diff --git a/src/main/java/net/onrc/onos/ofcontroller/core/internal/DeviceStorageImpl.java b/src/main/java/net/onrc/onos/ofcontroller/core/internal/DeviceStorageImpl.java
new file mode 100644
index 0000000..5b3ed74
--- /dev/null
+++ b/src/main/java/net/onrc/onos/ofcontroller/core/internal/DeviceStorageImpl.java
@@ -0,0 +1,269 @@
+package net.onrc.onos.ofcontroller.core.internal;
+
+import java.util.ArrayList;
+import java.util.List;
+import org.openflow.util.HexString;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.common.collect.Lists;
+import com.thinkaurelius.titan.core.TitanException;
+import net.floodlightcontroller.devicemanager.IDevice;
+import net.floodlightcontroller.devicemanager.SwitchPort;
+import net.floodlightcontroller.packet.IPv4;
+import net.onrc.onos.ofcontroller.core.IDeviceStorage;
+import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IDeviceObject;
+import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IPortObject;
+import net.onrc.onos.util.GraphDBConnection;
+import net.onrc.onos.util.GraphDBConnection.Transaction;
+import net.onrc.onos.util.GraphDBOperation;
+
+/**
+ * This is the class for storing the information of devices into CassandraDB
+ * @author Pankaj
+ */
+public class DeviceStorageImpl implements IDeviceStorage {
+	
+	private GraphDBConnection conn;
+	private GraphDBOperation ope;
+	protected static Logger log = LoggerFactory.getLogger(SwitchStorageImpl.class);
+
+	/***
+	 * Initialize function. Before you use this class, please call this method
+	 * @param conf configuration file for Cassandra DB
+	 */
+	@Override
+	public void init(String conf) {
+		try{
+			if((conn = GraphDBConnection.getInstance(conf)) != null)
+			{
+				ope = new GraphDBOperation(conn);
+			}
+		} catch(Exception e) {
+			log.error(e.getMessage());
+		}
+	}	
+	
+	/***
+	 * Finalize/close function. After you use this class, please call this method.
+	 * It will close the DB connection.
+	 */
+	@Override
+	public void close() {
+		conn.close();
+	}
+	
+	/***
+	 * Finalize/close function. After you use this class, please call this method.
+	 * It will close the DB connection. This is for Java gabage collection.
+	 */
+	@Override
+	public void finalize() {
+		close();
+	}
+
+	/***
+	 * This function is for adding the device into the DB.
+	 * @param device The device you want to add into the DB.
+	 * @return IDeviceObject which was added in the DB. 
+	 */
+	@Override
+	public IDeviceObject addDevice(IDevice device) {
+		IDeviceObject obj = null;
+ 		try {
+ 			if ((obj = ope.searchDevice(device.getMACAddressString())) != null) {
+ 				log.debug("Adding device {}: found existing device",device.getMACAddressString());
+            } else {
+            	obj = ope.newDevice();
+                log.debug("Adding device {}: creating new device",device.getMACAddressString());
+            }
+	            changeDeviceAttachments(device, obj);
+	
+				String multiIntString = "";
+				for(Integer intValue : device.getIPv4Addresses()) {
+				   if (multiIntString == null || multiIntString.isEmpty()){
+				     multiIntString = IPv4.fromIPv4Address(intValue);
+				     multiIntString = "[" + IPv4.fromIPv4Address(intValue);
+				   }else{
+				        multiIntString += "," + IPv4.fromIPv4Address(intValue);
+				   }
+				}
+	 	            
+	            if(multiIntString.toString() != null && !multiIntString.toString().isEmpty()){
+	            	obj.setIPAddress(multiIntString + "]");
+	            }
+	            
+	 			obj.setMACAddress(device.getMACAddressString());
+	 			obj.setType("device");
+	 			obj.setState("ACTIVE");
+	 			ope.commit();
+ 			
+	 			log.debug("Adding device {}",device.getMACAddressString());
+		} catch (Exception e) {
+			ope.rollback();
+			log.error(":addDevice mac:{} failed", device.getMACAddressString());
+			obj = null;
+		}	
+ 			return obj;		
+	}
+
+	/***
+	 * This function is for updating the Device properties.
+	 * @param device The device you want to add into the DB.
+	 * @return IDeviceObject which was added in the DB. 
+	 */
+	@Override
+	public IDeviceObject updateDevice(IDevice device) {
+		return addDevice(device);
+	}
+
+	/***
+	 * This function is for removing the Device from the DB.
+	 * @param device The device you want to delete from the DB.
+	 */
+	@Override
+	public void removeDevice(IDevice device) {
+		IDeviceObject dev;
+		try {
+			if ((dev = ope.searchDevice(device.getMACAddressString())) != null) {
+             	ope.removeDevice(dev);
+             	ope.commit();
+            	log.error("DeviceStorage:removeDevice mac:{} done", device.getMACAddressString());
+            }
+		} catch (Exception e) {
+			ope.rollback();
+			log.error("DeviceStorage:removeDevice mac:{} failed", device.getMACAddressString());
+		}
+	}
+
+	/***
+	 * This function is for getting the Device from the DB by Mac address of the device.
+	 * @param mac The device mac address you want to get from the DB.
+	 * @return IDeviceObject you want to get.
+	 */
+	@Override
+	public IDeviceObject getDeviceByMac(String mac) {
+		return ope.searchDevice(mac);
+	}
+
+	/***
+	 * This function is for getting the Device from the DB by IP address of the device.
+	 * @param ip The device ip address you want to get from the DB.
+	 * @return IDeviceObject you want to get.
+	 */
+	@Override
+	public IDeviceObject getDeviceByIP(String ip) {
+		try
+		{
+			for(IDeviceObject dev : ope.getDevices()){
+				String ips;
+				if((ips = dev.getIPAddress()) != null){
+					String nw_addr_wob = ips.replace("[", "").replace("]", "");
+					ArrayList<String> iplists = Lists.newArrayList(nw_addr_wob.split(","));	
+					if(iplists.contains(ip)){
+						return dev;
+					}
+				}
+			}
+			return null;
+		}
+		catch (Exception e)
+		{
+			log.error("DeviceStorage:getDeviceByIP:{} failed");
+			return null;
+		}
+	}
+
+	/***
+	 * This function is for changing the Device attachment point.
+	 * @param device The device you want change the attachment point
+	 */
+	@Override
+	public void changeDeviceAttachments(IDevice device) {
+		IDeviceObject obj = null;
+ 		try {
+            if ((obj = ope.searchDevice(device.getMACAddressString())) != null) {
+                log.debug("Changing device ports {}: found existing device",device.getMACAddressString());
+                changeDeviceAttachments(device, obj);
+                ope.commit();
+            } else {
+   				log.debug("failed to search device...now adding {}",device.getMACAddressString());
+   				addDevice(device);
+            }            			
+		} catch (Exception e) {
+			ope.rollback();
+			log.error(":addDevice mac:{} failed", device.getMACAddressString());
+		}	
+	}
+	
+	/***
+	 * This function is for changing the Device attachment point.
+	 * @param device The new device you want change the attachment point
+	 * @param obj The old device IDeviceObject that is going to change the attachment point.
+	 */
+	public void changeDeviceAttachments(IDevice device, IDeviceObject obj) {
+		SwitchPort[] attachmentPoints = device.getAttachmentPoints();
+		List<IPortObject> attachedPorts = Lists.newArrayList(obj.getAttachedPorts());
+		
+        for (SwitchPort ap : attachmentPoints) {
+        	//Check weather there is the port
+          	 IPortObject port = ope.searchPort( HexString.toHexString(ap.getSwitchDPID()),
+												(short) ap.getPort());
+          	 log.debug("New Switch Port is {},{}", HexString.toHexString(ap.getSwitchDPID()),(short) ap.getPort());
+	       	 
+	       	 if(port != null){
+	   			if(attachedPorts.contains(port))
+	       		{
+		       		log.debug("This is the port you already attached {}: do nothing",device.getMACAddressString());
+		       		//This port will be remained, so remove from the removed port lists.
+		       		attachedPorts.remove(port);
+		       	} else {
+	     		   log.debug("Adding device {}: attaching to port",device.getMACAddressString());
+		       		port.setDevice(obj);  
+		        }
+	    	
+		       	log.debug("port number is {}", port.getNumber().toString());
+		        log.debug("port desc is {}", port.getDesc());  
+	       	 }
+        }      		 
+	            
+	    for (IPortObject port: attachedPorts) {
+            log.debug("Detouching the device {}: detouching from port",device.getMACAddressString());
+       		port.removeDevice(obj);
+        }
+	}
+
+	/***
+	 * This function is for changing the Device IPv4 address.
+	 * @param device The new device you want change the ipaddress
+	 */
+	@Override
+	public void changeDeviceIPv4Address(IDevice device) {
+		IDeviceObject obj;
+  		try {
+  			if ((obj = ope.searchDevice(device.getMACAddressString())) != null) {
+
+  				String multiIntString = "";
+  				for(Integer intValue : device.getIPv4Addresses()){
+  				   if (multiIntString == null || multiIntString.isEmpty()){
+  				     multiIntString = "[" + IPv4.fromIPv4Address(intValue);
+  				   } else {
+  				        multiIntString += "," + IPv4.fromIPv4Address(intValue);
+  				   }
+  				}
+  				
+  	            if(multiIntString != null && !multiIntString.isEmpty()){
+  	            	obj.setIPAddress(multiIntString + "]");
+  	            }
+  	            
+              	ope.commit();
+  			} else {
+            	log.error(":changeDeviceIPv4Address mac:{} failed", device.getMACAddressString());
+            }		
+  		} catch (TitanException e) {
+  			ope.rollback();
+			log.error(":changeDeviceIPv4Address mac:{} failed due to exception {}", device.getMACAddressString(),e);
+		}
+	}
+
+}
diff --git a/src/main/java/net/onrc/onos/ofcontroller/core/internal/LinkStorageImpl.java b/src/main/java/net/onrc/onos/ofcontroller/core/internal/LinkStorageImpl.java
new file mode 100644
index 0000000..f3de81d
--- /dev/null
+++ b/src/main/java/net/onrc/onos/ofcontroller/core/internal/LinkStorageImpl.java
@@ -0,0 +1,262 @@
+package net.onrc.onos.ofcontroller.core.internal;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import net.floodlightcontroller.linkdiscovery.LinkInfo;
+import net.floodlightcontroller.routing.Link;
+import net.onrc.onos.ofcontroller.core.ILinkStorage;
+import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IPortObject;
+import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.ISwitchObject;
+import net.onrc.onos.util.GraphDBConnection;
+import net.onrc.onos.util.GraphDBOperation;
+
+import org.openflow.util.HexString;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.thinkaurelius.titan.core.TitanException;
+import com.tinkerpop.blueprints.Direction;
+import com.tinkerpop.blueprints.Edge;
+import com.tinkerpop.blueprints.Vertex;
+import com.tinkerpop.gremlin.java.GremlinPipeline;
+import com.tinkerpop.pipes.PipeFunction;
+import com.tinkerpop.pipes.transform.PathPipe;
+
+public class LinkStorageImpl implements ILinkStorage {
+	
+	protected static Logger log = LoggerFactory.getLogger(LinkStorageImpl.class);
+	protected GraphDBOperation dbop;
+
+	@Override
+	public void update(Link link, DM_OPERATION op) {
+		update(link, (LinkInfo)null, op);
+	}
+
+	@Override
+	public void update(List<Link> links, DM_OPERATION op) {
+		for (Link lt: links) {
+			update(lt, (LinkInfo)null, op);
+		}
+	}
+
+	@Override
+	public void update(Link link, LinkInfo linkinfo, DM_OPERATION op) {
+		switch (op) {
+		case UPDATE:
+		case CREATE:
+		case INSERT:
+			updateLink(link, linkinfo, op);
+			break;
+		case DELETE:
+			deleteLink(link);
+			break;
+		}
+	}
+	
+	public void updateLink(Link lt, LinkInfo linkinfo, DM_OPERATION op) {
+		IPortObject vportSrc = null, vportDst = null;
+	
+		log.trace("updateLink(): op {} {} {}", new Object[]{op, lt, linkinfo});
+		
+        try {
+            // get source port vertex
+        	String dpid = HexString.toHexString(lt.getSrc());
+        	short port = lt.getSrcPort();
+        	vportSrc = dbop.searchPort(dpid, port);
+            
+            // get dest port vertex
+            dpid = HexString.toHexString(lt.getDst());
+            port = lt.getDstPort();
+            vportDst = dbop.searchPort(dpid, port);
+                        
+            if (vportSrc != null && vportDst != null) {
+         	       	
+            	// check if the link exists
+            	
+            	Iterable<IPortObject> currPorts = vportSrc.getLinkedPorts();
+            	List<IPortObject> currLinks = new ArrayList<IPortObject>();
+            	for (IPortObject V : currPorts) {
+            		currLinks.add(V);
+            	}
+            	
+            	if (currLinks.contains(vportDst)) {
+            		// TODO: update linkinfo
+            		if (op.equals(DM_OPERATION.INSERT) || op.equals(DM_OPERATION.CREATE)) {
+            			log.debug("addOrUpdateLink(): failed link exists {} {} src {} dst {}", 
+            					new Object[]{op, lt, vportSrc, vportDst});
+            		}
+            	} else {
+            		vportSrc.setLinkPort(vportDst);
+
+            		dbop.commit();
+            		log.debug("updateLink(): link added {} {} src {} dst {}", new Object[]{op, lt, vportSrc, vportDst});
+            	}
+            } else {
+            	log.error("updateLink(): failed invalid vertices {} {} src {} dst {}", new Object[]{op, lt, vportSrc, vportDst});
+            	dbop.rollback();
+            }
+        } catch (TitanException e) {
+            /*
+             * retry till we succeed?
+             */
+        	e.printStackTrace();
+        	log.error("updateLink(): titan exception {} {} {}", new Object[]{op, lt, e.toString()});
+        }
+	}
+	
+	@Override
+	public void deleteLinks(List<Link> links) {
+
+		for (Link lt : links) {
+			deleteLink(lt);
+		}
+	}
+	
+
+	@Override
+	public void deleteLink(Link lt) {
+		IPortObject vportSrc = null, vportDst = null;
+		int count = 0;
+		
+		log.debug("deleteLink(): {}", lt);
+		
+        try {
+            // get source port vertex
+         	String dpid = HexString.toHexString(lt.getSrc());
+         	short port = lt.getSrcPort();
+         	vportSrc = dbop.searchPort(dpid, port);
+            
+            // get dst port vertex
+         	dpid = HexString.toHexString(lt.getDst());
+         	port = lt.getDstPort();
+         	vportDst = dbop.searchPort(dpid, port);
+     		// FIXME: This needs to remove all edges
+         	
+         	if (vportSrc != null && vportDst != null) {
+
+   /*      		for (Edge e : vportSrc.asVertex().getEdges(Direction.OUT)) {
+         			log.debug("deleteLink(): {} in {} out {}", 
+         					new Object[]{e.getLabel(), e.getVertex(Direction.IN), e.getVertex(Direction.OUT)});
+         			if (e.getLabel().equals("link") && e.getVertex(Direction.IN).equals(vportDst)) {
+         				graph.removeEdge(e);
+         				count++;
+         			}
+         		}*/
+         		vportSrc.removeLink(vportDst);
+        		dbop.commit();
+            	log.debug("deleteLink(): deleted edges src {} dst {}", new Object[]{
+            			lt, vportSrc, vportDst});
+            	
+            } else {
+            	log.error("deleteLink(): failed invalid vertices {} src {} dst {}", new Object[]{lt, vportSrc, vportDst});
+            	dbop.rollback();
+            }
+         	
+        } catch (TitanException e) {
+            /*
+             * retry till we succeed?
+             */
+        	log.error("deleteLink(): titan exception {} {}", new Object[]{lt, e.toString()});
+        	dbop.rollback();
+        	e.printStackTrace();
+        }
+	}
+
+	// TODO: Fix me
+	@Override
+	public List<Link> getLinks(Long dpid, short port) {
+		IPortObject vportSrc, vportDst;
+    	List<Link> links = null;
+    	Link lt;
+    	
+		vportSrc = dbop.searchPort(HexString.toHexString(dpid), port);
+		if (vportSrc != null) {
+			
+     		for (Edge e : vportSrc.asVertex().getEdges(Direction.OUT)) {
+     			if (e.getLabel().equals("link")) {
+     				break;
+     			}
+     		}
+		}
+     	return null;
+	}
+	
+	@Override
+	public void init(String conf) {
+		//TODO extract the DB location from properties
+		this.dbop = new GraphDBOperation(GraphDBConnection.getInstance(conf));
+	}
+
+	@Override
+	public void deleteLinksOnPort(Long dpid, short port) {
+		// TODO Auto-generated method stub
+		
+	}
+
+	@Override
+	public List<Link> getLinks(String dpid) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	public List<Link> getActiveLinks() {
+		Iterable<ISwitchObject> switches = dbop.getActiveSwitches();
+
+		List<Link> links = new ArrayList<Link>(); 
+		for (ISwitchObject sw : switches) {
+			GremlinPipeline<Vertex, Link> pipe = new GremlinPipeline<Vertex, Link>();
+			ExtractLink extractor = new ExtractLink();
+
+			pipe.start(sw.asVertex());
+			pipe.enablePath(true);
+			pipe.out("on").out("link").in("on").path().step(extractor);
+					
+			while (pipe.hasNext() ) {
+				Link l = pipe.next();
+				links.add(l);
+			}
+						
+		}
+		return links;
+	}
+	
+	// FIXME Scope changed to public to allow access from TopoLinkServiceImpl. Move class definition to appropriate place.
+	static public class ExtractLink implements PipeFunction<PathPipe<Vertex>, Link> {
+	
+		@Override
+		public Link compute(PathPipe<Vertex> pipe ) {
+			// TODO Auto-generated method stub
+			long s_dpid = 0;
+			long d_dpid = 0;
+			short s_port = 0;
+			short d_port = 0;
+			List<Vertex> V = new ArrayList<Vertex>();
+			V = pipe.next();
+			Vertex src_sw = V.get(0);
+			Vertex dest_sw = V.get(3);
+			Vertex src_port = V.get(1);
+			Vertex dest_port = V.get(2);
+			s_dpid = HexString.toLong((String) src_sw.getProperty("dpid"));
+			d_dpid = HexString.toLong((String) dest_sw.getProperty("dpid"));
+			s_port = (Short) src_port.getProperty("number");
+			d_port = (Short) dest_port.getProperty("number");
+			
+			Link l = new Link(s_dpid,s_port,d_dpid,d_port);
+			
+			return l;
+		}
+	}
+	
+	public void finalize() {
+		close();
+	}
+
+	@Override
+	public void close() {
+		// TODO Auto-generated method stub
+//		graph.shutdown();		
+	}
+
+
+}