diff --git a/apps/sdnip/src/main/java/org/onlab/onos/sdnip/SdnIp.java b/apps/sdnip/src/main/java/org/onlab/onos/sdnip/SdnIp.java
index 4abefa7..c54e3f4 100644
--- a/apps/sdnip/src/main/java/org/onlab/onos/sdnip/SdnIp.java
+++ b/apps/sdnip/src/main/java/org/onlab/onos/sdnip/SdnIp.java
@@ -30,6 +30,7 @@
 import org.onlab.onos.net.host.HostService;
 import org.onlab.onos.net.intent.IntentService;
 import org.onlab.onos.sdnip.bgp.BgpRouteEntry;
+import org.onlab.onos.sdnip.bgp.BgpSession;
 import org.onlab.onos.sdnip.bgp.BgpSessionManager;
 import org.onlab.onos.sdnip.config.SdnIpConfigReader;
 import org.slf4j.Logger;
@@ -97,6 +98,11 @@
     }
 
     @Override
+    public Collection<BgpSession> getBgpSessions() {
+        return bgpSessionManager.getBgpSessions();
+    }
+
+    @Override
     public Collection<BgpRouteEntry> getBgpRoutes() {
         return bgpSessionManager.getBgpRoutes();
     }
diff --git a/apps/sdnip/src/main/java/org/onlab/onos/sdnip/SdnIpService.java b/apps/sdnip/src/main/java/org/onlab/onos/sdnip/SdnIpService.java
index 936b7e8..8503bee 100644
--- a/apps/sdnip/src/main/java/org/onlab/onos/sdnip/SdnIpService.java
+++ b/apps/sdnip/src/main/java/org/onlab/onos/sdnip/SdnIpService.java
@@ -18,12 +18,20 @@
 import java.util.Collection;
 
 import org.onlab.onos.sdnip.bgp.BgpRouteEntry;
+import org.onlab.onos.sdnip.bgp.BgpSession;
 
 /**
  * Service interface exported by SDN-IP.
  */
 public interface SdnIpService {
     /**
+     * Gets the BGP sessions.
+     *
+     * @return the BGP sessions
+     */
+    public Collection<BgpSession> getBgpSessions();
+
+    /**
      * Gets the BGP routes.
      *
      * @return the BGP routes
diff --git a/apps/sdnip/src/main/java/org/onlab/onos/sdnip/cli/BgpNeighborsListCommand.java b/apps/sdnip/src/main/java/org/onlab/onos/sdnip/cli/BgpNeighborsListCommand.java
new file mode 100644
index 0000000..d8fe15a
--- /dev/null
+++ b/apps/sdnip/src/main/java/org/onlab/onos/sdnip/cli/BgpNeighborsListCommand.java
@@ -0,0 +1,151 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.onos.sdnip.cli;
+
+import java.util.Collection;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ArrayNode;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import org.apache.karaf.shell.commands.Command;
+import org.apache.karaf.shell.commands.Option;
+import org.onlab.onos.cli.AbstractShellCommand;
+import org.onlab.onos.sdnip.SdnIpService;
+import org.onlab.onos.sdnip.bgp.BgpSession;
+
+/**
+ * Command to show the BGP neighbors.
+ */
+@Command(scope = "onos", name = "bgp-neighbors",
+         description = "Lists the BGP neighbors")
+public class BgpNeighborsListCommand extends AbstractShellCommand {
+    @Option(name = "-n", aliases = "--neighbor",
+            description = "BGP neighbor to display information about",
+            required = false, multiValued = false)
+    private String bgpNeighbor;
+
+    private static final String FORMAT_NEIGHBOR_LINE1 =
+        "BGP neighbor is %s, remote AS %d, local AS %d";
+    private static final String FORMAT_NEIGHBOR_LINE2 =
+        "  Remote router ID %s, IP %s, BGP version %d, Hold time %d";
+    private static final String FORMAT_NEIGHBOR_LINE3 =
+        "  Local router ID %s, IP %s, BGP version %d, Hold time %d";
+
+    @Override
+    protected void execute() {
+        SdnIpService service = get(SdnIpService.class);
+        Collection<BgpSession> bgpSessions = service.getBgpSessions();
+
+        if (bgpNeighbor != null) {
+            // Print a single neighbor (if found)
+            BgpSession foundBgpSession = null;
+            for (BgpSession bgpSession : bgpSessions) {
+                if (bgpSession.getRemoteBgpId().toString().equals(bgpNeighbor)) {
+                    foundBgpSession = bgpSession;
+                    break;
+                }
+            }
+            if (foundBgpSession != null) {
+                printNeighbor(foundBgpSession);
+            } else {
+                print("BGP neighbor %s not found", bgpNeighbor);
+            }
+            return;
+        }
+
+        // Print all neighbors
+        printNeighbors(bgpSessions);
+    }
+
+    /**
+     * Prints all BGP neighbors.
+     *
+     * @param bgpSessions the BGP sessions for the neighbors to print
+     */
+    private void printNeighbors(Collection<BgpSession> bgpSessions) {
+        if (outputJson()) {
+            print("%s", json(bgpSessions));
+        } else {
+            for (BgpSession bgpSession : bgpSessions) {
+                printNeighbor(bgpSession);
+            }
+        }
+    }
+
+    /**
+     * Prints a BGP neighbor.
+     *
+     * @param bgpSession the BGP session for the neighbor to print
+     */
+    private void printNeighbor(BgpSession bgpSession) {
+        print(FORMAT_NEIGHBOR_LINE1,
+              bgpSession.getRemoteBgpId().toString(),
+              bgpSession.getRemoteAs(),
+              bgpSession.getLocalAs());
+        print(FORMAT_NEIGHBOR_LINE2,
+              bgpSession.getRemoteBgpId().toString(),
+              bgpSession.getRemoteAddress().toString(),
+              bgpSession.getRemoteBgpVersion(),
+              bgpSession.getRemoteHoldtime());
+        print(FORMAT_NEIGHBOR_LINE3,
+              bgpSession.getLocalBgpId().toString(),
+              bgpSession.getLocalAddress().toString(),
+              bgpSession.getLocalBgpVersion(),
+              bgpSession.getLocalHoldtime());
+    }
+
+    /**
+     * Produces a JSON array of BGP neighbors.
+     *
+     * @param bgpSessions the BGP sessions with the data
+     * @return JSON array with the neighbors
+     */
+    private JsonNode json(Collection<BgpSession> bgpSessions) {
+        ObjectMapper mapper = new ObjectMapper();
+        ArrayNode result = mapper.createArrayNode();
+
+        for (BgpSession bgpSession : bgpSessions) {
+            result.add(json(mapper, bgpSession));
+        }
+        return result;
+    }
+
+    /**
+     * Produces JSON object for a BGP neighbor.
+     *
+     * @param mapper the JSON object mapper to use
+     * @param bgpSession the BGP session with the data
+     * @return JSON object for the route
+     */
+    private ObjectNode json(ObjectMapper mapper, BgpSession bgpSession) {
+        ObjectNode result = mapper.createObjectNode();
+
+        result.put("remoteAddress", bgpSession.getRemoteAddress().toString());
+        result.put("remoteBgpVersion", bgpSession.getRemoteBgpVersion());
+        result.put("remoteAs", bgpSession.getRemoteAs());
+        result.put("remoteHoldtime", bgpSession.getRemoteHoldtime());
+        result.put("remoteBgpId", bgpSession.getRemoteBgpId().toString());
+        //
+        result.put("localAddress", bgpSession.getLocalAddress().toString());
+        result.put("localBgpVersion", bgpSession.getLocalBgpVersion());
+        result.put("localAs", bgpSession.getLocalAs());
+        result.put("localHoldtime", bgpSession.getLocalHoldtime());
+        result.put("localBgpId", bgpSession.getLocalBgpId().toString());
+
+        return result;
+    }
+}
diff --git a/apps/sdnip/src/main/resources/OSGI-INF/blueprint/shell-config.xml b/apps/sdnip/src/main/resources/OSGI-INF/blueprint/shell-config.xml
index 773ead6..d86f8f4 100644
--- a/apps/sdnip/src/main/resources/OSGI-INF/blueprint/shell-config.xml
+++ b/apps/sdnip/src/main/resources/OSGI-INF/blueprint/shell-config.xml
@@ -17,6 +17,9 @@
 
   <command-bundle xmlns="http://karaf.apache.org/xmlns/shell/v1.1.0">
     <command>
+      <action class="org.onlab.onos.sdnip.cli.BgpNeighborsListCommand"/>
+    </command>
+    <command>
       <action class="org.onlab.onos.sdnip.cli.BgpRoutesListCommand"/>
     </command>
     <command>
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 33830aa..ac671da 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
@@ -61,8 +61,8 @@
 
     // TODO: make these configurable
     private static final int MAX_EVENTS = 100;
-    private static final int MAX_IDLE_MS = 50;
-    private static final int MAX_BATCH_MS = 200;
+    private static final int MAX_IDLE_MS = 5;
+    private static final int MAX_BATCH_MS = 50;
     private static final int MAX_THREADS = 8;
 
     // FIXME: Replace with a system-wide timer instance;
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/cluster/messaging/impl/ClusterCommunicationManager.java b/core/store/dist/src/main/java/org/onlab/onos/store/cluster/messaging/impl/ClusterCommunicationManager.java
index 1e47a00..6de94b4 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/cluster/messaging/impl/ClusterCommunicationManager.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/cluster/messaging/impl/ClusterCommunicationManager.java
@@ -34,10 +34,10 @@
 import org.onlab.onos.store.cluster.messaging.ClusterMessage;
 import org.onlab.onos.store.cluster.messaging.ClusterMessageHandler;
 import org.onlab.onos.store.cluster.messaging.MessageSubject;
-import org.onlab.onos.store.serializers.ClusterMessageSerializer;
 import org.onlab.onos.store.serializers.KryoNamespaces;
 import org.onlab.onos.store.serializers.KryoSerializer;
-import org.onlab.onos.store.serializers.MessageSubjectSerializer;
+import org.onlab.onos.store.serializers.impl.ClusterMessageSerializer;
+import org.onlab.onos.store.serializers.impl.MessageSubjectSerializer;
 import org.onlab.util.KryoNamespace;
 import org.onlab.netty.Endpoint;
 import org.onlab.netty.Message;
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/GossipDeviceStore.java b/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/GossipDeviceStore.java
index 19dc3e3..4665411 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/GossipDeviceStore.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/GossipDeviceStore.java
@@ -59,7 +59,7 @@
 import org.onlab.onos.store.cluster.messaging.MessageSubject;
 import org.onlab.onos.store.impl.Timestamped;
 import org.onlab.onos.store.serializers.KryoSerializer;
-import org.onlab.onos.store.serializers.DistributedStoreSerializers;
+import org.onlab.onos.store.serializers.impl.DistributedStoreSerializers;
 import org.onlab.packet.ChassisId;
 import org.onlab.util.KryoNamespace;
 import org.onlab.util.NewConcurrentHashMap;
@@ -230,9 +230,10 @@
         final Timestamped<DeviceDescription> deltaDesc = new Timestamped<>(deviceDescription, newTimestamp);
         final DeviceEvent event;
         final Timestamped<DeviceDescription> mergedDesc;
-        synchronized (getOrCreateDeviceDescriptionsMap(deviceId)) {
+        final Map<ProviderId, DeviceDescriptions> device = getOrCreateDeviceDescriptionsMap(deviceId);
+        synchronized (device) {
             event = createOrUpdateDeviceInternal(providerId, deviceId, deltaDesc);
-            mergedDesc = getOrCreateDeviceDescriptionsMap(deviceId).get(providerId).getDeviceDesc();
+            mergedDesc = device.get(providerId).getDeviceDesc();
         }
         if (event != null) {
             log.info("Notifying peers of a device update topology event for providerId: {} and deviceId: {}",
@@ -252,10 +253,10 @@
                                     Timestamped<DeviceDescription> deltaDesc) {
 
         // Collection of DeviceDescriptions for a Device
-        Map<ProviderId, DeviceDescriptions> providerDescs
+        Map<ProviderId, DeviceDescriptions> device
             = getOrCreateDeviceDescriptionsMap(deviceId);
 
-        synchronized (providerDescs) {
+        synchronized (device) {
             // locking per device
 
             if (isDeviceRemoved(deviceId, deltaDesc.timestamp())) {
@@ -263,7 +264,7 @@
                 return null;
             }
 
-            DeviceDescriptions descs = getOrCreateProviderDeviceDescriptions(providerDescs, providerId, deltaDesc);
+            DeviceDescriptions descs = getOrCreateProviderDeviceDescriptions(device, providerId, deltaDesc);
 
             final Device oldDevice = devices.get(deviceId);
             final Device newDevice;
@@ -272,7 +273,7 @@
                 deltaDesc.isNewer(descs.getDeviceDesc())) {
                 // on new device or valid update
                 descs.putDeviceDesc(deltaDesc);
-                newDevice = composeDevice(deviceId, providerDescs);
+                newDevice = composeDevice(deviceId, device);
             } else {
                 // outdated event, ignored.
                 return null;
@@ -444,9 +445,10 @@
         final List<DeviceEvent> events;
         final Timestamped<List<PortDescription>> merged;
 
-        synchronized (getOrCreateDeviceDescriptionsMap(deviceId)) {
+        final Map<ProviderId, DeviceDescriptions> device = getOrCreateDeviceDescriptionsMap(deviceId);
+        synchronized (device) {
             events = updatePortsInternal(providerId, deviceId, timestampedInput);
-            final DeviceDescriptions descs = getOrCreateDeviceDescriptionsMap(deviceId).get(providerId);
+            final DeviceDescriptions descs = device.get(providerId);
             List<PortDescription> mergedList =
                     FluentIterable.from(portDescriptions)
                 .transform(new Function<PortDescription, PortDescription>() {
@@ -632,9 +634,10 @@
             = new Timestamped<>(portDescription, newTimestamp);
         final DeviceEvent event;
         final Timestamped<PortDescription> mergedDesc;
-        synchronized (getOrCreateDeviceDescriptionsMap(deviceId)) {
+        final Map<ProviderId, DeviceDescriptions> device = getOrCreateDeviceDescriptionsMap(deviceId);
+        synchronized (device) {
             event = updatePortStatusInternal(providerId, deviceId, deltaDesc);
-            mergedDesc = getOrCreateDeviceDescriptionsMap(deviceId).get(providerId)
+            mergedDesc = device.get(providerId)
                             .getPortDesc(portDescription.portNumber());
         }
         if (event != null) {
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/flow/impl/DistributedFlowRuleStore.java b/core/store/dist/src/main/java/org/onlab/onos/store/flow/impl/DistributedFlowRuleStore.java
index 81f2bfd..f65da3f 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/flow/impl/DistributedFlowRuleStore.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/flow/impl/DistributedFlowRuleStore.java
@@ -75,9 +75,9 @@
 import org.onlab.onos.store.hz.AbstractHazelcastStore;
 import org.onlab.onos.store.hz.SMap;
 import org.onlab.onos.store.serializers.DecodeTo;
-import org.onlab.onos.store.serializers.DistributedStoreSerializers;
 import org.onlab.onos.store.serializers.KryoSerializer;
 import org.onlab.onos.store.serializers.StoreSerializer;
+import org.onlab.onos.store.serializers.impl.DistributedStoreSerializers;
 import org.onlab.util.KryoNamespace;
 import org.slf4j.Logger;
 
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/host/impl/GossipHostStore.java b/core/store/dist/src/main/java/org/onlab/onos/store/host/impl/GossipHostStore.java
index 30a73e0..5353a91 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/host/impl/GossipHostStore.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/host/impl/GossipHostStore.java
@@ -67,8 +67,8 @@
 import org.onlab.onos.store.cluster.messaging.ClusterMessageHandler;
 import org.onlab.onos.store.cluster.messaging.MessageSubject;
 import org.onlab.onos.store.impl.Timestamped;
-import org.onlab.onos.store.serializers.DistributedStoreSerializers;
 import org.onlab.onos.store.serializers.KryoSerializer;
+import org.onlab.onos.store.serializers.impl.DistributedStoreSerializers;
 import org.onlab.packet.IpAddress;
 import org.onlab.packet.MacAddress;
 import org.onlab.packet.VlanId;
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/link/impl/GossipLinkStore.java b/core/store/dist/src/main/java/org/onlab/onos/store/link/impl/GossipLinkStore.java
index 351581d..e82742a 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/link/impl/GossipLinkStore.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/link/impl/GossipLinkStore.java
@@ -55,8 +55,8 @@
 import org.onlab.onos.store.cluster.messaging.ClusterMessageHandler;
 import org.onlab.onos.store.cluster.messaging.MessageSubject;
 import org.onlab.onos.store.impl.Timestamped;
-import org.onlab.onos.store.serializers.DistributedStoreSerializers;
 import org.onlab.onos.store.serializers.KryoSerializer;
+import org.onlab.onos.store.serializers.impl.DistributedStoreSerializers;
 import org.onlab.util.KryoNamespace;
 import org.slf4j.Logger;
 
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/resource/impl/DistributedLinkResourceStore.java b/core/store/dist/src/main/java/org/onlab/onos/store/resource/impl/DistributedLinkResourceStore.java
index ecccd2b..d05620d 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/resource/impl/DistributedLinkResourceStore.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/resource/impl/DistributedLinkResourceStore.java
@@ -73,7 +73,7 @@
      * @param link the target link
      * @return free resources
      */
-    private Set<ResourceAllocation> readOriginalFreeResources(Link link) {
+    private synchronized Set<ResourceAllocation> readOriginalFreeResources(Link link) {
         // TODO read capacity and lambda resources from topology
         Set<ResourceAllocation> allocations = new HashSet<>();
         for (int i = 1; i <= 100; i++) {
@@ -92,7 +92,7 @@
      *         {@link org.onlab.onos.net.resource.BandwidthResourceAllocation} object with 0 bandwidth
      *
      */
-    private BandwidthResourceAllocation getBandwidth(Set<ResourceAllocation> freeRes) {
+    private synchronized BandwidthResourceAllocation getBandwidth(Set<ResourceAllocation> freeRes) {
         for (ResourceAllocation res : freeRes) {
             if (res.type() == ResourceType.BANDWIDTH) {
                 return (BandwidthResourceAllocation) res;
@@ -107,7 +107,7 @@
      * @param link the target link
      * @param allocations the resources to be subtracted
      */
-    private void subtractFreeResources(Link link, LinkResourceAllocations allocations) {
+    private synchronized void subtractFreeResources(Link link, LinkResourceAllocations allocations) {
         // TODO Use lock or version for updating freeResources.
         checkNotNull(link);
         Set<ResourceAllocation> freeRes = new HashSet<>(getFreeResources(link));
@@ -141,7 +141,7 @@
      * @param link the target link
      * @param allocations the resources to be added
      */
-    private void addFreeResources(Link link, LinkResourceAllocations allocations) {
+    private synchronized void addFreeResources(Link link, LinkResourceAllocations allocations) {
         // TODO Use lock or version for updating freeResources.
         Set<ResourceAllocation> freeRes = new HashSet<>(getFreeResources(link));
         Set<ResourceAllocation> addRes = allocations.getResourceAllocation(link);
@@ -167,7 +167,7 @@
     }
 
     @Override
-    public Set<ResourceAllocation> getFreeResources(Link link) {
+    public synchronized Set<ResourceAllocation> getFreeResources(Link link) {
         checkNotNull(link);
         Set<ResourceAllocation> freeRes = freeResources.get(link);
         if (freeRes == null) {
@@ -178,7 +178,7 @@
     }
 
     @Override
-    public void allocateResources(LinkResourceAllocations allocations) {
+    public synchronized void allocateResources(LinkResourceAllocations allocations) {
         checkNotNull(allocations);
         linkResourceAllocationsMap.put(allocations.intendId(), allocations);
         for (Link link : allocations.links()) {
@@ -193,7 +193,7 @@
     }
 
     @Override
-    public void releaseResources(LinkResourceAllocations allocations) {
+    public synchronized void releaseResources(LinkResourceAllocations allocations) {
         checkNotNull(allocations);
         linkResourceAllocationsMap.remove(allocations.intendId());
         for (Link link : allocations.links()) {
@@ -209,13 +209,13 @@
     }
 
     @Override
-    public LinkResourceAllocations getAllocations(IntentId intentId) {
+    public synchronized LinkResourceAllocations getAllocations(IntentId intentId) {
         checkNotNull(intentId);
         return linkResourceAllocationsMap.get(intentId);
     }
 
     @Override
-    public Iterable<LinkResourceAllocations> getAllocations(Link link) {
+    public synchronized Iterable<LinkResourceAllocations> getAllocations(Link link) {
         checkNotNull(link);
         Set<LinkResourceAllocations> result = allocatedResources.get(link);
         if (result == null) {
@@ -225,7 +225,7 @@
     }
 
     @Override
-    public Iterable<LinkResourceAllocations> getAllocations() {
+    public synchronized Iterable<LinkResourceAllocations> getAllocations() {
         return Collections.unmodifiableCollection(linkResourceAllocationsMap.values());
     }
 
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/serializers/ClusterMessageSerializer.java b/core/store/dist/src/main/java/org/onlab/onos/store/serializers/impl/ClusterMessageSerializer.java
similarity index 97%
rename from core/store/dist/src/main/java/org/onlab/onos/store/serializers/ClusterMessageSerializer.java
rename to core/store/dist/src/main/java/org/onlab/onos/store/serializers/impl/ClusterMessageSerializer.java
index 9cc7f8a..d3f31bb 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/serializers/ClusterMessageSerializer.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/serializers/impl/ClusterMessageSerializer.java
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.onlab.onos.store.serializers;
+package org.onlab.onos.store.serializers.impl;
 
 import org.onlab.onos.cluster.NodeId;
 import org.onlab.onos.store.cluster.messaging.ClusterMessage;
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/serializers/DistributedStoreSerializers.java b/core/store/dist/src/main/java/org/onlab/onos/store/serializers/impl/DistributedStoreSerializers.java
similarity index 92%
rename from core/store/dist/src/main/java/org/onlab/onos/store/serializers/DistributedStoreSerializers.java
rename to core/store/dist/src/main/java/org/onlab/onos/store/serializers/impl/DistributedStoreSerializers.java
index d2de5ad..2de47bd 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/serializers/DistributedStoreSerializers.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/serializers/impl/DistributedStoreSerializers.java
@@ -13,11 +13,12 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.onlab.onos.store.serializers;
+package org.onlab.onos.store.serializers.impl;
 
 import org.onlab.onos.store.impl.MastershipBasedTimestamp;
 import org.onlab.onos.store.impl.Timestamped;
 import org.onlab.onos.store.impl.WallClockTimestamp;
+import org.onlab.onos.store.serializers.KryoNamespaces;
 import org.onlab.util.KryoNamespace;
 
 public final class DistributedStoreSerializers {
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/serializers/MastershipBasedTimestampSerializer.java b/core/store/dist/src/main/java/org/onlab/onos/store/serializers/impl/MastershipBasedTimestampSerializer.java
similarity index 97%
rename from core/store/dist/src/main/java/org/onlab/onos/store/serializers/MastershipBasedTimestampSerializer.java
rename to core/store/dist/src/main/java/org/onlab/onos/store/serializers/impl/MastershipBasedTimestampSerializer.java
index 4221d57..83bff3c 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/serializers/MastershipBasedTimestampSerializer.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/serializers/impl/MastershipBasedTimestampSerializer.java
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.onlab.onos.store.serializers;
+package org.onlab.onos.store.serializers.impl;
 
 import org.onlab.onos.store.impl.MastershipBasedTimestamp;
 
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/serializers/MessageSubjectSerializer.java b/core/store/dist/src/main/java/org/onlab/onos/store/serializers/impl/MessageSubjectSerializer.java
similarity index 96%
rename from core/store/dist/src/main/java/org/onlab/onos/store/serializers/MessageSubjectSerializer.java
rename to core/store/dist/src/main/java/org/onlab/onos/store/serializers/impl/MessageSubjectSerializer.java
index e94d302..1173165 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/serializers/MessageSubjectSerializer.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/serializers/impl/MessageSubjectSerializer.java
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.onlab.onos.store.serializers;
+package org.onlab.onos.store.serializers.impl;
 
 import org.onlab.onos.store.cluster.messaging.MessageSubject;
 
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/ClusterMessagingProtocolClient.java b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/ClusterMessagingProtocolClient.java
index 976fbcf..bb6bfcf 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/ClusterMessagingProtocolClient.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/ClusterMessagingProtocolClient.java
@@ -85,7 +85,7 @@
         return CompletableFuture.completedFuture(null);
     }
 
-    public <I> MessageSubject messageType(I input) {
+    private <I> MessageSubject messageType(I input) {
         Class<?> clazz = input.getClass();
         if (clazz.equals(PollRequest.class)) {
             return ClusterMessagingProtocol.COPYCAT_POLL;
@@ -117,7 +117,7 @@
             this.request = request;
             this.message =
                     new ClusterMessage(
-                            null,
+                            null, // FIXME fill in proper sender
                             messageType(request),
                             ClusterMessagingProtocol.SERIALIZER.encode(request));
             this.future = future;
@@ -132,19 +132,20 @@
                 future.complete(ClusterMessagingProtocol.SERIALIZER.decode(response));
 
             } catch (IOException | InterruptedException | ExecutionException | TimeoutException e) {
-                if (message.subject().equals(ClusterMessagingProtocol.COPYCAT_SYNC) ||
-                        message.subject().equals(ClusterMessagingProtocol.COPYCAT_PING)) {
-                    log.warn("{} Request to {} failed. Will retry in {} ms",
-                             message.subject(), remoteNode, RETRY_INTERVAL_MILLIS);
-                    THREAD_POOL.schedule(
-                            this,
-                            RETRY_INTERVAL_MILLIS,
-                            TimeUnit.MILLISECONDS);
-                } else {
+//                if (message.subject().equals(ClusterMessagingProtocol.COPYCAT_SYNC) ||
+//                        message.subject().equals(ClusterMessagingProtocol.COPYCAT_PING)) {
+//                    log.warn("{} Request to {} failed. Will retry in {} ms",
+//                             message.subject(), remoteNode, RETRY_INTERVAL_MILLIS);
+//                    THREAD_POOL.schedule(
+//                            this,
+//                            RETRY_INTERVAL_MILLIS,
+//                            TimeUnit.MILLISECONDS);
+//                } else {
                     log.warn("RPCTask for {} failed.", request, e);
                     future.completeExceptionally(e);
-                }
+//                }
             } catch (Exception e) {
+                log.warn("RPCTask for {} terribly failed.", request, e);
                 future.completeExceptionally(e);
             }
         }
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/ClusterMessagingProtocolServer.java b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/ClusterMessagingProtocolServer.java
index e2c06c7..a5f207e 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/ClusterMessagingProtocolServer.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/service/impl/ClusterMessagingProtocolServer.java
@@ -67,14 +67,36 @@
         @Override
         public void handle(ClusterMessage message) {
             T request = ClusterMessagingProtocol.SERIALIZER.decode(message.payload());
+            if (handler == null) {
+                // there is a slight window of time during state transition,
+                // where handler becomes null
+                for (int i = 0; i < 10; ++i) {
+                    if (handler != null) {
+                        break;
+                    }
+                    try {
+                        Thread.sleep(1);
+                    } catch (InterruptedException e) {
+                        log.trace("Exception", e);
+                    }
+                }
+                if (handler == null) {
+                    log.error("There was no handler for registered!");
+                    return;
+                }
+            }
             if (request.getClass().equals(PingRequest.class)) {
-                handler.ping((PingRequest) request).whenComplete(new PostExecutionTask<PingResponse>(message));
+                handler.ping((PingRequest) request)
+                    .whenComplete(new PostExecutionTask<PingResponse>(message));
             } else if (request.getClass().equals(PollRequest.class)) {
-                handler.poll((PollRequest) request).whenComplete(new PostExecutionTask<PollResponse>(message));
+                handler.poll((PollRequest) request)
+                    .whenComplete(new PostExecutionTask<PollResponse>(message));
             } else if (request.getClass().equals(SyncRequest.class)) {
-                handler.sync((SyncRequest) request).whenComplete(new PostExecutionTask<SyncResponse>(message));
+                handler.sync((SyncRequest) request)
+                    .whenComplete(new PostExecutionTask<SyncResponse>(message));
             } else if (request.getClass().equals(SubmitRequest.class)) {
-                handler.submit((SubmitRequest) request).whenComplete(new PostExecutionTask<SubmitResponse>(message));
+                handler.submit((SubmitRequest) request)
+                    .whenComplete(new PostExecutionTask<SubmitResponse>(message));
             } else {
                 throw new IllegalStateException("Unknown request type: " + request.getClass().getName());
             }
@@ -94,6 +116,7 @@
                     log.error("Processing for " + message.subject() + " failed.", t);
                 } else {
                     try {
+                        log.trace("responding to {}", message.subject());
                         message.respond(ClusterMessagingProtocol.SERIALIZER.encode(response));
                     } catch (Exception e) {
                         log.error("Failed to respond to " + response.getClass().getName(), e);
diff --git a/core/store/dist/src/test/java/org/onlab/onos/store/impl/MastershipBasedTimestampTest.java b/core/store/dist/src/test/java/org/onlab/onos/store/impl/MastershipBasedTimestampTest.java
index 0060d44..e1da794 100644
--- a/core/store/dist/src/test/java/org/onlab/onos/store/impl/MastershipBasedTimestampTest.java
+++ b/core/store/dist/src/test/java/org/onlab/onos/store/impl/MastershipBasedTimestampTest.java
@@ -21,7 +21,7 @@
 
 import org.junit.Test;
 import org.onlab.onos.store.Timestamp;
-import org.onlab.onos.store.serializers.MastershipBasedTimestampSerializer;
+import org.onlab.onos.store.serializers.impl.MastershipBasedTimestampSerializer;
 import org.onlab.util.KryoNamespace;
 
 import com.google.common.testing.EqualsTester;
diff --git a/core/store/trivial/src/main/java/org/onlab/onos/store/trivial/impl/SimpleLinkResourceStore.java b/core/store/trivial/src/main/java/org/onlab/onos/store/trivial/impl/SimpleLinkResourceStore.java
index 5369375..78cd341 100644
--- a/core/store/trivial/src/main/java/org/onlab/onos/store/trivial/impl/SimpleLinkResourceStore.java
+++ b/core/store/trivial/src/main/java/org/onlab/onos/store/trivial/impl/SimpleLinkResourceStore.java
@@ -73,7 +73,7 @@
      * @param link the target link
      * @return free resources
      */
-    private Set<ResourceAllocation> readOriginalFreeResources(Link link) {
+    private synchronized Set<ResourceAllocation> readOriginalFreeResources(Link link) {
         // TODO read capacity and lambda resources from topology
         Set<ResourceAllocation> allocations = new HashSet<>();
         for (int i = 1; i <= 100; i++) {
@@ -92,7 +92,7 @@
      *         {@link BandwidthResourceAllocation} object with 0 bandwidth
      *
      */
-    private BandwidthResourceAllocation getBandwidth(Set<ResourceAllocation> freeRes) {
+    private synchronized BandwidthResourceAllocation getBandwidth(Set<ResourceAllocation> freeRes) {
         for (ResourceAllocation res : freeRes) {
             if (res.type() == ResourceType.BANDWIDTH) {
                 return (BandwidthResourceAllocation) res;
@@ -107,7 +107,7 @@
      * @param link the target link
      * @param allocations the resources to be subtracted
      */
-    private void subtractFreeResources(Link link, LinkResourceAllocations allocations) {
+    private synchronized void subtractFreeResources(Link link, LinkResourceAllocations allocations) {
         // TODO Use lock or version for updating freeResources.
         checkNotNull(link);
         Set<ResourceAllocation> freeRes = new HashSet<>(getFreeResources(link));
@@ -141,7 +141,7 @@
      * @param link the target link
      * @param allocations the resources to be added
      */
-    private void addFreeResources(Link link, LinkResourceAllocations allocations) {
+    private synchronized void addFreeResources(Link link, LinkResourceAllocations allocations) {
         // TODO Use lock or version for updating freeResources.
         Set<ResourceAllocation> freeRes = new HashSet<>(getFreeResources(link));
         Set<ResourceAllocation> addRes = allocations.getResourceAllocation(link);
@@ -167,7 +167,7 @@
     }
 
     @Override
-    public Set<ResourceAllocation> getFreeResources(Link link) {
+    public synchronized Set<ResourceAllocation> getFreeResources(Link link) {
         checkNotNull(link);
         Set<ResourceAllocation> freeRes = freeResources.get(link);
         if (freeRes == null) {
@@ -178,7 +178,7 @@
     }
 
     @Override
-    public void allocateResources(LinkResourceAllocations allocations) {
+    public synchronized void allocateResources(LinkResourceAllocations allocations) {
         checkNotNull(allocations);
         linkResourceAllocationsMap.put(allocations.intendId(), allocations);
         for (Link link : allocations.links()) {
@@ -193,7 +193,7 @@
     }
 
     @Override
-    public void releaseResources(LinkResourceAllocations allocations) {
+    public synchronized void releaseResources(LinkResourceAllocations allocations) {
         checkNotNull(allocations);
         linkResourceAllocationsMap.remove(allocations.intendId());
         for (Link link : allocations.links()) {
@@ -209,13 +209,13 @@
     }
 
     @Override
-    public LinkResourceAllocations getAllocations(IntentId intentId) {
+    public synchronized LinkResourceAllocations getAllocations(IntentId intentId) {
         checkNotNull(intentId);
         return linkResourceAllocationsMap.get(intentId);
     }
 
     @Override
-    public Iterable<LinkResourceAllocations> getAllocations(Link link) {
+    public synchronized Iterable<LinkResourceAllocations> getAllocations(Link link) {
         checkNotNull(link);
         Set<LinkResourceAllocations> result = allocatedResources.get(link);
         if (result == null) {
@@ -225,7 +225,7 @@
     }
 
     @Override
-    public Iterable<LinkResourceAllocations> getAllocations() {
+    public synchronized Iterable<LinkResourceAllocations> getAllocations() {
         return Collections.unmodifiableCollection(linkResourceAllocationsMap.values());
     }
 
diff --git a/utils/netty/src/main/java/org/onlab/netty/NettyMessagingService.java b/utils/netty/src/main/java/org/onlab/netty/NettyMessagingService.java
index 54b02de..5b7266e 100644
--- a/utils/netty/src/main/java/org/onlab/netty/NettyMessagingService.java
+++ b/utils/netty/src/main/java/org/onlab/netty/NettyMessagingService.java
@@ -315,7 +315,11 @@
                 return;
             }
             MessageHandler handler = NettyMessagingService.this.getMessageHandler(type);
-            handler.handle(message);
+            if (handler != null) {
+                handler.handle(message);
+            } else {
+                log.debug("No handler registered for {}", type);
+            }
         }
 
         @Override