diff --git a/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DefaultTransactionalMap.java b/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DefaultTransactionalMap.java
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--- /dev/null
+++ b/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DefaultTransactionalMap.java
@@ -0,0 +1,243 @@
+/*
+ * Copyright 2015 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.store.consistent.impl;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.stream.Collectors;
+import java.util.Set;
+
+import org.onlab.util.HexString;
+import org.onosproject.store.service.ConsistentMap;
+import org.onosproject.store.service.Serializer;
+import org.onosproject.store.service.TransactionContext;
+import org.onosproject.store.service.TransactionalMap;
+import org.onosproject.store.service.UpdateOperation;
+import org.onosproject.store.service.Versioned;
+
+import static com.google.common.base.Preconditions.*;
+
+import com.google.common.collect.Lists;
+import com.google.common.collect.Maps;
+import com.google.common.collect.Sets;
+
+/**
+ * Default Transactional Map implementation that provides a repeatable reads
+ * transaction isolation level.
+ *
+ * @param <K> key type
+ * @param <V> value type.
+ */
+public class DefaultTransactionalMap<K, V> implements TransactionalMap<K, V> {
+
+    private final TransactionContext txContext;
+    private static final String TX_CLOSED_ERROR = "Transaction is closed";
+    private final ConsistentMap<K, V> backingMap;
+    private final String name;
+    private final Serializer serializer;
+    private final Map<K, Versioned<V>> readCache = Maps.newConcurrentMap();
+    private final Map<K, V> writeCache = Maps.newConcurrentMap();
+    private final Set<K> deleteSet = Sets.newConcurrentHashSet();
+
+    public DefaultTransactionalMap(
+            String name,
+            ConsistentMap<K, V> backingMap,
+            TransactionContext txContext,
+            Serializer serializer) {
+        this.name = name;
+        this.backingMap = backingMap;
+        this.txContext = txContext;
+        this.serializer = serializer;
+    }
+
+    @Override
+    public V get(K key) {
+        checkState(txContext.isOpen(), TX_CLOSED_ERROR);
+        if (deleteSet.contains(key)) {
+            return null;
+        } else if (writeCache.containsKey(key)) {
+            return writeCache.get(key);
+        } else {
+            if (!readCache.containsKey(key)) {
+                readCache.put(key, backingMap.get(key));
+            }
+            Versioned<V> v = readCache.get(key);
+            return v != null ? v.value() : null;
+        }
+    }
+
+    @Override
+    public V put(K key, V value) {
+        checkState(txContext.isOpen(), TX_CLOSED_ERROR);
+        Versioned<V> original = readCache.get(key);
+        V recentUpdate = writeCache.put(key, value);
+        deleteSet.remove(key);
+        return recentUpdate == null ? (original != null ? original.value() : null) : recentUpdate;
+    }
+
+    @Override
+    public V remove(K key) {
+        checkState(txContext.isOpen(), TX_CLOSED_ERROR);
+        Versioned<V> original = readCache.get(key);
+        V recentUpdate = writeCache.remove(key);
+        deleteSet.add(key);
+        return recentUpdate == null ? (original != null ? original.value() : null) : recentUpdate;
+    }
+
+    @Override
+    public boolean remove(K key, V value) {
+        V currentValue = get(key);
+        if (value.equals(currentValue)) {
+            remove(key);
+            return true;
+        }
+        return false;
+    }
+
+    @Override
+    public boolean replace(K key, V oldValue, V newValue) {
+        V currentValue = get(key);
+        if (oldValue.equals(currentValue)) {
+            put(key, newValue);
+            return true;
+        }
+        return false;
+    }
+
+    @Override
+    public int size() {
+        // TODO
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return size() == 0;
+    }
+
+    @Override
+    public boolean containsKey(K key) {
+        return get(key) != null;
+    }
+
+    @Override
+    public boolean containsValue(V value) {
+        // TODO
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void clear() {
+        // TODO
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public Set<K> keySet() {
+        // TODO
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public Collection<V> values() {
+        // TODO
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public Set<Entry<K, V>> entrySet() {
+        // TODO
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public V putIfAbsent(K key, V value) {
+        V currentValue = get(key);
+        if (currentValue == null) {
+            put(key, value);
+            return null;
+        }
+        return currentValue;
+    }
+
+    protected List<UpdateOperation<String, byte[]>> prepareDatabaseUpdates() {
+        List<UpdateOperation<K, V>> updates = Lists.newLinkedList();
+        deleteSet.forEach(key -> {
+            Versioned<V> original = readCache.get(key);
+            if (original != null) {
+                updates.add(UpdateOperation.<K, V>newBuilder()
+                        .withTableName(name)
+                        .withType(UpdateOperation.Type.REMOVE_IF_VERSION_MATCH)
+                        .withKey(key)
+                        .withCurrentVersion(original.version())
+                        .build());
+            }
+        });
+        writeCache.forEach((key, value) -> {
+            Versioned<V> original = readCache.get(key);
+            if (original == null) {
+                updates.add(UpdateOperation.<K, V>newBuilder()
+                        .withTableName(name)
+                        .withType(UpdateOperation.Type.PUT_IF_ABSENT)
+                        .withKey(key)
+                        .withValue(value)
+                        .build());
+            } else {
+                updates.add(UpdateOperation.<K, V>newBuilder()
+                        .withTableName(name)
+                        .withType(UpdateOperation.Type.PUT_IF_VERSION_MATCH)
+                        .withKey(key)
+                        .withCurrentVersion(original.version())
+                        .withValue(value)
+                        .build());
+            }
+        });
+        return updates.stream().map(this::toRawUpdateOperation).collect(Collectors.toList());
+    }
+
+    private UpdateOperation<String, byte[]> toRawUpdateOperation(UpdateOperation<K, V> update) {
+
+        UpdateOperation.Builder<String, byte[]> rawUpdate = UpdateOperation.<String, byte[]>newBuilder();
+
+        rawUpdate = rawUpdate.withKey(HexString.toHexString(serializer.encode(update.key())))
+            .withCurrentVersion(update.currentVersion())
+            .withType(update.type());
+
+        rawUpdate = rawUpdate.withTableName(update.tableName());
+
+        if (update.value() != null) {
+            rawUpdate = rawUpdate.withValue(serializer.encode(update.value()));
+        }
+
+        if (update.currentValue() != null) {
+            rawUpdate = rawUpdate.withCurrentValue(serializer.encode(update.currentValue()));
+        }
+
+        return rawUpdate.build();
+    }
+
+    /**
+     * Discards all changes made to this transactional map.
+     */
+    protected void rollback() {
+        readCache.clear();
+        writeCache.clear();
+        deleteSet.clear();
+    }
+}
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