diff --git a/core/api/src/main/java/org/onosproject/net/flowobjective/DefaultForwardingObjective.java b/core/api/src/main/java/org/onosproject/net/flowobjective/DefaultForwardingObjective.java
index 0abf5ab..af48180 100644
--- a/core/api/src/main/java/org/onosproject/net/flowobjective/DefaultForwardingObjective.java
+++ b/core/api/src/main/java/org/onosproject/net/flowobjective/DefaultForwardingObjective.java
@@ -16,6 +16,7 @@
 package org.onosproject.net.flowobjective;
 
 import com.google.common.annotations.Beta;
+
 import org.onosproject.core.ApplicationId;
 import org.onosproject.net.flow.TrafficSelector;
 import org.onosproject.net.flow.TrafficTreatment;
@@ -119,6 +120,53 @@
         return context;
     }
 
+    /*
+     * (non-Javadoc)
+     *
+     * @see java.lang.Object#hashCode()
+     */
+    @Override
+    public int hashCode() {
+        return Objects.hash(selector, flag, permanent,
+                            timeout, appId, priority, nextId,
+                            treatment, op);
+    }
+
+    /*
+     * (non-Javadoc)
+     *
+     * @see java.lang.Object#equals(java.lang.Object)
+     */
+    @Override
+    public boolean equals(final Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (!(obj instanceof DefaultForwardingObjective)) {
+            return false;
+        }
+        final DefaultForwardingObjective other = (DefaultForwardingObjective) obj;
+        boolean nextEq = false, treatmentEq = false;
+        if (this.selector.equals(other.selector) &&
+                this.flag == other.flag &&
+                this.permanent == other.permanent &&
+                this.timeout == other.timeout &&
+                this.appId.equals(other.appId) &&
+                this.priority == other.priority &&
+                this.op == other.op) {
+            if (this.nextId != null && other.nextId != null) {
+                nextEq = this.nextId == other.nextId;
+            }
+            if (this.treatment != null && other.treatment != null) {
+                treatmentEq = this.treatment.equals(other.treatment);
+            }
+            if (nextEq && treatmentEq) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     /**
      * Returns a new builder.
      *
diff --git a/core/api/src/main/java/org/onosproject/net/flowobjective/DefaultNextObjective.java b/core/api/src/main/java/org/onosproject/net/flowobjective/DefaultNextObjective.java
index 20e8929..4701589 100644
--- a/core/api/src/main/java/org/onosproject/net/flowobjective/DefaultNextObjective.java
+++ b/core/api/src/main/java/org/onosproject/net/flowobjective/DefaultNextObjective.java
@@ -18,6 +18,7 @@
 import com.google.common.annotations.Beta;
 import com.google.common.collect.ImmutableList;
 import org.onosproject.core.ApplicationId;
+import org.onosproject.net.flow.TrafficSelector;
 import org.onosproject.net.flow.TrafficTreatment;
 
 import java.util.Collection;
@@ -39,6 +40,7 @@
     private final Integer id;
     private final Operation op;
     private final Optional<ObjectiveContext> context;
+    private final TrafficSelector meta;
 
     private DefaultNextObjective(Builder builder) {
         this.treatments = builder.treatments;
@@ -47,6 +49,7 @@
         this.id = builder.id;
         this.op = builder.op;
         this.context = Optional.ofNullable(builder.context);
+        this.meta = builder.meta;
     }
 
     @Override
@@ -94,6 +97,11 @@
         return context;
     }
 
+    @Override
+    public TrafficSelector meta() {
+        return meta;
+    }
+
     /**
      * Returns a new builder.
      *
@@ -111,6 +119,7 @@
         private List<TrafficTreatment> treatments;
         private Operation op;
         private ObjectiveContext context;
+        private TrafficSelector meta;
 
         private final ImmutableList.Builder<TrafficTreatment> listBuilder
                 = ImmutableList.builder();
@@ -172,6 +181,12 @@
         }
 
         @Override
+        public Builder setMeta(TrafficSelector meta) {
+            this.meta = meta;
+            return this;
+        }
+
+        @Override
         public NextObjective add() {
             treatments = listBuilder.build();
             op = Operation.ADD;
@@ -218,5 +233,55 @@
 
             return new DefaultNextObjective(this);
         }
+
+        @Override
+        public NextObjective addToExisting() {
+            treatments = listBuilder.build();
+            op = Operation.ADD_TO_EXISTING;
+            checkNotNull(appId, "Must supply an application id");
+            checkNotNull(id, "id cannot be null");
+            checkNotNull(type, "The type cannot be null");
+            checkArgument(!treatments.isEmpty(), "Must have at least one treatment");
+
+            return new DefaultNextObjective(this);
+        }
+
+        @Override
+        public NextObjective removeFromExisting() {
+            treatments = listBuilder.build();
+            op = Operation.REMOVE_FROM_EXISTING;
+            checkNotNull(appId, "Must supply an application id");
+            checkNotNull(id, "id cannot be null");
+            checkNotNull(type, "The type cannot be null");
+
+            return new DefaultNextObjective(this);
+        }
+
+        @Override
+        public NextObjective addToExisting(ObjectiveContext context) {
+            treatments = listBuilder.build();
+            op = Operation.ADD_TO_EXISTING;
+            this.context = context;
+            checkNotNull(appId, "Must supply an application id");
+            checkNotNull(id, "id cannot be null");
+            checkNotNull(type, "The type cannot be null");
+            checkArgument(!treatments.isEmpty(), "Must have at least one treatment");
+
+            return new DefaultNextObjective(this);
+        }
+
+        @Override
+        public NextObjective removeFromExisting(ObjectiveContext context) {
+            treatments = listBuilder.build();
+            op = Operation.REMOVE_FROM_EXISTING;
+            this.context = context;
+            checkNotNull(appId, "Must supply an application id");
+            checkNotNull(id, "id cannot be null");
+            checkNotNull(type, "The type cannot be null");
+
+            return new DefaultNextObjective(this);
+        }
+
     }
+
 }
diff --git a/core/api/src/main/java/org/onosproject/net/flowobjective/NextObjective.java b/core/api/src/main/java/org/onosproject/net/flowobjective/NextObjective.java
index 1350d7a..08916eb 100644
--- a/core/api/src/main/java/org/onosproject/net/flowobjective/NextObjective.java
+++ b/core/api/src/main/java/org/onosproject/net/flowobjective/NextObjective.java
@@ -17,6 +17,7 @@
 
 import com.google.common.annotations.Beta;
 import org.onosproject.core.ApplicationId;
+import org.onosproject.net.flow.TrafficSelector;
 import org.onosproject.net.flow.TrafficTreatment;
 
 import java.util.Collection;
@@ -34,7 +35,7 @@
  * - Failover
  * - Simple
  *
- * These types will indicate to the driver what the intended behaviour is.
+ * These types will indicate to the driver what the intended behavior is.
  * For example, a broadcast next objective with a collection of output
  * treatments will indicate to a driver that all output actions are expected
  * to be executed simultaneously. The driver is then free to implement this
@@ -84,6 +85,16 @@
     Type type();
 
     /**
+     * Auxiliary optional information provided to the device-driver.Typically
+     * conveys information about selectors (matches) that are intended to
+     * use this Next Objective.
+     *
+     * @return a selector intended to pass meta information to the device driver.
+     *         Value may be null if no meta information is provided.
+     */
+    TrafficSelector meta();
+
+    /**
      * A next step builder.
      */
     interface Builder extends Objective.Builder {
@@ -131,6 +142,14 @@
         Builder withPriority(int priority);
 
         /**
+         * Set meta information related to this next objective.
+         *
+         * @param selector match conditions
+         * @return an objective builder
+         */
+        Builder setMeta(TrafficSelector selector);
+
+        /**
          * Builds the next objective that will be added.
          *
          * @return a next objective
@@ -162,6 +181,40 @@
          */
         NextObjective remove(ObjectiveContext context);
 
+        /**
+         * Build the next objective that will be added, with {@link Operation}
+         * ADD_TO_EXISTING.
+         *
+         * @return a next objective
+         */
+        NextObjective addToExisting();
+
+        /**
+         * Build the next objective that will be removed, with {@link Operation}
+         * REMOVE_FROM_EXISTING.
+         *
+         * @return a next objective
+         */
+        NextObjective removeFromExisting();
+
+        /**
+         * Builds the next objective that will be added, with {@link Operation}
+         * ADD_TO_EXISTING. The context will be used to notify the calling application.
+         *
+         * @param context an objective context
+         * @return a next objective
+         */
+        NextObjective addToExisting(ObjectiveContext context);
+
+        /**
+         * Builds the next objective that will be removed, with {@link Operation}
+         * REMOVE_FROM_EXISTING. The context will be used to notify the calling application.
+         *
+         * @param context an objective context
+         * @return a next objective
+         */
+        NextObjective removeFromExisting(ObjectiveContext context);
+
     }
 
 }
diff --git a/core/api/src/main/java/org/onosproject/net/flowobjective/Objective.java b/core/api/src/main/java/org/onosproject/net/flowobjective/Objective.java
index 6ac7a7a..b1d73a7 100644
--- a/core/api/src/main/java/org/onosproject/net/flowobjective/Objective.java
+++ b/core/api/src/main/java/org/onosproject/net/flowobjective/Objective.java
@@ -21,7 +21,7 @@
 import java.util.Optional;
 
 /**
- * Base representation of an flow description.
+ * Base representation of a flow-objective description.
  */
 @Beta
 public interface Objective {
@@ -35,14 +35,30 @@
      */
     enum Operation {
         /**
-         * Adds the objective.
+         * Adds the objective. Can be used for any flow objective. For forwarding
+         * and filtering objectives, existing objectives with identical selector
+         * and priority fields (but different treatments or next) will be replaced.
+         * For next objectives, if modification is desired, ADD will not
+         * do anything - use ADD_TO_EXISTING.
          */
         ADD,
 
         /**
-         * Removes the objective.
+         * Removes the objective. Can be used for any flow objective.
          */
-        REMOVE
+        REMOVE,
+
+        /**
+         * Add to an existing Next Objective. Should not be used for any other
+         * objective.
+         */
+        ADD_TO_EXISTING,
+
+        /**
+         * Remove from an existing Next Objective. Should not be used for any
+         * other objective.
+         */
+        REMOVE_FROM_EXISTING
     }
 
     /**
@@ -129,6 +145,7 @@
          * @return an objective builder
          */
         Builder withPriority(int priority);
+
     }
 
 }
diff --git a/core/api/src/main/java/org/onosproject/net/group/DefaultGroupKey.java b/core/api/src/main/java/org/onosproject/net/group/DefaultGroupKey.java
index 7f00ae7..e1eacd1 100644
--- a/core/api/src/main/java/org/onosproject/net/group/DefaultGroupKey.java
+++ b/core/api/src/main/java/org/onosproject/net/group/DefaultGroupKey.java
@@ -25,6 +25,7 @@
 public class DefaultGroupKey implements GroupKey {
 
     private final byte[] key;
+    protected static final char[] HEX_ARRAY = "0123456789ABCDEF".toCharArray();
 
     public DefaultGroupKey(byte[] key) {
         this.key = checkNotNull(key);
@@ -52,4 +53,20 @@
         return Arrays.hashCode(this.key);
     }
 
+    /**
+     * Returns a hex string representation of the byte array that is used
+     * as a group key. This solution was adapted from
+     * http://stackoverflow.com/questions/9655181/
+     */
+    @Override
+    public String toString() {
+        char[] hexChars = new char[key.length * 2];
+        for (int j = 0; j < key.length; j++) {
+            int v = key[j] & 0xFF;
+            hexChars[j * 2] = HEX_ARRAY[v >>> 4];
+            hexChars[j * 2 + 1] = HEX_ARRAY[v & 0x0F];
+        }
+        return "GroupKey:0x" + new String(hexChars);
+    }
+
 }
\ No newline at end of file
diff --git a/core/net/src/main/java/org/onosproject/net/flowobjective/impl/FlowObjectiveManager.java b/core/net/src/main/java/org/onosproject/net/flowobjective/impl/FlowObjectiveManager.java
index a76a298..5ecdc7a 100644
--- a/core/net/src/main/java/org/onosproject/net/flowobjective/impl/FlowObjectiveManager.java
+++ b/core/net/src/main/java/org/onosproject/net/flowobjective/impl/FlowObjectiveManager.java
@@ -54,6 +54,7 @@
 import org.slf4j.LoggerFactory;
 
 import java.util.Map;
+import java.util.Objects;
 import java.util.Set;
 import java.util.concurrent.ExecutorService;
 
@@ -226,10 +227,11 @@
         if (fwd.nextId() != null &&
                 flowObjectiveStore.getNextGroup(fwd.nextId()) == null) {
             log.trace("Queuing forwarding objective for nextId {}", fwd.nextId());
-            if (pendingForwards.putIfAbsent(fwd.nextId(),
-                                            Sets.newHashSet(new PendingNext(deviceId, fwd))) != null) {
-                Set<PendingNext> pending = pendingForwards.get(fwd.nextId());
-                pending.add(new PendingNext(deviceId, fwd));
+            // TODO: change to computeIfAbsent
+            Set<PendingNext> pnext = pendingForwards.putIfAbsent(fwd.nextId(),
+                                         Sets.newHashSet(new PendingNext(deviceId, fwd)));
+            if (pnext != null) {
+                pnext.add(new PendingNext(deviceId, fwd));
             }
             return true;
         }
@@ -412,5 +414,26 @@
         public ForwardingObjective forwardingObjective() {
             return fwd;
         }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(deviceId, fwd);
+        }
+
+        @Override
+        public boolean equals(final Object obj) {
+            if (this == obj) {
+                return true;
+            }
+            if (!(obj instanceof PendingNext)) {
+                return false;
+            }
+            final PendingNext other = (PendingNext) obj;
+            if (this.deviceId.equals(other.deviceId) &&
+                    this.fwd.equals(other.fwd)) {
+                return true;
+            }
+            return false;
+        }
     }
 }
diff --git a/core/store/dist/src/main/java/org/onosproject/store/group/impl/DistributedGroupStore.java b/core/store/dist/src/main/java/org/onosproject/store/group/impl/DistributedGroupStore.java
index a999ee7..83319c3 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/group/impl/DistributedGroupStore.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/group/impl/DistributedGroupStore.java
@@ -348,9 +348,11 @@
     public void storeGroupDescription(GroupDescription groupDesc) {
         log.debug("In storeGroupDescription");
         // Check if a group is existing with the same key
-        if (getGroup(groupDesc.deviceId(), groupDesc.appCookie()) != null) {
-            log.warn("Group already exists with the same key {}",
-                     groupDesc.appCookie());
+        Group existingGroup = getGroup(groupDesc.deviceId(), groupDesc.appCookie());
+        if (existingGroup != null) {
+            log.warn("Group already exists with the same key {} in dev:{} with id:{}",
+                     groupDesc.appCookie(), groupDesc.deviceId(),
+                     Integer.toHexString(existingGroup.id().id()));
             return;
         }
 
diff --git a/core/store/serializers/src/main/java/org/onosproject/store/serializers/KryoNamespaces.java b/core/store/serializers/src/main/java/org/onosproject/store/serializers/KryoNamespaces.java
index f80a97a..1b883a3 100644
--- a/core/store/serializers/src/main/java/org/onosproject/store/serializers/KryoNamespaces.java
+++ b/core/store/serializers/src/main/java/org/onosproject/store/serializers/KryoNamespaces.java
@@ -368,6 +368,7 @@
                     L2ModificationInstruction.ModVlanPcpInstruction.class,
                     L2ModificationInstruction.PopVlanInstruction.class,
                     L2ModificationInstruction.ModMplsLabelInstruction.class,
+                    L2ModificationInstruction.ModMplsBosInstruction.class,
                     L2ModificationInstruction.ModMplsTtlInstruction.class,
                     L2ModificationInstruction.ModTunnelIdInstruction.class,
                     L3ModificationInstruction.class,