Added default link description & model entities.
diff --git a/net/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleLinkManager.java b/net/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleLinkManager.java
index 8efa526..b5d8cc4 100644
--- a/net/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleLinkManager.java
+++ b/net/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleLinkManager.java
@@ -34,6 +34,8 @@
     private final AbstractListenerRegistry<LinkEvent, LinkListener>
             listenerRegistry = new AbstractListenerRegistry<>();
 
+    private final SimpleLinkStore store = new SimpleLinkStore();
+
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     private EventDeliveryService eventDispatcher;