diff --git a/src/main/java/net/onrc/onos/core/topology/MastershipEvent.java b/src/main/java/net/onrc/onos/core/topology/MastershipEvent.java
new file mode 100644
index 0000000..01323ba
--- /dev/null
+++ b/src/main/java/net/onrc/onos/core/topology/MastershipEvent.java
@@ -0,0 +1,145 @@
+package net.onrc.onos.core.topology;
+
+import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
+import java.util.Objects;
+
+import net.floodlightcontroller.core.IFloodlightProviderService.Role;
+import net.onrc.onos.core.topology.web.serializers.MastershipEventSerializer;
+import net.onrc.onos.core.util.Dpid;
+
+import org.apache.commons.lang.Validate;
+import org.codehaus.jackson.map.annotate.JsonSerialize;
+
+/**
+ * Self-contained Switch Mastership event Object.
+ * <p/>
+ * TODO: Rename to match what it is. (Switch/Port/Link/Host)Snapshot?
+ * FIXME: Current implementation directly use this object as
+ *        Replication message, but should be sending update operation info.
+ */
+@JsonSerialize(using = MastershipEventSerializer.class)
+public class MastershipEvent extends TopologyElement<MastershipEvent> {
+
+    private final Dpid dpid;
+    private final String onosInstanceId;
+    private final Role role;
+
+    /**
+     * Default constructor for Serializer to use.
+     */
+    @Deprecated
+    protected MastershipEvent() {
+        dpid = null;
+        onosInstanceId = null;
+        role = Role.SLAVE;              // Default role is SLAVE
+    }
+
+    /**
+     * Creates the Switch Mastership object.
+     *
+     * @param dpid the Switch DPID
+     * @param onosInstanceId the ONOS Instance ID
+     * @param role the ONOS instance role for the switch.
+     */
+    public MastershipEvent(Dpid dpid, String onosInstanceId, Role role) {
+        Validate.notNull(dpid);
+        Validate.notNull(onosInstanceId);
+
+        this.dpid = dpid;
+        this.onosInstanceId = onosInstanceId;
+        this.role = role;
+    }
+
+    /**
+     * Creates an unfrozen copy of given Object.
+     *
+     * @param original to make copy of.
+     */
+    public MastershipEvent(MastershipEvent original) {
+        super(original);
+        this.dpid = original.dpid;
+        this.onosInstanceId = original.onosInstanceId;
+        this.role = original.role;
+    }
+
+    /**
+     * Gets the Switch DPID.
+     *
+     * @return the Switch DPID.
+     */
+    public Dpid getDpid() {
+        return dpid;
+    }
+
+    /**
+     * Gets the ONOS Instance ID.
+     *
+     * @return the ONOS Instance ID.
+     */
+    public String getOnosInstanceId() {
+        return onosInstanceId;
+    }
+
+    /**
+     * Gets the ONOS Controller Role for the Switch.
+     *
+     * @return the ONOS Controller Role for the Switch.
+     */
+    public Role getRole() {
+        return role;
+    }
+
+    @Override
+    public String toString() {
+        return "[MastershipEvent " + getDpid() + "@" + getOnosInstanceId() +
+            "->" + getRole() + "]";
+    }
+
+    public byte[] getID() {
+        String keyStr = "M" + getDpid() + "@" + getOnosInstanceId();
+        return keyStr.getBytes(StandardCharsets.UTF_8);
+    }
+
+    public ByteBuffer getIDasByteBuffer() {
+        ByteBuffer buf = ByteBuffer.wrap(getID());
+        return buf;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(dpid, onosInstanceId);
+    }
+
+    /**
+     * Compares two MastershipEvent objects.
+     * MastershipEvent objects are equal if they have same DPID and same
+     * ONOS Instance ID.
+     *
+     * @param obj another object to compare to this
+     * @returns true if equal, false otherwise false.
+     */
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+
+        if (obj == null) {
+            return false;
+        }
+
+        if (getClass() != obj.getClass()) {
+            return false;
+        }
+
+        // compare attributes
+        if (!super.equals(obj)) {
+            return false;
+        }
+
+        MastershipEvent other = (MastershipEvent) obj;
+        return dpid.equals(other.dpid) &&
+            onosInstanceId.equals(other.onosInstanceId);
+    }
+}
diff --git a/src/main/java/net/onrc/onos/core/topology/TopologyDiscoveryInterface.java b/src/main/java/net/onrc/onos/core/topology/TopologyDiscoveryInterface.java
index d9c5c38..289ed05 100644
--- a/src/main/java/net/onrc/onos/core/topology/TopologyDiscoveryInterface.java
+++ b/src/main/java/net/onrc/onos/core/topology/TopologyDiscoveryInterface.java
@@ -54,14 +54,28 @@
     /**
      * Host discovered event.
      *
-     * @param hostEvent the device event.
+     * @param hostEvent the host event.
      */
     public void putHostDiscoveryEvent(HostEvent hostEvent);
 
     /**
      * Host removed event.
      *
-     * @param hostEvent the device event.
+     * @param hostEvent the host event.
      */
     public void removeHostDiscoveryEvent(HostEvent hostEvent);
+
+    /**
+     * Switch Mastership updated event.
+     *
+     * @param mastershipEvent the mastership event.
+     */
+    public void putSwitchMastershipEvent(MastershipEvent mastershipEvent);
+
+    /**
+     * Switch Mastership removed event.
+     *
+     * @param mastershipEvent the mastership event.
+     */
+    public void removeSwitchMastershipEvent(MastershipEvent mastershipEvent);
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/TopologyElement.java b/src/main/java/net/onrc/onos/core/topology/TopologyElement.java
index f70e7f5..bb32958 100644
--- a/src/main/java/net/onrc/onos/core/topology/TopologyElement.java
+++ b/src/main/java/net/onrc/onos/core/topology/TopologyElement.java
@@ -26,13 +26,20 @@
      */
     public static final String TYPE = "type";
     /**
-     * Attribute "type" value representing that the object belongs to Packet layer.
+     * Attribute "type" value representing that the object belongs to Packet
+     * layer.
      */
     public static final String TYPE_PACKET_LAYER = "packet";
     /**
-     * Attribute "type" value representing that the object belongs to Optical layer.
+     * Attribute "type" value representing that the object belongs to Optical
+     * layer.
      */
     public static final String TYPE_OPTICAL_LAYER = "optical";
+    /**
+     * Attribute "type" value representing that the object belongs to all
+     * layers.
+     */
+    public static final String TYPE_ALL_LAYERS = "AllLayers";
 
     public static final String ELEMENT_CONFIG_STATE = "ConfigState";
 
diff --git a/src/main/java/net/onrc/onos/core/topology/TopologyEvent.java b/src/main/java/net/onrc/onos/core/topology/TopologyEvent.java
index 81e261d..cdae99c 100644
--- a/src/main/java/net/onrc/onos/core/topology/TopologyEvent.java
+++ b/src/main/java/net/onrc/onos/core/topology/TopologyEvent.java
@@ -7,14 +7,15 @@
  * Self-contained Topology event Object
  * <p/>
  * TODO: For now the topology event contains one of the following events:
- * Switch, Port, Link, Host. In the future it will contain multiple events
- * in a single transaction.
+ * Switch, Port, Link, Host, Switch Mastership. In the future it will contain
+ * multiple events in a single transaction.
  */
 public class TopologyEvent {
-    SwitchEvent switchEvent = null;        // Set for Switch event
-    PortEvent portEvent = null;            // Set for Port event
-    LinkEvent linkEvent = null;            // Set for Link event
-    HostEvent hostEvent = null;        // Set for Host event
+    SwitchEvent switchEvent = null;             // Set for Switch event
+    PortEvent portEvent = null;                 // Set for Port event
+    LinkEvent linkEvent = null;                 // Set for Link event
+    HostEvent hostEvent = null;                 // Set for Host event
+    MastershipEvent mastershipEvent = null;     // Set for Mastership event
 
     /**
      * Default constructor.
@@ -59,6 +60,15 @@
     }
 
     /**
+     * Constructor for given Switch Mastership event.
+     *
+     * @param mastershipEvent the Switch Mastership event to use.
+     */
+    TopologyEvent(MastershipEvent mastershipEvent) {
+        this.mastershipEvent = mastershipEvent;
+    }
+
+    /**
      * Check if all events contained are equal.
      *
      * @param obj TopologyEvent to compare against
@@ -81,12 +91,14 @@
         return Objects.equals(switchEvent, other.switchEvent) &&
                 Objects.equals(portEvent, other.portEvent) &&
                 Objects.equals(linkEvent, other.linkEvent) &&
-                Objects.equals(hostEvent, other.hostEvent);
+                Objects.equals(hostEvent, other.hostEvent) &&
+                Objects.equals(mastershipEvent, other.mastershipEvent);
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(switchEvent, portEvent, linkEvent, hostEvent);
+        return Objects.hash(switchEvent, portEvent, linkEvent, hostEvent,
+                            mastershipEvent);
     }
 
     /**
@@ -108,6 +120,9 @@
         if (hostEvent != null) {
             return hostEvent.toString();
         }
+        if (mastershipEvent != null) {
+            return mastershipEvent.toString();
+        }
         return "[Empty TopologyEvent]";
     }
 
@@ -129,6 +144,9 @@
         if (hostEvent != null) {
             return hostEvent.getID();
         }
+        if (mastershipEvent != null) {
+            return mastershipEvent.getID();
+        }
         throw new IllegalStateException("Invalid TopologyEvent ID");
     }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/TopologyManager.java b/src/main/java/net/onrc/onos/core/topology/TopologyManager.java
index b12bc0f..e733c68 100644
--- a/src/main/java/net/onrc/onos/core/topology/TopologyManager.java
+++ b/src/main/java/net/onrc/onos/core/topology/TopologyManager.java
@@ -263,6 +263,10 @@
             Map<ByteBuffer, LinkEvent> removedLinkEvents = new HashMap<>();
             Map<ByteBuffer, HostEvent> addedHostEvents = new HashMap<>();
             Map<ByteBuffer, HostEvent> removedHostEvents = new HashMap<>();
+            Map<ByteBuffer, MastershipEvent> addedMastershipEvents =
+                new HashMap<>();
+            Map<ByteBuffer, MastershipEvent> removedMastershipEvents =
+                new HashMap<>();
 
             //
             // Classify and suppress matching events
@@ -273,6 +277,7 @@
                 PortEvent portEvent = topologyEvent.portEvent;
                 LinkEvent linkEvent = topologyEvent.linkEvent;
                 HostEvent hostEvent = topologyEvent.hostEvent;
+                MastershipEvent mastershipEvent = topologyEvent.mastershipEvent;
 
                 //
                 // Extract the events
@@ -306,6 +311,11 @@
                             removedHostEvents.remove(id);
                             reorderedAddedHostEvents.remove(id);
                         }
+                        if (mastershipEvent != null) {
+                            ByteBuffer id = mastershipEvent.getIDasByteBuffer();
+                            addedMastershipEvents.put(id, mastershipEvent);
+                            removedMastershipEvents.remove(id);
+                        }
                         break;
                     case ENTRY_REMOVE:
                         log.debug("Topology event ENTRY_REMOVE: {}", topologyEvent);
@@ -333,6 +343,11 @@
                             removedHostEvents.put(id, hostEvent);
                             reorderedAddedHostEvents.remove(id);
                         }
+                        if (mastershipEvent != null) {
+                            ByteBuffer id = mastershipEvent.getIDasByteBuffer();
+                            addedMastershipEvents.remove(id);
+                            removedMastershipEvents.put(id, mastershipEvent);
+                        }
                         break;
                     default:
                         log.error("Unknown topology event {}",
@@ -350,8 +365,15 @@
                 // Apply the classified events.
                 //
                 // Apply the "add" events in the proper order:
-                //   switch, port, link, host
+                //   mastership, switch, port, link, host
                 //
+                // TODO: Currently, the Mastership events are not used,
+                // so their processing ordering is not important (undefined).
+                //
+                for (MastershipEvent mastershipEvent :
+                         addedMastershipEvents.values()) {
+                    processAddedMastershipEvent(mastershipEvent);
+                }
                 for (SwitchEvent switchEvent : addedSwitchEvents.values()) {
                     addSwitch(switchEvent);
                 }
@@ -366,7 +388,7 @@
                 }
                 //
                 // Apply the "remove" events in the reverse order:
-                //   host, link, port, switch
+                //   host, link, port, switch, mastership
                 //
                 for (HostEvent hostEvent : removedHostEvents.values()) {
                     removeHost(hostEvent);
@@ -380,6 +402,10 @@
                 for (SwitchEvent switchEvent : removedSwitchEvents.values()) {
                     removeSwitch(switchEvent);
                 }
+                for (MastershipEvent mastershipEvent :
+                         removedMastershipEvents.values()) {
+                    processRemovedMastershipEvent(mastershipEvent);
+                }
 
                 //
                 // Apply reordered events
@@ -888,6 +914,29 @@
     //
 
     /**
+     * Mastership updated event.
+     *
+     * @param mastershipEvent the mastership event.
+     */
+    @Override
+    public void putSwitchMastershipEvent(MastershipEvent mastershipEvent) {
+        // Send out notification
+        TopologyEvent topologyEvent = new TopologyEvent(mastershipEvent);
+        eventChannel.addEntry(topologyEvent.getID(), topologyEvent);
+    }
+
+    /**
+     * Mastership removed event.
+     *
+     * @param mastershipEvent the mastership event.
+     */
+    @Override
+    public void removeSwitchMastershipEvent(MastershipEvent mastershipEvent) {
+        // Send out notification
+        eventChannel.removeEntry(mastershipEvent.getID());
+    }
+
+    /**
      * Adds a switch to the topology replica.
      *
      * @param switchEvent the SwitchEvent with the switch to add.
@@ -1272,6 +1321,30 @@
     }
 
     /**
+     * Processes added Switch Mastership event.
+     *
+     * @param mastershipEvent the MastershipEvent to process.
+     */
+    @GuardedBy("topology.writeLock")
+    private void processAddedMastershipEvent(MastershipEvent mastershipEvent) {
+        log.debug("Processing added Mastership event {}",
+                  mastershipEvent);
+        // TODO: Not implemented/used yet.
+    }
+
+    /**
+     * Processes removed Switch Mastership event.
+     *
+     * @param mastershipEvent the MastershipEvent to process.
+     */
+    @GuardedBy("topology.writeLock")
+    private void processRemovedMastershipEvent(MastershipEvent mastershipEvent) {
+        log.debug("Processing removed Mastership event {}",
+                  mastershipEvent);
+        // TODO: Not implemented/used yet.
+    }
+
+    /**
      * Read the whole topology from the database.
      *
      * @return a collection of EventEntry-encapsulated Topology Events for
diff --git a/src/main/java/net/onrc/onos/core/topology/TopologyPublisher.java b/src/main/java/net/onrc/onos/core/topology/TopologyPublisher.java
index f11c06d..3b6a5e9 100644
--- a/src/main/java/net/onrc/onos/core/topology/TopologyPublisher.java
+++ b/src/main/java/net/onrc/onos/core/topology/TopologyPublisher.java
@@ -7,6 +7,7 @@
 import java.util.concurrent.TimeUnit;
 
 import net.floodlightcontroller.core.IFloodlightProviderService;
+import net.floodlightcontroller.core.IFloodlightProviderService.Role;
 import net.floodlightcontroller.core.IOFSwitch;
 import net.floodlightcontroller.core.module.FloodlightModuleContext;
 import net.floodlightcontroller.core.module.FloodlightModuleException;
@@ -14,6 +15,7 @@
 import net.floodlightcontroller.core.module.IFloodlightService;
 import net.floodlightcontroller.core.util.SingletonTask;
 import net.floodlightcontroller.threadpool.IThreadPoolService;
+import net.onrc.onos.api.registry.ILocalSwitchMastershipListener;
 import net.onrc.onos.core.hostmanager.Host;
 import net.onrc.onos.core.hostmanager.IHostListener;
 import net.onrc.onos.core.hostmanager.IHostService;
@@ -42,7 +44,8 @@
         IOFSwitchPortListener,
         ILinkDiscoveryListener,
         IFloodlightModule,
-        IHostListener {
+        IHostListener,
+        ILocalSwitchMastershipListener {
     private static final Logger log =
             LoggerFactory.getLogger(TopologyPublisher.class);
 
@@ -331,6 +334,8 @@
         hostService = context.getServiceImpl(IHostService.class);
 
         topologyService = context.getServiceImpl(ITopologyService.class);
+
+        floodlightProvider.addLocalSwitchMastershipListener(this);
     }
 
     @Override
@@ -387,4 +392,35 @@
         event.freeze();
         topologyDiscoveryInterface.removeHostDiscoveryEvent(event);
     }
+
+    @Override
+    public void controllerRoleChanged(Dpid dpid, Role role) {
+        log.debug("Local switch controller mastership role changed: dpid = {} role = {}", dpid, role);
+        MastershipEvent mastershipEvent =
+            new MastershipEvent(dpid, registryService.getControllerId(), role);
+        // FIXME should be merging, with existing attrs, etc..
+        // TODO define attr name as constant somewhere.
+        // TODO populate appropriate attributes.
+        mastershipEvent.createStringAttribute(TopologyElement.TYPE,
+                                              TopologyElement.TYPE_ALL_LAYERS);
+        mastershipEvent.freeze();
+        topologyDiscoveryInterface.putSwitchMastershipEvent(mastershipEvent);
+    }
+
+    @Override
+    public void switchDisconnected(Dpid dpid) {
+        log.debug("Local switch disconnected: dpid = {} role = {}", dpid);
+
+        Role role = Role.SLAVE;         // TODO: Should be Role.UNKNOWN
+
+        MastershipEvent mastershipEvent =
+            new MastershipEvent(dpid, registryService.getControllerId(), role);
+        // FIXME should be merging, with existing attrs, etc..
+        // TODO define attr name as constant somewhere.
+        // TODO populate appropriate attributes.
+        mastershipEvent.createStringAttribute(TopologyElement.TYPE,
+                                              TopologyElement.TYPE_ALL_LAYERS);
+        mastershipEvent.freeze();
+        topologyDiscoveryInterface.removeSwitchMastershipEvent(mastershipEvent);
+    }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/web/serializers/MastershipEventSerializer.java b/src/main/java/net/onrc/onos/core/topology/web/serializers/MastershipEventSerializer.java
new file mode 100644
index 0000000..65198f0
--- /dev/null
+++ b/src/main/java/net/onrc/onos/core/topology/web/serializers/MastershipEventSerializer.java
@@ -0,0 +1,55 @@
+package net.onrc.onos.core.topology.web.serializers;
+
+import net.onrc.onos.core.topology.MastershipEvent;
+import net.onrc.onos.core.topology.TopologyElement;
+
+import org.codehaus.jackson.JsonGenerator;
+import org.codehaus.jackson.map.SerializerProvider;
+import org.codehaus.jackson.map.ser.std.SerializerBase;
+
+import java.io.IOException;
+
+/**
+ * JSON serializer for MastershipEvents.
+ */
+public class MastershipEventSerializer extends SerializerBase<MastershipEvent> {
+
+    /**
+     * Public constructor - just calls its super class constructor.
+     */
+    public MastershipEventSerializer() {
+        super(MastershipEvent.class);
+    }
+
+    /**
+     * Serializes a MastershipEvent object.
+     *
+     * @param mastershipEvent MastershipEvent to serialize
+     * @param jsonGenerator generator to add the serialized object to
+     * @param serializerProvider not used
+     * @throws IOException if the JSON serialization fails
+     */
+    @Override
+    public void serialize(final MastershipEvent mastershipEvent,
+                          final JsonGenerator jsonGenerator,
+                          final SerializerProvider serializerProvider)
+            throws IOException {
+
+        //
+        // TODO: For now, the JSON format of the serialized output should
+        // be same as the JSON format of the corresponding class Mastership
+        // (if such class exists).
+        // In the future, we will use a single serializer.
+        //
+
+        jsonGenerator.writeStartObject();
+        jsonGenerator.writeStringField(TopologyElement.TYPE, mastershipEvent.getType());
+        jsonGenerator.writeStringField("dpid",
+                                       mastershipEvent.getDpid().toString());
+        jsonGenerator.writeStringField("onosInstanceId",
+                                       mastershipEvent.getOnosInstanceId());
+        jsonGenerator.writeStringField("role",
+                                       mastershipEvent.getRole().name());
+        jsonGenerator.writeEndObject();
+    }
+}
diff --git a/src/main/java/net/onrc/onos/core/util/serializers/KryoFactory.java b/src/main/java/net/onrc/onos/core/util/serializers/KryoFactory.java
index d5482ec..47b2349 100644
--- a/src/main/java/net/onrc/onos/core/util/serializers/KryoFactory.java
+++ b/src/main/java/net/onrc/onos/core/util/serializers/KryoFactory.java
@@ -9,6 +9,7 @@
 import java.util.LinkedList;
 import java.util.concurrent.ConcurrentHashMap;
 
+import net.floodlightcontroller.core.IFloodlightProviderService.Role;
 import net.floodlightcontroller.util.MACAddress;
 import net.onrc.onos.apps.proxyarp.ArpCacheNotification;
 import net.onrc.onos.apps.proxyarp.ArpReplyNotification;
@@ -29,6 +30,7 @@
 import net.onrc.onos.core.topology.ConfigState;
 import net.onrc.onos.core.topology.HostEvent;
 import net.onrc.onos.core.topology.LinkEvent;
+import net.onrc.onos.core.topology.MastershipEvent;
 import net.onrc.onos.core.topology.PortEvent;
 import net.onrc.onos.core.topology.SwitchEvent;
 import net.onrc.onos.core.topology.TopologyElement;
@@ -202,7 +204,9 @@
         kryo.register(HostEvent.class);
         kryo.register(LinkedList.class);
         kryo.register(LinkEvent.class);
+        kryo.register(MastershipEvent.class);
         kryo.register(PortEvent.class);
+        kryo.register(Role.class);
         kryo.register(SwitchEvent.class);
         kryo.register(TopologyEvent.class);
         kryo.register(TopologyElement.class);