diff --git a/core/api/src/main/java/org/onosproject/net/device/DeviceStore.java b/core/api/src/main/java/org/onosproject/net/device/DeviceStore.java
index 626097d..cadfa25 100644
--- a/core/api/src/main/java/org/onosproject/net/device/DeviceStore.java
+++ b/core/api/src/main/java/org/onosproject/net/device/DeviceStore.java
@@ -39,6 +39,13 @@
     int getDeviceCount();
 
     /**
+     * Returns the number of currently available devices known to the system.
+     *
+     * @return number of devices
+     */
+    int getAvailableDeviceCount();
+
+    /**
      * Returns an iterable collection of all devices known to the system.
      *
      * @return device collection
diff --git a/core/api/src/test/java/org/onosproject/net/device/DeviceStoreAdapter.java b/core/api/src/test/java/org/onosproject/net/device/DeviceStoreAdapter.java
index b09b35f..b4861ea 100644
--- a/core/api/src/test/java/org/onosproject/net/device/DeviceStoreAdapter.java
+++ b/core/api/src/test/java/org/onosproject/net/device/DeviceStoreAdapter.java
@@ -36,6 +36,11 @@
     }
 
     @Override
+    public int getAvailableDeviceCount() {
+        return 0;
+    }
+
+    @Override
     public Iterable<Device> getDevices() {
         return null;
     }
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleDeviceStore.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleDeviceStore.java
index 04d376c..a3761b0 100644
--- a/core/common/src/test/java/org/onosproject/store/trivial/SimpleDeviceStore.java
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleDeviceStore.java
@@ -126,6 +126,11 @@
     }
 
     @Override
+    public int getAvailableDeviceCount() {
+        return availableDevices.size();
+    }
+
+    @Override
     public Iterable<Device> getDevices() {
         return Collections.unmodifiableCollection(devices.values());
     }
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleDeviceStoreTest.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleDeviceStoreTest.java
index f8eb1ba..c4ceb18 100644
--- a/core/common/src/test/java/org/onosproject/store/trivial/SimpleDeviceStoreTest.java
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleDeviceStoreTest.java
@@ -156,6 +156,22 @@
     }
 
     @Test
+    public final void testGetAvailableDeviceCount() {
+        assertEquals("initialy empty", 0, deviceStore.getAvailableDeviceCount());
+
+        putDevice(DID1, SW1);
+        putDevice(DID2, SW2);
+
+        deviceStore.markOffline(DID1);
+
+        assertEquals("expect 1 available device", 1, deviceStore.getAvailableDeviceCount());
+
+        putDevice(DID1, SW1);
+
+        assertEquals("expect 2 available devices", 2, deviceStore.getAvailableDeviceCount());
+    }
+
+    @Test
     public final void testGetDevices() {
         assertEquals("initialy empty", 0, Iterables.size(deviceStore.getDevices()));
 
diff --git a/core/store/dist/src/main/java/org/onosproject/store/device/impl/ECDeviceStore.java b/core/store/dist/src/main/java/org/onosproject/store/device/impl/ECDeviceStore.java
index 062fd46..e73eaea 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/device/impl/ECDeviceStore.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/device/impl/ECDeviceStore.java
@@ -247,6 +247,11 @@
     }
 
     @Override
+    public int getAvailableDeviceCount() {
+        return availableDevices.size();
+    }
+
+    @Override
     public Device getDevice(DeviceId deviceId) {
         return devices.get(deviceId);
     }
diff --git a/core/store/dist/src/main/java/org/onosproject/store/device/impl/GossipDeviceStore.java b/core/store/dist/src/main/java/org/onosproject/store/device/impl/GossipDeviceStore.java
index 00dacc2..7f1539d 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/device/impl/GossipDeviceStore.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/device/impl/GossipDeviceStore.java
@@ -276,6 +276,11 @@
     }
 
     @Override
+    public int getAvailableDeviceCount() {
+        return availableDevices.size();
+    }
+
+    @Override
     public Iterable<Device> getDevices() {
         return Collections.unmodifiableCollection(devices.values());
     }
diff --git a/core/store/dist/src/test/java/org/onosproject/store/device/impl/GossipDeviceStoreTest.java b/core/store/dist/src/test/java/org/onosproject/store/device/impl/GossipDeviceStoreTest.java
index 4df97a1..4f9f20cd 100644
--- a/core/store/dist/src/test/java/org/onosproject/store/device/impl/GossipDeviceStoreTest.java
+++ b/core/store/dist/src/test/java/org/onosproject/store/device/impl/GossipDeviceStoreTest.java
@@ -299,6 +299,22 @@
     }
 
     @Test
+    public final void testGetAvailableDeviceCount() {
+        assertEquals("initialy empty", 0, deviceStore.getAvailableDeviceCount());
+
+        putDevice(DID1, SW1);
+        putDevice(DID2, SW2);
+
+        deviceStore.markOffline(DID1);
+
+        assertEquals("expect 1 available device", 1, deviceStore.getAvailableDeviceCount());
+
+        deviceStore.markOnline(DID1);
+
+        assertEquals("expect 2 available devices", 2, deviceStore.getAvailableDeviceCount());
+    }
+
+    @Test
     public final void testGetDevices() {
         assertEquals("initialy empty", 0, Iterables.size(deviceStore.getDevices()));