--- a/src/internet-node/tcp-header.h	Mon Mar 17 12:12:17 2008 -0700
+++ b/src/internet-node/tcp-header.h	Mon Mar 17 13:12:17 2008 -0700
@@ -30,8 +30,11 @@
 
 namespace ns3 {
 
-class TcpHeader : public Header {
+class TcpHeader : public Header 
+{
 public:
+  static TypeId GetTypeId (void);
+  virtual TypeId GetInstanceTypeId (void) const;
   static uint32_t GetUid (void);
 
   TcpHeader ();
@@ -138,9 +141,9 @@
 
   std::string GetName (void) const;
   void Print (std::ostream &os) const;
-  uint32_t GetSerializedSize (void) const;
-  void Serialize (Buffer::Iterator start) const;
-  uint32_t Deserialize (Buffer::Iterator start);
+  virtual uint32_t GetSerializedSize (void) const;
+  virtual void Serialize (Buffer::Iterator start) const;
+  virtual uint32_t Deserialize (Buffer::Iterator start);
 
 private:
   uint16_t m_sourcePort;