diff --git a/src/main/java/net/onrc/onos/core/topology/ImmutableTopologySnapshot.java b/src/main/java/net/onrc/onos/core/topology/ImmutableTopologySnapshot.java
index 20b3c48..e115127 100644
--- a/src/main/java/net/onrc/onos/core/topology/ImmutableTopologySnapshot.java
+++ b/src/main/java/net/onrc/onos/core/topology/ImmutableTopologySnapshot.java
@@ -52,7 +52,7 @@
 
     // Mastership info
     // Dpid -> [ (InstanceID, Role) ]
-    private final Map<Dpid, SortedSet<MastershipEvent>> mastership;
+    private final Map<Dpid, SortedSet<MastershipData>> mastership;
 
     // DPID -> Switch
     private final Map<Dpid, SwitchData> switches;
@@ -354,18 +354,18 @@
         /**
          * Puts a mastership change event.
          *
-         * @param master MastershipEvent
+         * @param master MastershipData
          * @return Builder
          */
-        public Builder putSwitchMastershipEvent(MastershipEvent master) {
+        public Builder putSwitchMastershipData(MastershipData master) {
             checkNotNull(master);
 
-            SortedSet<MastershipEvent> candidates
+            SortedSet<MastershipData> candidates
                 = current.mastership.get(master.getDpid());
             if (candidates == null) {
-                // SortedSet, customized so that MASTER MastershipEvent appear
+                // SortedSet, customized so that MASTER MastershipData appear
                 // earlier during iteration.
-                candidates = new TreeSet<>(new MastershipEvent.MasterFirstComparator());
+                candidates = new TreeSet<>(new MastershipData.MasterFirstComparator());
                 current.mastership.put(master.getDpid(), candidates);
             }
 
@@ -379,15 +379,15 @@
          * Removes a mastership change event.
          * <p>
          * Note: Only Dpid and OnosInstanceId will be used to identify the
-         * {@link MastershipEvent} to remove.
+         * {@link MastershipData} to remove.
          *
-         * @param master {@link MastershipEvent} to remove. (Role is ignored)
+         * @param master {@link MastershipData} to remove. (Role is ignored)
          * @return Builder
          */
-        public Builder removeSwitchMastershipEvent(MastershipEvent master) {
+        public Builder removeSwitchMastershipData(MastershipData master) {
             checkNotNull(master);
 
-            SortedSet<MastershipEvent> candidates
+            SortedSet<MastershipData> candidates
                 = current.mastership.get(master.getDpid());
             if (candidates == null) {
                 // nothing to do
@@ -429,7 +429,7 @@
 
         // shallow copy Set in Map
         this.mastership = new HashMap<>(builder.current.mastership.size());
-        for (Entry<Dpid, SortedSet<MastershipEvent>> e
+        for (Entry<Dpid, SortedSet<MastershipData>> e
                     : builder.current.mastership.entrySet()) {
             this.mastership.put(e.getKey(), new TreeSet<>(e.getValue()));
         }
@@ -475,7 +475,7 @@
 
         // shallow copy Set in Map
         this.mastership = new HashMap<>(original.mastership.size());
-        for (Entry<Dpid, SortedSet<MastershipEvent>> e
+        for (Entry<Dpid, SortedSet<MastershipData>> e
                         : original.mastership.entrySet()) {
             this.mastership.put(e.getKey(), new TreeSet<>(e.getValue()));
         }
@@ -672,11 +672,11 @@
      */
     @Override
     public OnosInstanceId getSwitchMaster(Dpid dpid) {
-        final SortedSet<MastershipEvent> candidates = mastership.get(dpid);
+        final SortedSet<MastershipData> candidates = mastership.get(dpid);
         if (candidates == null) {
             return null;
         }
-        for (MastershipEvent candidate : candidates) {
+        for (MastershipData candidate : candidates) {
             if (candidate.getRole() == Role.MASTER) {
                 return candidate.getOnosInstanceId();
             }
diff --git a/src/main/java/net/onrc/onos/core/topology/MastershipEvent.java b/src/main/java/net/onrc/onos/core/topology/MastershipData.java
similarity index 74%
rename from src/main/java/net/onrc/onos/core/topology/MastershipEvent.java
rename to src/main/java/net/onrc/onos/core/topology/MastershipData.java
index d816376..9942f05 100644
--- a/src/main/java/net/onrc/onos/core/topology/MastershipEvent.java
+++ b/src/main/java/net/onrc/onos/core/topology/MastershipData.java
@@ -9,21 +9,17 @@
 import java.util.Objects;
 
 import net.floodlightcontroller.core.IFloodlightProviderService.Role;
-import net.onrc.onos.core.topology.web.serializers.MastershipEventSerializer;
+import net.onrc.onos.core.topology.web.serializers.MastershipDataSerializer;
 import net.onrc.onos.core.util.Dpid;
 import net.onrc.onos.core.util.OnosInstanceId;
 
 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.
+ * Self-contained Switch Mastership object.
  */
-@JsonSerialize(using = MastershipEventSerializer.class)
-public class MastershipEvent extends TopologyElement<MastershipEvent> {
+@JsonSerialize(using = MastershipDataSerializer.class)
+public class MastershipData extends TopologyElement<MastershipData> {
     private final Dpid dpid;
     private final OnosInstanceId onosInstanceId;
     private final Role role;
@@ -32,7 +28,7 @@
      * Default constructor for Serializer to use.
      */
     @Deprecated
-    protected MastershipEvent() {
+    protected MastershipData() {
         dpid = null;
         onosInstanceId = null;
         role = Role.SLAVE;              // Default role is SLAVE
@@ -46,7 +42,7 @@
      * @param onosInstanceId the ONOS Instance ID
      * @param role the ONOS instance role for the switch
      */
-    public MastershipEvent(Dpid dpid, OnosInstanceId onosInstanceId,
+    public MastershipData(Dpid dpid, OnosInstanceId onosInstanceId,
                            Role role) {
         this.dpid = checkNotNull(dpid);
         this.onosInstanceId = checkNotNull(onosInstanceId);
@@ -56,11 +52,11 @@
     /**
      * Copy constructor.
      * <p>
-     * Creates an unfrozen copy of the given Switch MastershipEvent object.
+     * Creates an unfrozen copy of the given Switch MastershipData object.
      *
      * @param original the object to make copy of
      */
-    public MastershipEvent(MastershipEvent original) {
+    public MastershipData(MastershipData original) {
         super(original);
         this.dpid = original.dpid;
         this.onosInstanceId = original.onosInstanceId;
@@ -113,8 +109,8 @@
     }
 
     /**
-     * Compares two MastershipEvent objects.
-     * MastershipEvent objects are equal if they have same DPID and same
+     * Compares two MastershipData objects.
+     * MastershipData objects are equal if they have same DPID and same
      * ONOS Instance ID.
      *
      * @param o another object to compare to this
@@ -135,24 +131,24 @@
             return false;
         }
 
-        MastershipEvent other = (MastershipEvent) o;
+        MastershipData other = (MastershipData) o;
         return Objects.equals(dpid, other.dpid) &&
             Objects.equals(onosInstanceId, other.onosInstanceId);
     }
 
     /**
-     * Comparator to bring {@link MastershipEvent} with MASTER role up front.
+     * Comparator to bring {@link MastershipData} with MASTER role up front.
      * <p>
-     * Note: expected to be used against Collection of MastershipEvents
+     * Note: expected to be used against Collection of MastershipData
      * about same Dpid.
      */
     public static final class MasterFirstComparator
-                implements Comparator<MastershipEvent>, Serializable {
+                implements Comparator<MastershipData>, Serializable {
         @Override
-        public int compare(MastershipEvent o1, MastershipEvent o2) {
-            // MastershipEvent for same ONOS Instance
+        public int compare(MastershipData o1, MastershipData o2) {
+            // MastershipData for same ONOS Instance
             //  => treat as equal regardless of Role
-            // Note: MastershipEvent#equals() does not use Role
+            // Note: MastershipData#equals() does not use Role
             if (o1.equals(o2)) {
                 return 0;
             }
@@ -173,7 +169,7 @@
 
     @Override
     public String toString() {
-        return "[MastershipEvent " + getDpid() + "@" + getOnosInstanceId() +
+        return "[MastershipData " + getDpid() + "@" + getOnosInstanceId() +
             "->" + getRole() + "]";
     }
 }
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 2c805e8..2df7114 100644
--- a/src/main/java/net/onrc/onos/core/topology/TopologyEvent.java
+++ b/src/main/java/net/onrc/onos/core/topology/TopologyEvent.java
@@ -59,13 +59,13 @@
     /**
      * Constructor for given Switch Mastership event.
      *
-     * @param mastershipEvent the Switch Mastership event to use.
+     * @param mastershipData the Switch Mastership event to use.
      * @param onosInstanceId the ONOS Instance ID that originates the event.
      */
-    TopologyEvent(MastershipEvent mastershipEvent,
+    TopologyEvent(MastershipData mastershipData,
                   OnosInstanceId onosInstanceId) {
         this.eventType = Type.MASTERSHIP;
-        this.event = checkNotNull(mastershipEvent);
+        this.event = checkNotNull(mastershipData);
         this.onosInstanceId = checkNotNull(onosInstanceId);
     }
 
@@ -131,12 +131,12 @@
      *
      * @return the Mastership event.
      */
-    public MastershipEvent getMastershipEvent() {
+    public MastershipData getMastershipData() {
         if (eventType != Type.MASTERSHIP) {
             return null;
         }
-        MastershipEvent mastershipEvent = (MastershipEvent) event;
-        return mastershipEvent;
+        MastershipData mastershipData = (MastershipData) event;
+        return mastershipData;
     }
 
     /**
diff --git a/src/main/java/net/onrc/onos/core/topology/TopologyEventPreprocessor.java b/src/main/java/net/onrc/onos/core/topology/TopologyEventPreprocessor.java
index a843fb5..ebdde8f 100644
--- a/src/main/java/net/onrc/onos/core/topology/TopologyEventPreprocessor.java
+++ b/src/main/java/net/onrc/onos/core/topology/TopologyEventPreprocessor.java
@@ -215,18 +215,18 @@
      * @return a list of postponed events if the processed event is a
      * Mastership Event for a new Master, otherwise an empty list.
      */
-    private List<EventEntry<TopologyEvent>> processMastershipEvent(
+    private List<EventEntry<TopologyEvent>> processMastershipData(
                         OnosInstanceLastAddEvents instance,
                         EventEntry<TopologyEvent> event) {
         TopologyEvent topologyEvent = event.eventData();
-        MastershipEvent mastershipEvent = topologyEvent.getMastershipEvent();
+        MastershipData mastershipData = topologyEvent.getMastershipData();
 
-        if (mastershipEvent == null) {
+        if (mastershipData == null) {
             return Collections.emptyList();  // Not a Mastership Event
         }
 
         OnosInstanceId onosInstanceId = topologyEvent.getOnosInstanceId();
-        Dpid dpid = mastershipEvent.getDpid();
+        Dpid dpid = mastershipData.getDpid();
         boolean newMaster = false;
 
         //
@@ -239,7 +239,7 @@
         //    the current MASTER.
         //
         if ((event.eventType() == EventEntry.Type.ENTRY_ADD) &&
-            (mastershipEvent.getRole() == Role.MASTER)) {
+            (mastershipData.getRole() == Role.MASTER)) {
 
             //
             // Accept if explicitly configured, otherwise check
@@ -313,7 +313,7 @@
                 instanceState.put(onosInstanceId, instance);
             }
 
-            postponedEvents = processMastershipEvent(instance, event);
+            postponedEvents = processMastershipData(instance, event);
 
             //
             // Process the event and eventually store it in the
@@ -339,7 +339,7 @@
      * <p/>
      * The result events can be applied to the Topology in the following
      * order: REMOVE events followed by ADD events. The ADD events are in the
-     * natural order to build a Topology: MastershipEvent, SwitchData,
+     * natural order to build a Topology: MastershipData, SwitchData,
      * PortData, LinkData, HostData. The REMOVE events are in the reverse
      * order.
      *
@@ -349,9 +349,9 @@
     private List<EventEntry<TopologyEvent>> reorderEventsForTopology(
                 List<EventEntry<TopologyEvent>> events) {
         // Local state for computing the final set of events
-        Map<ByteBuffer, EventEntry<TopologyEvent>> addedMastershipEvents =
+        Map<ByteBuffer, EventEntry<TopologyEvent>> addedMastershipDataEntries =
             new HashMap<>();
-        Map<ByteBuffer, EventEntry<TopologyEvent>> removedMastershipEvents =
+        Map<ByteBuffer, EventEntry<TopologyEvent>> removedMastershipDataEntries =
             new HashMap<>();
         Map<ByteBuffer, EventEntry<TopologyEvent>> addedSwitchDataEntries =
             new HashMap<>();
@@ -381,8 +381,8 @@
             TopologyEvent topologyEvent = event.eventData();
 
             // Get the event itself
-            MastershipEvent mastershipEvent =
-                topologyEvent.getMastershipEvent();
+            MastershipData mastershipData =
+                topologyEvent.getMastershipData();
             SwitchData switchData = topologyEvent.getSwitchData();
             PortData portData = topologyEvent.getPortData();
             LinkData linkData = topologyEvent.getLinkData();
@@ -393,10 +393,10 @@
             //
             switch (event.eventType()) {
             case ENTRY_ADD:
-                if (mastershipEvent != null) {
-                    ByteBuffer id = mastershipEvent.getIDasByteBuffer();
-                    addedMastershipEvents.put(id, event);
-                    removedMastershipEvents.remove(id);
+                if (mastershipData != null) {
+                    ByteBuffer id = mastershipData.getIDasByteBuffer();
+                    addedMastershipDataEntries.put(id, event);
+                    removedMastershipDataEntries.remove(id);
                 }
                 if (switchData != null) {
                     ByteBuffer id = switchData.getIDasByteBuffer();
@@ -420,10 +420,10 @@
                 }
                 break;
             case ENTRY_REMOVE:
-                if (mastershipEvent != null) {
-                    ByteBuffer id = mastershipEvent.getIDasByteBuffer();
-                    addedMastershipEvents.remove(id);
-                    removedMastershipEvents.put(id, event);
+                if (mastershipData != null) {
+                    ByteBuffer id = mastershipData.getIDasByteBuffer();
+                    addedMastershipDataEntries.remove(id);
+                    removedMastershipDataEntries.put(id, event);
                 }
                 if (switchData != null) {
                     ByteBuffer id = switchData.getIDasByteBuffer();
@@ -463,9 +463,9 @@
         result.addAll(removedLinkDataEntries.values());
         result.addAll(removedPortDataEntries.values());
         result.addAll(removedSwitchDataEntries.values());
-        result.addAll(removedMastershipEvents.values());
+        result.addAll(removedMastershipDataEntries.values());
         //
-        result.addAll(addedMastershipEvents.values());
+        result.addAll(addedMastershipDataEntries.values());
         result.addAll(addedSwitchDataEntries.values());
         result.addAll(addedPortDataEntries.values());
         result.addAll(addedLinkDataEntries.values());
diff --git a/src/main/java/net/onrc/onos/core/topology/TopologyEvents.java b/src/main/java/net/onrc/onos/core/topology/TopologyEvents.java
index 9bb9184..bd346e6 100644
--- a/src/main/java/net/onrc/onos/core/topology/TopologyEvents.java
+++ b/src/main/java/net/onrc/onos/core/topology/TopologyEvents.java
@@ -17,10 +17,10 @@
  * <p/>
  * (b) The processing order of the "removed" events should be:
  * removedHostDataEntries, removedLinkDataEntries, removedPortDataEntries,
- * removedSwitchDataEntries, removedMastershipEvents
+ * removedSwitchDataEntries, removedMastershipDataEntries
  * <p/>
  * (c) The processing order of the "added" events should be:
- * addedMastershipEvents, addedSwitchDataEntries, addedPortDataEntries,
+ * addedMastershipDataEntries, addedSwitchDataEntries, addedPortDataEntries,
  * addedLinkDataEntries, addedHostDataEntries
  * <p/>
  * The above ordering guarantees that removing a port for example
@@ -32,8 +32,8 @@
  */
 @JsonSerialize(using = TopologyEventsSerializer.class)
 public final class TopologyEvents {
-    private final ImmutableList<MastershipEvent> addedMastershipEvents;
-    private final ImmutableList<MastershipEvent> removedMastershipEvents;
+    private final ImmutableList<MastershipData> addedMastershipDataEntries;
+    private final ImmutableList<MastershipData> removedMastershipDataEntries;
     private final ImmutableList<SwitchData> addedSwitchDataEntries;
     private final ImmutableList<SwitchData> removedSwitchDataEntries;
     private final ImmutableList<PortData> addedPortDataEntries;
@@ -46,25 +46,21 @@
     /**
      * Constructor for added and removed events.
      *
-     * @param addedMastershipEvents the collection of added Mastership Events.
-     * @param removedMastershipEvents the collection of removed Mastership
-     *        Events.
-     * @param addedSwitchDataEntries the collection of added Switch Data
-     * Entries.
-     * @param removedSwitchDataEntries the collection of removed Switch Data
-     * Entries.
-     * @param addedPortDataEntries the collection of added Port Data Entries.
-     * @param removedPortDataEntries the collection of removed Port Data
-     * Entries.
-     * @param addedLinkDataEntries the collection of added Link Data Entries.
-     * @param removedLinkDataEntries the collection of removed Link Data
-     * Entries.
-     * @param addedHostDataEntries the collection of added Host Data Entries.
-     * @param removedHostDataEntries the collection of removed Host Data
-     * Entries.
+     * @param addedMastershipDataEntries the collection of added Mastership
+     * Events
+     * @param removedMastershipDataEntries the collection of removed Mastership
+     * Events
+     * @param addedSwitchDataEntries the collection of added Switch Events
+     * @param removedSwitchDataEntries the collection of removed Switch Events
+     * @param addedPortDataEntries the collection of added Port Events
+     * @param removedPortDataEntries the collection of removed Port Events
+     * @param addedLinkDataEntries the collection of added Link Events
+     * @param removedLinkDataEntries the collection of removed Link Events
+     * @param addedHostDataEntries the collection of added Host Events
+     * @param removedHostDataEntries the collection of removed Host Events
      */
-    public TopologyEvents(Collection<MastershipEvent> addedMastershipEvents,
-                          Collection<MastershipEvent> removedMastershipEvents,
+    public TopologyEvents(Collection<MastershipData> addedMastershipDataEntries,
+                          Collection<MastershipData> removedMastershipDataEntries,
                           Collection<SwitchData> addedSwitchDataEntries,
                           Collection<SwitchData> removedSwitchDataEntries,
                           Collection<PortData> addedPortDataEntries,
@@ -73,10 +69,10 @@
                           Collection<LinkData> removedLinkDataEntries,
                           Collection<HostData> addedHostDataEntries,
                           Collection<HostData> removedHostDataEntries) {
-        this.addedMastershipEvents = ImmutableList.<MastershipEvent>copyOf(
-                        checkNotNull(addedMastershipEvents));
-        this.removedMastershipEvents = ImmutableList.<MastershipEvent>copyOf(
-                        checkNotNull(removedMastershipEvents));
+        this.addedMastershipDataEntries = ImmutableList.<MastershipData>copyOf(
+                        checkNotNull(addedMastershipDataEntries));
+        this.removedMastershipDataEntries = ImmutableList.<MastershipData>copyOf(
+                        checkNotNull(removedMastershipDataEntries));
         this.addedSwitchDataEntries = ImmutableList.<SwitchData>copyOf(
                         checkNotNull(addedSwitchDataEntries));
         this.removedSwitchDataEntries = ImmutableList.<SwitchData>copyOf(
@@ -98,19 +94,20 @@
     /**
      * Constructor for added events only.
      *
-     * @param addedMastershipEvents the collection of added Mastership Events.
-     * @param addedSwitchDataEntries the collection of added Switch Events.
-     * @param addedPortDataEntries the collection of added Port Events.
-     * @param addedLinkDataEntries the collection of added Link Events.
-     * @param addedHostDataEntries the collection of added Host Events.
+     * @param addedMastershipDataEntries the collection of added Mastership
+     * Events
+     * @param addedSwitchDataEntries the collection of added Switch Events
+     * @param addedPortDataEntries the collection of added Port Events
+     * @param addedLinkDataEntries the collection of added Link Events
+     * @param addedHostDataEntries the collection of added Host Events
      */
-    public TopologyEvents(Collection<MastershipEvent> addedMastershipEvents,
+    public TopologyEvents(Collection<MastershipData> addedMastershipDataEntries,
                           Collection<SwitchData> addedSwitchDataEntries,
                           Collection<PortData> addedPortDataEntries,
                           Collection<LinkData> addedLinkDataEntries,
                           Collection<HostData> addedHostDataEntries) {
-        this.addedMastershipEvents = ImmutableList.<MastershipEvent>copyOf(
-                        checkNotNull(addedMastershipEvents));
+        this.addedMastershipDataEntries = ImmutableList.<MastershipData>copyOf(
+                        checkNotNull(addedMastershipDataEntries));
         this.addedSwitchDataEntries = ImmutableList.<SwitchData>copyOf(
                         checkNotNull(addedSwitchDataEntries));
         this.addedPortDataEntries = ImmutableList.<PortData>copyOf(
@@ -121,7 +118,7 @@
                         checkNotNull(addedHostDataEntries));
 
         // Assign empty lists to the removed events
-        this.removedMastershipEvents = ImmutableList.<MastershipEvent>of();
+        this.removedMastershipDataEntries = ImmutableList.<MastershipData>of();
         this.removedSwitchDataEntries = ImmutableList.<SwitchData>of();
         this.removedPortDataEntries = ImmutableList.<PortData>of();
         this.removedLinkDataEntries = ImmutableList.<LinkData>of();
@@ -133,8 +130,8 @@
      *
      * @return the immutable collection of added Mastership Events.
      */
-    public Collection<MastershipEvent> getAddedMastershipEvents() {
-        return addedMastershipEvents;
+    public Collection<MastershipData> getAddedMastershipDataEntries() {
+        return addedMastershipDataEntries;
     }
 
     /**
@@ -142,8 +139,8 @@
      *
      * @return the immutable collection of removed Mastership Events.
      */
-    public Collection<MastershipEvent> getRemovedMastershipEvents() {
-        return removedMastershipEvents;
+    public Collection<MastershipData> getRemovedMastershipDataEntries() {
+        return removedMastershipDataEntries;
     }
 
     /**
diff --git a/src/main/java/net/onrc/onos/core/topology/TopologyImpl.java b/src/main/java/net/onrc/onos/core/topology/TopologyImpl.java
index c27a247..2ceb2d9 100644
--- a/src/main/java/net/onrc/onos/core/topology/TopologyImpl.java
+++ b/src/main/java/net/onrc/onos/core/topology/TopologyImpl.java
@@ -49,7 +49,7 @@
 
     // Mastership info
     // Dpid -> [ (InstanceID, Role) ]
-    private final Map<Dpid, SortedSet<MastershipEvent>> mastership;
+    private final Map<Dpid, SortedSet<MastershipData>> mastership;
 
     // DPID -> Switch
     private final ConcurrentMap<Dpid, SwitchData> switches;
@@ -93,7 +93,7 @@
         try {
             // shallow copy Set in Map
             this.mastership = new HashMap<>(original.mastership.size());
-            for (Entry<Dpid, SortedSet<MastershipEvent>> e
+            for (Entry<Dpid, SortedSet<MastershipData>> e
                         : original.mastership.entrySet()) {
                 this.mastership.put(e.getKey(), new TreeSet<>(e.getValue()));
             }
@@ -514,11 +514,11 @@
 
     @Override
     public OnosInstanceId getSwitchMaster(Dpid dpid) {
-        final SortedSet<MastershipEvent> candidates = mastership.get(dpid);
+        final SortedSet<MastershipData> candidates = mastership.get(dpid);
         if (candidates == null) {
             return null;
         }
-        for (MastershipEvent candidate : candidates) {
+        for (MastershipData candidate : candidates) {
             if (candidate.getRole() == Role.MASTER) {
                 return candidate.getOnosInstanceId();
             }
@@ -718,18 +718,18 @@
     /**
      * Puts a mastership change event.
      *
-     * @param master MastershipEvent
+     * @param master MastershipData
      */
     @GuardedBy("writeLock")
-    protected void putSwitchMastershipEvent(MastershipEvent master) {
+    protected void putSwitchMastershipData(MastershipData master) {
         checkNotNull(master);
 
-        SortedSet<MastershipEvent> candidates
+        SortedSet<MastershipData> candidates
             = mastership.get(master.getDpid());
         if (candidates == null) {
-            // SortedSet, customized so that MASTER MastershipEvent appear
+            // SortedSet, customized so that MASTER MastershipData appear
             // earlier during iteration.
-            candidates = new TreeSet<>(new MastershipEvent.MasterFirstComparator());
+            candidates = new TreeSet<>(new MastershipData.MasterFirstComparator());
         }
 
         // always replace
@@ -741,15 +741,15 @@
      * Removes a mastership change event.
      * <p>
      * Note: Only Dpid and OnosInstanceId will be used to identify the
-     * {@link MastershipEvent} to remove.
+     * {@link MastershipData} to remove.
      *
-     * @param master {@link MastershipEvent} to remove. (Role is ignored)
+     * @param master {@link MastershipData} to remove. (Role is ignored)
      */
     @GuardedBy("writeLock")
-    protected void removeSwitchMastershipEvent(MastershipEvent master) {
+    protected void removeSwitchMastershipData(MastershipData master) {
         checkNotNull(master);
 
-        SortedSet<MastershipEvent> candidates
+        SortedSet<MastershipData> candidates
             = mastership.get(master.getDpid());
         if (candidates == null) {
             // nothing to do
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 47cdcff..9092e98 100644
--- a/src/main/java/net/onrc/onos/core/topology/TopologyManager.java
+++ b/src/main/java/net/onrc/onos/core/topology/TopologyManager.java
@@ -97,7 +97,7 @@
     // Local state for keeping the last ADD Mastership Event entries.
     // TODO: In the future, we might have to keep this state somewhere else.
     //
-    private Map<ByteBuffer, MastershipEvent> lastAddMastershipEvents =
+    private Map<ByteBuffer, MastershipData> lastAddMastershipDataEntries =
         new HashMap<>();
 
     //
@@ -106,9 +106,9 @@
     //  - Queue of events, which will be dispatched to local listeners
     //    on next notification.
 
-    private List<MastershipEvent> apiAddedMastershipEvents =
+    private List<MastershipData> apiAddedMastershipDataEntries =
         new LinkedList<>();
-    private List<MastershipEvent> apiRemovedMastershipEvents =
+    private List<MastershipData> apiRemovedMastershipDataEntries =
         new LinkedList<>();
     private List<SwitchData> apiAddedSwitchDataEntries = new LinkedList<>();
     private List<SwitchData> apiRemovedSwitchDataEntries = new LinkedList<>();
@@ -233,8 +233,8 @@
                     TopologyEvent topologyEvent = event.eventData();
 
                     // Get the event itself
-                    MastershipEvent mastershipEvent =
-                        topologyEvent.getMastershipEvent();
+                    MastershipData mastershipData =
+                        topologyEvent.getMastershipData();
                     SwitchData switchData = topologyEvent.getSwitchData();
                     PortData portData = topologyEvent.getPortData();
                     LinkData linkData = topologyEvent.getLinkData();
@@ -246,8 +246,8 @@
                     //
                     switch (event.eventType()) {
                     case ENTRY_ADD:
-                        if (mastershipEvent != null) {
-                            wasAdded = addMastershipEvent(mastershipEvent);
+                        if (mastershipData != null) {
+                            wasAdded = addMastershipData(mastershipData);
                         }
                         if (switchData != null) {
                             wasAdded = addSwitch(switchData);
@@ -268,8 +268,8 @@
                         }
                         break;
                     case ENTRY_REMOVE:
-                        if (mastershipEvent != null) {
-                            removeMastershipEvent(mastershipEvent);
+                        if (mastershipData != null) {
+                            removeMastershipData(mastershipData);
                         }
                         if (switchData != null) {
                             removeSwitch(switchData);
@@ -411,18 +411,18 @@
         // Create the Topology Snapshot Event
         //
         TopologyEvents events = null;
-        Collection<MastershipEvent> mastershipEvents =
-            lastAddMastershipEvents.values();
+        Collection<MastershipData> mastershipDataEntries =
+            lastAddMastershipDataEntries.values();
         Collection<SwitchData> switchDataEntries = topology.getAllSwitchDataEntries();
         Collection<PortData> portDataEntries = topology.getAllPortDataEntries();
         Collection<LinkData> linkDataEntries = topology.getAllLinkDataEntries();
         Collection<HostData> hostDataEntries = topology.getAllHostDataEntries();
-        if (!(mastershipEvents.isEmpty() &&
+        if (!(mastershipDataEntries.isEmpty() &&
               switchDataEntries.isEmpty() &&
               portDataEntries.isEmpty() &&
               linkDataEntries.isEmpty() &&
               hostDataEntries.isEmpty())) {
-            events = new TopologyEvents(mastershipEvents,
+            events = new TopologyEvents(mastershipDataEntries,
                                         switchDataEntries,
                                         portDataEntries,
                                         linkDataEntries,
@@ -455,8 +455,8 @@
      * Dispatch Topology Events to the listeners.
      */
     private void dispatchTopologyEvents() {
-        if (apiAddedMastershipEvents.isEmpty() &&
-                apiRemovedMastershipEvents.isEmpty() &&
+        if (apiAddedMastershipDataEntries.isEmpty() &&
+                apiRemovedMastershipDataEntries.isEmpty() &&
                 apiAddedSwitchDataEntries.isEmpty() &&
                 apiRemovedSwitchDataEntries.isEmpty() &&
                 apiAddedPortDataEntries.isEmpty() &&
@@ -473,13 +473,13 @@
             // Debug statements
             // TODO: Those statements should be removed in the future
             //
-            for (MastershipEvent mastershipEvent : apiAddedMastershipEvents) {
+            for (MastershipData mastershipData : apiAddedMastershipDataEntries) {
                 log.debug("Dispatch Topology Event: ADDED {}",
-                          mastershipEvent);
+                          mastershipData);
             }
-            for (MastershipEvent mastershipEvent : apiRemovedMastershipEvents) {
+            for (MastershipData mastershipData : apiRemovedMastershipDataEntries) {
                 log.debug("Dispatch Topology Event: REMOVED {}",
-                          mastershipEvent);
+                          mastershipData);
             }
             for (SwitchData switchData : apiAddedSwitchDataEntries) {
                 log.debug("Dispatch Topology Event: ADDED {}", switchData);
@@ -511,7 +511,7 @@
         // Update the metrics
         //
         long totalEvents =
-            apiAddedMastershipEvents.size() + apiRemovedMastershipEvents.size() +
+            apiAddedMastershipDataEntries.size() + apiRemovedMastershipDataEntries.size() +
             apiAddedSwitchDataEntries.size() + apiRemovedSwitchDataEntries.size() +
             apiAddedPortDataEntries.size() + apiRemovedPortDataEntries.size() +
             apiAddedLinkDataEntries.size() + apiRemovedLinkDataEntries.size() +
@@ -523,8 +523,8 @@
         // Allocate the events to deliver.
         //
         TopologyEvents events = new TopologyEvents(
-                apiAddedMastershipEvents,
-                apiRemovedMastershipEvents,
+                apiAddedMastershipDataEntries,
+                apiRemovedMastershipDataEntries,
                 apiAddedSwitchDataEntries,
                 apiRemovedSwitchDataEntries,
                 apiAddedPortDataEntries,
@@ -544,8 +544,8 @@
         //
         // Cleanup
         //
-        apiAddedMastershipEvents.clear();
-        apiRemovedMastershipEvents.clear();
+        apiAddedMastershipDataEntries.clear();
+        apiRemovedMastershipDataEntries.clear();
         apiAddedSwitchDataEntries.clear();
         apiRemovedSwitchDataEntries.clear();
         apiAddedPortDataEntries.clear();
@@ -563,28 +563,28 @@
     /**
      * Adds Switch Mastership event.
      *
-     * @param mastershipEvent the MastershipEvent to process.
+     * @param mastershipData the MastershipData to process.
      * @return true if the item was successfully added, otherwise false.
      */
     @GuardedBy("topology.writeLock")
-    private boolean addMastershipEvent(MastershipEvent mastershipEvent) {
-        log.debug("Added Mastership event {}", mastershipEvent);
-        lastAddMastershipEvents.put(mastershipEvent.getIDasByteBuffer(),
-                                    mastershipEvent);
-        apiAddedMastershipEvents.add(mastershipEvent);
+    private boolean addMastershipData(MastershipData mastershipData) {
+        log.debug("Added Mastership event {}", mastershipData);
+        lastAddMastershipDataEntries.put(mastershipData.getIDasByteBuffer(),
+                                         mastershipData);
+        apiAddedMastershipDataEntries.add(mastershipData);
         return true;
     }
 
     /**
      * Removes Switch Mastership event.
      *
-     * @param mastershipEvent the MastershipEvent to process.
+     * @param mastershipData the MastershipData to process.
      */
     @GuardedBy("topology.writeLock")
-    private void removeMastershipEvent(MastershipEvent mastershipEvent) {
-        log.debug("Removed Mastership event {}", mastershipEvent);
-        lastAddMastershipEvents.remove(mastershipEvent.getIDasByteBuffer());
-        apiRemovedMastershipEvents.add(mastershipEvent);
+    private void removeMastershipData(MastershipData mastershipData) {
+        log.debug("Removed Mastership event {}", mastershipData);
+        lastAddMastershipDataEntries.remove(mastershipData.getIDasByteBuffer());
+        apiRemovedMastershipDataEntries.add(mastershipData);
     }
 
     /**
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 e2bdb77..be47051 100644
--- a/src/main/java/net/onrc/onos/core/topology/TopologyPublisher.java
+++ b/src/main/java/net/onrc/onos/core/topology/TopologyPublisher.java
@@ -99,7 +99,7 @@
     // TODO: What to do if the Mastership changes?
     //  - Cleanup state from publishedFoo maps, but do not send REMOVE events?
     //
-    private ConcurrentMap<Dpid, MastershipEvent> publishedMastershipEvents =
+    private ConcurrentMap<Dpid, MastershipData> publishedMastershipDataEntries =
         new ConcurrentHashMap<>();
     private ConcurrentMap<Dpid, SwitchData> publishedSwitchDataEntries =
         new ConcurrentHashMap<>();
@@ -398,15 +398,15 @@
 
         Role role = Role.SLAVE; // TODO: Should be Role.UNKNOWN
 
-        MastershipEvent mastershipEvent =
-                new MastershipEvent(dpid, getOnosInstanceId(), role);
+        MastershipData mastershipData =
+                new MastershipData(dpid, getOnosInstanceId(), role);
         // FIXME should be merging, with existing attrs, etc..
         // TODO define attr name as constant somewhere.
         // TODO populate appropriate attributes.
-        mastershipEvent.createStringAttribute(TopologyElement.TYPE,
+        mastershipData.createStringAttribute(TopologyElement.TYPE,
                 TopologyElement.TYPE_ALL_LAYERS);
-        mastershipEvent.freeze();
-        publishRemoveSwitchMastershipEvent(mastershipEvent);
+        mastershipData.freeze();
+        publishRemoveSwitchMastershipEvent(mastershipData);
     }
 
     @Override
@@ -625,52 +625,52 @@
     private void controllerRoleChanged(Dpid dpid, Role role) {
         log.debug("Local switch controller mastership role changed: dpid = {} role = {}",
                 dpid, role);
-        MastershipEvent mastershipEvent =
-                new MastershipEvent(dpid, getOnosInstanceId(), role);
+        MastershipData mastershipData =
+                new MastershipData(dpid, getOnosInstanceId(), role);
         // FIXME should be merging, with existing attrs, etc..
         // TODO define attr name as constant somewhere.
         // TODO populate appropriate attributes.
-        mastershipEvent.createStringAttribute(TopologyElement.TYPE,
+        mastershipData.createStringAttribute(TopologyElement.TYPE,
                 TopologyElement.TYPE_ALL_LAYERS);
-        mastershipEvent.freeze();
-        publishAddSwitchMastershipEvent(mastershipEvent);
+        mastershipData.freeze();
+        publishAddSwitchMastershipEvent(mastershipData);
     }
 
     /**
      * Publishes ADD Mastership Event.
      *
-     * @param mastershipEvent the mastership event to publish
+     * @param mastershipData the mastership event to publish
      */
     private void publishAddSwitchMastershipEvent(
-                        MastershipEvent mastershipEvent) {
+                        MastershipData mastershipData) {
         // Publish the information
         TopologyBatchOperation tbo = new TopologyBatchOperation();
         TopologyEvent topologyEvent =
-            new TopologyEvent(mastershipEvent, getOnosInstanceId());
+            new TopologyEvent(mastershipData, getOnosInstanceId());
         tbo.appendAddOperation(topologyEvent);
         publishTopologyOperations(tbo);
-        publishedMastershipEvents.put(mastershipEvent.getDpid(),
-                                      mastershipEvent);
+        publishedMastershipDataEntries.put(mastershipData.getDpid(),
+                                           mastershipData);
     }
 
     /**
      * Publishes REMOVE Mastership Event.
      *
-     * @param mastershipEvent the mastership event to publish
+     * @param mastershipData the mastership event to publish
      */
     private void publishRemoveSwitchMastershipEvent(
-                        MastershipEvent mastershipEvent) {
-        if (publishedMastershipEvents.get(mastershipEvent.getDpid()) == null) {
+                        MastershipData mastershipData) {
+        if (publishedMastershipDataEntries.get(mastershipData.getDpid()) == null) {
             return;     // Nothing to do
         }
 
         // Publish the information
         TopologyBatchOperation tbo = new TopologyBatchOperation();
         TopologyEvent topologyEvent =
-            new TopologyEvent(mastershipEvent, getOnosInstanceId());
+            new TopologyEvent(mastershipData, getOnosInstanceId());
         tbo.appendRemoveOperation(topologyEvent);
         publishTopologyOperations(tbo);
-        publishedMastershipEvents.remove(mastershipEvent.getDpid());
+        publishedMastershipDataEntries.remove(mastershipData.getDpid());
     }
 
     /**
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/MastershipDataSerializer.java
similarity index 66%
rename from src/main/java/net/onrc/onos/core/topology/web/serializers/MastershipEventSerializer.java
rename to src/main/java/net/onrc/onos/core/topology/web/serializers/MastershipDataSerializer.java
index d8c8da7..f147f0c 100644
--- a/src/main/java/net/onrc/onos/core/topology/web/serializers/MastershipEventSerializer.java
+++ b/src/main/java/net/onrc/onos/core/topology/web/serializers/MastershipDataSerializer.java
@@ -3,7 +3,7 @@
 import java.io.IOException;
 import java.util.Map.Entry;
 
-import net.onrc.onos.core.topology.MastershipEvent;
+import net.onrc.onos.core.topology.MastershipData;
 import net.onrc.onos.core.topology.TopologyElement;
 
 import org.codehaus.jackson.JsonGenerator;
@@ -11,27 +11,27 @@
 import org.codehaus.jackson.map.ser.std.SerializerBase;
 
 /**
- * JSON serializer for MastershipEvent objects.
+ * JSON serializer for MastershipData objects.
  */
-public class MastershipEventSerializer extends SerializerBase<MastershipEvent> {
+public class MastershipDataSerializer extends SerializerBase<MastershipData> {
     /**
      * Default constructor.
      */
-    public MastershipEventSerializer() {
-        super(MastershipEvent.class);
+    public MastershipDataSerializer() {
+        super(MastershipData.class);
     }
 
     /**
-     * Serializes a MastershipEvent object in JSON.
+     * Serializes a MastershipData object in JSON.
      *
-     * @param mastershipEvent the MastershipEvent that is being converted to
+     * @param mastershipData the MastershipData that is being converted to
      * JSON
      * @param jsonGenerator generator to place the serialized JSON into
      * @param serializerProvider unused but required for method override
      * @throws IOException if the JSON serialization process fails
      */
     @Override
-    public void serialize(final MastershipEvent mastershipEvent,
+    public void serialize(final MastershipData mastershipData,
                           final JsonGenerator jsonGenerator,
                           final SerializerProvider serializerProvider)
         throws IOException {
@@ -44,15 +44,15 @@
         //
 
         jsonGenerator.writeStartObject();
-        jsonGenerator.writeStringField(TopologyElement.TYPE, mastershipEvent.getType());
+        jsonGenerator.writeStringField(TopologyElement.TYPE, mastershipData.getType());
         jsonGenerator.writeStringField("dpid",
-                                       mastershipEvent.getDpid().toString());
+                                       mastershipData.getDpid().toString());
         jsonGenerator.writeStringField("onosInstanceId",
-                                       mastershipEvent.getOnosInstanceId().toString());
+                                       mastershipData.getOnosInstanceId().toString());
         jsonGenerator.writeStringField("role",
-                                       mastershipEvent.getRole().name());
+                                       mastershipData.getRole().name());
         jsonGenerator.writeObjectFieldStart("stringAttributes");
-        for (Entry<String, String> entry : mastershipEvent.getAllStringAttributes().entrySet()) {
+        for (Entry<String, String> entry : mastershipData.getAllStringAttributes().entrySet()) {
             jsonGenerator.writeStringField(entry.getKey(), entry.getValue());
         }
         jsonGenerator.writeEndObject();         // stringAttributes
diff --git a/src/main/java/net/onrc/onos/core/topology/web/serializers/TopologyEventsSerializer.java b/src/main/java/net/onrc/onos/core/topology/web/serializers/TopologyEventsSerializer.java
index 2737ec7..477fc45 100644
--- a/src/main/java/net/onrc/onos/core/topology/web/serializers/TopologyEventsSerializer.java
+++ b/src/main/java/net/onrc/onos/core/topology/web/serializers/TopologyEventsSerializer.java
@@ -4,7 +4,7 @@
 
 import net.onrc.onos.core.topology.HostData;
 import net.onrc.onos.core.topology.LinkData;
-import net.onrc.onos.core.topology.MastershipEvent;
+import net.onrc.onos.core.topology.MastershipData;
 import net.onrc.onos.core.topology.PortData;
 import net.onrc.onos.core.topology.SwitchData;
 import net.onrc.onos.core.topology.TopologyEvents;
@@ -43,15 +43,15 @@
 
         // Output the added switch mastership array
         jsonGenerator.writeArrayFieldStart("addedSwitchMasterships");
-        for (final MastershipEvent mastershipEvent : topologyEvents.getAddedMastershipEvents()) {
-            jsonGenerator.writeObject(mastershipEvent);
+        for (final MastershipData mastershipData : topologyEvents.getAddedMastershipDataEntries()) {
+            jsonGenerator.writeObject(mastershipData);
         }
         jsonGenerator.writeEndArray();
 
         // Output the removed switch mastership array
         jsonGenerator.writeArrayFieldStart("removedSwitchMasterships");
-        for (final MastershipEvent mastershipEvent : topologyEvents.getRemovedMastershipEvents()) {
-            jsonGenerator.writeObject(mastershipEvent);
+        for (final MastershipData mastershipData : topologyEvents.getRemovedMastershipDataEntries()) {
+            jsonGenerator.writeObject(mastershipData);
         }
         jsonGenerator.writeEndArray();
 
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 7f67289..fbb7999 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
@@ -64,7 +64,7 @@
 import net.onrc.onos.core.topology.ConfigState;
 import net.onrc.onos.core.topology.HostData;
 import net.onrc.onos.core.topology.LinkData;
-import net.onrc.onos.core.topology.MastershipEvent;
+import net.onrc.onos.core.topology.MastershipData;
 import net.onrc.onos.core.topology.PortData;
 import net.onrc.onos.core.topology.SwitchData;
 import net.onrc.onos.core.topology.TopologyBatchOperation;
@@ -203,7 +203,7 @@
         kryo.register(HostData.class);
         kryo.register(LinkedList.class);
         kryo.register(LinkData.class);
-        kryo.register(MastershipEvent.class);
+        kryo.register(MastershipData.class);
         kryo.register(OnosInstanceId.class);
         kryo.register(PortData.class);
         kryo.register(Role.class);