Topology Manager to avoid redundant edge updates
[controller.git] / opendaylight / protocol_plugins / openflow / src / main / java / org / opendaylight / controller / protocol_plugin / openflow / internal / DiscoveryService.java
index eab87a4440b356d0f734061505897e3115d87d8e..548bfb1f9fb26eb93ab4ca5bcd456d9bdc4082c3 100644 (file)
@@ -1,4 +1,3 @@
-
 /*
  * Copyright (c) 2013 Cisco Systems, Inc. and others.  All rights reserved.
  *
@@ -9,8 +8,10 @@
 
 package org.opendaylight.controller.protocol_plugin.openflow.internal;
 
+import java.nio.charset.Charset;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
@@ -27,27 +28,22 @@ import org.eclipse.osgi.framework.console.CommandInterpreter;
 import org.eclipse.osgi.framework.console.CommandProvider;
 import org.opendaylight.controller.protocol_plugin.openflow.IDataPacketListen;
 import org.opendaylight.controller.protocol_plugin.openflow.IDataPacketMux;
+import org.opendaylight.controller.protocol_plugin.openflow.IDiscoveryListener;
+import org.opendaylight.controller.protocol_plugin.openflow.IInventoryProvider;
 import org.opendaylight.controller.protocol_plugin.openflow.IInventoryShimExternalListener;
 import org.opendaylight.controller.protocol_plugin.openflow.core.IController;
 import org.opendaylight.controller.protocol_plugin.openflow.core.ISwitch;
-import org.openflow.protocol.OFPhysicalPort;
-import org.osgi.framework.BundleContext;
-import org.osgi.framework.FrameworkUtil;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
+import org.opendaylight.controller.sal.connection.IPluginOutConnectionService;
 import org.opendaylight.controller.sal.core.Config;
 import org.opendaylight.controller.sal.core.ConstructionException;
-import org.opendaylight.controller.sal.core.Edge;
 import org.opendaylight.controller.sal.core.ContainerFlow;
+import org.opendaylight.controller.sal.core.Edge;
 import org.opendaylight.controller.sal.core.IContainerListener;
 import org.opendaylight.controller.sal.core.Node;
 import org.opendaylight.controller.sal.core.NodeConnector;
 import org.opendaylight.controller.sal.core.Property;
 import org.opendaylight.controller.sal.core.State;
 import org.opendaylight.controller.sal.core.UpdateType;
-import org.opendaylight.controller.sal.discovery.IDiscoveryService;
-import org.opendaylight.controller.sal.inventory.IPluginInInventoryService;
 import org.opendaylight.controller.sal.packet.Ethernet;
 import org.opendaylight.controller.sal.packet.LLDP;
 import org.opendaylight.controller.sal.packet.LLDPTLV;
@@ -59,60 +55,88 @@ import org.opendaylight.controller.sal.utils.HexEncode;
 import org.opendaylight.controller.sal.utils.NetUtils;
 import org.opendaylight.controller.sal.utils.NodeConnectorCreator;
 import org.opendaylight.controller.sal.utils.NodeCreator;
+import org.openflow.protocol.OFPhysicalPort;
+import org.osgi.framework.BundleContext;
+import org.osgi.framework.FrameworkUtil;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * The class describes neighbor discovery service for an OpenFlow network.
  */
-public class DiscoveryService implements IInventoryShimExternalListener,
-        IDataPacketListen, IContainerListener, CommandProvider {
-    private static Logger logger = LoggerFactory
-            .getLogger(DiscoveryService.class);
+public class DiscoveryService implements IInventoryShimExternalListener, IDataPacketListen, IContainerListener,
+        CommandProvider {
+    private static Logger logger = LoggerFactory.getLogger(DiscoveryService.class);
     private IController controller = null;
-    private IDiscoveryService discoveryService = null;
-    private IPluginInInventoryService pluginInInventoryService = null;
+    private IDiscoveryListener discoveryListener = null;
+    private IInventoryProvider inventoryProvider = null;
     private IDataPacketMux iDataPacketMux = null;
-
-    private List<NodeConnector> readyListHi = null; // newly added ports go into this list and will be served first
-    private List<NodeConnector> readyListLo = null; // come here after served at least once
-    private List<NodeConnector> waitingList = null; // staging area during quiet period
-    private ConcurrentMap<NodeConnector, Integer> pendingMap = null;// wait for response back
-    private ConcurrentMap<NodeConnector, Edge> edgeMap = null; // openflow edges keyed by head connector
-    private ConcurrentMap<NodeConnector, Integer> agingMap = null; // aging entries keyed by edge port
-    private ConcurrentMap<NodeConnector, Edge> prodMap = null; // production edges keyed by edge port
-
-    private Timer discoveryTimer; // discovery timer
-    private DiscoveryTimerTask discoveryTimerTask; // timer task
-    private long discoveryTimerTick = 1L * 1000; // per tick in msec
+    // High priority list containing newly added ports which will be served first
+    private List<NodeConnector> readyListHi = null;
+    // List containing all the ports which will be served periodically
+    private List<NodeConnector> readyListLo = null;
+    // Staging area during quiet period
+    private List<NodeConnector> stagingList = null;
+    // Wait for next discovery packet. The map contains the time elapsed since
+    // the last received LLDP frame on each node connector
+    private ConcurrentMap<NodeConnector, Integer> holdTime = null;
+    // Allow one more retry for newly added ports. This map contains the time
+    // period elapsed since last discovery pkt transmission on the port.
+    private ConcurrentMap<NodeConnector, Integer> elapsedTime = null;
+    // OpenFlow edges keyed by head connector
+    private ConcurrentMap<NodeConnector, Edge> edgeMap = null;
+    // The map contains aging entry keyed by head connector of Production edge
+    private ConcurrentMap<NodeConnector, Integer> agingMap = null;
+    // Production edges keyed by head connector
+    private ConcurrentMap<NodeConnector, Edge> prodMap = null;
+
+    private Timer discoveryTimer;
+    private DiscoveryTimerTask discoveryTimerTask;
+    private final static long discoveryTimerTick = 2L * 1000; // per tick in msec
     private int discoveryTimerTickCount = 0; // main tick counter
-    private int discoveryBatchMaxPorts = 500; // max # of ports handled in one batch
-    private int discoveryBatchRestartTicks = 30; // periodically restart batching process
-    private int discoveryBatchPausePeriod = 2; // pause for few secs
-    private int discoveryBatchPauseTicks = discoveryBatchRestartTicks - discoveryBatchPausePeriod; // pause after this point
-    private int discoveryRetry = 1; // number of retry after initial timeout
-    private int discoveryTimeoutTicks = 2; // timeout 2 sec
-    private int discoveryAgeoutTicks = 120; // age out 2 min
-    private int discoveryConsistencyCheckMultiple = 2; // multiple of discoveryBatchRestartTicks
-    private int discoveryConsistencyCheckTickCount = discoveryBatchPauseTicks; // CC tick counter
-    private int discoveryConsistencyCheckCallingTimes = 0; // # of times CC gets called
-    private int discoveryConsistencyCheckCorrected = 0; // # of cases CC corrected
-    private boolean discoveryConsistencyCheckEnabled = true;// enable or disable CC
-    private boolean discoveryAgingEnabled = true; // enable or disable aging
-    private boolean discoverySpoofingEnabled = true; // enable or disable spoofing neighbor of a production network
-
+    // Max # of ports handled in one batch
+    private int discoveryBatchMaxPorts;
+    // Periodically restart batching process
+    private int discoveryBatchRestartTicks;
+    private int discoveryBatchPausePeriod = 2;
+    // Pause after this point
+    private int discoveryBatchPauseTicks;
+    private int discoveryTimeoutTicks;
+    private int discoveryThresholdTicks;
+    private int discoveryAgeoutTicks;
+    // multiple of discoveryBatchRestartTicks
+    private int discoveryConsistencyCheckMultiple = 2;
+    // CC tick counter
+    private int discoveryConsistencyCheckTickCount;
+    // # of times CC gets called
+    private int discoveryConsistencyCheckCallingTimes = 0;
+    // # of cases CC corrected
+    private int discoveryConsistencyCheckCorrected = 0;
+    // Enable or disable CC
+    private boolean discoveryConsistencyCheckEnabled = true;
+    // Enable or disable aging
+    private boolean discoveryAgingEnabled = true;
+    // Global flag to enable or disable LLDP snooping
+    private boolean discoverySnoopingEnabled = true;
+    // The list of ports that will not do LLDP snooping
+    private List<NodeConnector> discoverySnoopingDisableList;
     private BlockingQueue<NodeConnector> transmitQ;
     private Thread transmitThread;
     private Boolean throttling = false; // if true, no more batching.
     private volatile Boolean shuttingDown = false;
 
-    private LLDPTLV chassisIdTlv, portIdTlv, ttlTlv, customTlv;
+    private LLDPTLV chassisIdTlv, systemNameTlv, portIdTlv, ttlTlv, customTlv;
+    private IPluginOutConnectionService connectionOutService;
 
     class DiscoveryTransmit implements Runnable {
         private final BlockingQueue<NodeConnector> transmitQ;
+        private int count = 0;
 
         DiscoveryTransmit(BlockingQueue<NodeConnector> transmitQ) {
             this.transmitQ = transmitQ;
         }
 
+        @Override
         public void run() {
             while (true) {
                 try {
@@ -120,20 +144,23 @@ public class DiscoveryService implements IInventoryShimExternalListener,
                     RawPacket outPkt = createDiscoveryPacket(nodeConnector);
                     sendDiscoveryPacket(nodeConnector, outPkt);
                     nodeConnector = null;
+                    if ((++count & 0x7f) == 0) {
+                        Thread.sleep(10);
+                    }
                 } catch (InterruptedException e1) {
-                    logger
-                            .warn("DiscoveryTransmit interupted", e1
-                                    .getMessage());
-                    if (shuttingDown)
+                    logger.warn("DiscoveryTransmit interupted", e1.getMessage());
+                    if (shuttingDown) {
                         return;
+                    }
                 } catch (Exception e2) {
-                    logger.error("",e2);
+                    logger.error("", e2);
                 }
             }
         }
     }
 
     class DiscoveryTimerTask extends TimerTask {
+        @Override
         public void run() {
             checkTimeout();
             checkAging();
@@ -142,25 +169,68 @@ public class DiscoveryService implements IInventoryShimExternalListener,
         }
     }
 
+    public enum DiscoveryPeriod {
+        INTERVAL        (300),
+        AGEOUT          (120),
+        THRESHOLD       (30);
+
+        private int time;   // sec
+        private int tick;   // tick
+
+        DiscoveryPeriod(int time) {
+            this.time = time;
+            this.tick = time2Tick(time);
+        }
+
+        public int getTime() {
+            return time;
+        }
+
+        public void setTime(int time) {
+            this.time = time;
+            this.tick = time2Tick(time);
+        }
+
+        public int getTick() {
+            return tick;
+        }
+
+        public void setTick(int tick) {
+            this.time = tick2Time(tick);
+            this.tick = tick;
+        }
+
+        private int time2Tick(int time) {
+            return (int) (time / (discoveryTimerTick / 1000));
+        }
+
+        private int tick2Time(int tick) {
+            return (int) (tick * (discoveryTimerTick / 1000));
+        }
+    }
+
     private RawPacket createDiscoveryPacket(NodeConnector nodeConnector) {
-        String nodeId = HexEncode.longToHexString((Long) nodeConnector
-                .getNode().getID());
+        String nodeId = HexEncode.longToHexString((Long) nodeConnector.getNode().getID());
 
         // Create LLDP ChassisID TLV
         byte[] cidValue = LLDPTLV.createChassisIDTLVValue(nodeId);
-        chassisIdTlv.setType((byte) LLDPTLV.TLVType.ChassisID.getValue())
-                .setLength((short) cidValue.length).setValue(cidValue);
+        chassisIdTlv.setType(LLDPTLV.TLVType.ChassisID.getValue()).setLength((short) cidValue.length)
+                .setValue(cidValue);
+
+        // Create LLDP SystemName TLV
+        byte[] snValue = LLDPTLV.createSystemNameTLVValue(nodeConnector.getNode().toString());
+        systemNameTlv.setType(LLDPTLV.TLVType.SystemName.getValue()).setLength((short) snValue.length)
+                .setValue(snValue);
 
         // Create LLDP PortID TLV
         String portId = nodeConnector.getNodeConnectorIDString();
         byte[] pidValue = LLDPTLV.createPortIDTLVValue(portId);
-        portIdTlv.setType((byte) LLDPTLV.TLVType.PortID.getValue())
-                .setLength((short) pidValue.length).setValue(pidValue);
+        portIdTlv.setType(LLDPTLV.TLVType.PortID.getValue()).setLength((short) pidValue.length).setValue(pidValue);
 
         // Create LLDP Custom TLV
         byte[] customValue = LLDPTLV.createCustomTLVValue(nodeConnector.toString());
-        customTlv.setType((byte) LLDPTLV.TLVType.Custom.getValue())
-                .setLength((short) customValue.length).setValue(customValue);
+        customTlv.setType(LLDPTLV.TLVType.Custom.getValue()).setLength((short) customValue.length)
+                .setValue(customValue);
 
         // Create LLDP Custom Option list
         List<LLDPTLV> customList = new ArrayList<LLDPTLV>();
@@ -168,24 +238,22 @@ public class DiscoveryService implements IInventoryShimExternalListener,
 
         // Create discovery pkt
         LLDP discoveryPkt = new LLDP();
-        discoveryPkt.setChassisId(chassisIdTlv).setPortId(portIdTlv).setTtl(
-                ttlTlv).setOptionalTLVList(customList);
+        discoveryPkt.setChassisId(chassisIdTlv).setPortId(portIdTlv).setTtl(ttlTlv).setSystemNameId(systemNameTlv)
+                .setOptionalTLVList(customList);
 
         RawPacket rawPkt = null;
         try {
             // Create ethernet pkt
-               byte[] sourceMac = getSouceMACFromNodeID(nodeId);
+            byte[] sourceMac = getSourceMACFromNodeID(nodeId);
             Ethernet ethPkt = new Ethernet();
-            ethPkt.setSourceMACAddress(sourceMac).setDestinationMACAddress(
-                    LLDP.LLDPMulticastMac).setEtherType(
-                    EtherTypes.LLDP.shortValue()).setPayload(discoveryPkt);
+            ethPkt.setSourceMACAddress(sourceMac).setDestinationMACAddress(LLDP.LLDPMulticastMac)
+                    .setEtherType(EtherTypes.LLDP.shortValue()).setPayload(discoveryPkt);
 
             byte[] data = ethPkt.serialize();
             rawPkt = new RawPacket(data);
             rawPkt.setOutgoingNodeConnector(nodeConnector);
         } catch (ConstructionException cex) {
-            logger.warn("RawPacket creation caught exception {}", cex
-                    .getMessage());
+            logger.warn("RawPacket creation caught exception {}", cex.getMessage());
         } catch (Exception e) {
             logger.error("Failed to serialize the LLDP packet: " + e);
         }
@@ -193,13 +261,17 @@ public class DiscoveryService implements IInventoryShimExternalListener,
         return rawPkt;
     }
 
-    private void sendDiscoveryPacket(NodeConnector nodeConnector,
-            RawPacket outPkt) {
+    private void sendDiscoveryPacket(NodeConnector nodeConnector, RawPacket outPkt) {
         if (nodeConnector == null) {
             logger.debug("Can not send discovery packet out since nodeConnector is null");
             return;
         }
 
+        if (!connectionOutService.isLocal(nodeConnector.getNode())) {
+            logger.debug("Discoery packets will not be sent to {} in a non-master controller", nodeConnector.toString());
+            return;
+        }
+
         if (outPkt == null) {
             logger.debug("Can not send discovery packet out since outPkt is null");
             return;
@@ -245,43 +317,51 @@ public class DiscoveryService implements IInventoryShimExternalListener,
             return PacketResult.IGNORED;
         }
 
-        if (((Short) inPkt.getIncomingNodeConnector().getID())
-                .equals(NodeConnector.SPECIALNODECONNECTORID)) {
+        NodeConnector nodeConnector = inPkt.getIncomingNodeConnector();
+        if (((Short) nodeConnector.getID()).equals(NodeConnector.SPECIALNODECONNECTORID)) {
             logger.trace("Ignoring ethernet packet received on special port: "
                     + inPkt.getIncomingNodeConnector().toString());
             return PacketResult.IGNORED;
         }
 
+        if (!connectionOutService.isLocal(nodeConnector.getNode())) {
+            logger.debug("Discoery packets will not be processed from {} in a non-master controller", nodeConnector.toString());
+            return PacketResult.IGNORED;
+        }
+
         Ethernet ethPkt = new Ethernet();
         try {
             ethPkt.deserialize(data, 0, data.length * NetUtils.NumBitsInAByte);
         } catch (Exception e) {
-            logger.warn("Failed to decode LLDP packet from "
-                    + inPkt.getIncomingNodeConnector() + ": " + e);
+            logger.warn("Failed to decode LLDP packet from {}: {}", inPkt.getIncomingNodeConnector(), e);
             return PacketResult.IGNORED;
         }
+
         if (ethPkt.getPayload() instanceof LLDP) {
             NodeConnector dst = inPkt.getIncomingNodeConnector();
-            if (!processDiscoveryPacket(dst, ethPkt)) {
-                /* Spoof the discovery pkt if not generated from us */
-                spoofDiscoveryPacket(dst, ethPkt);
+            if (isEnabled(dst)) {
+                if (!processDiscoveryPacket(dst, ethPkt)) {
+                    // Snoop the discovery pkt if not generated from us
+                    snoopDiscoveryPacket(dst, ethPkt);
+                }
+                return PacketResult.CONSUME;
             }
-            return PacketResult.CONSUME;
         }
         return PacketResult.IGNORED;
     }
 
     /*
-     * Spoof incoming discovery frames generated by the production network neighbor switch
+     * Snoop incoming discovery frames generated by the production network
+     * neighbor switch
      */
-    private void spoofDiscoveryPacket(NodeConnector dstNodeConnector,
-            Ethernet ethPkt) {
-        if (!this.discoverySpoofingEnabled) {
+    private void snoopDiscoveryPacket(NodeConnector dstNodeConnector, Ethernet ethPkt) {
+        if (!this.discoverySnoopingEnabled || discoverySnoopingDisableList.contains(dstNodeConnector)) {
+            logger.trace("Discarded received discovery packet on {} since snooping is turned off", dstNodeConnector);
             return;
         }
 
         if ((dstNodeConnector == null) || (ethPkt == null)) {
-            logger.trace("Quit spoofing discovery packet: Null node connector or packet");
+            logger.trace("Quit snooping discovery packet: Null node connector or packet");
             return;
         }
 
@@ -290,19 +370,19 @@ public class DiscoveryService implements IInventoryShimExternalListener,
         try {
             String nodeId = LLDPTLV.getHexStringValue(lldp.getChassisId().getValue(), lldp.getChassisId().getLength());
             String portId = LLDPTLV.getStringValue(lldp.getPortId().getValue(), lldp.getPortId().getLength());
-                       byte[] systemNameBytes = null;
-               // get system name if present in the LLDP pkt 
-               for (LLDPTLV lldptlv : lldp.getOptionalTLVList()) {
-                       if (lldptlv.getType() == LLDPTLV.TLVType.SystemName.getValue()) {
-                               systemNameBytes = lldptlv.getValue();
-                               break;
-                       }
-               }
-                       String nodeName = (systemNameBytes == null) ? nodeId : new String(systemNameBytes);
-                       Node srcNode = new Node(Node.NodeIDType.PRODUCTION, nodeName);
-                       NodeConnector srcNodeConnector = NodeConnectorCreator
-                    .createNodeConnector(NodeConnector.NodeConnectorIDType.PRODUCTION,
-                               portId, srcNode);
+            byte[] systemNameBytes = null;
+            // get system name if present in the LLDP pkt
+            for (LLDPTLV lldptlv : lldp.getOptionalTLVList()) {
+                if (lldptlv.getType() == LLDPTLV.TLVType.SystemName.getValue()) {
+                    systemNameBytes = lldptlv.getValue();
+                    break;
+                }
+            }
+            String nodeName = (systemNameBytes == null) ? nodeId
+                    : new String(systemNameBytes, Charset.defaultCharset());
+            Node srcNode = new Node(Node.NodeIDType.PRODUCTION, nodeName);
+            NodeConnector srcNodeConnector = NodeConnectorCreator.createNodeConnector(
+                    NodeConnector.NodeConnectorIDType.PRODUCTION, portId, srcNode);
 
             Edge edge = null;
             Set<Property> props = null;
@@ -311,31 +391,33 @@ public class DiscoveryService implements IInventoryShimExternalListener,
 
             updateProdEdge(edge, props);
         } catch (Exception e) {
-            logger.warn("Caught exception ", e);
+            if (logger.isDebugEnabled()) {
+                logger.debug(
+                        "Caught exception while attempting to snoop non controller generated or malformed LLDP frame sent by {} and received on {}: {}",
+                        HexEncode.bytesToHexStringFormat(ethPkt.getSourceMACAddress()), dstNodeConnector,
+                        e.getMessage());
+            }
         }
     }
 
     /*
      * Handle discovery frames generated by our controller
+     *
      * @return true if it's a success
      */
-    private boolean processDiscoveryPacket(NodeConnector dstNodeConnector,
-            Ethernet ethPkt) {
+    private boolean processDiscoveryPacket(NodeConnector dstNodeConnector, Ethernet ethPkt) {
         if ((dstNodeConnector == null) || (ethPkt == null)) {
-            logger
-                    .trace("Ignoring processing of discovery packet: Null node connector or packet");
+            logger.trace("Ignoring processing of discovery packet: Null node connector or packet");
             return false;
         }
 
-        logger.trace("Handle discovery packet {} from {}", ethPkt,
-                dstNodeConnector);
+        logger.trace("Handle discovery packet {} from {}", ethPkt, dstNodeConnector);
 
         LLDP lldp = (LLDP) ethPkt.getPayload();
 
         List<LLDPTLV> optionalTLVList = lldp.getOptionalTLVList();
         if (optionalTLVList == null) {
-            logger.info("The discovery packet with null custom option from {}",
-                    dstNodeConnector);
+            logger.warn("The discovery packet with null custom option from {}", dstNodeConnector);
             return false;
         }
 
@@ -343,26 +425,16 @@ public class DiscoveryService implements IInventoryShimExternalListener,
         NodeConnector srcNodeConnector = null;
         for (LLDPTLV lldptlv : lldp.getOptionalTLVList()) {
             if (lldptlv.getType() == LLDPTLV.TLVType.Custom.getValue()) {
-               String ncString = LLDPTLV.getCustomString(lldptlv.getValue(), lldptlv.getLength());
-               srcNodeConnector = NodeConnector.fromString(ncString);
-               if (srcNodeConnector != null) {
-                       srcNode = srcNodeConnector.getNode();
-                       /* Check if it's expected */
-                       if (isTracked(srcNodeConnector)) {
-                               break;
-                    } else {
-                       srcNode = null;
-                       srcNodeConnector = null;
-                    }
+                String ncString = LLDPTLV.getCustomString(lldptlv.getValue(), lldptlv.getLength());
+                srcNodeConnector = NodeConnector.fromString(ncString);
+                if (srcNodeConnector != null) {
+                    srcNode = srcNodeConnector.getNode();
                 }
             }
         }
 
         if ((srcNode == null) || (srcNodeConnector == null)) {
-            logger
-                    .trace(
-                            "Received non-controller generated discovery packet from {}",
-                            dstNodeConnector);
+            logger.trace("Received non-controller generated discovery packet from {}", dstNodeConnector);
             return false;
         }
 
@@ -387,12 +459,11 @@ public class DiscoveryService implements IInventoryShimExternalListener,
             return null;
         }
 
-        if (pluginInInventoryService == null) {
+        if (inventoryProvider == null) {
             return null;
         }
 
-        Map<NodeConnector, Map<String, Property>> props = pluginInInventoryService
-                .getNodeConnectorProps(false);
+        Map<NodeConnector, Map<String, Property>> props = inventoryProvider.getNodeConnectorProps(false);
         if (props == null) {
             return null;
         }
@@ -406,7 +477,7 @@ public class DiscoveryService implements IInventoryShimExternalListener,
             return null;
         }
 
-        Property prop = (Property) propMap.get(propName);
+        Property prop = propMap.get(propName);
         return prop;
     }
 
@@ -427,8 +498,7 @@ public class DiscoveryService implements IInventoryShimExternalListener,
 
         Config config = (Config) getProp(nodeConnector, Config.ConfigPropName);
         State state = (State) getProp(nodeConnector, State.StatePropName);
-        return ((config != null) && (config.getValue() == Config.ADMIN_UP)
-                && (state != null) && (state.getValue() == State.EDGE_UP));
+        return ((config != null) && (config.getValue() == Config.ADMIN_UP) && (state != null) && (state.getValue() == State.EDGE_UP));
     }
 
     private boolean isTracked(NodeConnector nodeConnector) {
@@ -440,11 +510,11 @@ public class DiscoveryService implements IInventoryShimExternalListener,
             return true;
         }
 
-        if (pendingMap.keySet().contains(nodeConnector)) {
+        if (holdTime.keySet().contains(nodeConnector)) {
             return true;
         }
 
-        if (waitingList.contains(nodeConnector)) {
+        if (stagingList.contains(nodeConnector)) {
             return true;
         }
 
@@ -462,6 +532,9 @@ public class DiscoveryService implements IInventoryShimExternalListener,
 
             workingSet.add(nodeConnector);
             removeSet.add(nodeConnector);
+
+            // Put it in the map and start the timer. It may need retry.
+            elapsedTime.put(nodeConnector, 0);
         }
         readyListHi.removeAll(removeSet);
 
@@ -497,14 +570,14 @@ public class DiscoveryService implements IInventoryShimExternalListener,
 
     private void addDiscovery(Node node) {
         Map<Long, ISwitch> switches = controller.getSwitches();
-        ISwitch sw = switches.get((Long) node.getID());
-        List<OFPhysicalPort> ports = sw.getEnabledPorts();
-        if (ports == null) {
+        ISwitch sw = switches.get(node.getID());
+        if (sw == null) {
+            //switch could be removed by now, stop propagation
             return;
         }
+        List<OFPhysicalPort> ports = sw.getEnabledPorts();
         for (OFPhysicalPort port : ports) {
-            NodeConnector nodeConnector = NodeConnectorCreator
-                    .createOFNodeConnector(port.getPortNumber(), node);
+            NodeConnector nodeConnector = NodeConnectorCreator.createOFNodeConnector(port.getPortNumber(), node);
             if (!readyListHi.contains(nodeConnector)) {
                 readyListHi.add(nodeConnector);
             }
@@ -519,8 +592,15 @@ public class DiscoveryService implements IInventoryShimExternalListener,
         readyListHi.add(nodeConnector);
     }
 
-    private Set<NodeConnector> getRemoveSet(Collection<NodeConnector> c,
-            Node node) {
+    private void removeNodeConnector(NodeConnector nodeConnector) {
+        readyListLo.remove(nodeConnector);
+        readyListHi.remove(nodeConnector);
+        stagingList.remove(nodeConnector);
+        holdTime.remove(nodeConnector);
+        elapsedTime.remove(nodeConnector);
+    }
+
+    private Set<NodeConnector> getRemoveSet(Collection<NodeConnector> c, Node node) {
         Set<NodeConnector> removeSet = new HashSet<NodeConnector>();
         if (c == null) {
             return removeSet;
@@ -536,56 +616,68 @@ public class DiscoveryService implements IInventoryShimExternalListener,
     private void removeDiscovery(Node node) {
         Set<NodeConnector> removeSet;
 
+        removeSet = getRemoveSet(edgeMap.keySet(), node);
+        NodeConnector peerConnector;
+        Edge edge1, edge2;
+        for (NodeConnector nodeConnector : removeSet) {
+            // get the peer for fast removal of the edge in reverse direction
+            peerConnector = null;
+            edge1 = edgeMap.get(nodeConnector);
+            if (edge1 != null) {
+                edge2 = edgeMap.get(edge1.getTailNodeConnector());
+                if ((edge2 != null) && node.equals(edge2.getTailNodeConnector().getNode())) {
+                    peerConnector = edge2.getHeadNodeConnector();
+                }
+            }
+
+            removeEdge(nodeConnector, false);
+            removeEdge(peerConnector, isEnabled(peerConnector));
+        }
+
+        removeSet = getRemoveSet(prodMap.keySet(), node);
+        for (NodeConnector nodeConnector : removeSet) {
+            removeProdEdge(nodeConnector);
+        }
+
         removeSet = getRemoveSet(readyListHi, node);
         readyListHi.removeAll(removeSet);
 
         removeSet = getRemoveSet(readyListLo, node);
         readyListLo.removeAll(removeSet);
 
-        removeSet = getRemoveSet(waitingList, node);
-        waitingList.removeAll(removeSet);
+        removeSet = getRemoveSet(stagingList, node);
+        stagingList.removeAll(removeSet);
 
-        removeSet = getRemoveSet(pendingMap.keySet(), node);
+        removeSet = getRemoveSet(holdTime.keySet(), node);
         for (NodeConnector nodeConnector : removeSet) {
-            pendingMap.remove(nodeConnector);
+            holdTime.remove(nodeConnector);
         }
 
-        removeSet = getRemoveSet(edgeMap.keySet(), node);
-        for (NodeConnector nodeConnector : removeSet) {
-            removeEdge(nodeConnector, false);
-        }
-
-        removeSet = getRemoveSet(prodMap.keySet(), node);
+        removeSet = getRemoveSet(elapsedTime.keySet(), node);
         for (NodeConnector nodeConnector : removeSet) {
-            removeProdEdge(nodeConnector);
+            elapsedTime.remove(nodeConnector);
         }
     }
 
     private void removeDiscovery(NodeConnector nodeConnector) {
-        readyListHi.remove(nodeConnector);
-        readyListLo.remove(nodeConnector);
-        waitingList.remove(nodeConnector);
-        pendingMap.remove(nodeConnector);
+        removeNodeConnector(nodeConnector);
         removeEdge(nodeConnector, false);
         removeProdEdge(nodeConnector);
     }
 
     private void checkTimeout() {
         Set<NodeConnector> removeSet = new HashSet<NodeConnector>();
-        Set<NodeConnector> retrySet = new HashSet<NodeConnector>();
-        int sentCount;
-
-        Set<NodeConnector> pendingSet = pendingMap.keySet();
-        if (pendingSet != null) {
-            for (NodeConnector nodeConnector : pendingSet) {
-                sentCount = pendingMap.get(nodeConnector);
-                pendingMap.put(nodeConnector, ++sentCount);
-                if (sentCount > getDiscoveryFinalTimeoutInterval()) {
+        int ticks;
+
+        Set<NodeConnector> monitorSet = holdTime.keySet();
+        if (monitorSet != null) {
+            for (NodeConnector nodeConnector : monitorSet) {
+                ticks = holdTime.get(nodeConnector);
+                holdTime.put(nodeConnector, ++ticks);
+                if (ticks >= discoveryTimeoutTicks) {
                     // timeout the edge
                     removeSet.add(nodeConnector);
                     logger.trace("Discovery timeout {}", nodeConnector);
-                } else if (sentCount % discoveryTimeoutTicks == 0) {
-                    retrySet.add(nodeConnector);
                 }
             }
         }
@@ -594,8 +686,24 @@ public class DiscoveryService implements IInventoryShimExternalListener,
             removeEdge(nodeConnector);
         }
 
-        for (NodeConnector nodeConnector : retrySet) {
-            transmitQ.add(nodeConnector);
+        Set<NodeConnector> retrySet = new HashSet<NodeConnector>();
+        Set<NodeConnector> ncSet = elapsedTime.keySet();
+        if ((ncSet != null) && (ncSet.size() > 0)) {
+            for (NodeConnector nodeConnector : ncSet) {
+                ticks = elapsedTime.get(nodeConnector);
+                elapsedTime.put(nodeConnector, ++ticks);
+                if (ticks >= discoveryThresholdTicks) {
+                    retrySet.add(nodeConnector);
+                }
+            }
+
+            for (NodeConnector nodeConnector : retrySet) {
+                // Allow one more retry
+                elapsedTime.remove(nodeConnector);
+                if (connectionOutService.isLocal(nodeConnector.getNode())) {
+                    transmitQ.add(nodeConnector);
+                }
+            }
         }
     }
 
@@ -605,14 +713,14 @@ public class DiscoveryService implements IInventoryShimExternalListener,
         }
 
         Set<NodeConnector> removeSet = new HashSet<NodeConnector>();
-        int sentCount;
+        int ticks;
 
         Set<NodeConnector> agingSet = agingMap.keySet();
         if (agingSet != null) {
             for (NodeConnector nodeConnector : agingSet) {
-                sentCount = agingMap.get(nodeConnector);
-                agingMap.put(nodeConnector, ++sentCount);
-                if (sentCount > discoveryAgeoutTicks) {
+                ticks = agingMap.get(nodeConnector);
+                agingMap.put(nodeConnector, ++ticks);
+                if (ticks > discoveryAgeoutTicks) {
                     // age out the edge
                     removeSet.add(nodeConnector);
                     logger.trace("Discovery age out {}", nodeConnector);
@@ -628,16 +736,22 @@ public class DiscoveryService implements IInventoryShimExternalListener,
     private void doDiscovery() {
         if (++discoveryTimerTickCount <= discoveryBatchPauseTicks) {
             for (NodeConnector nodeConnector : getWorkingSet()) {
-                pendingMap.put(nodeConnector, 0);
-                transmitQ.add(nodeConnector);
+                if (connectionOutService.isLocal(nodeConnector.getNode())) {
+                    transmitQ.add(nodeConnector);
+                    // Move to staging area after it's served
+                    if (!stagingList.contains(nodeConnector)) {
+                        stagingList.add(nodeConnector);
+                    }
+                }
             }
         } else if (discoveryTimerTickCount >= discoveryBatchRestartTicks) {
             discoveryTimerTickCount = 0;
-            for (NodeConnector nodeConnector : waitingList) {
-                if (!readyListLo.contains(nodeConnector))
+            for (NodeConnector nodeConnector : stagingList) {
+                if (!readyListLo.contains(nodeConnector)) {
                     readyListLo.add(nodeConnector);
+                }
             }
-            waitingList.removeAll(readyListLo);
+            stagingList.removeAll(readyListLo);
         }
     }
 
@@ -646,8 +760,7 @@ public class DiscoveryService implements IInventoryShimExternalListener,
             return;
         }
 
-        if (++discoveryConsistencyCheckTickCount
-                % getDiscoveryConsistencyCheckInterval() != 0) {
+        if (++discoveryConsistencyCheckTickCount % getDiscoveryConsistencyCheckInterval() != 0) {
             return;
         }
 
@@ -662,16 +775,14 @@ public class DiscoveryService implements IInventoryShimExternalListener,
             if (!isEnabled(nodeConnector)) {
                 removeSet.add(nodeConnector);
                 discoveryConsistencyCheckCorrected++;
-                logger.debug("ConsistencyChecker: remove disabled {}",
-                        nodeConnector);
+                logger.debug("ConsistencyChecker: remove disabled {}", nodeConnector);
                 continue;
             }
 
             if (!isTracked(nodeConnector)) {
-                waitingList.add(nodeConnector);
+                stagingList.add(nodeConnector);
                 discoveryConsistencyCheckCorrected++;
-                logger.debug("ConsistencyChecker: add back untracked {}",
-                        nodeConnector);
+                logger.debug("ConsistencyChecker: add back untracked {}", nodeConnector);
                 continue;
             }
         }
@@ -682,28 +793,25 @@ public class DiscoveryService implements IInventoryShimExternalListener,
 
         // remove stale entries
         removeSet.clear();
-        for (NodeConnector nodeConnector : waitingList) {
+        for (NodeConnector nodeConnector : stagingList) {
             if (!isEnabled(nodeConnector)) {
                 removeSet.add(nodeConnector);
                 discoveryConsistencyCheckCorrected++;
-                logger.debug("ConsistencyChecker: remove disabled {}",
-                        nodeConnector);
+                logger.debug("ConsistencyChecker: remove disabled {}", nodeConnector);
             }
         }
-        waitingList.removeAll(removeSet);
+        stagingList.removeAll(removeSet);
 
         // Get a snapshot of all the existing switches
         Map<Long, ISwitch> switches = this.controller.getSwitches();
         for (ISwitch sw : switches.values()) {
             for (OFPhysicalPort port : sw.getEnabledPorts()) {
                 Node node = NodeCreator.createOFNode(sw.getId());
-                NodeConnector nodeConnector = NodeConnectorCreator
-                        .createOFNodeConnector(port.getPortNumber(), node);
+                NodeConnector nodeConnector = NodeConnectorCreator.createOFNodeConnector(port.getPortNumber(), node);
                 if (!isTracked(nodeConnector)) {
-                    waitingList.add(nodeConnector);
+                    stagingList.add(nodeConnector);
                     discoveryConsistencyCheckCorrected++;
-                    logger.debug("ConsistencyChecker: add back untracked {}",
-                            nodeConnector);
+                    logger.debug("ConsistencyChecker: add back untracked {}", nodeConnector);
                 }
             }
         }
@@ -715,60 +823,65 @@ public class DiscoveryService implements IInventoryShimExternalListener,
         }
 
         NodeConnector src = edge.getTailNodeConnector();
-        if (!src.getType().equals(
-                NodeConnector.NodeConnectorIDType.PRODUCTION)) {
-            pendingMap.remove(src);
-            if (!waitingList.contains(src)) {
-                waitingList.add(src);
-            }
+        NodeConnector dst = edge.getHeadNodeConnector();
+        if (!src.getType().equals(NodeConnector.NodeConnectorIDType.PRODUCTION)) {
+            holdTime.put(dst, 0);
         } else {
-            NodeConnector dst = edge.getHeadNodeConnector();
             agingMap.put(dst, 0);
         }
+        elapsedTime.remove(src);
 
-        // notify routeEngine
-        updateEdge(edge, UpdateType.ADDED, props);
+        // fast discovery of the edge in reverse direction
+        if (!edgeMap.containsKey(dst) && !readyListHi.contains(dst) && !elapsedTime.keySet().contains(dst)) {
+            moveToReadyListHi(dst);
+        }
+
+        //checking only OF map, since production edge discovery always overwrites any existing edge
+        UpdateType ut = edgeMap.containsKey(dst) ? UpdateType.CHANGED : UpdateType.ADDED;
+        // notify
+        updateEdge(edge, ut, props);
         logger.trace("Add edge {}", edge);
     }
 
-    
     /**
      * Update Production Edge
-     * 
-     * @param edge The Production Edge
-     * @param props Properties associated with the edge
+     *
+     * @param edge
+     *            The Production Edge
+     * @param props
+     *            Properties associated with the edge
      */
     private void updateProdEdge(Edge edge, Set<Property> props) {
-       NodeConnector edgePort = edge.getHeadNodeConnector();
-       
-       /* Do not update in case there is an existing OpenFlow link */
-       if (edgeMap.get(edgePort) != null) {
-               logger.trace("Discarded edge {} since there is an existing OF link {}",
-                               edge, edgeMap.get(edgePort));
-               return;
-       }
-       
-       /* Look for any existing Production Edge */
-       Edge oldEdge = prodMap.get(edgePort);           
-       if (oldEdge == null) {
-               /* Let's add a new one */
-               addEdge(edge, props);
-       } else if (!edge.equals(oldEdge)) {
-               /* Remove the old one first */
-               removeProdEdge(oldEdge.getHeadNodeConnector());
-               /* Then add the new one */
-               addEdge(edge, props);                   
-       } else {
-               /* o/w, just reset the aging timer */
+        NodeConnector edgePort = edge.getHeadNodeConnector();
+
+        /* Do not update in case there is an existing OpenFlow link */
+        if (edgeMap.get(edgePort) != null) {
+            logger.trace("Discarded edge {} since there is an existing OF link {}", edge, edgeMap.get(edgePort));
+            return;
+        }
+
+        /* Look for any existing Production Edge */
+        Edge oldEdge = prodMap.get(edgePort);
+        if (oldEdge == null) {
+            /* Let's add a new one */
+            addEdge(edge, props);
+        } else if (!edge.equals(oldEdge)) {
+            /* Remove the old one first */
+            removeProdEdge(oldEdge.getHeadNodeConnector());
+            /* Then add the new one */
+            addEdge(edge, props);
+        } else {
+            /* o/w, just reset the aging timer */
             NodeConnector dst = edge.getHeadNodeConnector();
-            agingMap.put(dst, 0);              
-       }
+            agingMap.put(dst, 0);
+        }
     }
 
     /**
      * Remove Production Edge for a given edge port
-     * 
-     * @param edgePort The OF edge port
+     *
+     * @param edgePort
+     *            The OF edge port
      */
     private void removeProdEdge(NodeConnector edgePort) {
         agingMap.remove(edgePort);
@@ -781,8 +894,8 @@ public class DiscoveryService implements IInventoryShimExternalListener,
         }
 
         // notify Topology
-        if (this.discoveryService != null) {
-            this.discoveryService.notifyEdge(edge, UpdateType.REMOVED, null);
+        if (this.discoveryListener != null) {
+            this.discoveryListener.notifyEdge(edge, UpdateType.REMOVED, null);
         }
         logger.trace("Remove edge {}", edge);
     }
@@ -791,18 +904,15 @@ public class DiscoveryService implements IInventoryShimExternalListener,
      * Remove OpenFlow edge
      */
     private void removeEdge(NodeConnector nodeConnector, boolean stillEnabled) {
-        pendingMap.remove(nodeConnector);
-        readyListLo.remove(nodeConnector);
-        readyListHi.remove(nodeConnector);
+        if (nodeConnector == null) {
+            return;
+        }
+
+        removeNodeConnector(nodeConnector);
 
         if (stillEnabled) {
             // keep discovering
-            if (!waitingList.contains(nodeConnector)) {
-                waitingList.add(nodeConnector);
-            }
-        } else {
-            // stop it
-            waitingList.remove(nodeConnector);
+            stagingList.add(nodeConnector);
         }
 
         Edge edge = null;
@@ -813,8 +923,8 @@ public class DiscoveryService implements IInventoryShimExternalListener,
         }
 
         // notify Topology
-        if (this.discoveryService != null) {
-            this.discoveryService.notifyEdge(edge, UpdateType.REMOVED, null);
+        if (this.discoveryListener != null) {
+            this.discoveryListener.notifyEdge(edge, UpdateType.REMOVED, null);
         }
         logger.trace("Remove {}", nodeConnector);
     }
@@ -824,20 +934,19 @@ public class DiscoveryService implements IInventoryShimExternalListener,
     }
 
     private void updateEdge(Edge edge, UpdateType type, Set<Property> props) {
-        if (discoveryService == null) {
+        if (discoveryListener == null) {
             return;
         }
 
-        this.discoveryService.notifyEdge(edge, type, props);
 
-        NodeConnector src = edge.getTailNodeConnector(), dst = edge
-                .getHeadNodeConnector();
-        if (!src.getType().equals(
-                NodeConnector.NodeConnectorIDType.PRODUCTION)) {
+        this.discoveryListener.notifyEdge(edge, type, props);
+
+        NodeConnector src = edge.getTailNodeConnector(), dst = edge.getHeadNodeConnector();
+        if (!src.getType().equals(NodeConnector.NodeConnectorIDType.PRODUCTION)) {
             if (type == UpdateType.ADDED) {
-                edgeMap.put(src, edge);
+                edgeMap.put(dst, edge);
             } else {
-                edgeMap.remove(src);
+                edgeMap.remove(dst);
             }
         } else {
             /*
@@ -851,101 +960,121 @@ public class DiscoveryService implements IInventoryShimExternalListener,
         }
     }
 
-    private void moreToReadyListHi(NodeConnector nodeConnector) {
+    private void moveToReadyListHi(NodeConnector nodeConnector) {
         if (readyListLo.contains(nodeConnector)) {
             readyListLo.remove(nodeConnector);
-            readyListHi.add(nodeConnector);
-        } else if (waitingList.contains(nodeConnector)) {
-            waitingList.remove(nodeConnector);
-            readyListHi.add(nodeConnector);
+        } else if (stagingList.contains(nodeConnector)) {
+            stagingList.remove(nodeConnector);
         }
+        readyListHi.add(nodeConnector);
     }
 
     private void registerWithOSGIConsole() {
-        BundleContext bundleContext = FrameworkUtil.getBundle(this.getClass())
-                .getBundleContext();
-        bundleContext.registerService(CommandProvider.class.getName(), this,
-                null);
+        BundleContext bundleContext = FrameworkUtil.getBundle(this.getClass()).getBundleContext();
+        bundleContext.registerService(CommandProvider.class.getName(), this, null);
     }
 
     private int getDiscoveryConsistencyCheckInterval() {
         return discoveryConsistencyCheckMultiple * discoveryBatchRestartTicks;
     }
 
-    private int getDiscoveryFinalTimeoutInterval() {
-        return (discoveryRetry + 1) * discoveryTimeoutTicks;
-    }
-
     @Override
     public String getHelp() {
         StringBuffer help = new StringBuffer();
         help.append("---Topology Discovery---\n");
-        help.append("\t prlh                   - Print readyListHi entries\n");
-        help.append("\t prll                   - Print readyListLo entries\n");
-        help.append("\t pwl                    - Print waitingList entries\n");
-        help.append("\t ppl                    - Print pendingList entries\n");
-        help.append("\t ptick                  - Print tick time in msec\n");
-        help.append("\t pcc                    - Print CC info\n");
-        help.append("\t psize                  - Print sizes of all the lists\n");
-        help.append("\t ptm                    - Print timeout info\n");
-        help.append("\t ecc                       - Enable CC\n");
-        help.append("\t dcc                       - Disable CC\n");
-        help.append("\t scc [multiple]         - Set/show CC multiple and interval\n");
-        help.append("\t sports [ports]                    - Set/show max ports per batch\n");
-        help.append("\t spause [ticks]         - Set/show pause period\n");
-        help.append("\t sdi [ticks]               - Set/show discovery interval in ticks\n");
-        help.append("\t stm [ticks]            - Set/show per timeout ticks\n");
-        help.append("\t sretry [count]                    - Set/show num of retries\n");
-        help.append("\t addsw <swid>              - Add a switch\n");
-        help.append("\t remsw <swid>              - Remove a switch\n");
-        help.append("\t page                   - Print aging info\n");
-        help.append("\t sage                   - Set/Show aging time limit\n");
-        help.append("\t eage                      - Enable aging\n");
-        help.append("\t dage                      - Disable aging\n");
-        help.append("\t pthrot                 - Print throttling\n");
-        help.append("\t ethrot                    - Enable throttling\n");
-        help.append("\t dthrot                 - Disable throttling\n");
+        help.append("\t prlh                            - Print readyListHi entries\n");
+        help.append("\t prll                            - Print readyListLo entries\n");
+        help.append("\t psl                             - Print stagingList entries\n");
+        help.append("\t pht                             - Print hold time\n");
+        help.append("\t pet                             - Print elapsed time\n");
+        help.append("\t ptick                           - Print tick time in msec\n");
+        help.append("\t pcc                             - Print CC info\n");
+        help.append("\t psize                           - Print sizes of all the lists\n");
+        help.append("\t ptm                             - Print timeout info\n");
+        help.append("\t ecc                             - Enable CC\n");
+        help.append("\t dcc                             - Disable CC\n");
+        help.append("\t scc [multiple]                  - Set/show CC multiple and interval\n");
+        help.append("\t sports [ports]                  - Set/show max ports per batch\n");
+        help.append("\t spause [ticks]                  - Set/show pause period\n");
+        help.append("\t sdi [ticks]                     - Set/show discovery interval in ticks\n");
+        help.append("\t addsw <swid>                    - Add a switch\n");
+        help.append("\t remsw <swid>                    - Remove a switch\n");
+        help.append("\t page                            - Print aging info\n");
+        help.append("\t sage                            - Set/Show aging time limit\n");
+        help.append("\t eage                            - Enable aging\n");
+        help.append("\t dage                            - Disable aging\n");
+        help.append("\t pthrot                          - Print throttling\n");
+        help.append("\t ethrot                          - Enable throttling\n");
+        help.append("\t dthrot                          - Disable throttling\n");
+        help.append("\t psnp                            - Print LLDP snooping\n");
+        help.append("\t esnp <all|nodeConnector>        - Enable LLDP snooping\n");
+        help.append("\t dsnp <all|nodeConnector>        - Disable LLDP snooping\n");
         return help.toString();
     }
 
+    private List<NodeConnector> sortList(Collection<NodeConnector> ncs) {
+        List<String> ncStrArray = new ArrayList<String>();
+        for (NodeConnector nc : ncs) {
+            ncStrArray.add(nc.toString());
+        }
+        Collections.sort(ncStrArray);
+
+        List<NodeConnector> sortedNodeConnectors = new ArrayList<NodeConnector>();
+        for (String ncStr : ncStrArray) {
+            sortedNodeConnectors.add(NodeConnector.fromString(ncStr));
+        }
+
+        return sortedNodeConnectors;
+    }
+
     public void _prlh(CommandInterpreter ci) {
-        ci.println("ReadyListHi\n");
-        for (NodeConnector nodeConnector : readyListHi) {
+        ci.println("readyListHi\n");
+        for (NodeConnector nodeConnector : sortList(readyListHi)) {
             if (nodeConnector == null) {
                 continue;
             }
             ci.println(nodeConnector);
         }
+        ci.println("Total number of Node Connectors: " + readyListHi.size());
     }
 
     public void _prll(CommandInterpreter ci) {
-        ci.println("ReadyListLo\n");
-        for (NodeConnector nodeConnector : readyListLo) {
+        ci.println("readyListLo\n");
+        for (NodeConnector nodeConnector : sortList(readyListLo)) {
             if (nodeConnector == null) {
                 continue;
             }
             ci.println(nodeConnector);
         }
+        ci.println("Total number of Node Connectors: " + readyListLo.size());
     }
 
-    public void _pwl(CommandInterpreter ci) {
-        ci.println("WaitingList\n");
-        for (NodeConnector nodeConnector : waitingList) {
+    public void _psl(CommandInterpreter ci) {
+        ci.println("stagingList\n");
+        for (NodeConnector nodeConnector : sortList(stagingList)) {
             if (nodeConnector == null) {
                 continue;
             }
             ci.println(nodeConnector);
         }
+        ci.println("Total number of Node Connectors: " + stagingList.size());
     }
 
-    public void _ppl(CommandInterpreter ci) {
-        ci.println("PendingList\n");
-        for (NodeConnector nodeConnector : pendingMap.keySet()) {
-            if (nodeConnector == null) {
-                continue;
-            }
-            ci.println(nodeConnector);
+    public void _pht(CommandInterpreter ci) {
+        ci.println("          NodeConnector            Last rx LLDP (sec)");
+        for (ConcurrentMap.Entry<NodeConnector, Integer> entry: holdTime.entrySet()) {
+            ci.println(entry.getKey() + "\t\t" + entry.getValue() * (discoveryTimerTick / 1000));
         }
+        ci.println("\nSize: " + holdTime.size() + "\tTimeout: " + discoveryTimeoutTicks * (discoveryTimerTick / 1000)
+                + " sec");
+    }
+
+    public void _pet(CommandInterpreter ci) {
+        ci.println("          NodeConnector            Elapsed Time (sec)");
+        for (ConcurrentMap.Entry<NodeConnector, Integer> entry: elapsedTime.entrySet()) {
+            ci.println(entry.getKey() + "\t\t" + entry.getValue() * (discoveryTimerTick / 1000));
+        }
+        ci.println("\nSize: " + elapsedTime.size() + "\tThreshold: " + DiscoveryPeriod.THRESHOLD.getTime() + " sec");
     }
 
     public void _ptick(CommandInterpreter ci) {
@@ -960,24 +1089,19 @@ public class DiscoveryService implements IInventoryShimExternalListener,
         }
         ci.println("Interval " + getDiscoveryConsistencyCheckInterval());
         ci.println("Multiple " + discoveryConsistencyCheckMultiple);
-        ci.println("Number of times called "
-                + discoveryConsistencyCheckCallingTimes);
+        ci.println("Number of times called " + discoveryConsistencyCheckCallingTimes);
         ci.println("Corrected count " + discoveryConsistencyCheckCorrected);
     }
 
     public void _ptm(CommandInterpreter ci) {
-        ci.println("Final timeout ticks " + getDiscoveryFinalTimeoutInterval());
-        ci.println("Per timeout ticks " + discoveryTimeoutTicks);
-        ci.println("Retry after initial timeout " + discoveryRetry);
+        ci.println("Timeout " + discoveryTimeoutTicks + " ticks, " + discoveryTimerTick / 1000 + " sec per tick.");
     }
 
     public void _psize(CommandInterpreter ci) {
-        ci.println("readyListLo size " + readyListLo.size() + "\n"
-                + "readyListHi size " + readyListHi.size() + "\n"
-                + "waitingList size " + waitingList.size() + "\n"
-                + "pendingMap size " + pendingMap.size() + "\n"
-                + "edgeMap size " + edgeMap.size() + "\n" + "prodMap size "
-                + prodMap.size() + "\n" + "agingMap size " + agingMap.size());
+        ci.println("readyListLo size " + readyListLo.size() + "\n" + "readyListHi size " + readyListHi.size() + "\n"
+                + "stagingList size " + stagingList.size() + "\n" + "holdTime size " + holdTime.size() + "\n"
+                + "edgeMap size " + edgeMap.size() + "\n" + "prodMap size " + prodMap.size() + "\n" + "agingMap size "
+                + agingMap.size() + "\n" + "elapsedTime size " + elapsedTime.size());
     }
 
     public void _page(CommandInterpreter ci) {
@@ -1000,7 +1124,7 @@ public class DiscoveryService implements IInventoryShimExternalListener,
             }
         }
         ci.println("\n");
-        ci.println("              NodeConnector                                                Edge ");
+        ci.println("              NodeConnector                                                 Edge ");
         Set<NodeConnector> keySet = prodMap.keySet();
         if (keySet == null) {
             return;
@@ -1014,8 +1138,7 @@ public class DiscoveryService implements IInventoryShimExternalListener,
     public void _sage(CommandInterpreter ci) {
         String val = ci.nextArgument();
         if (val == null) {
-            ci.println("Please enter aging time limit. Current value "
-                    + this.discoveryAgeoutTicks);
+            ci.println("Please enter aging time limit. Current value " + this.discoveryAgeoutTicks);
             return;
         }
         try {
@@ -1041,10 +1164,8 @@ public class DiscoveryService implements IInventoryShimExternalListener,
     public void _scc(CommandInterpreter ci) {
         String val = ci.nextArgument();
         if (val == null) {
-            ci.println("Please enter CC multiple. Current multiple "
-                    + discoveryConsistencyCheckMultiple + " (interval "
-                    + getDiscoveryConsistencyCheckInterval()
-                    + ") calling times "
+            ci.println("Please enter CC multiple. Current multiple " + discoveryConsistencyCheckMultiple
+                    + " (interval " + getDiscoveryConsistencyCheckInterval() + ") calling times "
                     + discoveryConsistencyCheckCallingTimes);
             return;
         }
@@ -1068,40 +1189,72 @@ public class DiscoveryService implements IInventoryShimExternalListener,
         return;
     }
 
-    public void _pspf(CommandInterpreter ci) {
-        if (this.discoverySpoofingEnabled) {
-            ci.println("Discovery spoofing is enabled");
+    public void _psnp(CommandInterpreter ci) {
+        if (this.discoverySnoopingEnabled) {
+            ci.println("Discovery snooping is globally enabled");
         } else {
-            ci.println("Discovery spoofing is disabled");
+            ci.println("Discovery snooping is globally disabled");
+        }
+
+        ci.println("\nDiscovery snooping is locally disabled on these ports");
+        for (NodeConnector nodeConnector : discoverySnoopingDisableList) {
+            ci.println(nodeConnector);
         }
         return;
     }
 
-    public void _espf(CommandInterpreter ci) {
-        this.discoverySpoofingEnabled = true;
-        ci.println("Discovery spoofing is enabled");
+    public void _esnp(CommandInterpreter ci) {
+        String val = ci.nextArgument();
+
+        if (val == null) {
+            ci.println("Usage: esnp <all|nodeConnector>");
+        } else if (val.equalsIgnoreCase("all")) {
+            this.discoverySnoopingEnabled = true;
+            ci.println("Discovery snooping is globally enabled");
+        } else {
+            NodeConnector nodeConnector = NodeConnector.fromString(val);
+            if (nodeConnector != null) {
+                discoverySnoopingDisableList.remove(nodeConnector);
+                ci.println("Discovery snooping is locally enabled on port " + nodeConnector);
+            } else {
+                ci.println("Entered invalid NodeConnector " + val);
+            }
+        }
         return;
     }
 
-    public void _dspf(CommandInterpreter ci) {
-        this.discoverySpoofingEnabled = false;
-        ci.println("Discovery spoofing is disabled");
+    public void _dsnp(CommandInterpreter ci) {
+        String val = ci.nextArgument();
+
+        if (val == null) {
+            ci.println("Usage: dsnp <all|nodeConnector>");
+        } else if (val.equalsIgnoreCase("all")) {
+            this.discoverySnoopingEnabled = false;
+            ci.println("Discovery snooping is globally disabled");
+        } else {
+            NodeConnector nodeConnector = NodeConnector.fromString(val);
+            if (nodeConnector != null) {
+                discoverySnoopingDisableList.add(nodeConnector);
+                ci.println("Discovery snooping is locally disabled on port " + nodeConnector);
+            } else {
+                ci.println("Entered invalid NodeConnector " + val);
+            }
+        }
         return;
     }
 
     public void _spause(CommandInterpreter ci) {
         String val = ci.nextArgument();
-        String out = "Please enter pause period less than "
-                               + discoveryBatchRestartTicks + ". Current pause period is "
-                               + discoveryBatchPausePeriod + " pause tick is "
-                               + discoveryBatchPauseTicks + ".";
+        String out = "Please enter pause period less than " + discoveryBatchRestartTicks + ". Current pause period is "
+                + discoveryBatchPausePeriod + " ticks, pause at " + discoveryBatchPauseTicks + " ticks, "
+                + discoveryTimerTick / 1000 + " sec per tick.";
 
         if (val != null) {
             try {
                 int pause = Integer.parseInt(val);
                 if (pause < discoveryBatchRestartTicks) {
-                       discoveryBatchPausePeriod = pause;
-                    discoveryBatchPauseTicks = discoveryBatchRestartTicks - discoveryBatchPausePeriod;
+                    discoveryBatchPausePeriod = pause;
+                    discoveryBatchPauseTicks = getDiscoveryPauseInterval();
                     return;
                 }
             } catch (Exception e) {
@@ -1113,20 +1266,27 @@ public class DiscoveryService implements IInventoryShimExternalListener,
 
     public void _sdi(CommandInterpreter ci) {
         String val = ci.nextArgument();
-        String out = "Please enter discovery interval greater than "
-                               + discoveryBatchPausePeriod + ". Current value is "
-                               + discoveryBatchRestartTicks + ".";
+        String out = "Please enter discovery interval in ticks. Current value is " + discoveryBatchRestartTicks + " ticks, "
+                + discoveryTimerTick / 1000 + " sec per tick.";
 
         if (val != null) {
-               try {
-                       int restart = Integer.parseInt(val);        
-                   if (restart > discoveryBatchPausePeriod) {
-                       discoveryBatchRestartTicks = restart;
-                       discoveryBatchPauseTicks = discoveryBatchRestartTicks - discoveryBatchPausePeriod;
-                       return;
-                   }
-               } catch (Exception e) {
-               }
+            try {
+                int ticks;
+                Set<NodeConnector> monitorSet = holdTime.keySet();
+                if (monitorSet != null) {
+                    for (NodeConnector nodeConnector : monitorSet) {
+                        holdTime.put(nodeConnector, 0);
+                    }
+                }
+
+                ticks = Integer.parseInt(val);
+                DiscoveryPeriod.INTERVAL.setTick(ticks);
+                discoveryBatchRestartTicks = getDiscoveryInterval();
+                discoveryBatchPauseTicks = getDiscoveryPauseInterval();
+                discoveryTimeoutTicks = getDiscoveryTimeout();
+                return;
+            } catch (Exception e) {
+            }
         }
         ci.println(out);
     }
@@ -1134,8 +1294,7 @@ public class DiscoveryService implements IInventoryShimExternalListener,
     public void _sports(CommandInterpreter ci) {
         String val = ci.nextArgument();
         if (val == null) {
-            ci.println("Please enter max ports per batch. Current value is "
-                    + discoveryBatchMaxPorts);
+            ci.println("Please enter max ports per batch. Current value is " + discoveryBatchMaxPorts);
             return;
         }
         try {
@@ -1146,40 +1305,6 @@ public class DiscoveryService implements IInventoryShimExternalListener,
         return;
     }
 
-    public void _sretry(CommandInterpreter ci) {
-        String val = ci.nextArgument();
-        if (val == null) {
-            ci.println("Please enter number of retries. Current value is "
-                    + discoveryRetry);
-            return;
-        }
-        try {
-            discoveryRetry = Integer.parseInt(val);
-        } catch (Exception e) {
-            ci.println("Please enter a valid number");
-        }
-        return;
-    }
-
-    public void _stm(CommandInterpreter ci) {
-        String val = ci.nextArgument();
-        String out = "Please enter timeout tick value less than "
-                + discoveryBatchRestartTicks + ". Current value is "
-                + discoveryTimeoutTicks;
-        if (val != null) {
-            try {
-                int timeout = Integer.parseInt(val);
-                if (timeout < discoveryBatchRestartTicks) {
-                    discoveryTimeoutTicks = timeout;
-                    return;
-                }
-            } catch (Exception e) {
-            }
-        }
-
-        ci.println(out);
-    }
-
     public void _addsw(CommandInterpreter ci) {
         String val = ci.nextArgument();
         Long sid;
@@ -1241,8 +1366,7 @@ public class DiscoveryService implements IInventoryShimExternalListener,
     }
 
     @Override
-    public void updateNodeConnector(NodeConnector nodeConnector,
-            UpdateType type, Set<Property> props) {
+    public void updateNodeConnector(NodeConnector nodeConnector, UpdateType type, Set<Property> props) {
         Config config = null;
         State state = null;
         boolean enabled = false;
@@ -1254,8 +1378,7 @@ public class DiscoveryService implements IInventoryShimExternalListener,
                 state = (State) prop;
             }
         }
-        enabled = ((config != null) && (config.getValue() == Config.ADMIN_UP)
-                && (state != null) && (state.getValue() == State.EDGE_UP));
+        enabled = ((config != null) && (config.getValue() == Config.ADMIN_UP) && (state != null) && (state.getValue() == State.EDGE_UP));
 
         switch (type) {
         case ADDED:
@@ -1285,22 +1408,21 @@ public class DiscoveryService implements IInventoryShimExternalListener,
     }
 
     public void addNode(Node node, Set<Property> props) {
-        if (node == null)
+        if (node == null) {
             return;
+        }
 
         addDiscovery(node);
     }
 
     public void removeNode(Node node) {
-        if (node == null)
+        if (node == null) {
             return;
+        }
 
         removeDiscovery(node);
     }
 
-    public void updateNode(Node node, Set<Property> props) {
-    }
-
     void setController(IController s) {
         this.controller = s;
     }
@@ -1311,12 +1433,12 @@ public class DiscoveryService implements IInventoryShimExternalListener,
         }
     }
 
-    public void setPluginInInventoryService(IPluginInInventoryService service) {
-        this.pluginInInventoryService = service;
+    public void setInventoryProvider(IInventoryProvider service) {
+        this.inventoryProvider = service;
     }
 
-    public void unsetPluginInInventoryService(IPluginInInventoryService service) {
-        this.pluginInInventoryService = null;
+    public void unsetInventoryProvider(IInventoryProvider service) {
+        this.inventoryProvider = null;
     }
 
     public void setIDataPacketMux(IDataPacketMux service) {
@@ -1329,30 +1451,43 @@ public class DiscoveryService implements IInventoryShimExternalListener,
         }
     }
 
-    void setDiscoveryService(IDiscoveryService s) {
-        this.discoveryService = s;
+    void setDiscoveryListener(IDiscoveryListener s) {
+        this.discoveryListener = s;
+    }
+
+    void unsetDiscoveryListener(IDiscoveryListener s) {
+        if (this.discoveryListener == s) {
+            this.discoveryListener = null;
+        }
+    }
+
+    void setIPluginOutConnectionService(IPluginOutConnectionService s) {
+        connectionOutService = s;
     }
 
-    void unsetDiscoveryService(IDiscoveryService s) {
-        if (this.discoveryService == s) {
-            this.discoveryService = null;
+    void unsetIPluginOutConnectionService(IPluginOutConnectionService s) {
+        if (connectionOutService == s) {
+            connectionOutService = null;
         }
     }
 
     private void initDiscoveryPacket() {
         // Create LLDP ChassisID TLV
         chassisIdTlv = new LLDPTLV();
-        chassisIdTlv.setType((byte) LLDPTLV.TLVType.ChassisID.getValue());
+        chassisIdTlv.setType(LLDPTLV.TLVType.ChassisID.getValue());
+
+        // Create LLDP SystemName TLV
+        systemNameTlv = new LLDPTLV();
+        systemNameTlv.setType(LLDPTLV.TLVType.SystemName.getValue());
 
         // Create LLDP PortID TLV
         portIdTlv = new LLDPTLV();
-        portIdTlv.setType((byte) LLDPTLV.TLVType.PortID.getValue());
+        portIdTlv.setType(LLDPTLV.TLVType.PortID.getValue());
 
         // Create LLDP TTL TLV
-        byte[] ttl = new byte[] { (byte) 120 };
+        byte[] ttl = new byte[] { (byte) 0, (byte) 120 };
         ttlTlv = new LLDPTLV();
-        ttlTlv.setType((byte) LLDPTLV.TLVType.TTL.getValue()).setLength(
-                (short) ttl.length).setValue(ttl);
+        ttlTlv.setType(LLDPTLV.TLVType.TTL.getValue()).setLength((short) ttl.length).setValue(ttl);
 
         customTlv = new LLDPTLV();
     }
@@ -1369,11 +1504,21 @@ public class DiscoveryService implements IInventoryShimExternalListener,
 
         readyListHi = new CopyOnWriteArrayList<NodeConnector>();
         readyListLo = new CopyOnWriteArrayList<NodeConnector>();
-        waitingList = new CopyOnWriteArrayList<NodeConnector>();
-        pendingMap = new ConcurrentHashMap<NodeConnector, Integer>();
+        stagingList = new CopyOnWriteArrayList<NodeConnector>();
+        holdTime = new ConcurrentHashMap<NodeConnector, Integer>();
+        elapsedTime = new ConcurrentHashMap<NodeConnector, Integer>();
         edgeMap = new ConcurrentHashMap<NodeConnector, Edge>();
         agingMap = new ConcurrentHashMap<NodeConnector, Integer>();
         prodMap = new ConcurrentHashMap<NodeConnector, Edge>();
+        discoverySnoopingDisableList = new CopyOnWriteArrayList<NodeConnector>();
+
+        discoveryBatchRestartTicks = getDiscoveryInterval();
+        discoveryBatchPauseTicks = getDiscoveryPauseInterval();
+        discoveryTimeoutTicks = getDiscoveryTimeout();
+        discoveryThresholdTicks = getDiscoveryThreshold();
+        discoveryAgeoutTicks = getDiscoveryAgeout();
+        discoveryConsistencyCheckTickCount = discoveryBatchPauseTicks;
+        discoveryBatchMaxPorts = getDiscoveryBatchMaxPorts();
 
         discoveryTimer = new Timer("DiscoveryService");
         discoveryTimerTask = new DiscoveryTimerTask();
@@ -1395,8 +1540,8 @@ public class DiscoveryService implements IInventoryShimExternalListener,
         transmitQ = null;
         readyListHi = null;
         readyListLo = null;
-        waitingList = null;
-        pendingMap = null;
+        stagingList = null;
+        holdTime = null;
         edgeMap = null;
         agingMap = null;
         prodMap = null;
@@ -1411,14 +1556,12 @@ public class DiscoveryService implements IInventoryShimExternalListener,
      *
      */
     void start() {
-        discoveryTimer.schedule(discoveryTimerTask, discoveryTimerTick,
-                discoveryTimerTick);
+        discoveryTimer.schedule(discoveryTimerTask, discoveryTimerTick, discoveryTimerTick);
         transmitThread.start();
     }
 
     /**
-     * Function called after registering the
-     * service in OSGi service registry.
+     * Function called after registering the service in OSGi service registry.
      */
     void started() {
         /* get a snapshot of all the existing switches */
@@ -1438,21 +1581,19 @@ public class DiscoveryService implements IInventoryShimExternalListener,
     }
 
     @Override
-    public void tagUpdated(String containerName, Node n, short oldTag,
-            short newTag, UpdateType t) {
+    public void tagUpdated(String containerName, Node n, short oldTag, short newTag, UpdateType t) {
     }
 
     @Override
-    public void containerFlowUpdated(String containerName,
-            ContainerFlow previousFlow, ContainerFlow currentFlow, UpdateType t) {
+    public void containerFlowUpdated(String containerName, ContainerFlow previousFlow, ContainerFlow currentFlow,
+            UpdateType t) {
     }
 
     @Override
-    public void nodeConnectorUpdated(String containerName, NodeConnector p,
-            UpdateType t) {
+    public void nodeConnectorUpdated(String containerName, NodeConnector p, UpdateType t) {
         switch (t) {
         case ADDED:
-            moreToReadyListHi(p);
+            moveToReadyListHi(p);
             break;
         default:
             break;
@@ -1463,16 +1604,112 @@ public class DiscoveryService implements IInventoryShimExternalListener,
     public void containerModeUpdated(UpdateType t) {
         // do nothing
     }
-    
-    private byte[] getSouceMACFromNodeID(String nodeId) {        
+
+    private byte[] getSourceMACFromNodeID(String nodeId) {
         byte[] cid = HexEncode.bytesFromHexString(nodeId);
         byte[] sourceMac = new byte[6];
         int pos = cid.length - sourceMac.length;
 
         if (pos >= 0) {
-               System.arraycopy(cid, pos, sourceMac, 0, sourceMac.length);
+            System.arraycopy(cid, pos, sourceMac, 0, sourceMac.length);
         }
-        
+
         return sourceMac;
     }
+
+    private int getDiscoveryTicks(DiscoveryPeriod dp, String val) {
+        if (dp == null) {
+            return 0;
+        }
+
+        if (val != null) {
+            try {
+                dp.setTime(Integer.parseInt(val));
+            } catch (Exception e) {
+            }
+        }
+
+        return dp.getTick();
+    }
+
+    /**
+     * This method returns the interval which determines how often the discovery
+     * packets will be sent.
+     *
+     * @return The discovery interval in ticks
+     */
+    private int getDiscoveryInterval() {
+        String intvl = System.getProperty("of.discoveryInterval");
+        return getDiscoveryTicks(DiscoveryPeriod.INTERVAL, intvl);
+    }
+
+    /**
+     * This method returns the timeout value in receiving subsequent discovery packets on a port.
+     *
+     * @return The discovery timeout in ticks
+     */
+    private int getDiscoveryTimeout() {
+        String val = System.getProperty("of.discoveryTimeoutMultiple");
+        int multiple = 2;
+
+        if (val != null) {
+            try {
+                multiple = Integer.parseInt(val);
+            } catch (Exception e) {
+            }
+        }
+        return getDiscoveryInterval() * multiple + 3;
+    }
+
+    /**
+     * This method returns the user configurable threshold value
+     *
+     * @return The discovery threshold value in ticks
+     */
+    private int getDiscoveryThreshold() {
+        String val = System.getProperty("of.discoveryThreshold");
+        return getDiscoveryTicks(DiscoveryPeriod.THRESHOLD, val);
+    }
+
+    /**
+     * This method returns the discovery entry aging time in ticks.
+     *
+     * @return The aging time in ticks
+     */
+    private int getDiscoveryAgeout() {
+        return getDiscoveryTicks(DiscoveryPeriod.AGEOUT, null);
+    }
+
+    /**
+     * This method returns the pause interval
+     *
+     * @return The pause interval in ticks
+     */
+    private int getDiscoveryPauseInterval() {
+        if (discoveryBatchRestartTicks > discoveryBatchPausePeriod) {
+            return discoveryBatchRestartTicks - discoveryBatchPausePeriod;
+        } else {
+            return discoveryBatchRestartTicks - 1;
+        }
+    }
+
+    /**
+     * This method returns the user configurable maximum number of ports handled
+     * in one discovery batch.
+     *
+     * @return The maximum number of ports
+     */
+    private int getDiscoveryBatchMaxPorts() {
+        String val = System.getProperty("of.discoveryBatchMaxPorts");
+        int ports = 512;
+
+        if (val != null) {
+            try {
+                ports = Integer.parseInt(val);
+            } catch (Exception e) {
+            }
+        }
+        return ports;
+    }
+
 }