Cleaned-up some javadocs and added some tests.
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/device/impl/package-info.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/device/impl/package-info.java
index a50e32d..bb18f3a 100644
--- a/core/trivial/src/main/java/org/onlab/onos/net/trivial/device/impl/package-info.java
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/device/impl/package-info.java
@@ -1,4 +1,4 @@
 /**
- * Core subsystem for tracking infrastructure devices.
+ * Core subsystem for tracking global inventory of infrastructure devices.
  */
 package org.onlab.onos.net.trivial.device.impl;
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/flow/impl/package-info.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/flow/impl/package-info.java
new file mode 100644
index 0000000..061c2a8
--- /dev/null
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/flow/impl/package-info.java
@@ -0,0 +1,4 @@
+/**
+ * Core subsystem for tracking and manipulating global flow state.
+ */
+package org.onlab.onos.net.trivial.flow.impl;
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/host/impl/package-info.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/host/impl/package-info.java
index 87a4a85..4dcb9ea 100644
--- a/core/trivial/src/main/java/org/onlab/onos/net/trivial/host/impl/package-info.java
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/host/impl/package-info.java
@@ -1,4 +1,4 @@
 /**
- * Core subsystem for tracking edn-station hosts.
+ * Core subsystem for tracking global inventory of end-station hosts.
  */
 package org.onlab.onos.net.trivial.host.impl;
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/link/impl/package-info.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/link/impl/package-info.java
index 09279a7..a3a2031 100644
--- a/core/trivial/src/main/java/org/onlab/onos/net/trivial/link/impl/package-info.java
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/link/impl/package-info.java
@@ -1,4 +1,4 @@
 /**
- * Core subsystem for tracking infrastructure links.
+ * Core subsystem for tracking global inventory of infrastructure links.
  */
 package org.onlab.onos.net.trivial.link.impl;
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/packet/impl/package-info.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/packet/impl/package-info.java
index 5471948..72563a2 100644
--- a/core/trivial/src/main/java/org/onlab/onos/net/trivial/packet/impl/package-info.java
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/packet/impl/package-info.java
@@ -1,4 +1,6 @@
 /**
  * Core subsystem for processing inbound packets and emitting outbound packets.
+ * Processing of inbound packets is always in the local context only, but
+ * emitting outbound packets allows for cluster-wide operation.
  */
 package org.onlab.onos.net.trivial.packet.impl;
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/DefaultTopology.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/DefaultTopology.java
index ef87867..7213497 100644
--- a/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/DefaultTopology.java
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/DefaultTopology.java
@@ -142,6 +142,15 @@
         return clusters.get(clusterId);
     }
 
+    /**
+     * Returns the topology cluster that contains the given device.
+     *
+     * @param deviceId device identifier
+     * @return topology cluster
+     */
+    TopologyCluster getCluster(DeviceId deviceId) {
+        return clustersByDevice.get(deviceId);
+    }
 
     /**
      * Returns the set of cluster devices.
@@ -174,13 +183,13 @@
     }
 
     /**
-     * Indicates whether the given point is part of a broadcast tree.
+     * Indicates whether the given point is part of a broadcast set.
      *
      * @param connectPoint connection point
-     * @return true if in broadcast tree
+     * @return true if in broadcast set
      */
-    boolean isInBroadcastTree(ConnectPoint connectPoint) {
-        // Any non-infrastructure, i.e. edge points are assumed to be OK
+    boolean isBroadcastPoint(ConnectPoint connectPoint) {
+        // Any non-infrastructure, i.e. edge points are assumed to be OK.
         if (!isInfrastructure(connectPoint)) {
             return true;
         }
@@ -191,13 +200,23 @@
             throw new IllegalArgumentException("No cluster found for device " + connectPoint.deviceId());
         }
 
-        // If the broadcast tree is null or empty, or if the point explicitly
-        // belongs to the broadcast tree points, return true;
+        // If the broadcast set is null or empty, or if the point explicitly
+        // belongs to it, return true;
         Set<ConnectPoint> points = broadcastSets.get(cluster.id());
         return points == null || points.isEmpty() || points.contains(connectPoint);
     }
 
     /**
+     * Returns the size of the cluster broadcast set.
+     *
+     * @param clusterId cluster identifier
+     * @return size of the cluster broadcast set
+     */
+    int broadcastSetSize(ClusterId clusterId) {
+        return broadcastSets.get(clusterId).size();
+    }
+
+    /**
      * Returns the set of pre-computed shortest paths between source and
      * destination devices.
      *
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/SimpleTopologyStore.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/SimpleTopologyStore.java
index b51ea53..59360c2 100644
--- a/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/SimpleTopologyStore.java
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/SimpleTopologyStore.java
@@ -144,7 +144,7 @@
      * @return true if broadcast allowed; false otherwise
      */
     boolean isBroadcastPoint(DefaultTopology topology, ConnectPoint connectPoint) {
-        return topology.isInBroadcastTree(connectPoint);
+        return topology.isBroadcastPoint(connectPoint);
     }
 
     /**
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/package-info.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/package-info.java
index 770f38d..d6d162e 100644
--- a/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/package-info.java
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/topology/impl/package-info.java
@@ -1,4 +1,4 @@
 /**
- * Core subsystem for tracking consistent topology graph views.
+ * Core subsystem for tracking global &amp; consistent topology graph views.
  */
 package org.onlab.onos.net.trivial.topology.impl;