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 a67ce7a..a96f5dc 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowDatabaseOperation.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowDatabaseOperation.java
@@ -31,15 +31,11 @@
     /**
      * Add a flow.
      *
-     * @param flowManager the Flow Manager to use.
      * @param dbHandler the Graph Database handler to use.
      * @param flowPath the Flow Path to install.
-     * @param flowId the return-by-reference Flow ID as assigned internally.
      * @return true on success, otherwise false.
      */
-    static boolean addFlow(FlowManager flowManager,
-			   GraphDBOperation dbHandler,
-			   FlowPath flowPath, FlowId flowId) {
+    static boolean addFlow(GraphDBOperation dbHandler, FlowPath flowPath) {
 	IFlowPath flowObj = null;
 	boolean found = false;
 	try {
@@ -173,32 +169,25 @@
 	    if (flowEntry.flowEntryUserState() == FlowEntryUserState.FE_USER_DELETE)
 		continue;	// Skip: all Flow Entries were deleted earlier
 
-	    if (addFlowEntry(flowManager, dbHandler, flowObj, flowEntry) == null) {
+	    if (addFlowEntry(dbHandler, flowObj, flowEntry) == null) {
 		dbHandler.rollback();
 		return false;
 	    }
 	}
 	dbHandler.commit();
 
-	//
-	// TODO: We need a proper Flow ID allocation mechanism.
-	//
-	flowId.setValue(flowPath.flowId().value());
-
 	return true;
     }
 
     /**
      * Add a flow entry to the Network MAP.
      *
-     * @param flowManager the Flow Manager to use.
      * @param dbHandler the Graph Database handler to use.
      * @param flowObj the corresponding Flow Path object for the Flow Entry.
      * @param flowEntry the Flow Entry to install.
      * @return the added Flow Entry object on success, otherwise null.
      */
-    static IFlowEntry addFlowEntry(FlowManager flowManager,
-				   GraphDBOperation dbHandler,
+    static IFlowEntry addFlowEntry(GraphDBOperation dbHandler,
 				   IFlowPath flowObj,
 				   FlowEntry flowEntry) {
 	// Flow edges
@@ -507,91 +496,6 @@
     }
 
     /**
-     * Get all previously added flows by a specific installer for a given
-     * data path endpoints.
-     *
-     * @param dbHandler the Graph Database handler to use.
-     * @param installerId the Caller ID of the installer of the flow to get.
-     * @param dataPathEndpoints the data path endpoints of the flow to get.
-     * @return the Flow Paths if found, otherwise null.
-     */
-    static ArrayList<FlowPath> getAllFlows(GraphDBOperation dbHandler,
-					   CallerId installerId,
-					   DataPathEndpoints dataPathEndpoints) {
-	//
-	// TODO: The implementation below is not optimal:
-	// We fetch all flows, and then return only the subset that match
-	// the query conditions.
-	// We should use the appropriate Titan/Gremlin query to filter-out
-	// the flows as appropriate.
-	//
-	ArrayList<FlowPath> allFlows = getAllFlows(dbHandler);
-	ArrayList<FlowPath> flowPaths = new ArrayList<FlowPath>();
-
-	if (allFlows == null)
-	    return flowPaths;
-
-	for (FlowPath flow : allFlows) {
-	    //
-	    // TODO: String-based comparison is sub-optimal.
-	    // We are using it for now to save us the extra work of
-	    // implementing the "equals()" and "hashCode()" methods.
-	    //
-	    if (! flow.installerId().toString().equals(installerId.toString()))
-		continue;
-	    if (! flow.dataPath().srcPort().toString().equals(dataPathEndpoints.srcPort().toString())) {
-		continue;
-	    }
-	    if (! flow.dataPath().dstPort().toString().equals(dataPathEndpoints.dstPort().toString())) {
-		continue;
-	    }
-	    flowPaths.add(flow);
-	}
-
-	return flowPaths;
-    }
-
-    /**
-     * Get all installed flows by all installers for given data path endpoints.
-     *
-     * @param dbHandler the Graph Database handler to use.
-     * @param dataPathEndpoints the data path endpoints of the flows to get.
-     * @return the Flow Paths if found, otherwise null.
-     */
-    static ArrayList<FlowPath> getAllFlows(GraphDBOperation dbHandler,
-					   DataPathEndpoints dataPathEndpoints) {
-	//
-	// TODO: The implementation below is not optimal:
-	// We fetch all flows, and then return only the subset that match
-	// the query conditions.
-	// We should use the appropriate Titan/Gremlin query to filter-out
-	// the flows as appropriate.
-	//
-	ArrayList<FlowPath> flowPaths = new ArrayList<FlowPath>();
-	ArrayList<FlowPath> allFlows = getAllFlows(dbHandler);
-
-	if (allFlows == null)
-	    return flowPaths;
-
-	for (FlowPath flow : allFlows) {
-	    //
-	    // TODO: String-based comparison is sub-optimal.
-	    // We are using it for now to save us the extra work of
-	    // implementing the "equals()" and "hashCode()" methods.
-	    //
-	    if (! flow.dataPath().srcPort().toString().equals(dataPathEndpoints.srcPort().toString())) {
-		continue;
-	    }
-	    if (! flow.dataPath().dstPort().toString().equals(dataPathEndpoints.dstPort().toString())) {
-		continue;
-	    }
-	    flowPaths.add(flow);
-	}
-
-	return flowPaths;
-    }
-
-    /**
      * Get summary of all installed flows by all installers in a given range.
      *
      * @param dbHandler the Graph Database handler to use.
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 feb80e1..47ef3b7 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowEventHandler.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowEventHandler.java
@@ -32,19 +32,6 @@
 import org.slf4j.LoggerFactory;
 
 /**
- * A class for storing a pair of Flow Path and a Flow Entry.
- */
-class FlowPathEntryPair {
-    protected FlowPath flowPath;
-    protected FlowEntry flowEntry;
-
-    protected FlowPathEntryPair(FlowPath flowPath, FlowEntry flowEntry) {
-	this.flowPath = flowPath;
-	this.flowEntry = flowEntry;
-    }
-}
-
-/**
  * Class for FlowPath Maintenance.
  * This class listens for FlowEvents to:
  * - Maintain a local cache of the Network Topology.
@@ -207,7 +194,7 @@
      * Process the events (if any)
      */
     private void processEvents() {
-	List<FlowPathEntryPair> modifiedFlowEntries;
+	Collection<FlowEntry> modifiedFlowEntries;
 
 	if (topologyEvents.isEmpty() && flowPathEvents.isEmpty() &&
 	    flowEntryEvents.isEmpty()) {
@@ -225,17 +212,16 @@
 	}
 
 	// Extract the modified Flow Entries
-	modifiedFlowEntries = extractModifiedFlowEntries(modifiedFlowPaths);
+	modifiedFlowEntries = extractModifiedFlowEntries(modifiedFlowPaths.values());
 
 	// Assign missing Flow Entry IDs
 	assignFlowEntryId(modifiedFlowEntries);
 
 	//
-	// Push the modified Flow Entries to switches, datagrid and database
+	// Push the modified state to the Flow Manager
 	//
-	flowManager.pushModifiedFlowEntriesToSwitches(modifiedFlowEntries);
-	flowManager.pushModifiedFlowEntriesToDatagrid(modifiedFlowEntries);
-	flowManager.pushModifiedFlowPathsToDatabase(modifiedFlowPaths.values());
+	flowManager.pushModifiedFlowState(modifiedFlowPaths.values(),
+					  modifiedFlowEntries);
 
 	//
 	// Remove Flow Entries that were deleted
@@ -254,20 +240,20 @@
 
     /**
      * Extract the modified Flow Entries.
+     *
+     * @param modifiedFlowPaths the Flow Paths to process.
+     * @return a collection with the modified Flow Entries.
      */
-    private List<FlowPathEntryPair> extractModifiedFlowEntries(
-				Map<Long, FlowPath> modifiedFlowPaths) {
-	List<FlowPathEntryPair> modifiedFlowEntries =
-	    new LinkedList<FlowPathEntryPair>();
+    private Collection<FlowEntry> extractModifiedFlowEntries(
+			Collection<FlowPath> modifiedFlowPaths) {
+	List<FlowEntry> modifiedFlowEntries = new LinkedList<FlowEntry>();
 
 	// Extract only the modified Flow Entries
-	for (FlowPath flowPath : modifiedFlowPaths.values()) {
+	for (FlowPath flowPath : modifiedFlowPaths) {
 	    for (FlowEntry flowEntry : flowPath.flowEntries()) {
 		if (flowEntry.flowEntrySwitchState() ==
 		    FlowEntrySwitchState.FE_SWITCH_NOT_UPDATED) {
-		    FlowPathEntryPair flowPair =
-			new FlowPathEntryPair(flowPath, flowEntry);
-		    modifiedFlowEntries.add(flowPair);
+		    modifiedFlowEntries.add(flowEntry);
 		}
 	    }
 	}
@@ -276,8 +262,11 @@
 
     /**
      * Assign the Flow Entry ID as needed.
+     *
+     * @param modifiedFlowEnries the collection of Flow Entries that need
+     * Flow Entry ID assigned.
      */
-    private void assignFlowEntryId(List<FlowPathEntryPair> modifiedFlowEntries) {
+    private void assignFlowEntryId(Collection<FlowEntry> modifiedFlowEntries) {
 	if (modifiedFlowEntries.isEmpty())
 	    return;
 
@@ -286,9 +275,7 @@
 	//
 	// Assign the Flow Entry ID only for Flow Entries for my switches
 	//
-	for (FlowPathEntryPair flowPair : modifiedFlowEntries) {
-	    FlowEntry flowEntry = flowPair.flowEntry;
-	    // Update the Flow Entries only for my switches
+	for (FlowEntry flowEntry : modifiedFlowEntries) {
 	    IOFSwitch mySwitch = mySwitches.get(flowEntry.dpid().value());
 	    if (mySwitch == null)
 		continue;
@@ -412,7 +399,6 @@
      * Process the Flow Entry events.
      */
     private void processFlowEntryEvents() {
-	FlowPathEntryPair flowPair;
 	FlowPath flowPath;
 	FlowEntry updatedFlowEntry;
 
@@ -431,7 +417,6 @@
 					 flowEntry);
 		    continue;
 		}
-		flowPair = new FlowPathEntryPair(flowPath, updatedFlowEntry);
 		modifiedFlowPaths.put(flowPath.flowId().value(), flowPath);
 	    }
 	    unmatchedFlowEntryAdd = remainingUpdates;
@@ -468,7 +453,6 @@
 		    break;
 		}
 		// Add the updated entry to the list of updated Flow Entries
-		flowPair = new FlowPathEntryPair(flowPath, updatedFlowEntry);
 		modifiedFlowPaths.put(flowPath.flowId().value(), flowPath);
 		break;
 
@@ -488,7 +472,6 @@
 		    // Flow Entry not found: ignore it
 		    break;
 		}
-		flowPair = new FlowPathEntryPair(flowPath, updatedFlowEntry);
 		modifiedFlowPaths.put(flowPath.flowId().value(), flowPath);
 		break;
 	    }
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 7f43fe9..f4b1f8f 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowManager.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowManager.java
@@ -4,6 +4,7 @@
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.LinkedList;
+import java.util.List;
 import java.util.Map;
 import java.util.Random;
 import java.util.concurrent.BlockingQueue;
@@ -210,11 +211,17 @@
      * Add a flow.
      *
      * @param flowPath the Flow Path to install.
-     * @param flowId the return-by-reference Flow ID as assigned internally.
-     * @return true on success, otherwise false.
+     * @return the Flow ID on success, otherwise null.
      */
     @Override
-    public boolean addFlow(FlowPath flowPath, FlowId flowId) {
+    public FlowId addFlow(FlowPath flowPath) {
+
+	// Allocate the Flow ID if necessary
+	if (! flowPath.flowId().isValid()) {
+	    long id = getNextFlowEntryId();
+	    flowPath.setFlowId(new FlowId(id));
+	}
+
 	//
 	// NOTE: We need to explicitly initialize some of the state,
 	// in case the application didn't do it.
@@ -228,35 +235,11 @@
 		flowEntry.setFlowId(new FlowId(flowPath.flowId().value()));
 	}
 
-	if (FlowDatabaseOperation.addFlow(this, dbHandlerApi, flowPath, flowId)) {
+	if (FlowDatabaseOperation.addFlow(dbHandlerApi, flowPath)) {
 	    datagridService.notificationSendFlowAdded(flowPath);
-	    return true;
+	    return flowPath.flowId();
 	}
-	return false;
-    }
-
-    /**
-     * Add a flow entry to the Network MAP.
-     *
-     * @param flowObj the corresponding Flow Path object for the Flow Entry.
-     * @param flowEntry the Flow Entry to install.
-     * @return the added Flow Entry object on success, otherwise null.
-     */
-    private IFlowEntry addFlowEntry(IFlowPath flowObj, FlowEntry flowEntry) {
-	return FlowDatabaseOperation.addFlowEntry(this, dbHandlerInner,
-						  flowObj, flowEntry);
-    }
-
-    /**
-     * Delete a flow entry from the Network MAP.
-     *
-     * @param flowObj the corresponding Flow Path object for the Flow Entry.
-     * @param flowEntry the Flow Entry to delete.
-     * @return true on success, otherwise false.
-     */
-    private boolean deleteFlowEntry(IFlowPath flowObj, FlowEntry flowEntry) {
-	return FlowDatabaseOperation.deleteFlowEntry(dbHandlerInner,
-						     flowObj, flowEntry);
+	return null;
     }
 
     /**
@@ -310,33 +293,6 @@
     }
 
     /**
-     * Get all previously added flows by a specific installer for a given
-     * data path endpoints.
-     *
-     * @param installerId the Caller ID of the installer of the flow to get.
-     * @param dataPathEndpoints the data path endpoints of the flow to get.
-     * @return the Flow Paths if found, otherwise null.
-     */
-    @Override
-    public ArrayList<FlowPath> getAllFlows(CallerId installerId,
-					   DataPathEndpoints dataPathEndpoints) {
-	return FlowDatabaseOperation.getAllFlows(dbHandlerApi, installerId,
-						 dataPathEndpoints);
-    }
-
-    /**
-     * Get all installed flows by all installers for given data path endpoints.
-     *
-     * @param dataPathEndpoints the data path endpoints of the flows to get.
-     * @return the Flow Paths if found, otherwise null.
-     */
-    @Override
-    public ArrayList<FlowPath> getAllFlows(DataPathEndpoints dataPathEndpoints) {
-	return FlowDatabaseOperation.getAllFlows(dbHandlerApi,
-						 dataPathEndpoints);
-    }
-
-    /**
      * Get summary of all installed flows by all installers in a given range.
      *
      * @param flowId the Flow ID of the first flow in the flow range to get.
@@ -349,29 +305,6 @@
 	return FlowDatabaseOperation.getAllFlowsSummary(dbHandlerApi, flowId,
 							maxFlows);
     }
-    
-    /**
-     * Add and maintain a shortest-path flow.
-     *
-     * NOTE: The Flow Path argument does NOT contain flow entries.
-     *
-     * @param flowPath the Flow Path with the endpoints and the match
-     * conditions to install.
-     * @return the added shortest-path flow on success, otherwise null.
-     */
-    @Override
-    public FlowPath addAndMaintainShortestPathFlow(FlowPath flowPath) {
-	//
-	// Don't do the shortest path computation here.
-	// Instead, let the Flow reconciliation thread take care of it.
-	//
-
-	FlowId flowId = new FlowId();
-	if (! addFlow(flowPath, flowId))
-	    return null;
-
-	return (flowPath);
-    }
 
     /**
      * Get the collection of my switches.
@@ -402,6 +335,63 @@
     }
 
     /**
+     * Inform the Flow Manager that a collection of Flow Entries have been
+     * pushed to a switch.
+     *
+     * @param entries the collection of <IOFSwitch, FlowEntry> pairs
+     * that have been pushed.
+     */
+    public void flowEntriesPushedToSwitch(
+		Collection<Pair<IOFSwitch, FlowEntry>> entries) {
+
+	//
+	// Process all entries
+	//
+	for (Pair<IOFSwitch, FlowEntry> entry : entries) {
+	    IOFSwitch sw = entry.first;
+	    FlowEntry flowEntry = entry.second;
+
+	    //
+	    // Mark the Flow Entry that it has been pushed to the switch
+	    //
+	    flowEntry.setFlowEntrySwitchState(FlowEntrySwitchState.FE_SWITCH_UPDATED);
+
+	    //
+	    // Write the Flow Entry to the Datagrid
+	    //
+	    switch (flowEntry.flowEntryUserState()) {
+	    case FE_USER_ADD:
+		datagridService.notificationSendFlowEntryAdded(flowEntry);
+		break;
+	    case FE_USER_MODIFY:
+		datagridService.notificationSendFlowEntryUpdated(flowEntry);
+		break;
+	    case FE_USER_DELETE:
+		datagridService.notificationSendFlowEntryRemoved(flowEntry.flowEntryId());
+		break;
+	    }
+	}
+    }
+
+    /**
+     * Push modified Flow-related state as appropriate.
+     *
+     * @param modifiedFlowPaths the collection of modified Flow Paths.
+     * @param modifiedFlowEntries the collection of modified Flow Entries.
+     */
+    void pushModifiedFlowState(Collection<FlowPath> modifiedFlowPaths,
+			       Collection<FlowEntry> modifiedFlowEntries) {
+	//
+	// Push the modified Flow state:
+	//  - Flow Entries to switches and the datagrid
+	//  - Flow Paths to the database
+	//
+	pushModifiedFlowEntriesToSwitches(modifiedFlowEntries);
+	pushModifiedFlowPathsToDatabase(modifiedFlowPaths);
+	cleanupDeletedFlowEntriesFromDatagrid(modifiedFlowEntries);
+    }
+
+    /**
      * Push modified Flow Entries to switches.
      *
      * NOTE: Only the Flow Entries to switches controlled by this instance
@@ -409,99 +399,88 @@
      *
      * @param modifiedFlowEntries the collection of modified Flow Entries.
      */
-    public void pushModifiedFlowEntriesToSwitches(
-			Collection<FlowPathEntryPair> modifiedFlowEntries) {
+    private void pushModifiedFlowEntriesToSwitches(
+			Collection<FlowEntry> modifiedFlowEntries) {
 	if (modifiedFlowEntries.isEmpty())
 	    return;
 
+	List<Pair<IOFSwitch, FlowEntry>> entries =
+	    new LinkedList<Pair<IOFSwitch, FlowEntry>>();
+
 	Map<Long, IOFSwitch> mySwitches = getMySwitches();
 
-	for (FlowPathEntryPair flowPair : modifiedFlowEntries) {
-	    FlowEntry flowEntry = flowPair.flowEntry;
-
+	//
+	// Create a collection of my Flow Entries to push
+	//
+	for (FlowEntry flowEntry : modifiedFlowEntries) {
 	    IOFSwitch mySwitch = mySwitches.get(flowEntry.dpid().value());
 	    if (mySwitch == null)
 		continue;
 
-	    log.debug("Pushing Flow Entry To Switch: {}", flowEntry.toString());
-
 	    //
-	    // Push the Flow Entry into the switch
+	    // Assign Flow Entry IDs if missing.
 	    //
-	    if (! pusher.add(mySwitch, flowEntry)) {
-		String logMsg = "Cannot install Flow Entry " +
-		    flowEntry.flowEntryId() +
-		    " from Flow Path " + flowEntry.flowId() +
-		    " on switch " + flowEntry.dpid();
-		log.error(logMsg);
-		continue;
+	    // NOTE: This is an additional safeguard, in case the
+	    // mySwitches set has changed (after the Flow Entry IDs
+	    // assignments by the caller).
+	    //
+	    if (! flowEntry.isValidFlowEntryId()) {
+		long id = getNextFlowEntryId();
+		flowEntry.setFlowEntryId(new FlowEntryId(id));
 	    }
 
-	    //
-	    // NOTE: Here we assume that the switch has been
-	    // successfully updated.
-	    //
-	    flowEntry.setFlowEntrySwitchState(FlowEntrySwitchState.FE_SWITCH_UPDATED);
+	    log.debug("Pushing Flow Entry To Switch: {}", flowEntry.toString());
+	    entries.add(new Pair<IOFSwitch, FlowEntry>(mySwitch, flowEntry));
 	}
+
+	pusher.pushFlowEntries(entries);
     }
 
     /**
-     * Push modified Flow Entries to the datagrid.
+     * Cleanup deleted Flow Entries from the datagrid.
+     *
+     * NOTE: We cleanup only the Flow Entries that are not for our switches.
+     * This is needed to handle the case a switch going down:
+     * It has no Master controller instance, hence no controller instance
+     * will cleanup its flow entries.
+     * This is sub-optimal: we need to elect a controller instance to handle
+     * the cleanup of such orphaned flow entries.
      *
      * @param modifiedFlowEntries the collection of modified Flow Entries.
      */
-    public void pushModifiedFlowEntriesToDatagrid(
-			Collection<FlowPathEntryPair> modifiedFlowEntries) {
+    private void cleanupDeletedFlowEntriesFromDatagrid(
+			Collection<FlowEntry> modifiedFlowEntries) {
 	if (modifiedFlowEntries.isEmpty())
 	    return;
 
 	Map<Long, IOFSwitch> mySwitches = getMySwitches();
 
-	for (FlowPathEntryPair flowPair : modifiedFlowEntries) {
-	    FlowEntry flowEntry = flowPair.flowEntry;
-
+	for (FlowEntry flowEntry : modifiedFlowEntries) {
+	    //
+	    // Process only Flow Entries that should be deleted and have
+	    // a valid Flow Entry ID.
+	    //
 	    if (! flowEntry.isValidFlowEntryId())
 		continue;
-
-	    IOFSwitch mySwitch = mySwitches.get(flowEntry.dpid().value());
-
-	    //
-	    // TODO: For now Flow Entries are removed by all instances,
-	    // even if this Flow Entry is not for our switches.
-	    //
-	    // This is needed to handle the case a switch going down:
-	    // it has no Master controller instance, hence no
-	    // controller instance will cleanup its flow entries.
-	    // This is sub-optimal: we need to elect a controller
-	    // instance to handle the cleanup of such orphaned flow
-	    // entries.
-	    //
-	    if (mySwitch == null) {
-		if (flowEntry.flowEntryUserState() !=
-		    FlowEntryUserState.FE_USER_DELETE) {
-		    continue;
-		}
+	    if (flowEntry.flowEntryUserState() !=
+		FlowEntryUserState.FE_USER_DELETE) {
+		continue;
 	    }
 
-	    log.debug("Pushing Flow Entry To Datagrid: {}", flowEntry.toString());
+	    //
+	    // NOTE: The deletion of Flow Entries for my switches is handled
+	    // elsewhere.
+	    //
+	    IOFSwitch mySwitch = mySwitches.get(flowEntry.dpid().value());
+	    if (mySwitch != null)
+		continue;
+
+	    log.debug("Pushing cleanup of Flow Entry To Datagrid: {}", flowEntry.toString());
+
 	    //
 	    // Write the Flow Entry to the Datagrid
 	    //
-	    switch (flowEntry.flowEntryUserState()) {
-	    case FE_USER_ADD:
-		if (mySwitch == null)
-		    break;	// Install only flow entries for my switches
-		datagridService.notificationSendFlowEntryAdded(flowEntry);
-		break;
-	    case FE_USER_MODIFY:
-		if (mySwitch == null)
-		    break;	// Install only flow entries for my switches
-		datagridService.notificationSendFlowEntryUpdated(flowEntry);
-		break;
-	    case FE_USER_DELETE:
-		datagridService.notificationSendFlowEntryRemoved(flowEntry.flowEntryId());
-		break;
-	    }
+	    datagridService.notificationSendFlowEntryRemoved(flowEntry.flowEntryId());
 	}
     }
 
@@ -556,7 +535,7 @@
      *
      * @param modifiedFlowPaths the collection of Flow Paths to push.
      */
-    void pushModifiedFlowPathsToDatabase(
+    private void pushModifiedFlowPathsToDatabase(
 		Collection<FlowPath> modifiedFlowPaths) {
 	//
 	// We only add the Flow Paths to the Database Queue.
@@ -579,8 +558,6 @@
 	if (modifiedFlowPaths.isEmpty())
 	    return;
 
-	FlowId dummyFlowId = new FlowId();
-
 	Map<Long, IOFSwitch> mySwitches = getMySwitches();
 
 	for (FlowPath flowPath : modifiedFlowPaths) {
@@ -594,6 +571,27 @@
 		continue;
 
 	    //
+	    // Delete the Flow Path from the Network Map
+	    //
+	    if (flowPath.flowPathUserState() ==
+		FlowPathUserState.FP_USER_DELETE) {
+		log.debug("Deleting Flow Path From Database: {}",
+			  flowPath.toString());
+
+		try {
+		    if (! FlowDatabaseOperation.deleteFlow(
+					dbHandlerInner,
+					flowPath.flowId())) {
+			log.error("Cannot delete Flow Path {} from Network Map",
+				  flowPath.flowId());
+		    }
+		} catch (Exception e) {
+		    log.error("Exception deleting Flow Path from Network MAP: {}", e);
+		}
+		continue;
+	    }
+
+	    //
 	    // Test whether all Flow Entries are valid
 	    //
 	    boolean allValid = true;
@@ -616,8 +614,7 @@
 	    // Write the Flow Path to the Network Map
 	    //
 	    try {
-		if (! FlowDatabaseOperation.addFlow(this, dbHandlerInner,
-						    flowPath, dummyFlowId)) {
+		if (! FlowDatabaseOperation.addFlow(dbHandlerInner, flowPath)) {
 		    String logMsg = "Cannot write to Network Map Flow Path " +
 			flowPath.flowId();
 		    log.error(logMsg);
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 8d2b797..a25602d 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/IFlowService.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/IFlowService.java
@@ -1,15 +1,18 @@
 package net.onrc.onos.ofcontroller.flowmanager;
 
 import java.util.ArrayList;
+import java.util.Collection;
 
 import net.floodlightcontroller.core.IOFSwitch;
 import net.floodlightcontroller.core.module.IFloodlightService;
 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.FlowEntry;
 import net.onrc.onos.ofcontroller.util.FlowEntryId;
 import net.onrc.onos.ofcontroller.util.FlowId;
 import net.onrc.onos.ofcontroller.util.FlowPath;
+import net.onrc.onos.ofcontroller.util.Pair;
 
 /**
  * Interface for providing Flow Service to other modules.
@@ -18,14 +21,10 @@
     /**
      * Add a flow.
      *
-     * Internally, ONOS will automatically register the installer for
-     * receiving Flow Path Notifications for that path.
-     *
      * @param flowPath the Flow Path to install.
-     * @param flowId the return-by-reference Flow ID as assigned internally.
-     * @return true on success, otherwise false.
+     * @return the Flow ID on success, otherwise null.
      */
-    boolean addFlow(FlowPath flowPath, FlowId flowId);
+    FlowId addFlow(FlowPath flowPath);
 
     /**
      * Delete all previously added flows.
@@ -58,25 +57,6 @@
     ArrayList<FlowPath> getAllFlows();
 
     /**
-     * Get all previously added flows by a specific installer for a given
-     * data path endpoints.
-     *
-     * @param installerId the Caller ID of the installer of the flow to get.
-     * @param dataPathEndpoints the data path endpoints of the flow to get.
-     * @return the Flow Paths if found, otherwise null.
-     */
-    ArrayList<FlowPath> getAllFlows(CallerId installerId,
-				 DataPathEndpoints dataPathEndpoints);
-
-    /**
-     * Get all installed flows by all installers for given data path endpoints.
-     *
-     * @param dataPathEndpoints the data path endpoints of the flows to get.
-     * @return the Flow Paths if found, otherwise null.
-     */
-    ArrayList<FlowPath> getAllFlows(DataPathEndpoints dataPathEndpoints);
-
-    /**
      * Get summary of all installed flows by all installers.
      *
      * @param flowId starting flow Id of the range
@@ -84,21 +64,6 @@
      * @return the Flow Paths if found, otherwise null.
      */
     ArrayList<FlowPath> getAllFlowsSummary(FlowId flowId, int maxFlows);
-    
-    /**
-     * Add and maintain a shortest-path flow.
-     *
-     * NOTE: The Flow Path argument does NOT contain all flow entries.
-     * Instead, it contains a single dummy flow entry that is used to
-     * store the matching condition(s).
-     * That entry is replaced by the appropriate entries from the
-     * internally performed shortest-path computation.
-     *
-     * @param flowPath the Flow Path with the endpoints and the match
-     * conditions to install.
-     * @return the added shortest-path flow on success, otherwise null.
-     */
-    FlowPath addAndMaintainShortestPathFlow(FlowPath flowPath);
 
     /**
      * Get the network topology.
@@ -106,7 +71,7 @@
      * @return the network topology.
      */
     Topology getTopology();
-    
+
     /**
      * Get a globally unique flow ID from the flow service.
      * NOTE: Not currently guaranteed to be globally unique.
@@ -122,4 +87,14 @@
      * @param flowEntryId the Flow Entry ID of the expired Flow Entry.
      */
     public void flowEntryOnSwitchExpired(IOFSwitch sw, FlowEntryId flowEntryId);
+
+    /**
+     * Inform the Flow Manager that a collection of Flow Entries have been
+     * pushed to a switch.
+     *
+     * @param entries the collection of <IOFSwitch, FlowEntry> pairs
+     * that have been pushed.
+     */
+    public void flowEntriesPushedToSwitch(
+			Collection<Pair<IOFSwitch, FlowEntry>> entries);
 }
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/AddFlowResource.java b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/AddFlowResource.java
index 0926f91..9afaaec 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/AddFlowResource.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/AddFlowResource.java
@@ -64,9 +64,9 @@
 
 	// Process the request
 	if (flowPath != null) {
-	    if (flowService.addFlow(flowPath, result) != true) {
-		result = new FlowId();		// Error: Return empty Flow Id
-	    }
+	    FlowId addedFlowId = flowService.addFlow(flowPath);
+	    if (addedFlowId != null)
+		result = addedFlowId;
 	}
 
         return result;
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/AddShortestPathFlowResource.java b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/AddShortestPathFlowResource.java
index 7a4e88c..4d03623 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/AddShortestPathFlowResource.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/AddShortestPathFlowResource.java
@@ -64,13 +64,9 @@
 
 	// Process the request
 	if (flowPath != null) {
-	    FlowPath addedFlowPath =
-		flowService.addAndMaintainShortestPathFlow(flowPath);
-	    if (addedFlowPath == null) {
-		result = new FlowId();		// Error: Return empty Flow Id
-	    } else {
-		result = addedFlowPath.flowId();
-	    }
+	    FlowId addedFlowId = flowService.addFlow(flowPath);
+	    if (addedFlowId != null)
+		result = addedFlowId;
 	}
 
         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 81d26dd..c358263 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
@@ -20,8 +20,6 @@
         router.attach("/add-shortest-path/json", AddShortestPathFlowResource.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);
-        router.attach("/getall-by-endpoints/{src-dpid}/{src-port}/{dst-dpid}/{dst-port}/json", GetAllFlowsByEndpointsResource.class);
         router.attach("/getall/json", GetAllFlowsResource.class);
         router.attach("/getsummary/{flow-id}/{max-flows}/json", GetSummaryFlowsResource.class);
         return router;
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/GetAllFlowsByEndpointsResource.java b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/GetAllFlowsByEndpointsResource.java
deleted file mode 100644
index 1ac98c0..0000000
--- a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/GetAllFlowsByEndpointsResource.java
+++ /dev/null
@@ -1,75 +0,0 @@
-package net.onrc.onos.ofcontroller.flowmanager.web;
-
-import java.util.ArrayList;
-
-import net.onrc.onos.ofcontroller.flowmanager.IFlowService;
-import net.onrc.onos.ofcontroller.util.DataPathEndpoints;
-import net.onrc.onos.ofcontroller.util.Dpid;
-import net.onrc.onos.ofcontroller.util.FlowPath;
-import net.onrc.onos.ofcontroller.util.Port;
-import net.onrc.onos.ofcontroller.util.SwitchPort;
-
-import org.restlet.resource.Get;
-import org.restlet.resource.ServerResource;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-/**
- * Flow Manager REST API implementation: Get all Flow state for given
- * source and destination switches and ports.
- *
- * The "{src-dpid}" request attribute value is the source DPID of the flows to
- * get.
- * The "{src-port}" request attribute value is the source port of the flows to
- * get.
- * The "{dst-dpid}" request attribute value is the destination DPID of the
- * flows to get.
- * The "{dst-port}" request attribute value is the destination port of the
- * flows to get.
- *
- *   GET /wm/flow/getall-by-endpoints/{src-dpid}/{src-port}/{dst-dpid}/{dst-port}/json"
- */
-public class GetAllFlowsByEndpointsResource extends ServerResource {
-    protected final static Logger log = LoggerFactory.getLogger(GetAllFlowsByEndpointsResource.class);
-
-    /**
-     * Implement the API.
-     *
-     * @return the collection of Flow states if any found, otherwise null.
-     */
-    @Get("json")
-    public ArrayList<FlowPath> retrieve() {
-	ArrayList<FlowPath> result = null;
-
-        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 srcDpidStr = (String) getRequestAttributes().get("src-dpid");
-        String srcPortStr = (String) getRequestAttributes().get("src-port");
-        String dstDpidStr = (String) getRequestAttributes().get("dst-dpid");
-        String dstPortStr = (String) getRequestAttributes().get("dst-port");
-
-	log.debug("Get All Flows Endpoints: " + srcDpidStr + "--" +
-		  srcPortStr + "--" + dstDpidStr + "--" + dstPortStr);
-
-	Dpid srcDpid = new Dpid(srcDpidStr);
-	Port srcPort = new Port(Short.parseShort(srcPortStr));
-	Dpid dstDpid = new Dpid(dstDpidStr);
-	Port dstPort = new Port(Short.parseShort(dstPortStr));
-	SwitchPort srcSwitchPort = new SwitchPort(srcDpid, srcPort);
-	SwitchPort dstSwitchPort = new SwitchPort(dstDpid, dstPort);
-	DataPathEndpoints dataPathEndpoints =
-	    new DataPathEndpoints(srcSwitchPort, dstSwitchPort);
-
-	result = flowService.getAllFlows(dataPathEndpoints);
-
-        return result;
-    }
-}
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/GetAllFlowsByInstallerIdResource.java b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/GetAllFlowsByInstallerIdResource.java
deleted file mode 100644
index 870548e..0000000
--- a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/web/GetAllFlowsByInstallerIdResource.java
+++ /dev/null
@@ -1,82 +0,0 @@
-package net.onrc.onos.ofcontroller.flowmanager.web;
-
-import java.util.ArrayList;
-
-import net.onrc.onos.ofcontroller.flowmanager.IFlowService;
-import net.onrc.onos.ofcontroller.util.CallerId;
-import net.onrc.onos.ofcontroller.util.DataPathEndpoints;
-import net.onrc.onos.ofcontroller.util.Dpid;
-import net.onrc.onos.ofcontroller.util.FlowPath;
-import net.onrc.onos.ofcontroller.util.Port;
-import net.onrc.onos.ofcontroller.util.SwitchPort;
-
-import org.restlet.resource.Get;
-import org.restlet.resource.ServerResource;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-/**
- * Flow Manager REST API implementation: Get all Flow state for a given
- * Installer ID and given source and destination switches and ports.
- *
- * The "{installer-id}" request attribute value is the Installer ID of the
- * flows to get.
- * The "{src-dpid}" request attribute value is the source DPID of the flows to
- * get.
- * The "{src-port}" request attribute value is the source port of the flows to
- * get.
- * The "{dst-dpid}" request attribute value is the destination DPID of the
- * flows to get.
- * The "{dst-port}" request attribute value is the destination port of the
- * flows to get.
- *
- *   GET /wm/flow/getall-by-installer-id/{installer-id}/{src-dpid}/{src-port}/{dst-dpid}/{dst-port}/json"
- */
-public class GetAllFlowsByInstallerIdResource extends ServerResource {
-    protected final static Logger log = LoggerFactory.getLogger(GetAllFlowsByInstallerIdResource.class);
-
-    /**
-     * Implement the API.
-     *
-     * @return the collection of Flow states if any found, otherwise null.
-     */
-    @Get("json")
-    public ArrayList<FlowPath> retrieve() {
-	ArrayList<FlowPath> result = null;
-
-        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 installerIdStr = (String) getRequestAttributes().get("installer-id");
-        String srcDpidStr = (String) getRequestAttributes().get("src-dpid");
-        String srcPortStr = (String) getRequestAttributes().get("src-port");
-        String dstDpidStr = (String) getRequestAttributes().get("dst-dpid");
-        String dstPortStr = (String) getRequestAttributes().get("dst-port");
-
-	log.debug("Get All Flow By Installer: " + installerIdStr +
-		  " Endpoints: " +
-		  srcDpidStr + "--" + srcPortStr + "--" +
-		  dstDpidStr + "--" + dstPortStr);
-
-	CallerId installerId = new CallerId(installerIdStr);
-	Dpid srcDpid = new Dpid(srcDpidStr);
-	Port srcPort = new Port(Short.parseShort(srcPortStr));
-	Dpid dstDpid = new Dpid(dstDpidStr);
-	Port dstPort = new Port(Short.parseShort(dstPortStr));
-	SwitchPort srcSwitchPort = new SwitchPort(srcDpid, srcPort);
-	SwitchPort dstSwitchPort = new SwitchPort(dstDpid, dstPort);
-	DataPathEndpoints dataPathEndpoints =
-	    new DataPathEndpoints(srcSwitchPort, dstSwitchPort);
-
-	result = flowService.getAllFlows(installerId, dataPathEndpoints);
-
-        return result;
-    }
-}
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 438f478..c3c7107 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowPusher.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowPusher.java
@@ -3,9 +3,11 @@
 import java.io.IOException;
 import java.util.ArrayDeque;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.EnumSet;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -27,6 +29,7 @@
 import net.floodlightcontroller.threadpool.IThreadPoolService;
 import net.floodlightcontroller.util.MACAddress;
 import net.floodlightcontroller.util.OFMessageDamper;
+import net.onrc.onos.ofcontroller.flowmanager.IFlowService;
 import net.onrc.onos.ofcontroller.util.FlowEntryAction;
 import net.onrc.onos.ofcontroller.util.FlowEntryAction.*;
 import net.onrc.onos.ofcontroller.util.FlowEntry;
@@ -35,6 +38,7 @@
 import net.onrc.onos.ofcontroller.util.FlowEntryMatch;
 import net.onrc.onos.ofcontroller.util.FlowEntryUserState;
 import net.onrc.onos.ofcontroller.util.IPv4Net;
+import net.onrc.onos.ofcontroller.util.Pair;
 import net.onrc.onos.ofcontroller.util.Port;
 
 /**
@@ -51,6 +55,7 @@
  */
 public class FlowPusher implements IFlowPusherService, IOFMessageListener {
     private final static Logger log = LoggerFactory.getLogger(FlowPusher.class);
+    protected volatile IFlowService flowManager;
 
     // NOTE: Below are moved from FlowManager.
     // TODO: Values copied from elsewhere (class LearningSwitch).
@@ -267,6 +272,7 @@
 		this.threadPool = modContext.getServiceImpl(IThreadPoolService.class);
 		IFloodlightProviderService flservice = modContext.getServiceImpl(IFloodlightProviderService.class);
 		flservice.addOFMessageListener(OFType.BARRIER_REPLY, this);
+		flowManager = modContext.getServiceImpl(IFlowService.class);
 		
 		if (damper != null) {
 			messageDamper = damper;
@@ -443,9 +449,46 @@
 
 		return true;
 	}
-	
+
 	@Override
-	public boolean add(IOFSwitch sw, FlowEntry flowEntry) {
+	public void pushFlowEntries(
+		Collection<Pair<IOFSwitch, FlowEntry>> entries) {
+
+		List<Pair<IOFSwitch, FlowEntry>> pushedEntries =
+			new LinkedList<Pair<IOFSwitch, FlowEntry>>();
+
+		for (Pair<IOFSwitch, FlowEntry> entry : entries) {
+			if (add(entry.first, entry.second)) {
+				pushedEntries.add(entry);
+			}
+		}
+
+		//
+		// 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.
+		// Only after inform the Flow Manager that the entry is pushed.
+		//
+		flowManager.flowEntriesPushedToSwitch(pushedEntries);
+	}
+
+	@Override
+	public void pushFlowEntry(IOFSwitch sw, FlowEntry flowEntry) {
+	    Collection<Pair<IOFSwitch, FlowEntry>> entries = 
+		new LinkedList<Pair<IOFSwitch, FlowEntry>>();
+
+	    entries.add(new Pair<IOFSwitch, FlowEntry>(sw, flowEntry));
+	    pushFlowEntries(entries);
+	}
+
+	/**
+	 * 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.
+	 */
+	private boolean add(IOFSwitch sw, FlowEntry flowEntry) {
 		//
 		// Create the OpenFlow Flow Modification Entry to push
 		//
@@ -709,17 +752,7 @@
 				+ matchSrcMac + " dstMac: " + matchDstMac + " inPort: "
 				+ matchInPort + " outPort: " + actionOutputPort);
 		
-		//
-		// 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.
-		//
-		
-		return add(sw,fm);
+		return add(sw, fm);
 	}
 	
 	@Override
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 c357e7c..7d5527b 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowSynchronizer.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowSynchronizer.java
@@ -246,7 +246,7 @@
 		return;
 	    }
 
-	    pusher.add(sw, flowEntry);
+	    pusher.pushFlowEntry(sw, flowEntry);
 	}
 	
 	/**
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 2f550a7..6bf20d9 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/IFlowPusherService.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/IFlowPusherService.java
@@ -1,5 +1,7 @@
 package net.onrc.onos.ofcontroller.flowprogrammer;
 
+import java.util.Collection;
+
 import org.openflow.protocol.OFBarrierReply;
 import org.openflow.protocol.OFMessage;
 
@@ -7,6 +9,7 @@
 import net.floodlightcontroller.core.internal.OFMessageFuture;
 import net.floodlightcontroller.core.module.IFloodlightService;
 import net.onrc.onos.ofcontroller.util.FlowEntry;
+import net.onrc.onos.ofcontroller.util.Pair;
 
 /**
  * FlowPusherService is a service to send message to switches in proper rate.
@@ -47,6 +50,9 @@
 	
 	/**
 	 * Add a message to the queue of the switch.
+	 *
+	 * Note: Notification is NOT delivered for the pushed message.
+	 *
 	 * @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.
@@ -54,12 +60,28 @@
 	boolean add(IOFSwitch sw, OFMessage msg);
 
 	/**
-	 * Create a message from FlowEntry and add it to the queue of the switch.
+	 * Push a collection of Flow Entries to the corresponding switches.
+	 *
+	 * Note: Notification is delivered for the Flow Entries that
+	 * are pushed successfully.
+	 *
+	 * @param entries the collection of <IOFSwitch, FlowEntry> pairs
+	 * to push.
+	 */
+	void pushFlowEntries(Collection<Pair<IOFSwitch, FlowEntry>> entries);
+
+	/**
+	 * Create a message from FlowEntry and add it to the queue of the
+	 * switch.
+	 *
+	 * Note: Notification is delivered for the Flow Entries that
+	 * are pushed successfully.
+	 *
 	 * @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);
+	void pushFlowEntry(IOFSwitch sw, FlowEntry flowEntry);
 
 	/**
 	 * Set sending rate to a switch.
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/DoInterruptResource.java b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/DoInterruptResource.java
new file mode 100644
index 0000000..3c2920d
--- /dev/null
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/DoInterruptResource.java
@@ -0,0 +1,44 @@
+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: Interrupt synchronization to a switch.
+ *
+ *   GET /wm/fprog/synchronizer/interrupt/{dpid}/json"
+ */
+public class DoInterruptResource extends SynchronizerResource {
+
+    /**
+     * 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;
+    	}
+    	
+    	synchronizer.interrupt(sw);
+    	
+    	return true;
+    }
+}
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/DoSynchronizeResource.java b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/DoSynchronizeResource.java
new file mode 100644
index 0000000..dc8d431
--- /dev/null
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/DoSynchronizeResource.java
@@ -0,0 +1,44 @@
+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: Begin synchronization to a switch.
+ *
+ *   GET /wm/fprog/synchronizer/sync/{dpid}/json"
+ */
+public class DoSynchronizeResource extends SynchronizerResource {
+    /**
+     * 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;
+    	}
+    	
+    	synchronizer.synchronize(sw);
+    	
+    	return true;
+    }
+
+}
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
index 00d7fc9..22450f7 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/FlowProgrammerWebRoutable.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/FlowProgrammerWebRoutable.java
@@ -15,6 +15,8 @@
 		router.attach("/pusher/suspend/{dpid}/json", SuspendPusherResource.class);
 		router.attach("/pusher/resume/{dpid}/json", ResumePusherResource.class);
 		router.attach("/pusher/barrier/{dpid}/json", SendBarrierResource.class);
+		router.attach("/synchronizer/sync/{dpid}/json", DoSynchronizeResource.class);
+		router.attach("/synchronizer/interrupt/{dpid}/json", DoInterruptResource.class);
 		return router;
 	}
 
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/SynchronizerResource.java b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/SynchronizerResource.java
new file mode 100644
index 0000000..12bf8f3
--- /dev/null
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowprogrammer/web/SynchronizerResource.java
@@ -0,0 +1,35 @@
+package net.onrc.onos.ofcontroller.flowprogrammer.web;
+
+import net.floodlightcontroller.core.IFloodlightProviderService;
+import net.onrc.onos.ofcontroller.flowprogrammer.IFlowSyncService;
+
+import org.restlet.resource.ServerResource;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class SynchronizerResource extends ServerResource {
+    protected final static Logger log = LoggerFactory.getLogger(SynchronizerResource.class);
+    
+    protected IFloodlightProviderService provider;
+    protected IFlowSyncService synchronizer;
+
+    protected boolean init() {
+    	provider = (IFloodlightProviderService)
+    			getContext().getAttributes().
+    			get(IFloodlightProviderService.class.getCanonicalName());
+    	if (provider == null) {
+		    log.debug("ONOS FloodlightProvider not found");
+		    return false;
+		}
+    	
+    	synchronizer = (IFlowSyncService)
+    			getContext().getAttributes().
+    			get(IFlowSyncService.class.getCanonicalName());
+    	if (synchronizer == null) {
+		    log.debug("ONOS FlowSyncService not found");
+		    return false;
+		}
+    	
+    	return true;
+    }
+}
diff --git a/src/main/java/net/onrc/onos/ofcontroller/forwarding/Forwarding.java b/src/main/java/net/onrc/onos/ofcontroller/forwarding/Forwarding.java
index ea6e384..b6dffd8 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/forwarding/Forwarding.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/forwarding/Forwarding.java
@@ -186,10 +186,11 @@
 		
 		CallerId callerId = new CallerId("Forwarding");
 		
-		FlowId flowId = new FlowId(flowService.getNextFlowEntryId());
+		//FlowId flowId = new FlowId(flowService.getNextFlowEntryId());
 		FlowPath flowPath = new FlowPath();
-		flowPath.setFlowId(flowId);
+		//flowPath.setFlowId(flowId);
 		flowPath.setInstallerId(callerId);
+
 		flowPath.setFlowPathType(FlowPathType.FP_TYPE_SHORTEST_PATH);
 		flowPath.setFlowPathUserState(FlowPathUserState.FP_USER_ADD);
 		flowPath.setFlowEntryMatch(new FlowEntryMatch());
@@ -199,8 +200,9 @@
 		// forwarding other stuff like ARP.
 		flowPath.flowEntryMatch().enableEthernetFrameType(Ethernet.TYPE_IPv4);
 		flowPath.setDataPath(dataPath);
-		
-		flowService.addFlow(flowPath, flowId);
+			
+		FlowId flowId = flowService.addFlow(flowPath);
+		//flowService.addFlow(flowPath, flowId);
 		
 		
 		DataPath reverseDataPath = new DataPath();
@@ -208,10 +210,10 @@
 		reverseDataPath.setSrcPort(dstSwitchPort);
 		reverseDataPath.setDstPort(srcSwitchPort);
 		
-		FlowId reverseFlowId = new FlowId(flowService.getNextFlowEntryId());
+		//FlowId reverseFlowId = new FlowId(flowService.getNextFlowEntryId());
 		// TODO implement copy constructor for FlowPath
 		FlowPath reverseFlowPath = new FlowPath();
-		reverseFlowPath.setFlowId(reverseFlowId);
+		//reverseFlowPath.setFlowId(reverseFlowId);
 		reverseFlowPath.setInstallerId(callerId);
 		reverseFlowPath.setFlowPathType(FlowPathType.FP_TYPE_SHORTEST_PATH);
 		reverseFlowPath.setFlowPathUserState(FlowPathUserState.FP_USER_ADD);
@@ -224,9 +226,9 @@
 		reverseFlowPath.dataPath().srcPort().dpid().toString();
 		
 		// TODO what happens if no path exists?
-		flowService.addFlow(reverseFlowPath, reverseFlowId);
+		//flowService.addFlow(reverseFlowPath, reverseFlowId);
+		FlowId reverseFlowId = flowService.addFlow(reverseFlowPath);
 		
-
 		Port outPort = shortestPath.flowEntries().get(0).outPort();
 		forwardPacket(pi, sw, outPort.value());
 	}
diff --git a/src/main/java/net/onrc/onos/ofcontroller/util/Pair.java b/src/main/java/net/onrc/onos/ofcontroller/util/Pair.java
new file mode 100644
index 0000000..2245758
--- /dev/null
+++ b/src/main/java/net/onrc/onos/ofcontroller/util/Pair.java
@@ -0,0 +1,20 @@
+package net.onrc.onos.ofcontroller.util;
+
+/**
+ * A generic class representing a pair of two values.
+ */
+public class Pair<F, S> {
+    public F first;		// The first value in the pair
+    public S second;		// The second value in the pair
+
+    /**
+     * Constructor for a pair of two values.
+     *
+     * @param first the first value in the pair.
+     * @param second the second value in the pair.
+     */
+    public Pair(F first, S second) {
+	this.first = first;
+	this.second = second;
+    }
+}
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 8a727d3..c54e89d 100644
--- a/src/test/java/net/onrc/onos/ofcontroller/flowmanager/FlowManagerTest.java
+++ b/src/test/java/net/onrc/onos/ofcontroller/flowmanager/FlowManagerTest.java
@@ -142,7 +142,7 @@
 
 
 	/**
-	 * Test method for {@link FlowManager#addFlow(FlowPath, FlowId, String)}.
+	 * Test method for {@link FlowManager#addFlow(FlowPath)}.
 	 * @throws Exception 
 	 */
 	@Test
@@ -163,15 +163,15 @@
 		replayAll();
 
 		fm.init(context);
-		Boolean result = fm.addFlow(flowPath, flowId);
+		FlowId result = fm.addFlow(flowPath);
 
 		// verify the test
 		verifyAll();
-		assertFalse(result);
+		assertNotNull(result);
 	}
 
 	/**
-	 * Test method for {@link FlowManager#addFlow(FlowPath, FlowId)}.
+	 * Test method for {@link FlowManager#addFlow(FlowPath)}.
 	 * @throws Exception 
 	 */
 	@Test
@@ -233,11 +233,11 @@
 		replayAll();
 		
 		fm.init(context);
-		Boolean result = fm.addFlow(flowPath, new FlowId(0x100));
+		FlowId result = fm.addFlow(flowPath);
 
 		// verify the test
 		verifyAll();
-		assertTrue(result);
+		assertNotNull(result);
 	}
 
 	/**
@@ -388,76 +388,6 @@
 	}
 	
 	/**
-	 * Test method for {@link FlowManager#getAllFlows(CallerId, DataPathEndpoints)}.
-	 * @throws Exception 
-	 */ 
-	@Test
-	public final void testGetAllFlowsWithCallerIdAndDataPathEndpointsSuccessNormally() throws Exception {
-		final String getAllFlows = "getAllFlows";
-		// create mock objects
-		FlowManager fm = createPartialMock(FlowManager.class, getAllFlows,
-				new Class<?>[]{}, new Object[]{});
-
-		// instantiate required objects
-		DataPathEndpoints dataPathEndpoints = new DataPathEndpoints(
-				new SwitchPort(new Dpid(1), new Port((short)1)),
-				new SwitchPort(new Dpid(2), new Port((short)2)));
-
-		ArrayList<FlowPath> obtainedAllFlows = createTestFlowPaths();
-			
-		//setup expectations
-		expectInitWithContext();
-		expectPrivate(fm, getAllFlows).andReturn(obtainedAllFlows);
-		
-		//start the test
-		replayAll();
-		
-		fm.init(context);
-		ArrayList<FlowPath> flows = fm.getAllFlows(new CallerId("caller id"), dataPathEndpoints);
-
-		// verify the test
-		verifyAll();
-		assertEquals(1, flows.size());
-		assertEquals(obtainedAllFlows.get(1), flows.get(0));
-	}
-	
-	/**
-	 * Test method for {@link FlowManager#getAllFlows(DataPathEndpoints)}.
-	 * @throws Exception 
-	 */
-	@Test
-	public final void testGetAllFlowsWithDataPathEndpointsSuccessNormally() throws Exception {
-		final String getAllFlows = "getAllFlows";
-		// create mock objects
-		FlowManager fm = createPartialMock(FlowManager.class, getAllFlows,
-				new Class<?>[]{}, new Object[]{});
-
-		// instantiate required objects
-		DataPathEndpoints dataPathEndpoints = new DataPathEndpoints(
-				new SwitchPort(new Dpid(1), new Port((short)1)),
-				new SwitchPort(new Dpid(2), new Port((short)2)));
-
-		ArrayList<FlowPath> obtainedAllFlows = createTestFlowPaths();
-			
-		//setup expectations
-		expectInitWithContext();
-		expectPrivate(fm, getAllFlows).andReturn(obtainedAllFlows);
-		
-		//start the test
-		replayAll();
-		
-		fm.init(context);
-		ArrayList<FlowPath> flows = fm.getAllFlows(dataPathEndpoints);
-
-		// verify the test
-		verifyAll();
-		assertEquals(2, flows.size());
-		assertEquals(obtainedAllFlows.get(0), flows.get(0));
-		assertEquals(obtainedAllFlows.get(1), flows.get(1));
-		// TODO: ignore the order of flows in the list
-	}
-	
-	/**
 	 * Test method for {@link FlowManager#getAllFlowsSummary(FlowId, int)}.
 	 * @throws Exception 
 	 */
@@ -533,72 +463,6 @@
 		// TODO: more asserts
 		// TODO: ignore seq. of the list
 	}
-	
-	/**
-	 * Test method for {@link FlowManager#addAndMaintainShortestPathFlow(FlowPath)}.
-	 * @throws Exception 
-	 */
-	@Test
-	public final void testAddAndMaintainShortestPathFlowSuccessNormally() throws Exception {
-		final String addFlow = "addFlow";
-
-		// create mock objects
-		FlowManager fm = createPartialMockAndInvokeDefaultConstructor(FlowManager.class, addFlow);
-
-		// instantiate required objects
-		DataPath dataPath = new DataPath();
-		dataPath.setSrcPort(new SwitchPort(new Dpid(1), new Port((short)3)));
-		dataPath.setDstPort(new SwitchPort(new Dpid(2), new Port((short)4)));
-		FlowEntryMatch match = new FlowEntryMatch();
-		FlowPath paramFlow = new FlowPath();
-		paramFlow.setFlowId(new FlowId(100));
-		paramFlow.setInstallerId(new CallerId("installer id"));
-		paramFlow.setFlowPathType(FlowPathType.valueOf("FP_TYPE_SHORTEST_PATH"));
-		paramFlow.setFlowPathUserState(FlowPathUserState.valueOf("FP_USER_ADD"));
-		paramFlow.setFlowPathFlags(new FlowPathFlags(0));
-		paramFlow.setDataPath(dataPath);
-		paramFlow.setFlowEntryMatch(match);
-		
-		// setup expectations
-		expectInitWithContext();
-		expectPrivate(fm, addFlow,
-				EasyMock.anyObject(FlowPath.class),
-				EasyMock.anyObject(FlowId.class),
-				EasyMock.anyObject(String.class)
-				).andAnswer(new IAnswer<Object>() {
-					public Object answer() throws Exception {
-						FlowPath flowPath = (FlowPath)EasyMock.getCurrentArguments()[0];
-						assertEquals(flowPath.flowId().value(), 100);
-						assertEquals(flowPath.installerId().toString(), "installer id");
-						assertEquals(flowPath.flowPathType().toString(), "PF_TYPE_SHORTEST_PATH");
-						assertEquals(flowPath.flowPathUserState().toString(), "PF_USER_STATE");
-						assertEquals(flowPath.flowPathFlags().flags(), 0);
-						assertEquals(flowPath.dataPath().srcPort().toString(),
-								new SwitchPort(new Dpid(1), new Port((short)3)).toString());
-
-						String dataPathSummary = (String)EasyMock.getCurrentArguments()[2];
-						assertEquals(dataPathSummary, "X");
-						
-						return true;
-					}
-				});
-		
-		// start the test
-		replayAll();
-
-		fm.init(context);
-		FlowPath resultFlow = fm.addAndMaintainShortestPathFlow(paramFlow);
-				
-		// verify the test
-		verifyAll();
-		assertEquals(paramFlow.flowId().value(), resultFlow.flowId().value());
-		assertEquals(paramFlow.installerId().toString(), resultFlow.installerId().toString());
-		assertEquals(paramFlow.flowPathType().toString(), resultFlow.flowPathType().toString());
-		assertEquals(paramFlow.flowPathUserState().toString(), resultFlow.flowPathUserState().toString());
-		assertEquals(paramFlow.flowPathFlags().flags(), resultFlow.flowPathFlags().flags());
-		assertEquals(paramFlow.dataPath().toString(), resultFlow.dataPath().toString());
-		assertEquals(paramFlow.flowEntryMatch().toString(), resultFlow.flowEntryMatch().toString());
-	}
 		
 	// INetMapStorage methods
 	
diff --git a/src/test/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowPusherTest.java b/src/test/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowPusherTest.java
index 4c66367..4779b75 100644
--- a/src/test/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowPusherTest.java
+++ b/src/test/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowPusherTest.java
@@ -1,10 +1,10 @@
 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.Collection;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -17,29 +17,19 @@
 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.flowmanager.IFlowService;
 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;
@@ -55,8 +45,9 @@
 	private FloodlightModuleContext modContext;
 	private BasicFactory factory;
 	private OFMessageDamper damper;
-	private IFloodlightProviderService flservice;
-	private IThreadPoolService tpservice;
+	private IFloodlightProviderService flProviderService;
+	private IThreadPoolService threadPoolService;
+	private IFlowService flowService;
 
 	/**
 	 * Test single OFMessage is correctly sent to single switch via MessageDamper.
@@ -77,7 +68,8 @@
 		EasyMock.replay(sw);
 		
 		try {
-			EasyMock.expect(damper.write(EasyMock.eq(sw), EasyMock.eq(msg), EasyMock.eq(context))).andReturn(true).once();
+			EasyMock.expect(damper.write(EasyMock.eq(sw), EasyMock.eq(msg), EasyMock.eq(context)))
+				.andReturn(true).once();
 		} catch (IOException e1) {
 			fail("Failed in OFMessageDamper#write()");
 		}
@@ -451,7 +443,7 @@
 		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(threadPoolService.getScheduledExecutor()).andReturn(executor);
 
 		IOFSwitch sw = EasyMock.createMock(IOFSwitch.class);
 		EasyMock.expect(sw.getId()).andReturn((long)1).anyTimes();
@@ -477,7 +469,7 @@
 		endInitMock();
 		initPusher(1);
 
-		pusher.add(sw, flowEntry1);
+		pusher.pushFlowEntry(sw, flowEntry1);
 		
 		try {
 			Thread.sleep(1000);
@@ -490,26 +482,34 @@
 		pusher.stop();
 	}
 	
+	@SuppressWarnings("unchecked")
 	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);
+		flProviderService = EasyMock.createMock(IFloodlightProviderService.class);
+		threadPoolService = EasyMock.createMock(IThreadPoolService.class);
+		flowService = EasyMock.createMock(IFlowService.class);
+		
+		flowService.flowEntriesPushedToSwitch(EasyMock.anyObject(Collection.class));
+		EasyMock.expectLastCall().anyTimes();
 		
 		EasyMock.expect(modContext.getServiceImpl(EasyMock.eq(IThreadPoolService.class)))
-			.andReturn(tpservice).once();
+			.andReturn(threadPoolService).once();
 		EasyMock.expect(modContext.getServiceImpl(EasyMock.eq(IFloodlightProviderService.class)))
-			.andReturn(flservice).once();
-		flservice.addOFMessageListener(EasyMock.eq(OFType.BARRIER_REPLY),
+			.andReturn(flProviderService).once();
+		EasyMock.expect(modContext.getServiceImpl(EasyMock.eq(IFlowService.class)))
+			.andReturn(flowService).once();
+		flProviderService.addOFMessageListener(EasyMock.eq(OFType.BARRIER_REPLY),
 				(FlowPusher) EasyMock.anyObject());
 		EasyMock.expectLastCall().once();
 	}
 	
 	private void endInitMock() {
-		EasyMock.replay(tpservice);
-		EasyMock.replay(flservice);
+		EasyMock.replay(flowService);
+		EasyMock.replay(threadPoolService);
+		EasyMock.replay(flProviderService);
 		EasyMock.replay(damper);
 		EasyMock.replay(factory);
 		EasyMock.replay(modContext);
@@ -536,27 +536,9 @@
 		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(threadPoolService.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/src/test/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowSynchronizerTest.java b/src/test/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowSynchronizerTest.java
new file mode 100644
index 0000000..5b1bbdd
--- /dev/null
+++ b/src/test/java/net/onrc/onos/ofcontroller/flowprogrammer/FlowSynchronizerTest.java
@@ -0,0 +1,313 @@
+package net.onrc.onos.ofcontroller.flowprogrammer;
+
+import static org.junit.Assert.*;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.ExecutionException;
+
+import io.netty.util.concurrent.Future;
+import net.floodlightcontroller.core.IOFSwitch;
+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.flowmanager.FlowDatabaseOperation;
+import net.onrc.onos.ofcontroller.util.FlowEntry;
+import net.onrc.onos.ofcontroller.util.FlowEntryId;
+
+import org.easymock.EasyMock;
+import org.easymock.IAnswer;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.openflow.protocol.OFFlowMod;
+import org.openflow.protocol.OFMatch;
+import org.openflow.protocol.OFMessage;
+import org.openflow.protocol.OFStatisticsRequest;
+import org.openflow.protocol.OFType;
+import org.openflow.protocol.statistics.OFFlowStatisticsReply;
+import org.openflow.protocol.statistics.OFStatistics;
+import org.powermock.api.easymock.PowerMock;
+import org.powermock.core.classloader.annotations.PrepareForTest;
+import org.powermock.modules.junit4.PowerMockRunner;
+
+
+@RunWith(PowerMockRunner.class)
+@PrepareForTest({FlowSynchronizer.class, GraphDBOperation.class, FlowDatabaseOperation.class})
+public class FlowSynchronizerTest {
+	private FlowPusher pusher;
+	private FlowSynchronizer sync;
+	private List<Long> idAdded;
+	private List<Long> idRemoved;
+
+	@Before
+	public void setUp() throws Exception {
+		idAdded = new ArrayList<Long>();
+		idRemoved = new ArrayList<Long>();
+		
+		pusher = EasyMock.createMock(FlowPusher.class);
+		pusher.add(EasyMock.anyObject(IOFSwitch.class), EasyMock.anyObject(OFMessage.class));
+		EasyMock.expectLastCall().andAnswer(new IAnswer<Object>() {
+				@Override
+				public Object answer() throws Throwable {
+					OFMessage msg = (OFMessage)EasyMock.getCurrentArguments()[1];
+					if (msg.getType().equals(OFType.FLOW_MOD)) {
+						OFFlowMod fm = (OFFlowMod)msg;
+						if (fm.getCommand() == OFFlowMod.OFPFC_DELETE_STRICT) {
+							idRemoved.add(fm.getCookie());
+						}
+					}
+					return null;
+				}
+			}).anyTimes();
+		pusher.pushFlowEntry(EasyMock.anyObject(IOFSwitch.class), EasyMock.anyObject(FlowEntry.class));
+		EasyMock.expectLastCall().andAnswer(new IAnswer<Object>() {
+			@Override
+			public Object answer() throws Throwable {
+				FlowEntry flow = (FlowEntry)EasyMock.getCurrentArguments()[1];
+				idAdded.add(flow.flowEntryId().value());
+				return null;
+			}
+		}).anyTimes();
+		EasyMock.replay(pusher);
+	}
+
+	@After
+	public void tearDown() throws Exception {
+	}
+
+	/**
+	 * Test that synchronization doesn't affect anything in case either DB and
+	 * flow table has the same entries.
+	 */
+	@Test
+	public void testStable() {
+		// Create mock of flow table : flow 1
+		IOFSwitch sw = createMockSwitch(new long[] {1});
+		
+		// Create mock of flow entries : flow 1
+		initMockGraph(new long[] {1});
+		
+		// synchronize
+		doSynchronization(sw,100);
+		
+		// check if flow is not changed
+		assertEquals(0, idAdded.size());
+		assertEquals(0, idRemoved.size());
+	}
+
+	/**
+	 * Test that an flow is added in case DB has an extra FlowEntry.
+	 */
+	@Test
+	public void testSingleAdd() {
+		// Create mock of flow table : null
+		IOFSwitch sw = createMockSwitch(new long[] {});
+		
+		// Create mock of flow entries : flow 1
+		initMockGraph(new long[] {1});
+		
+		// synchronize
+		doSynchronization(sw,100);
+		
+		// check if single flow is installed
+		assertEquals(1, idAdded.size());
+		assertTrue(idAdded.contains((long)1));
+		assertEquals(0, idRemoved.size());
+	}
+
+	/**
+	 * Test that an flow is deleted in case switch has an extra FlowEntry.
+	 */
+	@Test
+	public void testSingleDelete() {
+		// Create mock of flow table : flow 1
+		IOFSwitch sw = createMockSwitch(new long[] {1});
+		
+		// Create mock of flow entries : null
+		initMockGraph(new long[] {});
+		
+		// synchronize
+		doSynchronization(sw,100);
+		
+		// check if single flow is deleted
+		assertEquals(0, idAdded.size());
+		assertEquals(1, idRemoved.size());
+		assertTrue(idRemoved.contains((long)1));
+	}
+	
+	/**
+	 * Test that appropriate flows are added and other appropriate flows are deleted
+	 * in case flows in DB are overlapping flows in switch.
+	 */
+	@Test
+	public void testMixed() {
+		// Create mock of flow table : flow 1,2,3
+		IOFSwitch sw = createMockSwitch(new long[] {1,2,3});
+		
+		// Create mock of flow entries : flow 2,3,4,5
+		initMockGraph(new long[] {2,3,4,5});
+		
+		// synchronize
+		doSynchronization(sw,100);
+		
+		// check if two flows {4,5} is installed and one flow {1} is deleted
+		assertEquals(2, idAdded.size());
+		assertTrue(idAdded.contains((long)4));
+		assertTrue(idAdded.contains((long)5));
+		assertEquals(1, idRemoved.size());
+		assertTrue(idRemoved.contains((long)1));
+	}
+	
+
+	@Test
+	public void testMassive() {
+		// Create mock of flow table : flow 0-1999
+		long [] swIdList = new long [2000];
+		for (long i = 0; i < 2000; ++i) {
+			swIdList[(int)i] = i;
+		}
+		IOFSwitch sw = createMockSwitch(swIdList);
+		
+		// Create mock of flow entries : flow 1500-3499
+		long [] dbIdList = new long [2000];
+		for (long i = 0; i < 2000; ++i) {
+			dbIdList[(int)i] = 1500 + i;
+		}
+		initMockGraph(dbIdList);
+
+		// synchronize
+		doSynchronization(sw, 3000);
+		
+		// check if 1500 flows {2000-3499} is installed and 1500 flows {0,...,1499} is deleted
+		assertEquals(1500, idAdded.size());
+		for (long i = 2000; i < 3500; ++i) {
+			assertTrue(idAdded.contains(i));
+		}
+		assertEquals(1500, idRemoved.size());
+		for (long i = 0; i < 1500; ++i) {
+			assertTrue(idRemoved.contains(i));
+		}
+	}
+
+	/**
+	 * Create mock IOFSwitch with flow table which has arbitrary flows.
+	 * @param cookieList List of FlowEntry IDs switch has.
+	 * @return Mock object.
+	 */
+	private IOFSwitch createMockSwitch(long[] cookieList) {
+		IOFSwitch sw = EasyMock.createMock(IOFSwitch.class);
+		EasyMock.expect(sw.getId()).andReturn((long)1).anyTimes();
+		
+		List<OFStatistics> stats = new ArrayList<OFStatistics>();
+		for (long cookie : cookieList) {
+			stats.add(createReply(cookie));
+		}
+		
+		@SuppressWarnings("unchecked")
+		Future<List<OFStatistics>> future = EasyMock.createMock(Future.class);
+		try {
+			EasyMock.expect(future.get()).andReturn(stats).once();
+		} catch (InterruptedException e1) {
+			fail("Failed in Future#get()");
+		} catch (ExecutionException e1) {
+			fail("Failed in Future#get()");
+		}
+		EasyMock.replay(future);
+		
+		try {
+			EasyMock.expect(sw.getStatistics(EasyMock.anyObject(OFStatisticsRequest.class)))
+				.andReturn(future).once();
+		} catch (IOException e) {
+			fail("Failed in IOFSwitch#getStatistics()");
+		}
+		
+		EasyMock.replay(sw);
+		return sw;
+	}
+	
+	/**
+	 * Create single OFFlowStatisticsReply object which is actually obtained from switch.
+	 * @param cookie Cookie value, which indicates ID of FlowEntry installed to switch.
+	 * @return Created object.
+	 */
+	private OFFlowStatisticsReply createReply(long cookie) {
+		OFFlowStatisticsReply stat = new OFFlowStatisticsReply();
+		OFMatch match = new OFMatch();
+		
+		stat.setCookie(cookie);
+		stat.setMatch(match);
+		stat.setPriority((short)1);
+
+		return stat;
+	}
+	
+	/**
+	 * Create mock GraphDBOperation and FlowDatabaseOperation to mock DB.
+	 * @param idList List of FlowEntry IDs stored in DB.
+	 */
+	private void initMockGraph(long[] idList) {
+		List<IFlowEntry> flowEntryList = new ArrayList<IFlowEntry>();
+		
+		for (long id : idList) {
+			IFlowEntry entry = EasyMock.createMock(IFlowEntry.class);
+			EasyMock.expect(entry.getFlowEntryId()).andReturn(String.valueOf(id)).anyTimes();
+			EasyMock.replay(entry);
+			flowEntryList.add(entry);
+		}
+		
+		ISwitchObject swObj = EasyMock.createMock(ISwitchObject.class);
+		EasyMock.expect(swObj.getFlowEntries()).andReturn(flowEntryList).once();
+		EasyMock.replay(swObj);
+		
+		GraphDBOperation mockOp = PowerMock.createMock(GraphDBOperation.class);
+		EasyMock.expect(mockOp.searchSwitch(EasyMock.anyObject(String.class))).andReturn(swObj).once();
+		
+		PowerMock.mockStatic(FlowDatabaseOperation.class);
+		for (IFlowEntry entry : flowEntryList) {
+			EasyMock.expect(FlowDatabaseOperation.extractFlowEntry(EasyMock.eq(entry)))
+				.andAnswer(new IAnswer<FlowEntry>() {
+					@Override
+					public FlowEntry answer() throws Throwable {
+						IFlowEntry iflow = (IFlowEntry)EasyMock.getCurrentArguments()[0];
+						long flowEntryId = Long.valueOf(iflow.getFlowEntryId());
+						
+						FlowEntry flow = EasyMock.createMock(FlowEntry.class);
+						EasyMock.expect(flow.flowEntryId()).andReturn(new FlowEntryId(flowEntryId)).anyTimes();
+						EasyMock.replay(flow);
+						return flow;
+					}
+					
+				}).anyTimes();
+			EasyMock.expect(mockOp.searchFlowEntry(EasyMock.eq(new FlowEntryId(entry.getFlowEntryId()))))
+				.andReturn(entry);
+		}
+		PowerMock.replay(FlowDatabaseOperation.class);
+		EasyMock.replay(mockOp);
+		
+		try {
+			PowerMock.expectNew(GraphDBOperation.class, "").andReturn(mockOp);
+		} catch (Exception e) {
+			fail("Failed to create GraphDBOperation");
+		}
+		PowerMock.replay(GraphDBOperation.class);
+	}
+	
+	/**
+	 * Instantiate FlowSynchronizer and sync flows.
+	 * @param sw Target IOFSwitch object
+	 */
+	private void doSynchronization(IOFSwitch sw, long wait) {
+		sync = new FlowSynchronizer();
+		sync.init(pusher);
+		sync.synchronize(sw);
+		
+		try {
+			Thread.sleep(wait);
+		} catch (InterruptedException e) {
+			fail("Failed to sleep");
+		}
+	}
+}
diff --git a/web/add_flow.py b/web/add_flow.py
index eed75f9..c621c30 100755
--- a/web/add_flow.py
+++ b/web/add_flow.py
@@ -488,6 +488,8 @@
 if __name__ == "__main__":
   usage_msg = "Usage: %s [Flags] <flow-id> <installer-id> <src-dpid> <src-port> <dest-dpid> <dest-port> [Flow Path Flags] [Match Conditions] [Actions]\n" % (sys.argv[0])
   usage_msg = usage_msg + "\n"
+  usage_msg = usage_msg + "    <flow-id>             The Flow ID, or -1 if it should be assigned by ONOS\n"
+  usage_msg = usage_msg + "\n"
   usage_msg = usage_msg + "    Flags:\n"
   usage_msg = usage_msg + "        -m [monitorname]  Monitor and maintain the installed shortest path(s)\n"
   usage_msg = usage_msg + "                          If 'monitorname' is specified and is set to 'ONOS'\n"
diff --git a/web/flowsync.py b/web/flowsync.py
new file mode 100755
index 0000000..51399d5
--- /dev/null
+++ b/web/flowsync.py
@@ -0,0 +1,103 @@
+#! /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/synchronizer/sync/<dpid>/json")
+# Sample output:
+#  "true"
+def synchronize(dpid):
+  try:
+    command = "curl -s \"http://%s:%s/wm/fprog/synchronizer/sync/%s/json\"" % (ControllerIP, ControllerPort, dpid)
+    debug("synchronize %s" % command)
+     
+    result = os.popen(command).read()
+    debug("result %s" % result)
+    if result == "false":
+      print "Failed to synchronize"
+      return;
+  except:
+    log_error("Controller IF has issue")
+    exit(1)
+  
+  print "Synchronization of switch %s has successfully began" % (dpid)
+
+# @app.route("/wm/fprog/synchronizer/interrupt/<dpid>/json")
+# Sample output:
+#  "true"
+def interrupt(dpid):
+  try:
+    command = "curl -s \"http://%s:%s/wm/fprog/synchronizer/interrupt/%s/json\"" % (ControllerIP, ControllerPort, dpid)
+    debug("interrupt %s" % command)
+     
+    result = os.popen(command).read()
+    debug("result %s" % result)
+    if result == "false":
+      print "Failed to interrupt synchronization"
+      return;
+  except:
+    log_error("Controller IF has issue")
+    exit(1)
+  
+  print "Synchronization of switch %s has successfully interrupted" % (dpid)
+
+
+if __name__ == "__main__":
+  usage_msg1 = "Usage:\n"
+  usage_msg2 = "%s sync <dpid>      : Start synchronization of the switch\n" % (sys.argv[0])
+  usage_msg3 = "                interrupt <dpid> : Interrupt synchronization of the switch\n"
+  usage_msg = usage_msg1 + usage_msg2 + usage_msg3;
+  
+  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] == "sync":
+    if len(sys.argv) < 3:
+      log_error(usage_msg)
+      exit(1)
+    synchronize(sys.argv[2])
+  elif sys.argv[1] == "interrupt":
+    if len(sys.argv) < 3:
+      log_error(usage_msg)
+      exit(1)
+    interrupt(sys.argv[2])
+  else:
+    log_error(usage_msg)
+    exit(1)
+ 
\ No newline at end of file
diff --git a/web/get_flow.py b/web/get_flow.py
index c45d853..72fbd4a 100755
--- a/web/get_flow.py
+++ b/web/get_flow.py
@@ -250,48 +250,6 @@
   print_flow_path(parsedResult)
 
 
-def get_installer_flow_paths(installer_id, v1, p1, v2, p2):
-  try:
-    command = "curl -s \"http://%s:%s/wm/flow/getall-by-installer-id/%s/%s/%s/%s/%s/json\"" % (ControllerIP, ControllerPort, installer_id, v1, p1, v2, p2)
-    debug("get_installer_flow_paths %s" % command)
-
-    result = os.popen(command).read()
-    debug("result %s" % result)
-    if len(result) == 0:
-	print "No Flows found"
-	return;
-
-    parsedResult = json.loads(result)
-    debug("parsed %s" % parsedResult)
-  except:
-    log_error("Controller IF has issue")
-    exit(1)
-
-  for flowPath in parsedResult:
-    print_flow_path(flowPath)
-
-
-def get_endpoints_flow_paths(v1, p1, v2, p2):
-  try:
-    command = "curl -s \"http://%s:%s/wm/flow/getall-by-endpoints/%s/%s/%s/%s/json\"" % (ControllerIP, ControllerPort, v1, p1, v2, p2)
-    debug("get_endpoints_flow_paths %s" % command)
-
-    result = os.popen(command).read()
-    debug("result %s" % result)
-    if len(result) == 0:
-	print "No Flows found"
-	return;
-
-    parsedResult = json.loads(result)
-    debug("parsed %s" % parsedResult)
-  except:
-    log_error("Controller IF has issue")
-    exit(1)
-
-  for flowPath in parsedResult:
-    print_flow_path(flowPath)
-
-
 def get_all_flow_paths():
   try:
     command = "curl -s \"http://%s:%s/wm/flow/getall/json\"" % (ControllerIP, ControllerPort)
@@ -316,9 +274,7 @@
   usage_msg1 = "Usage:\n"
   usage_msg2 = "%s <flow_id> : Print flow with Flow ID of <flow_id>\n" % (sys.argv[0])
   usage_msg3 = "                   all    : Print all flows\n"
-  usage_msg4 = "                   installer <installer-id> <src-dpid> <src-port> <dest-dpid> <dest-port>\n"
-  usage_msg5 = "                   endpoints <src-dpid> <src-port> <dest-dpid> <dest-port>"
-  usage_msg = usage_msg1 + usage_msg2 + usage_msg3 + usage_msg4 + usage_msg5;
+  usage_msg = usage_msg1 + usage_msg2 + usage_msg3;
 
   # app.debug = False;
 
@@ -335,17 +291,5 @@
   # Do the work
   if sys.argv[1] == "all":
     get_all_flow_paths()
-  elif sys.argv[1] == "installer":
-    if len(sys.argv) < 7:
-      log_error(usage_msg)
-      exit(1)
-    get_installer_flow_paths(sys.argv[2], sys.argv[3], sys.argv[4],
-			     sys.argv[5], sys.argv[6])
-  elif sys.argv[1] == "endpoints":
-    if len(sys.argv) < 6:
-      log_error(usage_msg)
-      exit(1)
-    get_endpoints_flow_paths(sys.argv[2], sys.argv[3], sys.argv[4],
-			     sys.argv[5])
   else:
     get_flow_path(sys.argv[1])