diff --git a/src/main/java/net/floodlightcontroller/flowcache/FlowManager.java b/src/main/java/net/floodlightcontroller/flowcache/FlowManager.java
index 098e02f..3561e19 100644
--- a/src/main/java/net/floodlightcontroller/flowcache/FlowManager.java
+++ b/src/main/java/net/floodlightcontroller/flowcache/FlowManager.java
@@ -32,13 +32,12 @@
 import net.floodlightcontroller.core.module.FloodlightModuleException;
 import net.floodlightcontroller.core.module.IFloodlightModule;
 import net.floodlightcontroller.core.module.IFloodlightService;
-import net.floodlightcontroller.flowcache.IFlowService;
 import net.floodlightcontroller.flowcache.web.FlowWebRoutable;
 import net.floodlightcontroller.restserver.IRestApiService;
 import net.floodlightcontroller.util.CallerId;
 import net.floodlightcontroller.util.DataPath;
-import net.floodlightcontroller.util.Dpid;
 import net.floodlightcontroller.util.DataPathEndpoints;
+import net.floodlightcontroller.util.Dpid;
 import net.floodlightcontroller.util.FlowEntry;
 import net.floodlightcontroller.util.FlowEntryAction;
 import net.floodlightcontroller.util.FlowEntryId;
@@ -53,6 +52,8 @@
 import net.floodlightcontroller.util.Port;
 import net.floodlightcontroller.util.SwitchPort;
 import net.onrc.onos.flow.IFlowManager;
+import net.onrc.onos.registry.controller.IControllerRegistryService;
+import net.onrc.onos.registry.controller.IdBlock;
 import net.onrc.onos.util.GraphDBConnection;
 import net.onrc.onos.util.GraphDBConnection.Transaction;
 
@@ -63,7 +64,6 @@
 import org.openflow.protocol.OFType;
 import org.openflow.protocol.action.OFAction;
 import org.openflow.protocol.action.OFActionOutput;
-
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -74,6 +74,7 @@
     protected IRestApiService restApi;
     protected IFloodlightProviderService floodlightProvider;
     protected ITopoRouteService topoRouteService;
+    protected IControllerRegistryService registryService;
     protected FloodlightModuleContext context;
 
     protected OFMessageDamper messageDamper;
@@ -112,6 +113,9 @@
     private BlockingQueue<Runnable> shortestPathQueue = new LinkedBlockingQueue<Runnable>();
     private ThreadPoolExecutor shortestPathExecutor =
 	new ThreadPoolExecutor(10, 10, 5, TimeUnit.SECONDS, shortestPathQueue);
+    
+    protected IdBlock idBlock = null;
+    protected long nextId = 0;
 
     class ShortestPathTask implements Runnable {
 	private int hint;
@@ -656,11 +660,12 @@
     @Override
     public Collection<Class<? extends IFloodlightService>> 
                                                     getModuleDependencies() {
-	Collection<Class<? extends IFloodlightService>> l =
-	    new ArrayList<Class<? extends IFloodlightService>>();
-	l.add(IFloodlightProviderService.class);
-	l.add(ITopoRouteService.class);
-	l.add(IRestApiService.class);
+		Collection<Class<? extends IFloodlightService>> l =
+		    new ArrayList<Class<? extends IFloodlightService>>();
+		l.add(IFloodlightProviderService.class);
+		l.add(ITopoRouteService.class);
+		l.add(IRestApiService.class);
+		l.add(IControllerRegistryService.class);
         return l;
     }
 
@@ -671,6 +676,7 @@
 	floodlightProvider = context.getServiceImpl(IFloodlightProviderService.class);
 	topoRouteService = context.getServiceImpl(ITopoRouteService.class);
 	restApi = context.getServiceImpl(IRestApiService.class);
+	registryService = context.getServiceImpl(IControllerRegistryService.class);
 	messageDamper = new OFMessageDamper(OFMESSAGE_DAMPER_CAPACITY,
 					    EnumSet.of(OFType.FLOW_MOD),
 					    OFMESSAGE_DAMPER_TIMEOUT);
@@ -699,10 +705,18 @@
 
     @Override
     public void startUp(FloodlightModuleContext context) {
-	restApi.addRestletRoutable(new FlowWebRoutable());
-
-	// Initialize the Flow Entry ID generator
-	nextFlowEntryIdPrefix = randomGenerator.nextInt();
+		restApi.addRestletRoutable(new FlowWebRoutable());
+	
+		// Initialize the Flow Entry ID generator
+		nextFlowEntryIdPrefix = randomGenerator.nextInt();
+		
+		idBlock = registryService.allocateUniqueIdBlock();
+		if (idBlock != null){
+			log.debug("ID block allocated: {}", idBlock);
+		}
+		else{
+			log.error("Null ID block allocated by registry");
+		}
     }
 
     /**
diff --git a/src/main/java/net/onrc/onos/registry/controller/IControllerRegistryService.java b/src/main/java/net/onrc/onos/registry/controller/IControllerRegistryService.java
index dadee65..21da47e 100644
--- a/src/main/java/net/onrc/onos/registry/controller/IControllerRegistryService.java
+++ b/src/main/java/net/onrc/onos/registry/controller/IControllerRegistryService.java
@@ -115,4 +115,7 @@
 	 * @return Collection of dpids
 	 */
 	public Collection<Long> getSwitchesControlledByController(String controllerId);
+	
+	public IdBlock allocateUniqueIdBlock();
+	
 }
diff --git a/src/main/java/net/onrc/onos/registry/controller/IdBlock.java b/src/main/java/net/onrc/onos/registry/controller/IdBlock.java
new file mode 100644
index 0000000..64b2af8
--- /dev/null
+++ b/src/main/java/net/onrc/onos/registry/controller/IdBlock.java
@@ -0,0 +1,31 @@
+package net.onrc.onos.registry.controller;
+
+public class IdBlock {
+	private long start;
+	private long end;
+	private long size;
+	
+	public IdBlock(long start, long end, long size) {
+		this.start = start;
+		this.end = end;
+		this.size = size;
+	}
+	
+	public long getStart() {
+		return start;
+	}
+
+	public long getEnd() {
+		return end;
+	}
+
+	public long getSize() {
+		return size;
+	}
+	
+	@Override
+	public String toString() {
+		return "IdBlock [start=" + start + ", end=" + end + ", size=" + size
+				+ "]";
+	}
+}
diff --git a/src/main/java/net/onrc/onos/registry/controller/StandaloneRegistry.java b/src/main/java/net/onrc/onos/registry/controller/StandaloneRegistry.java
index 2c220fd..e48c519 100644
--- a/src/main/java/net/onrc/onos/registry/controller/StandaloneRegistry.java
+++ b/src/main/java/net/onrc/onos/registry/controller/StandaloneRegistry.java
@@ -115,6 +115,12 @@
 			String controllerId) {
 		throw new RuntimeException("Not yet implemented");
 	}
+	
+	@Override
+	public IdBlock allocateUniqueIdBlock(){
+		//XXX Not exactly unique...
+		return new IdBlock(0L, 0x10000000L, 0x10000000L);
+	}
 
 	@Override
 	public Collection<Class<? extends IFloodlightService>> getModuleServices() {
diff --git a/src/main/java/net/onrc/onos/registry/controller/ZookeeperRegistry.java b/src/main/java/net/onrc/onos/registry/controller/ZookeeperRegistry.java
index 76b7ebd..82259a9 100644
--- a/src/main/java/net/onrc/onos/registry/controller/ZookeeperRegistry.java
+++ b/src/main/java/net/onrc/onos/registry/controller/ZookeeperRegistry.java
@@ -24,6 +24,8 @@
 import com.netflix.curator.RetryPolicy;
 import com.netflix.curator.framework.CuratorFramework;
 import com.netflix.curator.framework.CuratorFrameworkFactory;
+import com.netflix.curator.framework.recipes.atomic.AtomicValue;
+import com.netflix.curator.framework.recipes.atomic.DistributedAtomicLong;
 import com.netflix.curator.framework.recipes.cache.ChildData;
 import com.netflix.curator.framework.recipes.cache.PathChildrenCache;
 import com.netflix.curator.framework.recipes.cache.PathChildrenCache.StartMode;
@@ -33,6 +35,7 @@
 import com.netflix.curator.framework.recipes.leader.LeaderLatchEvent;
 import com.netflix.curator.framework.recipes.leader.LeaderLatchListener;
 import com.netflix.curator.retry.ExponentialBackoffRetry;
+import com.netflix.curator.retry.RetryOneTime;
 import com.netflix.curator.x.discovery.ServiceCache;
 import com.netflix.curator.x.discovery.ServiceDiscovery;
 import com.netflix.curator.x.discovery.ServiceDiscoveryBuilder;
@@ -67,6 +70,10 @@
 	protected ConcurrentHashMap<String, SwitchLeadershipData> switches;
 	protected Map<String, PathChildrenCache> switchPathCaches;
 	
+	private final String ID_COUNTER_PATH = "/flowidcounter";
+	private final Long ID_BLOCK_SIZE = 0x100000000L;
+	protected DistributedAtomicLong distributedIdCounter;
+	
 	//Zookeeper performance-related configuration
 	protected static final int sessionTimeout = 5000;
 	protected static final int connectionTimeout = 7000;
@@ -372,6 +379,21 @@
 		return data;
 	}
 	
+	public IdBlock allocateUniqueIdBlock(){
+		try {
+			AtomicValue<Long> result = null;
+			do {
+				result = distributedIdCounter.add(ID_BLOCK_SIZE);
+			} while (result == null || !result.succeeded());
+			
+			return new IdBlock(result.preValue(), result.postValue() - 1, ID_BLOCK_SIZE);
+		} catch (Exception e) {
+			log.error("Error allocating ID block");
+		} 
+		
+		return null;
+	}
+	
 	/*
 	 * IFloodlightModule
 	 */
@@ -427,6 +449,10 @@
 		client.start();
 		client = client.usingNamespace(namespace);
 
+		distributedIdCounter = new DistributedAtomicLong(
+				client, 
+				ID_COUNTER_PATH, 
+				new RetryOneTime(100));
 		
 		switchCache = new PathChildrenCache(client, switchLatchesPath, true);
 		switchCache.getListenable().addListener(switchPathCacheListener);
diff --git a/titan/listNotUpdated b/titan/listNotUpdated
new file mode 100644
index 0000000..a44c458
--- /dev/null
+++ b/titan/listNotUpdated
@@ -0,0 +1,4 @@
+g.stopTransaction(SUCCESS)
+g.V('type', 'flow_entry').each{
+if (it.switch_state.equals("FE_SWITCH_NOT_UPDATED")) println it.map.next()
+}
\ No newline at end of file