock.createMock(ScheduledExecutorService.class);
+		EasyMock.expect(executor.schedule((Runnable)EasyMock.anyObject(), EasyMock.anyLong(),
+				(TimeUnit)EasyMock.anyObject())).andReturn(null).once();
+		EasyMock.replay(executor);
+		EasyMock.expect(tpservice.getScheduledExecutor()).andReturn(executor);
+
+		IOFSwitch sw = EasyMock.createMock(IOFSwitch.class);
+		EasyMock.expect(sw.getId()).andReturn((long)1).anyTimes();
+		EasyMock.expect(sw.getStringId()).andReturn("1").anyTimes();
+		sw.flush();
+		EasyMock.expectLastCall().once();
+		EasyMock.replay(sw);
+		
+		try {
+			EasyMock.expect(damper.write(EasyMock.eq(sw), EasyMock.anyObject(OFMessage.class), EasyMock.eq(context)))
+				.andAnswer(new IAnswer<Boolean>() {
+					@Override
+					public Boolean answer() throws Throwable {
+						OFMessage msg = (OFMessage)EasyMock.getCurrentArguments()[1];
+						assertEquals(msg.getType(), OFType.FLOW_MOD);
+						return true;
+					}
+				}).once();
+		} catch (IOException e1) {
+			fail("Failed in OFMessageDamper#write()");
+		}
+		
+		endInitMock();
+		initPusher(1);
+
+		pusher.add(sw, flowEntry1);
+		
+		try {
+			Thread.sleep(1000);
+		} catch (InterruptedException e) {
+			fail("Failed to sleep");
+		}
+		
+		EasyMock.verify(sw);
+		
+		pusher.stop();
+	}
+	
+	private void beginInitMock() {
+		context = EasyMock.createMock(FloodlightContext.class);
+		modContext = EasyMock.createMock(FloodlightModuleContext.class);
+		factory = EasyMock.createMock(BasicFactory.class);
+		damper = EasyMock.createMock(OFMessageDamper.class);
+		flservice = EasyMock.createMock(IFloodlightProviderService.class);
+		tpservice = EasyMock.createMock(IThreadPoolService.class);
+		
+		EasyMock.expect(modContext.getServiceImpl(EasyMock.eq(IThreadPoolService.class)))
+			.andReturn(tpservice).once();
+		EasyMock.expect(modContext.getServiceImpl(EasyMock.eq(IFloodlightProviderService.class)))
+			.andReturn(flservice).once();
+		flservice.addOFMessageListener(EasyMock.eq(OFType.BARRIER_REPLY),
+				(FlowPusher) EasyMock.anyObject());
+		EasyMock.expectLastCall().once();
+	}
+	
+	private void endInitMock() {
+		EasyMock.replay(tpservice);
+		EasyMock.replay(flservice);
+		EasyMock.replay(damper);
+		EasyMock.replay(factory);
+		EasyMock.replay(modContext);
+		EasyMock.replay(context);
+	}
+	
+	private void initPusher(int num_thread) {
+		pusher = new FlowPusher(num_thread);
+		pusher.init(context, modContext, factory, damper);
+		pusher.start();
+	}
+	
+	private void prepareBarrier(IOFSwitch sw) {
+		OFBarrierRequest req = EasyMock.createMock(OFBarrierRequest.class);
+		req.setXid(EasyMock.anyInt());
+		EasyMock.expectLastCall().once();
+		EasyMock.expect(req.getXid()).andReturn(1).anyTimes();
+		EasyMock.expect(req.getType()).andReturn(OFType.BARRIER_REQUEST).anyTimes();
+		EasyMock.expect(req.getLength()).andReturn((short)100).anyTimes();
+		EasyMock.replay(req);
+		EasyMock.expect(factory.getMessage(EasyMock.eq(OFType.BARRIER_REQUEST))).andReturn(req);
+		
+		ScheduledExecutorService executor = EasyMock.createMock(ScheduledExecutorService.class);
+		EasyMock.expect(executor.schedule((Runnable)EasyMock.anyObject(), EasyMock.anyLong(),
+				(TimeUnit)EasyMock.anyObject())).andReturn(null).once();
+		EasyMock.replay(executor);
+		EasyMock.expect(tpservice.getScheduledExecutor()).andReturn(executor);
+
+		EasyMock.expect(sw.getNextTransactionId()).andReturn(1);
+	}
+	
+	// Copied from FlowManagerTest
+	private IFlowPath createIFlowPathMock(long flowId, String installerID,
+			String flowPathType, String flowPathUserState,
+			long flowPathFlags, long srcDpid, int srcPort,
+			long dstDpid, int dstPort) {
+		IFlowPath iFlowPath = EasyMock.createNiceMock(IFlowPath.class);
+		EasyMock.expect(iFlowPath.getFlowId()).andReturn(new FlowId(flowId).toString()).anyTimes();
+		EasyMock.expect(iFlowPath.getInstallerId()).andReturn(installerID).anyTimes();
+		EasyMock.expect(iFlowPath.getFlowPathType()).andReturn(flowPathType).anyTimes();
+		EasyMock.expect(iFlowPath.getFlowPathUserState()).andReturn(flowPathUserState).anyTimes();
+		EasyMock.expect(iFlowPath.getFlowPathFlags()).andReturn(new Long(flowPathFlags)).anyTimes();
+		EasyMock.expect(iFlowPath.getSrcSwitch()).andReturn(new Dpid(srcDpid).toString()).anyTimes();
+		EasyMock.expect(iFlowPath.getSrcPort()).andReturn(new Short((short)srcPort)).anyTimes();
+		EasyMock.expect(iFlowPath.getDstSwitch()).andReturn(new Dpid(dstDpid).toString()).anyTimes();
+		EasyMock.expect(iFlowPath.getDstPort()).andReturn(new Short((short)dstPort)).anyTimes();
+		return iFlowPath;
+	}
+	
+}
diff --git a/web/clear_flow.py b/web/clear_flow.py
deleted file mode 100755
index db70d40..0000000
--- a/web/clear_flow.py
+++ /dev/null
@@ -1,81 +0,0 @@
-#! /usr/bin/env python
-# -*- Mode: python; py-indent-offset: 4; tab-width: 8; indent-tabs-mode: t; -*-
-
-import pprint
-import os
-import sys
-import subprocess
-import json
-import argparse
-import io
-import time
-
-from flask import Flask, json, Response, render_template, make_response, request
-
-#
-# TODO: remove this! We don't use JSON argument here!
-# curl http://127.0.0.1:8080/wm/flow/clear/{"value":"0xf"}/json'
-#
-
-## Global Var ##
-ControllerIP="127.0.0.1"
-ControllerPort=8080
-
-DEBUG=0
-pp = pprint.PrettyPrinter(indent=4)
-
-app = Flask(__name__)
-
-## Worker Functions ##
-def log_error(txt):
-  print '%s' % (txt)
-
-def debug(txt):
-  if DEBUG:
-    print '%s' % (txt)
-
-# @app.route("/wm/flow/clear/<flow-id>/json")
-def clear_flow_path(flow_id):
-  command = "curl -s \"http://%s:%s/wm/flow/clear/%s/json\"" % (ControllerIP, ControllerPort, flow_id)
-  debug("clear_flow_path %s" % command)
-  result = os.popen(command).read()
-  debug("result %s" % result)
-  # parsedResult = json.loads(result)
-  # debug("parsed %s" % parsedResult)
-
-if __name__ == "__main__":
-  usage_msg = "Clear flow state from the ONOS Network Map\n"
-  usage_msg = usage_msg + "Usage: %s <begin-flow-id> <end-flow-id>\n" % (sys.argv[0])
-  usage_msg = usage_msg + "       %s <flow-id>\n" % (sys.argv[0])
-  usage_msg = usage_msg + "\n"
-  usage_msg = usage_msg + "    Arguments:\n"
-  usage_msg = usage_msg + "        <begin-flow-id> <end-flow-id>      Clear all flows in the flow ID range\n"
-  usage_msg = usage_msg + "        <flow-id>                          Clear a single flow with the flow ID\n"
-  usage_msg = usage_msg + "        all                                Clear all flows\n"
-
-  # app.debug = False;
-
-  # Usage info
-  if len(sys.argv) > 1 and (sys.argv[1] == "-h" or sys.argv[1] == "--help"):
-    print(usage_msg)
-    exit(0)
-
-  # Check arguments
-  if len(sys.argv) < 2:
-    log_error(usage_msg)
-    exit(1)
-
-  if (sys.argv[1] == "all"):
-    clear_flow_path(sys.argv[1])
-  else:
-    begin_flow_id = int(sys.argv[1], 0)
-    if len(sys.argv) >= 3:
-      end_flow_id = int(sys.argv[2], 0)
-    else:
-      end_flow_id = begin_flow_id
-
-    # Do the work
-    flow_id = begin_flow_id
-    while flow_id <= end_flow_id:
-      clear_flow_path(flow_id)
-      flow_id = flow_id + 1
diff --git a/web/ons-demo/js/app.js b/web/ons-demo/js/app.js
index 94c41e2..d869de7 100644
--- a/web/ons-demo/js/app.js
+++ b/web/ons-demo/js/app.js
@@ -1,6 +1,17 @@
 /*global d3, document∆*/
 
 
+function updateFlow(model) {
+    model.flows.forEach(function (flow) {
+	flow.flowId = flow.flowId.value;
+	flow.installerId = flow.installerId.value;
+	flow.dstDpid = flow.dataPath.dstPort.dpid.value;
+	flow.srcDpid = flow.dataPath.srcPort.dpid.value;
+	flow.dstPort = flow.dataPath.dstPort.port.value;
+	flow.srcPort = flow.dataPath.srcPort.port.value;
+    });
+}
+
 function sync() {
 	var d = Date.now();
 
@@ -8,6 +19,7 @@
 //		console.log('Update time: ' + (Date.now() - d)/1000 + 's');
 
 		if (newModel) {
+			updateFlow(newModel);
 			var modelChanged = false;
 			var newModelString = JSON.stringify(newModel);
 			if (!modelString || newModelString != modelString) {
diff --git a/web/pusher.py b/web/pusher.py
new file mode 100755
index 0000000..2a3528b
--- /dev/null
+++ b/web/pusher.py
@@ -0,0 +1,152 @@
+#! /usr/bin/env python
+
+
+import pprint
+import os
+import sys
+import subprocess
+import json
+import argparse
+import io
+import time
+
+from flask import Flask, json, Response, render_template, make_response, request
+
+## Global Var ##
+ControllerIP="127.0.0.1"
+ControllerPort=8080
+
+DEBUG=0
+pp = pprint.PrettyPrinter(indent=4)
+
+app = Flask(__name__)
+
+## Worker Functions ##
+def log_error(txt):
+  print '%s' % (txt)
+
+def debug(txt):
+  if DEBUG:
+    print '%s' % (txt)
+
+# @app.route("/wm/fprog/pusher/setrate/<dpid>/<rate>/json")
+# Sample output:
+#  "true"
+def set_rate(dpid,rate):
+  try:
+    command = "curl -s \"http://%s:%s/wm/fprog/pusher/setrate/%s/%s/json\"" % (ControllerIP, ControllerPort, dpid, rate)
+    debug("set_rate %s" % command)
+     
+    result = os.popen(command).read()
+    debug("result %s" % result)
+    if result == "false":
+      print "Failed to set rate"
+      return;
+  except:
+    log_error("Controller IF has issue")
+    exit(1)
+  
+  print "Sending rate to %s is successfully set to %s" % (dpid, rate)
+
+# @app.route("/wm/fprog/pusher/suspend/<dpid>/json")
+# Sample output:
+#  "true"
+def suspend(dpid):
+  try:
+    command = "curl -s \"http://%s:%s/wm/fprog/pusher/suspend/%s/json\"" % (ControllerIP, ControllerPort, dpid)
+    debug("suspend %s" % command)
+     
+    result = os.popen(command).read()
+    debug("result %s" % result)
+    if result == "false":
+      print "Failed to suspend"
+      return;
+  except:
+    log_error("Controller IF has issue")
+    exit(1)
+  
+  print "DPID %s is successfully suspended" % dpid
+
+# @app.route("/wm/fprog/pusher/resume/<dpid>/json")
+# Sample output:
+#  "true"
+def resume(dpid):
+  try:
+    command = "curl -s \"http://%s:%s/wm/fprog/pusher/resume/%s/json\"" % (ControllerIP, ControllerPort, dpid)
+    debug("resume %s" % command)
+     
+    result = os.popen(command).read()
+    debug("result %s" % result)
+    if result == "false":
+      print "Failed to resume"
+      return;
+  except:
+    log_error("Controller IF has issue")
+    exit(1)
+  
+  print "DPID %s is successfully resumed" % dpid
+
+# @app.route("/wm/fprog/pusher/barrier/<dpid>/json")
+# Sample output:
+#  "{"version":1,"type":"BARRIER_REPLY","length":8,"xid":4,"lengthU":8}"
+def barrier(dpid):
+  try:
+    command = "curl -s \"http://%s:%s/wm/fprog/pusher/barrier/%s/json\"" % (ControllerIP, ControllerPort, dpid)
+    debug("barrier %s" % command)
+     
+    result = os.popen(command).read()
+    debug("result %s" % result)
+    if result == "false":
+      print "Failed to send barrier"
+      return;
+  except:
+    log_error("Controller IF has issue")
+    exit(1)
+  
+  print "Barrier reply from %s : %s" % (dpid, result)
+
+
+if __name__ == "__main__":
+  usage_msg1 = "Usage:\n"
+  usage_msg2 = "%s rate <dpid> <rate> : Set sending rate[bytes/ms] to the switch\n" % (sys.argv[0])
+  usage_msg3 = "                   suspend <dpid>    : Suspend sending message to the switch\n"
+  usage_msg4 = "                   resume <dpid>     : Resume sending message to the switch\n"
+  usage_msg5 = "                   barrier <dpid>    : Send barrier message to the switch\n"
+  usage_msg = usage_msg1 + usage_msg2 + usage_msg3 + usage_msg4 + usage_msg5;
+
+  app.debug = True;
+
+  # Usage info
+  if len(sys.argv) > 1 and (sys.argv[1] == "-h" or sys.argv[1] == "--help"):
+    print(usage_msg)
+    exit(0)
+
+  # Check arguments
+  if len(sys.argv) < 2:
+    log_error(usage_msg)
+    exit(1)
+
+  # Do the work
+  if sys.argv[1] == "rate":
+    if len(sys.argv) < 4:
+      log_error(usage_msg)
+      exit(1)
+    set_rate(sys.argv[2], sys.argv[3])
+  elif sys.argv[1] == "suspend":
+    if len(sys.argv) < 3:
+      log_error(usage_msg)
+      exit(1)
+    suspend(sys.argv[2])
+  elif sys.argv[1] == "resume":
+    if len(sys.argv) < 3:
+      log_error(usage_msg)
+      exit(1)
+    resume(sys.argv[2])
+  elif sys.argv[1] == "barrier":
+    if len(sys.argv) < 3:
+      log_error(usage_msg)
+      exit(1)
+    barrier(sys.argv[2])
+  else:
+    log_error(usage_msg)
+    exit(1)
diff --git a/web/topology_rest.py b/web/topology_rest.py
index bac3113..b3a415e 100755
--- a/web/topology_rest.py
+++ b/web/topology_rest.py
@@ -720,8 +720,8 @@
 #    print "Debug: Controller command %s called %s" % (cmd, controller_name)
   else:
     # No longer use -i to specify keys (use .ssh/config to specify it)
-    start_onos="ssh %s ONOS/start-onos.sh start" % (controller_name)
-    stop_onos="ssh %s ONOS/start-onos.sh stop" % (controller_name)
+    start_onos="ssh %s \"cd ONOS; ./start-onos.sh start\"" % (controller_name)
+    stop_onos="ssh %s \"cd ONOS; ./start-onos.sh stop\"" % (controller_name)
 #    start_onos="ssh -i ~/.ssh/onlabkey.pem %s ONOS/start-onos.sh start" % (controller_name)
 #    stop_onos="ssh -i ~/.ssh/onlabkey.pem %s ONOS/start-onos.sh stop" % (controller_name)
 
@@ -960,7 +960,7 @@
   parsedResult = json.loads(result)
   if len(parsedResult) > 0:
     if parsedResult[-1].has_key('flowId'):
-      flow_nr = int(parsedResult[-1]['flowId'], 16)
+      flow_nr = int(parsedResult[-1]['flowId']['value'], 16)
   else:
     flow_nr = -1  # first flow
     print "first flow"