diff --git a/helper/tracers/ccnx-aggregate-app-tracer.cc b/helper/tracers/ccnx-aggregate-app-tracer.cc
new file mode 100644
index 0000000..6129e8c
--- /dev/null
+++ b/helper/tracers/ccnx-aggregate-app-tracer.cc
@@ -0,0 +1,172 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2011 UCLA
+ *
+ * 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:  Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ */
+
+#include "ccnx-aggregate-app-tracer.h"
+#include "ns3/node.h"
+#include "ns3/packet.h"
+#include "ns3/config.h"
+#include "ns3/callback.h"
+#include "ns3/ccnx-app.h"
+#include "ns3/ccnx-face.h"
+#include "ns3/ccnx-interest-header.h"
+#include "ns3/ccnx-content-object-header.h"
+
+namespace ns3 {
+    
+CcnxAggregateAppTracer::CcnxAggregateAppTracer (const std::string &app, Ptr<Node> node, const std::string &appId)
+  : CcnxAppTracer (app, node, appId)
+  , m_inInterests (0)
+  , m_outInterests (0)
+  , m_inNacks (0)
+  , m_inData (0)
+  , m_outData (0)
+
+  , m_inInterestsBytes (0)
+  , m_outInterestsBytes (0)
+  , m_inNacksBytes (0)
+  , m_inDataBytes (0)
+  , m_outDataBytes (0)
+{
+}
+
+CcnxAggregateAppTracer::CcnxAggregateAppTracer (const std::string &app, const std::string &node, const std::string &appId)
+  : CcnxAppTracer (app, node, appId)
+  , m_inInterests (0)
+  , m_outInterests (0)
+  , m_inNacks (0)
+  , m_inData (0)
+  , m_outData (0)
+
+  , m_inInterestsBytes (0)
+  , m_outInterestsBytes (0)
+  , m_inNacksBytes (0)
+  , m_inDataBytes (0)
+  , m_outDataBytes (0)
+{
+}
+
+void
+CcnxAggregateAppTracer::Reset ()
+{
+  m_inInterests = 0;
+  m_outInterests = 0;
+  m_inNacks = 0;
+  m_inData = 0;
+  m_outData = 0;
+
+  m_inInterestsBytes = 0;
+  m_outInterestsBytes = 0;
+  m_inNacksBytes = 0;
+  m_inDataBytes = 0;
+  m_outDataBytes = 0;
+}
+
+void
+CcnxAggregateAppTracer::PrintHeader (std::ostream &os) const
+{
+  os << "NodeId" << "\t"
+     << "App" << "\t"
+     << "AppId" << "\t"
+     << "InInterests" << "\t"
+     << "OutInterests" << "\t"
+    
+     << "InNacks" << "\t"
+    
+     << "InData" << "\t"
+     << "OutData" << "\t"
+
+     << "InInterestsBytes" << "\t"
+     << "OutInterestsBytes" << "\t"
+    
+     << "InNacksBytes" << "\t"
+    
+     << "InDataBytes" << "\t"
+     << "OutDataBytes";
+}
+
+void
+CcnxAggregateAppTracer::Print (std::ostream &os) const
+{
+  os << m_node << "\t"
+     << m_app << "\t"
+     << m_appId << "\t"
+
+     << m_inInterests << "\t"
+     << m_outInterests << "\t"
+    
+     << m_inNacks << "\t"
+    
+     << m_inData << "\t"
+     << m_outData << "\t"
+
+     << m_inInterestsBytes << "\t"
+     << m_outInterestsBytes << "\t"
+    
+     << m_inNacksBytes << "\t"
+    
+     << m_inDataBytes << "\t"
+     << m_outDataBytes;
+}
+
+void
+CcnxAggregateAppTracer::OutInterests (std::string context,
+                                      Ptr<const CcnxInterestHeader> header, Ptr<CcnxApp>, Ptr<CcnxFace>)
+{
+  m_outInterests++;
+  m_outInterestsBytes += header->GetSerializedSize ();
+}
+
+void
+CcnxAggregateAppTracer::OutData (std::string context,
+                                 Ptr<const CcnxContentObjectHeader> header, Ptr<const Packet> payload,
+                                 Ptr<CcnxApp>, Ptr<CcnxFace>)
+{
+  m_outData++;
+  m_outDataBytes += header->GetSerializedSize () + payload->GetSerializedSize ();
+}
+
+void
+CcnxAggregateAppTracer::InInterests (std::string context,
+                                     Ptr<const CcnxInterestHeader> header,
+                                     Ptr<CcnxApp>, Ptr<CcnxFace>)
+{
+  m_inInterests++;
+  m_inInterestsBytes += header->GetSerializedSize ();
+}
+
+void
+CcnxAggregateAppTracer::InNacks (std::string context,
+                                 Ptr<const CcnxInterestHeader> header,
+                                 Ptr<CcnxApp>, Ptr<CcnxFace>)
+{
+  m_inNacks++;
+  m_inNacksBytes += header->GetSerializedSize ();
+}
+  
+void
+CcnxAggregateAppTracer::InData (std::string context,
+                                Ptr<const CcnxContentObjectHeader> header, Ptr<const Packet> payload,
+                                Ptr<CcnxApp>, Ptr<CcnxFace>)
+{
+  m_inData++;
+  m_inDataBytes += header->GetSerializedSize () + payload->GetSerializedSize ();
+}
+
+} // namespace ns3
diff --git a/helper/tracers/ccnx-aggregate-app-tracer.h b/helper/tracers/ccnx-aggregate-app-tracer.h
new file mode 100644
index 0000000..e321b64
--- /dev/null
+++ b/helper/tracers/ccnx-aggregate-app-tracer.h
@@ -0,0 +1,81 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2011 UCLA
+ *
+ * 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:  Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ */
+
+#ifndef CCNX_AGGREGATE_APP_TRACER_H
+#define CCNX_AGGREGATE_APP_TRACER_H
+
+#include "ns3/ccnx-app-tracer.h"
+
+namespace ns3 {
+
+class CcnxAggregateAppTracer : public CcnxAppTracer
+{
+public:
+  CcnxAggregateAppTracer (const std::string &app, Ptr<Node> node, const std::string &appId = "*");
+  CcnxAggregateAppTracer (const std::string &app, const std::string &node, const std::string &appId = "*");
+  virtual ~CcnxAggregateAppTracer () { };
+
+  virtual void
+  PrintHeader (std::ostream &os) const;
+
+  virtual void
+  Print (std::ostream &os) const;
+
+  virtual void
+  OutInterests (std::string context,
+                Ptr<const CcnxInterestHeader>, Ptr<CcnxApp>, Ptr<CcnxFace>);
+
+  virtual void
+  InInterests  (std::string context,
+                Ptr<const CcnxInterestHeader>, Ptr<CcnxApp>, Ptr<CcnxFace>);
+
+  virtual void
+  InNacks (std::string context,
+           Ptr<const CcnxInterestHeader>, Ptr<CcnxApp>, Ptr<CcnxFace>);
+
+  virtual void
+  OutData (std::string context,
+           Ptr<const CcnxContentObjectHeader>, Ptr<const Packet>, Ptr<CcnxApp>, Ptr<CcnxFace>);
+  
+  virtual void
+  InData  (std::string context,
+           Ptr<const CcnxContentObjectHeader>, Ptr<const Packet>, Ptr<CcnxApp>, Ptr<CcnxFace>);
+
+protected:
+  void
+  Reset ();
+
+protected:
+  uint64_t m_inInterests;
+  uint64_t m_outInterests;
+  uint64_t m_inNacks;
+  uint64_t m_inData; 
+  uint64_t m_outData;
+
+  uint64_t m_inInterestsBytes;
+  uint64_t m_outInterestsBytes;
+  uint64_t m_inNacksBytes;
+  uint64_t m_inDataBytes;
+  uint64_t m_outDataBytes;
+};
+
+} // namespace ns3
+
+#endif // CCNX_AGGREGATE_APP_TRACER_H
diff --git a/helper/tracers/ccnx-aggregate-l3-tracer.cc b/helper/tracers/ccnx-aggregate-l3-tracer.cc
new file mode 100644
index 0000000..596f036
--- /dev/null
+++ b/helper/tracers/ccnx-aggregate-l3-tracer.cc
@@ -0,0 +1,201 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2011 UCLA
+ *
+ * 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:  Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ */
+
+#include "ccnx-aggregate-l3-tracer.h"
+#include "ns3/node.h"
+#include "ns3/packet.h"
+#include "ns3/config.h"
+#include "ns3/callback.h"
+#include "ns3/ccnx-app.h"
+#include "ns3/ccnx-face.h"
+#include "ns3/ccnx-interest-header.h"
+#include "ns3/ccnx-content-object-header.h"
+
+namespace ns3 {
+    
+CcnxAggregateL3Tracer::CcnxAggregateL3Tracer (Ptr<Node> node)
+  : CcnxL3Tracer (node)
+{
+  Reset ();
+}
+
+CcnxAggregateL3Tracer::CcnxAggregateL3Tracer (const std::string &node)
+  : CcnxL3Tracer (node)
+{
+  Reset ();
+}
+
+void
+CcnxAggregateL3Tracer::Stats::Reset ()
+{
+  m_inInterests = 0;
+  m_outInterests = 0;
+  m_dropInterests = 0;
+  m_inNacks = 0;
+  m_outNacks = 0;
+  m_dropNacks = 0;
+  m_inData = 0;
+  m_outData = 0;
+  m_dropData = 0;
+}
+
+
+void
+CcnxAggregateL3Tracer::Reset ()
+{
+  m_packets.Reset ();
+  m_bytes.Reset ();
+}
+
+
+void
+CcnxAggregateL3Tracer::PrintHeader (std::ostream &os) const
+{
+  os << "Node" << "\t"
+     << "InInterests" << "\t"
+     << "OutInterests" << "\t"
+     << "DropInterests" << "\t"
+    
+     << "InNacks" << "\t"
+     << "OutNacks" << "\t"
+     << "DropNacks" << "\t"
+    
+     << "InData" << "\t"
+     << "OutData" << "\t"
+     << "DropData" << "\t"
+    
+     << "InInterestsBytes" << "\t"
+     << "OutInterestsBytes" << "\t"
+     << "DropInterestsBytes" << "\t"
+    
+     << "InNacksBytes" << "\t"
+     << "OutNacksBytes" << "\t"
+     << "DropNacksBytes" << "\t"
+    
+     << "InDataBytes" << "\t"
+     << "OutDataBytes" << "\t"
+     << "DropDataBytes";
+}
+
+void
+CcnxAggregateL3Tracer::Print (std::ostream &os) const
+{
+  os << m_node << "\t"
+     << m_packets.m_inInterests   << "\t"
+     << m_packets.m_outInterests  << "\t"
+     << m_packets.m_dropInterests << "\t"
+
+     << m_packets.m_inNacks   << "\t"
+     << m_packets.m_outNacks  << "\t"
+     << m_packets.m_dropNacks << "\t"
+
+     << m_packets.m_inData   << "\t"
+     << m_packets.m_outData  << "\t"
+     << m_packets.m_dropData << "\t"
+
+     << m_bytes.m_inInterests   << "\t"
+     << m_bytes.m_outInterests  << "\t"
+     << m_bytes.m_dropInterests << "\t"
+
+     << m_bytes.m_inNacks   << "\t"
+     << m_bytes.m_outNacks  << "\t"
+     << m_bytes.m_dropNacks << "\t"
+
+     << m_bytes.m_inData   << "\t"
+     << m_bytes.m_outData  << "\t"
+     << m_bytes.m_dropData;
+}
+
+void
+CcnxAggregateL3Tracer::OutInterests  (std::string context,
+                                      Ptr<const CcnxInterestHeader> header, Ptr<const CcnxFace>)
+{
+  m_packets.m_outInterests++;
+  m_bytes.m_outInterests += header->GetSerializedSize ();
+}
+
+void
+CcnxAggregateL3Tracer::InInterests   (std::string context,
+                                      Ptr<const CcnxInterestHeader> header, Ptr<const CcnxFace>)
+{
+  m_packets.m_inInterests++;
+  m_bytes.m_inInterests += header->GetSerializedSize ();
+}
+
+void
+CcnxAggregateL3Tracer::DropInterests (std::string context,
+                                      Ptr<const CcnxInterestHeader> header, Ccnx::DropReason, Ptr<const CcnxFace>)
+{
+  m_packets.m_dropInterests++;
+  m_bytes.m_dropInterests += header->GetSerializedSize ();
+}
+
+void
+CcnxAggregateL3Tracer::OutNacks  (std::string context,
+                                  Ptr<const CcnxInterestHeader> header, Ptr<const CcnxFace>)
+{
+  m_packets.m_outNacks++;
+  m_bytes.m_outNacks += header->GetSerializedSize ();
+}
+
+void
+CcnxAggregateL3Tracer::InNacks   (std::string context,
+                                  Ptr<const CcnxInterestHeader> header, Ptr<const CcnxFace>)
+{
+  m_packets.m_inNacks++;
+  m_bytes.m_inNacks += header->GetSerializedSize ();
+}
+
+void
+CcnxAggregateL3Tracer::DropNacks (std::string context,
+                                  Ptr<const CcnxInterestHeader> header, Ccnx::DropReason, Ptr<const CcnxFace>)
+{
+  m_packets.m_dropNacks++;
+  m_bytes.m_dropNacks += header->GetSerializedSize ();
+}
+
+void
+CcnxAggregateL3Tracer::OutData  (std::string context,
+                                 Ptr<const CcnxContentObjectHeader> header, Ptr<const Packet> payload,
+                                 bool fromCache, Ptr<const CcnxFace>)
+{
+  m_packets.m_outData++;
+  m_bytes.m_outData += header->GetSerializedSize () + payload->GetSize ();
+}
+
+void
+CcnxAggregateL3Tracer::InData   (std::string context,
+                                 Ptr<const CcnxContentObjectHeader> header, Ptr<const Packet> payload,
+                                 Ptr<const CcnxFace>)
+{
+  m_packets.m_inData++;
+  m_bytes.m_inData += header->GetSerializedSize () + payload->GetSize ();
+}
+
+void
+CcnxAggregateL3Tracer::DropData (std::string context,
+                                 Ptr<const CcnxContentObjectHeader> header, Ptr<const Packet> payload,
+                                 Ccnx::DropReason, Ptr<const CcnxFace>)
+{
+  m_packets.m_dropData++;
+  m_bytes.m_dropData += header->GetSerializedSize () + payload->GetSize ();
+}
+
+} // namespace ns3
diff --git a/helper/tracers/ccnx-aggregate-l3-tracer.h b/helper/tracers/ccnx-aggregate-l3-tracer.h
new file mode 100644
index 0000000..8536258
--- /dev/null
+++ b/helper/tracers/ccnx-aggregate-l3-tracer.h
@@ -0,0 +1,88 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2011 UCLA
+ *
+ * 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:  Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ */
+
+#ifndef CCNX_AGGREGATE_L3_TRACER_H
+#define CCNX_AGGREGATE_L3_TRACER_H
+
+#include "ns3/ccnx-l3-tracer.h"
+
+namespace ns3 {
+
+class CcnxAggregateL3Tracer : public CcnxL3Tracer
+{
+public:
+  CcnxAggregateL3Tracer (Ptr<Node> node);
+  CcnxAggregateL3Tracer (const std::string &node);
+  virtual ~CcnxAggregateL3Tracer () { };
+  
+  virtual void
+  PrintHeader (std::ostream &os) const;
+
+  virtual void
+  Print (std::ostream &os) const;
+
+  virtual void
+  OutInterests  (std::string context,
+                 Ptr<const CcnxInterestHeader>, Ptr<const CcnxFace>);
+
+  virtual void
+  InInterests   (std::string context,
+                 Ptr<const CcnxInterestHeader>, Ptr<const CcnxFace>);
+
+  virtual void
+  DropInterests (std::string context,
+                 Ptr<const CcnxInterestHeader>, Ccnx::DropReason, Ptr<const CcnxFace>);
+  
+  virtual void
+  OutNacks  (std::string context,
+             Ptr<const CcnxInterestHeader>, Ptr<const CcnxFace>);
+
+  virtual void
+  InNacks   (std::string context,
+             Ptr<const CcnxInterestHeader>, Ptr<const CcnxFace>);
+
+  virtual void
+  DropNacks (std::string context,
+             Ptr<const CcnxInterestHeader>, Ccnx::DropReason, Ptr<const CcnxFace>);
+  
+  virtual void
+  OutData  (std::string context,
+            Ptr<const CcnxContentObjectHeader>, Ptr<const Packet>, bool fromCache, Ptr<const CcnxFace>);
+
+  virtual void
+  InData   (std::string context,
+            Ptr<const CcnxContentObjectHeader>, Ptr<const Packet>, Ptr<const CcnxFace>);
+
+  virtual void
+  DropData (std::string context,
+            Ptr<const CcnxContentObjectHeader>, Ptr<const Packet>, Ccnx::DropReason, Ptr<const CcnxFace>);
+
+protected:
+  void
+  Reset ();
+  
+protected:
+  Stats m_packets;
+  Stats m_bytes;
+};
+
+} // namespace ns3
+
+#endif // CCNX_AGGREGATE_L3_TRACER_H
diff --git a/helper/tracers/ccnx-app-tracer.cc b/helper/tracers/ccnx-app-tracer.cc
new file mode 100644
index 0000000..a2bbbdd
--- /dev/null
+++ b/helper/tracers/ccnx-app-tracer.cc
@@ -0,0 +1,84 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2011 UCLA
+ *
+ * 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:  Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ */
+
+#include "ccnx-app-tracer.h"
+#include "ns3/node.h"
+#include "ns3/packet.h"
+#include "ns3/config.h"
+#include "ns3/callback.h"
+#include "ns3/names.h"
+
+#include "ns3/ccnx-app.h"
+#include "ns3/ccnx-face.h"
+
+#include <boost/lexical_cast.hpp>
+
+#include "ns3/ccnx-interest-header.h"
+#include "ns3/ccnx-content-object-header.h"
+
+using namespace std;
+using namespace boost;
+
+namespace ns3 {
+    
+CcnxAppTracer::CcnxAppTracer (const std::string &app, Ptr<Node> node, const std::string &appId)
+  : m_app (app)
+  , m_appId (appId)
+  , m_nodePtr (node)
+{
+  m_node = boost::lexical_cast<string> (m_nodePtr->GetId ());
+
+  Connect ();
+
+  string name = Names::FindName (node);
+  if (!name.empty ())
+    {
+      m_node = name;
+    }
+}
+
+CcnxAppTracer::CcnxAppTracer (const std::string &app, const std::string &node, const std::string &appId)
+  : m_app (app)
+  , m_appId (appId)
+  , m_node (node)
+{
+  Connect ();
+}
+
+void
+CcnxAppTracer::Connect ()
+{
+  Config::Connect ("/NodeList/"+m_node+"/ApplicationList/"+m_appId+"/$"+m_app+"/TransmittedInterests",
+                   MakeCallback (&CcnxAppTracer::OutInterests, this));
+
+  Config::Connect ("/NodeList/"+m_node+"/ApplicationList/"+m_appId+"/$"+m_app+"/ReceivedNacks",
+                   MakeCallback (&CcnxAppTracer::InNacks, this));
+
+  Config::Connect ("/NodeList/"+m_node+"/ApplicationList/"+m_appId+"/$"+m_app+"/ReceivedInterests",
+                   MakeCallback (&CcnxAppTracer::InInterests, this));
+  
+  Config::Connect ("/NodeList/"+m_node+"/ApplicationList/"+m_appId+"/$"+m_app+"/TransmittedContentObjects",
+                   MakeCallback (&CcnxAppTracer::OutData, this));
+
+  Config::Connect ("/NodeList/"+m_node+"/ApplicationList/"+m_appId+"/$"+m_app+"/ReceivedContentObjects",
+                   MakeCallback (&CcnxAppTracer::InData, this));
+}
+
+} // namespace ns3
diff --git a/helper/tracers/ccnx-app-tracer.h b/helper/tracers/ccnx-app-tracer.h
new file mode 100644
index 0000000..fd9f42d
--- /dev/null
+++ b/helper/tracers/ccnx-app-tracer.h
@@ -0,0 +1,87 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2011 UCLA
+ *
+ * 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:  Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ */
+
+#ifndef CCNX_APP_TRACER_H
+#define CCNX_APP_TRACER_H
+
+#include "ns3/ptr.h"
+#include "ns3/simple-ref-count.h"
+#include "ns3/ccnx.h"
+
+namespace ns3 {
+
+class CcnxApp;
+
+class CcnxAppTracer : public SimpleRefCount<CcnxAppTracer>
+{
+public:
+  CcnxAppTracer (const std::string &app, Ptr<Node> node, const std::string &appId = "*");
+  CcnxAppTracer (const std::string &app, const std::string &node, const std::string &appId = "*");
+  virtual ~CcnxAppTracer ()  { };
+
+  void
+  Connect ();
+
+  virtual void
+  PrintHeader (std::ostream &os) const = 0;
+  
+  virtual void
+  Print (std::ostream &os) const = 0;
+
+  virtual void
+  OutInterests (std::string context,
+                Ptr<const CcnxInterestHeader>, Ptr<CcnxApp>, Ptr<CcnxFace>) = 0;
+
+  virtual void
+  InInterests  (std::string context,
+                Ptr<const CcnxInterestHeader>, Ptr<CcnxApp>, Ptr<CcnxFace>) = 0;
+
+  virtual void
+  InNacks (std::string context,
+           Ptr<const CcnxInterestHeader>, Ptr<CcnxApp>, Ptr<CcnxFace>) = 0;
+
+  virtual void
+  OutData (std::string context,
+           Ptr<const CcnxContentObjectHeader>, Ptr<const Packet>, Ptr<CcnxApp>, Ptr<CcnxFace>) = 0;
+  
+  virtual void
+  InData  (std::string context,
+           Ptr<const CcnxContentObjectHeader>, Ptr<const Packet>, Ptr<CcnxApp>, Ptr<CcnxFace>) = 0;
+
+protected:
+  std::string m_app;
+  std::string m_appId;
+  std::string m_node;
+  Ptr<Node> m_nodePtr;
+};
+
+inline std::ostream&
+operator << (std::ostream &os, const CcnxAppTracer &tracer)
+{
+  os << "# ";
+  tracer.PrintHeader (os);
+  os << "\n";
+  tracer.Print (os);
+  return os;
+}
+
+} // namespace ns3
+
+#endif // CCNX_APP_TRACER_H
diff --git a/helper/tracers/ccnx-l3-tracer.cc b/helper/tracers/ccnx-l3-tracer.cc
new file mode 100644
index 0000000..415105b
--- /dev/null
+++ b/helper/tracers/ccnx-l3-tracer.cc
@@ -0,0 +1,84 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2011 UCLA
+ *
+ * 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:  Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ */
+
+#include "ccnx-l3-tracer.h"
+#include "ns3/node.h"
+#include "ns3/packet.h"
+#include "ns3/config.h"
+#include "ns3/names.h"
+#include "ns3/callback.h"
+#include "ns3/ccnx-app.h"
+#include "ns3/ccnx-face.h"
+
+#include <boost/lexical_cast.hpp>
+
+#include "ns3/ccnx-interest-header.h"
+#include "ns3/ccnx-content-object-header.h"
+
+using namespace std;
+
+namespace ns3 {
+    
+CcnxL3Tracer::CcnxL3Tracer (Ptr<Node> node)
+: m_nodePtr (node)
+{
+  m_node = boost::lexical_cast<string> (m_nodePtr->GetId ());
+
+  Connect ();
+
+  string name = Names::FindName (node);
+  if (!name.empty ())
+    {
+      m_node = name;
+    }
+}
+
+CcnxL3Tracer::CcnxL3Tracer (const std::string &node)
+: m_node (node)
+{
+  Connect ();
+}
+
+void
+CcnxL3Tracer::Connect ()
+{
+  Config::Connect ("/NodeList/"+m_node+"/$ns3::CcnxL3Protocol/ForwardingStrategy/OutInterests",
+                   MakeCallback (&CcnxL3Tracer::OutInterests, this));
+  Config::Connect ("/NodeList/"+m_node+"/$ns3::CcnxL3Protocol/InInterests",
+                   MakeCallback (&CcnxL3Tracer::InInterests, this));
+  Config::Connect ("/NodeList/"+m_node+"/$ns3::CcnxL3Protocol/DropInterests",
+                   MakeCallback (&CcnxL3Tracer::DropInterests, this));
+
+  Config::Connect ("/NodeList/"+m_node+"/$ns3::CcnxL3Protocol/OutNacks",
+                   MakeCallback (&CcnxL3Tracer::OutNacks, this));
+  Config::Connect ("/NodeList/"+m_node+"/$ns3::CcnxL3Protocol/InNacks",
+                   MakeCallback (&CcnxL3Tracer::InNacks, this));
+  Config::Connect ("/NodeList/"+m_node+"/$ns3::CcnxL3Protocol/DropNacks",
+                   MakeCallback (&CcnxL3Tracer::DropNacks, this));
+
+  Config::Connect ("/NodeList/"+m_node+"/$ns3::CcnxL3Protocol/OutData",
+                   MakeCallback (&CcnxL3Tracer::OutData, this));
+  Config::Connect ("/NodeList/"+m_node+"/$ns3::CcnxL3Protocol/InData",
+                   MakeCallback (&CcnxL3Tracer::InData, this));
+  Config::Connect ("/NodeList/"+m_node+"/$ns3::CcnxL3Protocol/DropData",
+                   MakeCallback (&CcnxL3Tracer::DropData, this));
+}
+
+} // namespace ns3
diff --git a/helper/tracers/ccnx-l3-tracer.h b/helper/tracers/ccnx-l3-tracer.h
new file mode 100644
index 0000000..ac21cef
--- /dev/null
+++ b/helper/tracers/ccnx-l3-tracer.h
@@ -0,0 +1,117 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2011 UCLA
+ *
+ * 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:  Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ */
+
+#ifndef CCNX_L3_TRACER_H
+#define CCNX_L3_TRACER_H
+
+#include "ns3/ptr.h"
+#include "ns3/simple-ref-count.h"
+#include "ns3/ccnx.h"
+
+namespace ns3 {
+
+class Node;
+
+class CcnxL3Tracer : public SimpleRefCount<CcnxL3Tracer>
+{
+public:
+  CcnxL3Tracer (Ptr<Node> node);
+  CcnxL3Tracer (const std::string &node);
+  virtual ~CcnxL3Tracer () { };
+
+  void
+  Connect ();
+  
+  virtual void
+  PrintHeader (std::ostream &os) const = 0;
+
+  virtual void
+  Print (std::ostream &os) const = 0;
+  
+  virtual void
+  OutInterests  (std::string context,
+                 Ptr<const CcnxInterestHeader>, Ptr<const CcnxFace>) = 0;
+
+  virtual void
+  InInterests   (std::string context,
+                 Ptr<const CcnxInterestHeader>, Ptr<const CcnxFace>) = 0;
+
+  virtual void
+  DropInterests (std::string context,
+                 Ptr<const CcnxInterestHeader>, Ccnx::DropReason, Ptr<const CcnxFace>) = 0;
+  
+  virtual void
+  OutNacks  (std::string context,
+             Ptr<const CcnxInterestHeader>, Ptr<const CcnxFace>) = 0;
+
+  virtual void
+  InNacks   (std::string context,
+             Ptr<const CcnxInterestHeader>, Ptr<const CcnxFace>) = 0;
+
+  virtual void
+  DropNacks (std::string context,
+             Ptr<const CcnxInterestHeader>, Ccnx::DropReason, Ptr<const CcnxFace>) = 0;
+
+  
+  virtual void
+  OutData  (std::string context,
+            Ptr<const CcnxContentObjectHeader>, Ptr<const Packet>, bool fromCache, Ptr<const CcnxFace>) = 0;
+
+  virtual void
+  InData   (std::string context,
+            Ptr<const CcnxContentObjectHeader>, Ptr<const Packet>, Ptr<const CcnxFace>) = 0;
+
+  virtual void
+  DropData (std::string context,
+            Ptr<const CcnxContentObjectHeader>, Ptr<const Packet>, Ccnx::DropReason, Ptr<const CcnxFace>) = 0;
+
+protected:
+  std::string m_node;
+  Ptr<Node> m_nodePtr;
+
+  struct Stats
+  {
+    void Reset ();
+    
+    uint64_t m_inInterests;
+    uint64_t m_outInterests;
+    uint64_t m_dropInterests;
+    uint64_t m_inNacks;
+    uint64_t m_outNacks;
+    uint64_t m_dropNacks;
+    uint64_t m_inData;
+    uint64_t m_outData;
+    uint64_t m_dropData;
+  };
+};
+
+inline std::ostream&
+operator << (std::ostream &os, const CcnxL3Tracer &tracer)
+{
+  os << "# ";
+  tracer.PrintHeader (os);
+  os << "\n";
+  tracer.Print (os);
+  return os;
+}
+
+} // namespace ns3
+
+#endif // CCNX_L3_TRACER_H
diff --git a/helper/tracers/ccnx-rate-l3-tracer.cc b/helper/tracers/ccnx-rate-l3-tracer.cc
new file mode 100644
index 0000000..d44ce44
--- /dev/null
+++ b/helper/tracers/ccnx-rate-l3-tracer.cc
@@ -0,0 +1,213 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2011 UCLA
+ *
+ * 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:  Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ */
+
+#include "ccnx-rate-l3-tracer.h"
+#include "ns3/node.h"
+#include "ns3/packet.h"
+#include "ns3/config.h"
+#include "ns3/callback.h"
+#include "ns3/simulator.h"
+
+#include "ns3/ccnx-app.h"
+#include "ns3/ccnx-face.h"
+#include "ns3/ccnx-interest-header.h"
+#include "ns3/ccnx-content-object-header.h"
+
+namespace ns3 {
+    
+CcnxRateL3Tracer::CcnxRateL3Tracer (std::ostream &os, Ptr<Node> node)
+  : CcnxL3Tracer (node)
+  , m_os (os)
+{
+  SetAveragingPeriod (Seconds (1.0));
+}
+
+CcnxRateL3Tracer::CcnxRateL3Tracer (std::ostream &os, const std::string &node)
+  : CcnxL3Tracer (node)
+  , m_os (os)
+{
+  SetAveragingPeriod (Seconds (1.0));
+}
+
+CcnxRateL3Tracer::~CcnxRateL3Tracer ()
+{
+  m_printEvent.Cancel ();
+}
+
+void
+CcnxRateL3Tracer::SetAveragingPeriod (const Time &period)
+{
+  m_period = period;
+  m_printEvent.Cancel ();
+  m_printEvent = Simulator::Schedule (m_period, &CcnxRateL3Tracer::PeriodicPrinter, this);
+}
+
+void
+CcnxRateL3Tracer::PeriodicPrinter ()
+{
+  Print (m_os);
+  Reset ();
+  
+  m_printEvent = Simulator::Schedule (m_period, &CcnxRateL3Tracer::PeriodicPrinter, this);
+}
+
+void
+CcnxRateL3Tracer::PrintHeader (std::ostream &os) const
+{
+  os << "Time" << "\t"
+
+     << "Node" << "\t"
+     << "FaceId" << "\t"
+     << "FaceDescr" << "\t"
+
+     << "Type" << "\t"
+     << "Packets" << "\t"
+     << "Kilobytes";
+}
+
+void
+CcnxRateL3Tracer::Reset ()
+{
+  for (std::map<Ptr<const CcnxFace>, boost::tuple<Stats, Stats, Stats, Stats> >::iterator stats = m_stats.begin ();
+       stats != m_stats.end ();
+       stats++)
+    {
+      stats->second.get<0> ().Reset ();
+      stats->second.get<1> ().Reset ();
+    }
+}
+
+const double alpha = 0.8;
+
+#define STATS(INDEX) stats->second.get<INDEX> ()
+#define RATE(INDEX, fieldName) STATS(INDEX).fieldName / m_period.ToDouble (Time::S)
+
+#define PRINTER(printName, fieldName) \
+STATS(2).fieldName = /*new value*/alpha * RATE(0, fieldName) + /*old value*/(1-alpha) * STATS(2).fieldName; \
+ STATS(3).fieldName = /*new value*/alpha * RATE(1, fieldName) / 1024.0 + /*old value*/(1-alpha) * STATS(3).fieldName; \
+                                                                        \
+os << time.ToDouble (Time::S) << "\t"                                   \
+ << m_node << "\t"                                                      \
+ << stats->first->GetId () << "\t"                                      \
+ << *stats->first << "\t"                                               \
+ << printName << "\t"                                                   \
+ << STATS(2).fieldName  << "\t"                                        \
+ << STATS(3).fieldName << "\n";
+
+void
+CcnxRateL3Tracer::Print (std::ostream &os) const
+{
+  for (std::map<Ptr<const CcnxFace>, boost::tuple<Stats, Stats, Stats, Stats> >::iterator stats = m_stats.begin ();
+       stats != m_stats.end ();
+       stats++)
+    {
+      Time time = Simulator::Now ();
+
+      PRINTER ("InInterests",   m_inInterests);
+      PRINTER ("OutInterests",  m_outInterests);
+      PRINTER ("DropInterests", m_dropInterests);
+      
+      PRINTER ("InNacks",   m_inNacks);
+      PRINTER ("OutNacks",  m_outNacks);
+      PRINTER ("DropNacks", m_dropNacks);
+
+      PRINTER ("InData",   m_inData);
+      PRINTER ("OutData",  m_outData);
+      PRINTER ("DropData", m_dropData);
+    }
+}
+
+
+void
+CcnxRateL3Tracer::OutInterests  (std::string context,
+                                      Ptr<const CcnxInterestHeader> header, Ptr<const CcnxFace> face)
+{
+  m_stats[face].get<0> ().m_outInterests ++;
+  m_stats[face].get<1> ().m_outInterests += header->GetSerializedSize ();
+}
+
+void
+CcnxRateL3Tracer::InInterests   (std::string context,
+                                 Ptr<const CcnxInterestHeader> header, Ptr<const CcnxFace> face)
+{
+  m_stats[face].get<0> ().m_inInterests ++;
+  m_stats[face].get<1> ().m_inInterests += header->GetSerializedSize ();
+}
+
+void
+CcnxRateL3Tracer::DropInterests (std::string context,
+                                      Ptr<const CcnxInterestHeader> header, Ccnx::DropReason, Ptr<const CcnxFace> face)
+{
+  m_stats[face].get<0> ().m_dropInterests ++;
+  m_stats[face].get<1> ().m_dropInterests += header->GetSerializedSize ();
+}
+
+void
+CcnxRateL3Tracer::OutNacks  (std::string context,
+                                  Ptr<const CcnxInterestHeader> header, Ptr<const CcnxFace> face)
+{
+  m_stats[face].get<0> ().m_outNacks ++;
+  m_stats[face].get<1> ().m_outNacks += header->GetSerializedSize ();
+}
+
+void
+CcnxRateL3Tracer::InNacks   (std::string context,
+                                  Ptr<const CcnxInterestHeader> header, Ptr<const CcnxFace> face)
+{
+  m_stats[face].get<0> ().m_inNacks ++;
+  m_stats[face].get<1> ().m_inNacks += header->GetSerializedSize ();
+}
+
+void
+CcnxRateL3Tracer::DropNacks (std::string context,
+                             Ptr<const CcnxInterestHeader> header, Ccnx::DropReason, Ptr<const CcnxFace> face)
+{
+  m_stats[face].get<0> ().m_dropNacks ++;
+  m_stats[face].get<1> ().m_dropNacks += header->GetSerializedSize ();
+}
+
+void
+CcnxRateL3Tracer::OutData  (std::string context,
+                            Ptr<const CcnxContentObjectHeader> header, Ptr<const Packet> payload,
+                            bool fromCache, Ptr<const CcnxFace> face)
+{
+  m_stats[face].get<0> ().m_inData ++;
+  m_stats[face].get<1> ().m_inData += header->GetSerializedSize () + payload->GetSize ();
+}
+
+void
+CcnxRateL3Tracer::InData   (std::string context,
+                            Ptr<const CcnxContentObjectHeader> header, Ptr<const Packet> payload,
+                            Ptr<const CcnxFace> face)
+{
+  m_stats[face].get<0> ().m_outData ++;
+  m_stats[face].get<1> ().m_outData += header->GetSerializedSize () + payload->GetSize ();
+}
+
+void
+CcnxRateL3Tracer::DropData (std::string context,
+                            Ptr<const CcnxContentObjectHeader> header, Ptr<const Packet> payload,
+                            Ccnx::DropReason, Ptr<const CcnxFace> face)
+{
+  m_stats[face].get<0> ().m_dropData ++;
+  m_stats[face].get<1> ().m_dropData += header->GetSerializedSize () + payload->GetSize ();
+}
+
+} // namespace ns3
diff --git a/helper/tracers/ccnx-rate-l3-tracer.h b/helper/tracers/ccnx-rate-l3-tracer.h
new file mode 100644
index 0000000..83e48c4
--- /dev/null
+++ b/helper/tracers/ccnx-rate-l3-tracer.h
@@ -0,0 +1,110 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2011 UCLA
+ *
+ * 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:  Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ */
+
+#ifndef CCNX_RATE_L3_TRACER_H
+#define CCNX_RATE_L3_TRACER_H
+
+#include "ns3/ccnx-l3-tracer.h"
+
+#include "ns3/nstime.h"
+#include "ns3/event-id.h"
+
+#include <boost/tuple/tuple.hpp>
+#include <map>
+
+namespace ns3 {
+
+/**
+ * @ingroup ccnx
+ * @brief CCNx network-layer rate tracer
+ */
+class CcnxRateL3Tracer : public CcnxL3Tracer
+{
+public:
+  /**
+   * @brief Network layer tracer constructor
+   */
+  CcnxRateL3Tracer (std::ostream &os, Ptr<Node> node);
+  CcnxRateL3Tracer (std::ostream &os, const std::string &node);
+  virtual ~CcnxRateL3Tracer ();
+
+  void
+  SetAveragingPeriod (const Time &period);
+  
+  virtual void
+  PrintHeader (std::ostream &os) const;
+
+  virtual void
+  Print (std::ostream &os) const;
+
+  virtual void
+  OutInterests  (std::string context,
+                 Ptr<const CcnxInterestHeader>, Ptr<const CcnxFace>);
+
+  virtual void
+  InInterests   (std::string context,
+                 Ptr<const CcnxInterestHeader>, Ptr<const CcnxFace>);
+
+  virtual void
+  DropInterests (std::string context,
+                 Ptr<const CcnxInterestHeader>, Ccnx::DropReason, Ptr<const CcnxFace>);
+  
+  virtual void
+  OutNacks  (std::string context,
+             Ptr<const CcnxInterestHeader>, Ptr<const CcnxFace>);
+
+  virtual void
+  InNacks   (std::string context,
+             Ptr<const CcnxInterestHeader>, Ptr<const CcnxFace>);
+
+  virtual void
+  DropNacks (std::string context,
+             Ptr<const CcnxInterestHeader>, Ccnx::DropReason, Ptr<const CcnxFace>);
+  
+  virtual void
+  OutData  (std::string context,
+            Ptr<const CcnxContentObjectHeader>, Ptr<const Packet>, bool fromCache, Ptr<const CcnxFace>);
+
+  virtual void
+  InData   (std::string context,
+            Ptr<const CcnxContentObjectHeader>, Ptr<const Packet>, Ptr<const CcnxFace>);
+
+  virtual void
+  DropData (std::string context,
+            Ptr<const CcnxContentObjectHeader>, Ptr<const Packet>, Ccnx::DropReason, Ptr<const CcnxFace>);
+
+private:
+  void
+  PeriodicPrinter ();
+  
+  void
+  Reset ();
+
+private:
+  std::ostream& m_os;
+  Time m_period;
+  EventId m_printEvent;
+
+  mutable std::map<Ptr<const CcnxFace>, boost::tuple<Stats, Stats, Stats, Stats> > m_stats;
+};
+
+} // namespace ns3
+
+#endif // CCNX_RATE_L3_TRACER_H