diff --git a/src/main/java/net/onrc/onos/datagrid/HazelcastDatagrid.java b/src/main/java/net/onrc/onos/datagrid/HazelcastDatagrid.java
index 37ada35..cfc6182 100644
--- a/src/main/java/net/onrc/onos/datagrid/HazelcastDatagrid.java
+++ b/src/main/java/net/onrc/onos/datagrid/HazelcastDatagrid.java
@@ -19,6 +19,7 @@
 import net.floodlightcontroller.core.module.IFloodlightService;
 
 import net.onrc.onos.ofcontroller.flowmanager.IFlowService;
+import net.onrc.onos.ofcontroller.topology.TopologyElement;
 import net.onrc.onos.ofcontroller.util.FlowId;
 import net.onrc.onos.ofcontroller.util.FlowPath;
 import net.onrc.onos.ofcontroller.util.serializers.KryoFactory;
@@ -59,6 +60,12 @@
     private MapFlowListener mapFlowListener = null;
     private String mapFlowListenerId = null;
 
+    // State related to the Network Topology map
+    protected static final String mapTopologyName = "mapTopology";
+    private IMap<String, byte[]> mapTopology = null;
+    private MapTopologyListener mapTopologyListener = null;
+    private String mapTopologyListenerId = null;
+
     /**
      * Class for receiving notifications for Flow state.
      *
@@ -135,6 +142,84 @@
     }
 
     /**
+     * Class for receiving notifications for Network Topology state.
+     *
+     * The datagrid map is:
+     *  - Key: TopologyElement ID (String)
+     *  - Value: Serialized TopologyElement (byte[])
+     */
+    class MapTopologyListener implements EntryListener<String, byte[]> {
+	/**
+	 * Receive a notification that an entry is added.
+	 *
+	 * @param event the notification event for the entry.
+	 */
+	public void entryAdded(EntryEvent event) {
+	    String keyString = (String)event.getKey();
+	    byte[] valueBytes = (byte[])event.getValue();
+
+	    //
+	    // Decode the value and deliver the notification
+	    //
+	    Kryo kryo = kryoFactory.newKryo();
+	    Input input = new Input(valueBytes);
+	    TopologyElement topologyElement =
+		kryo.readObject(input, TopologyElement.class);
+	    kryoFactory.deleteKryo(kryo);
+	    flowService.notificationRecvTopologyElementAdded(topologyElement);
+	}
+
+	/**
+	 * Receive a notification that an entry is removed.
+	 *
+	 * @param event the notification event for the entry.
+	 */
+	public void entryRemoved(EntryEvent event) {
+	    String keyString = (String)event.getKey();
+	    byte[] valueBytes = (byte[])event.getValue();
+
+	    //
+	    // Decode the value and deliver the notification
+	    //
+	    Kryo kryo = kryoFactory.newKryo();
+	    Input input = new Input(valueBytes);
+	    TopologyElement topologyElement =
+		kryo.readObject(input, TopologyElement.class);
+	    kryoFactory.deleteKryo(kryo);
+	    flowService.notificationRecvTopologyElementRemoved(topologyElement);
+	}
+
+	/**
+	 * Receive a notification that an entry is updated.
+	 *
+	 * @param event the notification event for the entry.
+	 */
+	public void entryUpdated(EntryEvent event) {
+	    String keyString = (String)event.getKey();
+	    byte[] valueBytes = (byte[])event.getValue();
+
+	    //
+	    // Decode the value and deliver the notification
+	    //
+	    Kryo kryo = kryoFactory.newKryo();
+	    Input input = new Input(valueBytes);
+	    TopologyElement topologyElement =
+		kryo.readObject(input, TopologyElement.class);
+	    kryoFactory.deleteKryo(kryo);
+	    flowService.notificationRecvTopologyElementUpdated(topologyElement);
+	}
+
+	/**
+	 * Receive a notification that an entry is evicted.
+	 *
+	 * @param event the notification event for the entry.
+	 */
+	public void entryEvicted(EntryEvent event) {
+	    // NOTE: We don't use eviction for this map
+	}
+    }
+
+    /**
      * Initialize the Hazelcast Datagrid operation.
      *
      * @param conf the configuration filename.
@@ -256,9 +341,16 @@
     @Override
     public void registerFlowService(IFlowService flowService) {
 	this.flowService = flowService;
+
+	// Initialize the Flow-related map state
 	mapFlowListener = new MapFlowListener();
 	mapFlow = hazelcastInstance.getMap(mapFlowName);
 	mapFlowListenerId = mapFlow.addEntryListener(mapFlowListener, true);
+
+	// Initialize the Topology-related map state
+	mapTopologyListener = new MapTopologyListener();
+	mapTopology = hazelcastInstance.getMap(mapTopologyName);
+	mapTopologyListenerId = mapTopology.addEntryListener(mapTopologyListener, true);
     }
 
     /**
@@ -270,9 +362,16 @@
      */
     @Override
     public void deregisterFlowService(IFlowService flowService) {
+	// Clear the Flow-related map state
 	mapFlow.removeEntryListener(mapFlowListenerId);
 	mapFlow = null;
 	mapFlowListener = null;
+
+	// Clear the Topology-related map state
+	mapTopology.removeEntryListener(mapTopologyListenerId);
+	mapTopology = null;
+	mapTopologyListener = null;
+
 	this.flowService = null;
     }
 
@@ -370,4 +469,101 @@
 	    mapFlow.removeAsync(key);
 	}
     }
+
+    /**
+     * Get all Topology Elements that are currently in the datagrid.
+     *
+     * @return all Topology Elements that are currently in the datagrid.
+     */
+    @Override
+    public Collection<TopologyElement> getAllTopologyElements() {
+	Collection<TopologyElement> allTopologyElements =
+	    new LinkedList<TopologyElement>();
+
+	//
+	// Get all current entries
+	//
+	Collection<byte[]> values = mapTopology.values();
+	Kryo kryo = kryoFactory.newKryo();
+	for (byte[] valueBytes : values) {
+	    //
+	    // Decode the value
+	    //
+	    Input input = new Input(valueBytes);
+	    TopologyElement topologyElement =
+		kryo.readObject(input, TopologyElement.class);
+	    allTopologyElements.add(topologyElement);
+	}
+	kryoFactory.deleteKryo(kryo);
+
+	return allTopologyElements;
+    }
+
+    /**
+     * Send a notification that a Topology Element is added.
+     *
+     * @param topologyElement the Topology Element that is added.
+     */
+    @Override
+    public void notificationSendTopologyElementAdded(TopologyElement topologyElement) {
+	//
+	// Encode the value
+	//
+	byte[] buffer = new byte[MAX_BUFFER_SIZE];
+	Kryo kryo = kryoFactory.newKryo();
+	Output output = new Output(buffer, -1);
+	kryo.writeObject(output, topologyElement);
+	byte[] valueBytes = output.toBytes();
+	kryoFactory.deleteKryo(kryo);
+
+	//
+	// Put the entry:
+	//  - Key : TopologyElement ID (String)
+	//  - Value : Serialized TopologyElement (byte[])
+	//
+	mapTopology.putAsync(topologyElement.elementId(), valueBytes);
+    }
+
+    /**
+     * Send a notification that a Topology Element is removed.
+     *
+     * @param topologyElement the Topology Element that is removed.
+     */
+    @Override
+    public void notificationSendTopologyElementRemoved(TopologyElement topologyElement) {
+	//
+	// Remove the entry:
+	//  - Key : TopologyElement ID (String)
+	//  - Value : Serialized TopologyElement (byte[])
+	//
+	mapTopology.removeAsync(topologyElement.elementId());
+    }
+
+    /**
+     * Send a notification that a Topology Element is updated.
+     *
+     * @param topologyElement the Topology Element that is updated.
+     */
+    @Override
+    public void notificationSendTopologyElementUpdated(TopologyElement topologyElement) {
+	// NOTE: Adding an entry with an existing key automatically updates it
+	notificationSendTopologyElementAdded(topologyElement);
+    }
+
+    /**
+     * Send a notification that all Topology Elements are removed.
+     */
+    @Override
+    public void notificationSendAllTopologyElementsRemoved() {
+	//
+	// Remove all entries
+	// NOTE: We remove the entries one-by-one so the per-entry
+	// notifications will be delivered.
+	//
+	// mapTopology.clear();
+	Set<String> keySet = mapTopology.keySet();
+	for (String key : keySet) {
+	    mapTopology.removeAsync(key);
+	}
+    }
 }
diff --git a/src/main/java/net/onrc/onos/datagrid/IDatagridService.java b/src/main/java/net/onrc/onos/datagrid/IDatagridService.java
index 498f58b..bf8e41f 100644
--- a/src/main/java/net/onrc/onos/datagrid/IDatagridService.java
+++ b/src/main/java/net/onrc/onos/datagrid/IDatagridService.java
@@ -5,6 +5,7 @@
 import net.floodlightcontroller.core.module.IFloodlightService;
 
 import net.onrc.onos.ofcontroller.flowmanager.IFlowService;
+import net.onrc.onos.ofcontroller.topology.TopologyElement;
 import net.onrc.onos.ofcontroller.util.FlowId;
 import net.onrc.onos.ofcontroller.util.FlowPath;
 
@@ -62,4 +63,37 @@
      * Send a notification that all Flows are removed.
      */
     void notificationSendAllFlowsRemoved();
+
+    /**
+     * Get all Topology Elements that are currently in the datagrid.
+     *
+     * @return all Topology Elements that are currently in the datagrid.
+     */
+    Collection<TopologyElement> getAllTopologyElements();
+
+    /**
+     * Send a notification that a Topology Element is added.
+     *
+     * @param topologyElement the Topology Element that is added.
+     */
+    void notificationSendTopologyElementAdded(TopologyElement topologyElement);
+
+    /**
+     * Send a notification that a Topology Element is removed.
+     *
+     * @param topologyElement the Topology Element that is removed.
+     */
+    void notificationSendTopologyElementRemoved(TopologyElement topologyElement);
+
+    /**
+     * Send a notification that a Topology Element is updated.
+     *
+     * @param topologyElement the Topology Element that is updated.
+     */
+    void notificationSendTopologyElementUpdated(TopologyElement topologyElement);
+
+    /**
+     * Send a notification that all Topology Elements are removed.
+     */
+    void notificationSendAllTopologyElementsRemoved();
 }
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 012f333..44607a9 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowManager.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/FlowManager.java
@@ -31,6 +31,7 @@
 import net.onrc.onos.ofcontroller.flowmanager.web.FlowWebRoutable;
 import net.onrc.onos.ofcontroller.topology.ITopologyNetService;
 import net.onrc.onos.ofcontroller.topology.Topology;
+import net.onrc.onos.ofcontroller.topology.TopologyElement;
 import net.onrc.onos.ofcontroller.util.*;
 
 import org.openflow.protocol.OFType;
@@ -76,6 +77,10 @@
     protected BlockingQueue<EventEntry<FlowPath>> flowPathEvents =
 	new LinkedBlockingQueue<EventEntry<FlowPath>>();
 
+    // The queue with Topology Element updates
+    protected BlockingQueue<EventEntry<TopologyElement>> topologyEvents =
+	new LinkedBlockingQueue<EventEntry<TopologyElement>>();
+
     /**
      * Periodic task for reading the Flow Entries and pushing changes
      * into the switches.
@@ -494,8 +499,19 @@
 	// Initialize the Flow Entry ID generator
 	nextFlowEntryIdPrefix = randomGenerator.nextInt();
 
-	// Register with the Datagrid Service and obtain the initial state
+	// Register with the Datagrid Service
 	datagridService.registerFlowService(this);
+
+	// Obtain the initial Topology state
+	Collection<TopologyElement> topologyElements =
+	    datagridService.getAllTopologyElements();
+	for (TopologyElement topologyElement : topologyElements) {
+	    EventEntry<TopologyElement> eventEntry =
+		new EventEntry<TopologyElement>(EventEntry.Type.ENTRY_ADD, topologyElement);
+	    topologyEvents.add(eventEntry);
+	}
+
+	// Obtain the initial Flow state
 	Collection<FlowPath> flowPaths = datagridService.getAllFlows();
 	for (FlowPath flowPath : flowPaths) {
 	    EventEntry<FlowPath> eventEntry =
@@ -864,4 +880,34 @@
     public void notificationRecvFlowUpdated(FlowPath flowPath) {
 	// TODO
     }
+
+    /**
+     * Receive a notification that a Topology Element is added.
+     *
+     * @param topologyElement the Topology Element that is added.
+     */
+    @Override
+    public void notificationRecvTopologyElementAdded(TopologyElement topologyElement) {
+	// TODO
+    }
+
+    /**
+     * Receive a notification that a Topology Element is removed.
+     *
+     * @param topologyElement the Topology Element that is removed.
+     */
+    @Override
+    public void notificationRecvTopologyElementRemoved(TopologyElement topologyElement) {
+	// TODO
+    }
+
+    /**
+     * Receive a notification that a Topology Element is updated.
+     *
+     * @param topologyElement the Topology Element that is updated.
+     */
+    @Override
+    public void notificationRecvTopologyElementUpdated(TopologyElement topologyElement) {
+	// TODO
+    }
 }
diff --git a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/IFlowService.java b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/IFlowService.java
index 8c908cf..a15f56c 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/flowmanager/IFlowService.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/flowmanager/IFlowService.java
@@ -4,6 +4,7 @@
 
 import net.floodlightcontroller.core.module.IFloodlightService;
 import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IFlowPath;
+import net.onrc.onos.ofcontroller.topology.TopologyElement;
 import net.onrc.onos.ofcontroller.util.CallerId;
 import net.onrc.onos.ofcontroller.util.DataPathEndpoints;
 import net.onrc.onos.ofcontroller.util.FlowId;
@@ -136,4 +137,25 @@
      * @param flowPath the flow that is updated.
      */
     void notificationRecvFlowUpdated(FlowPath flowPath);
+
+    /**
+     * Receive a notification that a Topology Element is added.
+     *
+     * @param topologyElement the Topology Element that is added.
+     */
+    void notificationRecvTopologyElementAdded(TopologyElement topologyElement);
+
+    /**
+     * Receive a notification that a Topology Element is removed.
+     *
+     * @param topologyElement the Topology Element that is removed.
+     */
+    void notificationRecvTopologyElementRemoved(TopologyElement topologyElement);
+
+    /**
+     * Receive a notification that a Topology Element is updated.
+     *
+     * @param topologyElement the Topology Element that is updated.
+     */
+    void notificationRecvTopologyElementUpdated(TopologyElement topologyElement);
 }
diff --git a/src/main/java/net/onrc/onos/ofcontroller/topology/TopologyElement.java b/src/main/java/net/onrc/onos/ofcontroller/topology/TopologyElement.java
new file mode 100644
index 0000000..6809125
--- /dev/null
+++ b/src/main/java/net/onrc/onos/ofcontroller/topology/TopologyElement.java
@@ -0,0 +1,90 @@
+package net.onrc.onos.ofcontroller.topology;
+
+/**
+ * Class for storing information about a Topology Element: Switch, Port or
+ * Link.
+ */
+public class TopologyElement {
+    /**
+     * The Element Type.
+     */
+    enum Type {
+	ELEMENT_SWITCH,		// Network Switch
+	ELEMENT_PORT,		// Switch Port
+	ELEMENT_LINK		// Unidirectional Link between Switch Ports
+    }
+
+    private Type elementType;		// The element type
+    private long fromSwitchDpid = 0;	// The Switch DPID
+    private int fromSwitchPort = 0;	// The Switch Port
+    private long toSwitchDpid = 0;	// The Neighbor Switch DPID
+    private int toSwitchPort = 0;	// The Neighbor Switch Port
+
+    /**
+     * Constructor to create a Topology Element for a Switch.
+     *
+     * @param switchDpid the Switch DPID.
+     */
+    public TopologyElement(long switchDpid) {
+	this.elementType = Type.ELEMENT_SWITCH;
+	this.fromSwitchDpid = switchDpid;
+    }
+
+    /**
+     * Constructor to create a Topology Element for a Switch Port.
+     *
+     * @param switchDpid the Switch DPID.
+     * @param switchPort the Switch Port.
+     */
+    public TopologyElement(long switchDpid, int switchPort) {
+	this.elementType = Type.ELEMENT_PORT;
+	this.fromSwitchDpid = switchDpid;
+	this.fromSwitchPort = switchPort;
+    }
+
+    /**
+     * Constructor to create a Topology Element for an unidirectional Link
+     * between Switch Ports.
+     *
+     * @param fromSwitchDpid the Switch DPID the Link begins from.
+     * @param fromSwitchPort the Switch Port the Link begins from.
+     * @param toSwitchDpid the Switch DPID the Link ends to.
+     * @param toSwitchPort the Switch Port the Link ends to.
+     */
+    public TopologyElement(long fromSwitchDpid, int fromSwitchPort,
+			   long toSwitchDpid, int toSwitchPort) {
+	this.elementType = Type.ELEMENT_LINK;
+	this.fromSwitchDpid = fromSwitchDpid;
+	this.fromSwitchPort = fromSwitchPort;
+	this.toSwitchDpid = toSwitchDpid;
+	this.toSwitchPort = toSwitchPort;
+    }
+
+    /**
+     * Get the Topology Element ID.
+     *
+     * The Topology Element ID has the following format:
+     *   - Switch: "Switch=<Dpid>"
+     *     Example: "Switch=00:00:00:00:00:00:00:01"
+     *   - Switch Port: "Port=<Dpid>/<PortId>"
+     *     Example: "Port=00:00:00:00:00:00:00:01/1"
+     *   - Link: "Link=<FromDpid>/<FromPortId>/<ToDpid>/<ToPortId>"
+     *     Example: "Link=00:00:00:00:00:00:00:01/1/00:00:00:00:00:00:00:02/1"
+     *
+     * @return the Topology Element ID.
+     */
+    public String elementId() {
+	switch (elementType) {
+	case ELEMENT_SWITCH:
+	    return "Switch=" + fromSwitchDpid;
+	case ELEMENT_PORT:
+	    return "Port=" + fromSwitchDpid + "/" + fromSwitchPort;
+	case ELEMENT_LINK:
+	    return "Link=" + fromSwitchDpid + "/" + fromSwitchPort +
+		toSwitchDpid + "/" + toSwitchPort;
+	}
+
+	assert(false);
+	return null;
+    }
+}
diff --git a/src/main/java/net/onrc/onos/ofcontroller/util/serializers/KryoFactory.java b/src/main/java/net/onrc/onos/ofcontroller/util/serializers/KryoFactory.java
index 405a3ee..e0da7a8 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/util/serializers/KryoFactory.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/util/serializers/KryoFactory.java
@@ -1,11 +1,14 @@
 package net.onrc.onos.ofcontroller.util.serializers;
 
 import java.util.ArrayList;
+
 import com.esotericsoftware.kryo2.Kryo;
-import net.onrc.onos.ofcontroller.util.*;
 
 import net.floodlightcontroller.util.MACAddress;
 
+import net.onrc.onos.ofcontroller.util.*;
+import net.onrc.onos.ofcontroller.topology.TopologyElement;
+
 /**
  * Class factory for allocating Kryo instances for
  * serialization/deserialization of classes.
@@ -81,6 +84,8 @@
 	// kryo.setReferences(false);
 	//
 	kryo.register(ArrayList.class);
+
+	// FlowPath and related classes
 	kryo.register(CallerId.class);
 	kryo.register(DataPath.class);
 	kryo.register(DataPathEndpoints.class);
@@ -117,6 +122,9 @@
 	kryo.register(Switch.class);
 	kryo.register(SwitchPort.class);
 
+	// Topology-related classes
+	kryo.register(TopologyElement.class);
+
 	return kryo;
     }
 }