BLE notification never received on android 4.4

Question

I am developing an application in android for communicating with Blugiga BLE 112. Here my BLE device is designed to provide data to android as Indications, I can successfully write characteristic but i am not getting any indications on android. Following is what i tried for setting notification.

public void setCharectresticNotification(
        BluetoothGattCharacteristic characteristic,
        BluetoothGattDescriptor descriptor) {
    mBluetoothGatt.setCharacteristicNotification(characteristic, true);
        descriptor
                .setValue(BluetoothGattDescriptor.ENABLE_INDICATION_VALUE);

        mBluetoothGatt.writeDescriptor(descriptor);


}

I am calling this method once i get the characteristic and descriptor successfully.

Also please provide the flow i should be following to set notification once connection has been established.