diff --git a/app/src/main/java/org/opencord/olt/impl/Olt.java b/app/src/main/java/org/opencord/olt/impl/Olt.java
new file mode 100644
index 0000000..5e9a413
--- /dev/null
+++ b/app/src/main/java/org/opencord/olt/impl/Olt.java
@@ -0,0 +1,578 @@
+/*
+ * Copyright 2016-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.olt.impl;
+
+import com.google.common.collect.Maps;
+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.Modified;
+import org.apache.felix.scr.annotations.Property;
+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.EthType;
+import org.onlab.packet.VlanId;
+import org.onosproject.cfg.ComponentConfigService;
+import org.onosproject.cordconfig.access.AccessDeviceConfig;
+import org.onosproject.cordconfig.access.AccessDeviceData;
+import org.onosproject.core.ApplicationId;
+import org.onosproject.core.CoreService;
+import org.onosproject.event.AbstractListenerManager;
+import org.onosproject.mastership.MastershipService;
+import org.onosproject.net.ConnectPoint;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.Port;
+import org.onosproject.net.PortNumber;
+import org.onosproject.net.config.ConfigFactory;
+import org.onosproject.net.config.NetworkConfigEvent;
+import org.onosproject.net.config.NetworkConfigListener;
+import org.onosproject.net.config.NetworkConfigRegistry;
+import org.onosproject.net.config.basics.SubjectFactories;
+import org.onosproject.net.device.DeviceEvent;
+import org.onosproject.net.device.DeviceListener;
+import org.onosproject.net.device.DeviceService;
+import org.onosproject.net.flow.DefaultTrafficSelector;
+import org.onosproject.net.flow.DefaultTrafficTreatment;
+import org.onosproject.net.flow.TrafficSelector;
+import org.onosproject.net.flow.TrafficTreatment;
+import org.onosproject.net.flow.criteria.Criteria;
+import org.onosproject.net.flowobjective.DefaultFilteringObjective;
+import org.onosproject.net.flowobjective.DefaultForwardingObjective;
+import org.onosproject.net.flowobjective.FilteringObjective;
+import org.onosproject.net.flowobjective.FlowObjectiveService;
+import org.onosproject.net.flowobjective.ForwardingObjective;
+import org.onosproject.net.flowobjective.Objective;
+import org.onosproject.net.flowobjective.ObjectiveContext;
+import org.onosproject.net.flowobjective.ObjectiveError;
+import org.opencord.olt.AccessDeviceEvent;
+import org.opencord.olt.AccessDeviceListener;
+import org.opencord.olt.AccessDeviceService;
+import org.onosproject.store.serializers.KryoNamespaces;
+import org.onosproject.store.service.Serializer;
+import org.onosproject.store.service.StorageService;
+import org.osgi.service.component.ComponentContext;
+import org.slf4j.Logger;
+
+import java.util.Collection;
+import java.util.Dictionary;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Properties;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+import static com.google.common.base.Strings.isNullOrEmpty;
+import static org.onlab.util.Tools.get;
+import static org.onlab.util.Tools.groupedThreads;
+import static org.slf4j.LoggerFactory.getLogger;
+
+/**
+ * Provisions rules on access devices.
+ */
+@Service
+@Component(immediate = true)
+public class Olt
+        extends AbstractListenerManager<AccessDeviceEvent, AccessDeviceListener>
+        implements AccessDeviceService {
+
+    private static final short DEFAULT_VLAN = 0;
+    private static final String SUBSCRIBERS = "existing-subscribers";
+
+    private final Logger log = getLogger(getClass());
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected FlowObjectiveService flowObjectiveService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected MastershipService mastershipService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected DeviceService deviceService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected CoreService coreService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected NetworkConfigRegistry networkConfig;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected ComponentConfigService componentConfigService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected StorageService storageService;
+
+    @Property(name = "defaultVlan", intValue = DEFAULT_VLAN,
+            label = "Default VLAN RG<->ONU traffic")
+    private int defaultVlan = DEFAULT_VLAN;
+
+    private final DeviceListener deviceListener = new InternalDeviceListener();
+
+    private ApplicationId appId;
+
+    private ExecutorService oltInstallers = Executors.newFixedThreadPool(4,
+                                                                         groupedThreads("onos/olt-service",
+                                                                                        "olt-installer-%d"));
+
+    private Map<DeviceId, AccessDeviceData> oltData = new ConcurrentHashMap<>();
+
+    private Map<ConnectPoint, VlanId> subscribers;
+
+    private InternalNetworkConfigListener configListener =
+            new InternalNetworkConfigListener();
+    private static final Class<AccessDeviceConfig> CONFIG_CLASS =
+            AccessDeviceConfig.class;
+
+    private ConfigFactory<DeviceId, AccessDeviceConfig> configFactory =
+            new ConfigFactory<DeviceId, AccessDeviceConfig>(
+                    SubjectFactories.DEVICE_SUBJECT_FACTORY, CONFIG_CLASS, "accessDevice") {
+                @Override
+                public AccessDeviceConfig createConfig() {
+                    return new AccessDeviceConfig();
+                }
+            };
+
+
+    @Activate
+    public void activate(ComponentContext context) {
+        modified(context);
+        appId = coreService.registerApplication("org.onosproject.olt");
+        componentConfigService.registerProperties(getClass());
+
+        eventDispatcher.addSink(AccessDeviceEvent.class, listenerRegistry);
+
+        networkConfig.registerConfigFactory(configFactory);
+        networkConfig.addListener(configListener);
+
+
+        networkConfig.getSubjects(DeviceId.class, AccessDeviceConfig.class).forEach(
+                subject -> {
+                    AccessDeviceConfig config = networkConfig.getConfig(subject, AccessDeviceConfig.class);
+                    if (config != null) {
+                        AccessDeviceData data = config.getOlt();
+                        oltData.put(data.deviceId(), data);
+                    }
+                }
+        );
+
+        oltData.keySet().stream()
+                .flatMap(did -> deviceService.getPorts(did).stream())
+                .filter(p -> !oltData.get(p.element().id()).uplink().equals(p.number()))
+                .filter(p -> p.isEnabled())
+                .forEach(p -> processFilteringObjectives((DeviceId) p.element().id(),
+                                                         p.number(), true));
+
+        subscribers = storageService.<ConnectPoint, VlanId>consistentMapBuilder()
+                .withName(SUBSCRIBERS)
+                .withSerializer(Serializer.using(KryoNamespaces.API))
+                .build().asJavaMap();
+
+        deviceService.addListener(deviceListener);
+
+        log.info("Started with Application ID {}", appId.id());
+    }
+
+    @Deactivate
+    public void deactivate() {
+        componentConfigService.unregisterProperties(getClass(), false);
+        deviceService.removeListener(deviceListener);
+        networkConfig.removeListener(configListener);
+        networkConfig.unregisterConfigFactory(configFactory);
+        log.info("Stopped");
+    }
+
+    @Modified
+    public void modified(ComponentContext context) {
+        Dictionary<?, ?> properties = context != null ? context.getProperties() : new Properties();
+
+        try {
+            String s = get(properties, "defaultVlan");
+            defaultVlan = isNullOrEmpty(s) ? DEFAULT_VLAN : Integer.parseInt(s.trim());
+        } catch (Exception e) {
+            defaultVlan = DEFAULT_VLAN;
+        }
+    }
+
+    @Override
+    public void provisionSubscriber(ConnectPoint port, VlanId vlan) {
+        AccessDeviceData olt = oltData.get(port.deviceId());
+
+        if (olt == null) {
+            log.warn("No data found for OLT device {}", port.deviceId());
+            return;
+        }
+
+        provisionVlans(olt.deviceId(), olt.uplink(), port.port(), vlan, olt.vlan(),
+                       olt.defaultVlan());
+    }
+
+    @Override
+    public void removeSubscriber(ConnectPoint port) {
+        AccessDeviceData olt = oltData.get(port.deviceId());
+
+        if (olt == null) {
+            log.warn("No data found for OLT device {}", port.deviceId());
+            return;
+        }
+
+        VlanId subscriberVlan = subscribers.remove(port);
+
+        if (subscriberVlan == null) {
+            log.warn("Unknown subscriber at location {}", port);
+            return;
+        }
+
+        unprovisionSubscriber(olt.deviceId(), olt.uplink(), port.port(), subscriberVlan,
+                              olt.vlan(), olt.defaultVlan());
+
+    }
+
+    @Override
+    public Collection<Map.Entry<ConnectPoint, VlanId>> getSubscribers() {
+        return subscribers.entrySet();
+    }
+
+    @Override
+    public Map<DeviceId, AccessDeviceData> fetchOlts() {
+        return Maps.newHashMap(oltData);
+    }
+
+    private void unprovisionSubscriber(DeviceId deviceId, PortNumber uplink,
+                                       PortNumber subscriberPort, VlanId subscriberVlan,
+                                       VlanId deviceVlan, Optional<VlanId> defaultVlan) {
+
+        CompletableFuture<ObjectiveError> downFuture = new CompletableFuture();
+        CompletableFuture<ObjectiveError> upFuture = new CompletableFuture();
+
+        ForwardingObjective.Builder upFwd = upBuilder(uplink, subscriberPort,
+                                                      subscriberVlan, deviceVlan,
+                                                      defaultVlan);
+        ForwardingObjective.Builder downFwd = downBuilder(uplink, subscriberPort,
+                                                          subscriberVlan, deviceVlan,
+                                                          defaultVlan);
+
+
+        flowObjectiveService.forward(deviceId, upFwd.remove(new ObjectiveContext() {
+            @Override
+            public void onSuccess(Objective objective) {
+                upFuture.complete(null);
+            }
+
+            @Override
+            public void onError(Objective objective, ObjectiveError error) {
+                upFuture.complete(error);
+            }
+        }));
+
+        flowObjectiveService.forward(deviceId, downFwd.remove(new ObjectiveContext() {
+            @Override
+            public void onSuccess(Objective objective) {
+                downFuture.complete(null);
+            }
+
+            @Override
+            public void onError(Objective objective, ObjectiveError error) {
+                downFuture.complete(error);
+            }
+        }));
+
+        upFuture.thenAcceptBothAsync(downFuture, (upStatus, downStatus) -> {
+            if (upStatus == null && downStatus == null) {
+                post(new AccessDeviceEvent(AccessDeviceEvent.Type.SUBSCRIBER_UNREGISTERED,
+                                           deviceId,
+                                           deviceVlan,
+                                           subscriberVlan));
+            } else if (downStatus != null) {
+                log.error("Subscriber with vlan {} on device {} " +
+                                  "on port {} failed downstream uninstallation: {}",
+                          subscriberVlan, deviceId, subscriberPort, downStatus);
+            } else if (upStatus != null) {
+                log.error("Subscriber with vlan {} on device {} " +
+                                  "on port {} failed upstream uninstallation: {}",
+                          subscriberVlan, deviceId, subscriberPort, upStatus);
+            }
+        }, oltInstallers);
+
+    }
+
+    private void provisionVlans(DeviceId deviceId, PortNumber uplinkPort,
+                                PortNumber subscriberPort,
+                                VlanId subscriberVlan, VlanId deviceVlan,
+                                Optional<VlanId> defaultVlan) {
+
+        CompletableFuture<ObjectiveError> downFuture = new CompletableFuture();
+        CompletableFuture<ObjectiveError> upFuture = new CompletableFuture();
+
+        ForwardingObjective.Builder upFwd = upBuilder(uplinkPort, subscriberPort,
+                                                      subscriberVlan, deviceVlan,
+                                                      defaultVlan);
+
+
+        ForwardingObjective.Builder downFwd = downBuilder(uplinkPort, subscriberPort,
+                                                          subscriberVlan, deviceVlan,
+                                                          defaultVlan);
+
+        ConnectPoint cp = new ConnectPoint(deviceId, subscriberPort);
+        subscribers.put(cp, subscriberVlan);
+
+        flowObjectiveService.forward(deviceId, upFwd.add(new ObjectiveContext() {
+            @Override
+            public void onSuccess(Objective objective) {
+                upFuture.complete(null);
+            }
+
+            @Override
+            public void onError(Objective objective, ObjectiveError error) {
+                upFuture.complete(error);
+            }
+        }));
+
+        flowObjectiveService.forward(deviceId, downFwd.add(new ObjectiveContext() {
+            @Override
+            public void onSuccess(Objective objective) {
+                downFuture.complete(null);
+            }
+
+            @Override
+            public void onError(Objective objective, ObjectiveError error) {
+                downFuture.complete(error);
+            }
+        }));
+
+        upFuture.thenAcceptBothAsync(downFuture, (upStatus, downStatus) -> {
+            if (upStatus == null && downStatus == null) {
+                post(new AccessDeviceEvent(AccessDeviceEvent.Type.SUBSCRIBER_REGISTERED,
+                                           deviceId,
+                                           deviceVlan,
+                                           subscriberVlan));
+
+            } else if (downStatus != null) {
+                log.error("Subscriber with vlan {} on device {} " +
+                                  "on port {} failed downstream installation: {}",
+                          subscriberVlan, deviceId, subscriberPort, downStatus);
+            } else if (upStatus != null) {
+                log.error("Subscriber with vlan {} on device {} " +
+                                  "on port {} failed upstream installation: {}",
+                          subscriberVlan, deviceId, subscriberPort, upStatus);
+            }
+        }, oltInstallers);
+
+    }
+
+    private ForwardingObjective.Builder downBuilder(PortNumber uplinkPort,
+                                                    PortNumber subscriberPort,
+                                                    VlanId subscriberVlan,
+                                                    VlanId deviceVlan,
+                                                    Optional<VlanId> defaultVlan) {
+        TrafficSelector downstream = DefaultTrafficSelector.builder()
+                .matchVlanId(deviceVlan)
+                .matchInPort(uplinkPort)
+                .matchInnerVlanId(subscriberVlan)
+                .build();
+
+        TrafficTreatment downstreamTreatment = DefaultTrafficTreatment.builder()
+                .popVlan()
+                .setVlanId(defaultVlan.orElse(VlanId.vlanId((short) this.defaultVlan)))
+                .setOutput(subscriberPort)
+                .build();
+
+        return DefaultForwardingObjective.builder()
+                .withFlag(ForwardingObjective.Flag.VERSATILE)
+                .withPriority(1000)
+                .makePermanent()
+                .withSelector(downstream)
+                .fromApp(appId)
+                .withTreatment(downstreamTreatment);
+    }
+
+    private ForwardingObjective.Builder upBuilder(PortNumber uplinkPort,
+                                                  PortNumber subscriberPort,
+                                                  VlanId subscriberVlan,
+                                                  VlanId deviceVlan,
+                                                  Optional<VlanId> defaultVlan) {
+        TrafficSelector upstream = DefaultTrafficSelector.builder()
+                .matchVlanId(defaultVlan.orElse(VlanId.vlanId((short) this.defaultVlan)))
+                .matchInPort(subscriberPort)
+                .build();
+
+
+        TrafficTreatment upstreamTreatment = DefaultTrafficTreatment.builder()
+                .pushVlan()
+                .setVlanId(subscriberVlan)
+                .pushVlan()
+                .setVlanId(deviceVlan)
+                .setOutput(uplinkPort)
+                .build();
+
+        return DefaultForwardingObjective.builder()
+                .withFlag(ForwardingObjective.Flag.VERSATILE)
+                .withPriority(1000)
+                .makePermanent()
+                .withSelector(upstream)
+                .fromApp(appId)
+                .withTreatment(upstreamTreatment);
+    }
+
+    private void processFilteringObjectives(DeviceId devId, PortNumber port, boolean install) {
+        if (!mastershipService.isLocalMaster(devId)) {
+            return;
+        }
+        DefaultFilteringObjective.Builder builder = DefaultFilteringObjective.builder();
+
+        FilteringObjective eapol = (install ? builder.permit() : builder.deny())
+                .withKey(Criteria.matchInPort(port))
+                .addCondition(Criteria.matchEthType(EthType.EtherType.EAPOL.ethType()))
+                .withMeta(DefaultTrafficTreatment.builder()
+                                  .setOutput(PortNumber.CONTROLLER).build())
+                .fromApp(appId)
+                .withPriority(1000)
+                .add(new ObjectiveContext() {
+                    @Override
+                    public void onSuccess(Objective objective) {
+                        log.info("Eapol filter for {} on {} installed.",
+                                 devId, port);
+                    }
+
+                    @Override
+                    public void onError(Objective objective, ObjectiveError error) {
+                        log.info("Eapol filter for {} on {} failed because {}",
+                                 devId, port, error);
+                    }
+                });
+
+        flowObjectiveService.filter(devId, eapol);
+
+    }
+
+    private class InternalDeviceListener implements DeviceListener {
+        @Override
+        public void event(DeviceEvent event) {
+            DeviceId devId = event.subject().id();
+            if (!oltData.containsKey(devId)) {
+                return;
+            }
+            switch (event.type()) {
+                //TODO: Port handling and bookkeeping should be improved once
+                // olt firmware handles correct behaviour.
+                case PORT_ADDED:
+                    if (!oltData.get(devId).uplink().equals(event.port().number()) &&
+                            event.port().isEnabled()) {
+                        processFilteringObjectives(devId, event.port().number(), true);
+                    }
+                    break;
+                case PORT_REMOVED:
+                    AccessDeviceData olt = oltData.get(devId);
+                    VlanId vlan = subscribers.get(new ConnectPoint(devId,
+                                                                   event.port().number()));
+                    unprovisionSubscriber(devId, olt.uplink(),
+                                          event.port().number(),
+                                          vlan, olt.vlan(), olt.defaultVlan());
+                    if (!oltData.get(devId).uplink().equals(event.port().number()) &&
+                            event.port().isEnabled()) {
+                        processFilteringObjectives(devId, event.port().number(), false);
+                    }
+                    break;
+                case PORT_UPDATED:
+                    if (oltData.get(devId).uplink().equals(event.port().number())) {
+                        break;
+                    }
+                    if (event.port().isEnabled()) {
+                        processFilteringObjectives(devId, event.port().number(), true);
+                    } else {
+                        processFilteringObjectives(devId, event.port().number(), false);
+                    }
+                    break;
+                case DEVICE_ADDED:
+                    post(new AccessDeviceEvent(
+                            AccessDeviceEvent.Type.DEVICE_CONNECTED, devId,
+                            null, null));
+                    provisionDefaultFlows(devId);
+                    break;
+                case DEVICE_REMOVED:
+                    post(new AccessDeviceEvent(
+                            AccessDeviceEvent.Type.DEVICE_DISCONNECTED, devId,
+                            null, null));
+                    break;
+                case DEVICE_AVAILABILITY_CHANGED:
+                    if (deviceService.isAvailable(devId)) {
+                        post(new AccessDeviceEvent(
+                                AccessDeviceEvent.Type.DEVICE_CONNECTED, devId,
+                                null, null));
+                    } else {
+                        post(new AccessDeviceEvent(
+                                AccessDeviceEvent.Type.DEVICE_DISCONNECTED, devId,
+                                null, null));
+                    }
+                    break;
+                case DEVICE_UPDATED:
+                case DEVICE_SUSPENDED:
+                case PORT_STATS_UPDATED:
+                default:
+                    return;
+            }
+        }
+    }
+
+    private class InternalNetworkConfigListener implements NetworkConfigListener {
+        @Override
+        public void event(NetworkConfigEvent event) {
+            switch (event.type()) {
+
+                case CONFIG_ADDED:
+                case CONFIG_UPDATED:
+
+                    AccessDeviceConfig config =
+                            networkConfig.getConfig((DeviceId) event.subject(), CONFIG_CLASS);
+                    if (config != null) {
+                        oltData.put(config.getOlt().deviceId(), config.getOlt());
+                        provisionDefaultFlows((DeviceId) event.subject());
+                    }
+
+                    break;
+                case CONFIG_REGISTERED:
+                case CONFIG_UNREGISTERED:
+                    break;
+                case CONFIG_REMOVED:
+                    oltData.remove(event.subject());
+                default:
+                    break;
+            }
+        }
+
+        @Override
+        public boolean isRelevant(NetworkConfigEvent event) {
+            return event.configClass().equals(CONFIG_CLASS);
+        }
+    }
+
+    private void provisionDefaultFlows(DeviceId deviceId) {
+        if (!mastershipService.isLocalMaster(deviceId)) {
+            return;
+        }
+        List<Port> ports = deviceService.getPorts(deviceId);
+
+        ports.stream()
+                .filter(p -> !oltData.get(p.element().id()).uplink().equals(p.number()))
+                .filter(p -> p.isEnabled())
+                .forEach(p -> processFilteringObjectives((DeviceId) p.element().id(),
+                                                         p.number(), true));
+
+    }
+
+}