diff --git a/drivers/default/src/main/java/org/onosproject/driver/pipeline/CpqdOfdpa2Pipeline.java b/drivers/default/src/main/java/org/onosproject/driver/pipeline/CpqdOfdpa2Pipeline.java
index ad53d71..ff2d720 100644
--- a/drivers/default/src/main/java/org/onosproject/driver/pipeline/CpqdOfdpa2Pipeline.java
+++ b/drivers/default/src/main/java/org/onosproject/driver/pipeline/CpqdOfdpa2Pipeline.java
@@ -238,8 +238,8 @@
     }
 
     /*
-     * Cpqd emulation does not require the non-OF standard rules for
-     * matching untagged packets.
+     * Cpqd emulation does not require the non OF-standard rules for
+     * matching untagged packets that ofdpa uses.
      *
      * (non-Javadoc)
      * @see org.onosproject.driver.pipeline.OFDPA2Pipeline#processVlanIdFilter
@@ -510,7 +510,8 @@
                 // we only need the top level group's key to point the flow to it
                 Group group = groupService.getGroup(deviceId, gkeys.get(0).peekFirst());
                 if (group == null) {
-                    log.warn("The group left!");
+                    log.warn("Group with key:{} for next-id:{} not found in dev:{}",
+                             gkeys.get(0).peekFirst(), fwd.nextId(), deviceId);
                     fail(fwd, ObjectiveError.GROUPMISSING);
                     return Collections.emptySet();
                 }
@@ -549,7 +550,6 @@
             flowRuleCollection.add(rule.build());
             log.debug("Default rule 0.0.0.0/0 is being installed two rules");
         }
-
         return flowRuleCollection;
     }
 
diff --git a/drivers/default/src/main/java/org/onosproject/driver/pipeline/CpqdOfdpa3Pipeline.java b/drivers/default/src/main/java/org/onosproject/driver/pipeline/CpqdOfdpa3Pipeline.java
deleted file mode 100644
index 9cf05d2..0000000
--- a/drivers/default/src/main/java/org/onosproject/driver/pipeline/CpqdOfdpa3Pipeline.java
+++ /dev/null
@@ -1,64 +0,0 @@
-/*
- * Copyright 2016-present Open Networking Laboratory
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.onosproject.driver.pipeline;
-
-import org.onosproject.core.CoreService;
-import org.onosproject.net.DeviceId;
-import org.onosproject.net.behaviour.PipelinerContext;
-import org.onosproject.net.device.DeviceService;
-import org.onosproject.net.flow.FlowRule;
-import org.onosproject.net.flow.FlowRuleService;
-import org.onosproject.net.flowobjective.ForwardingObjective;
-import org.onosproject.net.group.GroupService;
-
-import java.util.Collection;
-
-/**
- * Driver for software switch emulation of the OFDPA 3.0 pipeline.
- * The software switch is the CPqD OF 1.3 switch. Unfortunately the CPqD switch
- * does not handle vlan tags and mpls labels simultaneously, which requires us
- * to do some workarounds in the driver. This driver is meant for the use of
- * the cpqd switch when MPLS is required. As a result this driver works only
- * on incoming untagged packets.
- */
-public class CpqdOfdpa3Pipeline extends CpqdOfdpa2Pipeline {
-    @Override
-    public void init(DeviceId deviceId, PipelinerContext context) {
-        this.deviceId = deviceId;
-
-        // Initialize OFDPA group handler
-        groupHandler = new Ofdpa3GroupHandler();
-        groupHandler.init(deviceId, context);
-
-        serviceDirectory = context.directory();
-        coreService = serviceDirectory.get(CoreService.class);
-        flowRuleService = serviceDirectory.get(FlowRuleService.class);
-        groupService = serviceDirectory.get(GroupService.class);
-        flowObjectiveStore = context.store();
-        deviceService = serviceDirectory.get(DeviceService.class);
-
-        driverId = coreService.registerApplication(
-                "org.onosproject.driver.CpqdOfdpa3Pipeline");
-
-        initializePipeline();
-    }
-
-    @Override
-    protected Collection<FlowRule> processEthTypeSpecific(ForwardingObjective fwd) {
-        return processEthTypeSpecificInternal(fwd, true, ACL_TABLE);
-    }
-}
diff --git a/drivers/default/src/main/java/org/onosproject/driver/pipeline/Ofdpa2GroupHandler.java b/drivers/default/src/main/java/org/onosproject/driver/pipeline/Ofdpa2GroupHandler.java
index 0098d01..7d85f19 100644
--- a/drivers/default/src/main/java/org/onosproject/driver/pipeline/Ofdpa2GroupHandler.java
+++ b/drivers/default/src/main/java/org/onosproject/driver/pipeline/Ofdpa2GroupHandler.java
@@ -64,6 +64,7 @@
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Deque;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Objects;
 import java.util.Set;
@@ -125,7 +126,8 @@
 
     // local store for pending bucketAdds - by design there can only be one
     // pending bucket for a group
-    protected ConcurrentHashMap<Integer, NextObjective> pendingBuckets = new ConcurrentHashMap<>();
+    protected ConcurrentHashMap<Integer, NextObjective> pendingBuckets =
+            new ConcurrentHashMap<>();
 
     protected void init(DeviceId deviceId, PipelinerContext context) {
         this.deviceId = deviceId;
@@ -236,9 +238,8 @@
         Deque<GroupKey> gkeyChain = new ArrayDeque<>();
         gkeyChain.addFirst(groupInfo.innerMostGroupDesc.appCookie());
         gkeyChain.addFirst(groupInfo.nextGroupDesc.appCookie());
-        OfdpaNextGroup ofdpaGrp = new OfdpaNextGroup(
-                Collections.singletonList(gkeyChain),
-                nextObj);
+        OfdpaNextGroup ofdpaGrp =
+                new OfdpaNextGroup(Collections.singletonList(gkeyChain), nextObj);
 
         // store l3groupkey with the ofdpaNextGroup for the nextObjective that depends on it
         updatePendingNextObjective(groupInfo.nextGroupDesc.appCookie(), ofdpaGrp);
@@ -522,7 +523,8 @@
         }
     }
 
-    private List<GroupInfo> prepareL2InterfaceGroup(NextObjective nextObj, VlanId assignedVlan) {
+    private List<GroupInfo> prepareL2InterfaceGroup(NextObjective nextObj,
+                                                    VlanId assignedVlan) {
         ImmutableList.Builder<GroupInfo> groupInfoBuilder = ImmutableList.builder();
 
         // break up broadcast next objective to multiple groups
@@ -588,12 +590,14 @@
         return groupInfoBuilder.build();
     }
 
-    private void createL2FloodGroup(NextObjective nextObj, VlanId vlanId, List<GroupInfo> groupInfos) {
-        // assemble info for l2 flood group
-        // since there can be only one flood group for a vlan, its index is always the same - 0
+    private void createL2FloodGroup(NextObjective nextObj, VlanId vlanId,
+                                    List<GroupInfo> groupInfos) {
+        // assemble info for l2 flood group. Since there can be only one flood
+        // group for a vlan, its index is always the same - 0
         Integer l2floodgroupId = L2_FLOOD_TYPE | (vlanId.toShort() << 16);
         int l2floodgk = getNextAvailableIndex();
-        final GroupKey l2floodgroupkey = new DefaultGroupKey(Ofdpa2Pipeline.appKryo.serialize(l2floodgk));
+        final GroupKey l2floodgroupkey =
+                new DefaultGroupKey(Ofdpa2Pipeline.appKryo.serialize(l2floodgk));
 
         // collection of group buckets pointing to all the l2 interface groups
         List<GroupBucket> l2floodBuckets = Lists.newArrayList();
@@ -642,7 +646,8 @@
         });
     }
 
-    private void createL3MulticastGroup(NextObjective nextObj, VlanId vlanId, List<GroupInfo> groupInfos) {
+    private void createL3MulticastGroup(NextObjective nextObj, VlanId vlanId,
+                                        List<GroupInfo> groupInfos) {
         List<GroupBucket> l3McastBuckets = new ArrayList<>();
         groupInfos.forEach(groupInfo -> {
             // Points to L3 interface group if there is one.
@@ -656,8 +661,10 @@
         });
 
         int l3MulticastIndex = getNextAvailableIndex();
-        int l3MulticastGroupId = L3_MULTICAST_TYPE | vlanId.toShort() << 16 | (TYPE_VLAN_MASK & l3MulticastIndex);
-        final GroupKey l3MulticastGroupKey = new DefaultGroupKey(Ofdpa2Pipeline.appKryo.serialize(l3MulticastIndex));
+        int l3MulticastGroupId = L3_MULTICAST_TYPE |
+                vlanId.toShort() << 16 | (TYPE_VLAN_MASK & l3MulticastIndex);
+        final GroupKey l3MulticastGroupKey =
+                new DefaultGroupKey(Ofdpa2Pipeline.appKryo.serialize(l3MulticastIndex));
 
         GroupDescription l3MulticastGroupDesc = new DefaultGroupDescription(deviceId,
                 GroupDescription.Type.ALL,
@@ -891,8 +898,10 @@
 
     /**
      *  Adds a bucket to the top level group of a group-chain, and creates the chain.
+     *  Ensures that bucket being added is not a duplicate, by checking existing
+     *  buckets for the same outport.
      *
-     * @param nextObjective the next group to add a bucket to
+     * @param nextObjective the bucket information for a next group
      * @param next the representation of the existing group-chain for this next objective
      */
     protected void addBucketToGroup(NextObjective nextObjective, NextGroup next) {
@@ -905,6 +914,30 @@
             log.warn("Only one bucket can be added at a time");
             return;
         }
+        // first check to see if bucket being added is not a duplicate of an
+        // existing bucket. If it is for an existing outport, then its a duplicate.
+        Set<PortNumber> existingOutPorts = new HashSet<>();
+        List<Deque<GroupKey>> allActiveKeys = Ofdpa2Pipeline.appKryo.deserialize(next.data());
+        for (Deque<GroupKey> gkeys : allActiveKeys) {
+            // get the last group for the outport
+            Group glast = groupService.getGroup(deviceId, gkeys.peekLast());
+            if (glast != null && !glast.buckets().buckets().isEmpty()) {
+                PortNumber op = readOutPortFromTreatment(
+                                    glast.buckets().buckets().get(0).treatment());
+                if (op != null) {
+                    existingOutPorts.add(op);
+                }
+            }
+        }
+        // only a single bucket being added
+        TrafficTreatment tt = nextObjective.next().iterator().next();
+        PortNumber newport = readOutPortFromTreatment(tt);
+        if (existingOutPorts.contains(newport)) {
+            log.warn("Attempt to add bucket for existing outport:{} in dev:{} for next:{}",
+                     newport, deviceId, nextObjective.id());
+            return;
+        }
+
         // storage for all group keys in the chain of groups created
         List<Deque<GroupKey>> allGroupKeys = new ArrayList<>();
         List<GroupInfo> unsentGroups = new ArrayList<>();
@@ -916,12 +949,28 @@
         ttb.group(new DefaultGroupId(gi.nextGroupDesc.givenGroupId()));
         GroupBucket sbucket = DefaultGroupBucket.createSelectGroupBucket(ttb.build());
 
-        // recreate the original L3 ECMP group id and description
-        int l3ecmpGroupId = L3_ECMP_TYPE | nextObjective.id() << 12;
-        GroupKey l3ecmpGroupKey = new DefaultGroupKey(Ofdpa2Pipeline.appKryo.serialize(l3ecmpGroupId));
+        // retrieve the original L3 ECMP group id and description from the first
+        // element in any deque.
+        GroupKey l3ecmpGroupKey = null;
+        if (!allActiveKeys.isEmpty()) {
+            l3ecmpGroupKey = allActiveKeys.get(0).peekFirst();
+        } else {
+            log.warn("Could not determine top level group while trying to"
+                    + "add bucket for port:{} in dev:{} for next:{}",
+                    deviceId, nextObjective.id(), newport);
+            return;
+        }
+        Group l3ecmpGroup = groupService.getGroup(deviceId, l3ecmpGroupKey);
+        if (l3ecmpGroup == null) {
+            log.warn("Could not find l3 ecmp group while trying to add bucket"
+                    + "for port:{} in dev:{} for next:{}", deviceId,
+                    nextObjective.id(), newport);
+            return;
+        }
+        int l3ecmpGroupId = l3ecmpGroup.id().id();
 
         // Although GroupDescriptions are not necessary for adding buckets to
-        // existing groups, we use one in the GroupChainElem. When the latter is
+        // existing groups, we still use one in the GroupChainElem. When the latter is
         // processed, the info will be extracted for the bucketAdd call to groupService
         GroupDescription l3ecmpGroupDesc =
                 new DefaultGroupDescription(
@@ -934,14 +983,16 @@
         GroupChainElem l3ecmpGce = new GroupChainElem(l3ecmpGroupDesc, 1, true);
 
         // update original NextGroup with new bucket-chain
-        // don't need to update pendingNextObjectives -- group already exists
+        // If active keys shows only the top-level group without a chain of groups,
+        // then it represents an empty group. Update by replacing empty chain.
         Deque<GroupKey> newBucketChain = allGroupKeys.get(0);
         newBucketChain.addFirst(l3ecmpGroupKey);
-        List<Deque<GroupKey>> allOriginalKeys = Ofdpa2Pipeline.appKryo.deserialize(next.data());
-        allOriginalKeys.add(newBucketChain);
-        flowObjectiveStore.putNextGroup(nextObjective.id(),
-                new OfdpaNextGroup(allOriginalKeys, nextObjective));
-
+        if (allActiveKeys.size() == 1 && allActiveKeys.get(0).size() == 1) {
+            allActiveKeys.clear();
+        }
+        allActiveKeys.add(newBucketChain);
+        updatePendingNextObjective(l3ecmpGroupKey,
+                                   new OfdpaNextGroup(allActiveKeys, nextObjective));
         log.debug("Adding to L3ECMP: device:{} gid:{} gkey:{} nextId:{}",
                 deviceId, Integer.toHexString(l3ecmpGroupId),
                 l3ecmpGroupKey, nextObjective.id());
@@ -958,7 +1009,7 @@
      * not remove the groups in a group-chain pointed to by this bucket, as they
      * may be in use (referenced by other groups) elsewhere.
      *
-     * @param nextObjective the next group to remove a bucket from
+     * @param nextObjective the bucket information for a next group
      * @param next the representation of the existing group-chain for this next objective
      */
     protected void removeBucketFromGroup(NextObjective nextObjective, NextGroup next) {
@@ -971,41 +1022,29 @@
         TrafficTreatment treatment = treatments.iterator().next();
         // find the bucket to remove by noting the outport, and figuring out the
         // top-level group in the group-chain that indirectly references the port
-        PortNumber outport = null;
-        for (Instruction ins : treatment.allInstructions()) {
-            if (ins instanceof Instructions.OutputInstruction) {
-                outport = ((Instructions.OutputInstruction) ins).port();
-                break;
-            }
-        }
-        if (outport == null) {
-            log.error("next objective {} has no outport", nextObjective.id());
+        PortNumber portToRemove = readOutPortFromTreatment(treatment);
+        if (portToRemove == null) {
+            log.warn("next objective {} has no outport.. cannot remove bucket"
+                    + "from group in dev: {}", nextObjective.id(), deviceId);
             return;
         }
 
-        List<Deque<GroupKey>> allgkeys = Ofdpa2Pipeline.appKryo.deserialize(next.data());
+        List<Deque<GroupKey>> allActiveKeys = Ofdpa2Pipeline.appKryo.deserialize(next.data());
         Deque<GroupKey> foundChain = null;
         int index = 0;
-        for (Deque<GroupKey> gkeys : allgkeys) {
+        for (Deque<GroupKey> gkeys : allActiveKeys) {
+            // last group in group chain should have a single bucket pointing to port
             GroupKey groupWithPort = gkeys.peekLast();
             Group group = groupService.getGroup(deviceId, groupWithPort);
             if (group == null) {
-                log.warn("Inconsistent group chain");
+                log.warn("Inconsistent group chain found when removing bucket"
+                        + "for next:{} in dev:{}", nextObjective.id(), deviceId);
                 continue;
             }
-            // last group in group chain should have a single bucket pointing to port
-            List<Instruction> lastIns = group.buckets().buckets().iterator()
-                    .next().treatment().allInstructions();
-            for (Instruction i : lastIns) {
-                if (i instanceof Instructions.OutputInstruction) {
-                    PortNumber lastport = ((Instructions.OutputInstruction) i).port();
-                    if (lastport.equals(outport)) {
-                        foundChain = gkeys;
-                        break;
-                    }
-                }
-            }
-            if (foundChain != null) {
+            PortNumber pout = readOutPortFromTreatment(
+                                  group.buckets().buckets().get(0).treatment());
+            if (pout.equals(portToRemove)) {
+                foundChain = gkeys;
                 break;
             }
             index++;
@@ -1030,15 +1069,24 @@
                             .build());
             GroupBuckets removeBuckets = new GroupBuckets(Collections
                     .singletonList(bucket));
-            log.debug("Removing buckets from group id {} for next id {} in device {}",
-                    modGroup.id(), nextObjective.id(), deviceId);
+            log.debug("Removing buckets from group id 0x{} pointing to group id 0x{}"
+                    + "for next id {} in device {}", Integer.toHexString(modGroup.id().id()),
+                    Integer.toHexString(pointedGroup.id().id()), nextObjective.id(), deviceId);
             groupService.removeBucketsFromGroup(deviceId, modGroupKey,
                     removeBuckets, modGroupKey,
                     nextObjective.appId());
-            //update store
-            allgkeys.remove(index);
+            // update store
+            // If the bucket removed was the last bucket in the group, then
+            // retain an entry for the top level group which still exists.
+            if (allActiveKeys.size() == 1) {
+                ArrayDeque<GroupKey> top = new ArrayDeque<>();
+                top.add(modGroupKey);
+                allActiveKeys.add(top);
+            }
+            allActiveKeys.remove(index);
             flowObjectiveStore.putNextGroup(nextObjective.id(),
-                    new OfdpaNextGroup(allgkeys, nextObjective));
+                                            new OfdpaNextGroup(allActiveKeys,
+                                                               nextObjective));
         } else {
             log.warn("Could not find appropriate group-chain for removing bucket"
                     + " for next id {} in dev:{}", nextObjective.id(), deviceId);
@@ -1054,13 +1102,13 @@
      *             this next objective
      */
     protected void removeGroup(NextObjective nextObjective, NextGroup next) {
-        List<Deque<GroupKey>> allgkeys = Ofdpa2Pipeline.appKryo.deserialize(next.data());
+        List<Deque<GroupKey>> allActiveKeys = Ofdpa2Pipeline.appKryo.deserialize(next.data());
 
-        List<GroupKey> groupKeys = allgkeys.stream()
+        List<GroupKey> groupKeys = allActiveKeys.stream()
                 .map(Deque::getFirst).collect(Collectors.toList());
         pendingRemoveNextObjectives.put(nextObjective, groupKeys);
 
-        allgkeys.forEach(groupChain -> groupChain.forEach(groupKey ->
+        allActiveKeys.forEach(groupChain -> groupChain.forEach(groupKey ->
                 groupService.removeGroup(deviceId, groupKey, nextObjective.appId())));
         flowObjectiveStore.removeNextGroup(nextObjective.id());
     }
@@ -1207,6 +1255,21 @@
     }
 
     /**
+     * Returns the outport in a traffic treatment.
+     *
+     * @param tt the treatment
+     * @return the PortNumber for the outport or null
+     */
+    protected static PortNumber readOutPortFromTreatment(TrafficTreatment tt) {
+        for (Instruction ins : tt.allInstructions()) {
+            if (ins.type() == Instruction.Type.OUTPUT) {
+                return ((Instructions.OutputInstruction) ins).port();
+            }
+        }
+        return null;
+    }
+
+    /**
      * Returns a hash as the L2 Interface Group Key.
      *
      * Keep the lower 6-bit for port since port number usually smaller than 64.
@@ -1264,7 +1327,7 @@
      * top level ECMP group, while every other element represents a unique groupKey.
      * <p>
      * Also includes information about the next objective that
-     * resulted in this group-chain.
+     * resulted in these group-chains.
      *
      */
     protected class OfdpaNextGroup implements NextGroup {
@@ -1272,18 +1335,18 @@
         private final List<Deque<GroupKey>> gkeys;
 
         public OfdpaNextGroup(List<Deque<GroupKey>> gkeys, NextObjective nextObj) {
-            this.gkeys = gkeys;
             this.nextObj = nextObj;
-        }
-
-        public List<Deque<GroupKey>> groupKey() {
-            return gkeys;
+            this.gkeys = gkeys;
         }
 
         public NextObjective nextObjective() {
             return nextObj;
         }
 
+        public List<Deque<GroupKey>> groupKeys() {
+            return gkeys;
+        }
+
         @Override
         public byte[] data() {
             return Ofdpa2Pipeline.appKryo.serialize(gkeys);
@@ -1295,7 +1358,7 @@
      * Stores enough information to create a Group Description to add the group
      * to the switch by requesting the Group Service. Objects instantiating this
      * class are meant to be temporary and live as long as it is needed to wait for
-     * preceding groups in the group chain to be created.
+     * referenced groups in the group chain to be created.
      */
     protected class GroupChainElem {
         private GroupDescription groupDescription;
@@ -1310,7 +1373,7 @@
         }
 
         /**
-         * This methods atomically decrements the counter for the number of
+         * This method atomically decrements the counter for the number of
          * groups this GroupChainElement is waiting on, for notifications from
          * the Group Service. When this method returns a value of 0, this
          * GroupChainElement is ready to be processed.
diff --git a/drivers/default/src/main/java/org/onosproject/driver/pipeline/Ofdpa2Pipeline.java b/drivers/default/src/main/java/org/onosproject/driver/pipeline/Ofdpa2Pipeline.java
index a72eea1..4600eb8 100644
--- a/drivers/default/src/main/java/org/onosproject/driver/pipeline/Ofdpa2Pipeline.java
+++ b/drivers/default/src/main/java/org/onosproject/driver/pipeline/Ofdpa2Pipeline.java
@@ -15,6 +15,8 @@
  */
 package org.onosproject.driver.pipeline;
 
+import static java.util.concurrent.Executors.newScheduledThreadPool;
+import static org.onlab.util.Tools.groupedThreads;
 import static org.slf4j.LoggerFactory.getLogger;
 
 import java.util.ArrayDeque;
@@ -26,6 +28,8 @@
 import java.util.Objects;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
@@ -131,6 +135,11 @@
 
     protected Set<IPCriterion> sentIpFilters = Collections.newSetFromMap(
                                                new ConcurrentHashMap<>());
+    // flows installations to be retried
+    protected ScheduledExecutorService executorService
+        = newScheduledThreadPool(5, groupedThreads("OfdpaPipeliner", "retry-%d", log));
+    protected static final int MAX_RETRY_ATTEMPTS = 10;
+    protected static final int RETRY_MS = 1000;
 
     @Override
     public void init(DeviceId deviceId, PipelinerContext context) {
@@ -181,30 +190,33 @@
 
     @Override
     public void forward(ForwardingObjective fwd) {
-        Collection<FlowRule> rules;
-        FlowRuleOperations.Builder flowOpsBuilder = FlowRuleOperations.builder();
-
-        rules = processForward(fwd);
+        Collection<FlowRule> rules = processForward(fwd);
         if (rules == null || rules.isEmpty()) {
             // Assumes fail message has already been generated to the objective
             // context. Returning here prevents spurious pass message to be
             // generated by FlowRule service for empty flowOps.
             return;
         }
+        sendForward(fwd, rules);
+    }
+
+    protected void sendForward(ForwardingObjective fwd, Collection<FlowRule> rules) {
+        FlowRuleOperations.Builder flowOpsBuilder = FlowRuleOperations.builder();
         switch (fwd.op()) {
-            case ADD:
-                rules.stream()
-                        .filter(Objects::nonNull)
-                        .forEach(flowOpsBuilder::add);
-                break;
-            case REMOVE:
-                rules.stream()
-                        .filter(Objects::nonNull)
-                        .forEach(flowOpsBuilder::remove);
-                break;
-            default:
-                fail(fwd, ObjectiveError.UNKNOWN);
-                log.warn("Unknown forwarding type {}", fwd.op());
+        case ADD:
+            rules.stream()
+            .filter(Objects::nonNull)
+            .forEach(flowOpsBuilder::add);
+            log.info("Applying a flow rule to sw:{}", deviceId);
+            break;
+        case REMOVE:
+            rules.stream()
+            .filter(Objects::nonNull)
+            .forEach(flowOpsBuilder::remove);
+            break;
+        default:
+            fail(fwd, ObjectiveError.UNKNOWN);
+            log.warn("Unknown forwarding type {}", fwd.op());
         }
 
         flowRuleService.apply(flowOpsBuilder.build(new FlowRuleOperationsContext() {
@@ -802,24 +814,6 @@
         }
     }
 
-    private boolean isSupportedEthTypeObjective(ForwardingObjective fwd) {
-        TrafficSelector selector = fwd.selector();
-        EthTypeCriterion ethType = (EthTypeCriterion) selector
-                .getCriterion(Criterion.Type.ETH_TYPE);
-        return !((ethType == null) ||
-                ((ethType.ethType().toShort() != Ethernet.TYPE_IPV4) &&
-                        (ethType.ethType().toShort() != Ethernet.MPLS_UNICAST)));
-    }
-
-    private boolean isSupportedEthDstObjective(ForwardingObjective fwd) {
-        TrafficSelector selector = fwd.selector();
-        EthCriterion ethDst = (EthCriterion) selector
-                .getCriterion(Criterion.Type.ETH_DST);
-        VlanIdCriterion vlanId = (VlanIdCriterion) selector
-                .getCriterion(Criterion.Type.VLAN_VID);
-        return !(ethDst == null && vlanId == null);
-    }
-
     /**
      * Handles forwarding rules to the IP and MPLS tables.
      *
@@ -850,6 +844,7 @@
                 (EthTypeCriterion) selector.getCriterion(Criterion.Type.ETH_TYPE);
         boolean defaultRule = false;
         boolean popMpls = false;
+        boolean emptyGroup = false;
         int forTableId;
         TrafficSelector.Builder filteredSelector = DefaultTrafficSelector.builder();
         TrafficTreatment.Builder tb = DefaultTrafficTreatment.builder();
@@ -967,6 +962,12 @@
                     return Collections.emptySet();
                 }
                 tb.deferred().group(group.id());
+                // check if group is empty
+                if (gkeys.size() == 1 && gkeys.get(0).size() == 1) {
+                    log.warn("Found empty group 0x{} in dev:{} .. will retry fwd:{}",
+                             Integer.toHexString(group.id().id()), deviceId, fwd.id());
+                    emptyGroup = true;
+                }
             } else {
                 log.warn("Cannot find group for nextId:{} in dev:{}. Aborting fwd:{}",
                          fwd.nextId(), deviceId, fwd.id());
@@ -1016,7 +1017,11 @@
             flowRuleCollection.add(rule.build());
             log.debug("Default rule 0.0.0.0/0 is being installed two rules");
         }
-
+        // XXX retrying flows may be necessary due to bug CORD-554
+        if (emptyGroup) {
+            executorService.schedule(new RetryFlows(fwd, flowRuleCollection),
+                                     RETRY_MS, TimeUnit.MILLISECONDS);
+        }
         return flowRuleCollection;
     }
 
@@ -1103,6 +1108,28 @@
         return rules;
     }
 
+    //////////////////////////////////////
+    //  Helper Methods and Classes
+    //////////////////////////////////////
+
+    private boolean isSupportedEthTypeObjective(ForwardingObjective fwd) {
+        TrafficSelector selector = fwd.selector();
+        EthTypeCriterion ethType = (EthTypeCriterion) selector
+                .getCriterion(Criterion.Type.ETH_TYPE);
+        return !((ethType == null) ||
+                ((ethType.ethType().toShort() != Ethernet.TYPE_IPV4) &&
+                        (ethType.ethType().toShort() != Ethernet.MPLS_UNICAST)));
+    }
+
+    private boolean isSupportedEthDstObjective(ForwardingObjective fwd) {
+        TrafficSelector selector = fwd.selector();
+        EthCriterion ethDst = (EthCriterion) selector
+                .getCriterion(Criterion.Type.ETH_DST);
+        VlanIdCriterion vlanId = (VlanIdCriterion) selector
+                .getCriterion(Criterion.Type.VLAN_VID);
+        return !(ethDst == null && vlanId == null);
+    }
+
     protected NextGroup getGroupForNextObjective(Integer nextId) {
         NextGroup next = flowObjectiveStore.getNextGroup(nextId);
         if (next != null) {
@@ -1147,7 +1174,7 @@
             }
             // add port information for last group in group-chain
             List<Instruction> lastGroupIns = new ArrayList<Instruction>();
-            if (lastGroup != null) {
+            if (lastGroup != null && !lastGroup.buckets().buckets().isEmpty()) {
                 lastGroupIns = lastGroup.buckets().buckets().get(0)
                                     .treatment().allInstructions();
             }
@@ -1189,4 +1216,30 @@
         }
         return null;
     }
+
+    /**
+     *  Utility class that retries sending flows a fixed number of times, even if
+     *  some of the attempts are successful. Used only for forwarding objectives.
+     */
+    protected final class RetryFlows implements Runnable {
+        int attempts = MAX_RETRY_ATTEMPTS;
+        private Collection<FlowRule> retryFlows;
+        private ForwardingObjective fwd;
+
+        RetryFlows(ForwardingObjective fwd, Collection<FlowRule> retryFlows) {
+            this.fwd = fwd;
+            this.retryFlows = retryFlows;
+        }
+
+        @Override
+        public void run() {
+            log.info("RETRY FLOWS ATTEMPT# {} for fwd:{} rules:{}",
+                     MAX_RETRY_ATTEMPTS - attempts, fwd.id(), retryFlows.size());
+            sendForward(fwd, retryFlows);
+            if (--attempts > 0) {
+                executorService.schedule(this, RETRY_MS, TimeUnit.MILLISECONDS);
+            }
+        }
+    }
+
 }