diff --git a/apps/ndn-app.h b/apps/ndn-app.h
index 57d1d83..491cae4 100644
--- a/apps/ndn-app.h
+++ b/apps/ndn-app.h
@@ -35,9 +35,6 @@
 class Interest;
 class ContentObject;
 
-typedef Interest InterestHeader;
-typedef ContentObject ContentObjectHeader;
-
 class Face;
 
 /**
@@ -52,7 +49,8 @@
   /**
    * @brief A callback to pass packets to underlying NDN protocol
    */
-  typedef Callback<bool, const Ptr<const Packet>&> ProtocolHandler;
+  typedef Callback<bool, Ptr<const Interest>, Ptr<const Packet> > InterestHandler;
+  typedef Callback<bool, Ptr<const ContentObject>, Ptr<const Packet> > DataHandler;
   
   static TypeId GetTypeId ();
 
@@ -63,12 +61,6 @@
   virtual ~App ();
 
   /**
-   * @brief Register lower layer callback (to send interests from the application)
-   */
-  void
-  RegisterProtocolHandler (ProtocolHandler handler);
-
-  /**
    * @brief Get application ID (ID of applications face)
    */
   uint32_t
@@ -114,7 +106,6 @@
   StopApplication ();     ///< @brief Called at time specified by Stop
 
 protected:
-  ProtocolHandler m_protocolHandler; ///< @brief A callback to pass packets to underlying NDN protocol
   bool m_active;  ///< @brief Flag to indicate that application is active (set by StartApplication and StopApplication)
   Ptr<Face> m_face;   ///< @brief automatically created application face through which application communicates