diff --git a/utils/misc/src/main/java/org/onlab/packet/Ethernet.java b/utils/misc/src/main/java/org/onlab/packet/Ethernet.java
index 69e6480..a0e07e9 100644
--- a/utils/misc/src/main/java/org/onlab/packet/Ethernet.java
+++ b/utils/misc/src/main/java/org/onlab/packet/Ethernet.java
@@ -38,6 +38,7 @@
  */
 public class Ethernet extends BasePacket {
     private static final String HEXES = "0123456789ABCDEF";
+    private static final String HEX_PROTO = "0x%s";
 
     public static final short TYPE_ARP = EthType.EtherType.ARP.ethType().toShort();
     public static final short TYPE_RARP = EthType.EtherType.RARP.ethType().toShort();
@@ -494,7 +495,13 @@
         } else if (pkt instanceof DHCP) {
             sb.append("dhcp");
         } else {
-            sb.append(this.getEtherType());
+            /*
+             * When we don't know the protocol, we print using
+             * the well known hex format instead of a decimal
+             * value.
+             */
+            sb.append(String.format(HEX_PROTO,
+                                    Integer.toHexString(this.getEtherType() & 0xffff)));
         }
 
         sb.append("\ndl_vlan: ");
diff --git a/utils/misc/src/main/java/org/onlab/packet/IpAddress.java b/utils/misc/src/main/java/org/onlab/packet/IpAddress.java
index bf01406..d992e52 100644
--- a/utils/misc/src/main/java/org/onlab/packet/IpAddress.java
+++ b/utils/misc/src/main/java/org/onlab/packet/IpAddress.java
@@ -15,15 +15,16 @@
  */
 package org.onlab.packet;
 
-import java.net.InetAddress;
-import java.net.UnknownHostException;
+import com.google.common.net.InetAddresses;
+import com.google.common.primitives.UnsignedBytes;
+
 import java.net.Inet4Address;
 import java.net.Inet6Address;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
 import java.nio.ByteBuffer;
 import java.util.Arrays;
 import java.util.Objects;
-import com.google.common.net.InetAddresses;
-import com.google.common.primitives.UnsignedBytes;
 
 
 /**
@@ -71,6 +72,14 @@
     }
 
     /**
+     * Default constructor for Kryo serialization.
+     */
+    protected IpAddress() {
+        this.version = null;
+        this.octets = null;
+    }
+
+    /**
      * Returns the IP version of this address.
      *
      * @return the version
diff --git a/utils/misc/src/main/java/org/onlab/packet/IpPrefix.java b/utils/misc/src/main/java/org/onlab/packet/IpPrefix.java
index a076530..7f50327 100644
--- a/utils/misc/src/main/java/org/onlab/packet/IpPrefix.java
+++ b/utils/misc/src/main/java/org/onlab/packet/IpPrefix.java
@@ -66,6 +66,14 @@
     }
 
     /**
+     * Default constructor for Kryo serialization.
+     */
+    protected IpPrefix() {
+        this.address = null;
+        this.prefixLength = 0;
+    }
+
+    /**
      * Returns the IP version of the prefix.
      *
      * @return the IP version of the prefix