Enhanced the CLIs.
diff --git a/net/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleDeviceStore.java b/net/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleDeviceStore.java
index 3c05aba..fdffad2 100644
--- a/net/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleDeviceStore.java
+++ b/net/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleDeviceStore.java
@@ -271,6 +271,16 @@
     }
 
     /**
+     * Indicates whether the specified device is available/online.
+     *
+     * @param deviceId device identifier
+     * @return true if device is available
+     */
+    boolean isAvailable(DeviceId deviceId) {
+        return availableDevices.contains(deviceId);
+    }
+
+    /**
      * Returns the mastership role determined for this device.
      *
      * @param deviceId device identifier