--- a/SConstruct	Thu May 03 14:23:41 2007 +0200
+++ b/SConstruct	Thu May 03 14:39:37 2007 +0200
@@ -223,6 +223,7 @@
     'ipv4-end-point-demux.cc',
     'i-udp.cc',
     'i-udp-impl.cc',
+    'i-arp-private.cc',
     ])
 node.add_headers ([
     'ipv4-header.h',
@@ -243,6 +244,7 @@
     'udp-socket.h',
     'i-udp-impl.h',
     'udp.h',
+    'i-arp-private.h',
     ])
 node.add_inst_headers ([
     'node.h',

--- a/src/node/arp-ipv4-interface.cc	Thu May 03 14:23:41 2007 +0200
+++ b/src/node/arp-ipv4-interface.cc	Thu May 03 14:39:37 2007 +0200
@@ -24,7 +24,7 @@
 #include "ns3/composite-trace-resolver.h"
 
 #include "arp-ipv4-interface.h"
-#include "arp.h"
+#include "i-arp-private.h"
 #include "node.h"
 #include "net-device.h"
 #include "ipv4.h"
@@ -62,7 +62,7 @@
   NS_ASSERT (PeekDevice () != 0);
   if (PeekDevice ()->NeedsArp ())
     {
-      Arp * arp = m_node->GetArp ();
+      IArpPrivate * arp = m_node->QueryInterface<IArpPrivate> (IArpPrivate::iid);
       MacAddress hardwareDestination;
       bool found = arp->Lookup (p, dest, PeekDevice (), &hardwareDestination);
       if (found)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/node/i-arp-private.cc	Thu May 03 14:39:37 2007 +0200
@@ -0,0 +1,58 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2007 INRIA
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Author: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
+ */
+#include "i-arp-private.h"
+#include "ns3/iid-manager.h"
+#include "arp.h"
+#include "ns3/assert.h"
+
+namespace ns3 {
+
+const uint32_t IArpPrivate::iid = IidManager::Allocate ("IArpPrivate");
+
+IArpPrivate::IArpPrivate (Arp *arp)
+  : NsUnknown (IArpPrivate::iid),
+    m_arp (arp)
+{
+  m_arp->Ref ();
+}
+IArpPrivate::~IArpPrivate ()
+{
+  NS_ASSERT (m_arp == 0);
+}
+
+bool 
+IArpPrivate::Lookup (Packet &p, Ipv4Address destination, 
+		     NetDevice *device,
+		     MacAddress *hardwareDestination)
+{
+  return m_arp->Lookup (p, destination, device, hardwareDestination);
+}
+
+void
+IArpPrivate::DoDispose (void)
+{
+  m_arp->Unref ();
+  m_arp = 0;
+  NsUnknown::DoDispose ();
+}
+
+
+} // namespace ns3

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/node/i-arp-private.h	Thu May 03 14:39:37 2007 +0200
@@ -0,0 +1,51 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2007 INRIA
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Author: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
+ */
+#ifndef I_ARP_PRIVATE_H
+#define I_ARP_PRIVATE_H
+
+#include "ns3/ns-unknown.h"
+#include "ipv4-address.h"
+
+namespace ns3 {
+
+class NetDevice;
+class MacAddress;
+class Packet;
+class Arp;
+
+class IArpPrivate : public NsUnknown
+{
+public:
+  static const uint32_t iid;
+  IArpPrivate (Arp *arp);
+  virtual ~IArpPrivate ();
+  bool Lookup (Packet &p, Ipv4Address destination, 
+	       NetDevice *device,
+	       MacAddress *hardwareDestination);
+protected:
+  virtual void DoDispose (void);
+private:
+  Arp *m_arp;
+};
+
+} // namespace ns3
+
+#endif /* I_ARP_PRIVATE_H */

--- a/src/node/internet-node.cc	Thu May 03 14:23:41 2007 +0200
+++ b/src/node/internet-node.cc	Thu May 03 14:39:37 2007 +0200
@@ -32,6 +32,7 @@
 #include "arp.h"
 #include "net-device.h"
 #include "i-udp-impl.h"
+#include "i-arp-private.h"
 
 namespace ns3 {
 
@@ -42,8 +43,6 @@
   Arp *arp = new Arp (this);
   Udp *udp = new Udp (this);
 
-
-  // Instantiate the capabilities
   ApplicationList *applicationList = new ApplicationList(this);
   L3Demux *l3Demux = new L3Demux(this);
   Ipv4L4Demux *ipv4L4Demux = new Ipv4L4Demux(this);
@@ -53,7 +52,9 @@
   ipv4L4Demux->Insert (udp);
 
   IUdpImpl *udpImpl = new IUdpImpl (udp);
+  IArpPrivate *arpPrivate = new IArpPrivate (arp);
 
+  NsUnknown::AddInterface (arpPrivate);
   NsUnknown::AddInterface (udpImpl);
   NsUnknown::AddInterface (applicationList);
   NsUnknown::AddInterface (l3Demux);
@@ -67,6 +68,7 @@
   arp->Unref ();
   udp->Unref ();
   udpImpl->Unref ();
+  arpPrivate->Unref ();
 }
 
 InternetNode::~InternetNode ()
@@ -88,11 +90,6 @@
                  InternetNode::IPV4);
   ipv4->Unref ();
 
-  Arp *arp = GetArp ();
-  resolver->Add ("arp",
-                 MakeCallback (&Arp::CreateTraceResolver, arp),
-                 InternetNode::ARP);
-  arp->Unref ();
 
   return resolver;
 }
@@ -113,16 +110,6 @@
   return ipv4;
 }
 
-Arp *
-InternetNode::GetArp (void) const
-{
-  L3Demux *l3Demux = QueryInterface<L3Demux> (L3Demux::iid);
-  Arp *arp = static_cast<Arp*> (l3Demux->PeekProtocol (Arp::PROT_NUMBER));
-  l3Demux->Unref ();
-  arp->Ref ();
-  return arp;
-}
-
 void 
 InternetNode::DoAddDevice (NetDevice *device) const
 {

--- a/src/node/internet-node.h	Thu May 03 14:23:41 2007 +0200
+++ b/src/node/internet-node.h	Thu May 03 14:39:37 2007 +0200
@@ -38,14 +38,12 @@
 public:
   enum TraceType {
     IPV4,
-    ARP,
   };
   InternetNode();
   virtual ~InternetNode ();
   virtual TraceResolver *CreateTraceResolver (TraceContext const &context);
   // Capability access
   virtual Ipv4 *           GetIpv4 (void) const;
-  virtual Arp *            GetArp (void) const;
 
   void SetName(std::string name);
 protected:

--- a/src/node/node.cc	Thu May 03 14:23:41 2007 +0200
+++ b/src/node/node.cc	Thu May 03 14:39:37 2007 +0200
@@ -108,10 +108,4 @@
   return 0;
 }
 
-Arp *
-Node::GetArp (void) const
-{
-  return 0;
-}
-
 }//namespace ns3

--- a/src/node/node.h	Thu May 03 14:23:41 2007 +0200
+++ b/src/node/node.h	Thu May 03 14:39:37 2007 +0200
@@ -32,7 +32,6 @@
 namespace ns3 {
 
 class Ipv4;
-class Arp;
 
 class TraceContext;
 class TraceResolver;
@@ -71,7 +70,6 @@
   // of the correct type if one exists, or the nil pointer if no
   // null capability exists.
   virtual Ipv4 *           GetIpv4 (void) const;
-  virtual Arp *            GetArp (void) const;
   
 private:
   uint32_t    m_id;         // Node id for this node