diff --git a/core/api/src/main/java/org/onlab/onos/cluster/MastershipService.java b/core/api/src/main/java/org/onlab/onos/cluster/MastershipService.java
index be91609..d417516 100644
--- a/core/api/src/main/java/org/onlab/onos/cluster/MastershipService.java
+++ b/core/api/src/main/java/org/onlab/onos/cluster/MastershipService.java
@@ -56,7 +56,8 @@
     Set<DeviceId> getDevicesOf(NodeId nodeId);
 
     /**
-     * Returns the mastership term service for getting term information.
+     * Returns the mastership term service for getting read-only
+     * term information.
      *
      * @return the MastershipTermService for this mastership manager
      */
diff --git a/core/api/src/main/java/org/onlab/onos/cluster/MastershipStore.java b/core/api/src/main/java/org/onlab/onos/cluster/MastershipStore.java
index be5d873..bedc5e9 100644
--- a/core/api/src/main/java/org/onlab/onos/cluster/MastershipStore.java
+++ b/core/api/src/main/java/org/onlab/onos/cluster/MastershipStore.java
@@ -64,4 +64,14 @@
      * @return the current master's ID and the term value for device, or null
      */
     MastershipTerm getTermFor(DeviceId deviceId);
+
+    /**
+     * Revokes a controller instance's mastership over a device and hands
+     * over mastership to another controller instance.
+     *
+     * @param nodeId   the controller instance identifier
+     * @param deviceId device to revoke mastership for
+     * @return a mastership event
+     */
+    MastershipEvent unsetMaster(NodeId nodeId, DeviceId deviceId);
 }
diff --git a/core/api/src/test/java/org/onlab/onos/cluster/MastershipTermTest.java b/core/api/src/test/java/org/onlab/onos/cluster/MastershipTermTest.java
new file mode 100644
index 0000000..139c695
--- /dev/null
+++ b/core/api/src/test/java/org/onlab/onos/cluster/MastershipTermTest.java
@@ -0,0 +1,32 @@
+package org.onlab.onos.cluster;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+import com.google.common.testing.EqualsTester;
+
+public class MastershipTermTest {
+
+    private static final NodeId N1 = new NodeId("foo");
+    private static final NodeId N2 = new NodeId("bar");
+
+    private static final MastershipTerm TERM1 = MastershipTerm.of(N1, 0);
+    private static final MastershipTerm TERM2 = MastershipTerm.of(N2, 1);
+    private static final MastershipTerm TERM3 = MastershipTerm.of(N2, 1);
+    private static final MastershipTerm TERM4 = MastershipTerm.of(N1, 1);
+
+    @Test
+    public void basics() {
+        assertEquals("incorrect term number", 0, TERM1.termNumber());
+        assertEquals("incorrect master", new NodeId("foo"), TERM1.master());
+    }
+
+    @Test
+    public void testEquality() {
+        new EqualsTester().addEqualityGroup(MastershipTerm.of(N1, 0), TERM1)
+        .addEqualityGroup(TERM2, TERM3)
+        .addEqualityGroup(TERM4);
+    }
+
+}
diff --git a/core/net/src/main/java/org/onlab/onos/cluster/impl/MastershipManager.java b/core/net/src/main/java/org/onlab/onos/cluster/impl/MastershipManager.java
index 1a0c408..20ebc40 100644
--- a/core/net/src/main/java/org/onlab/onos/cluster/impl/MastershipManager.java
+++ b/core/net/src/main/java/org/onlab/onos/cluster/impl/MastershipManager.java
@@ -11,6 +11,8 @@
 import org.apache.felix.scr.annotations.Reference;
 import org.apache.felix.scr.annotations.ReferenceCardinality;
 import org.apache.felix.scr.annotations.Service;
+import org.onlab.onos.cluster.ClusterEvent;
+import org.onlab.onos.cluster.ClusterEventListener;
 import org.onlab.onos.cluster.ClusterService;
 import org.onlab.onos.cluster.MastershipAdminService;
 import org.onlab.onos.cluster.MastershipEvent;
@@ -52,9 +54,12 @@
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     protected ClusterService clusterService;
 
+    private ClusterEventListener clusterListener = new InternalClusterEventListener();
+
     @Activate
     public void activate() {
         eventDispatcher.addSink(MastershipEvent.class, listenerRegistry);
+        clusterService.addListener(clusterListener);
         store.setDelegate(delegate);
         log.info("Started");
     }
@@ -62,6 +67,7 @@
     @Deactivate
     public void deactivate() {
         eventDispatcher.removeSink(MastershipEvent.class);
+        clusterService.removeListener(clusterListener);
         store.unsetDelegate(delegate);
         log.info("Stopped");
     }
@@ -71,9 +77,20 @@
         checkNotNull(nodeId, NODE_ID_NULL);
         checkNotNull(deviceId, DEVICE_ID_NULL);
         checkNotNull(role, ROLE_NULL);
-        //TODO figure out appropriate action for non-MASTER roles, if we even set those
-        if (role.equals(MastershipRole.MASTER)) {
-            MastershipEvent event = store.setMaster(nodeId, deviceId);
+
+        MastershipRole current = store.getRole(nodeId, deviceId);
+        if (role.equals(current)) {
+            return;
+        } else {
+            MastershipEvent event = null;
+            if (role.equals(MastershipRole.MASTER)) {
+                //current was STANDBY, wanted MASTER
+                event = store.setMaster(nodeId, deviceId);
+            } else {
+                //current was MASTER, wanted STANDBY
+                event = store.unsetMaster(nodeId, deviceId);
+            }
+
             if (event != null) {
                 post(event);
             }
@@ -89,7 +106,18 @@
     @Override
     public void relinquishMastership(DeviceId deviceId) {
         checkNotNull(deviceId, DEVICE_ID_NULL);
-        // FIXME: add method to store to give up mastership and trigger new master selection process
+
+        MastershipRole role = store.getRole(
+                clusterService.getLocalNode().id(), deviceId);
+        if (!role.equals(MastershipRole.MASTER)) {
+            return;
+        }
+
+        MastershipEvent event = store.unsetMaster(
+                clusterService.getLocalNode().id(), deviceId);
+        if (event != null) {
+            post(event);
+        }
     }
 
     @Override
@@ -146,6 +174,26 @@
 
     }
 
+    //callback for reacting to cluster events
+    private class InternalClusterEventListener implements ClusterEventListener {
+
+        @Override
+        public void event(ClusterEvent event) {
+            switch (event.type()) {
+                //FIXME: worry about addition when the time comes
+                case INSTANCE_ADDED:
+                case INSTANCE_ACTIVATED:
+                     break;
+                case INSTANCE_REMOVED:
+                case INSTANCE_DEACTIVATED:
+                    break;
+                default:
+                    log.warn("unknown cluster event {}", event);
+            }
+        }
+
+    }
+
     public class InternalDelegate implements MastershipStoreDelegate {
 
         @Override
diff --git a/core/net/src/main/java/org/onlab/onos/net/device/impl/DeviceManager.java b/core/net/src/main/java/org/onlab/onos/net/device/impl/DeviceManager.java
index e7f2697..eb409a5 100644
--- a/core/net/src/main/java/org/onlab/onos/net/device/impl/DeviceManager.java
+++ b/core/net/src/main/java/org/onlab/onos/net/device/impl/DeviceManager.java
@@ -16,6 +16,7 @@
 import org.onlab.onos.cluster.MastershipEvent;
 import org.onlab.onos.cluster.MastershipListener;
 import org.onlab.onos.cluster.MastershipService;
+import org.onlab.onos.cluster.MastershipTermService;
 import org.onlab.onos.cluster.MastershipTerm;
 import org.onlab.onos.event.AbstractListenerRegistry;
 import org.onlab.onos.event.EventDeliveryService;
@@ -76,6 +77,8 @@
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     protected MastershipService mastershipService;
 
+    protected MastershipTermService termService;
+
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     protected ClockService clockService;
 
@@ -84,6 +87,7 @@
         store.setDelegate(delegate);
         eventDispatcher.addSink(DeviceEvent.class, listenerRegistry);
         mastershipService.addListener(mastershipListener);
+        termService = mastershipService.requestTermService();
         log.info("Started");
     }
 
@@ -208,8 +212,11 @@
             checkNotNull(deviceId, DEVICE_ID_NULL);
             checkValidity();
             DeviceEvent event = store.markOffline(deviceId);
+
+            //we're no longer capable of mastership.
             if (event != null) {
                 log.info("Device {} disconnected", deviceId);
+                mastershipService.relinquishMastership(deviceId);
                 post(event);
             }
         }
diff --git a/core/net/src/main/java/org/onlab/onos/net/topology/impl/DefaultTopologyProvider.java b/core/net/src/main/java/org/onlab/onos/net/topology/impl/DefaultTopologyProvider.java
index 770f368..7ee6ddd 100644
--- a/core/net/src/main/java/org/onlab/onos/net/topology/impl/DefaultTopologyProvider.java
+++ b/core/net/src/main/java/org/onlab/onos/net/topology/impl/DefaultTopologyProvider.java
@@ -65,8 +65,8 @@
     private volatile boolean isStarted = false;
 
     private TopologyProviderService providerService;
-    private DeviceListener deviceListener = new InnerDeviceListener();
-    private LinkListener linkListener = new InnerLinkListener();
+    private DeviceListener deviceListener = new InternalDeviceListener();
+    private LinkListener linkListener = new InternalLinkListener();
 
     private EventAccumulator accumulator;
     private ExecutorService executor;
@@ -132,7 +132,7 @@
     }
 
     // Callback for device events
-    private class InnerDeviceListener implements DeviceListener {
+    private class InternalDeviceListener implements DeviceListener {
         @Override
         public void event(DeviceEvent event) {
             DeviceEvent.Type type = event.type();
@@ -144,7 +144,7 @@
     }
 
     // Callback for link events
-    private class InnerLinkListener implements LinkListener {
+    private class InternalLinkListener implements LinkListener {
         @Override
         public void event(LinkEvent event) {
             accumulator.add(event);
diff --git a/core/net/src/test/java/org/onlab/onos/cluster/impl/MastershipManagerTest.java b/core/net/src/test/java/org/onlab/onos/cluster/impl/MastershipManagerTest.java
index d4a13ab..fd67681 100644
--- a/core/net/src/test/java/org/onlab/onos/cluster/impl/MastershipManagerTest.java
+++ b/core/net/src/test/java/org/onlab/onos/cluster/impl/MastershipManagerTest.java
@@ -19,6 +19,7 @@
 import org.onlab.packet.IpPrefix;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
 import static org.onlab.onos.net.MastershipRole.*;
 
 /**
@@ -65,7 +66,24 @@
 
     @Test
     public void relinquishMastership() {
-        //TODO
+        //no backups - should turn to standby and no master for device
+        mgr.setRole(NID_LOCAL, DEV_MASTER, MASTER);
+        assertEquals("wrong role:", MASTER, mgr.getLocalRole(DEV_MASTER));
+        mgr.relinquishMastership(DEV_MASTER);
+        assertNull("wrong master:", mgr.getMasterFor(DEV_OTHER));
+        assertEquals("wrong role:", STANDBY, mgr.getLocalRole(DEV_MASTER));
+
+        //not master, nothing should happen
+        mgr.setRole(NID_LOCAL, DEV_OTHER, STANDBY);
+        mgr.relinquishMastership(DEV_OTHER);
+        assertNull("wrong role:", mgr.getMasterFor(DEV_OTHER));
+
+        //provide NID_OTHER as backup and relinquish
+        mgr.setRole(NID_LOCAL, DEV_MASTER, MASTER);
+        assertEquals("wrong master:", NID_LOCAL, mgr.getMasterFor(DEV_MASTER));
+        mgr.setRole(NID_OTHER, DEV_MASTER, STANDBY);
+        mgr.relinquishMastership(DEV_MASTER);
+        assertEquals("wrong master:", NID_OTHER, mgr.getMasterFor(DEV_MASTER));
     }
 
     @Test
diff --git a/core/store/hz/cluster/src/main/java/org/onlab/onos/store/cluster/impl/DistributedMastershipStore.java b/core/store/hz/cluster/src/main/java/org/onlab/onos/store/cluster/impl/DistributedMastershipStore.java
index 4f6103c..ccb2937 100644
--- a/core/store/hz/cluster/src/main/java/org/onlab/onos/store/cluster/impl/DistributedMastershipStore.java
+++ b/core/store/hz/cluster/src/main/java/org/onlab/onos/store/cluster/impl/DistributedMastershipStore.java
@@ -123,6 +123,12 @@
         return null;
     }
 
+    @Override
+    public MastershipEvent unsetMaster(NodeId nodeId, DeviceId deviceId) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
     private class RemoteMasterShipEventHandler extends RemoteCacheEventHandler<DeviceId, NodeId> {
         public RemoteMasterShipEventHandler(LoadingCache<DeviceId, Optional<NodeId>> cache) {
             super(cache);
diff --git a/core/store/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleMastershipStore.java b/core/store/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleMastershipStore.java
index 61dbe61..6690707 100644
--- a/core/store/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleMastershipStore.java
+++ b/core/store/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleMastershipStore.java
@@ -5,10 +5,9 @@
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
-import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.atomic.AtomicInteger;
 
 import org.apache.felix.scr.annotations.Activate;
@@ -28,6 +27,8 @@
 import org.onlab.packet.IpPrefix;
 import org.slf4j.Logger;
 
+import com.google.common.collect.Lists;
+
 import static org.onlab.onos.cluster.MastershipEvent.Type.*;
 
 /**
@@ -48,8 +49,10 @@
             new DefaultControllerNode(new NodeId("local"), LOCALHOST);
 
     //devices mapped to their masters, to emulate multiple nodes
-    protected final ConcurrentMap<DeviceId, NodeId> masterMap =
-            new ConcurrentHashMap<>();
+    protected final Map<DeviceId, NodeId> masterMap = new HashMap<>();
+    //emulate backups
+    protected final Map<DeviceId, List<NodeId>> backupMap = new HashMap<>();
+    //terms
     protected final Map<DeviceId, AtomicInteger> termMap = new HashMap<>();
 
     @Activate
@@ -65,24 +68,38 @@
     @Override
     public MastershipEvent setMaster(NodeId nodeId, DeviceId deviceId) {
 
-        NodeId node = masterMap.get(deviceId);
-        if (node == null) {
-            synchronized (this) {
-                masterMap.put(deviceId, nodeId);
-                termMap.put(deviceId, new AtomicInteger());
-            }
-            return new MastershipEvent(MASTER_CHANGED, deviceId, nodeId);
-        }
+        NodeId current = masterMap.get(deviceId);
+        List<NodeId> backups = backupMap.get(deviceId);
 
-        if (node.equals(nodeId)) {
+        if (current == null) {
+            if (backups == null) {
+                //add new mapping to everything
+                synchronized (this) {
+                    masterMap.put(deviceId, nodeId);
+                    backups = Lists.newLinkedList();
+                    backupMap.put(deviceId, backups);
+                    termMap.put(deviceId, new AtomicInteger());
+                }
+            } else {
+                //set master to new node and remove from backups if there
+                synchronized (this) {
+                    masterMap.put(deviceId, nodeId);
+                    backups.remove(nodeId);
+                    termMap.get(deviceId).incrementAndGet();
+                }
+            }
+        } else if (current.equals(nodeId)) {
             return null;
         } else {
-            synchronized (this) {
-                masterMap.put(deviceId, nodeId);
-                termMap.get(deviceId).incrementAndGet();
-                return new MastershipEvent(MASTER_CHANGED, deviceId, nodeId);
-            }
+            //add current to backup, set master to new node
+            masterMap.put(deviceId, nodeId);
+            backups.add(current);
+            backups.remove(nodeId);
+            termMap.get(deviceId).incrementAndGet();
         }
+
+        updateStandby(nodeId, deviceId);
+        return new MastershipEvent(MASTER_CHANGED, deviceId, nodeId);
     }
 
     @Override
@@ -108,29 +125,97 @@
 
     @Override
     public MastershipRole getRole(NodeId nodeId, DeviceId deviceId) {
-        NodeId node = masterMap.get(deviceId);
-        MastershipRole role;
-        if (node != null) {
-            if (node.equals(nodeId)) {
-                role = MastershipRole.MASTER;
-            } else {
-                role = MastershipRole.STANDBY;
+        NodeId current = masterMap.get(deviceId);
+        List<NodeId> backups = backupMap.get(deviceId);
+
+        if (current == null) {
+            //masterMap or backup doesn't contain device. Say new node is MASTER
+            if (backups == null) {
+                synchronized (this) {
+                    masterMap.put(deviceId, nodeId);
+                    backups = Lists.newLinkedList();
+                    backupMap.put(deviceId, backups);
+                    termMap.put(deviceId, new AtomicInteger());
+                }
+                updateStandby(nodeId, deviceId);
+                return MastershipRole.MASTER;
             }
+
+            //device once existed, but got removed, and is now getting a backup.
+            if (!backups.contains(nodeId)) {
+                synchronized (this) {
+                    backups.add(nodeId);
+                    termMap.put(deviceId, new AtomicInteger());
+                }
+                updateStandby(nodeId, deviceId);
+            }
+
+        } else if (current.equals(nodeId)) {
+            return  MastershipRole.MASTER;
         } else {
-            //masterMap doesn't contain it.
-            role = MastershipRole.MASTER;
-            masterMap.put(deviceId, nodeId);
+            //once created, a device never has a null backups list.
+            if (!backups.contains(nodeId)) {
+                //we must have requested STANDBY setting
+                synchronized (this) {
+                    backups.add(nodeId);
+                    termMap.put(deviceId, new AtomicInteger());
+                }
+                updateStandby(nodeId, deviceId);
+            }
         }
-        return role;
+
+        return MastershipRole.STANDBY;
     }
 
     @Override
     public MastershipTerm getTermFor(DeviceId deviceId) {
-        if (masterMap.get(deviceId) == null) {
+        if ((masterMap.get(deviceId) == null) ||
+                (termMap.get(deviceId) == null)) {
             return null;
         }
         return MastershipTerm.of(
                 masterMap.get(deviceId), termMap.get(deviceId).get());
     }
 
+    @Override
+    public MastershipEvent unsetMaster(NodeId nodeId, DeviceId deviceId) {
+        NodeId node = masterMap.get(deviceId);
+
+        //TODO case where node is completely removed from the cluster?
+        if (node.equals(nodeId)) {
+            synchronized (this) {
+                //pick new node.
+                List<NodeId> backups = backupMap.get(deviceId);
+
+                //no backups, so device is hosed
+                if (backups.isEmpty()) {
+                    masterMap.remove(deviceId);
+                    backups.add(nodeId);
+                    return null;
+                }
+                NodeId backup = backups.remove(0);
+                masterMap.put(deviceId, backup);
+                backups.add(nodeId);
+                return new MastershipEvent(MASTER_CHANGED, deviceId, backup);
+            }
+        }
+        return null;
+    }
+
+    //add node as STANDBY to maps un-scalably.
+    private void updateStandby(NodeId nodeId, DeviceId deviceId) {
+        for (Map.Entry<DeviceId, List<NodeId>> e : backupMap.entrySet()) {
+            DeviceId dev = e.getKey();
+            if (dev.equals(deviceId)) {
+                continue;
+            }
+            synchronized (this) {
+                List<NodeId> nodes = e.getValue();
+                if (!nodes.contains(nodeId)) {
+                    nodes.add(nodeId);
+                }
+            }
+        }
+    }
+
 }