Added constructors for serialization of the new constraint types and registered the types with the serializer pool.
diff --git a/core/api/src/main/java/org/onlab/onos/net/resource/Bandwidth.java b/core/api/src/main/java/org/onlab/onos/net/resource/Bandwidth.java
index 9dddb86..fcb3cd8 100644
--- a/core/api/src/main/java/org/onlab/onos/net/resource/Bandwidth.java
+++ b/core/api/src/main/java/org/onlab/onos/net/resource/Bandwidth.java
@@ -33,6 +33,11 @@
         this.bandwidth = bandwidth;
     }
 
+    // Constructor for serialization
+    private Bandwidth() {
+        this.bandwidth = 0;
+    }
+
     /**
      * Creates a new instance with given bandwidth.
      *