diff --git a/core/api/src/main/java/org/onlab/onos/net/AbstractModel.java b/core/api/src/main/java/org/onlab/onos/net/AbstractModel.java
index 482ec68..f5f7689 100644
--- a/core/api/src/main/java/org/onlab/onos/net/AbstractModel.java
+++ b/core/api/src/main/java/org/onlab/onos/net/AbstractModel.java
@@ -5,7 +5,7 @@
 /**
  * Base implementation of a network model entity.
  */
-public class AbstractModel extends AbstractAnnotated implements Provided {
+public abstract class AbstractModel extends AbstractAnnotated implements Provided {
 
     private final ProviderId providerId;