diff --git a/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/DefaultVirtualDevice.java b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/DefaultVirtualDevice.java
index e3339a9..06225ff 100644
--- a/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/DefaultVirtualDevice.java
+++ b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/DefaultVirtualDevice.java
@@ -27,7 +27,7 @@
 /**
  * Default representation of a virtual device.
  */
-public class DefaultVirtualDevice extends DefaultDevice implements VirtualDevice {
+public final class DefaultVirtualDevice extends DefaultDevice implements VirtualDevice {
 
     private static final String VIRTUAL = "virtual";
     private static final ProviderId PID = new ProviderId(VIRTUAL, VIRTUAL);
@@ -53,7 +53,7 @@
 
     @Override
     public int hashCode() {
-        return 31 * super.hashCode() + networkId.hashCode();
+        return Objects.hash(networkId);
     }
 
     @Override
diff --git a/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/DefaultVirtualLink.java b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/DefaultVirtualLink.java
new file mode 100644
index 0000000..89374d4
--- /dev/null
+++ b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/DefaultVirtualLink.java
@@ -0,0 +1,91 @@
+/*
+ * Copyright 2016 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.incubator.net.virtual;
+
+import org.onosproject.incubator.net.tunnel.TunnelId;
+import org.onosproject.net.ConnectPoint;
+import org.onosproject.net.DefaultAnnotations;
+import org.onosproject.net.DefaultLink;
+import org.onosproject.net.provider.ProviderId;
+
+import java.util.Objects;
+
+import static com.google.common.base.MoreObjects.toStringHelper;
+
+/**
+ * Default representation of a virtual link.
+ */
+public final class DefaultVirtualLink extends DefaultLink implements VirtualLink {
+
+    private static final String VIRTUAL = "virtual";
+    private static final ProviderId PID = new ProviderId(VIRTUAL, VIRTUAL);
+
+    private final NetworkId networkId;
+    private final TunnelId tunnelId;
+
+    /**
+     * Constructor for a default virtual link.
+     *
+     * @param networkId network identifier
+     * @param src       source connection point
+     * @param dst       destination connection point
+     * @param tunnelId  tunnel identifier
+     */
+    public DefaultVirtualLink(NetworkId networkId, ConnectPoint src, ConnectPoint dst, TunnelId tunnelId) {
+        super(PID, src, dst, Type.VIRTUAL, DefaultAnnotations.builder().build());
+        this.networkId = networkId;
+        this.tunnelId = tunnelId;
+    }
+
+    @Override
+    public NetworkId networkId() {
+        return networkId;
+    }
+
+    /**
+     * Returns the tunnel identifier.
+     *
+     * @return tunnel identifier.
+     */
+    public TunnelId tunnelId() {
+        return tunnelId;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(networkId, tunnelId);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj instanceof DefaultVirtualLink) {
+            DefaultVirtualLink that = (DefaultVirtualLink) obj;
+            return super.equals(that) &&
+                    Objects.equals(this.networkId, that.networkId) &&
+                    Objects.equals(this.tunnelId, that.tunnelId);
+        }
+        return false;
+    }
+
+    @Override
+    public String toString() {
+        return toStringHelper(this).add("networkId", networkId).add("tunnelId", tunnelId).toString();
+    }
+}
diff --git a/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/DefaultVirtualNetwork.java b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/DefaultVirtualNetwork.java
index c114191..360d385 100644
--- a/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/DefaultVirtualNetwork.java
+++ b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/DefaultVirtualNetwork.java
@@ -22,7 +22,7 @@
 /**
  * Default implementation of the virtual network descriptor.
  */
-public class DefaultVirtualNetwork implements VirtualNetwork {
+public final class DefaultVirtualNetwork implements VirtualNetwork {
 
     private final NetworkId id;
     private final TenantId tenantId;
diff --git a/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/DefaultVirtualPort.java b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/DefaultVirtualPort.java
new file mode 100644
index 0000000..ad56efb
--- /dev/null
+++ b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/DefaultVirtualPort.java
@@ -0,0 +1,78 @@
+/*
+ * Copyright 2016 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.incubator.net.virtual;
+
+import org.onosproject.net.DefaultAnnotations;
+import org.onosproject.net.DefaultPort;
+import org.onosproject.net.Device;
+import org.onosproject.net.Element;
+import org.onosproject.net.Port;
+import org.onosproject.net.PortNumber;
+
+import java.util.Objects;
+
+import static com.google.common.base.MoreObjects.toStringHelper;
+
+/**
+ * Default representation of a virtual port.
+ */
+public final class DefaultVirtualPort extends DefaultPort implements VirtualPort {
+
+
+    private final NetworkId networkId;
+    private final Port realizedBy;
+
+    public DefaultVirtualPort(NetworkId networkId, Device device, PortNumber portNumber, Port realizedBy) {
+        super((Element) device, portNumber, false, DefaultAnnotations.builder().build());
+        this.networkId = networkId;
+        this.realizedBy = realizedBy;
+    }
+
+    public NetworkId networkId() {
+        return networkId;
+    }
+
+    @Override
+    public Port realizedBy() {
+        return realizedBy;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(networkId, realizedBy);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj instanceof DefaultVirtualPort) {
+            DefaultVirtualPort that = (DefaultVirtualPort) obj;
+            return super.equals(that) &&
+                    Objects.equals(this.networkId, that.networkId) &&
+                    Objects.equals(this.realizedBy, that.realizedBy);
+        }
+        return false;
+    }
+
+    @Override
+    public String toString() {
+        return toStringHelper(this).add("networkId", networkId).add("realizedBy", realizedBy).toString();
+    }
+
+}
diff --git a/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/VirtualNetworkService.java b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/VirtualNetworkService.java
index 01681ef..c83b2c5 100644
--- a/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/VirtualNetworkService.java
+++ b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/VirtualNetworkService.java
@@ -27,6 +27,11 @@
 public interface VirtualNetworkService {
 
     /**
+     * The topic used for obtaining globally unique ids.
+     */
+    String VIRTUAL_NETWORK_TOPIC = "virtual-network-ids";
+
+    /**
      * Returns a collection of all virtual networks created on behalf of the
      * specified tenant.
      *