diff --git a/net/api/src/main/java/org/onlab/onos/net/Element.java b/net/api/src/main/java/org/onlab/onos/net/Element.java
index c11d103..5d3969e 100644
--- a/net/api/src/main/java/org/onlab/onos/net/Element.java
+++ b/net/api/src/main/java/org/onlab/onos/net/Element.java
@@ -1,7 +1,5 @@
 package org.onlab.onos.net;
 
-import org.onlab.onos.net.provider.Provided;
-
 /**
  * Base abstraction of a network element, i.e. an infrastructure device or an end-station host.
  */
diff --git a/net/api/src/main/java/org/onlab/onos/net/Link.java b/net/api/src/main/java/org/onlab/onos/net/Link.java
index 75e026d..38b6f69 100644
--- a/net/api/src/main/java/org/onlab/onos/net/Link.java
+++ b/net/api/src/main/java/org/onlab/onos/net/Link.java
@@ -1,7 +1,5 @@
 package org.onlab.onos.net;
 
-import org.onlab.onos.net.provider.Provided;
-
 /**
  * Abstraction of a network infrastructure link.
  */
diff --git a/net/api/src/main/java/org/onlab/onos/net/provider/Provided.java b/net/api/src/main/java/org/onlab/onos/net/Provided.java
similarity index 77%
rename from net/api/src/main/java/org/onlab/onos/net/provider/Provided.java
rename to net/api/src/main/java/org/onlab/onos/net/Provided.java
index 89364c2..92bfe95 100644
--- a/net/api/src/main/java/org/onlab/onos/net/provider/Provided.java
+++ b/net/api/src/main/java/org/onlab/onos/net/Provided.java
@@ -1,4 +1,6 @@
-package org.onlab.onos.net.provider;
+package org.onlab.onos.net;
+
+import org.onlab.onos.net.provider.ProviderId;
 
 /**
  * Abstraction of an entity supplied by a provider.
diff --git a/net/api/src/main/java/org/onlab/onos/net/Topology.java b/net/api/src/main/java/org/onlab/onos/net/Topology.java
index c8a01e9..ed1bfb5 100644
--- a/net/api/src/main/java/org/onlab/onos/net/Topology.java
+++ b/net/api/src/main/java/org/onlab/onos/net/Topology.java
@@ -3,7 +3,7 @@
 /**
  * Represents a network topology computation snapshot.
  */
-public interface Topology {
+public interface Topology extends Provided {
 
     /**
      * Returns the time, specified in milliseconds since start of epoch,
diff --git a/net/api/src/main/java/org/onlab/onos/net/device/DefaultDeviceDescription.java b/net/api/src/main/java/org/onlab/onos/net/device/DefaultDeviceDescription.java
new file mode 100644
index 0000000..3d340b2
--- /dev/null
+++ b/net/api/src/main/java/org/onlab/onos/net/device/DefaultDeviceDescription.java
@@ -0,0 +1,80 @@
+package org.onlab.onos.net.device;
+
+import java.net.URI;
+
+import static com.google.common.base.Objects.toStringHelper;
+import static com.google.common.base.Preconditions.checkNotNull;
+import static org.onlab.onos.net.Device.Type;
+
+/**
+ * Default implementation of immutable device description entity.
+ */
+public class DefaultDeviceDescription implements DeviceDescription {
+    private final URI uri;
+    private final Type type;
+    private final String manufacturer;
+    private final String hwVersion;
+    private final String swVersion;
+    private final String serialNumber;
+
+    /**
+     * Creates a device description using the supplied information.
+     *
+     * @param uri          device URI
+     * @param type         device type
+     * @param manufacturer device manufacturer
+     * @param hwVersion    device HW version
+     * @param swVersion    device SW version
+     * @param serialNumber device serial number
+     */
+    public DefaultDeviceDescription(URI uri, Type type, String manufacturer,
+                                    String hwVersion, String swVersion,
+                                    String serialNumber) {
+        this.uri = checkNotNull(uri, "Device URI cannot be null");
+        this.type = checkNotNull(type, "Device type cannot be null");
+        this.manufacturer = manufacturer;
+        this.hwVersion = hwVersion;
+        this.swVersion = swVersion;
+        this.serialNumber = serialNumber;
+    }
+
+    @Override
+    public URI deviceURI() {
+        return uri;
+    }
+
+    @Override
+    public Type type() {
+        return type;
+    }
+
+    @Override
+    public String manufacturer() {
+        return manufacturer;
+    }
+
+    @Override
+    public String hwVersion() {
+        return hwVersion;
+    }
+
+    @Override
+    public String swVersion() {
+        return swVersion;
+    }
+
+    @Override
+    public String serialNumber() {
+        return serialNumber;
+    }
+
+    @Override
+    public String toString() {
+        return toStringHelper(this)
+                .add("uri", uri).add("type", type).add("mfr", manufacturer)
+                .add("hw", hwVersion).add("sw", swVersion)
+                .add("serial", serialNumber)
+                .toString();
+    }
+
+}
diff --git a/net/api/src/main/java/org/onlab/onos/net/device/DefaultPortDescription.java b/net/api/src/main/java/org/onlab/onos/net/device/DefaultPortDescription.java
new file mode 100644
index 0000000..c171098
--- /dev/null
+++ b/net/api/src/main/java/org/onlab/onos/net/device/DefaultPortDescription.java
@@ -0,0 +1,7 @@
+package org.onlab.onos.net.device;
+
+/**
+ * Default implementation of immutable port description.
+ */
+public class DefaultPortDescription implements PortDescription {
+}
diff --git a/net/api/src/main/java/org/onlab/onos/net/device/DeviceDescription.java b/net/api/src/main/java/org/onlab/onos/net/device/DeviceDescription.java
index 2b83890..e32c19d 100644
--- a/net/api/src/main/java/org/onlab/onos/net/device/DeviceDescription.java
+++ b/net/api/src/main/java/org/onlab/onos/net/device/DeviceDescription.java
@@ -1,6 +1,7 @@
 package org.onlab.onos.net.device;
 
 import org.onlab.onos.net.Description;
+import org.onlab.onos.net.Device;
 
 import java.net.URI;
 
@@ -18,4 +19,39 @@
      */
     URI deviceURI();
 
+    /**
+     * Returns the type of the infrastructure device.
+     *
+     * @return type of the device
+     */
+    Device.Type type();
+
+    /**
+     * Returns the device manufacturer name.
+     *
+     * @return manufacturer name
+     */
+    String manufacturer();
+
+    /**
+     * Returns the device hardware version.
+     *
+     * @return hardware version
+     */
+    String hwVersion();
+
+    /**
+     * Returns the device software version.
+     *
+     * @return software version
+     */
+    String swVersion();
+
+    /**
+     * Returns the device serial number.
+     *
+     * @return serial number
+     */
+    String serialNumber();
+
 }