Enhanced DeviceDescription and added default implementation for it.

 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.
  */

 package org.onlab.onos.net;
 
-import org.onlab.onos.net.provider.Provided;
-
 /**
  * Abstraction of a network infrastructure link.
  */

-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.

@@ -3,7 +3,7 @@ package org.onlab.onos.net;
 /**
  * Represents a network topology computation snapshot.
  */
-public interface Topology {
+public interface Topology extends Provided {
 
     /**
      * Returns the time, specified in milliseconds since start of epoch,

+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();
+    }
+
+}

+package org.onlab.onos.net.device;
+
+/**
+ * Default implementation of immutable port description.
+ */
+public class DefaultPortDescription implements PortDescription {
+}

 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 @@ public interface DeviceDescription extends Description {
      */
     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();
+
 }

 package org.onlab.onos.provider.of.device.impl;
 
-import static org.slf4j.LoggerFactory.getLogger;
-
-import java.net.URI;
-import java.net.URISyntaxException;
-
 import org.apache.felix.scr.annotations.Activate;
 import org.apache.felix.scr.annotations.Component;
 import org.apache.felix.scr.annotations.Deactivate;
@@ -13,6 +8,7 @@ import org.apache.felix.scr.annotations.ReferenceCardinality;
 import org.onlab.onos.net.Device;
 import org.onlab.onos.net.DeviceId;
 import org.onlab.onos.net.MastershipRole;
+import org.onlab.onos.net.device.DefaultDeviceDescription;
 import org.onlab.onos.net.device.DeviceDescription;
 import org.onlab.onos.net.device.DeviceProvider;
 import org.onlab.onos.net.device.DeviceProviderRegistry;
@@ -25,6 +21,11 @@ import org.onlab.onos.of.controller.OpenFlowSwitchListener;
 import org.onlab.onos.of.controller.RoleState;
 import org.slf4j.Logger;
 
+import java.net.URI;
+import java.net.URISyntaxException;
+
+import static org.slf4j.LoggerFactory.getLogger;
+
 /**
  * Provider which uses an OpenFlow controller to detect network
  * infrastructure devices.
@@ -90,17 +91,14 @@ public class OpenFlowDeviceProvider extends AbstractProvider implements DevicePr
     }
 
     private class InternalDeviceProvider implements OpenFlowSwitchListener {
-
         @Override
-        public void switchAdded(final Dpid dpid) {
+        public void switchAdded(Dpid dpid) {
             URI uri = buildURI(dpid);
-            providerService.deviceConnected(new DeviceId(uri), new DeviceDescription() {
-
-                @Override
-                public URI deviceURI() {
-                    return buildURI(dpid);
-                }
-            });
+            // TODO: fetch and provide switch desc information
+            DeviceDescription description =
+                    new DefaultDeviceDescription(buildURI(dpid), Device.Type.SWITCH,
+                                                 null, null, null, null);
+            providerService.deviceConnected(new DeviceId(uri), description);
         }
 
         @Override