diff --git a/src/main/java/net/onrc/onos/datagrid/HazelcastDatagrid.java b/src/main/java/net/onrc/onos/datagrid/HazelcastDatagrid.java
index 9bd838b..e204e45 100755
--- a/src/main/java/net/onrc/onos/datagrid/HazelcastDatagrid.java
+++ b/src/main/java/net/onrc/onos/datagrid/HazelcastDatagrid.java
@@ -4,11 +4,7 @@
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
-import java.util.LinkedList;
-import java.util.List;
 import java.util.Map;
-import java.util.Set;
-import java.util.concurrent.TimeUnit;
 
 import net.floodlightcontroller.core.IFloodlightProviderService;
 import net.floodlightcontroller.core.module.FloodlightModuleContext;
@@ -17,30 +13,15 @@
 import net.floodlightcontroller.core.module.IFloodlightService;
 import net.floodlightcontroller.restserver.IRestApiService;
 import net.onrc.onos.datagrid.web.DatagridWebRoutable;
-import net.onrc.onos.ofcontroller.devicemanager.IDeviceEventHandler;
-import net.onrc.onos.ofcontroller.devicemanager.OnosDevice;
-import net.onrc.onos.ofcontroller.proxyarp.ArpReplyNotification;
-import net.onrc.onos.ofcontroller.proxyarp.IArpReplyEventHandler;
-import net.onrc.onos.ofcontroller.proxyarp.IPacketOutEventHandler;
-import net.onrc.onos.ofcontroller.proxyarp.PacketOutNotification;
-import net.onrc.onos.ofcontroller.util.serializers.KryoFactory;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import com.esotericsoftware.kryo.Kryo;
-import com.esotericsoftware.kryo.io.Input;
-import com.esotericsoftware.kryo.io.Output;
 import com.hazelcast.config.Config;
 import com.hazelcast.config.FileSystemXmlConfig;
-import com.hazelcast.core.EntryEvent;
-import com.hazelcast.core.EntryListener;
 import com.hazelcast.core.Hazelcast;
 import com.hazelcast.core.HazelcastInstance;
-import com.hazelcast.core.IList;
-import com.hazelcast.core.IMap;
 import com.hazelcast.instance.GroupProperties;
-import net.onrc.onos.intent.Intent;
 
 /**
  * A datagrid service that uses Hazelcast as a datagrid.
@@ -48,8 +29,6 @@
  * appropriate in a multi-node cluster.
  */
 public class HazelcastDatagrid implements IFloodlightModule, IDatagridService {
-    private static final int MAX_BUFFER_SIZE = 64 * 1024;
-
     static final Logger log = LoggerFactory.getLogger(HazelcastDatagrid.class);
     private IRestApiService restApi;
 
@@ -57,8 +36,6 @@
     private HazelcastInstance hazelcastInstance;
     private Config hazelcastConfig;
 
-    private final KryoFactory kryoFactory = new KryoFactory();
-
     //
     // NOTE: eventChannels is kept thread safe by using explicit "synchronized"
     // blocks below. Those are needed to protect the integrity of each entry
@@ -66,167 +43,13 @@
     //
     private final Map<String, IEventChannel<?, ?>> eventChannels = new HashMap<>();
 
-    // State related to the packet out map
-    private static final String PACKET_OUT_MAP_NAME = "packetOutMap";
-    private IMap<PacketOutNotification, byte[]> packetOutMap;
-    private final List<IPacketOutEventHandler> packetOutEventHandlers = new ArrayList<>();
-
-    private final byte[] dummyByte = {0};
-
-    // State related to the ARP reply map
-    private static final String ARP_REPLY_MAP_NAME = "arpReplyMap";
-    private IMap<ArpReplyNotification, byte[]> arpReplyMap;
-    private final List<IArpReplyEventHandler> arpReplyEventHandlers = new ArrayList<>();
-
-
-    private static final String INTENT_LIST_NAME = "intentList";
-    private IList<Intent> intentList;
-
-    @Override
-    public void registerIntent(Collection<Intent> intents) {
-        intentList.addAll(intents);
-    }
-
-
-    // State related to the Network Device map
-    private static final String MAP_DEVICE_NAME = "mapDevice";
-    private IMap<Long, OnosDevice> mapDevice;
-    private final List<IDeviceEventHandler> deviceEventHandlers = new ArrayList<>();
-
-    /**
-     * MapDeviceListener - reacts to Device related events.
-     */
-    class MapDeviceListener implements EntryListener<Long, OnosDevice> {
-
-        @Override
-        public void entryAdded(EntryEvent<Long, OnosDevice> event) {
-            for (IDeviceEventHandler deviceEventHandler : deviceEventHandlers) {
-                deviceEventHandler.addDeviceEvent(event.getKey(), event.getValue());
-            }
-        }
-
-        @Override
-        public void entryRemoved(EntryEvent<Long, OnosDevice> event) {
-            for (IDeviceEventHandler deviceEventHandler : deviceEventHandlers) {
-                deviceEventHandler.deleteDeviceEvent(event.getKey(), event.getValue());
-            }
-        }
-
-        @Override
-        public void entryUpdated(EntryEvent<Long, OnosDevice> event) {
-            for (IDeviceEventHandler deviceEventHandler : deviceEventHandlers) {
-                deviceEventHandler.updateDeviceEvent(event.getKey(), event.getValue());
-            }
-        }
-
-        @Override
-        public void entryEvicted(EntryEvent<Long, OnosDevice> arg0) {
-            //Not used.
-        }
-    }
-
-    /**
-     * Class for receiving notifications for sending packet-outs.
-     * <p/>
-     * The datagrid map is:
-     * - Key: Packet-out to send (PacketOutNotification)
-     * - Value: dummy value (we only need the key) (byte[])
-     */
-    class PacketOutMapListener implements EntryListener<PacketOutNotification, byte[]> {
-        /**
-         * Receive a notification that an entry is added.
-         *
-         * @param event the notification event for the entry.
-         */
-        @Override
-        public void entryAdded(EntryEvent<PacketOutNotification, byte[]> event) {
-            for (IPacketOutEventHandler packetOutEventHandler : packetOutEventHandlers) {
-                packetOutEventHandler.packetOutNotification(event.getKey());
-            }
-        }
-
-        /**
-         * Receive a notification that an entry is removed.
-         *
-         * @param event the notification event for the entry.
-         */
-        @Override
-        public void entryRemoved(EntryEvent<PacketOutNotification, byte[]> event) {
-            // Not used
-        }
-
-        /**
-         * Receive a notification that an entry is updated.
-         *
-         * @param event the notification event for the entry.
-         */
-        @Override
-        public void entryUpdated(EntryEvent<PacketOutNotification, byte[]> event) {
-            // Not used
-        }
-
-        /**
-         * Receive a notification that an entry is evicted.
-         *
-         * @param event the notification event for the entry.
-         */
-        @Override
-        public void entryEvicted(EntryEvent<PacketOutNotification, byte[]> event) {
-            // Not used
-        }
-    }
-
-    /**
-     * Class for receiving notifications for sending packet-outs.
-     * <p/>
-     * The datagrid map is:
-     * - Key: Packet-out to send (PacketOutNotification)
-     * - Value: dummy value (we only need the key) (byte[])
-     */
-    class ArpReplyMapListener implements EntryListener<ArpReplyNotification, byte[]> {
-        /**
-         * Receive a notification that an entry is added.
-         *
-         * @param event the notification event for the entry.
-         */
-        @Override
-        public void entryAdded(EntryEvent<ArpReplyNotification, byte[]> event) {
-            triggerEventHandler(event.getKey());
-        }
-
-        @Override
-        public void entryUpdated(EntryEvent<ArpReplyNotification, byte[]> event) {
-            triggerEventHandler(event.getKey());
-        }
-
-        @Override
-        public void entryRemoved(EntryEvent<ArpReplyNotification, byte[]> event) {
-            // Not used for ARP replies
-        }
-
-        @Override
-        public void entryEvicted(EntryEvent<ArpReplyNotification, byte[]> event) {
-            // Not used for ARP replies
-        }
-
-        /**
-         * Handle an event.
-         * @param notification notification
-         */
-        private void triggerEventHandler(ArpReplyNotification notification) {
-            for (IArpReplyEventHandler arpReplyEventHandler : arpReplyEventHandlers) {
-                arpReplyEventHandler.arpReplyEvent(notification);
-            }
-        }
-    }
-
     /**
      * Initialize the Hazelcast Datagrid operation.
      *
      * @param configFilename the configuration filename.
      */
     public void init(String configFilename) {
-    /*
+        /*
         System.setProperty("hazelcast.socket.receive.buffer.size", "32");
         System.setProperty("hazelcast.socket.send.buffer.size", "32");
         */
@@ -335,16 +158,6 @@
         hazelcastInstance = Hazelcast.newHazelcastInstance(hazelcastConfig);
 
         restApi.addRestletRoutable(new DatagridWebRoutable());
-
-        packetOutMap = hazelcastInstance.getMap(PACKET_OUT_MAP_NAME);
-        packetOutMap.addEntryListener(new PacketOutMapListener(), true);
-
-        arpReplyMap = hazelcastInstance.getMap(ARP_REPLY_MAP_NAME);
-        arpReplyMap.addEntryListener(new ArpReplyMapListener(), true);
-        intentList = hazelcastInstance.getList(INTENT_LIST_NAME);
-
-        mapDevice = hazelcastInstance.getMap(MAP_DEVICE_NAME);
-        mapDevice.addEntryListener(new MapDeviceListener(), true);
     }
 
     /**
@@ -469,65 +282,4 @@
             }
         }
     }
-
-    @Override
-    public void registerPacketOutEventHandler(IPacketOutEventHandler packetOutEventHandler) {
-        if (packetOutEventHandler != null) {
-            packetOutEventHandlers.add(packetOutEventHandler);
-        }
-    }
-
-    @Override
-    public void deregisterPacketOutEventHandler(IPacketOutEventHandler packetOutEventHandler) {
-        packetOutEventHandlers.remove(packetOutEventHandler);
-    }
-
-    @Override
-    public void registerArpReplyEventHandler(IArpReplyEventHandler arpReplyEventHandler) {
-        if (arpReplyEventHandler != null) {
-            arpReplyEventHandlers.add(arpReplyEventHandler);
-        }
-    }
-
-    @Override
-    public void deregisterArpReplyEventHandler(IArpReplyEventHandler arpReplyEventHandler) {
-        arpReplyEventHandlers.remove(arpReplyEventHandler);
-    }
-
-    @Override
-    public void registerMapDeviceEventHandler(IDeviceEventHandler deviceEventHandler) {
-        if (deviceEventHandler != null) {
-            deviceEventHandlers.add(deviceEventHandler);
-        }
-    }
-
-    @Override
-    public void deregisterMapDeviceEventHandler(IDeviceEventHandler deviceEventHandler) {
-        deviceEventHandlers.remove(deviceEventHandler);
-    }
-
-    @Override
-    public void sendPacketOutNotification(PacketOutNotification packetOutNotification) {
-        packetOutMap.putAsync(packetOutNotification, dummyByte, 1L, TimeUnit.MILLISECONDS);
-    }
-
-    @Override
-    public void sendArpReplyNotification(ArpReplyNotification arpReply) {
-        arpReplyMap.putAsync(arpReply, dummyByte, 1L, TimeUnit.MILLISECONDS);
-    }
-
-    @Override
-    public void sendNotificationDeviceAdded(Long mac, OnosDevice dev) {
-        log.debug("DeviceAdded in datagrid. mac {}", dev.getMacAddress());
-        mapDevice.putAsync(mac, dev);
-    }
-
-    @Override
-    public void sendNotificationDeviceDeleted(OnosDevice dev) {
-        long mac = dev.getMacAddress().toLong();
-        if (mapDevice.containsKey(mac)) {
-            log.debug("DeviceDeleted in datagrid. mac {}", dev.getMacAddress());
-            mapDevice.removeAsync(mac);
-        }
-    }
 }
diff --git a/src/main/java/net/onrc/onos/datagrid/IDatagridService.java b/src/main/java/net/onrc/onos/datagrid/IDatagridService.java
index 1045bcd..1015bf2 100755
--- a/src/main/java/net/onrc/onos/datagrid/IDatagridService.java
+++ b/src/main/java/net/onrc/onos/datagrid/IDatagridService.java
@@ -1,15 +1,6 @@
 package net.onrc.onos.datagrid;
 
-import java.util.Collection;
-
 import net.floodlightcontroller.core.module.IFloodlightService;
-import net.onrc.onos.intent.Intent;
-import net.onrc.onos.ofcontroller.devicemanager.IDeviceEventHandler;
-import net.onrc.onos.ofcontroller.devicemanager.OnosDevice;
-import net.onrc.onos.ofcontroller.proxyarp.ArpReplyNotification;
-import net.onrc.onos.ofcontroller.proxyarp.IArpReplyEventHandler;
-import net.onrc.onos.ofcontroller.proxyarp.IPacketOutEventHandler;
-import net.onrc.onos.ofcontroller.proxyarp.PacketOutNotification;
 
 /**
  * Interface for providing Datagrid Service to other modules.
@@ -53,65 +44,4 @@
      */
     <K, V> void removeListener(String channelName,
 			      IEventChannelListener<K, V> listener);
-
-    /*
-     * register all the intents as one batch
-     */
-    void registerIntent(Collection<Intent> intents);
-
-    /**
-     * Register event handler for packet-out events.
-     * 
-     * @param packetOutEventHandler The packet-out event handler to register.
-     */
-    public void registerPacketOutEventHandler(IPacketOutEventHandler packetOutEventHandler);
-    
-    /**
-     * Deregister event handler service for packet-out events.
-     * 
-     * @param packetOutEventHandler The packet-out event handler to deregister.
-     */
-    public void deregisterPacketOutEventHandler(IPacketOutEventHandler packetOutEventHandler);
-    
-    /**
-     * Register event handler for ARP reply events.
-     * 
-     * @param packetOutEventHandler The ARP reply event handler to register.
-     */
-    public void registerArpReplyEventHandler(IArpReplyEventHandler arpReplyEventHandler);
-    
-    /**
-     * Deregister event handler service for ARP reply events.
-     * 
-     * @param packetOutEventHandler The ARP reply event handler to deregister.
-     */
-    public void deregisterArpReplyEventHandler(IArpReplyEventHandler arpReplyEventHandler);
-
-    /**
-     * Send a packet-out notification to other ONOS instances. This informs
-     * other instances that they should send this packet out some of the ports
-     * they control. Not all notifications are applicable to all instances 
-     * (i.e. some notifications specify a single port to send the packet out),
-     * so each instance must determine whether it needs to take action when it
-     * receives the notification.
-     * 
-     * @param packetOutNotification The packet notification to send
-     */
-    public void sendPacketOutNotification(PacketOutNotification packetOutNotification);
-    
-    /**
-     * Send notification to other ONOS instances that an ARP reply has been 
-     * received.
-     * @param arpReply The notification of the ARP reply
-     */
-    public void sendArpReplyNotification(ArpReplyNotification arpReply);
-
-	void sendNotificationDeviceAdded(Long mac, OnosDevice dev);
-
-	void sendNotificationDeviceDeleted(OnosDevice dev);
-
-	void registerMapDeviceEventHandler(IDeviceEventHandler deviceEventHandler);
-
-	void deregisterMapDeviceEventHandler(IDeviceEventHandler deviceEventHandler);
-
 }
diff --git a/src/main/java/net/onrc/onos/ofcontroller/devicemanager/IDeviceEventHandler.java b/src/main/java/net/onrc/onos/ofcontroller/devicemanager/IDeviceEventHandler.java
deleted file mode 100644
index 81bc09f..0000000
--- a/src/main/java/net/onrc/onos/ofcontroller/devicemanager/IDeviceEventHandler.java
+++ /dev/null
@@ -1,7 +0,0 @@
-package net.onrc.onos.ofcontroller.devicemanager;
-
-public interface IDeviceEventHandler {
-	public void addDeviceEvent(Long key, OnosDevice value);
-	public void deleteDeviceEvent(Long key, OnosDevice value);
-	public void updateDeviceEvent(Long key, OnosDevice value);
-}
diff --git a/src/main/java/net/onrc/onos/ofcontroller/devicemanager/OnosDeviceManager.java b/src/main/java/net/onrc/onos/ofcontroller/devicemanager/OnosDeviceManager.java
index d6dffac..b7e9697 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/devicemanager/OnosDeviceManager.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/devicemanager/OnosDeviceManager.java
@@ -25,6 +25,8 @@
 import net.floodlightcontroller.core.module.IFloodlightService;
 import net.floodlightcontroller.util.MACAddress;
 import net.onrc.onos.datagrid.IDatagridService;
+import net.onrc.onos.datagrid.IEventChannel;
+import net.onrc.onos.datagrid.IEventChannelListener;
 import net.onrc.onos.packet.ARP;
 import net.onrc.onos.packet.DHCP;
 import net.onrc.onos.packet.Ethernet;
@@ -39,8 +41,10 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-public class OnosDeviceManager implements IFloodlightModule, IOFMessageListener,
-										IOnosDeviceService {
+public class OnosDeviceManager implements IFloodlightModule,
+					  IOFMessageListener,
+					  IOnosDeviceService,
+					  IEventChannelListener<Long, OnosDevice> {
 	protected final static Logger log = LoggerFactory.getLogger(OnosDeviceManager.class);
 	private static final int CLEANUP_SECOND = 60*60;
 	private static final int AGEING_MILLSEC = 60*60*1000;
@@ -50,6 +54,8 @@
 	private final static ScheduledExecutorService executor = Executors.newSingleThreadScheduledExecutor();
 
 	private IDatagridService datagrid;
+	private IEventChannel<Long, OnosDevice> eventChannel;
+	private static final String DEVICE_CHANNEL_NAME = "onos.device";
 	private Map<Long, OnosDevice> mapDevice = new ConcurrentHashMap<Long, OnosDevice>();
 	private INetworkGraphService networkGraphService;
 	private NetworkGraph networkGraph;
@@ -297,13 +303,16 @@
 	@Override
 	public void startUp(FloodlightModuleContext context) {
 		floodlightProvider.addOFMessageListener(OFType.PACKET_IN, this);
-		datagrid.registerMapDeviceEventHandler(new MapDevListener());
+		eventChannel = datagrid.addListener(DEVICE_CHANNEL_NAME, this,
+						    Long.class,
+						    OnosDevice.class);
 	}
 
     @Override
 	public void deleteOnosDevice(OnosDevice dev) {
-		datagrid.sendNotificationDeviceDeleted(dev);
-		floodlightProvider.publishUpdate(new OnosDeviceUpdate(dev, OnosDeviceUpdateType.DELETE));
+	    Long mac = dev.getMacAddress().toLong();
+	    eventChannel.removeEntry(mac);
+	    floodlightProvider.publishUpdate(new OnosDeviceUpdate(dev, OnosDeviceUpdateType.DELETE));
 	}
     
     @Override
@@ -314,31 +323,30 @@
 	
 	@Override
 	public void addOnosDevice(Long mac, OnosDevice dev) {
-        datagrid.sendNotificationDeviceAdded(mac, dev);
-        floodlightProvider.publishUpdate(new OnosDeviceUpdate(dev, OnosDeviceUpdateType.ADD));
+	    eventChannel.addEntry(mac, dev);
+	    floodlightProvider.publishUpdate(new OnosDeviceUpdate(dev, OnosDeviceUpdateType.ADD));
 	}
 
-	//This is listener for datagrid mapDevice change.
-    class MapDevListener implements IDeviceEventHandler {
+	@Override
+	public void entryAdded(OnosDevice dev) {
+	    Long mac = dev.getMacAddress().toLong();
+	    mapDevice.put(mac, dev);
+	    log.debug("Device added: device mac {}", mac);
+	}
 
-		@Override
-		public void addDeviceEvent(Long mac, OnosDevice dev) {
-			mapDevice.put(mac, dev);
-			log.debug("addDeviceMap: device mac {}", mac);
-		}
+	@Override
+	public void entryRemoved(OnosDevice dev) {
+	    Long mac = dev.getMacAddress().toLong();
+	    mapDevice.remove(mac);
+	    log.debug("Device removed: device mac {}", mac);
+	}
 
-		@Override
-		public void deleteDeviceEvent(Long mac, OnosDevice dev) {
-			mapDevice.remove(mac);
-			log.debug("deleteDeviceMap: device mac {}", mac);
-		}
-
-		@Override
-		public void updateDeviceEvent(Long mac, OnosDevice dev) {
-			mapDevice.put(mac, dev);
-			log.debug("updateDeviceMap: device mac {}", mac);
-		}
-    }
+	@Override
+	public void entryUpdated(OnosDevice dev) {
+	    Long mac = dev.getMacAddress().toLong();
+	    mapDevice.put(mac, dev);
+	    log.debug("Device updated: device mac {}", mac);
+	}
 
 	@Override
 	public void addOnosDeviceListener(IOnosDeviceListener listener) {
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 0ee4466..294e1a5 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/forwarding/Forwarding.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/forwarding/Forwarding.java
@@ -19,10 +19,12 @@
 import net.floodlightcontroller.core.module.IFloodlightService;
 import net.floodlightcontroller.util.MACAddress;
 import net.onrc.onos.datagrid.IDatagridService;
+import net.onrc.onos.datagrid.IEventChannel;
 import net.onrc.onos.ofcontroller.devicemanager.IOnosDeviceService;
 import net.onrc.onos.ofcontroller.flowprogrammer.IFlowPusherService;
 import net.onrc.onos.ofcontroller.proxyarp.BroadcastPacketOutNotification;
 import net.onrc.onos.ofcontroller.proxyarp.IProxyArpService;
+import net.onrc.onos.ofcontroller.proxyarp.PacketOutNotification;
 import net.onrc.onos.ofcontroller.util.CallerId;
 import net.onrc.onos.ofcontroller.util.DataPath;
 import net.onrc.onos.ofcontroller.util.Dpid;
@@ -67,6 +69,14 @@
 	private IFloodlightProviderService floodlightProvider;
 	private IFlowPusherService flowPusher;
 	private IDatagridService datagrid;
+	//
+	// TODO: Using PacketOutNotification as both the key and the
+	// value is a hack that should be removed when this module is
+	// refactored.
+	//
+	private IEventChannel<PacketOutNotification, PacketOutNotification> eventChannel;
+	private static final String PACKET_OUT_CHANNEL_NAME = "onos.packet_out";
+
 	private IControllerRegistryService controllerRegistryService;
 	
 	// TODO it seems there is a Guava collection that will time out entries.
@@ -176,7 +186,14 @@
 	
 	@Override
 	public void startUp(FloodlightModuleContext context) {
-		// no-op
+		//
+		// TODO: Using PacketOutNotification as both the key and the
+		// value is a hack that should be removed when this module is
+		// refactored.
+		//
+		eventChannel = datagrid.createChannel(PACKET_OUT_CHANNEL_NAME,
+						      PacketOutNotification.class,
+						      PacketOutNotification.class);
 	}
 
 	@Override
@@ -231,8 +248,17 @@
 			log.trace("Sending broadcast packet to other ONOS instances");
 		}
 
-		 datagrid.sendPacketOutNotification(new BroadcastPacketOutNotification(
-				 eth.serialize(), null, sw.getId(), pi.getInPort()));
+		PacketOutNotification key =
+		    new BroadcastPacketOutNotification(
+						       eth.serialize(),
+						       null, sw.getId(),
+						       pi.getInPort());
+		//
+		// TODO: Using PacketOutNotification as both the key and the
+		// value is a hack that should be removed when this module is
+		// refactored.
+		//
+		eventChannel.addTransientEntry(key, key);
 	}
 	
 	private void handlePacketIn(IOFSwitch sw, OFPacketIn pi, Ethernet eth){
diff --git a/src/main/java/net/onrc/onos/ofcontroller/proxyarp/IArpReplyEventHandler.java b/src/main/java/net/onrc/onos/ofcontroller/proxyarp/IArpReplyEventHandler.java
deleted file mode 100644
index 98fcf0c..0000000
--- a/src/main/java/net/onrc/onos/ofcontroller/proxyarp/IArpReplyEventHandler.java
+++ /dev/null
@@ -1,12 +0,0 @@
-package net.onrc.onos.ofcontroller.proxyarp;
-
-/**
- * Listener interface for ARP reply event callbacks.
- */
-public interface IArpReplyEventHandler {
-    /**
-     * An ARP reply has been received.
-     * @param arpReply data about the received ARP reply
-     */
-    public void arpReplyEvent(ArpReplyNotification arpReply);
-}
diff --git a/src/main/java/net/onrc/onos/ofcontroller/proxyarp/IPacketOutEventHandler.java b/src/main/java/net/onrc/onos/ofcontroller/proxyarp/IPacketOutEventHandler.java
deleted file mode 100644
index ce98703..0000000
--- a/src/main/java/net/onrc/onos/ofcontroller/proxyarp/IPacketOutEventHandler.java
+++ /dev/null
@@ -1,20 +0,0 @@
-package net.onrc.onos.ofcontroller.proxyarp;
-
-/**
- * Classes may implement this interface if they wish to subscribe to packet out
- * notifications from the datagrid service. Packet out notifications are used to
- * direct other ONOS instances to send packets out particular ports under their
- * control.
- *
- */
-public interface IPacketOutEventHandler {
-
-    /**
-     * Notify the packet out event handler that an packet out notification has
-     * been received.
-     *
-     * @param packetOutNotification An object describing the notification
-     */
-    public void packetOutNotification(
-            PacketOutNotification packetOutNotification);
-}
diff --git a/src/main/java/net/onrc/onos/ofcontroller/proxyarp/ProxyArpManager.java b/src/main/java/net/onrc/onos/ofcontroller/proxyarp/ProxyArpManager.java
index 33d4d7d..d235c37 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/proxyarp/ProxyArpManager.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/proxyarp/ProxyArpManager.java
@@ -22,6 +22,8 @@
 import net.floodlightcontroller.restserver.IRestApiService;
 import net.floodlightcontroller.util.MACAddress;
 import net.onrc.onos.datagrid.IDatagridService;
+import net.onrc.onos.datagrid.IEventChannel;
+import net.onrc.onos.datagrid.IEventChannelListener;
 import net.onrc.onos.ofcontroller.bgproute.Interface;
 import net.onrc.onos.ofcontroller.core.config.IConfigInfoService;
 import net.onrc.onos.ofcontroller.flowprogrammer.IFlowPusherService;
@@ -46,7 +48,7 @@
 import com.google.common.collect.SetMultimap;
 
 public class ProxyArpManager implements IProxyArpService, IOFMessageListener,
-        IPacketOutEventHandler, IArpReplyEventHandler, IFloodlightModule {
+					IFloodlightModule {
     private static final Logger log = LoggerFactory
             .getLogger(ProxyArpManager.class);
 
@@ -56,6 +58,15 @@
 
     private IFloodlightProviderService floodlightProvider;
     private IDatagridService datagrid;
+    private IEventChannel<PacketOutNotification, PacketOutNotification> packetOutEventChannel;
+    private IEventChannel<ArpReplyNotification, ArpReplyNotification> arpReplyEventChannel;
+    private static final String PACKET_OUT_CHANNEL_NAME = "onos.packet_out";
+    private static final String ARP_REPLY_CHANNEL_NAME = "onos.arp_reply";
+    private PacketOutEventHandler packetOutEventHandler =
+	new PacketOutEventHandler();
+    private ArpReplyEventHandler arpReplyEventHandler =
+	new ArpReplyEventHandler();
+
     private IConfigInfoService configService;
     private IRestApiService restApi;
     private IFlowPusherService flowPusher;
@@ -65,6 +76,87 @@
 
     private SetMultimap<InetAddress, ArpRequest> arpRequests;
 
+    //
+    // TODO: Using PacketOutNotification as both the key and the
+    // value is a hack that should be removed when this module is
+    // refactored.
+    //
+    private class PacketOutEventHandler implements
+	IEventChannelListener<PacketOutNotification, PacketOutNotification> {
+	@Override
+	public void entryAdded(PacketOutNotification packetOutNotification) {
+	    if (packetOutNotification instanceof SinglePacketOutNotification) {
+		SinglePacketOutNotification notification =
+		    (SinglePacketOutNotification) packetOutNotification;
+		sendArpRequestOutPort(notification.packet,
+				      notification.getOutSwitch(),
+				      notification.getOutPort());
+
+		// set timestamp
+		InetAddress addr = notification.getTargetAddress();
+		if (addr != null) {
+		    for (ArpRequest request : arpRequests.get(addr)) {
+			request.setRequestTime();
+		    }
+		}
+	    } else if (packetOutNotification instanceof BroadcastPacketOutNotification) {
+		BroadcastPacketOutNotification notification =
+		    (BroadcastPacketOutNotification) packetOutNotification;
+		broadcastArpRequestOutMyEdge(notification.packet,
+					     notification.getInSwitch(),
+					     notification.getInPort());
+
+		// set timestamp
+		InetAddress addr = notification.getTargetAddress();
+		if (addr != null) {
+		    for (ArpRequest request : arpRequests.get(addr)) {
+			request.setRequestTime();
+		    }
+		}
+	    } else {
+		log.warn("Unknown packet out notification received");
+	    }
+	}
+
+	@Override
+	public void entryUpdated(PacketOutNotification packetOutNotification) {
+	    // TODO: For now, entryUpdated() is processed as entryAdded()
+	    entryAdded(packetOutNotification);
+	}
+
+	@Override
+	public void entryRemoved(PacketOutNotification packetOutNotification) {
+	    // TODO: Not implemented. Revisit when this module is refactored
+	}
+    }
+
+    //
+    // TODO: Using ArpReplyNotification as both the key and the
+    // value is a hack that should be removed when this module is
+    // refactored.
+    //
+    private class ArpReplyEventHandler implements
+	IEventChannelListener<ArpReplyNotification, ArpReplyNotification> {
+	@Override
+	public void entryAdded(ArpReplyNotification arpReply) {
+	    log.debug("Received ARP reply notification for {}",
+		      arpReply.getTargetAddress());
+	    sendArpReplyToWaitingRequesters(arpReply.getTargetAddress(),
+					    arpReply.getTargetMacAddress());
+	}
+
+	@Override
+	public void entryUpdated(ArpReplyNotification arpReply) {
+	    // TODO: For now, entryUpdated() is processed as entryAdded()
+	    entryAdded(arpReply);
+	}
+
+	@Override
+	public void entryRemoved(ArpReplyNotification arpReply) {
+	    // TODO: Not implemented. Revisit when this module is refactored
+	}
+    }
+
     private static class ArpRequest {
         private final IArpRequester requester;
         private final boolean retry;
@@ -171,8 +263,22 @@
         restApi.addRestletRoutable(new ArpWebRoutable());
         floodlightProvider.addOFMessageListener(OFType.PACKET_IN, this);
 
-        datagrid.registerPacketOutEventHandler(this);
-        datagrid.registerArpReplyEventHandler(this);
+	//
+	// Event notification setup: channels and event handlers
+	//
+	//
+	// TODO: Using PacketOutNotification or ArpReplyNotification as both
+	// the key and the value is a hack that should be removed when this
+	// module is refactored.
+	//
+	packetOutEventChannel = datagrid.addListener(PACKET_OUT_CHANNEL_NAME,
+						     packetOutEventHandler,
+						     PacketOutNotification.class,
+						     PacketOutNotification.class);
+	arpReplyEventChannel = datagrid.addListener(ARP_REPLY_CHANNEL_NAME,
+						    arpReplyEventHandler,
+						    ArpReplyNotification.class,
+						    ArpReplyNotification.class);
 
         Timer arpTimer = new Timer("arp-processing");
         arpTimer.scheduleAtFixedRate(new TimerTask() {
@@ -348,9 +454,11 @@
         	}
 
         	// We don't know the device so broadcast the request out
-        	datagrid.sendPacketOutNotification(
-        			new BroadcastPacketOutNotification(eth.serialize(),
-        					target, sw.getId(), pi.getInPort()));
+		PacketOutNotification key =
+		    new BroadcastPacketOutNotification(eth.serialize(),
+        					target, sw.getId(),
+						pi.getInPort());
+        	packetOutEventChannel.addTransientEntry(key, key);
         }
         else {
         	// Even if the device exists in our database, we do not reply to
@@ -374,10 +482,11 @@
         			log.trace("Device {} exists but is not connected to any ports" +
         					" - broadcasting", macAddress);
         		}
-
-        		datagrid.sendPacketOutNotification(
-        				new BroadcastPacketOutNotification(eth.serialize(),
-        						target, sw.getId(), pi.getInPort()));
+			PacketOutNotification key =
+			    new BroadcastPacketOutNotification(eth.serialize(),
+					target, sw.getId(),
+					pi.getInPort());
+			packetOutEventChannel.addTransientEntry(key, key);
         	}
         	else {
         		for (IPortObject portObject : outPorts) {
@@ -401,9 +510,10 @@
         						HexString.toHexString(outSwitch), outPort});
         			}
 
-        			datagrid.sendPacketOutNotification(
-        					new SinglePacketOutNotification(eth.serialize(),
-        							target, outSwitch, outPort));
+				PacketOutNotification key =
+        				new SinglePacketOutNotification(eth.serialize(),
+						target, outSwitch, outPort);
+				packetOutEventChannel.addTransientEntry(key, key);
         		}
         	}
         }
@@ -503,8 +613,10 @@
         }
 
         // sendArpRequestToSwitches(ipAddress, eth.serialize());
-        datagrid.sendPacketOutNotification(new SinglePacketOutNotification(eth
-                .serialize(), ipAddress, intf.getDpid(), intf.getPort()));
+	PacketOutNotification key =
+	    new SinglePacketOutNotification(eth.serialize(), ipAddress,
+					    intf.getDpid(), intf.getPort());
+	packetOutEventChannel.addTransientEntry(key, key);
     }
 
     private void sendArpRequestToSwitches(InetAddress dstAddress,
@@ -560,8 +672,9 @@
 
         MACAddress mac = new MACAddress(arp.getSenderHardwareAddress());
 
-        datagrid.sendArpReplyNotification(new ArpReplyNotification(
-                targetAddress, mac));
+	ArpReplyNotification key =
+	    new ArpReplyNotification(targetAddress, mac);
+	arpReplyEventChannel.addTransientEntry(key, key);
     }
 
     private void broadcastArpRequestOutMyEdge(byte[] arpRequest, long inSwitch,
@@ -799,45 +912,4 @@
             request.dispatchReply(address, mac);
         }
     }
-
-    @Override
-    public void arpReplyEvent(ArpReplyNotification arpReply) {
-        log.debug("Received ARP reply notification for {}",
-                arpReply.getTargetAddress());
-        sendArpReplyToWaitingRequesters(arpReply.getTargetAddress(),
-                arpReply.getTargetMacAddress());
-    }
-
-    @Override
-    public void packetOutNotification(
-            PacketOutNotification packetOutNotification) {
-
-        if (packetOutNotification instanceof SinglePacketOutNotification) {
-            SinglePacketOutNotification notification = (SinglePacketOutNotification) packetOutNotification;
-            sendArpRequestOutPort(notification.packet,
-                    notification.getOutSwitch(), notification.getOutPort());
-
-            // set timestamp
-            InetAddress addr = notification.getTargetAddress();
-            if (addr != null) {
-                for (ArpRequest request : arpRequests.get(addr)) {
-                    request.setRequestTime();
-                }
-            }
-        } else if (packetOutNotification instanceof BroadcastPacketOutNotification) {
-            BroadcastPacketOutNotification notification = (BroadcastPacketOutNotification) packetOutNotification;
-            broadcastArpRequestOutMyEdge(notification.packet,
-                    notification.getInSwitch(), notification.getInPort());
-
-            // set timestamp
-            InetAddress addr = notification.getTargetAddress();
-            if (addr != null) {
-                for (ArpRequest request : arpRequests.get(addr)) {
-                    request.setRequestTime();
-                }
-            }
-        } else {
-            log.warn("Unknown packet out notification received");
-        }
-    }
 }