add Application::SetNode and NetDevice::SetNode, use them from Node::AddApplication and Node::AddDevice. kill useless "Node" attributes.

src/node/application.cc

@@ -40,10 +40,6 @@ Application::GetTypeId (void)
 {
   static TypeId tid = TypeId ("Application")
     .SetParent<Object> ()
-    .AddAttribute ("Node", "The on which this application resides",
-                   Ptr<Node> (0),
-                   MakePtrAccessor (&Application::m_node),
-                   MakePtrChecker<Node> ())
     ;
   return tid;
 }
@@ -92,6 +88,12 @@ Ptr<Node> Application::GetNode() const
   return m_node;
 }
 
+void 
+Application::SetNode (Ptr<Node> node)
+{
+  m_node = node;
+}
+
 // Protected methods
 // StartApp and StopApp will likely be overridden by application subclasses
 void Application::StartApplication()

src/node/application.h

@@ -102,6 +102,8 @@ public:
    * \returns the Node to which this Application object is attached.
    */
   Ptr<Node> GetNode() const;
+
+  void SetNode (Ptr<Node> node);
   
 private:
   /**

src/node/net-device.h

@@ -221,6 +221,8 @@ public:
    */
   virtual Ptr<Node> GetNode (void) const = 0;
 
+  virtual void SetNode (Ptr<Node> node) = 0;
+
   /**
    * \returns true if ARP is needed, false otherwise.
    *

src/node/node.cc

@@ -96,6 +96,7 @@ Node::AddDevice (Ptr<NetDevice> device)
 {
   uint32_t index = m_devices.size ();
   m_devices.push_back (device);
+  device->SetNode (this);
   device->SetIfIndex(index);
   device->SetReceiveCallback (MakeCallback (&Node::ReceiveFromDevice, this));
   NotifyDeviceAdded (device);
@@ -117,6 +118,7 @@ Node::AddApplication (Ptr<Application> application)
 {
   uint32_t index = m_applications.size ();
   m_applications.push_back (application);
+  application->SetNode (this);
   return index;
 }
 Ptr<Application>