CORD-1071 Refactor VTN node service

Done
- Separated interface, implementation and store for node management
- Added unit tests for node manager and handler
- Offloaded more of the event handling off of the Atomix event thread

Todo
- Add REST interface for the node service

Change-Id: Ibf90d3a621013497cc891ca3086db6648f5d49df
diff --git a/src/main/java/org/opencord/cordvtn/impl/CordVtnArpProxy.java b/src/main/java/org/opencord/cordvtn/impl/CordVtnArpProxy.java
index 4dc69a2..3d0c492 100644
--- a/src/main/java/org/opencord/cordvtn/impl/CordVtnArpProxy.java
+++ b/src/main/java/org/opencord/cordvtn/impl/CordVtnArpProxy.java
@@ -36,10 +36,13 @@
 import org.onosproject.core.CoreService;
 import org.onosproject.net.DeviceId;
 import org.onosproject.net.Host;
+import org.onosproject.net.HostId;
+import org.onosproject.net.Port;
 import org.onosproject.net.PortNumber;
 import org.onosproject.net.config.NetworkConfigEvent;
 import org.onosproject.net.config.NetworkConfigListener;
 import org.onosproject.net.config.NetworkConfigService;
+import org.onosproject.net.device.DeviceService;
 import org.onosproject.net.flow.DefaultTrafficSelector;
 import org.onosproject.net.flow.DefaultTrafficTreatment;
 import org.onosproject.net.flow.TrafficSelector;
@@ -57,6 +60,8 @@
 import org.opencord.cordvtn.api.core.ServiceNetworkListener;
 import org.opencord.cordvtn.api.core.ServiceNetworkService;
 import org.opencord.cordvtn.api.net.ServiceNetwork;
+import org.opencord.cordvtn.api.node.CordVtnNode;
+import org.opencord.cordvtn.api.node.CordVtnNodeService;
 import org.osgi.service.component.ComponentContext;
 import org.slf4j.Logger;
 
@@ -68,6 +73,7 @@
 
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkNotNull;
+import static org.onosproject.net.AnnotationKeys.PORT_NAME;
 import static org.opencord.cordvtn.api.Constants.DEFAULT_GATEWAY_MAC_STR;
 import static org.opencord.cordvtn.api.net.ServiceNetwork.NetworkType.*;
 import static org.slf4j.LoggerFactory.getLogger;
@@ -97,7 +103,10 @@
     protected ComponentConfigService compConfigService;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    protected CordVtnNodeManager nodeManager;
+    protected DeviceService deviceService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected CordVtnNodeService nodeService;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     protected ServiceNetworkService snetService;
@@ -303,13 +312,11 @@
 
     private void forwardManagementArpRequest(PacketContext context, Ethernet ethPacket) {
         DeviceId deviceId = context.inPacket().receivedFrom().deviceId();
-        PortNumber hostMgmtPort = nodeManager.hostManagementPort(deviceId);
-        Host host = hostService.getConnectedHosts(context.inPacket().receivedFrom())
-                .stream()
-                .findFirst().orElse(null);
+        PortNumber hostMgmtPort = hostMgmtPort(deviceId);
+        Host host = hostService.getHost(HostId.hostId(ethPacket.getSourceMAC()));
 
         if (host == null ||
-                !Instance.of(host).netType().name().contains("MANAGEMENT") ||
+                Instance.of(host).netType() != MANAGEMENT_HOST ||
                 hostMgmtPort == null) {
             context.block();
             return;
@@ -324,10 +331,22 @@
                 treatment,
                 ByteBuffer.wrap(ethPacket.serialize())));
 
-        log.trace("Forward ARP request to management network");
         context.block();
     }
 
+    private PortNumber hostMgmtPort(DeviceId deviceId) {
+        CordVtnNode node = nodeService.node(deviceId);
+        if (node == null || node.hostManagementInterface() == null) {
+            return null;
+        }
+        Optional<Port> port = deviceService.getPorts(deviceId).stream()
+                .filter(p -> p.annotations().value(PORT_NAME)
+                        .equals(node.hostManagementInterface()) &&
+                        p.isEnabled())
+                .findAny();
+        return port.isPresent() ? port.get().number() : null;
+    }
+
     /**
      * Emits gratuitous ARP when a gateway mac address has been changed.
      *
@@ -465,7 +484,7 @@
     private void readPublicGateways() {
         CordVtnConfig config = netConfigService.getConfig(appId, CordVtnConfig.class);
         if (config == null) {
-            log.debug("No configuration found");
+            log.warn("No configuration found");
             return;
         }
 
diff --git a/src/main/java/org/opencord/cordvtn/impl/CordVtnNodeManager.java b/src/main/java/org/opencord/cordvtn/impl/CordVtnNodeManager.java
index 97f5f77..14f96ea 100644
--- a/src/main/java/org/opencord/cordvtn/impl/CordVtnNodeManager.java
+++ b/src/main/java/org/opencord/cordvtn/impl/CordVtnNodeManager.java
@@ -16,99 +16,66 @@
 package org.opencord.cordvtn.impl;
 
 import com.google.common.base.Strings;
-import com.google.common.collect.Lists;
-import com.jcraft.jsch.Session;
+import com.google.common.collect.ImmutableSet;
 import org.apache.felix.scr.annotations.Activate;
 import org.apache.felix.scr.annotations.Component;
 import org.apache.felix.scr.annotations.Deactivate;
 import org.apache.felix.scr.annotations.Reference;
 import org.apache.felix.scr.annotations.ReferenceCardinality;
 import org.apache.felix.scr.annotations.Service;
-import org.onlab.packet.IpAddress;
-import org.onlab.util.KryoNamespace;
 import org.onosproject.cluster.ClusterService;
 import org.onosproject.cluster.LeadershipService;
 import org.onosproject.cluster.NodeId;
 import org.onosproject.core.ApplicationId;
 import org.onosproject.core.CoreService;
-import org.onosproject.net.ConnectPoint;
-import org.onosproject.net.Device;
+import org.onosproject.event.ListenerRegistry;
 import org.onosproject.net.DeviceId;
-import org.onosproject.net.Port;
-import org.onosproject.net.PortNumber;
-import org.onosproject.net.behaviour.BridgeConfig;
-import org.onosproject.net.behaviour.BridgeDescription;
-import org.onosproject.net.behaviour.BridgeName;
-import org.onosproject.net.behaviour.ControllerInfo;
-import org.onosproject.net.behaviour.DefaultBridgeDescription;
-import org.onosproject.net.behaviour.DefaultTunnelDescription;
-import org.onosproject.net.behaviour.InterfaceConfig;
-import org.onosproject.net.behaviour.TunnelDescription;
-import org.onosproject.net.behaviour.TunnelEndPoints;
-import org.onosproject.net.behaviour.TunnelKeys;
 import org.onosproject.net.config.NetworkConfigEvent;
 import org.onosproject.net.config.NetworkConfigListener;
 import org.onosproject.net.config.NetworkConfigService;
-import org.onosproject.net.device.DeviceAdminService;
-import org.onosproject.net.device.DeviceEvent;
-import org.onosproject.net.device.DeviceListener;
-import org.onosproject.net.device.DeviceService;
-import org.onosproject.net.host.HostService;
-import org.onosproject.ovsdb.controller.OvsdbClientService;
-import org.onosproject.ovsdb.controller.OvsdbController;
-import org.onosproject.ovsdb.controller.OvsdbNodeId;
-import org.onosproject.store.serializers.KryoNamespaces;
-import org.onosproject.store.service.ConsistentMap;
-import org.onosproject.store.service.MapEvent;
-import org.onosproject.store.service.MapEventListener;
-import org.onosproject.store.service.Serializer;
-import org.onosproject.store.service.StorageService;
-import org.onosproject.store.service.Versioned;
 import org.opencord.cordvtn.api.CordVtnConfig;
-import org.opencord.cordvtn.api.core.InstanceService;
-import org.opencord.cordvtn.api.net.CidrAddr;
-import org.opencord.cordvtn.api.node.ConnectionHandler;
 import org.opencord.cordvtn.api.node.CordVtnNode;
-import org.opencord.cordvtn.api.node.CordVtnNodeState;
-import org.opencord.cordvtn.api.node.SshAccessInfo;
+import org.opencord.cordvtn.api.node.CordVtnNodeAdminService;
+import org.opencord.cordvtn.api.node.CordVtnNodeEvent;
+import org.opencord.cordvtn.api.node.CordVtnNodeListener;
+import org.opencord.cordvtn.api.node.CordVtnNodeService;
+import org.opencord.cordvtn.api.node.CordVtnNodeStore;
+import org.opencord.cordvtn.api.node.CordVtnNodeStoreDelegate;
 import org.slf4j.Logger;
 
-import java.util.List;
 import java.util.Objects;
-import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.ExecutorService;
 import java.util.stream.Collectors;
 
+import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkNotNull;
+import static java.lang.String.format;
 import static java.util.concurrent.Executors.newSingleThreadExecutor;
 import static org.onlab.util.Tools.groupedThreads;
-import static org.onosproject.net.AnnotationKeys.PORT_NAME;
-import static org.onosproject.net.Device.Type.SWITCH;
-import static org.onosproject.net.behaviour.TunnelDescription.Type.VXLAN;
 import static org.opencord.cordvtn.api.Constants.*;
-import static org.opencord.cordvtn.impl.RemoteIpCommandUtil.*;
+import static org.opencord.cordvtn.api.node.CordVtnNodeState.*;
 import static org.slf4j.LoggerFactory.getLogger;
 
 /**
- * Reads node information from the network config file and handles the config
- * update events.
- * Only a leader controller performs the node addition or deletion.
+ * Manages the inventory of the cordvtn nodes provided via network configuration.
  */
 @Component(immediate = true)
-@Service(value = CordVtnNodeManager.class)
-public class CordVtnNodeManager {
+@Service
+public class CordVtnNodeManager extends ListenerRegistry<CordVtnNodeEvent, CordVtnNodeListener>
+        implements CordVtnNodeAdminService, CordVtnNodeService {
 
     protected final Logger log = getLogger(getClass());
 
-    private static final KryoNamespace.Builder NODE_SERIALIZER = KryoNamespace.newBuilder()
-            .register(KryoNamespaces.API)
-            .register(CordVtnNode.class)
-            .register(NodeState.class)
-            .register(SshAccessInfo.class)
-            .register(CidrAddr.class);
+    private static final String MSG_NODE  = "Node %s %s";
+    private static final String MSG_CREATED = "created";
+    private static final String MSG_UPDATED = "updated";
+    private static final String MSG_REMOVED = "removed";
 
-    private static final int DPID_BEGIN = 3;
+    private static final String ERR_NULL_NODE = "CordVtn node cannot be null";
+    private static final String ERR_NULL_HOSTNAME = "CordVtn node hostname cannot be null";
+    private static final String ERR_NULL_DEVICE_ID = "Device ID cannot be null";
+    private static final String ERR_NOT_FOUND = "does not exist";
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     protected CoreService coreService;
@@ -117,114 +84,32 @@
     protected NetworkConfigService configService;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    protected StorageService storageService;
-
-    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    protected DeviceAdminService adminService;
-
-    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    protected OvsdbController ovsdbController;
+    protected LeadershipService leadershipService;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     protected ClusterService clusterService;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    protected DeviceService deviceService;
+    protected CordVtnNodeStore nodeStore;
 
-    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    protected HostService hostService;
-
-    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    protected LeadershipService leadershipService;
-
-    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    protected InstanceService instanceService;
-
-    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    protected CordVtnPipeline pipeline;
-
-    private final ExecutorService eventExecutor =
-            newSingleThreadExecutor(groupedThreads("onos/cordvtn-node", "event-handler", log));
+    private final ExecutorService eventExecutor = newSingleThreadExecutor(
+            groupedThreads(this.getClass().getSimpleName(), "event-handler", log));
 
     private final NetworkConfigListener configListener = new InternalConfigListener();
-    private final DeviceListener deviceListener = new InternalDeviceListener();
-    private final MapEventListener<String, CordVtnNode> nodeStoreListener = new InternalMapListener();
+    private final CordVtnNodeStoreDelegate delegate = new InternalCordVtnNodeStoreDelegate();
 
-    private final OvsdbHandler ovsdbHandler = new OvsdbHandler();
-    private final BridgeHandler bridgeHandler = new BridgeHandler();
-
-    private ConsistentMap<String, CordVtnNode> nodeStore;
-    private List<ControllerInfo> controllers = Lists.newArrayList();
     private ApplicationId appId;
     private NodeId localNodeId;
 
-    private enum NodeState implements CordVtnNodeState {
-
-        INIT {
-            @Override
-            public void process(CordVtnNodeManager nodeManager, CordVtnNode node) {
-                // make sure there is OVSDB connection
-                if (!nodeManager.isOvsdbConnected(node)) {
-                    nodeManager.connectOvsdb(node);
-                    return;
-                }
-                nodeManager.createIntegrationBridge(node);
-            }
-        },
-        BRIDGE_CREATED {
-            @Override
-            public void process(CordVtnNodeManager nodeManager, CordVtnNode node) {
-                // make sure there is OVSDB connection
-                if (!nodeManager.isOvsdbConnected(node)) {
-                    nodeManager.connectOvsdb(node);
-                    return;
-                }
-
-                nodeManager.createTunnelInterface(node);
-                nodeManager.addSystemInterface(node, node.dataIface());
-                if (node.hostMgmtIface().isPresent()) {
-                    nodeManager.addSystemInterface(node, node.hostMgmtIface().get());
-                }
-            }
-        },
-        PORTS_ADDED {
-            @Override
-            public void process(CordVtnNodeManager nodeManager, CordVtnNode node) {
-                nodeManager.setIpAddress(node);
-            }
-        },
-        COMPLETE {
-            @Override
-            public void process(CordVtnNodeManager nodeManager, CordVtnNode node) {
-                nodeManager.postInit(node);
-            }
-        },
-        INCOMPLETE {
-            @Override
-            public void process(CordVtnNodeManager nodeManager, CordVtnNode node) {
-            }
-        };
-
-        public abstract void process(CordVtnNodeManager nodeManager, CordVtnNode node);
-    }
-
     @Activate
     protected void activate() {
         appId = coreService.registerApplication(CORDVTN_APP_ID);
         leadershipService.runForLeadership(appId.name());
         localNodeId = clusterService.getLocalNode().id();
 
-        nodeStore = storageService.<String, CordVtnNode>consistentMapBuilder()
-                .withSerializer(Serializer.using(NODE_SERIALIZER.build()))
-                .withName("cordvtn-nodestore")
-                .withApplicationId(appId)
-                .build();
-
-        nodeStore.addListener(nodeStoreListener, eventExecutor);
-        deviceService.addListener(deviceListener);
+        nodeStore.setDelegate(delegate);
         configService.addListener(configListener);
 
-        readControllers();
         readNodes();
         log.info("Started");
     }
@@ -232,8 +117,7 @@
     @Deactivate
     protected void deactivate() {
         configService.removeListener(configListener);
-        deviceService.removeListener(deviceListener);
-        nodeStore.removeListener(nodeStoreListener);
+        nodeStore.unsetDelegate(delegate);
 
         leadershipService.withdraw(appId.name());
         eventExecutor.shutdown();
@@ -241,611 +125,60 @@
         log.info("Stopped");
     }
 
-    /**
-     * Adds or updates a new node to the service.
-     *
-     * @param node cordvtn node
-     */
-    public void addOrUpdateNode(CordVtnNode node) {
-        checkNotNull(node);
-        nodeStore.put(node.hostname(), CordVtnNode.getUpdatedNode(node, getNodeState(node)));
+    @Override
+    public void createNode(CordVtnNode node) {
+        checkNotNull(node, ERR_NULL_NODE);
+        nodeStore.createNode(node);
+        log.info(format(MSG_NODE, node.hostname(), MSG_CREATED));
     }
 
-    /**
-     * Deletes a node from the service.
-     *
-     * @param node cordvtn node
-     */
-    public void deleteNode(CordVtnNode node) {
-        checkNotNull(node);
-        OvsdbClientService ovsdbClient = getOvsdbClient(node);
-        if (ovsdbClient != null && ovsdbClient.isConnected()) {
-            ovsdbClient.disconnect();
+    @Override
+    public void updateNode(CordVtnNode node) {
+        checkNotNull(node, ERR_NULL_NODE);
+        nodeStore.updateNode(node);
+        log.debug(format(MSG_NODE, node.hostname(), MSG_UPDATED));
+    }
+
+    @Override
+    public CordVtnNode removeNode(String hostname) {
+        checkArgument(!Strings.isNullOrEmpty(hostname), ERR_NULL_HOSTNAME);
+        CordVtnNode removed = nodeStore.removeNode(hostname);
+        if (removed == null) {
+            log.warn(format(MSG_NODE, hostname, ERR_NOT_FOUND));
+            return null;
         }
-        nodeStore.remove(node.hostname());
+        log.info(format(MSG_NODE, hostname, MSG_REMOVED));
+        return removed;
     }
 
-    /**
-     * Returns node initialization state.
-     *
-     * @param node cordvtn node
-     * @return true if initial node setup is completed, otherwise false
-     */
-    public boolean isNodeInitComplete(CordVtnNode node) {
-        checkNotNull(node);
-        return isNodeStateComplete(node);
+    @Override
+    public Set<CordVtnNode> nodes() {
+        return nodeStore.nodes();
     }
 
-    /**
-     * Returns the number of the nodes known to the service.
-     *
-     * @return number of nodes
-     */
-    public int getNodeCount() {
-        return nodeStore.size();
-    }
-
-    /**
-     * Returns all nodes known to the service.
-     *
-     * @return list of nodes
-     */
-    public List<CordVtnNode> getNodes() {
-        return nodeStore.values().stream().map(Versioned::value).collect(Collectors.toList());
-    }
-
-    /**
-     * Returns all nodes in complete state.
-     *
-     * @return set of nodes
-     */
+    @Override
     public Set<CordVtnNode> completeNodes() {
-        return getNodes().stream().filter(this::isNodeStateComplete)
-                .collect(Collectors.toSet());
-    }
-
-    /**
-     * Returns physical data plane port number of a given device.
-     *
-     * @param deviceId integration bridge device id
-     * @return port number; null otherwise
-     */
-    public PortNumber dataPort(DeviceId deviceId) {
-        CordVtnNode node = nodeByBridgeId(deviceId);
-        if (node == null) {
-            log.debug("Failed to get node for {}", deviceId);
-            return null;
-        }
-
-        Optional<PortNumber> port = getPortNumber(deviceId, node.dataIface());
-        return port.isPresent() ? port.get() : null;
-    }
-
-    /**
-     * Returns physical data plane IP address of a given device.
-     *
-     * @param deviceId integration bridge device id
-     * @return ip address; null otherwise
-     */
-    public IpAddress dataIp(DeviceId deviceId) {
-        CordVtnNode node = nodeByBridgeId(deviceId);
-        if (node == null) {
-            log.debug("Failed to get node for {}", deviceId);
-            return null;
-        }
-        return node.dataIp().ip();
-    }
-
-    /**
-     * Returns tunnel port number of a given device.
-     *
-     * @param deviceId integration bridge device id
-     * @return port number
-     */
-    public PortNumber tunnelPort(DeviceId deviceId) {
-        Optional<PortNumber> port = getPortNumber(deviceId, DEFAULT_TUNNEL);
-        return port.isPresent() ? port.get() : null;
-    }
-
-    /**
-     * Returns host management interface port number if exists.
-     *
-     * @param deviceId integration bridge device id
-     * @return port number; null if it does not exist
-     */
-    public PortNumber hostManagementPort(DeviceId deviceId) {
-        CordVtnNode node = nodeByBridgeId(deviceId);
-        if (node == null) {
-            log.debug("Failed to get node for {}", deviceId);
-            return null;
-        }
-
-        if (node.hostMgmtIface().isPresent()) {
-            Optional<PortNumber> port = getPortNumber(deviceId, node.hostMgmtIface().get());
-            return port.isPresent() ? port.get() : null;
-        } else {
-            return null;
-        }
-    }
-
-    private Optional<PortNumber> getPortNumber(DeviceId deviceId, String portName) {
-        PortNumber port = deviceService.getPorts(deviceId).stream()
-                .filter(p -> p.annotations().value(PORT_NAME).equals(portName) &&
-                        p.isEnabled())
-                .map(Port::number)
-                .findAny()
-                .orElse(null);
-        return Optional.ofNullable(port);
-    }
-
-    /**
-     * Returns if current node state saved in nodeStore is COMPLETE or not.
-     *
-     * @param node cordvtn node
-     * @return true if it's complete state, otherwise false
-     */
-    private boolean isNodeStateComplete(CordVtnNode node) {
-        checkNotNull(node);
-
         // the state saved in nodeStore can be wrong if IP address settings are changed
         // after the node init has been completed since there's no way to detect it
-        // getNodeState and checkNodeInitState always return correct answer but can be slow
-        Versioned<CordVtnNode> versionedNode = nodeStore.get(node.hostname());
-        CordVtnNodeState state = versionedNode.value().state();
-        return state != null && state.equals(NodeState.COMPLETE);
+        Set<CordVtnNode> nodes = nodes().stream()
+                .filter(node -> node.state() == COMPLETE)
+                .collect(Collectors.toSet());
+        return ImmutableSet.copyOf(nodes);
     }
 
-    /**
-     * Initiates node to serve virtual tenant network.
-     *
-     * @param node cordvtn node
-     */
-    private void initNode(CordVtnNode node) {
-        checkNotNull(node);
-
-        NodeState state = (NodeState) node.state();
-        log.debug("Processing node: {} state: {}", node.hostname(), state);
-
-        state.process(this, node);
+    @Override
+    public CordVtnNode node(String hostname) {
+        checkArgument(!Strings.isNullOrEmpty(hostname), ERR_NULL_HOSTNAME);
+        return nodeStore.node(hostname);
     }
 
-    /**
-     * Performs tasks after node initialization.
-     * It disconnects unnecessary OVSDB connection and installs initial flow
-     * rules on the device.
-     *
-     * @param node cordvtn node
-     */
-    private void postInit(CordVtnNode node) {
-        checkNotNull(node);
-
-        // disconnect OVSDB session once the node bootstrap is done
-        OvsdbClientService ovsdbClient = getOvsdbClient(node);
-        if (ovsdbClient != null && ovsdbClient.isConnected()) {
-            ovsdbClient.disconnect();
-        }
-
-        pipeline.initPipeline(node);
-
-        // adds existing instances to the host list
-        deviceService.getPorts(node.integrationBridgeId()).stream()
-                .filter(port -> !node.systemIfaces().contains(portName(port)) &&
-                        !port.number().equals(PortNumber.LOCAL) &&
-                        port.isEnabled())
-                .forEach(port -> instanceService.addInstance(connectPoint(port)));
-
-        // removes stale instances from the host list
-        hostService.getHosts().forEach(host -> {
-            if (deviceService.getPort(
-                    host.location().deviceId(),
-                    host.location().port()) == null) {
-                instanceService.removeInstance(host.location());
-            }
-        });
-
-        log.info("Finished init {}", node.hostname());
-    }
-
-    /**
-     * Sets a new state for a given cordvtn node.
-     *
-     * @param node cordvtn node
-     * @param newState new node state
-     */
-    private void setNodeState(CordVtnNode node, NodeState newState) {
-        checkNotNull(node);
-        log.debug("Changed {} state: {}", node.hostname(), newState);
-        nodeStore.put(node.hostname(), CordVtnNode.getUpdatedNode(node, newState));
-    }
-
-    /**
-     * Checks current state of a given cordvtn node and returns it.
-     *
-     * @param node cordvtn node
-     * @return node state
-     */
-    private NodeState getNodeState(CordVtnNode node) {
-        checkNotNull(node);
-        if (!isIntegrationBridgeCreated(node)) {
-            return NodeState.INIT;
-        }
-        for (String iface : node.systemIfaces()) {
-            if (!isIfaceCreated(node, iface)) {
-                return NodeState.BRIDGE_CREATED;
-            }
-        }
-        if (!isIpAddressSet(node)) {
-            return NodeState.PORTS_ADDED;
-        }
-        return NodeState.COMPLETE;
-    }
-
-    /**
-     * Returns connection state of OVSDB server for a given node.
-     *
-     * @param node cordvtn node
-     * @return true if it is connected, false otherwise
-     */
-    private boolean isOvsdbConnected(CordVtnNode node) {
-        checkNotNull(node);
-        OvsdbClientService ovsdbClient = getOvsdbClient(node);
-        return deviceService.isAvailable(node.ovsdbId()) &&
-                ovsdbClient != null &&
-                ovsdbClient.isConnected();
-    }
-
-    /**
-     * Connects to OVSDB server for a given node.
-     *
-     * @param node cordvtn node
-     */
-    private void connectOvsdb(CordVtnNode node) {
-        checkNotNull(node);
-        ovsdbController.connect(node.hostMgmtIp().ip(), node.ovsdbPort());
-    }
-
-    /**
-     * Returns OVSDB client for a given node.
-     *
-     * @param node cordvtn node
-     * @return ovsdb client, or null if there's no ovsdb connection
-     */
-    private OvsdbClientService getOvsdbClient(CordVtnNode node) {
-        checkNotNull(node);
-        OvsdbNodeId ovsdb = new OvsdbNodeId(
-                node.hostMgmtIp().ip(), node.ovsdbPort().toInt());
-        return ovsdbController.getOvsdbClient(ovsdb);
-    }
-
-    private void createIntegrationBridge(CordVtnNode node) {
-        Device device = deviceService.getDevice(node.ovsdbId());
-        if (device == null || !device.is(BridgeConfig.class)) {
-            log.error("Failed to create integration bridge on {}", node.ovsdbId());
-            return;
-        }
-
-        String dpid = node.integrationBridgeId().toString().substring(DPID_BEGIN);
-        BridgeDescription bridgeDesc = DefaultBridgeDescription.builder()
-                .name(INTEGRATION_BRIDGE)
-                .failMode(BridgeDescription.FailMode.SECURE)
-                .datapathId(dpid)
-                .disableInBand()
-                .controllers(controllers)
-                .build();
-
-        BridgeConfig bridgeConfig =  device.as(BridgeConfig.class);
-        bridgeConfig.addBridge(bridgeDesc);
-    }
-
-    private void createTunnelInterface(CordVtnNode node) {
-        Device device = deviceService.getDevice(node.ovsdbId());
-        if (device == null || !device.is(InterfaceConfig.class)) {
-            log.error("Failed to create tunnel interface on {}", node.ovsdbId());
-            return;
-        }
-
-        TunnelDescription tunnelDesc = DefaultTunnelDescription.builder()
-                .deviceId(INTEGRATION_BRIDGE)
-                .ifaceName(DEFAULT_TUNNEL)
-                .type(VXLAN)
-                .remote(TunnelEndPoints.flowTunnelEndpoint())
-                .key(TunnelKeys.flowTunnelKey())
-                .build();
-
-        InterfaceConfig ifaceConfig = device.as(InterfaceConfig.class);
-        ifaceConfig.addTunnelMode(DEFAULT_TUNNEL, tunnelDesc);
-    }
-
-    private void addSystemInterface(CordVtnNode node, String ifaceName) {
-        Session session = connect(node.sshInfo());
-        if (session == null || !isInterfaceUp(session, ifaceName)) {
-            log.warn("Interface {} is not available on {}", ifaceName, node.hostname());
-            disconnect(session);
-            return;
-        } else {
-            disconnect(session);
-        }
-
-        Device device = deviceService.getDevice(node.ovsdbId());
-        if (!device.is(BridgeConfig.class)) {
-            log.error("BridgeConfig is not supported for {}", node.ovsdbId());
-            return;
-        }
-
-        BridgeConfig bridgeConfig = device.as(BridgeConfig.class);
-        bridgeConfig.addPort(BridgeName.bridgeName(INTEGRATION_BRIDGE), ifaceName);
-    }
-
-    /**
-     * Flushes IP address from data plane interface and adds data plane IP address
-     * to integration bridge.
-     *
-     * @param node cordvtn node
-     */
-    private void setIpAddress(CordVtnNode node) {
-        Session session = connect(node.sshInfo());
-        if (session == null) {
-            log.debug("Failed to SSH to {}", node.hostname());
-            return;
-        }
-        getCurrentIps(session, INTEGRATION_BRIDGE).stream()
-                .filter(ip -> !ip.equals(node.localMgmtIp().ip()))
-                .filter(ip -> !ip.equals(node.dataIp().ip()))
-                .forEach(ip -> deleteIp(session, ip, INTEGRATION_BRIDGE));
-
-        boolean result = flushIp(session, node.dataIface()) &&
-                setInterfaceUp(session, node.dataIface()) &&
-                addIp(session, node.dataIp(), INTEGRATION_BRIDGE) &&
-                addIp(session, node.localMgmtIp(), INTEGRATION_BRIDGE) &&
-                setInterfaceUp(session, INTEGRATION_BRIDGE);
-
-        disconnect(session);
-        if (result) {
-            setNodeState(node, NodeState.COMPLETE);
-        }
-    }
-
-    private boolean isIntegrationBridgeCreated(CordVtnNode node) {
-        return deviceService.getDevice(node.integrationBridgeId()) != null &&
-                deviceService.isAvailable(node.integrationBridgeId());
-    }
-
-    private boolean isIfaceCreated(CordVtnNode node, String ifaceName) {
-        if (Strings.isNullOrEmpty(ifaceName)) {
-            return false;
-        }
-        return deviceService.getPorts(node.integrationBridgeId()).stream()
-                .anyMatch(p -> portName(p).contains(ifaceName) && p.isEnabled());
-    }
-
-    /**
-     * Checks if the IP addresses are correctly set.
-     *
-     * @param node cordvtn node
-     * @return true if the IP is set, false otherwise
-     */
-    private boolean isIpAddressSet(CordVtnNode node) {
-        Session session = connect(node.sshInfo());
-        if (session == null) {
-            log.debug("Failed to SSH to {}", node.hostname());
-            return false;
-        }
-
-        Set<IpAddress> intBrIps = getCurrentIps(session, INTEGRATION_BRIDGE);
-        boolean result = getCurrentIps(session, node.dataIface()).isEmpty() &&
-                isInterfaceUp(session, node.dataIface()) &&
-                intBrIps.contains(node.dataIp().ip()) &&
-                intBrIps.contains(node.localMgmtIp().ip()) &&
-                isInterfaceUp(session, INTEGRATION_BRIDGE);
-
-        disconnect(session);
-        return result;
-    }
-
-    /**
-     * Returns connect point of a given port.
-     *
-     * @param port port
-     * @return connect point
-     */
-    private ConnectPoint connectPoint(Port port) {
-        return new ConnectPoint(port.element().id(), port.number());
-    }
-
-    /**
-     * Returns cordvtn node associated with a given OVSDB device.
-     *
-     * @param ovsdbId OVSDB device id
-     * @return cordvtn node, null if it fails to find the node
-     */
-    private CordVtnNode nodeByOvsdbId(DeviceId ovsdbId) {
-        return getNodes().stream()
-                .filter(node -> node.ovsdbId().equals(ovsdbId))
-                .findFirst().orElse(null);
-    }
-
-    /**
-     * Returns cordvtn node associated with a given integration bridge.
-     *
-     * @param bridgeId device id of integration bridge
-     * @return cordvtn node, null if it fails to find the node
-     */
-    private CordVtnNode nodeByBridgeId(DeviceId bridgeId) {
-        return getNodes().stream()
-                .filter(node -> node.integrationBridgeId().equals(bridgeId))
-                .findFirst().orElse(null);
-    }
-
-    /**
-     * Returns port name.
-     *
-     * @param port port
-     * @return port name
-     */
-    private String portName(Port port) {
-        return port.annotations().value(PORT_NAME);
-    }
-
-    private class OvsdbHandler implements ConnectionHandler<Device> {
-
-        @Override
-        public void connected(Device device) {
-            CordVtnNode node = nodeByOvsdbId(device.id());
-            if (node != null) {
-                setNodeState(node, getNodeState(node));
-            } else {
-                log.info("{} is detected on unregistered node, ignore it.", device.id());
-            }
-        }
-
-        @Override
-        public void disconnected(Device device) {
-            log.debug("Device {} is disconnected", device.id());
-            adminService.removeDevice(device.id());
-        }
-    }
-
-    private class BridgeHandler implements ConnectionHandler<Device> {
-
-        @Override
-        public void connected(Device device) {
-            CordVtnNode node = nodeByBridgeId(device.id());
-            if (node != null) {
-                setNodeState(node, getNodeState(node));
-            } else {
-                log.info("{} is detected on unregistered node, ignore it.", device.id());
-            }
-        }
-
-        @Override
-        public void disconnected(Device device) {
-            CordVtnNode node = nodeByBridgeId(device.id());
-            if (node != null) {
-                log.warn("Integration Bridge is disconnected from {}", node.hostname());
-                setNodeState(node, NodeState.INCOMPLETE);
-            }
-        }
-
-        /**
-         * Handles port added situation.
-         * If the added port is tunnel or data plane interface, proceed to the remaining
-         * node initialization. Otherwise, do nothing.
-         *
-         * @param port port
-         */
-        public void portAdded(Port port) {
-            CordVtnNode node = nodeByBridgeId((DeviceId) port.element().id());
-            String portName = portName(port);
-            if (node == null) {
-                log.info("{} is added to unregistered node, ignore it.", portName);
-                return;
-            }
-
-            if (node.systemIfaces().contains(portName)) {
-                setNodeState(node, getNodeState(node));
-            } else if (isNodeStateComplete(node)) {
-                // TODO move this logic to InstanceManager
-                instanceService.addInstance(connectPoint(port));
-            } else {
-                log.warn("Instance is detected on incomplete node, ignore it.", portName);
-            }
-        }
-
-        /**
-         * Handles port removed situation.
-         * If the removed port is tunnel or data plane interface, proceed to the remaining
-         * node initialization.Others, do nothing.
-         *
-         * @param port port
-         */
-        public void portRemoved(Port port) {
-            CordVtnNode node = nodeByBridgeId((DeviceId) port.element().id());
-            String portName = portName(port);
-            if (node == null) {
-                log.info("{} is removed from unregistered node, ignore it.", portName);
-                return;
-            }
-
-            if (node.systemIfaces().contains(portName)) {
-                setNodeState(node, NodeState.INCOMPLETE);
-            } else if (isNodeStateComplete(node)) {
-                // TODO move this logic to InstanceManager
-                instanceService.removeInstance(connectPoint(port));
-            } else {
-                log.warn("VM is vanished from incomplete node, ignore it.", portName);
-            }
-        }
-    }
-
-    private class InternalDeviceListener implements DeviceListener {
-
-        @Override
-        public boolean isRelevant(DeviceEvent event) {
-            NodeId leaderNodeId = leadershipService.getLeader(appId.name());
-            return Objects.equals(localNodeId, leaderNodeId);
-        }
-
-        @Override
-        public void event(DeviceEvent event) {
-
-            Device device = event.subject();
-            ConnectionHandler<Device> handler = device.type().equals(SWITCH) ?
-                    bridgeHandler : ovsdbHandler;
-
-            switch (event.type()) {
-                case PORT_ADDED:
-                    eventExecutor.execute(() -> {
-                        log.info("Port {} is added to {}",
-                                 event.port().annotations().value(PORT_NAME),
-                                 event.subject().id());
-                        bridgeHandler.portAdded(event.port());
-                    });
-                    break;
-                case PORT_UPDATED:
-                    if (event.port().isEnabled()) {
-                        eventExecutor.execute(() -> {
-                            log.info("Port {} is added to {}",
-                                    event.port().annotations().value(PORT_NAME),
-                                    event.subject().id());
-                            bridgeHandler.portAdded(event.port());
-                        });
-                    } else {
-                        eventExecutor.execute(() -> {
-                            log.info("Port {} is removed from {}",
-                                    event.port().annotations().value(PORT_NAME),
-                                    event.subject().id());
-                            bridgeHandler.portRemoved(event.port());
-                        });
-                    }
-                    break;
-                case PORT_REMOVED:
-                    eventExecutor.execute(() -> {
-                        log.info("Port {} is removed from {}",
-                                event.port().annotations().value(PORT_NAME),
-                                event.subject().id());
-                        bridgeHandler.portRemoved(event.port());
-                    });
-                break;
-                case DEVICE_ADDED:
-                case DEVICE_AVAILABILITY_CHANGED:
-                    if (deviceService.isAvailable(device.id())) {
-                        eventExecutor.execute(() -> {
-                            log.info("Device {} is connected",
-                                     event.subject().id());
-                            handler.connected(device);
-                        });
-                    } else {
-                        eventExecutor.execute(() -> {
-                            log.info("Device {} is disconnected",
-                                     event.subject().id());
-                            handler.disconnected(device);
-                        });
-                    }
-                    break;
-                default:
-                    break;
-            }
-        }
+    @Override
+    public CordVtnNode node(DeviceId deviceId) {
+        checkNotNull(deviceId, ERR_NULL_DEVICE_ID);
+        return nodes().stream()
+                .filter(node -> node.integrationBridgeId().equals(deviceId) ||
+                        node.ovsdbId().equals(deviceId))
+                .findAny().orElse(null);
     }
 
     /**
@@ -860,21 +193,18 @@
 
         CordVtnConfig config = configService.getConfig(appId, CordVtnConfig.class);
         if (config == null) {
-            log.debug("No configuration found");
+            log.warn("No configuration found");
             return;
         }
-        config.cordVtnNodes().forEach(this::addOrUpdateNode);
-    }
-
-    private void readControllers() {
-        CordVtnConfig config = configService.getConfig(appId, CordVtnConfig.class);
-        if (config == null) {
-            log.debug("No configuration found");
-            return;
-        }
-        controllers = config.controllers();
-        controllers.forEach(ctrl -> {
-            log.debug("Added controller {}:{}", ctrl.ip(), ctrl.port());
+        config.cordVtnNodes().forEach(node -> {
+            log.info("Read node from network config: {}", node.hostname());
+            CordVtnNode existing = node(node.hostname());
+            if (existing == null) {
+                createNode(node);
+            } else if (!existing.equals(node)) {
+                // FIXME maybe we need to re-check node states
+                updateNode(node);
+            }
         });
     }
 
@@ -889,10 +219,7 @@
             switch (event.type()) {
                 case CONFIG_ADDED:
                 case CONFIG_UPDATED:
-                    eventExecutor.execute(() -> {
-                        readControllers();
-                        readNodes();
-                    });
+                    eventExecutor.execute(CordVtnNodeManager.this::readNodes);
                     break;
                 default:
                     break;
@@ -900,44 +227,12 @@
         }
     }
 
-    private class InternalMapListener implements MapEventListener<String, CordVtnNode> {
+    private class InternalCordVtnNodeStoreDelegate implements CordVtnNodeStoreDelegate {
 
         @Override
-        public void event(MapEvent<String, CordVtnNode> event) {
-            NodeId leaderNodeId = leadershipService.getLeader(appId.name());
-            if (!Objects.equals(localNodeId, leaderNodeId)) {
-                // do not allow to proceed without leadership
-                return;
-            }
-
-            CordVtnNode oldNode;
-            CordVtnNode newNode;
-
-            switch (event.type()) {
-            case UPDATE:
-                oldNode = event.oldValue().value();
-                newNode = event.newValue().value();
-
-                log.info("Reloaded {}", newNode.hostname());
-                if (!newNode.equals(oldNode)) {
-                    log.debug("New node: {}", newNode);
-                }
-                // performs init procedure even if the node is not changed
-                // for robustness since it's no harm to run init procedure
-                // multiple times
-                initNode(newNode);
-                break;
-            case INSERT:
-                newNode = event.newValue().value();
-                log.info("Added {}", newNode.hostname());
-                initNode(newNode);
-                break;
-            case REMOVE:
-                oldNode = event.oldValue().value();
-                log.info("Removed {}", oldNode.hostname());
-                break;
-            default:
-                break;
+        public void notify(CordVtnNodeEvent event) {
+            if (event != null) {
+                process(event);
             }
         }
     }
diff --git a/src/main/java/org/opencord/cordvtn/impl/DefaultCordVtnNode.java b/src/main/java/org/opencord/cordvtn/impl/DefaultCordVtnNode.java
new file mode 100644
index 0000000..e11e2d3
--- /dev/null
+++ b/src/main/java/org/opencord/cordvtn/impl/DefaultCordVtnNode.java
@@ -0,0 +1,322 @@
+/*
+ * Copyright 2017-present 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.opencord.cordvtn.impl;
+
+import com.google.common.base.MoreObjects;
+import com.google.common.base.Strings;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Sets;
+import org.onlab.packet.TpPort;
+import org.onosproject.net.DeviceId;
+import org.opencord.cordvtn.api.net.CidrAddr;
+import org.opencord.cordvtn.api.node.CordVtnNode;
+import org.opencord.cordvtn.api.node.CordVtnNodeState;
+import org.opencord.cordvtn.api.node.SshAccessInfo;
+
+import java.util.Objects;
+import java.util.Set;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
+import static org.opencord.cordvtn.api.Constants.DEFAULT_OVSDB_PORT;
+import static org.opencord.cordvtn.api.Constants.DEFAULT_TUNNEL;
+
+/**
+ * Representation of a compute infrastructure node for CORD VTN service.
+ */
+public final class DefaultCordVtnNode implements CordVtnNode {
+
+    private final String hostname;
+    private final CidrAddr hostMgmtIp;
+    private final CidrAddr localMgmtIp;
+    private final CidrAddr dataIp;
+    private final DeviceId integrationBridgeId;
+    private final String dataIface;
+    private final String hostMgmtIface;
+    private final TpPort ovsdbPort;
+    private final SshAccessInfo sshInfo;
+    private final CordVtnNodeState state;
+
+    private DefaultCordVtnNode(String hostname,
+                               CidrAddr hostMgmtIp,
+                               CidrAddr localMgmtIp,
+                               CidrAddr dataIp,
+                               DeviceId integrationBridgeId,
+                               String dataIface,
+                               String hostMgmtIface,
+                               TpPort ovsdbPort,
+                               SshAccessInfo sshInfo,
+                               CordVtnNodeState state) {
+        this.hostname = hostname;
+        this.hostMgmtIp = hostMgmtIp;
+        this.localMgmtIp = localMgmtIp;
+        this.dataIp = dataIp;
+        this.integrationBridgeId = integrationBridgeId;
+        this.dataIface = dataIface;
+        this.hostMgmtIface = hostMgmtIface;
+        this.ovsdbPort = ovsdbPort;
+        this.sshInfo = sshInfo;
+        this.state = state;
+    }
+
+    /**
+     * Returns cordvtn node with the new state.
+     *
+     * @param node cordvtn node
+     * @param state cordvtn node state
+     * @return cordvtn node
+     */
+    public static CordVtnNode updatedState(CordVtnNode node, CordVtnNodeState state) {
+        return new DefaultCordVtnNode(node.hostname(),
+                node.hostManagementIp(),
+                node.localManagementIp(),
+                node.dataIp(),
+                node.integrationBridgeId(),
+                node.dataInterface(),
+                node.hostManagementInterface(),
+                node.ovsdbPort(),
+                node.sshInfo(),
+                state);
+    }
+
+    @Override
+    public String hostname() {
+        return this.hostname;
+    }
+
+    @Override
+    public CidrAddr hostManagementIp() {
+        return this.hostMgmtIp;
+    }
+
+    @Override
+    public CidrAddr localManagementIp() {
+        return this.localMgmtIp;
+    }
+
+    @Override
+    public CidrAddr dataIp() {
+        return this.dataIp;
+    }
+
+    @Override
+    public DeviceId integrationBridgeId() {
+        return this.integrationBridgeId;
+    }
+
+    @Override
+    public String dataInterface() {
+        return this.dataIface;
+    }
+
+    @Override
+    public String hostManagementInterface() {
+        return this.hostMgmtIface;
+    }
+
+    @Override
+    public TpPort ovsdbPort() {
+        return this.ovsdbPort;
+    }
+
+    @Override
+    public SshAccessInfo sshInfo() {
+        return this.sshInfo;
+    }
+
+    @Override
+    public CordVtnNodeState state() {
+        return this.state;
+    }
+
+    @Override
+    public DeviceId ovsdbId() {
+        return DeviceId.deviceId("ovsdb:" + this.hostMgmtIp.ip().toString());
+    }
+
+    @Override
+    public Set<String> systemInterfaces() {
+        Set<String> ifaces = Sets.newHashSet(DEFAULT_TUNNEL, dataIface);
+        if (hostMgmtIface != null) {
+            ifaces.add(hostMgmtIface);
+        }
+        return ImmutableSet.copyOf(ifaces);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+
+        if (obj instanceof DefaultCordVtnNode) {
+            DefaultCordVtnNode that = (DefaultCordVtnNode) obj;
+            if (Objects.equals(hostname, that.hostname) &&
+                    Objects.equals(hostMgmtIp, that.hostMgmtIp) &&
+                    Objects.equals(localMgmtIp, that.localMgmtIp) &&
+                    Objects.equals(dataIp, that.dataIp) &&
+                    Objects.equals(integrationBridgeId, that.integrationBridgeId) &&
+                    Objects.equals(dataIface, that.dataIface) &&
+                    Objects.equals(hostMgmtIface, that.hostMgmtIface) &&
+                    Objects.equals(ovsdbPort, that.ovsdbPort) &&
+                    Objects.equals(sshInfo, that.sshInfo)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(hostname,
+                hostMgmtIp,
+                localMgmtIp,
+                dataIp,
+                integrationBridgeId,
+                dataIface,
+                hostMgmtIface,
+                ovsdbPort,
+                sshInfo);
+    }
+
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(getClass())
+                .add("hostname", hostname)
+                .add("hostMgmtIp", hostMgmtIp)
+                .add("localMgmtIp", localMgmtIp)
+                .add("dataIp", dataIp)
+                .add("integrationBridgeId", integrationBridgeId)
+                .add("dataIface", dataIface)
+                .add("hostMgmtIface", hostMgmtIface)
+                .add("ovsdbPort", ovsdbPort)
+                .add("sshInfo", sshInfo)
+                .add("state", state)
+                .toString();
+    }
+
+    /**
+     * Returns new node builder instance.
+     *
+     * @return cordvtn node builder
+     */
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    public static final class Builder implements CordVtnNode.Builder {
+
+        private String hostname;
+        private CidrAddr hostMgmtIp;
+        private CidrAddr localMgmtIp;
+        private CidrAddr dataIp;
+        private DeviceId integrationBridgeId;
+        private String dataIface;
+        private String hostMgmtIface;
+        private TpPort ovsdbPort = TpPort.tpPort(DEFAULT_OVSDB_PORT);
+        private SshAccessInfo sshInfo;
+        private CordVtnNodeState state = CordVtnNodeState.INIT;
+
+        private Builder() {
+        }
+
+        @Override
+        public CordVtnNode build() {
+            checkArgument(!Strings.isNullOrEmpty(hostname), "Hostname cannot be null");
+            checkNotNull(hostMgmtIp, "Host management IP address cannot be null");
+            checkNotNull(localMgmtIp, "Local management IP address cannot be null");
+            checkNotNull(dataIp, "Data IP address cannot be null");
+            checkNotNull(integrationBridgeId, "Integration bridge ID cannot be null");
+            checkArgument(!Strings.isNullOrEmpty(dataIface), "Data interface cannot be null");
+            if (hostMgmtIface != null) {
+                checkArgument(!Strings.isNullOrEmpty(hostMgmtIface),
+                        "Host management interface cannot be empty string");
+            }
+            checkNotNull(sshInfo, "SSH access information cannot be null");
+            checkNotNull(state, "Node state cannot be null");
+
+            return new DefaultCordVtnNode(hostname,
+                    hostMgmtIp,
+                    localMgmtIp,
+                    dataIp,
+                    integrationBridgeId,
+                    dataIface,
+                    hostMgmtIface,
+                    ovsdbPort,
+                    sshInfo, state);
+        }
+
+        @Override
+        public Builder hostname(String hostname) {
+            this.hostname = hostname;
+            return this;
+        }
+
+        @Override
+        public Builder hostManagementIp(CidrAddr hostMgmtIp) {
+            this.hostMgmtIp = hostMgmtIp;
+            return this;
+        }
+
+        @Override
+        public Builder localManagementIp(CidrAddr localMgmtIp) {
+            this.localMgmtIp = localMgmtIp;
+            return this;
+        }
+
+        @Override
+        public Builder dataIp(CidrAddr dataIp) {
+            this.dataIp = dataIp;
+            return this;
+        }
+
+        @Override
+        public Builder integrationBridgeId(DeviceId deviceId) {
+            this.integrationBridgeId = deviceId;
+            return this;
+        }
+
+        @Override
+        public Builder dataInterface(String dataIface) {
+            this.dataIface = dataIface;
+            return this;
+        }
+
+        @Override
+        public Builder hostManagementInterface(String hostMgmtIface) {
+            this.hostMgmtIface = hostMgmtIface;
+            return this;
+        }
+
+        @Override
+        public Builder ovsdbPort(TpPort port) {
+            this.ovsdbPort = port;
+            return this;
+        }
+
+        @Override
+        public Builder sshInfo(SshAccessInfo sshInfo) {
+            this.sshInfo = sshInfo;
+            return this;
+        }
+
+        @Override
+        public Builder state(CordVtnNodeState state) {
+            this.state = state;
+            return this;
+        }
+    }
+}
diff --git a/src/main/java/org/opencord/cordvtn/impl/DefaultCordVtnNodeHandler.java b/src/main/java/org/opencord/cordvtn/impl/DefaultCordVtnNodeHandler.java
new file mode 100644
index 0000000..a663e38
--- /dev/null
+++ b/src/main/java/org/opencord/cordvtn/impl/DefaultCordVtnNodeHandler.java
@@ -0,0 +1,601 @@
+/*
+ * Copyright 2017-present 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.opencord.cordvtn.impl;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableSet;
+import com.jcraft.jsch.Session;
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Reference;
+import org.apache.felix.scr.annotations.ReferenceCardinality;
+import org.apache.felix.scr.annotations.Service;
+import org.onlab.packet.IpAddress;
+import org.onosproject.cluster.ClusterService;
+import org.onosproject.cluster.LeadershipService;
+import org.onosproject.cluster.NodeId;
+import org.onosproject.core.ApplicationId;
+import org.onosproject.core.CoreService;
+import org.onosproject.net.ConnectPoint;
+import org.onosproject.net.Device;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.Port;
+import org.onosproject.net.PortNumber;
+import org.onosproject.net.behaviour.BridgeConfig;
+import org.onosproject.net.behaviour.BridgeDescription;
+import org.onosproject.net.behaviour.BridgeName;
+import org.onosproject.net.behaviour.ControllerInfo;
+import org.onosproject.net.behaviour.DefaultBridgeDescription;
+import org.onosproject.net.behaviour.DefaultTunnelDescription;
+import org.onosproject.net.behaviour.InterfaceConfig;
+import org.onosproject.net.behaviour.TunnelDescription;
+import org.onosproject.net.behaviour.TunnelEndPoints;
+import org.onosproject.net.behaviour.TunnelKeys;
+import org.onosproject.net.config.NetworkConfigEvent;
+import org.onosproject.net.config.NetworkConfigListener;
+import org.onosproject.net.config.NetworkConfigService;
+import org.onosproject.net.device.DeviceAdminService;
+import org.onosproject.net.device.DeviceEvent;
+import org.onosproject.net.device.DeviceListener;
+import org.onosproject.net.device.DeviceService;
+import org.onosproject.net.host.HostService;
+import org.onosproject.ovsdb.controller.OvsdbClientService;
+import org.onosproject.ovsdb.controller.OvsdbController;
+import org.onosproject.ovsdb.controller.OvsdbNodeId;
+import org.opencord.cordvtn.api.CordVtnConfig;
+import org.opencord.cordvtn.api.core.CordVtnPipeline;
+import org.opencord.cordvtn.api.core.InstanceService;
+import org.opencord.cordvtn.api.node.CordVtnNode;
+import org.opencord.cordvtn.api.node.CordVtnNodeAdminService;
+import org.opencord.cordvtn.api.node.CordVtnNodeEvent;
+import org.opencord.cordvtn.api.node.CordVtnNodeHandler;
+import org.opencord.cordvtn.api.node.CordVtnNodeListener;
+import org.opencord.cordvtn.api.node.CordVtnNodeService;
+import org.opencord.cordvtn.api.node.CordVtnNodeState;
+import org.opencord.cordvtn.api.node.DeviceHandler;
+import org.slf4j.Logger;
+
+import java.util.List;
+import java.util.Objects;
+import java.util.Set;
+import java.util.concurrent.ExecutorService;
+import java.util.stream.Collectors;
+
+import static java.lang.String.format;
+import static java.util.concurrent.Executors.newSingleThreadExecutor;
+import static org.onlab.util.Tools.groupedThreads;
+import static org.onosproject.net.AnnotationKeys.PORT_NAME;
+import static org.onosproject.net.Device.Type.SWITCH;
+import static org.onosproject.net.behaviour.TunnelDescription.Type.VXLAN;
+import static org.opencord.cordvtn.api.Constants.CORDVTN_APP_ID;
+import static org.opencord.cordvtn.api.Constants.DEFAULT_TUNNEL;
+import static org.opencord.cordvtn.api.Constants.INTEGRATION_BRIDGE;
+import static org.opencord.cordvtn.api.node.CordVtnNodeState.*;
+import static org.opencord.cordvtn.impl.DefaultCordVtnNode.updatedState;
+import static org.opencord.cordvtn.impl.RemoteIpCommandUtil.*;
+import static org.opencord.cordvtn.impl.RemoteIpCommandUtil.disconnect;
+import static org.opencord.cordvtn.impl.RemoteIpCommandUtil.isInterfaceUp;
+import static org.slf4j.LoggerFactory.getLogger;
+
+/**
+ * Implementation of the {@link CordVtnNodeHandler} with OVSDB and SSH exec channel.
+ */
+@Component(immediate = true)
+@Service
+public class DefaultCordVtnNodeHandler implements CordVtnNodeHandler {
+
+    protected final Logger log = getLogger(getClass());
+
+    private static final String ERR_INCOMPLETE = "%s is %s from incomplete node, ignore it";
+    private static final String ERR_UNREGISTERED = "%s is %s from unregistered node, ignore it";
+    private static final String ERR_DETECTED = "detected";
+    private static final String ERR_VANISHED = "vanished";
+
+    private static final int DPID_BEGIN = 3;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected CoreService coreService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected LeadershipService leadershipService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected ClusterService clusterService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected NetworkConfigService configService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected DeviceService deviceService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected DeviceAdminService deviceAdminService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected HostService hostService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected OvsdbController ovsdbController;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected CordVtnNodeService nodeService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected CordVtnNodeAdminService nodeAdminService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected InstanceService instanceService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected CordVtnPipeline pipelineService;
+
+    private final ExecutorService eventExecutor = newSingleThreadExecutor(
+            groupedThreads(this.getClass().getSimpleName(), "event-handler", log));
+    private final NetworkConfigListener configListener = new InternalConfigListener();
+    private final DeviceListener deviceListener = new InternalDeviceListener();
+    private final DeviceHandler ovsdbHandler = new OvsdbDeviceHandler();
+    private final DeviceHandler intgBridgeHandler = new IntegrationBridgeDeviceHandler();
+    private final CordVtnNodeListener nodeListener = new InternalCordVtnNodeListener();
+
+    private ApplicationId appId;
+    private NodeId localNodeId;
+    private List<ControllerInfo> controllers = ImmutableList.of();
+
+    @Activate
+    protected void activate() {
+        appId = coreService.registerApplication(CORDVTN_APP_ID);
+        leadershipService.runForLeadership(appId.name());
+        localNodeId = clusterService.getLocalNode().id();
+
+        configService.addListener(configListener);
+        deviceService.addListener(deviceListener);
+        nodeService.addListener(nodeListener);
+
+        readControllers();
+        log.info("Started");
+    }
+
+    @Deactivate
+    protected void deactivate() {
+        nodeService.removeListener(nodeListener);
+        deviceService.removeListener(deviceListener);
+        configService.removeListener(configListener);
+
+        leadershipService.withdraw(appId.name());
+        eventExecutor.shutdown();
+
+        log.info("Stopped");
+    }
+
+    @Override
+    public void processInitState(CordVtnNode node) {
+        if (!isOvsdbConnected(node)) {
+            ovsdbController.connect(node.hostManagementIp().ip(), node.ovsdbPort());
+            return;
+        }
+        createIntegrationBridge(node);
+    }
+
+    @Override
+    public void processDeviceCreatedState(CordVtnNode node) {
+        if (!isOvsdbConnected(node)) {
+            ovsdbController.connect(node.hostManagementIp().ip(), node.ovsdbPort());
+            return;
+        }
+        createTunnelInterface(node);
+        addSystemInterface(node, node.dataInterface());
+        if (node.hostManagementInterface() != null) {
+            addSystemInterface(node, node.hostManagementInterface());
+        }
+    }
+
+    @Override
+    public void processPortCreatedState(CordVtnNode node) {
+        configureInterface(node);
+    }
+
+    @Override
+    public void processCompleteState(CordVtnNode node) {
+        OvsdbClientService ovsdbClient = ovsdbController.getOvsdbClient(
+                new OvsdbNodeId(
+                        node.hostManagementIp().ip(),
+                        node.ovsdbPort().toInt()));
+        if (ovsdbClient != null && ovsdbClient.isConnected()) {
+            ovsdbClient.disconnect();
+        }
+        // TODO fix postInit to be done in the proper services
+        postInit(node);
+        log.info("Finished init {}", node.hostname());
+    }
+
+    private boolean isOvsdbConnected(CordVtnNode node) {
+        OvsdbClientService ovsdbClient = ovsdbController.getOvsdbClient(
+                new OvsdbNodeId(
+                        node.hostManagementIp().ip(),
+                        node.ovsdbPort().toInt()));
+        return deviceService.isAvailable(node.ovsdbId()) && ovsdbClient != null &&
+                ovsdbClient.isConnected();
+    }
+
+    private void createIntegrationBridge(CordVtnNode node) {
+        Device device = deviceService.getDevice(node.ovsdbId());
+        if (device == null || !device.is(BridgeConfig.class)) {
+            log.error("Failed to create integration bridge on {}", node.ovsdbId());
+            return;
+        }
+        String dpid = node.integrationBridgeId().toString().substring(DPID_BEGIN);
+        BridgeDescription bridgeDesc = DefaultBridgeDescription.builder()
+                .name(INTEGRATION_BRIDGE)
+                .failMode(BridgeDescription.FailMode.SECURE)
+                .datapathId(dpid)
+                .disableInBand()
+                .controllers(controllers)
+                .build();
+
+        BridgeConfig bridgeConfig = device.as(BridgeConfig.class);
+        bridgeConfig.addBridge(bridgeDesc);
+    }
+
+    private void createTunnelInterface(CordVtnNode node) {
+        Device device = deviceService.getDevice(node.ovsdbId());
+        if (device == null || !device.is(InterfaceConfig.class)) {
+            log.error("Failed to create tunnel interface on {}", node.ovsdbId());
+            return;
+        }
+        TunnelDescription tunnelDesc = DefaultTunnelDescription.builder()
+                .deviceId(INTEGRATION_BRIDGE)
+                .ifaceName(DEFAULT_TUNNEL)
+                .type(VXLAN)
+                .remote(TunnelEndPoints.flowTunnelEndpoint())
+                .key(TunnelKeys.flowTunnelKey())
+                .build();
+
+        InterfaceConfig ifaceConfig = device.as(InterfaceConfig.class);
+        ifaceConfig.addTunnelMode(DEFAULT_TUNNEL, tunnelDesc);
+    }
+
+    private void addSystemInterface(CordVtnNode node, String ifaceName) {
+        Session session = connect(node.sshInfo());
+        if (session == null || !isInterfaceUp(session, ifaceName)) {
+            log.error("Interface {} is not available on {}", ifaceName, node.hostname());
+            disconnect(session);
+            return;
+        } else {
+            disconnect(session);
+        }
+
+        Device device = deviceService.getDevice(node.ovsdbId());
+        if (!device.is(BridgeConfig.class)) {
+            log.error("BridgeConfig is not supported for {}", node.ovsdbId());
+            return;
+        }
+
+        BridgeConfig bridgeConfig = device.as(BridgeConfig.class);
+        bridgeConfig.addPort(BridgeName.bridgeName(INTEGRATION_BRIDGE), ifaceName);
+    }
+
+    private void configureInterface(CordVtnNode node) {
+        Session session = connect(node.sshInfo());
+        if (session == null) {
+            log.error("Failed to SSH to {}", node.hostname());
+            return;
+        }
+        getCurrentIps(session, INTEGRATION_BRIDGE).stream()
+                .filter(ip -> !ip.equals(node.localManagementIp().ip()))
+                .filter(ip -> !ip.equals(node.dataIp().ip()))
+                .forEach(ip -> deleteIp(session, ip, INTEGRATION_BRIDGE));
+
+        final boolean result = flushIp(session, node.dataInterface()) &&
+                setInterfaceUp(session, node.dataInterface()) &&
+                addIp(session, node.dataIp(), INTEGRATION_BRIDGE) &&
+                addIp(session, node.localManagementIp(), INTEGRATION_BRIDGE) &&
+                setInterfaceUp(session, INTEGRATION_BRIDGE);
+
+        disconnect(session);
+        if (result) {
+            bootstrapNode(node);
+        }
+    }
+
+    private void postInit(CordVtnNode node) {
+        // TODO move the below line to DefaultCordVtnPipeline
+        pipelineService.initPipeline(node);
+
+        // TODO move the logic below to InstanceManager
+        // adds existing instances to the host list
+        deviceService.getPorts(node.integrationBridgeId()).stream()
+                .filter(port -> port.isEnabled() &&
+                        !port.number().equals(PortNumber.LOCAL) &&
+                        !node.systemInterfaces().contains(port.annotations().value(PORT_NAME)))
+                .forEach(port -> instanceService.addInstance(new ConnectPoint(
+                        port.element().id(),
+                        port.number()
+                )));
+        // removes stale instances from the host list
+        hostService.getHosts().forEach(host -> {
+            if (deviceService.getPort(
+                    host.location().deviceId(),
+                    host.location().port()) == null) {
+                instanceService.removeInstance(host.location());
+            }
+        });
+    }
+
+    private class OvsdbDeviceHandler implements DeviceHandler {
+
+        @Override
+        public void connected(Device device) {
+            CordVtnNode node = nodeService.node(device.id());
+            if (node != null) {
+                bootstrapNode(node);
+            }
+        }
+
+        @Override
+        public void disconnected(Device device) {
+            CordVtnNode node = nodeService.node(device.id());
+            if (node != null && node.state() == COMPLETE) {
+                log.debug("Device({}) from {} disconnected", device.id(), node.hostname());
+                deviceAdminService.removeDevice(device.id());
+            }
+        }
+    }
+
+    private class IntegrationBridgeDeviceHandler implements DeviceHandler {
+
+        @Override
+        public void connected(Device device) {
+            CordVtnNode node = nodeService.node(device.id());
+            if (node != null) {
+                bootstrapNode(node);
+            }
+        }
+
+        @Override
+        public void disconnected(Device device) {
+            CordVtnNode node = nodeService.node(device.id());
+            if (node != null) {
+                log.warn("Device({}) from {} disconnected", device.id(), node.hostname());
+                setState(node, INIT);
+            }
+        }
+
+        @Override
+        public void portAdded(Port port) {
+            CordVtnNode node = nodeService.node((DeviceId) port.element().id());
+            String portName = port.annotations().value(PORT_NAME);
+            if (node == null) {
+                log.warn(format(ERR_UNREGISTERED, portName, ERR_DETECTED));
+                return;
+            }
+            if (node.systemInterfaces().contains(portName)) {
+                if (node.state() == DEVICE_CREATED) {
+                    bootstrapNode(node);
+                }
+            } else if (node.state() == COMPLETE) {
+                // TODO move this logic to InstanceManager
+                instanceService.addInstance(new ConnectPoint(port.element().id(),
+                        port.number()));
+            } else {
+                log.warn(format(ERR_INCOMPLETE, portName, ERR_DETECTED));
+            }
+        }
+
+        @Override
+        public void portRemoved(Port port) {
+            CordVtnNode node = nodeService.node((DeviceId) port.element().id());
+            String portName = port.annotations().value(PORT_NAME);
+            if (node == null) {
+                log.warn(format(ERR_UNREGISTERED, portName, ERR_VANISHED));
+                return;
+            }
+            if (node.systemInterfaces().contains(portName)) {
+                if (node.state() == PORT_CREATED || node.state() == COMPLETE) {
+                    // always falls back to INIT state to avoid a mess caused by
+                    // the multiple events received out of order
+                    setState(node, INIT);
+                }
+            } else if (node.state() == COMPLETE) {
+                // TODO move this logic to InstanceManager
+                instanceService.removeInstance(new ConnectPoint(port.element().id(),
+                        port.number()));
+            } else {
+                log.warn(format(ERR_INCOMPLETE, portName, ERR_VANISHED));
+            }
+        }
+    }
+
+    private class InternalDeviceListener implements DeviceListener {
+
+        @Override
+        public void event(DeviceEvent event) {
+            eventExecutor.execute(() -> {
+                NodeId leader = leadershipService.getLeader(appId.name());
+                if (!Objects.equals(localNodeId, leader)) {
+                    // do not allow to proceed without leadership
+                    return;
+                }
+                handle(event);
+            });
+        }
+
+        private void handle(DeviceEvent event) {
+            DeviceHandler handler = event.subject().type().equals(SWITCH) ?
+                    intgBridgeHandler : ovsdbHandler;
+            Device device = event.subject();
+
+            switch (event.type()) {
+                case DEVICE_AVAILABILITY_CHANGED:
+                case DEVICE_ADDED:
+                    if (deviceService.isAvailable(device.id())) {
+                        log.debug("Device {} is connected", device.id());
+                        handler.connected(device);
+                    } else {
+                        log.debug("Device {} is disconnected", device.id());
+                        handler.disconnected(device);
+                    }
+                    break;
+                case PORT_ADDED:
+                    log.debug("Port {} is added to {}",
+                            event.port().annotations().value(PORT_NAME),
+                            device.id());
+                    handler.portAdded(event.port());
+                    break;
+                case PORT_UPDATED:
+                    if (event.port().isEnabled()) {
+                        log.debug("Port {} is added to {}",
+                                event.port().annotations().value(PORT_NAME),
+                                device.id());
+                        handler.portAdded(event.port());
+                    } else {
+                        log.debug("Port {} is removed from {}",
+                                event.port().annotations().value(PORT_NAME),
+                                device.id());
+                        handler.portRemoved(event.port());
+                    }
+                    break;
+                case PORT_REMOVED:
+                    log.debug("Port {} is removed from {}",
+                            event.port().annotations().value(PORT_NAME),
+                            device.id());
+                    handler.portRemoved(event.port());
+                    break;
+                default:
+                    break;
+            }
+        }
+    }
+
+    private Set<String> activePorts(DeviceId deviceId) {
+        Set<String> activePorts = deviceService.getPorts(deviceId).stream()
+                .filter(Port::isEnabled)
+                .map(port -> port.annotations().value(PORT_NAME))
+                .collect(Collectors.toSet());
+        return ImmutableSet.copyOf(activePorts);
+    }
+
+    private boolean isIpAddressSet(CordVtnNode node) {
+        Session session = connect(node.sshInfo());
+        if (session == null) {
+            log.warn("Failed to SSH to {}", node.hostname());
+            return false;
+        }
+        Set<IpAddress> intBrIps = getCurrentIps(session, INTEGRATION_BRIDGE);
+        boolean result = getCurrentIps(session, node.dataInterface()).isEmpty() &&
+                isInterfaceUp(session, node.dataInterface()) &&
+                intBrIps.contains(node.dataIp().ip()) &&
+                intBrIps.contains(node.localManagementIp().ip()) &&
+                isInterfaceUp(session, INTEGRATION_BRIDGE);
+
+        disconnect(session);
+        return result;
+    }
+
+    private boolean isCurrentStateDone(CordVtnNode node) {
+        switch (node.state()) {
+            case INIT:
+                return deviceService.isAvailable(node.integrationBridgeId());
+            case DEVICE_CREATED:
+                Set<String> activePorts = activePorts(node.integrationBridgeId());
+                return node.systemInterfaces().stream().allMatch(activePorts::contains);
+            case PORT_CREATED:
+                return isIpAddressSet(node);
+            case COMPLETE:
+                return false;
+            default:
+                return false;
+        }
+    }
+
+    private void setState(CordVtnNode node, CordVtnNodeState newState) {
+        if (node.state() == newState) {
+            return;
+        }
+        CordVtnNode updated = updatedState(node, newState);
+        nodeAdminService.updateNode(updated);
+        log.info("Changed {} state: {}", node.hostname(), newState);
+    }
+
+    private void bootstrapNode(CordVtnNode node) {
+        if (isCurrentStateDone(node)) {
+            setState(node, node.state().nextState());
+        } else {
+            node.state().process(this, node);
+        }
+    }
+
+    private class InternalCordVtnNodeListener implements CordVtnNodeListener {
+
+        @Override
+        public void event(CordVtnNodeEvent event) {
+            eventExecutor.execute(() -> {
+                NodeId leader = leadershipService.getLeader(appId.name());
+                if (!Objects.equals(localNodeId, leader)) {
+                    // do not allow to proceed without leadership
+                    return;
+                }
+                handle(event);
+            });
+        }
+
+        private void handle(CordVtnNodeEvent event) {
+            switch (event.type()) {
+                case NODE_CREATED:
+                case NODE_UPDATED:
+                    bootstrapNode(event.subject());
+                    break;
+                case NODE_REMOVED:
+                case NODE_COMPLETE:
+                case NODE_INCOMPLETE:
+                default:
+                    // do nothing
+                    break;
+            }
+        }
+    }
+
+    private void readControllers() {
+        CordVtnConfig config = configService.getConfig(appId, CordVtnConfig.class);
+        if (config == null) {
+            log.warn("No configuration found");
+            return;
+        }
+        controllers = config.controllers();
+        controllers.forEach(ctrl -> {
+            log.debug("Added controller {}:{}", ctrl.ip(), ctrl.port());
+        });
+    }
+
+    private class InternalConfigListener implements NetworkConfigListener {
+
+        @Override
+        public void event(NetworkConfigEvent event) {
+            if (!event.configClass().equals(CordVtnConfig.class)) {
+                return;
+            }
+
+            switch (event.type()) {
+                case CONFIG_ADDED:
+                case CONFIG_UPDATED:
+                    readControllers();
+                    break;
+                default:
+                    break;
+            }
+        }
+    }
+}
diff --git a/src/main/java/org/opencord/cordvtn/impl/CordVtnPipeline.java b/src/main/java/org/opencord/cordvtn/impl/DefaultCordVtnPipeline.java
similarity index 81%
rename from src/main/java/org/opencord/cordvtn/impl/CordVtnPipeline.java
rename to src/main/java/org/opencord/cordvtn/impl/DefaultCordVtnPipeline.java
index af6f27c..812f99c 100644
--- a/src/main/java/org/opencord/cordvtn/impl/CordVtnPipeline.java
+++ b/src/main/java/org/opencord/cordvtn/impl/DefaultCordVtnPipeline.java
@@ -30,13 +30,12 @@
 import org.onosproject.net.AnnotationKeys;
 import org.onosproject.net.Port;
 import org.opencord.cordvtn.api.Constants;
+import org.opencord.cordvtn.api.core.CordVtnPipeline;
 import org.opencord.cordvtn.api.node.CordVtnNode;
 import org.onosproject.core.ApplicationId;
 import org.onosproject.core.CoreService;
-import org.onosproject.net.Device;
 import org.onosproject.net.DeviceId;
 import org.onosproject.net.PortNumber;
-import org.onosproject.net.behaviour.ExtensionTreatmentResolver;
 import org.onosproject.net.device.DeviceService;
 import org.onosproject.net.flow.DefaultFlowRule;
 import org.onosproject.net.flow.DefaultTrafficSelector;
@@ -47,23 +46,20 @@
 import org.onosproject.net.flow.FlowRuleService;
 import org.onosproject.net.flow.TrafficSelector;
 import org.onosproject.net.flow.TrafficTreatment;
-import org.onosproject.net.flow.instructions.ExtensionPropertyException;
-import org.onosproject.net.flow.instructions.ExtensionTreatment;
 import org.slf4j.Logger;
 
-import java.util.Optional;
 
-import static com.google.common.base.Preconditions.checkNotNull;
-import static org.onosproject.net.flow.instructions.ExtensionTreatmentType.ExtensionTreatmentTypes.NICIRA_SET_TUNNEL_DST;
+import static com.google.common.base.Preconditions.checkArgument;
 import static org.opencord.cordvtn.api.Constants.DEFAULT_TUNNEL;
+import static org.opencord.cordvtn.api.node.CordVtnNodeState.COMPLETE;
 import static org.slf4j.LoggerFactory.getLogger;
 
 /**
- * Provides CORD VTN pipeline.
+ * Implementation of cordvtn pipeline.
  */
 @Component(immediate = true)
-@Service(value = CordVtnPipeline.class)
-public final class CordVtnPipeline {
+@Service
+public class DefaultCordVtnPipeline implements CordVtnPipeline {
 
     protected final Logger log = getLogger(getClass());
 
@@ -76,26 +72,7 @@
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     protected DeviceService deviceService;
 
-    // tables
-    public static final int TABLE_ZERO = 0;
-    public static final int TABLE_IN_PORT = 1;
-    public static final int TABLE_ACCESS = 2;
-    public static final int TABLE_IN_SERVICE = 3;
-    public static final int TABLE_DST = 4;
-    public static final int TABLE_TUNNEL_IN = 5;
-    public static final int TABLE_VLAN = 6;
-
-    // priorities
-    public static final int PRIORITY_MANAGEMENT = 55000;
-    public static final int PRIORITY_HIGH = 50000;
-    public static final int PRIORITY_DEFAULT = 5000;
-    public static final int PRIORITY_LOW = 4000;
-    public static final int PRIORITY_ZERO = 0;
-
-    public static final int VXLAN_UDP_PORT = 4789;
-    public static final VlanId VLAN_WAN = VlanId.vlanId((short) 500);
-
-    public static final String PROPERTY_TUNNEL_DST = "tunnelDst";
+    private static final int VXLAN_UDP_PORT = 4789;
 
     private ApplicationId appId;
 
@@ -110,45 +87,45 @@
         log.info("Stopped");
     }
 
-    /**
-     * Flush flows installed by this application.
-     */
-    public void flushRules() {
+    @Override
+    public void cleanupPipeline() {
         flowRuleService.getFlowRulesById(appId).forEach(flowRule -> processFlowRule(false, flowRule));
     }
 
-    /**
-     * Installs table miss rule to a give device.
-     *
-     * @param node cordvtn node
-     */
+    @Override
     public void initPipeline(CordVtnNode node) {
-        checkNotNull(node);
+        checkArgument(node.state() == COMPLETE, "Node is not in COMPLETE state");
 
-        Optional<PortNumber> dataPort = getPortNumber(node.integrationBridgeId(), node.dataIface());
-        Optional<PortNumber> tunnelPort = getPortNumber(node.integrationBridgeId(), DEFAULT_TUNNEL);
-        if (!dataPort.isPresent() || !tunnelPort.isPresent()) {
-            log.warn("Node is not in COMPLETE state");
-            return;
-        }
-
-        Optional<PortNumber> hostMgmtPort = Optional.empty();
-        if (node.hostMgmtIface().isPresent()) {
-            hostMgmtPort = getPortNumber(node.integrationBridgeId(), node.hostMgmtIface().get());
-        }
+        PortNumber dataPort = getPortNumber(node.integrationBridgeId(), node.dataInterface());
+        PortNumber tunnelPort = getPortNumber(node.integrationBridgeId(), DEFAULT_TUNNEL);
+        PortNumber hostMgmtPort = node.hostManagementInterface() == null ?
+                null : getPortNumber(node.integrationBridgeId(), node.hostManagementInterface());
 
         processTableZero(node.integrationBridgeId(),
-                         dataPort.get(),
-                         node.dataIp().ip(),
-                         node.localMgmtIp().ip());
+                dataPort,
+                node.dataIp().ip(),
+                node.localManagementIp().ip());
 
         processInPortTable(node.integrationBridgeId(),
-                           tunnelPort.get(),
-                           dataPort.get(),
-                           hostMgmtPort);
+                tunnelPort,
+                dataPort,
+                hostMgmtPort);
 
-        processAccessTypeTable(node.integrationBridgeId(), dataPort.get());
-        processVlanTable(node.integrationBridgeId(), dataPort.get());
+        processAccessTypeTable(node.integrationBridgeId(), dataPort);
+        processVlanTable(node.integrationBridgeId(), dataPort);
+    }
+
+    @Override
+    public void processFlowRule(boolean install, FlowRule rule) {
+        FlowRuleOperations.Builder oBuilder = FlowRuleOperations.builder();
+        oBuilder = install ? oBuilder.add(rule) : oBuilder.remove(rule);
+
+        flowRuleService.apply(oBuilder.build(new FlowRuleOperationsContext() {
+            @Override
+            public void onError(FlowRuleOperations ops) {
+                log.error(String.format("Failed %s, %s", ops.toString(), rule.toString()));
+            }
+        }));
     }
 
     private void processTableZero(DeviceId deviceId, PortNumber dataPort, IpAddress dataIp,
@@ -380,7 +357,7 @@
     }
 
     private void processInPortTable(DeviceId deviceId, PortNumber tunnelPort, PortNumber dataPort,
-                                    Optional<PortNumber> hostMgmtPort) {
+                                    PortNumber hostMgmtPort) {
         TrafficSelector selector = DefaultTrafficSelector.builder()
                 .matchInPort(tunnelPort)
                 .build();
@@ -421,9 +398,9 @@
 
         processFlowRule(true, flowRule);
 
-        if (hostMgmtPort.isPresent()) {
+        if (hostMgmtPort != null) {
             selector = DefaultTrafficSelector.builder()
-                    .matchInPort(hostMgmtPort.get())
+                    .matchInPort(hostMgmtPort)
                     .build();
 
             treatment = DefaultTrafficTreatment.builder()
@@ -510,43 +487,11 @@
         processFlowRule(true, flowRule);
     }
 
-    public void processFlowRule(boolean install, FlowRule rule) {
-        FlowRuleOperations.Builder oBuilder = FlowRuleOperations.builder();
-        oBuilder = install ? oBuilder.add(rule) : oBuilder.remove(rule);
-
-        flowRuleService.apply(oBuilder.build(new FlowRuleOperationsContext() {
-            @Override
-            public void onError(FlowRuleOperations ops) {
-                log.error(String.format("Failed %s, %s", ops.toString(), rule.toString()));
-            }
-        }));
-    }
-
-    public ExtensionTreatment tunnelDstTreatment(DeviceId deviceId, Ip4Address remoteIp) {
-        Device device = deviceService.getDevice(deviceId);
-        if (device != null && !device.is(ExtensionTreatmentResolver.class)) {
-            log.error("The extension treatment is not supported");
-            return null;
-        }
-
-        ExtensionTreatmentResolver resolver = device.as(ExtensionTreatmentResolver.class);
-        ExtensionTreatment treatment = resolver.getExtensionInstruction(NICIRA_SET_TUNNEL_DST.type());
-        try {
-            treatment.setPropertyValue(PROPERTY_TUNNEL_DST, remoteIp);
-            return treatment;
-        } catch (ExtensionPropertyException e) {
-            log.warn("Failed to get tunnelDst extension treatment for {}", deviceId);
-            return null;
-        }
-    }
-
-    private Optional<PortNumber> getPortNumber(DeviceId deviceId, String portName) {
-        PortNumber port = deviceService.getPorts(deviceId).stream()
+    private PortNumber getPortNumber(DeviceId deviceId, String portName) {
+        return deviceService.getPorts(deviceId).stream()
                 .filter(p -> p.annotations().value(AnnotationKeys.PORT_NAME).equals(portName) &&
                         p.isEnabled())
                 .map(Port::number)
-                .findAny()
-                .orElse(null);
-        return Optional.ofNullable(port);
+                .findAny().orElse(null);
     }
 }
diff --git a/src/main/java/org/opencord/cordvtn/impl/DistributedCordVtnNodeStore.java b/src/main/java/org/opencord/cordvtn/impl/DistributedCordVtnNodeStore.java
new file mode 100644
index 0000000..6bd3875
--- /dev/null
+++ b/src/main/java/org/opencord/cordvtn/impl/DistributedCordVtnNodeStore.java
@@ -0,0 +1,207 @@
+/*
+ * Copyright 2017-present 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.opencord.cordvtn.impl;
+
+import com.google.common.collect.ImmutableSet;
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Reference;
+import org.apache.felix.scr.annotations.ReferenceCardinality;
+import org.apache.felix.scr.annotations.Service;
+import org.onlab.util.KryoNamespace;
+import org.onosproject.core.ApplicationId;
+import org.onosproject.core.CoreService;
+import org.onosproject.store.AbstractStore;
+import org.onosproject.store.serializers.KryoNamespaces;
+import org.onosproject.store.service.ConsistentMap;
+import org.onosproject.store.service.MapEvent;
+import org.onosproject.store.service.MapEventListener;
+import org.onosproject.store.service.Serializer;
+import org.onosproject.store.service.StorageService;
+import org.onosproject.store.service.Versioned;
+import org.opencord.cordvtn.api.net.CidrAddr;
+import org.opencord.cordvtn.api.node.CordVtnNode;
+import org.opencord.cordvtn.api.node.CordVtnNodeEvent;
+import org.opencord.cordvtn.api.node.CordVtnNodeHandler;
+import org.opencord.cordvtn.api.node.CordVtnNodeState;
+import org.opencord.cordvtn.api.node.CordVtnNodeStore;
+import org.opencord.cordvtn.api.node.CordVtnNodeStoreDelegate;
+import org.opencord.cordvtn.api.node.SshAccessInfo;
+import org.slf4j.Logger;
+
+import java.util.Set;
+import java.util.concurrent.ExecutorService;
+import java.util.stream.Collectors;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static java.util.concurrent.Executors.newSingleThreadExecutor;
+import static org.onlab.util.Tools.groupedThreads;
+import static org.opencord.cordvtn.api.Constants.CORDVTN_APP_ID;
+import static org.opencord.cordvtn.api.node.CordVtnNodeState.COMPLETE;
+import static org.slf4j.LoggerFactory.getLogger;
+
+/**
+ * Manages the inventory of cordvtn nodes using a {@link ConsistentMap}.
+ */
+@Component(immediate = true)
+@Service
+public class DistributedCordVtnNodeStore extends AbstractStore<CordVtnNodeEvent, CordVtnNodeStoreDelegate>
+    implements CordVtnNodeStore {
+
+    protected final Logger log = getLogger(getClass());
+
+    private static final String ERR_NOT_FOUND = " does not exist";
+    private static final String ERR_DUPLICATE = " already exists";
+
+    private static final KryoNamespace SERIALIZER_CORDVTN_NODE = KryoNamespace.newBuilder()
+            .register(KryoNamespaces.API)
+            .register(CordVtnNode.class)
+            .register(DefaultCordVtnNode.class)
+            .register(CidrAddr.class)
+            .register(SshAccessInfo.class)
+            .register(CordVtnNodeState.class)
+            .register(CordVtnNodeHandler.class)
+            .register(DefaultCordVtnNodeHandler.class)
+            .build();
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected CoreService coreService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected StorageService storageService;
+
+    private final ExecutorService eventExecutor = newSingleThreadExecutor(
+            groupedThreads(this.getClass().getSimpleName(), "event-handler", log));
+    private final MapEventListener<String, CordVtnNode> nodeStoreListener = new InternalMapListener();
+    private ConsistentMap<String, CordVtnNode> nodeStore;
+
+    @Activate
+    protected void activate() {
+        ApplicationId appId = coreService.registerApplication(CORDVTN_APP_ID);
+        nodeStore = storageService.<String, CordVtnNode>consistentMapBuilder()
+                .withSerializer(Serializer.using(SERIALIZER_CORDVTN_NODE))
+                .withName("cordvtn-nodestore")
+                .withApplicationId(appId)
+                .build();
+        nodeStore.addListener(nodeStoreListener);
+        log.info("Started");
+    }
+
+    @Deactivate
+    protected void deactivate() {
+        nodeStore.removeListener(nodeStoreListener);
+        log.info("Stopped");
+    }
+
+    @Override
+    public Set<CordVtnNode> nodes() {
+        Set<CordVtnNode> nodes = nodeStore.values().stream()
+                .map(Versioned::value)
+                .collect(Collectors.toSet());
+        return ImmutableSet.copyOf(nodes);
+    }
+
+    @Override
+    public CordVtnNode node(String hostname) {
+        Versioned<CordVtnNode> versioned = nodeStore.get(hostname);
+        return versioned == null ? null : versioned.value();
+    }
+
+    @Override
+    public void createNode(CordVtnNode node) {
+        nodeStore.compute(node.hostname(), (hostname, existing) -> {
+            final String error = node.hostname() + ERR_DUPLICATE;
+            checkArgument(existing == null, error);
+            return node;
+        });
+    }
+
+    @Override
+    public void updateNode(CordVtnNode node) {
+        nodeStore.compute(node.hostname(), (hostname, existing) -> {
+            final String error = node.hostname() + ERR_NOT_FOUND;
+            checkArgument(existing != null, error);
+            return node;
+        });
+    }
+
+    @Override
+    public CordVtnNode removeNode(String hostname) {
+        Versioned<CordVtnNode> removed = nodeStore.remove(hostname);
+        return removed == null ? null : removed.value();
+    }
+
+    private class InternalMapListener implements MapEventListener<String, CordVtnNode> {
+
+        @Override
+        public void event(MapEvent<String, CordVtnNode> event) {
+            switch (event.type()) {
+                case INSERT:
+                    log.debug("CordVtn node is created {}", event.newValue().value());
+                    eventExecutor.execute(() -> {
+                        notifyDelegate(new CordVtnNodeEvent(
+                                CordVtnNodeEvent.Type.NODE_CREATED,
+                                event.newValue().value()
+                        ));
+                        if (event.newValue().value().state() == COMPLETE) {
+                            notifyDelegate(new CordVtnNodeEvent(
+                                    CordVtnNodeEvent.Type.NODE_COMPLETE,
+                                    event.newValue().value()
+                            ));
+                        }
+                    });
+                    break;
+                case UPDATE:
+                    log.debug("CordVtn node is updated {}", event.newValue().value());
+                    eventExecutor.execute(() -> {
+                        notifyDelegate(new CordVtnNodeEvent(
+                                CordVtnNodeEvent.Type.NODE_UPDATED,
+                                event.newValue().value()
+                        ));
+                        processUpdated(event.oldValue().value(), event.newValue().value());
+                    });
+                    break;
+                case REMOVE:
+                    log.debug("CordVtn node is removed {}", event.oldValue().value());
+                    eventExecutor.execute(() -> {
+                        notifyDelegate(new CordVtnNodeEvent(
+                                CordVtnNodeEvent.Type.NODE_REMOVED,
+                                event.oldValue().value()
+                        ));
+                    });
+                    break;
+                default:
+                    // do nothing
+                    break;
+            }
+        }
+
+        private void processUpdated(CordVtnNode oldNode, CordVtnNode newNode) {
+            if (oldNode.state() != COMPLETE && newNode.state() == COMPLETE) {
+                notifyDelegate(new CordVtnNodeEvent(
+                        CordVtnNodeEvent.Type.NODE_COMPLETE,
+                        newNode
+                ));
+            } else if (oldNode.state() == COMPLETE && newNode.state() != COMPLETE) {
+                notifyDelegate(new CordVtnNodeEvent(
+                        CordVtnNodeEvent.Type.NODE_INCOMPLETE,
+                        newNode
+                ));
+            }
+        }
+    }
+}
diff --git a/src/main/java/org/opencord/cordvtn/impl/DistributedServiceNetworkStore.java b/src/main/java/org/opencord/cordvtn/impl/DistributedServiceNetworkStore.java
index dc98ced..212a90e 100644
--- a/src/main/java/org/opencord/cordvtn/impl/DistributedServiceNetworkStore.java
+++ b/src/main/java/org/opencord/cordvtn/impl/DistributedServiceNetworkStore.java
@@ -95,7 +95,7 @@
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     protected StorageService storageService;
 
-   private final ExecutorService eventExecutor = newSingleThreadExecutor(
+    private final ExecutorService eventExecutor = newSingleThreadExecutor(
             groupedThreads(this.getClass().getSimpleName(), "event-handler", log));
     private final MapEventListener<PortId, ServicePort> servicePortListener =
             new ServicePortMapListener();
@@ -108,7 +108,6 @@
     @Activate
     protected void activate() {
         ApplicationId appId = coreService.registerApplication(CORDVTN_APP_ID);
-
         serviceNetworkStore = storageService.<NetworkId, ServiceNetwork>consistentMapBuilder()
                 .withSerializer(Serializer.using(SERIALIZER_SERVICE))
                 .withName("cordvtn-servicenetstore")
diff --git a/src/main/java/org/opencord/cordvtn/impl/InstanceManager.java b/src/main/java/org/opencord/cordvtn/impl/InstanceManager.java
index e8983c6..bd5e528 100644
--- a/src/main/java/org/opencord/cordvtn/impl/InstanceManager.java
+++ b/src/main/java/org/opencord/cordvtn/impl/InstanceManager.java
@@ -268,23 +268,26 @@
 
         @Override
         public void event(ServiceNetworkEvent event) {
-            NodeId leader = leadershipService.getLeader(appId.name());
-            if (!Objects.equals(localNodeId, leader)) {
-                // do not allow to proceed without leadership
-                return;
-            }
+            eventExecutor.execute(() -> {
+                NodeId leader = leadershipService.getLeader(appId.name());
+                if (!Objects.equals(localNodeId, leader)) {
+                    // do not allow to proceed without leadership
+                    return;
+                }
+                handle(event);
+            });
+        }
 
+        private void handle(ServiceNetworkEvent event) {
             switch (event.type()) {
                 case SERVICE_PORT_CREATED:
                 case SERVICE_PORT_UPDATED:
                     log.debug("Processing service port {}", event.servicePort());
                     PortId portId = event.servicePort().id();
-                    eventExecutor.execute(() -> {
-                        Instance instance = getInstance(portId);
-                        if (instance != null) {
-                            addInstance(instance.host().location());
-                        }
-                    });
+                    Instance instance = getInstance(portId);
+                    if (instance != null) {
+                        addInstance(instance.host().location());
+                    }
                     break;
                 case SERVICE_PORT_REMOVED:
                 case SERVICE_NETWORK_CREATED:
diff --git a/src/main/java/org/opencord/cordvtn/impl/handler/AbstractInstanceHandler.java b/src/main/java/org/opencord/cordvtn/impl/handler/AbstractInstanceHandler.java
index 64cda2e..59cb7f7 100644
--- a/src/main/java/org/opencord/cordvtn/impl/handler/AbstractInstanceHandler.java
+++ b/src/main/java/org/opencord/cordvtn/impl/handler/AbstractInstanceHandler.java
@@ -18,11 +18,21 @@
 import com.google.common.collect.ImmutableSet;
 import org.onlab.osgi.DefaultServiceDirectory;
 import org.onlab.osgi.ServiceDirectory;
+import org.onlab.packet.Ip4Address;
+import org.onlab.packet.IpAddress;
 import org.onlab.util.Tools;
 import org.onosproject.core.ApplicationId;
 import org.onosproject.core.CoreService;
 import org.onosproject.mastership.MastershipService;
+import org.onosproject.net.Device;
+import org.onosproject.net.DeviceId;
 import org.onosproject.net.Host;
+import org.onosproject.net.Port;
+import org.onosproject.net.PortNumber;
+import org.onosproject.net.behaviour.ExtensionTreatmentResolver;
+import org.onosproject.net.device.DeviceService;
+import org.onosproject.net.flow.instructions.ExtensionPropertyException;
+import org.onosproject.net.flow.instructions.ExtensionTreatment;
 import org.onosproject.net.host.HostEvent;
 import org.onosproject.net.host.HostListener;
 import org.onosproject.net.host.HostService;
@@ -33,15 +43,21 @@
 import org.opencord.cordvtn.api.net.NetworkId;
 import org.opencord.cordvtn.api.net.ServiceNetwork;
 import org.opencord.cordvtn.api.net.ServicePort;
+import org.opencord.cordvtn.api.node.CordVtnNode;
+import org.opencord.cordvtn.api.node.CordVtnNodeService;
 import org.slf4j.Logger;
 
 import java.util.Objects;
+import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.ExecutorService;
 import java.util.stream.Collectors;
 
 import static java.util.concurrent.Executors.newSingleThreadExecutor;
 import static org.onlab.util.Tools.groupedThreads;
+import static org.onosproject.net.AnnotationKeys.PORT_NAME;
+import static org.onosproject.net.flow.instructions.ExtensionTreatmentType.ExtensionTreatmentTypes.NICIRA_SET_TUNNEL_DST;
+import static org.opencord.cordvtn.api.Constants.DEFAULT_TUNNEL;
 import static org.slf4j.LoggerFactory.getLogger;
 
 /**
@@ -53,11 +69,14 @@
 
     protected static final String ERR_VTN_NETWORK = "Failed to get VTN network for %s";
     protected static final String ERR_VTN_PORT = "Failed to get VTN port for %s";
+    protected static final String PROPERTY_TUNNEL_DST = "tunnelDst";
 
     protected CoreService coreService;
     protected MastershipService mastershipService;
     protected HostService hostService;
+    protected DeviceService deviceService;
     protected ServiceNetworkService snetService;
+    protected CordVtnNodeService nodeService;
     protected ApplicationId appId;
     protected Set<ServiceNetwork.NetworkType> netTypes = ImmutableSet.of();
 
@@ -71,7 +90,9 @@
         coreService = services.get(CoreService.class);
         mastershipService = services.get(MastershipService.class);
         hostService = services.get(HostService.class);
+        deviceService = services.get(DeviceService.class);
         snetService = services.get(ServiceNetworkService.class);
+        nodeService = services.get(CordVtnNodeService.class);
 
         appId = coreService.registerApplication(Constants.CORDVTN_APP_ID);
         hostService.addListener(hostListener);
@@ -118,6 +139,75 @@
         return sport;
     }
 
+    protected PortNumber dataPort(DeviceId deviceId) {
+        CordVtnNode node = nodeService.node(deviceId);
+        if (node == null) {
+            log.debug("Failed to get node for {}", deviceId);
+            return null;
+        }
+        Optional<PortNumber> port = getPortNumber(deviceId, node.dataInterface());
+        return port.isPresent() ? port.get() : null;
+
+    }
+
+    protected PortNumber tunnelPort(DeviceId deviceId) {
+        Optional<PortNumber> port = getPortNumber(deviceId, DEFAULT_TUNNEL);
+        return port.isPresent() ? port.get() : null;
+    }
+
+    protected PortNumber hostManagementPort(DeviceId deviceId) {
+        CordVtnNode node = nodeService.node(deviceId);
+        if (node == null) {
+            log.debug("Failed to get node for {}", deviceId);
+            return null;
+        }
+
+        if (node.hostManagementInterface() != null) {
+            Optional<PortNumber> port =
+                    getPortNumber(deviceId, node.hostManagementInterface());
+            return port.isPresent() ? port.get() : null;
+        } else {
+            return null;
+        }
+    }
+
+    protected ExtensionTreatment tunnelDstTreatment(DeviceId deviceId, Ip4Address remoteIp) {
+        Device device = deviceService.getDevice(deviceId);
+        if (device != null && !device.is(ExtensionTreatmentResolver.class)) {
+            log.error("The extension treatment is not supported");
+            return null;
+        }
+
+        ExtensionTreatmentResolver resolver = device.as(ExtensionTreatmentResolver.class);
+        ExtensionTreatment treatment = resolver.getExtensionInstruction(NICIRA_SET_TUNNEL_DST.type());
+        try {
+            treatment.setPropertyValue(PROPERTY_TUNNEL_DST, remoteIp);
+            return treatment;
+        } catch (ExtensionPropertyException e) {
+            log.warn("Failed to get tunnelDst extension treatment for {}", deviceId);
+            return null;
+        }
+    }
+
+    protected IpAddress dataIp(DeviceId deviceId) {
+        CordVtnNode node = nodeService.node(deviceId);
+        if (node == null) {
+            log.debug("Failed to get node for {}", deviceId);
+            return null;
+        }
+        return node.dataIp().ip();
+    }
+
+    private Optional<PortNumber> getPortNumber(DeviceId deviceId, String portName) {
+        PortNumber port = deviceService.getPorts(deviceId).stream()
+                .filter(p -> p.annotations().value(PORT_NAME).equals(portName) &&
+                        p.isEnabled())
+                .map(Port::number)
+                .findAny()
+                .orElse(null);
+        return Optional.ofNullable(port);
+    }
+
     private class InternalHostListener implements HostListener {
 
         @Override
diff --git a/src/main/java/org/opencord/cordvtn/impl/handler/AccessAgentInstanceHandler.java b/src/main/java/org/opencord/cordvtn/impl/handler/AccessAgentInstanceHandler.java
index 460ba25..82de7fc 100644
--- a/src/main/java/org/opencord/cordvtn/impl/handler/AccessAgentInstanceHandler.java
+++ b/src/main/java/org/opencord/cordvtn/impl/handler/AccessAgentInstanceHandler.java
@@ -28,10 +28,11 @@
 import org.onosproject.net.flow.FlowRule;
 import org.onosproject.net.flow.TrafficSelector;
 import org.onosproject.net.flow.TrafficTreatment;
+import org.opencord.cordvtn.api.core.CordVtnPipeline;
 import org.opencord.cordvtn.api.core.Instance;
 import org.opencord.cordvtn.api.core.InstanceHandler;
-import org.opencord.cordvtn.impl.CordVtnNodeManager;
-import org.opencord.cordvtn.impl.CordVtnPipeline;
+import org.opencord.cordvtn.api.core.ServiceNetworkService;
+import org.opencord.cordvtn.api.node.CordVtnNodeService;
 
 import static org.opencord.cordvtn.api.net.ServiceNetwork.NetworkType.ACCESS_AGENT;
 
@@ -42,10 +43,13 @@
 public class AccessAgentInstanceHandler extends AbstractInstanceHandler implements InstanceHandler {
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    protected CordVtnPipeline pipeline;
+    protected ServiceNetworkService snetService;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    protected CordVtnNodeManager nodeManager;
+    protected CordVtnNodeService nodeService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected CordVtnPipeline pipeline;
 
     @Activate
     protected void activate() {
@@ -96,7 +100,7 @@
                 .build();
 
         treatment = DefaultTrafficTreatment.builder()
-                .setOutput(nodeManager.dataPort(instance.deviceId()))
+                .setOutput(dataPort(instance.deviceId()))
                 .build();
 
         flowRule = DefaultFlowRule.builder()
diff --git a/src/main/java/org/opencord/cordvtn/impl/handler/DefaultInstanceHandler.java b/src/main/java/org/opencord/cordvtn/impl/handler/DefaultInstanceHandler.java
index 3f68c22..8279d34 100644
--- a/src/main/java/org/opencord/cordvtn/impl/handler/DefaultInstanceHandler.java
+++ b/src/main/java/org/opencord/cordvtn/impl/handler/DefaultInstanceHandler.java
@@ -47,15 +47,16 @@
 import org.onosproject.net.flow.instructions.L2ModificationInstruction;
 import org.onosproject.net.host.DefaultHostDescription;
 import org.onosproject.net.host.HostDescription;
+import org.opencord.cordvtn.api.core.CordVtnPipeline;
 import org.opencord.cordvtn.api.core.Instance;
 import org.opencord.cordvtn.api.core.InstanceHandler;
 import org.opencord.cordvtn.api.core.InstanceService;
+import org.opencord.cordvtn.api.core.ServiceNetworkService;
 import org.opencord.cordvtn.api.net.AddressPair;
 import org.opencord.cordvtn.api.net.ServiceNetwork;
 import org.opencord.cordvtn.api.net.ServicePort;
 import org.opencord.cordvtn.api.node.CordVtnNode;
-import org.opencord.cordvtn.impl.CordVtnNodeManager;
-import org.opencord.cordvtn.impl.CordVtnPipeline;
+import org.opencord.cordvtn.api.node.CordVtnNodeService;
 
 import java.util.Set;
 import java.util.stream.Collectors;
@@ -74,10 +75,13 @@
     protected FlowRuleService flowRuleService;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    protected CordVtnPipeline pipeline;
+    protected ServiceNetworkService snetService;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    protected CordVtnNodeManager nodeManager;
+    protected CordVtnNodeService nodeService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected CordVtnPipeline pipeline;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     protected InstanceService instanceService;
@@ -95,10 +99,10 @@
 
     @Override
     public void instanceDetected(Instance instance) {
+        log.info("Instance is detected or updated {}", instance);
         if (instance.isAdditionalInstance()) {
             return;
         }
-        log.info("Instance is detected or updated {}", instance);
 
         ServiceNetwork snet = getServiceNetwork(instance);
         populateDefaultRules(instance, snet, true);
@@ -109,7 +113,7 @@
             populateVlanRule(
                     instance,
                     sport.vlanId(),
-                    nodeManager.dataPort(instance.deviceId()),
+                    dataPort(instance.deviceId()),
                     true);
         }
         // FIXME don't add the existing instance again
@@ -138,7 +142,7 @@
             populateVlanRule(
                     instance,
                     sport.vlanId(),
-                    nodeManager.dataPort(instance.deviceId()),
+                    dataPort(instance.deviceId()),
                     false);
         }
         boolean isOriginalInstance = !instance.isAdditionalInstance();
@@ -246,7 +250,7 @@
     }
 
     private void populateDstIpRule(Instance instance, long vni, boolean install) {
-        Ip4Address tunnelIp = nodeManager.dataIp(instance.deviceId()).getIp4Address();
+        Ip4Address tunnelIp = dataIp(instance.deviceId()).getIp4Address();
 
         TrafficSelector selector = DefaultTrafficSelector.builder()
                 .matchEthType(Ethernet.TYPE_IPV4)
@@ -270,13 +274,13 @@
 
         pipeline.processFlowRule(install, flowRule);
 
-        for (CordVtnNode node : nodeManager.completeNodes()) {
+        for (CordVtnNode node : nodeService.completeNodes()) {
             if (node.integrationBridgeId().equals(instance.deviceId())) {
                 continue;
             }
 
             ExtensionTreatment tunnelDst =
-                    pipeline.tunnelDstTreatment(node.integrationBridgeId(), tunnelIp);
+                    tunnelDstTreatment(node.integrationBridgeId(), tunnelIp);
             if (tunnelDst == null) {
                 continue;
             }
@@ -285,7 +289,7 @@
                     .setEthDst(instance.mac())
                     .setTunnelId(vni)
                     .extension(tunnelDst, node.integrationBridgeId())
-                    .setOutput(nodeManager.tunnelPort(node.integrationBridgeId()))
+                    .setOutput(tunnelPort(node.integrationBridgeId()))
                     .build();
 
             flowRule = DefaultFlowRule.builder()
@@ -337,7 +341,7 @@
                 .build();
 
 
-        nodeManager.completeNodes().forEach(node -> {
+        nodeService.completeNodes().forEach(node -> {
             FlowRule flowRuleDirect = DefaultFlowRule.builder()
                     .fromApp(appId)
                     .withSelector(selector)
@@ -362,7 +366,7 @@
                 .drop()
                 .build();
 
-        nodeManager.completeNodes().forEach(node -> {
+        nodeService.completeNodes().forEach(node -> {
             FlowRule flowRuleDirect = DefaultFlowRule.builder()
                     .fromApp(appId)
                     .withSelector(selector)
diff --git a/src/main/java/org/opencord/cordvtn/impl/handler/DependencyHandler.java b/src/main/java/org/opencord/cordvtn/impl/handler/DependencyHandler.java
index 772e1bc..ba63cdd 100644
--- a/src/main/java/org/opencord/cordvtn/impl/handler/DependencyHandler.java
+++ b/src/main/java/org/opencord/cordvtn/impl/handler/DependencyHandler.java
@@ -50,16 +50,16 @@
 import org.onosproject.net.group.GroupDescription;
 import org.onosproject.net.group.GroupKey;
 import org.onosproject.net.group.GroupService;
+import org.opencord.cordvtn.api.core.CordVtnPipeline;
 import org.opencord.cordvtn.api.core.Instance;
-import org.opencord.cordvtn.api.core.ServiceNetworkAdminService;
 import org.opencord.cordvtn.api.core.ServiceNetworkEvent;
 import org.opencord.cordvtn.api.core.ServiceNetworkListener;
+import org.opencord.cordvtn.api.core.ServiceNetworkService;
 import org.opencord.cordvtn.api.net.NetworkId;
 import org.opencord.cordvtn.api.net.ServiceNetwork;
 import org.opencord.cordvtn.api.net.ServiceNetwork.DependencyType;
 import org.opencord.cordvtn.api.node.CordVtnNode;
-import org.opencord.cordvtn.impl.CordVtnNodeManager;
-import org.opencord.cordvtn.impl.CordVtnPipeline;
+import org.opencord.cordvtn.api.node.CordVtnNodeService;
 import org.slf4j.Logger;
 
 import java.util.List;
@@ -69,9 +69,9 @@
 import java.util.stream.Collectors;
 
 import static org.onosproject.net.group.DefaultGroupBucket.createSelectGroupBucket;
+import static org.opencord.cordvtn.api.core.CordVtnPipeline.*;
 import static org.opencord.cordvtn.api.net.ServiceNetwork.DependencyType.BIDIRECTIONAL;
 import static org.opencord.cordvtn.api.net.ServiceNetwork.NetworkType.*;
-import static org.opencord.cordvtn.impl.CordVtnPipeline.*;
 import static org.slf4j.LoggerFactory.getLogger;
 
 /**
@@ -97,14 +97,14 @@
     protected ClusterService clusterService;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected ServiceNetworkService snetService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected CordVtnNodeService nodeService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     protected CordVtnPipeline pipeline;
 
-    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    protected CordVtnNodeManager nodeManager;
-
-    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    protected ServiceNetworkAdminService snetService;
-
     private final ServiceNetworkListener snetListener = new InternalServiceNetworkListener();
     private NodeId localNodeId;
 
@@ -172,7 +172,7 @@
     }
 
     private void updateProviderInstances(ServiceNetwork provider) {
-        Set<DeviceId> devices = nodeManager.completeNodes().stream()
+        Set<DeviceId> devices = nodeService.completeNodes().stream()
                 .map(CordVtnNode::integrationBridgeId)
                 .collect(Collectors.toSet());
 
@@ -239,7 +239,7 @@
 
     private void removeGroup(NetworkId netId) {
         GroupKey groupKey = getGroupKey(netId);
-        nodeManager.completeNodes().forEach(node -> {
+        nodeService.completeNodes().forEach(node -> {
             DeviceId deviceId = node.integrationBridgeId();
             Group group = groupService.getGroup(deviceId, groupKey);
             if (group != null) {
@@ -285,7 +285,7 @@
         Map<DeviceId, GroupId> providerGroups = Maps.newHashMap();
         Map<DeviceId, Set<PortNumber>> subscriberPorts = Maps.newHashMap();
 
-        nodeManager.completeNodes().forEach(node -> {
+        nodeService.completeNodes().forEach(node -> {
             DeviceId deviceId = node.integrationBridgeId();
             GroupId groupId = getProviderGroup(provider, deviceId);
             providerGroups.put(deviceId, groupId);
@@ -355,7 +355,7 @@
                 .transition(TABLE_DST)
                 .build();
 
-        nodeManager.completeNodes().forEach(node -> {
+        nodeService.completeNodes().forEach(node -> {
             DeviceId deviceId = node.integrationBridgeId();
             FlowRule flowRuleDirect = DefaultFlowRule.builder()
                     .fromApp(appId)
@@ -409,7 +409,7 @@
                                                  Set<Instance> instances) {
         List<GroupBucket> buckets = Lists.newArrayList();
         instances.forEach(instance -> {
-            Ip4Address tunnelIp = nodeManager.dataIp(instance.deviceId()).getIp4Address();
+            Ip4Address tunnelIp = dataIp(instance.deviceId()).getIp4Address();
 
             if (deviceId.equals(instance.deviceId())) {
                 TrafficTreatment treatment = DefaultTrafficTreatment.builder()
@@ -418,13 +418,12 @@
                         .build();
                 buckets.add(createSelectGroupBucket(treatment));
             } else {
-                ExtensionTreatment tunnelDst =
-                        pipeline.tunnelDstTreatment(deviceId, tunnelIp);
+                ExtensionTreatment tunnelDst = tunnelDstTreatment(deviceId, tunnelIp);
                 TrafficTreatment treatment = DefaultTrafficTreatment.builder()
                         .setEthDst(instance.mac())
                         .extension(tunnelDst, deviceId)
                         .setTunnelId(tunnelId)
-                        .setOutput(nodeManager.tunnelPort(instance.deviceId()))
+                        .setOutput(tunnelPort(instance.deviceId()))
                         .build();
                 buckets.add(createSelectGroupBucket(treatment));
             }
@@ -435,33 +434,30 @@
     private class InternalServiceNetworkListener implements ServiceNetworkListener {
 
         @Override
-        public boolean isRelevant(ServiceNetworkEvent event) {
-            // do not allow to proceed without leadership
-            NodeId leader = leadershipService.getLeader(appId.name());
-            return Objects.equals(localNodeId, leader);
+        public void event(ServiceNetworkEvent event) {
+            eventExecutor.execute(() -> {
+                NodeId leader = leadershipService.getLeader(appId.name());
+                if (!Objects.equals(localNodeId, leader)) {
+                    // do not allow to proceed without leadership
+                    return;
+                }
+                handle(event);
+            });
         }
 
-        @Override
-        public void event(ServiceNetworkEvent event) {
-
+        private void handle(ServiceNetworkEvent event) {
             switch (event.type()) {
                 case SERVICE_NETWORK_PROVIDER_ADDED:
                     log.debug("Dependency added: {}", event);
-                    eventExecutor.execute(() -> {
-                        dependencyAdded(
-                                event.subject(),
-                                event.provider().provider(),
-                                event.provider().type());
-                    });
+                    dependencyAdded(event.subject(),
+                            event.provider().provider(),
+                            event.provider().type());
                     break;
                 case SERVICE_NETWORK_PROVIDER_REMOVED:
                     log.debug("Dependency removed: {}", event);
-                    eventExecutor.execute(() -> {
-                        dependencyRemoved(
-                                event.subject(),
-                                event.provider().provider(),
-                                event.provider().type());
-                    });
+                    dependencyRemoved(event.subject(),
+                            event.provider().provider(),
+                            event.provider().type());
                     break;
                 case SERVICE_NETWORK_CREATED:
                 case SERVICE_NETWORK_UPDATED:
diff --git a/src/main/java/org/opencord/cordvtn/impl/handler/ManagementInstanceHandler.java b/src/main/java/org/opencord/cordvtn/impl/handler/ManagementInstanceHandler.java
index 0475f07..aea5da2 100644
--- a/src/main/java/org/opencord/cordvtn/impl/handler/ManagementInstanceHandler.java
+++ b/src/main/java/org/opencord/cordvtn/impl/handler/ManagementInstanceHandler.java
@@ -29,11 +29,12 @@
 import org.onosproject.net.flow.FlowRule;
 import org.onosproject.net.flow.TrafficSelector;
 import org.onosproject.net.flow.TrafficTreatment;
+import org.opencord.cordvtn.api.core.CordVtnPipeline;
 import org.opencord.cordvtn.api.core.Instance;
 import org.opencord.cordvtn.api.core.InstanceHandler;
+import org.opencord.cordvtn.api.core.ServiceNetworkService;
 import org.opencord.cordvtn.api.net.ServiceNetwork;
-import org.opencord.cordvtn.impl.CordVtnNodeManager;
-import org.opencord.cordvtn.impl.CordVtnPipeline;
+import org.opencord.cordvtn.api.node.CordVtnNodeService;
 
 import static org.opencord.cordvtn.api.net.ServiceNetwork.NetworkType.MANAGEMENT_HOST;
 import static org.opencord.cordvtn.api.net.ServiceNetwork.NetworkType.MANAGEMENT_LOCAL;
@@ -46,10 +47,13 @@
 public class ManagementInstanceHandler extends AbstractInstanceHandler implements InstanceHandler {
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    protected CordVtnPipeline pipeline;
+    protected ServiceNetworkService snetService;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
-    protected CordVtnNodeManager nodeManager;
+    protected CordVtnNodeService nodeService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected CordVtnPipeline pipeline;
 
     @Activate
     protected void activate() {
@@ -123,7 +127,7 @@
     }
 
     private void populateHostsManagementRules(Instance instance, boolean install) {
-        PortNumber hostMgmtPort = nodeManager.hostManagementPort(instance.deviceId());
+        PortNumber hostMgmtPort = hostManagementPort(instance.deviceId());
         if (hostMgmtPort == null) {
             log.warn("Can not find host management port in {}", instance.deviceId());
             return;