diff --git a/core/store/src/main/java/org/onlab/onos/store/device/impl/PortNumberSerializer.java b/core/store/src/main/java/org/onlab/onos/store/device/impl/PortNumberSerializer.java
new file mode 100644
index 0000000..4483187
--- /dev/null
+++ b/core/store/src/main/java/org/onlab/onos/store/device/impl/PortNumberSerializer.java
@@ -0,0 +1,29 @@
+package org.onlab.onos.store.device.impl;
+
+import org.onlab.onos.net.PortNumber;
+
+import com.esotericsoftware.kryo.Kryo;
+import com.esotericsoftware.kryo.Serializer;
+import com.esotericsoftware.kryo.io.Input;
+import com.esotericsoftware.kryo.io.Output;
+
+// TODO move to util, etc.
+public final class PortNumberSerializer extends
+        Serializer<PortNumber> {
+
+    public PortNumberSerializer() {
+        // non-null, immutable
+        super(false, true);
+    }
+
+    @Override
+    public void write(Kryo kryo, Output output, PortNumber object) {
+        output.writeLong(object.toLong());
+    }
+
+    @Override
+    public PortNumber read(Kryo kryo, Input input,
+            Class<PortNumber> type) {
+        return PortNumber.portNumber(input.readLong());
+    }
+}