diff --git a/providers/of/link/src/main/java/org/onlab/onos/provider/of/link/impl/LinkDiscovery.java b/providers/of/link/src/main/java/org/onlab/onos/provider/of/link/impl/LinkDiscovery.java
new file mode 100644
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--- /dev/null
+++ b/providers/of/link/src/main/java/org/onlab/onos/provider/of/link/impl/LinkDiscovery.java
@@ -0,0 +1,395 @@
+/*******************************************************************************
+ * Copyright 2014 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.onlab.onos.provider.of.link.impl;
+
+import static org.slf4j.LoggerFactory.getLogger;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.jboss.netty.util.Timeout;
+import org.jboss.netty.util.TimerTask;
+import org.onlab.onos.net.ConnectPoint;
+import org.onlab.onos.net.DeviceId;
+import org.onlab.onos.net.Link.Type;
+import org.onlab.onos.net.PortNumber;
+import org.onlab.onos.net.link.DefaultLinkDescription;
+import org.onlab.onos.net.link.LinkDescription;
+import org.onlab.onos.net.link.LinkProviderService;
+import org.onlab.onos.of.controller.Dpid;
+import org.onlab.onos.of.controller.OpenFlowController;
+import org.onlab.onos.of.controller.OpenFlowSwitch;
+import org.onlab.packet.Ethernet;
+import org.onlab.packet.ONLabLddp;
+import org.onlab.packet.ONLabLddp.DPIDandPort;
+import org.onlab.timer.Timer;
+import org.projectfloodlight.openflow.protocol.OFFactory;
+import org.projectfloodlight.openflow.protocol.OFMessage;
+import org.projectfloodlight.openflow.protocol.OFPacketOut;
+import org.projectfloodlight.openflow.protocol.OFPortDesc;
+import org.projectfloodlight.openflow.protocol.action.OFAction;
+import org.projectfloodlight.openflow.protocol.action.OFActionOutput;
+import org.projectfloodlight.openflow.types.OFBufferId;
+import org.projectfloodlight.openflow.types.OFPort;
+import org.slf4j.Logger;
+
+
+
+/**
+ * Run discovery process from a physical switch. Ports are initially labeled as
+ * slow ports. When an LLDP is successfully received, label the remote port as
+ * fast. Every probeRate milliseconds, loop over all fast ports and send an
+ * LLDP, send an LLDP for a single slow port. Based on FlowVisor topology
+ * discovery implementation.
+ *
+ * TODO: add 'fast discovery' mode: drop LLDPs in destination switch but listen
+ * for flow_removed messages
+ */
+public class LinkDiscovery implements TimerTask {
+
+    private final OpenFlowSwitch sw;
+    // send 1 probe every probeRate milliseconds
+    private final long probeRate;
+    private final Set<Integer> slowPorts;
+    private final Set<Integer> fastPorts;
+    // number of unacknowledged probes per port
+    private final Map<Integer, AtomicInteger> portProbeCount;
+    // number of probes to send before link is removed
+    private static final short MAX_PROBE_COUNT = 3;
+    private Iterator<Integer> slowIterator;
+    private final OFFactory ofFactory;
+    private final Logger log = getLogger(getClass());
+    private final ONLabLddp lldpPacket;
+    private final Ethernet ethPacket;
+    private Ethernet bddpEth;
+    private final boolean useBDDP;
+    private final OpenFlowController ctrl;
+    private final LinkProviderService linkProvider;
+
+    /**
+     * Instantiates discovery manager for the given physical switch. Creates a
+     * generic LLDP packet that will be customized for the port it is sent out on.
+     * Starts the the timer for the discovery process.
+     *
+     * @param sw the physical switch
+     * @param useBDDP flag to also use BDDP for discovery
+     */
+    public LinkDiscovery(final OpenFlowSwitch sw,
+            OpenFlowController ctrl, LinkProviderService providerService, Boolean... useBDDP) {
+        this.sw = sw;
+        this.ofFactory = sw.factory();
+        this.ctrl = ctrl;
+        this.probeRate = 1000;
+        this.linkProvider = providerService;
+        this.slowPorts = Collections.synchronizedSet(new HashSet<Integer>());
+        this.fastPorts = Collections.synchronizedSet(new HashSet<Integer>());
+        this.portProbeCount = new HashMap<Integer, AtomicInteger>();
+        this.lldpPacket = new ONLabLddp();
+        this.lldpPacket.setSwitch(this.sw.getId());
+        this.ethPacket = new Ethernet();
+        this.ethPacket.setEtherType(Ethernet.TYPE_LLDP);
+        this.ethPacket.setDestinationMACAddress(ONLabLddp.LLDP_NICIRA);
+        this.ethPacket.setPayload(this.lldpPacket);
+        this.ethPacket.setPad(true);
+        this.useBDDP = useBDDP.length > 0 ? useBDDP[0] : false;
+        if (this.useBDDP) {
+            this.bddpEth = new Ethernet();
+            this.bddpEth.setPayload(this.lldpPacket);
+            this.bddpEth.setEtherType(Ethernet.TYPE_BSN);
+            this.bddpEth.setDestinationMACAddress(ONLabLddp.BDDP_MULTICAST);
+            this.bddpEth.setPad(true);
+            log.info("Using BDDP to discover network");
+        }
+        for (OFPortDesc port : sw.getPorts()) {
+            if (port.getPortNo() != OFPort.LOCAL) {
+                addPort(port);
+            }
+        }
+        Timer.getTimer().newTimeout(this, this.probeRate,
+                TimeUnit.MILLISECONDS);
+        this.log.debug("Started discovery manager for switch {}",
+                sw.getId());
+
+    }
+
+    /**
+     * Add physical port port to discovery process.
+     * Send out initial LLDP and label it as slow port.
+     *
+     * @param port the port
+     */
+    public void addPort(final OFPortDesc port) {
+        // Ignore ports that are not on this switch, or already booted. */
+
+        synchronized (this) {
+            this.log.debug("sending init probe to port {}",
+                    port.getPortNo().getPortNumber());
+            OFPacketOut pkt;
+
+            pkt = this.createLLDPPacketOut(port);
+            this.sw.sendMsg(pkt);
+            if (useBDDP) {
+                OFPacketOut bpkt = this.createBDDPPacketOut(port);
+                this.sw.sendMsg(bpkt);
+            }
+
+            this.slowPorts.add(port.getPortNo().getPortNumber());
+            this.slowIterator = this.slowPorts.iterator();
+        }
+
+    }
+
+    /**
+     * Removes physical port from discovery process.
+     *
+     * @param port the port
+     */
+    public void removePort(final OFPort port) {
+        // Ignore ports that are not on this switch
+
+        int portnum = port.getPortNumber();
+        synchronized (this) {
+            if (this.slowPorts.contains(portnum)) {
+                this.slowPorts.remove(portnum);
+                this.slowIterator = this.slowPorts.iterator();
+
+            } else if (this.fastPorts.contains(portnum)) {
+                this.fastPorts.remove(portnum);
+                this.portProbeCount.remove(portnum);
+                // no iterator to update
+            } else {
+                this.log.warn(
+                        "tried to dynamically remove non-existing port {}",
+                        portnum);
+            }
+        }
+
+    }
+
+    /**
+     * Method called by remote port to acknowledge receipt of LLDP sent by
+     * this port. If slow port, updates label to fast. If fast port, decrements
+     * number of unacknowledged probes.
+     *
+     * @param port the port
+     */
+    public void ackProbe(final Integer port) {
+        final int portNumber = port;
+        synchronized (this) {
+            if (this.slowPorts.contains(portNumber)) {
+                this.log.debug("Setting slow port to fast: {}:{}",
+                        this.sw.getId(), portNumber);
+                this.slowPorts.remove(portNumber);
+                this.slowIterator = this.slowPorts.iterator();
+                this.fastPorts.add(portNumber);
+                this.portProbeCount.put(portNumber, new AtomicInteger(0));
+            } else {
+                if (this.fastPorts.contains(portNumber)) {
+                    this.portProbeCount.get(portNumber).set(0);
+                } else {
+                    this.log.debug(
+                            "Got ackProbe for non-existing port: {}",
+                            portNumber);
+                }
+            }
+        }
+    }
+
+    /**
+     * Creates packet_out LLDP for specified output port.
+     *
+     * @param port the port
+     * @return Packet_out message with LLDP data
+     * @throws PortMappingException
+     */
+    private OFPacketOut createLLDPPacketOut(final OFPortDesc port) {
+        OFPacketOut.Builder packetOut = this.ofFactory.buildPacketOut();
+        packetOut.setBufferId(OFBufferId.NO_BUFFER);
+        OFAction act = this.ofFactory.actions().buildOutput()
+                .setPort(port.getPortNo()).build();
+        packetOut.setActions(Collections.singletonList(act));
+        this.lldpPacket.setPort(port.getPortNo().getPortNumber());
+        this.ethPacket.setSourceMACAddress(port.getHwAddr().getBytes());
+
+        final byte[] lldp = this.ethPacket.serialize();
+        packetOut.setData(lldp);
+        return packetOut.build();
+    }
+
+    /**
+     * Creates packet_out BDDP for specified output port.
+     *
+     * @param port the port
+     * @return Packet_out message with LLDP data
+     * @throws PortMappingException
+     */
+    private OFPacketOut createBDDPPacketOut(final OFPortDesc port) {
+        OFPacketOut.Builder packetOut = sw.factory().buildPacketOut();
+
+        packetOut.setBufferId(OFBufferId.NO_BUFFER);
+
+        OFActionOutput.Builder act = sw.factory().actions().buildOutput()
+                .setPort(port.getPortNo());
+        OFAction out = act.build();
+        packetOut.setActions(Collections.singletonList(out));
+        this.lldpPacket.setPort(port.getPortNo().getPortNumber());
+        this.bddpEth.setSourceMACAddress(port.getHwAddr().getBytes());
+
+        final byte[] bddp = this.bddpEth.serialize();
+        packetOut.setData(bddp);
+
+        return packetOut.build();
+    }
+
+
+    private void sendMsg(final OFMessage msg) {
+        this.sw.sendMsg(msg);
+    }
+
+    public String getName() {
+        return "LinkDiscovery " + this.sw.getStringId();
+    }
+
+    /*
+     * Handles an incoming LLDP packet. Creates link in topology and sends ACK
+     * to port where LLDP originated.
+     */
+    @SuppressWarnings("rawtypes")
+    public void handleLLDP(final Ethernet eth, Integer inPort) {
+
+        final byte[] pkt = eth.serialize();
+
+        if (ONLabLddp.isOVXLLDP(pkt)) {
+            final Integer dstPort = inPort;
+            final DPIDandPort dp = ONLabLddp.parseLLDP(pkt);
+            final OpenFlowSwitch srcSwitch = ctrl.getSwitch(new Dpid(dp.getDpid()));
+            final Integer srcPort = dp.getPort();
+            if (srcSwitch == null) {
+                return;
+            }
+            this.ackProbe(srcPort);
+            ConnectPoint src = new ConnectPoint(
+                    DeviceId.deviceId("of:" + Long.toHexString(srcSwitch.getId())),
+                    PortNumber.portNumber(srcPort));
+
+            ConnectPoint dst = new ConnectPoint(
+                    DeviceId.deviceId("of:" + Long.toHexString(sw.getId())),
+                    PortNumber.portNumber(dstPort));
+            LinkDescription ld;
+            if (eth.getEtherType() == Ethernet.TYPE_BSN) {
+                ld = new DefaultLinkDescription(src, dst, Type.INDIRECT);
+            } else {
+                ld = new DefaultLinkDescription(src, dst, Type.DIRECT);
+            }
+            linkProvider.linkDetected(ld);
+        } else {
+            this.log.debug("Ignoring unknown LLDP");
+        }
+    }
+
+    private OFPortDesc findPort(List<OFPortDesc> ports, Integer inPort) {
+        for (OFPortDesc p : ports) {
+            if (p.getPortNo().getPortNumber() == inPort) {
+                return p;
+            }
+        }
+        return null;
+    }
+
+    /**
+     * Execute this method every t milliseconds. Loops over all ports
+     * labeled as fast and sends out an LLDP. Send out an LLDP on a single slow
+     * port.
+     *
+     * @param t timeout
+     * @throws Exception
+     */
+    @Override
+    public void run(final Timeout t) {
+        this.log.debug("sending probes");
+        synchronized (this) {
+            final Iterator<Integer> fastIterator = this.fastPorts.iterator();
+            while (fastIterator.hasNext()) {
+                final Integer portNumber = fastIterator.next();
+                final int probeCount = this.portProbeCount.get(portNumber)
+                        .getAndIncrement();
+                OFPortDesc port = findPort(this.sw.getPorts(), portNumber);
+                if (probeCount < LinkDiscovery.MAX_PROBE_COUNT) {
+                    this.log.debug("sending fast probe to port");
+
+                    OFPacketOut pkt = this.createLLDPPacketOut(port);
+                    this.sendMsg(pkt);
+                    if (useBDDP) {
+                        OFPacketOut bpkt = this.createBDDPPacketOut(port);
+                        this.sendMsg(bpkt);
+                    }
+                } else {
+                    // Update fast and slow ports
+                    fastIterator.remove();
+                    this.slowPorts.add(portNumber);
+                    this.slowIterator = this.slowPorts.iterator();
+                    this.portProbeCount.remove(portNumber);
+
+                    // Remove link from topology
+                    final OFPortDesc srcPort = port;
+
+                    ConnectPoint cp = new ConnectPoint(
+                            DeviceId.deviceId("of:" + Long.toHexString(sw.getId())),
+                            PortNumber.portNumber(srcPort.getPortNo().getPortNumber()));
+                    linkProvider.linksVanished(cp);
+                }
+            }
+
+            // send a probe for the next slow port
+            if (this.slowPorts.size() > 0) {
+                if (!this.slowIterator.hasNext()) {
+                    this.slowIterator = this.slowPorts.iterator();
+                }
+                if (this.slowIterator.hasNext()) {
+                    final int portNumber = this.slowIterator.next();
+                    this.log.debug("sending slow probe to port {}", portNumber);
+                    OFPortDesc port = findPort(this.sw.getPorts(), portNumber);
+
+                    OFPacketOut pkt = this.createLLDPPacketOut(port);
+                    this.sendMsg(pkt);
+                    if (useBDDP) {
+                        OFPacketOut bpkt = this.createBDDPPacketOut(port);
+                        this.sendMsg(bpkt);
+                    }
+
+                }
+            }
+        }
+
+        // reschedule timer
+        Timer.getTimer().newTimeout(this, this.probeRate,
+                TimeUnit.MILLISECONDS);
+    }
+
+    public void removeAllPorts() {
+        for (OFPortDesc port : sw.getPorts()) {
+            removePort(port.getPortNo());
+        }
+    }
+
+}