diff --git a/ovsdb/ctl/src/main/java/org/onosproject/ovsdb/controller/impl/OvsdbControllerImpl.java b/ovsdb/ctl/src/main/java/org/onosproject/ovsdb/controller/impl/OvsdbControllerImpl.java
index a0e3de2..f80a89e 100644
--- a/ovsdb/ctl/src/main/java/org/onosproject/ovsdb/controller/impl/OvsdbControllerImpl.java
+++ b/ovsdb/ctl/src/main/java/org/onosproject/ovsdb/controller/impl/OvsdbControllerImpl.java
@@ -1,429 +1,413 @@
-/*
- * Copyright 2015 Open Networking Laboratory
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.onosproject.ovsdb.controller.impl;
-
-import static com.google.common.base.Preconditions.checkNotNull;
-
-import java.math.BigInteger;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
-import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.CopyOnWriteArraySet;
-import java.util.concurrent.ExecutionException;
-
-import org.apache.felix.scr.annotations.Activate;
-import org.apache.felix.scr.annotations.Component;
-import org.apache.felix.scr.annotations.Deactivate;
-import org.apache.felix.scr.annotations.Service;
-import org.onlab.packet.IpAddress;
-import org.onlab.packet.MacAddress;
-import org.onosproject.ovsdb.controller.DefaultEventSubject;
-import org.onosproject.ovsdb.controller.EventSubject;
-import org.onosproject.ovsdb.controller.OvsdbClientService;
-import org.onosproject.ovsdb.controller.OvsdbConstant;
-import org.onosproject.ovsdb.controller.OvsdbController;
-import org.onosproject.ovsdb.controller.OvsdbDatapathId;
-import org.onosproject.ovsdb.controller.OvsdbEvent;
-import org.onosproject.ovsdb.controller.OvsdbEvent.Type;
-import org.onosproject.ovsdb.controller.OvsdbEventListener;
-import org.onosproject.ovsdb.controller.OvsdbIfaceId;
-import org.onosproject.ovsdb.controller.OvsdbNodeId;
-import org.onosproject.ovsdb.controller.OvsdbNodeListener;
-import org.onosproject.ovsdb.controller.OvsdbPortName;
-import org.onosproject.ovsdb.controller.OvsdbPortNumber;
-import org.onosproject.ovsdb.controller.OvsdbPortType;
-import org.onosproject.ovsdb.controller.driver.OvsdbAgent;
-import org.onosproject.ovsdb.rfc.jsonrpc.Callback;
-import org.onosproject.ovsdb.rfc.message.TableUpdate;
-import org.onosproject.ovsdb.rfc.message.TableUpdates;
-import org.onosproject.ovsdb.rfc.message.UpdateNotification;
-import org.onosproject.ovsdb.rfc.notation.OvsdbMap;
-import org.onosproject.ovsdb.rfc.notation.OvsdbSet;
-import org.onosproject.ovsdb.rfc.notation.Row;
-import org.onosproject.ovsdb.rfc.notation.UUID;
-import org.onosproject.ovsdb.rfc.schema.DatabaseSchema;
-import org.onosproject.ovsdb.rfc.table.Bridge;
-import org.onosproject.ovsdb.rfc.table.Interface;
-import org.onosproject.ovsdb.rfc.table.OvsdbTable;
-import org.onosproject.ovsdb.rfc.table.Port;
-import org.onosproject.ovsdb.rfc.table.TableGenerator;
-import org.onosproject.ovsdb.rfc.utils.FromJsonUtil;
-import org.osgi.service.component.ComponentContext;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-import com.fasterxml.jackson.databind.JsonNode;
-
-/**
- * The implementation of OvsdbController.
- */
-@Component(immediate = true)
-@Service
-public class OvsdbControllerImpl implements OvsdbController {
-
-    public static final Logger log = LoggerFactory
-            .getLogger(OvsdbControllerImpl.class);
-
-    protected ConcurrentHashMap<OvsdbNodeId, OvsdbClientService> ovsdbClients =
-            new ConcurrentHashMap<OvsdbNodeId, OvsdbClientService>();
-
-    protected OvsdbAgent agent = new InternalOvsdbNodeAgent();
-    protected InternalMonitorCallBack updateCallback = new InternalMonitorCallBack();
-
-    protected Set<OvsdbNodeListener> ovsdbNodeListener = new CopyOnWriteArraySet<>();
-    protected Set<OvsdbEventListener> ovsdbEventListener = new CopyOnWriteArraySet<>();
-
-    protected ConcurrentHashMap<String, OvsdbClientService> requestNotification =
-            new ConcurrentHashMap<String, OvsdbClientService>();
-
-    protected ConcurrentHashMap<String, String> requestDbName = new ConcurrentHashMap<String, String>();
-
-    private final Controller controller = new Controller();
-
-    @Activate
-    public void activate(ComponentContext context) {
-        controller.start(agent, updateCallback);
-        log.info("Started");
-    }
-
-    @Deactivate
-    public void deactivate() {
-        controller.stop();
-        log.info("Stoped");
-    }
-
-    @Override
-    public void addNodeListener(OvsdbNodeListener listener) {
-        if (!ovsdbNodeListener.contains(listener)) {
-            this.ovsdbNodeListener.add(listener);
-        }
-    }
-
-    @Override
-    public void removeNodeListener(OvsdbNodeListener listener) {
-        this.ovsdbNodeListener.remove(listener);
-    }
-
-    @Override
-    public void addOvsdbEventListener(OvsdbEventListener listener) {
-        if (!ovsdbEventListener.contains(listener)) {
-            this.ovsdbEventListener.add(listener);
-        }
-    }
-
-    @Override
-    public void removeOvsdbEventListener(OvsdbEventListener listener) {
-        this.ovsdbEventListener.remove(listener);
-    }
-
-    @Override
-    public List<OvsdbNodeId> getNodeIds() {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public OvsdbClientService getOvsdbClient(OvsdbNodeId nodeId) {
-        return ovsdbClients.get(nodeId);
-    }
-
-    /**
-     * Implementation of an Ovsdb Agent which is responsible for keeping track
-     * of connected node and the state in which they are.
-     */
-    private class InternalOvsdbNodeAgent implements OvsdbAgent {
-        @Override
-        public void addConnectedNode(OvsdbNodeId nodeId,
-                                     OvsdbClientService ovsdbClient) {
-
-            if (ovsdbClients.get(nodeId) != null) {
-                return;
-            } else {
-                ovsdbClients.put(nodeId, ovsdbClient);
-
-                try {
-                    List<String> dbNames = ovsdbClient.listDbs().get();
-                    for (String dbName : dbNames) {
-                        DatabaseSchema dbSchema;
-                        dbSchema = ovsdbClient.getOvsdbSchema(dbName).get();
-
-                        log.debug("Begin to monitor tables");
-                        String id = java.util.UUID.randomUUID().toString();
-                        TableUpdates updates = ovsdbClient
-                                .monitorTables(dbName, id).get();
-
-                        requestDbName.put(id, dbName);
-                        requestNotification.put(id, ovsdbClient);
-
-                        if (updates != null) {
-                            processTableUpdates(ovsdbClient, updates,
-                                                dbSchema.name());
-                        }
-                    }
-                } catch (InterruptedException e) {
-                    log.warn("Interrupted while waiting to get message from ovsdb");
-                    Thread.currentThread().interrupt();
-                } catch (ExecutionException e) {
-                    log.error("Exception thrown while to get message from ovsdb");
-                }
-
-                log.debug("Add node to north");
-                for (OvsdbNodeListener l : ovsdbNodeListener) {
-                    l.nodeAdded(nodeId);
-                }
-                return;
-            }
-        }
-
-        @Override
-        public void removeConnectedNode(OvsdbNodeId nodeId) {
-            ovsdbClients.remove(nodeId);
-            log.debug("Node connection is removed");
-            for (OvsdbNodeListener l : ovsdbNodeListener) {
-                l.nodeRemoved(nodeId);
-            }
-        }
-    }
-
-    /**
-     * Processes table updates.
-     *
-     * @param clientService OvsdbClientService instance
-     * @param updates TableUpdates instance
-     * @param dbName ovsdb database name
-     */
-    private void processTableUpdates(OvsdbClientService clientService,
-                                     TableUpdates updates, String dbName)
-            throws InterruptedException {
-        checkNotNull(clientService, "OvsdbClientService is not null");
-
-        DatabaseSchema dbSchema = clientService.getDatabaseSchema(dbName);
-
-        for (String tableName : updates.result().keySet()) {
-            TableUpdate update = updates.result().get(tableName);
-            for (UUID uuid : (Set<UUID>) update.rows().keySet()) {
-                log.debug("Begin to process table updates uuid: {}, databaseName: {}, tableName: {}",
-                         uuid.value(), dbName, tableName);
-
-                Row row = clientService.getRow(dbName, tableName, uuid.value());
-                clientService.updateOvsdbStore(dbName, tableName, uuid.value(),
-                                               update.getNew(uuid));
-                if (update.getNew(uuid) != null) {
-                    boolean isNewRow = (row == null) ? true : false;
-                    if (isNewRow) {
-                        if (OvsdbConstant.PORT.equals(tableName)) {
-                            dispatchEvent(clientService, update.getNew(uuid),
-                                          null, OvsdbEvent.Type.PORT_ADDED,
-                                          dbSchema);
-                        }
-                    }
-                } else if (update.getOld(uuid) != null) {
-                    clientService.removeRow(dbName, tableName, uuid.toString());
-                    if (update.getOld(uuid) != null) {
-                        if (OvsdbConstant.PORT.equals(tableName)) {
-                            dispatchEvent(clientService, null,
-                                          update.getOld(uuid),
-                                          OvsdbEvent.Type.PORT_REMOVED,
-                                          dbSchema);
-                        }
-                    }
-                }
-            }
-        }
-    }
-
-    /**
-     * Dispatches event to the north.
-     *
-     * @param clientService OvsdbClientService instance
-     * @param newRow a new row
-     * @param oldRow an old row
-     * @param eventType type of event
-     * @param dbSchema ovsdb database schema
-     */
-    private void dispatchEvent(OvsdbClientService clientService, Row newRow,
-                               Row oldRow, Type eventType,
-                               DatabaseSchema dbSchema) {
-        Port port = null;
-        if (OvsdbEvent.Type.PORT_ADDED.equals(eventType)) {
-            port = (Port) TableGenerator.getTable(dbSchema, newRow,
-                                                  OvsdbTable.PORT);
-        } else if (OvsdbEvent.Type.PORT_REMOVED.equals(eventType)) {
-            port = (Port) TableGenerator.getTable(dbSchema, oldRow,
-                                                  OvsdbTable.PORT);
-        }
-        if (port == null) {
-            return;
-        }
-
-        long dpid = getDataPathid(clientService, dbSchema);
-        OvsdbSet intfUuidSet = (OvsdbSet) port.getInterfacesColumn().data();
-        @SuppressWarnings({ "unchecked" })
-        Set<UUID> intfUuids = intfUuidSet.set();
-        for (UUID intfUuid : intfUuids) {
-            Row intfRow = clientService
-                    .getRow(OvsdbConstant.DATABASENAME, "Interface",
-                            intfUuid.toString());
-            if (intfRow == null) {
-                continue;
-            }
-            Interface intf = (Interface) TableGenerator
-                    .getTable(dbSchema, intfRow, OvsdbTable.INTERFACE);
-
-            String portType = (String) intf.getTypeColumn().data();
-            long localPort = getOfPort(intf);
-            String[] macAndIfaceId = getMacAndIfaceid(intf);
-            if (macAndIfaceId == null) {
-                return;
-            }
-            EventSubject eventSubject = new DefaultEventSubject(
-                                                                MacAddress
-                                                                        .valueOf(macAndIfaceId[0]),
-                                                                new HashSet<IpAddress>(),
-                                                                new OvsdbPortName(port.getName()),
-                                                                new OvsdbPortNumber(localPort),
-                                                                new OvsdbDatapathId(Long.toString(dpid)),
-                                                                new OvsdbPortType(portType),
-                                                                new OvsdbIfaceId(macAndIfaceId[1]));
-            for (OvsdbEventListener listener : ovsdbEventListener) {
-                listener.handle(new OvsdbEvent<EventSubject>(eventType,
-                                                             eventSubject));
-            }
-
-        }
-
-    }
-
-    /**
-     * Gets mac and iface from the table Interface.
-     *
-     * @param intf Interface instance
-     * @return attachedMac, ifaceid
-     */
-    private String[] getMacAndIfaceid(Interface intf) {
-        OvsdbMap ovsdbMap = (OvsdbMap) intf.getExternalIdsColumn().data();
-        @SuppressWarnings("unchecked")
-        Map<String, String> externalIds = ovsdbMap.map();
-        if (externalIds == null) {
-            log.warn("The external_ids is null");
-            return null;
-        }
-
-        String attachedMac = externalIds.get(OvsdbConstant.EXTERNAL_ID_VM_MAC);
-        if (attachedMac == null) {
-            log.warn("The attachedMac is null");
-            return null;
-        }
-        String ifaceid = externalIds
-                .get(OvsdbConstant.EXTERNAL_ID_INTERFACE_ID);
-        if (ifaceid == null) {
-            log.warn("The ifaceid is null");
-            return null;
-        }
-        return new String[] {attachedMac, ifaceid};
-    }
-
-    /**
-     * Gets ofPorts number from table Interface.
-     *
-     * @param intf Interface instance
-     * @return ofport the ofport number
-     */
-    private long getOfPort(Interface intf) {
-        OvsdbSet ovsdbSet = (OvsdbSet) intf.getOpenFlowPortColumn().data();
-        @SuppressWarnings("unchecked")
-        Set<Long> ofPorts = ovsdbSet.set();
-        while (ofPorts == null || ofPorts.size() <= 0) {
-            log.debug("The ofport is null in {}", intf.getName());
-            return 0;
-        }
-        return (long) ofPorts.toArray()[0];
-    }
-
-    /**
-     * Gets datapathid from table bridge.
-     *
-     * @param clientService OvsdbClientService instance
-     * @param dbSchema ovsdb database schema
-     * @return datapathid the bridge datapathid
-     */
-    private long getDataPathid(OvsdbClientService clientService,
-                               DatabaseSchema dbSchema) {
-        String bridgeUuid = clientService
-                .getBridgeUuid(OvsdbConstant.INTEGRATION_BRIDGE);
-        if (bridgeUuid == null) {
-            log.debug("Unable to spot bridge uuid for {} in {}",
-                     OvsdbConstant.INTEGRATION_BRIDGE, clientService);
-            return 0;
-        }
-
-        Row bridgeRow = clientService.getRow(OvsdbConstant.DATABASENAME,
-                                             "Bridge", bridgeUuid);
-        Bridge bridge = (Bridge) TableGenerator.getTable(dbSchema, bridgeRow,
-                                                         OvsdbTable.BRIDGE);
-        OvsdbSet ovsdbSet = (OvsdbSet) bridge.getDatapathIdColumn().data();
-        @SuppressWarnings("unchecked")
-        Set<String> dpids = ovsdbSet.set();
-        if (dpids == null || dpids.size() == 0) {
-            return 0;
-        }
-        return stringToLong((String) dpids.toArray()[0]);
-    }
-
-    private long stringToLong(String values) {
-        long value = (new BigInteger(values.replaceAll(":", ""), 16))
-                .longValue();
-        return value;
-    }
-
-    /**
-     * Implementation of an Callback which is responsible for receiving request
-     * infomation from ovsdb.
-     */
-    private class InternalMonitorCallBack implements Callback {
-        @Override
-        public void update(UpdateNotification updateNotification) {
-            Object key = updateNotification.jsonValue();
-            OvsdbClientService ovsdbClient = requestNotification.get(key);
-
-            String dbName = requestDbName.get(key);
-            JsonNode updatesJson = updateNotification.tbUpdatesJsonNode();
-            DatabaseSchema dbSchema = ovsdbClient.getDatabaseSchema(dbName);
-            TableUpdates updates = FromJsonUtil
-                    .jsonNodeToTableUpdates(updatesJson, dbSchema);
-            try {
-                processTableUpdates(ovsdbClient, updates, dbName);
-            } catch (InterruptedException e) {
-                log.warn("Interrupted while processing table updates");
-                Thread.currentThread().interrupt();
-            }
-        }
-
-        @Override
-        public void locked(List<String> ids) {
-            // TODO Auto-generated method stub
-        }
-
-        @Override
-        public void stolen(List<String> ids) {
-            // TODO Auto-generated method stub
-        }
-
-    }
-
-}
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.ovsdb.controller.impl;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import java.math.BigInteger;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.CopyOnWriteArraySet;
+import java.util.concurrent.ExecutionException;
+
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Service;
+import org.onlab.packet.IpAddress;
+import org.onlab.packet.MacAddress;
+import org.onosproject.ovsdb.controller.DefaultEventSubject;
+import org.onosproject.ovsdb.controller.EventSubject;
+import org.onosproject.ovsdb.controller.OvsdbClientService;
+import org.onosproject.ovsdb.controller.OvsdbConstant;
+import org.onosproject.ovsdb.controller.OvsdbController;
+import org.onosproject.ovsdb.controller.OvsdbDatapathId;
+import org.onosproject.ovsdb.controller.OvsdbEvent;
+import org.onosproject.ovsdb.controller.OvsdbEvent.Type;
+import org.onosproject.ovsdb.controller.OvsdbEventListener;
+import org.onosproject.ovsdb.controller.OvsdbIfaceId;
+import org.onosproject.ovsdb.controller.OvsdbNodeId;
+import org.onosproject.ovsdb.controller.OvsdbNodeListener;
+import org.onosproject.ovsdb.controller.OvsdbPortName;
+import org.onosproject.ovsdb.controller.OvsdbPortNumber;
+import org.onosproject.ovsdb.controller.OvsdbPortType;
+import org.onosproject.ovsdb.controller.driver.OvsdbAgent;
+import org.onosproject.ovsdb.rfc.jsonrpc.Callback;
+import org.onosproject.ovsdb.rfc.message.TableUpdate;
+import org.onosproject.ovsdb.rfc.message.TableUpdates;
+import org.onosproject.ovsdb.rfc.message.UpdateNotification;
+import org.onosproject.ovsdb.rfc.notation.OvsdbMap;
+import org.onosproject.ovsdb.rfc.notation.OvsdbSet;
+import org.onosproject.ovsdb.rfc.notation.Row;
+import org.onosproject.ovsdb.rfc.notation.UUID;
+import org.onosproject.ovsdb.rfc.schema.DatabaseSchema;
+import org.onosproject.ovsdb.rfc.table.Bridge;
+import org.onosproject.ovsdb.rfc.table.Interface;
+import org.onosproject.ovsdb.rfc.table.OvsdbTable;
+import org.onosproject.ovsdb.rfc.table.TableGenerator;
+import org.onosproject.ovsdb.rfc.utils.FromJsonUtil;
+import org.osgi.service.component.ComponentContext;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.fasterxml.jackson.databind.JsonNode;
+
+/**
+ * The implementation of OvsdbController.
+ */
+@Component(immediate = true)
+@Service
+public class OvsdbControllerImpl implements OvsdbController {
+
+    public static final Logger log = LoggerFactory
+            .getLogger(OvsdbControllerImpl.class);
+
+    protected ConcurrentHashMap<OvsdbNodeId, OvsdbClientService> ovsdbClients =
+            new ConcurrentHashMap<OvsdbNodeId, OvsdbClientService>();
+
+    protected OvsdbAgent agent = new InternalOvsdbNodeAgent();
+    protected InternalMonitorCallBack updateCallback = new InternalMonitorCallBack();
+
+    protected Set<OvsdbNodeListener> ovsdbNodeListener = new CopyOnWriteArraySet<>();
+    protected Set<OvsdbEventListener> ovsdbEventListener = new CopyOnWriteArraySet<>();
+
+    protected ConcurrentHashMap<String, OvsdbClientService> requestNotification =
+            new ConcurrentHashMap<String, OvsdbClientService>();
+
+    protected ConcurrentHashMap<String, String> requestDbName = new ConcurrentHashMap<String, String>();
+
+    private final Controller controller = new Controller();
+
+    @Activate
+    public void activate(ComponentContext context) {
+        controller.start(agent, updateCallback);
+        log.info("Started");
+    }
+
+    @Deactivate
+    public void deactivate() {
+        controller.stop();
+        log.info("Stoped");
+    }
+
+    @Override
+    public void addNodeListener(OvsdbNodeListener listener) {
+        if (!ovsdbNodeListener.contains(listener)) {
+            this.ovsdbNodeListener.add(listener);
+        }
+    }
+
+    @Override
+    public void removeNodeListener(OvsdbNodeListener listener) {
+        this.ovsdbNodeListener.remove(listener);
+    }
+
+    @Override
+    public void addOvsdbEventListener(OvsdbEventListener listener) {
+        if (!ovsdbEventListener.contains(listener)) {
+            this.ovsdbEventListener.add(listener);
+        }
+    }
+
+    @Override
+    public void removeOvsdbEventListener(OvsdbEventListener listener) {
+        this.ovsdbEventListener.remove(listener);
+    }
+
+    @Override
+    public List<OvsdbNodeId> getNodeIds() {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    @Override
+    public OvsdbClientService getOvsdbClient(OvsdbNodeId nodeId) {
+        return ovsdbClients.get(nodeId);
+    }
+
+    /**
+     * Implementation of an Ovsdb Agent which is responsible for keeping track
+     * of connected node and the state in which they are.
+     */
+    private class InternalOvsdbNodeAgent implements OvsdbAgent {
+        @Override
+        public void addConnectedNode(OvsdbNodeId nodeId,
+                                     OvsdbClientService ovsdbClient) {
+
+            if (ovsdbClients.get(nodeId) != null) {
+                return;
+            } else {
+                ovsdbClients.put(nodeId, ovsdbClient);
+
+                try {
+                    List<String> dbNames = ovsdbClient.listDbs().get();
+                    for (String dbName : dbNames) {
+                        DatabaseSchema dbSchema;
+                        dbSchema = ovsdbClient.getOvsdbSchema(dbName).get();
+
+                        log.debug("Begin to monitor tables");
+                        String id = java.util.UUID.randomUUID().toString();
+                        TableUpdates updates = ovsdbClient
+                                .monitorTables(dbName, id).get();
+
+                        requestDbName.put(id, dbName);
+                        requestNotification.put(id, ovsdbClient);
+
+                        if (updates != null) {
+                            processTableUpdates(ovsdbClient, updates,
+                                                dbSchema.name());
+                        }
+                    }
+                } catch (InterruptedException e) {
+                    log.warn("Interrupted while waiting to get message from ovsdb");
+                    Thread.currentThread().interrupt();
+                } catch (ExecutionException e) {
+                    log.error("Exception thrown while to get message from ovsdb");
+                }
+
+                log.debug("Add node to north");
+                for (OvsdbNodeListener l : ovsdbNodeListener) {
+                    l.nodeAdded(nodeId);
+                }
+                return;
+            }
+        }
+
+        @Override
+        public void removeConnectedNode(OvsdbNodeId nodeId) {
+            ovsdbClients.remove(nodeId);
+            log.debug("Node connection is removed");
+            for (OvsdbNodeListener l : ovsdbNodeListener) {
+                l.nodeRemoved(nodeId);
+            }
+        }
+    }
+
+    /**
+     * Processes table updates.
+     *
+     * @param clientService OvsdbClientService instance
+     * @param updates TableUpdates instance
+     * @param dbName ovsdb database name
+     */
+    private void processTableUpdates(OvsdbClientService clientService,
+                                     TableUpdates updates, String dbName)
+            throws InterruptedException {
+        checkNotNull(clientService, "OvsdbClientService is not null");
+
+        DatabaseSchema dbSchema = clientService.getDatabaseSchema(dbName);
+
+        for (String tableName : updates.result().keySet()) {
+            TableUpdate update = updates.result().get(tableName);
+            for (UUID uuid : (Set<UUID>) update.rows().keySet()) {
+                log.debug("Begin to process table updates uuid: {}, databaseName: {}, tableName: {}",
+                          uuid.value(), dbName, tableName);
+
+                Row oldRow = update.getOld(uuid);
+                Row newRow = update.getNew(uuid);
+                if (newRow != null) {
+                    clientService.updateOvsdbStore(dbName, tableName,
+                                                   uuid.value(), newRow);
+
+                    if (OvsdbConstant.INTERFACE.equals(tableName)) {
+                        dispatchInterfaceEvent(clientService,
+                                               newRow, null,
+                                               OvsdbEvent.Type.PORT_ADDED,
+                                               dbSchema);
+                    }
+                } else if (update.getOld(uuid) != null) {
+                    clientService.removeRow(dbName, tableName, uuid.value());
+                    if (OvsdbConstant.PORT.equals(tableName)) {
+                        dispatchInterfaceEvent(clientService, null,
+                                               oldRow,
+                                          OvsdbEvent.Type.PORT_REMOVED,
+                                          dbSchema);
+                    }
+                }
+            }
+        }
+    }
+
+    /**
+     * Dispatches event to the north.
+     *
+     * @param clientService OvsdbClientService instance
+     * @param newRow a new row
+     * @param oldRow an old row
+     * @param eventType type of event
+     * @param dbSchema ovsdb database schema
+     */
+    private void dispatchInterfaceEvent(OvsdbClientService clientService,
+                                        Row newRow, Row oldRow,
+                                        Type eventType,
+                                        DatabaseSchema dbSchema) {
+
+        long dpid = getDataPathid(clientService, dbSchema);
+        Interface intf = (Interface) TableGenerator
+                .getTable(dbSchema, newRow, OvsdbTable.INTERFACE);
+        if (intf == null) {
+            return;
+        }
+
+        String portType = (String) intf.getTypeColumn().data();
+        long localPort = getOfPort(intf);
+        if (localPort < 0) {
+            return;
+        }
+        String[] macAndIfaceId = getMacAndIfaceid(intf);
+        if (macAndIfaceId == null) {
+            return;
+        }
+
+        EventSubject eventSubject = new DefaultEventSubject(MacAddress.valueOf(
+                                                                               macAndIfaceId[0]),
+                                                            new HashSet<IpAddress>(),
+                                                            new OvsdbPortName(intf
+                                                                    .getName()),
+                                                            new OvsdbPortNumber(localPort),
+                                                            new OvsdbDatapathId(Long
+                                                                    .toString(dpid)),
+                                                            new OvsdbPortType(portType),
+                                                            new OvsdbIfaceId(macAndIfaceId[1]));
+        for (OvsdbEventListener listener : ovsdbEventListener) {
+            listener.handle(new OvsdbEvent<EventSubject>(eventType,
+                                                         eventSubject));
+        }
+    }
+
+    /**
+     * Gets mac and iface from the table Interface.
+     *
+     * @param intf Interface instance
+     * @return attachedMac, ifaceid
+     */
+    private String[] getMacAndIfaceid(Interface intf) {
+        OvsdbMap ovsdbMap = (OvsdbMap) intf.getExternalIdsColumn().data();
+        @SuppressWarnings("unchecked")
+        Map<String, String> externalIds = ovsdbMap.map();
+        if (externalIds == null) {
+            log.warn("The external_ids is null");
+            return null;
+        }
+
+        String attachedMac = externalIds.get(OvsdbConstant.EXTERNAL_ID_VM_MAC);
+        if (attachedMac == null) {
+            log.warn("The attachedMac is null");
+            return null;
+        }
+        String ifaceid = externalIds
+                .get(OvsdbConstant.EXTERNAL_ID_INTERFACE_ID);
+        if (ifaceid == null) {
+            log.warn("The ifaceid is null");
+            return null;
+        }
+        return new String[] {attachedMac, ifaceid};
+    }
+
+    /**
+     * Gets ofPorts number from table Interface.
+     *
+     * @param intf Interface instance
+     * @return ofport the ofport number
+     */
+    private long getOfPort(Interface intf) {
+        OvsdbSet ofPortSet = (OvsdbSet) intf.getOpenFlowPortColumn().data();
+        @SuppressWarnings("unchecked")
+        Set<Integer> ofPorts = ofPortSet.set();
+        while (ofPorts == null || ofPorts.size() <= 0) {
+            log.debug("The ofport is null in {}", intf.getName());
+            return -1;
+        }
+        Iterator<Integer> it = ofPorts.iterator();
+        return Long.parseLong(it.next().toString());
+    }
+
+    /**
+     * Gets datapathid from table bridge.
+     *
+     * @param clientService OvsdbClientService instance
+     * @param dbSchema ovsdb database schema
+     * @return datapathid the bridge datapathid
+     */
+    private long getDataPathid(OvsdbClientService clientService,
+                               DatabaseSchema dbSchema) {
+        String bridgeUuid = clientService
+                .getBridgeUuid(OvsdbConstant.INTEGRATION_BRIDGE);
+        if (bridgeUuid == null) {
+            log.debug("Unable to spot bridge uuid for {} in {}",
+                      OvsdbConstant.INTEGRATION_BRIDGE, clientService);
+            return 0;
+        }
+
+        Row bridgeRow = clientService.getRow(OvsdbConstant.DATABASENAME,
+                                             "Bridge", bridgeUuid);
+        Bridge bridge = (Bridge) TableGenerator.getTable(dbSchema, bridgeRow,
+                                                         OvsdbTable.BRIDGE);
+        OvsdbSet dpidSet = (OvsdbSet) bridge.getDatapathIdColumn().data();
+        @SuppressWarnings("unchecked")
+        Set<String> dpids = dpidSet.set();
+        if (dpids == null || dpids.size() == 0) {
+            return 0;
+        }
+        return stringToLong((String) dpids.toArray()[0]);
+    }
+
+    private long stringToLong(String values) {
+        long value = (new BigInteger(values.replaceAll(":", ""), 16))
+                .longValue();
+        return value;
+    }
+
+    /**
+     * Implementation of an Callback which is responsible for receiving request
+     * infomation from ovsdb.
+     */
+    private class InternalMonitorCallBack implements Callback {
+        @Override
+        public void update(UpdateNotification updateNotification) {
+            Object key = updateNotification.jsonValue();
+            OvsdbClientService ovsdbClient = requestNotification.get(key);
+
+            String dbName = requestDbName.get(key);
+            JsonNode updatesJson = updateNotification.tbUpdatesJsonNode();
+            DatabaseSchema dbSchema = ovsdbClient.getDatabaseSchema(dbName);
+            TableUpdates updates = FromJsonUtil
+                    .jsonNodeToTableUpdates(updatesJson, dbSchema);
+            try {
+                processTableUpdates(ovsdbClient, updates, dbName);
+            } catch (InterruptedException e) {
+                log.warn("Interrupted while processing table updates");
+                Thread.currentThread().interrupt();
+            }
+        }
+
+        @Override
+        public void locked(List<String> ids) {
+            // TODO Auto-generated method stub
+        }
+
+        @Override
+        public void stolen(List<String> ids) {
+            // TODO Auto-generated method stub
+        }
+
+    }
+
+}