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 42f5e3c..a3f602f 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowManager.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowManager.java
@@ -18,7 +18,6 @@
 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.INetMapStorage;
@@ -31,13 +30,15 @@
 import net.onrc.onos.ofcontroller.topology.TopologyElement;
 import net.onrc.onos.ofcontroller.util.*;
 
+import org.openflow.protocol.OFMessage;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 /**
  * Flow Manager class for handling the network flows.
  */
-public class FlowManager implements IFloodlightModule, IFlowService, INetMapStorage {
+public class FlowManager implements IFloodlightModule, IFlowService, INetMapStorage,
+	IFlowPusherService {
 
     protected GraphDBOperation dbHandler;
 
@@ -106,6 +107,8 @@
 		Iterable<IFlowEntry> allFlowEntries =
 		    dbHandler.getAllSwitchNotUpdatedFlowEntries();
 		for (IFlowEntry flowEntryObj : allFlowEntries) {
+			log.debug("flowEntryobj : {}", flowEntryObj);
+			
 		    counterAllFlowEntries++;
 
 		    String dpidStr = flowEntryObj.getSwitchDpid();
@@ -140,6 +143,8 @@
 		    }
 		    counterMyNotUpdatedFlowEntries++;
 		}
+		
+		log.debug("addFlowEntries : {}", addFlowEntries);
 
 		//
 		// Process the Flow Entries that need to be added
@@ -443,12 +448,11 @@
 	
 	pusher = new FlowPusher();
 	pusher.init(null, floodlightProvider.getOFMessageFactory(), null);
+	
 	this.init("");
 
 	mapReaderScheduler = Executors.newScheduledThreadPool(1);
 	shortestPathReconcileScheduler = Executors.newScheduledThreadPool(1);
-	
-	pusher.start();
     }
 
     /**
@@ -486,6 +490,8 @@
 	// Initialize the Flow Entry ID generator
 	nextFlowEntryIdPrefix = randomGenerator.nextInt();
 
+	pusher.start();
+
 	//
 	// Create the Path Computation thread and register it with the
 	// Datagrid Service
@@ -779,7 +785,6 @@
      */
     private boolean installFlowEntry(IOFSwitch mySwitch, IFlowPath flowObj,
 				    IFlowEntry flowEntryObj) {
-    	log.debug("Flow is sent to pusher : dpid({}) flow_id({})", mySwitch.getId(), flowEntryObj.getFlowEntryId());
     	return pusher.send(mySwitch, flowObj, flowEntryObj);
     }
 
@@ -907,4 +912,44 @@
 
 	dbHandler.commit();
     }
+
+	@Override
+	public void addMessage(long dpid, OFMessage msg) {
+		IOFSwitch sw = floodlightProvider.getSwitches().get(dpid);
+		if (sw == null) {
+			return;
+		}
+		
+		pusher.send(sw, msg);
+	}
+
+	@Override
+	public boolean suspend(long dpid) {
+		IOFSwitch sw = floodlightProvider.getSwitches().get(dpid);
+		if (sw == null) {
+			return false;
+		}
+		
+		return pusher.suspend(sw);
+	}
+
+	@Override
+	public boolean resume(long dpid) {
+		IOFSwitch sw = floodlightProvider.getSwitches().get(dpid);
+		if (sw == null) {
+			return false;
+		}
+		
+		return pusher.resume(sw);
+	}
+
+	@Override
+	public boolean isSuspended(long dpid) {
+		IOFSwitch sw = floodlightProvider.getSwitches().get(dpid);
+		if (sw == null) {
+			return false;
+		}
+		
+		return pusher.isSuspended(sw);
+	}
 }
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowPusher.java b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowPusher.java
index 2511a3f..67d84e2 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowPusher.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowPusher.java
@@ -47,8 +47,6 @@
     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
-    
-    
 
 	public enum QueueState {
 		READY,
@@ -59,7 +57,7 @@
 		QueueState state;
 		
 		// Max rate of sending message (bytes/sec). 0 implies no limitation.
-		long max_rate = Long.MAX_VALUE;
+		long max_rate = 0;	// 0 indicates no limitation
 		long last_sent_time = 0;
 		long last_sent_size = 0;
 		
@@ -69,6 +67,11 @@
 		 * @return true if within the rate
 		 */
 		boolean isSendable(long current) {
+			if (max_rate == 0) {
+				// no limitation
+				return true;
+			}
+			
 			long rate = last_sent_size / (current - last_sent_time);
 			
 			if (rate < max_rate) {
@@ -122,14 +125,11 @@
 						continue;
 					}
 					
+					// check sending rate and determine it to be sent or not
+					long current_time = System.nanoTime();
+					
 					synchronized (queue) {
-						log.debug("Queue size : {}", queue.size());
-						
-						// check sending rate and determine it to be sent or not
-						long current_time = System.nanoTime();
-						
 						if (queue.isSendable(current_time)) {
-							// TODO send multiple messages at once
 							while (! queue.isEmpty()) {
 								OFMessage msg = queue.poll();
 								
@@ -159,6 +159,7 @@
 					} catch (InterruptedException e) {
 						// TODO Auto-generated catch block
 						e.printStackTrace();
+						log.error("Thread.sleep failed");
 					}
 				}
 				
@@ -168,6 +169,7 @@
 					log.debug("Pusher Process finished.");
 					return;
 				}
+
 			}
 		}
 	}
@@ -202,36 +204,51 @@
 	 * Suspend processing a queue related to given switch.
 	 * @param sw
 	 */
-	public void suspend(IOFSwitch sw) {
+	public boolean suspend(IOFSwitch sw) {
 		SwitchQueue queue = getQueue(sw);
 		
 		if (queue == null) {
-			return;
+			return false;
 		}
 		
 		synchronized (queue) {
 			if (queue.state == QueueState.READY) {
 				queue.state = QueueState.SUSPENDED;
+				return true;
 			}
+			return false;
 		}
 	}
 
 	/**
 	 * Resume processing a queue related to given switch.
 	 */
-	public void resume(IOFSwitch sw) {
+	public boolean resume(IOFSwitch sw) {
 		SwitchQueue queue = getQueue(sw);
 		
 		if (queue == null) {
-			return;
+			return false;
 		}
 		
 		synchronized (queue) {
 			if (queue.state == QueueState.SUSPENDED) {
 				queue.state = QueueState.READY;
+				return true;
 			}
+			return false;
 		}
 	}
+	
+	public boolean isSuspended(IOFSwitch sw) {
+		SwitchQueue queue = getQueue(sw);
+		
+		if (queue == null) {
+			// TODO Is true suitable for this case?
+			return true;
+		}
+		
+		return (queue.state == QueueState.SUSPENDED);
+	}
 
 	/**
 	 * End processing queue and exit thread.
@@ -268,6 +285,8 @@
 			}
 		}
 		
+		log.debug("Message is pushed : {}", msg);
+		
 		synchronized (queue) {
 			queue.add(msg);
 		}
@@ -285,6 +304,7 @@
 	 * @return
 	 */
 	public boolean send(IOFSwitch sw, IFlowPath flowObj, IFlowEntry flowEntryObj) {
+		log.debug("sending : {}, {}", sw, flowObj);
 		String flowEntryIdStr = flowEntryObj.getFlowEntryId();
 		if (flowEntryIdStr == null)
 		    return false;
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/IFlowPusherService.java b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/IFlowPusherService.java
new file mode 100644
index 0000000..830d47f
--- /dev/null
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/IFlowPusherService.java
@@ -0,0 +1,37 @@
+package net.onrc.onos.ofcontroller.flowmanager;
+
+import net.floodlightcontroller.core.IOFSwitch;
+import net.floodlightcontroller.core.module.IFloodlightService;
+
+import org.openflow.protocol.OFMessage;
+
+public interface IFlowPusherService extends IFloodlightService {
+	/**
+	 * Add a message to the queue of a switch.
+	 * @param sw
+	 * @param msg
+	 * @return
+	 */
+	void addMessage(long dpid, OFMessage msg);
+	
+	/**
+	 * Suspend pushing message to a switch.
+	 * @param sw
+	 * @return true if success
+	 */
+	boolean suspend(long dpid);
+	
+	/**
+	 * Resume pushing message to a switch.
+	 * @param sw
+	 * @return true if success
+	 */
+	boolean resume(long dpid);
+	
+	/**
+	 * Get whether pushing of message is suspended or not.
+	 * @param sw
+	 * @return true if suspended
+	 */
+	boolean isSuspended(long dpid);
+}