diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/ArpOpcode.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/ArpOpcode.java
index 5e710ca..5ab940d 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/ArpOpcode.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/ArpOpcode.java
@@ -60,7 +60,10 @@
 
     private static final int MIN_OPCODE = 0;
     private static final int MAX_OPCODE = 0xFFFF;
-    
+
+    private static final int NONE_VAL = 0;
+    public static final ArpOpcode NONE = new ArpOpcode(NONE_VAL);
+
     public static final ArpOpcode NO_MASK = new ArpOpcode(0xFFFFFFFF);
     public static final ArpOpcode FULL_MASK = new ArpOpcode(0x00000000);
 
@@ -83,6 +86,8 @@
         if (opcode < MIN_OPCODE || opcode > MAX_OPCODE)
             throw new IllegalArgumentException("Invalid ARP opcode: " + opcode);
         switch (opcode) {
+            case NONE_VAL:
+                return NONE;
             case ARP_OPCODE_VAL_REQUEST:
                 return ARP_OPCODE_REQUEST;
             case ARP_OPCODE_VAL_REPLY:
@@ -137,11 +142,11 @@
                 return new ArpOpcode(opcode);
         }
     }
-    
+
     public void write2Bytes(ChannelBuffer c) {
         c.writeShort(this.opcode);
     }
-    
+
     public static ArpOpcode read2Bytes(ChannelBuffer c) {
         return ArpOpcode.of(c.readUnsignedShort());
     }
@@ -150,9 +155,9 @@
     public ArpOpcode applyMask(ArpOpcode mask) {
         return ArpOpcode.of(this.opcode & mask.opcode);
     }
-    
+
     public int getOpCode() {
         return opcode;
     }
-    
+
 }
\ No newline at end of file
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/EthType.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/EthType.java
index 4c18e21..abd4bff 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/EthType.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/EthType.java
@@ -5,7 +5,7 @@
 
 /**
  * EtherType field representation.
- * 
+ *
  * @author Yotam Harchol (yotam.harchol@bigswitch.com)
  */
 public class EthType implements OFValueType<EthType> {
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/ICMPv4Code.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/ICMPv4Code.java
index 46ada58..a6544c9 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/ICMPv4Code.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/ICMPv4Code.java
@@ -3,7 +3,7 @@
 import org.jboss.netty.buffer.ChannelBuffer;
 
 /**
- * 
+ *
  * @author Yotam Harchol (yotam.harchol@bigswitch.com)
  *
  */
@@ -13,7 +13,10 @@
     final static short MAX_CODE = 0xFF;
 
     private final short code;
-    
+
+    private static final short NONE_VAL = 0;
+    public static final ICMPv4Code NONE = new ICMPv4Code(NONE_VAL);
+
     public static final ICMPv4Code NO_MASK = new ICMPv4Code((short)0xFFFF);
     public static final ICMPv4Code FULL_MASK = new ICMPv4Code((short)0x0000);
 
@@ -22,6 +25,9 @@
     }
 
     public static ICMPv4Code of(short code) {
+        if(code == NONE_VAL)
+            return NONE;
+
         if (code > MAX_CODE || code < 0)
             throw new IllegalArgumentException("Illegal ICMPv4 code: " + code);
         return new ICMPv4Code(code);
@@ -31,15 +37,15 @@
     public int getLength() {
         return LENGTH;
     }
-    
+
     public short getCode() {
         return code;
     }
-    
+
     public void writeByte(ChannelBuffer c) {
         c.writeByte(this.code);
     }
-    
+
     public static ICMPv4Code readByte(ChannelBuffer c) {
         return ICMPv4Code.of(c.readUnsignedByte());
     }
@@ -49,5 +55,5 @@
         return ICMPv4Code.of((short)(this.code & mask.code));
     }
 
-    
+
 }
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/ICMPv4Type.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/ICMPv4Type.java
index 00a789b..5190d4e 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/ICMPv4Type.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/ICMPv4Type.java
@@ -64,13 +64,16 @@
     public static final ICMPv4Type ICMPV4_TYPE_PHOTURIS = new ICMPv4Type(ICMPV4_TYPE_VAL_PHOTURIS);
     public static final ICMPv4Type ICMPV4_TYPE_EXPERIMENTAL_MOBILITY    = new ICMPv4Type(ICMPV4_TYPE_VAL_EXPERIMENTAL_MOBILITY);
 
+    // HACK alert - we're disapproriating ICMPV4_TYPE_ECHO_REPLY (value 0) as 'none' as well
+    public static final ICMPv4Type NONE   = ICMPV4_TYPE_ECHO_REPLY;
+
     public static final ICMPv4Type NO_MASK = new ICMPv4Type((short)0xFFFF);
     public static final ICMPv4Type FULL_MASK = new ICMPv4Type((short)0x0000);
 
     private final short type;
-    
+
     private static final int MIN_TYPE = 0;
-    private static final int MAX_TYPE = 0xFF;    
+    private static final int MAX_TYPE = 0xFF;
 
     private ICMPv4Type(short type) {
         this.type = type;
@@ -145,15 +148,15 @@
     public int getLength() {
         return LENGTH;
     }
-    
+
     public short getType() {
         return type;
     }
-    
+
     public void writeByte(ChannelBuffer c) {
         c.writeByte(this.type);
     }
-    
+
     public static ICMPv4Type readByte(ChannelBuffer c) {
         return ICMPv4Type.of(c.readUnsignedByte());
     }
@@ -163,5 +166,5 @@
         return ICMPv4Type.of((short)(this.type & mask.type));
     }
 
-    
+
 }
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv4Address.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv4Address.java
index ad454eb..5ef301b 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv4Address.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv4Address.java
@@ -13,6 +13,9 @@
     static final int LENGTH = 4;
     private final int rawValue;
 
+    private final static int NONE_VAL = 0x0;
+    public final static IPv4Address NONE = new IPv4Address(NONE_VAL);
+
     public static final IPv4Address NO_MASK = IPv4Address.of(0xFFFFFFFF);
     public static final IPv4Address FULL_MASK = IPv4Address.of(0x00000000);
 
@@ -33,6 +36,8 @@
     }
 
     public static IPv4Address of(final int raw) {
+        if(raw == NONE_VAL)
+            return NONE;
         return new IPv4Address(raw);
     }
 
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv4AddressWithMask.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv4AddressWithMask.java
index a6ec439..45f10d1 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv4AddressWithMask.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv4AddressWithMask.java
@@ -1,6 +1,7 @@
 package org.projectfloodlight.openflow.types;
 
 public class IPv4AddressWithMask extends Masked<IPv4Address> {
+    public final static IPv4AddressWithMask NONE = of(IPv4Address.NONE, IPv4Address.NONE);
 
     private IPv4AddressWithMask(int rawValue, int rawMask) {
         super(IPv4Address.of(rawValue), IPv4Address.of(rawMask));
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv6Address.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv6Address.java
index 001f185..ea71c65 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv6Address.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv6Address.java
@@ -16,6 +16,10 @@
     private final long raw1;
     private final long raw2;
 
+    private final static long NONE_VAL1 = 0x0L;
+    private final static long NONE_VAL2 = 0x0L;
+    public static final IPv6Address NONE = new IPv6Address(NONE_VAL1, NONE_VAL2);
+
     public static final IPv6Address NO_MASK = IPv6Address.of(0xFFFFFFFFFFFFFFFFl, 0xFFFFFFFFFFFFFFFFl);
     public static final IPv6Address FULL_MASK = IPv6Address.of(0x0, 0x0);
 
@@ -123,6 +127,8 @@
     }
 
     public static IPv6Address of(final long raw1, final long raw2) {
+        if(raw1==NONE_VAL1 && raw2 == NONE_VAL2)
+            return NONE;
         return new IPv6Address(raw1, raw2);
     }
 
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv6AddressWithMask.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv6AddressWithMask.java
index 16ff5b1..dcaa0b6 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv6AddressWithMask.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv6AddressWithMask.java
@@ -4,33 +4,34 @@
 import java.util.Arrays;
 
 public class IPv6AddressWithMask extends Masked<IPv6Address> {
+    public final static IPv6AddressWithMask NONE = of(IPv6Address.NONE, IPv6Address.NONE);
 
     private IPv6AddressWithMask(IPv6Address value, IPv6Address mask) {
         super(value, mask);
     }
-    
+
     public static IPv6AddressWithMask of(IPv6Address value, IPv6Address mask) {
         return new IPv6AddressWithMask(value, mask);
     }
-    
+
     @Override
     public String toString() {
         StringBuilder res = new StringBuilder();
-        res.append(((IPv6Address)value).toString());
+        res.append(value.toString());
         res.append('/');
-        
-        BigInteger maskint = new BigInteger(((IPv6Address)mask).getBytes());
+
+        BigInteger maskint = new BigInteger(mask.getBytes());
         if (maskint.not().add(BigInteger.ONE).bitCount() == 1) {
             // CIDR notation
             res.append(maskint.bitCount());
         } else {
             // Full address mask
-            res.append(((IPv6Address)mask).toString());
+            res.append(mask.toString());
         }
-        
+
         return res.toString();
     }
-    
+
     public static IPv6AddressWithMask of(final String string) {
         int slashPos;
         String ip = string;
@@ -58,10 +59,10 @@
                 throw new IllegalArgumentException("IPv6 Address not well formed: " + string);
             }
         }
-        
+
         // Read IP
         IPv6Address ipv6 = IPv6Address.of(ip);
-        
+
         if (maskAddress != null) {
             // Full address mask
             return IPv6AddressWithMask.of(ipv6, maskAddress);
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv6FlowLabel.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv6FlowLabel.java
index 7feb0d9..7dbf9bb 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv6FlowLabel.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv6FlowLabel.java
@@ -9,6 +9,9 @@
 
     private final int label;
 
+    private final static int NONE_VAL = 0x0;
+    public static final IPv6FlowLabel NONE = new IPv6FlowLabel(NONE_VAL);
+
     public static final IPv6FlowLabel NO_MASK = IPv6FlowLabel.of(0xFFFFFFFF);
     public static final IPv6FlowLabel FULL_MASK = IPv6FlowLabel.of(0x0);
 
@@ -17,6 +20,8 @@
     }
 
     public static IPv6FlowLabel of(int label) {
+        if(label == NONE_VAL)
+            return NONE;
         return new IPv6FlowLabel(label);
     }
 
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IpDscp.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IpDscp.java
index f311d9d..ec78315 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IpDscp.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IpDscp.java
@@ -72,6 +72,8 @@
 
     static final int LENGTH = 1;
 
+    public static final IpDscp NONE = DSCP_0;
+
     public static final IpDscp NO_MASK = DSCP_NO_MASK;
     public static final IpDscp FULL_MASK = DSCP_0;
 
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IpEcn.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IpEcn.java
index 5ecd251..7e1cdf0 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IpEcn.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IpEcn.java
@@ -10,6 +10,7 @@
     ECN_11((byte)3),
     ECN_NO_MASK((byte)0xFF);
 
+    public static final IpEcn NONE = ECN_00;
     public static final IpEcn NO_MASK = ECN_NO_MASK;
     public static final IpEcn FULL_MASK = ECN_00;
 
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IpProtocol.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IpProtocol.java
index e78c97b..36a76a2 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IpProtocol.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IpProtocol.java
@@ -4,7 +4,7 @@
 
 /**
  * IP-Protocol field representation
- * 
+ *
  * @author Yotam Harchol (yotam.harchol@bigswitch.com)
  */
 public class IpProtocol implements OFValueType<IpProtocol> {
@@ -298,6 +298,8 @@
     public static final IpProtocol IP_PROTO_HIP = new IpProtocol(IP_PROTO_NUM_HIP);
     public static final IpProtocol IP_PROTO_SHIM6 = new IpProtocol(IP_PROTO_NUM_SHIM6);
 
+    public static final IpProtocol NONE = IP_PROTO_HOPOPT;
+
     public static final IpProtocol NO_MASK = IP_PROTO_HOPOPT;
     public static final IpProtocol FULL_MASK = new IpProtocol((short)0x0000);
 
@@ -627,7 +629,7 @@
     public String toString() {
         return Integer.toHexString(proto);
     }
-    
+
     public void writeByte(ChannelBuffer c) {
         c.writeByte(this.proto);
     }
@@ -644,5 +646,5 @@
     public short getIpProtocolNumber() {
         return proto;
     }
-    
+
 }
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/MacAddress.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/MacAddress.java
index 040d875..cc047ca 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/MacAddress.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/MacAddress.java
@@ -14,6 +14,9 @@
     static final int MacAddrLen = 6;
     private final long rawValue;
 
+    private final static long NONE_VAL = 0x0L;
+    public static final MacAddress NONE = new MacAddress(NONE_VAL);
+
     public static final MacAddress NO_MASK = MacAddress.of(0xFFFFFFFFFFFFFFFFl);
     public static final MacAddress FULL_MASK = MacAddress.of(0x0);
 
@@ -30,6 +33,9 @@
     }
 
     public static MacAddress of(final long raw) {
+        if(raw == NONE_VAL)
+            return NONE;
+
         return new MacAddress(raw);
     }
 
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/Metadata.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/Metadata.java
index 1d0aea7..e4eed77 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/Metadata.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/Metadata.java
@@ -5,6 +5,10 @@
 @Immutable
 public class Metadata {
     static final int LENGTH = 4;
+
+    private final static int NONE_VAL = 0;
+    public final static Metadata NONE = new Metadata(NONE_VAL);
+
     private final int rawValue;
 
     private Metadata(final int rawValue) {
@@ -12,6 +16,9 @@
     }
 
     public static Metadata of(final int raw) {
+        if(raw == NONE_VAL)
+            return NONE;
+
         return new Metadata(raw);
     }
 
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/OFMetadata.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/OFMetadata.java
index 861d4a8..766ade1 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/OFMetadata.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/OFMetadata.java
@@ -8,6 +8,8 @@
 
     private final U64 u64;
 
+    public static final OFMetadata NONE = OFMetadata.of(U64.ZERO);
+
     public static final OFMetadata NO_MASK = OFMetadata.of(U64.ofRaw(0xFFFFFFFFFFFFFFFFl));
     public static final OFMetadata FULL_MASK = OFMetadata.of(U64.ofRaw(0x0));
 
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/OFPhysicalPort.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/OFPhysicalPort.java
deleted file mode 100644
index ca662f7..0000000
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/OFPhysicalPort.java
+++ /dev/null
@@ -1,90 +0,0 @@
-package org.projectfloodlight.openflow.types;
-
-import org.jboss.netty.buffer.ChannelBuffer;
-import org.projectfloodlight.openflow.exceptions.OFParseError;
-import org.projectfloodlight.openflow.protocol.OFMessageReader;
-import org.projectfloodlight.openflow.protocol.Writeable;
-
-/**
- * A wrapper around the OpenFlow physical port description. The interfaces to
- * this object are version agnostic.
- *
- * @author capveg
- */
-
-public class OFPhysicalPort implements OFValueType<OFPhysicalPort>, Writeable {
-
-    static final int LENGTH = 4;
-
-    private final int port;
-
-    public static final OFPhysicalPort NO_MASK = OFPhysicalPort.of(0xFFFFFFFF);
-    public static final OFPhysicalPort FULL_MASK = OFPhysicalPort.of(0x0);
-
-    private OFPhysicalPort(int port) {
-        this.port = port;
-    }
-
-    public static OFPhysicalPort of(int port) {
-        return new OFPhysicalPort(port);
-    }
-
-    @Override
-    public int getLength() {
-        return LENGTH;
-    }
-
-    @Override
-    public boolean equals(Object obj) {
-        if (!(obj instanceof OFPhysicalPort))
-            return false;
-        OFPhysicalPort other = (OFPhysicalPort)obj;
-        if (other.port != this.port)
-            return false;
-        return true;
-    }
-
-    @Override
-    public int hashCode() {
-        final int prime = 59;
-        int result = 1;
-        result = prime * result + port;
-        return result;
-    }
-
-    @Override
-    public String toString() {
-        return Integer.toHexString(port);
-    }
-
-    public void write4Bytes(ChannelBuffer c) {
-        c.writeInt(this.port);
-    }
-
-    @Override
-    public void writeTo(ChannelBuffer bb) {
-        write4Bytes(bb);
-    }
-
-    public static OFPhysicalPort read4Bytes(ChannelBuffer c) throws OFParseError {
-        return OFPhysicalPort.of((int)(c.readUnsignedInt() & 0xFFFFFFFF));
-    }
-
-    @Override
-    public OFPhysicalPort applyMask(OFPhysicalPort mask) {
-        return OFPhysicalPort.of(this.port & mask.port);
-    }
-
-    public int getPortNumber() {
-        return port;
-    }
-
-    public final static Reader READER = new Reader();
-    private static class Reader implements OFMessageReader<OFPhysicalPort> {
-        @Override
-        public OFPhysicalPort readFrom(ChannelBuffer bb) throws OFParseError {
-            return OFPhysicalPort.read4Bytes(bb);
-        }
-
-    }
-}
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/OFPort.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/OFPort.java
index d65d0aa..db7bd5f 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/OFPort.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/OFPort.java
@@ -17,9 +17,10 @@
 @Immutable
 public class OFPort implements OFValueType<OFPort> {
     static final int LENGTH = 4;
-    
+
     // private int constants (OF1.1+) to avoid duplication in the code
     // should not have to use these outside this class
+    private static final int OFPP_NONE_INT = 0x0;
     private static final int OFPP_ANY_INT = 0xFFffFFff;
     private static final int OFPP_LOCAL_INT = 0xFFffFFfe;
     private static final int OFPP_CONTROLLER_INT = 0xFFffFFfd;
@@ -86,9 +87,12 @@
      */
     public final static OFPort ANY = new NamedPort(OFPP_ANY_INT, "any");
 
+    /** port number 0, read of the wire, e.g, if not set */
+    public final static OFPort NONE = new NamedPort(OFPP_NONE_INT, "none");
+
     public static final OFPort NO_MASK = OFPort.of(0xFFFFFFFF);
     public static final OFPort FULL_MASK = OFPort.of(0x0);
-    
+
     /** cache of frequently used ports */
     private static class PrecachedPort {
         private final static OFPort p1 = new OFPort(1);
@@ -158,6 +162,8 @@
      */
     public static OFPort ofInt(final int portNumber) {
         switch (portNumber) {
+            case 0:
+                return NONE;
             case 1:
                 return PrecachedPort.p1;
             case 2:
@@ -300,6 +306,8 @@
      */
     public static OFPort ofShort(final short portNumber) {
         switch (portNumber) {
+            case 0:
+                return NONE;
             case 1:
                 return PrecachedPort.p1;
             case 2:
@@ -499,7 +507,7 @@
     public int getLength() {
         return LENGTH;
     }
-    
+
     @Override
     public boolean equals(Object obj) {
         if (!(obj instanceof OFPort))
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/TransportPort.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/TransportPort.java
index 4cf5b90..6efd813 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/TransportPort.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/TransportPort.java
@@ -14,6 +14,9 @@
     static final int MAX_PORT = 0xFFFF;
     static final int MIN_PORT = 0;
 
+    private final static int NONE_VAL = 0;
+    public final static TransportPort NONE = new TransportPort(NONE_VAL);
+
     public static final TransportPort NO_MASK = new TransportPort(0xFFFFFFFF);
     public static final TransportPort FULL_MASK = TransportPort.of(0x0);
 
@@ -24,7 +27,9 @@
     }
 
     public static TransportPort of(int port) {
-        if (port < MIN_PORT || port > MAX_PORT) {
+        if(port == NONE_VAL)
+            return NONE;
+        else if (port < MIN_PORT || port > MAX_PORT) {
             throw new IllegalArgumentException("Illegal transport layer port number: " + port);
         }
         return new TransportPort(port);
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/U16.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/U16.java
index 55a467e..43bec7a 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/U16.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/U16.java
@@ -23,6 +23,9 @@
 import org.projectfloodlight.openflow.protocol.Writeable;
 
 public class U16 implements Writeable, OFValueType<U16> {
+    private final static short ZERO_VAL = 0;
+    public final static U16 ZERO = new U16(ZERO_VAL);
+
     public static int f(final short i) {
         return i & 0xffff;
     }
@@ -38,11 +41,13 @@
     }
 
     public static final U16 of(int value) {
-        return new U16(t(value));
+        return ofRaw(t(value));
     }
 
-    public static final U16 ofRaw(short value) {
-        return new U16(value);
+    public static final U16 ofRaw(short raw) {
+        if(raw == ZERO_VAL)
+            return ZERO;
+        return new U16(raw);
     }
 
     public int getValue() {
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/U32.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/U32.java
index 2634ed1..f56a528 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/U32.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/U32.java
@@ -23,6 +23,9 @@
 import org.projectfloodlight.openflow.protocol.Writeable;
 
 public class U32 implements Writeable, OFValueType<U32> {
+    private final static int ZERO_VAL = 0;
+    public final static U32 ZERO = new U32(ZERO_VAL);
+
     private final int raw;
 
     private U32(int raw) {
@@ -30,11 +33,13 @@
     }
 
     public static U32 of(long value) {
-        return new U32(U32.t(value));
+        return ofRaw(U32.t(value));
     }
 
-    public static U32 ofRaw(int value) {
-        return new U32(value);
+    public static U32 ofRaw(int raw) {
+        if(raw == ZERO_VAL)
+            return ZERO;
+        return new U32(raw);
     }
 
     public long getValue() {
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/U64.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/U64.java
index 5de62dc..3b89e24 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/U64.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/U64.java
@@ -24,6 +24,8 @@
 
 public class U64 implements Writeable, OFValueType<U64> {
     private static final long UNSIGNED_MASK = 0x7fffffffffffffffL;
+    private final static long ZERO_VAL = 0;
+    public final static U64 ZERO = new U64(ZERO_VAL);
 
     private final long raw;
 
@@ -36,6 +38,8 @@
     }
 
     public static U64 ofRaw(final long raw) {
+        if(raw == ZERO_VAL)
+            return ZERO;
         return new U64(raw);
     }
 
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/U8.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/U8.java
index 41e740e..f85bfae 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/U8.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/U8.java
@@ -23,6 +23,9 @@
 import org.projectfloodlight.openflow.protocol.Writeable;
 
 public class U8 implements Writeable, OFValueType<U8> {
+    private final static byte ZERO_VAL = 0;
+    public final static U8 ZERO = new U8(ZERO_VAL);
+
     private final byte raw;
 
     private U8(byte raw) {
@@ -30,6 +33,9 @@
     }
 
     public static final U8 of(short value) {
+        if(value == ZERO_VAL)
+            return ZERO;
+
         return new U8(t(value));
     }
 
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/VlanPcp.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/VlanPcp.java
index f6993fe..7d15fb7 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/VlanPcp.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/VlanPcp.java
@@ -6,10 +6,12 @@
 public class VlanPcp implements OFValueType<VlanPcp> {
 
     private static final byte VALIDATION_MASK = 0x07;
+    private static final byte NONE_VAL = 0x00;
     static final int LENGTH = 1;
 
     private final byte pcp;
 
+    public static final VlanPcp NONE = new VlanPcp(NONE_VAL);
     public static final VlanPcp NO_MASK = new VlanPcp((byte)0xFF);
     public static final VlanPcp FULL_MASK = VlanPcp.of((byte)0x0);
 
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/VlanVid.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/VlanVid.java
index 63b8831..5c23779 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/VlanVid.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/VlanVid.java
@@ -6,8 +6,10 @@
 public class VlanVid implements OFValueType<VlanVid> {
 
     private static final short VALIDATION_MASK = 0x0FFF;
+    private static final short NONE_VAL = 0x0000;
     final static int LENGTH = 2;
 
+    public static final VlanVid NONE = new VlanVid(NONE_VAL);
     public static final VlanVid NO_MASK = new VlanVid((short)0xFFFF);
     public static final VlanVid FULL_MASK = VlanVid.of((short)0x0);
 
@@ -18,7 +20,9 @@
     }
 
     public static VlanVid of(short vid) {
-        if ((vid & VALIDATION_MASK) != vid)
+        if(vid == NONE_VAL)
+            return NONE;
+        else if ((vid & VALIDATION_MASK) != vid)
             throw new IllegalArgumentException("Illegal VLAN VID value: " + vid);
         return new VlanVid(vid);
     }