diff --git a/providers/lldp/src/main/java/org/onlab/onos/provider/lldp/impl/LinkDiscovery.java b/providers/lldp/src/main/java/org/onlab/onos/provider/lldp/impl/LinkDiscovery.java
index 4282199..3862437 100644
--- a/providers/lldp/src/main/java/org/onlab/onos/provider/lldp/impl/LinkDiscovery.java
+++ b/providers/lldp/src/main/java/org/onlab/onos/provider/lldp/impl/LinkDiscovery.java
@@ -83,6 +83,7 @@
     private final PacketService pktService;
     private final MastershipService mastershipService;
     private Timeout timeout;
+    private boolean isStopped;
 
     /**
      * Instantiates discovery manager for the given physical switch. Creates a
@@ -289,11 +290,13 @@
 
     public void stop() {
         timeout.cancel();
+        isStopped = true;
     }
 
     public void start() {
         timeout = Timer.getTimer().newTimeout(this, 0,
                                               TimeUnit.MILLISECONDS);
+        isStopped = false;
     }
 
     /**
@@ -352,4 +355,15 @@
        }
     }
 
+    public boolean containsPort(Long portNumber) {
+        if (slowPorts.contains(portNumber) || fastPorts.contains(portNumber)) {
+            return true;
+        }
+        return false;
+    }
+
+    public boolean isStopped() {
+        return isStopped;
+    }
+
 }
diff --git a/providers/lldp/src/test/java/org/onlab/onos/provider/lldp/impl/LLDPLinkProviderTest.java b/providers/lldp/src/test/java/org/onlab/onos/provider/lldp/impl/LLDPLinkProviderTest.java
new file mode 100644
index 0000000..ded5e67
--- /dev/null
+++ b/providers/lldp/src/test/java/org/onlab/onos/provider/lldp/impl/LLDPLinkProviderTest.java
@@ -0,0 +1,488 @@
+package org.onlab.onos.provider.lldp.impl;
+
+
+import com.google.common.collect.ArrayListMultimap;
+import com.google.common.collect.Lists;
+import com.google.common.collect.Maps;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.onlab.onos.cluster.NodeId;
+import org.onlab.onos.mastership.MastershipListener;
+import org.onlab.onos.mastership.MastershipService;
+import org.onlab.onos.mastership.MastershipTermService;
+import org.onlab.onos.net.ConnectPoint;
+import org.onlab.onos.net.DefaultDevice;
+import org.onlab.onos.net.DefaultPort;
+import org.onlab.onos.net.Device;
+import org.onlab.onos.net.DeviceId;
+import org.onlab.onos.net.MastershipRole;
+import org.onlab.onos.net.Port;
+import org.onlab.onos.net.PortNumber;
+import org.onlab.onos.net.device.DeviceEvent;
+import org.onlab.onos.net.device.DeviceListener;
+import org.onlab.onos.net.device.DeviceService;
+import org.onlab.onos.net.flow.TrafficTreatment;
+import org.onlab.onos.net.link.LinkDescription;
+import org.onlab.onos.net.link.LinkProvider;
+import org.onlab.onos.net.link.LinkProviderRegistry;
+import org.onlab.onos.net.link.LinkProviderService;
+import org.onlab.onos.net.packet.DefaultInboundPacket;
+import org.onlab.onos.net.packet.InboundPacket;
+import org.onlab.onos.net.packet.OutboundPacket;
+import org.onlab.onos.net.packet.PacketContext;
+import org.onlab.onos.net.packet.PacketProcessor;
+import org.onlab.onos.net.packet.PacketService;
+import org.onlab.onos.net.provider.AbstractProviderService;
+import org.onlab.onos.net.provider.ProviderId;
+
+import org.onlab.packet.ChassisId;
+import org.onlab.packet.Ethernet;
+
+import org.onlab.packet.ONOSLLDP;
+
+import java.nio.ByteBuffer;
+import java.util.HashMap;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import static org.junit.Assert.*;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+public class LLDPLinkProviderTest {
+
+    private static final DeviceId DID1 = DeviceId.deviceId("of:0000000000000001");
+    private static final DeviceId DID2 = DeviceId.deviceId("of:0000000000000002");
+
+    private static Port pd1;
+    private static Port pd2;
+    private static Port pd3;
+    private static Port pd4;
+
+    private final LLDPLinkProvider provider = new LLDPLinkProvider();
+    private final TestLinkRegistry linkService = new TestLinkRegistry();
+    private final TestPacketService packetService = new TestPacketService();
+    private final TestDeviceService deviceService = new TestDeviceService();
+    private final TestMasterShipService masterService = new TestMasterShipService();
+
+    private TestLinkProviderService providerService;
+
+    private PacketProcessor testProcessor;
+    private DeviceListener deviceListener;
+
+    @Before
+    public void setUp() {
+
+        provider.deviceService = deviceService;
+        provider.packetSevice = packetService;
+        provider.providerRegistry = linkService;
+        provider.masterService = masterService;
+
+
+        provider.activate();
+    }
+
+    @Test
+    public void basics() {
+        assertNotNull("registration expected", providerService);
+        assertEquals("incorrect provider", provider, providerService.provider());
+    }
+
+    @Test
+    public void switchAdd() {
+        DeviceEvent de = deviceEvent(DeviceEvent.Type.DEVICE_ADDED, DID1);
+        deviceListener.event(de);
+
+        assertFalse("Device not added", provider.discoverers.isEmpty());
+    }
+
+    @Test
+    public void switchRemove() {
+        deviceListener.event(deviceEvent(DeviceEvent.Type.DEVICE_ADDED, DID1));
+        deviceListener.event(deviceEvent(DeviceEvent.Type.DEVICE_REMOVED, DID1));
+
+        assertTrue("Discoverer is not gone", provider.discoverers.get(DID1).isStopped());
+        assertTrue("Device is not gone.", vanishedDpid(DID1));
+    }
+
+    @Test
+    public void portUp() {
+        deviceListener.event(deviceEvent(DeviceEvent.Type.DEVICE_ADDED, DID1));
+        deviceListener.event(portEvent(DeviceEvent.Type.PORT_ADDED, DID1, port(DID1, 3, true)));
+
+        assertTrue("Port not added to discoverer",
+                   provider.discoverers.get(DID1).containsPort((long) 3));
+    }
+
+    @Test
+    public void portDown() {
+
+        deviceListener.event(deviceEvent(DeviceEvent.Type.DEVICE_ADDED, DID1));
+        deviceListener.event(portEvent(DeviceEvent.Type.PORT_ADDED, DID1, port(DID1, 1, false)));
+
+
+
+        assertFalse("Port added to discoverer",
+                    provider.discoverers.get(DID1).containsPort((long) 1));
+        assertTrue("Port is not gone.", vanishedPort((long) 1));
+    }
+
+    @Test
+    public void portUnknown() {
+        deviceListener.event(deviceEvent(DeviceEvent.Type.DEVICE_ADDED, DID1));
+        deviceListener.event(portEvent(DeviceEvent.Type.PORT_ADDED, DID2, port(DID2, 1, false)));
+
+
+        assertNull("DPID exists",
+                   provider.discoverers.get(DID2));
+    }
+
+    @Test
+    public void unknownPktCtx() {
+
+        PacketContext pktCtx = new TestPacketContext(deviceService.getDevice(DID2));
+
+        testProcessor.process(pktCtx);
+        assertFalse("Context should still be free", pktCtx.isHandled());
+    }
+
+    @Test
+    public void knownPktCtx() {
+        deviceListener.event(deviceEvent(DeviceEvent.Type.DEVICE_ADDED, DID1));
+        deviceListener.event(deviceEvent(DeviceEvent.Type.DEVICE_ADDED, DID2));
+        PacketContext pktCtx = new TestPacketContext(deviceService.getDevice(DID2));
+
+
+        testProcessor.process(pktCtx);
+
+        assertTrue("Link not detected", detectedLink(DID1, DID2));
+
+    }
+
+
+    @After
+    public void tearDown() {
+        provider.deactivate();
+        provider.providerRegistry = null;
+        provider.deviceService = null;
+        provider.packetSevice = null;
+    }
+
+    private DeviceEvent deviceEvent(DeviceEvent.Type type, DeviceId did) {
+        return new DeviceEvent(type, deviceService.getDevice(did));
+
+    }
+
+    private DeviceEvent portEvent(DeviceEvent.Type type, DeviceId did, PortNumber port) {
+        return new  DeviceEvent(type, deviceService.getDevice(did),
+                                deviceService.getPort(did, port));
+    }
+
+    private DeviceEvent portEvent(DeviceEvent.Type type, DeviceId did, Port port) {
+        return new  DeviceEvent(type, deviceService.getDevice(did), port);
+    }
+
+    private Port port(DeviceId did, long port, boolean enabled) {
+        return new DefaultPort(deviceService.getDevice(did),
+                               PortNumber.portNumber(port), enabled);
+    }
+
+
+    private boolean vanishedDpid(DeviceId... dids) {
+        for (int i = 0; i < dids.length; i++) {
+            if (!providerService.vanishedDpid.contains(dids[i])) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    private boolean vanishedPort(Long... ports) {
+        for (int i = 0; i < ports.length; i++) {
+            if (!providerService.vanishedPort.contains(ports[i])) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    private boolean detectedLink(DeviceId src, DeviceId dst) {
+        for (DeviceId key : providerService.discoveredLinks.keySet()) {
+            if (key.equals(src)) {
+                return providerService.discoveredLinks.get(src).equals(dst);
+            }
+        }
+        return false;
+    }
+
+
+    private class TestLinkRegistry implements LinkProviderRegistry {
+
+        @Override
+        public LinkProviderService register(LinkProvider provider) {
+            providerService = new TestLinkProviderService(provider);
+            return providerService;
+        }
+
+        @Override
+        public void unregister(LinkProvider provider) {
+        }
+
+        @Override
+        public Set<ProviderId> getProviders() {
+            return null;
+        }
+
+    }
+
+    private class TestLinkProviderService
+            extends AbstractProviderService<LinkProvider>
+            implements LinkProviderService {
+
+        List<DeviceId> vanishedDpid = Lists.newLinkedList();
+        List<Long> vanishedPort = Lists.newLinkedList();
+        Map<DeviceId, DeviceId> discoveredLinks = Maps.newHashMap();
+
+        protected TestLinkProviderService(LinkProvider provider) {
+            super(provider);
+        }
+
+        @Override
+        public void linkDetected(LinkDescription linkDescription) {
+            DeviceId sDid = linkDescription.src().deviceId();
+            DeviceId dDid = linkDescription.dst().deviceId();
+            discoveredLinks.put(sDid, dDid);
+        }
+
+        @Override
+        public void linkVanished(LinkDescription linkDescription) {
+            // TODO Auto-generated method stub
+
+        }
+
+        @Override
+        public void linksVanished(ConnectPoint connectPoint) {
+            vanishedPort.add(connectPoint.port().toLong());
+
+        }
+
+        @Override
+        public void linksVanished(DeviceId deviceId) {
+            vanishedDpid.add(deviceId);
+        }
+
+
+    }
+
+
+
+    private class TestPacketContext implements PacketContext {
+
+        protected Device device;
+        protected boolean blocked = false;
+
+        public TestPacketContext(Device dev) {
+            device = dev;
+        }
+
+        @Override
+        public long time() {
+            return 0;
+        }
+
+        @Override
+        public InboundPacket inPacket() {
+            ONOSLLDP lldp = new ONOSLLDP();
+            lldp.setChassisId(device.chassisId());
+            lldp.setPortId((int) pd1.number().toLong());
+            lldp.setDevice(deviceService.getDevice(DID1).id().toString());
+
+
+            Ethernet ethPacket = new Ethernet();
+            ethPacket.setEtherType(Ethernet.TYPE_LLDP);
+            ethPacket.setDestinationMACAddress(ONOSLLDP.LLDP_NICIRA);
+            ethPacket.setPayload(lldp);
+            ethPacket.setPad(true);
+
+
+
+            ethPacket.setSourceMACAddress("DE:AD:BE:EF:BA:11");
+
+            ConnectPoint cp = new ConnectPoint(device.id(), pd3.number());
+
+            return new DefaultInboundPacket(cp, ethPacket,
+                                            ByteBuffer.wrap(ethPacket.serialize()));
+
+        }
+
+        @Override
+        public OutboundPacket outPacket() {
+            return null;
+        }
+
+        @Override
+        public TrafficTreatment.Builder treatmentBuilder() {
+            return null;
+        }
+
+        @Override
+        public void send() {
+
+        }
+
+        @Override
+        public boolean block() {
+            blocked = true;
+            return blocked;
+        }
+
+        @Override
+        public boolean isHandled() {
+            return blocked;
+        }
+
+    }
+
+    private class TestPacketService implements PacketService {
+
+        @Override
+        public void addProcessor(PacketProcessor processor, int priority) {
+            testProcessor = processor;
+        }
+
+        @Override
+        public void removeProcessor(PacketProcessor processor) {
+
+        }
+
+        @Override
+        public void emit(OutboundPacket packet) {
+
+        }
+    }
+
+    private class TestDeviceService implements DeviceService {
+
+        private Map<DeviceId, Device> devices = new HashMap<>();
+        private final ArrayListMultimap<DeviceId, Port> ports =
+                ArrayListMultimap.create();
+
+        public TestDeviceService() {
+            Device d1 = new DefaultDevice(ProviderId.NONE, DID1, Device.Type.SWITCH,
+                                          "TESTMF", "TESTHW", "TESTSW", "TESTSN", new ChassisId());
+            Device d2 = new DefaultDevice(ProviderId.NONE, DID2, Device.Type.SWITCH,
+                                          "TESTMF", "TESTHW", "TESTSW", "TESTSN", new ChassisId());
+            devices.put(DID1, d1);
+            devices.put(DID2, d2);
+
+            pd1 = new DefaultPort(d1, PortNumber.portNumber(1), true);
+            pd2 = new DefaultPort(d1, PortNumber.portNumber(2), true);
+            pd3 = new DefaultPort(d2, PortNumber.portNumber(1), true);
+            pd4 = new DefaultPort(d2, PortNumber.portNumber(2), true);
+
+            ports.putAll(DID1, Lists.newArrayList(pd1, pd2));
+            ports.putAll(DID2, Lists.newArrayList(pd3, pd4));
+
+
+        }
+
+        @Override
+        public int getDeviceCount() {
+            return devices.values().size();
+        }
+
+        @Override
+        public Iterable<Device> getDevices() {
+            return devices.values();
+        }
+
+        @Override
+        public Device getDevice(DeviceId deviceId) {
+            return devices.get(deviceId);
+        }
+
+        @Override
+        public MastershipRole getRole(DeviceId deviceId) {
+            return MastershipRole.MASTER;
+        }
+
+        @Override
+        public List<Port> getPorts(DeviceId deviceId) {
+            return ports.get(deviceId);
+        }
+
+        @Override
+        public Port getPort(DeviceId deviceId, PortNumber portNumber) {
+            for (Port p : ports.get(deviceId)) {
+                if (p.number().equals(portNumber)) {
+                    return p;
+                }
+            }
+            return null;
+        }
+
+        @Override
+        public boolean isAvailable(DeviceId deviceId) {
+            return true;
+        }
+
+        @Override
+        public void addListener(DeviceListener listener) {
+            deviceListener = listener;
+
+        }
+
+        @Override
+        public void removeListener(DeviceListener listener) {
+
+        }
+    }
+
+    private final class TestMasterShipService implements MastershipService {
+
+        @Override
+        public MastershipRole getLocalRole(DeviceId deviceId) {
+            return MastershipRole.MASTER;
+        }
+
+        @Override
+        public MastershipRole requestRoleFor(DeviceId deviceId) {
+            return null;
+        }
+
+        @Override
+        public void relinquishMastership(DeviceId deviceId) {
+
+        }
+
+        @Override
+        public NodeId getMasterFor(DeviceId deviceId) {
+            return null;
+        }
+
+        @Override
+        public Set<DeviceId> getDevicesOf(NodeId nodeId) {
+            return null;
+        }
+
+        @Override
+        public MastershipTermService requestTermService() {
+            return null;
+        }
+
+        @Override
+        public void addListener(MastershipListener listener) {
+
+        }
+
+        @Override
+        public void removeListener(MastershipListener listener) {
+
+        }
+    }
+
+
+}