diff --git a/src/main/java/net/onrc/onos/registry/controller/ZookeeperRegistry.java b/src/main/java/net/onrc/onos/registry/controller/ZookeeperRegistry.java
new file mode 100644
index 0000000..58b8bc7
--- /dev/null
+++ b/src/main/java/net/onrc/onos/registry/controller/ZookeeperRegistry.java
@@ -0,0 +1,487 @@
+package net.onrc.onos.registry.controller;
+
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import net.floodlightcontroller.core.module.FloodlightModuleContext;
+import net.floodlightcontroller.core.module.FloodlightModuleException;
+import net.floodlightcontroller.core.module.IFloodlightModule;
+import net.floodlightcontroller.core.module.IFloodlightService;
+import net.floodlightcontroller.restserver.IRestApiService;
+
+import org.apache.zookeeper.CreateMode;
+import org.apache.zookeeper.WatchedEvent;
+import org.apache.zookeeper.Watcher.Event.KeeperState;
+import org.openflow.util.HexString;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.netflix.curator.RetryPolicy;
+import com.netflix.curator.framework.CuratorFramework;
+import com.netflix.curator.framework.CuratorFrameworkFactory;
+import com.netflix.curator.framework.api.CuratorWatcher;
+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;
+import com.netflix.curator.framework.recipes.cache.PathChildrenCacheEvent;
+import com.netflix.curator.framework.recipes.cache.PathChildrenCacheListener;
+import com.netflix.curator.framework.recipes.leader.LeaderLatch;
+import com.netflix.curator.framework.recipes.leader.Participant;
+import com.netflix.curator.retry.ExponentialBackoffRetry;
+
+public class ZookeeperRegistry implements IFloodlightModule, IControllerRegistryService {
+
+	protected static Logger log = LoggerFactory.getLogger(ZookeeperRegistry.class);
+	protected String controllerId = null;
+	
+	protected IRestApiService restApi;
+	
+	//TODO read this from configuration
+	protected String connectionString = "localhost:2181";
+	
+	
+	private final String namespace = "onos";
+	private final String switchLatchesPath = "/switches";
+	private final String controllerPath = "/controllers";
+	
+	protected CuratorFramework client;
+	
+	protected PathChildrenCache controllerCache;
+	protected PathChildrenCache switchCache;
+
+	protected Map<String, LeaderLatch> switchLatches;
+	protected Map<String, ControlChangeCallback> switchCallbacks;
+	protected Map<String, PathChildrenCache> switchPathCaches;
+	
+	//protected boolean zookeeperEnabled = false;
+	
+	protected class ParamaterizedCuratorWatcher implements CuratorWatcher {
+		private String dpid;
+		private boolean isLeader = false;
+		private String latchPath;
+		
+		public ParamaterizedCuratorWatcher(String dpid, String latchPath){
+			this.dpid = dpid;
+			this.latchPath = latchPath;
+		}
+		
+		@Override
+		public synchronized void process(WatchedEvent event) throws Exception {
+			log.debug("Watch Event: {}", event);
+
+			LeaderLatch latch = switchLatches.get(dpid);
+			
+			if (event.getState() == KeeperState.Disconnected){
+				if (isLeader) {
+					log.debug("Disconnected while leader - lost leadership for {}", dpid);
+					
+					isLeader = false;
+					ControlChangeCallback cb = switchCallbacks.get(dpid);
+					if (cb != null) {
+						//Allow callback to be null if the requester doesn't want a callback
+						cb.controlChanged(HexString.toLong(dpid), false);
+					}
+				}
+				return;
+			}
+			
+			try {
+				
+				Participant leader = latch.getLeader();
+
+				if (leader.getId().equals(controllerId) && !isLeader){
+					log.debug("Became leader for {}", dpid);
+					
+					isLeader = true;
+					switchCallbacks.get(dpid).controlChanged(HexString.toLong(dpid), true);
+				}
+				else if (!leader.getId().equals(controllerId) && isLeader){
+					log.debug("Lost leadership for {}", dpid);
+					
+					isLeader = false;
+					switchCallbacks.get(dpid).controlChanged(HexString.toLong(dpid), false);
+				}
+			} catch (Exception e){
+				if (isLeader){
+					log.debug("Exception checking leadership status. Assume leadship lost for {}",
+							dpid);
+					
+					isLeader = false;
+					switchCallbacks.get(dpid).controlChanged(HexString.toLong(dpid), false);
+				}
+			}
+			
+			client.getChildren().usingWatcher(this).inBackground().forPath(latchPath);
+			//client.getChildren().usingWatcher(this).forPath(latchPath);
+		}
+	}
+	
+	
+	/*
+	 * Listens for changes to the switch znodes in Zookeeper. This maintains the second level of
+	 * PathChildrenCaches that hold the controllers contending for each switch - there's one for
+	 * each switch.
+	 */
+	PathChildrenCacheListener switchPathCacheListener = new PathChildrenCacheListener() {
+		@Override
+		public void childEvent(CuratorFramework client,
+				PathChildrenCacheEvent event) throws Exception {
+			// TODO Auto-generated method stub
+			log.debug("Root switch path cache got {} event", event.getType());
+			
+			String strSwitch = null;
+			if (event.getData() != null){
+				log.debug("Event path {}", event.getData().getPath());
+				String[] splitted = event.getData().getPath().split("/");
+				strSwitch = splitted[splitted.length - 1];
+				log.debug("Switch name is {}", strSwitch);
+			}
+			
+			switch (event.getType()){
+			case CHILD_ADDED:
+			case CHILD_UPDATED:
+				//Check we have a PathChildrenCache for this child, add one if not
+				if (switchPathCaches.get(strSwitch) == null){
+					PathChildrenCache pc = new PathChildrenCache(client, 
+							event.getData().getPath(), true);
+					pc.start(StartMode.NORMAL);
+					switchPathCaches.put(strSwitch, pc);
+				}
+				break;
+			case CHILD_REMOVED:
+				//Remove our PathChildrenCache for this child
+				PathChildrenCache pc = switchPathCaches.remove(strSwitch);
+				pc.close();
+				break;
+			default:
+				//All other events are connection status events. We need to do anything
+				//as the path cache handles these on its own.
+				break;
+			}
+			
+		}
+	};
+
+	
+	@Override
+	public void requestControl(long dpid, ControlChangeCallback cb) throws RegistryException {
+		/*
+		if (!zookeeperEnabled) {
+			//If zookeeper connection is disabled all control requests succeed immediately
+			if (cb != null){
+				cb.controlChanged(dpid, true);
+			}
+			return;
+		}*/
+		
+		if (controllerId == null){
+			throw new RuntimeException("Must register a controller before calling requestControl");
+		}
+		
+		String dpidStr = HexString.toHexString(dpid);
+		String latchPath = switchLatchesPath + "/" + dpidStr;
+		
+		if (switchLatches.get(dpidStr) != null){
+			throw new RuntimeException("Leader election for switch " + dpidStr +
+					"is already running");
+		}
+		
+		LeaderLatch latch = new LeaderLatch(client, latchPath, controllerId);
+		switchLatches.put(dpidStr, latch);
+		switchCallbacks.put(dpidStr, cb);
+		
+		try {
+			//client.getChildren().usingWatcher(watcher).inBackground().forPath(singleLatchPath);
+			client.getChildren().usingWatcher(
+					new ParamaterizedCuratorWatcher(dpidStr, latchPath))
+					.inBackground().forPath(latchPath);
+			latch.start();
+		} catch (Exception e) {
+			log.warn("Error starting leader latch: {}", e.getMessage());
+			throw new RegistryException("Error starting leader latch for " + dpidStr, e);
+		}
+		
+	}
+
+	@Override
+	public void releaseControl(long dpid) {
+		//if (!zookeeperEnabled) return;
+		
+		String dpidStr = HexString.toHexString(dpid);
+		
+		LeaderLatch latch = switchLatches.get(dpidStr);
+		if (latch == null) {
+			log.debug("Trying to release mastership for switch we are not contesting");
+			return;
+		}
+		
+		try {
+			latch.close();
+		} catch (IOException e) {
+			//I think it's OK not to do anything here. Either the node got deleted correctly,
+			//or the connection went down and the node got deleted.
+		} finally {
+			switchLatches.remove(dpidStr);
+			switchCallbacks.remove(dpidStr);
+		}
+	}
+
+	@Override
+	public boolean hasControl(long dpid) {
+		//if (!zookeeperEnabled) return false;
+		
+		LeaderLatch latch = switchLatches.get(HexString.toHexString(dpid));
+		
+		if (latch == null) {
+			log.warn("No leader latch for dpid {}", HexString.toHexString(dpid));
+			return false;
+		}
+		
+		try {
+			return latch.getLeader().getId().equals(controllerId);
+		} catch (Exception e) {
+			//TODO swallow exception?
+			return false;
+		}
+	}
+
+	@Override
+	public void setMastershipId(String id) {
+		//TODO remove this method if not needed
+		//controllerId = id;
+	}
+
+	@Override
+	public String getMastershipId() {
+		return controllerId;
+	}
+	
+	@Override
+	public Collection<String> getAllControllers() throws RegistryException {
+		//if (!zookeeperEnabled) return null;
+		
+		log.debug("Getting all controllers");
+		
+		List<String> controllers = new ArrayList<String>();
+		for (ChildData data : controllerCache.getCurrentData()){
+
+			String d = null;
+			try {
+				d = new String(data.getData(), "UTF-8");
+			} catch (UnsupportedEncodingException e) {
+				throw new RegistryException("Error encoding string", e);
+			}
+
+			controllers.add(d);
+		}
+		return controllers;
+	}
+
+	@Override
+	public void registerController(String id) throws RegistryException {
+		//if (!zookeeperEnabled) return;
+		
+		controllerId = id;
+		
+		byte bytes[] = null;
+		try {
+			bytes = id.getBytes("UTF-8");
+		} catch (UnsupportedEncodingException e1) {
+			throw new RegistryException("Error encoding string", e1);
+		}
+		
+		String path = controllerPath + "/" + id;
+		
+		log.info("Registering controller with id {}", id);
+		
+		//Create ephemeral node in controller registry
+		try {
+			client.create().withProtection().withMode(CreateMode.EPHEMERAL)
+					.forPath(path, bytes);
+		} catch (Exception e) {
+			throw new RegistryException("Error contacting the Zookeeper service", e);
+		}
+	}
+	
+	@Override
+	public String getControllerForSwitch(long dpid) throws RegistryException {
+		//if (!zookeeperEnabled) return null;
+		// TODO Work out how we should store this controller/switch data.
+		// The leader latch might be a index to the /controllers collections
+		// which holds more info on the controller (how to talk to it for example).
+		
+		
+		String strDpid = HexString.toHexString(dpid);
+		LeaderLatch latch = switchLatches.get(strDpid);
+		
+		if (latch == null){
+			log.warn("Tried to get controller for non-existent switch");
+			return null;
+		}
+		
+		Participant leader = null;
+		try {
+			leader = latch.getLeader();
+		} catch (Exception e) {
+			throw new RegistryException("Error contacting the Zookeeper service", e);
+		}
+		
+		return leader.getId();
+	}
+	
+	@Override
+	public Collection<Long> getSwitchesControlledByController(String controllerId) {
+		//TODO remove this if not needed
+		throw new RuntimeException("Not yet implemented");
+	}
+	
+
+	@Override
+	public Map<String, List<ControllerRegistryEntry>> getAllSwitches() {
+		Map<String, List<ControllerRegistryEntry>> data = 
+				new HashMap<String, List<ControllerRegistryEntry>>();
+		
+		for (Map.Entry<String, PathChildrenCache> entry : switchPathCaches.entrySet()){
+			List<ControllerRegistryEntry> contendingControllers =
+					 new ArrayList<ControllerRegistryEntry>(); 
+			
+			if (entry.getValue().getCurrentData().size() < 1){
+				log.info("Switch entry with no leader elections: {}", entry.getKey());
+				continue;
+			}
+			
+			for (ChildData d : entry.getValue().getCurrentData()) {
+				/*
+				if (d.getPath().length() < 1){
+					log.info("Switch entry with no leader elections: {}", d.getPath());
+					continue;
+				}
+				*/
+				
+				String controllerId = null;
+				try {
+					controllerId = new String(d.getData(), "UTF-8");
+				} catch (UnsupportedEncodingException e) {
+					log.warn("Encoding exception: {}", e.getMessage());
+				}
+				
+				String[] splitted = d.getPath().split("-");
+				int sequenceNumber = Integer.parseInt(splitted[splitted.length - 1]);
+				
+				contendingControllers.add(new ControllerRegistryEntry(controllerId, sequenceNumber));
+			 }
+			
+			Collections.sort(contendingControllers);
+			data.put(entry.getKey(), contendingControllers);
+		}
+		return data;
+	}
+	
+	/*
+	 * IFloodlightModule
+	 */
+	
+	@Override
+	public Collection<Class<? extends IFloodlightService>> getModuleServices() {
+		Collection<Class<? extends IFloodlightService>> l = 
+				new ArrayList<Class<? extends IFloodlightService>>();
+		l.add(IControllerRegistryService.class);
+		return l;
+	}
+	
+	@Override
+	public Map<Class<? extends IFloodlightService>, IFloodlightService> getServiceImpls() {
+		Map<Class<? extends IFloodlightService>, IFloodlightService> m = 
+				new HashMap<Class<? extends IFloodlightService>, IFloodlightService>();
+		m.put(IControllerRegistryService.class,  this);
+		return m;
+	}
+	
+	@Override
+	public Collection<Class<? extends IFloodlightService>> getModuleDependencies() {
+		Collection<Class<? extends IFloodlightService>> l =
+                new ArrayList<Class<? extends IFloodlightService>>();
+        l.add(IRestApiService.class);
+		return l;
+	}
+	
+	@Override
+	public void init (FloodlightModuleContext context) throws FloodlightModuleException {
+		
+		log.info("Initialising the Zookeeper Registry - Zookeeper connection required");
+		
+		restApi = context.getServiceImpl(IRestApiService.class);
+		
+		//We have a config option that determines whether we try and connect to 
+		//zookeeper or not. By default zookeeper connection is disabled. When we don't
+		//have a zookeeper connection we act as though we are the only server in the 
+		//cluster, i.e. all control requests will succeed.
+		/*Map<String, String> configOptions = context.getConfigParams(this);
+		String enableZookeeper = configOptions.get("enableZookeeper");
+		if (enableZookeeper != null) {
+			log.info("Enabling Zookeeper connection");
+			zookeeperEnabled = true;
+		}
+		else {
+			log.info("Zookeeper connectivity is disabled - running in standalone mode");
+			return;
+		}*/
+		
+		/*
+		try {
+			String localHostname = java.net.InetAddress.getLocalHost().getHostName();
+			controllerId = localHostname;
+			log.debug("Setting controller id to {}", controllerId);
+		} catch (UnknownHostException e) {
+			// TODO Handle this exception
+			e.printStackTrace();
+		}*/
+
+		switchLatches = new HashMap<String, LeaderLatch>();
+		switchCallbacks = new HashMap<String, ControlChangeCallback>();
+		switchPathCaches = new HashMap<String, PathChildrenCache>();
+		
+		RetryPolicy retryPolicy = new ExponentialBackoffRetry(1000, 3);
+		client = CuratorFrameworkFactory.newClient(connectionString, retryPolicy);
+		
+		client.start();
+		
+		client = client.usingNamespace(namespace);
+		
+		//Put some data in for testing
+		/*
+		try {
+			registerController("zookeeperController");
+			requestControl(2L, null);
+		} catch (RegistryException e1) {
+			// TODO Auto-generated catch block
+			e1.printStackTrace();
+		}*/
+		
+		controllerCache = new PathChildrenCache(client, controllerPath, true);
+		switchCache = new PathChildrenCache(client, switchLatchesPath, true);
+		switchCache.getListenable().addListener(switchPathCacheListener);
+		
+		try {
+			controllerCache.start(StartMode.BUILD_INITIAL_CACHE);
+			
+			//Don't prime the cache, we want a notification for each child node in the path
+			switchCache.start(StartMode.NORMAL);
+		} catch (Exception e) {
+			// TODO Auto-generated catch block
+			e.printStackTrace();
+		}
+	}
+	
+	@Override
+	public void startUp (FloodlightModuleContext context) {
+		restApi.addRestletRoutable(new RegistryWebRoutable());
+	}
+
+}