diff --git a/utils/tracers/ndn-l3-aggregate-tracer.cc b/utils/tracers/ndn-l3-aggregate-tracer.cc
new file mode 100644
index 0000000..1280ede
--- /dev/null
+++ b/utils/tracers/ndn-l3-aggregate-tracer.cc
@@ -0,0 +1,193 @@
+/* -*- 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 "ndn-l3-aggregate-tracer.h"
+
+#include "ns3/node.h"
+#include "ns3/packet.h"
+#include "ns3/config.h"
+#include "ns3/callback.h"
+#include "ns3/ndn-app.h"
+#include "ns3/ndn-face.h"
+#include "ns3/ndn-interest.h"
+#include "ns3/ndn-content-object.h"
+
+namespace ns3 {
+namespace ndn {
+
+L3AggregateTracer::L3AggregateTracer (Ptr<Node> node)
+: L3Tracer (node)
+{
+  Reset ();
+}
+
+L3AggregateTracer::L3AggregateTracer (const std::string &node)
+: L3Tracer (node)
+{
+  Reset ();
+}
+
+L3AggregateTracer::~L3AggregateTracer ()
+{
+};
+
+void
+L3AggregateTracer::Reset ()
+{
+  m_packets.Reset ();
+  m_bytes.Reset ();
+}
+
+
+void
+L3AggregateTracer::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
+L3AggregateTracer::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
+L3AggregateTracer::OutInterests  (std::string context,
+                                  Ptr<const InterestHeader> header, Ptr<const Face>)
+{
+  m_packets.m_outInterests++;
+  m_bytes.m_outInterests += header->GetSerializedSize ();
+}
+
+void
+L3AggregateTracer::InInterests   (std::string context,
+                                  Ptr<const InterestHeader> header, Ptr<const Face>)
+{
+  m_packets.m_inInterests++;
+  m_bytes.m_inInterests += header->GetSerializedSize ();
+}
+
+void
+L3AggregateTracer::DropInterests (std::string context,
+                                  Ptr<const InterestHeader> header, Ptr<const Face>)
+{
+  m_packets.m_dropInterests++;
+  m_bytes.m_dropInterests += header->GetSerializedSize ();
+}
+
+void
+L3AggregateTracer::OutNacks  (std::string context,
+                              Ptr<const InterestHeader> header, Ptr<const Face>)
+{
+  m_packets.m_outNacks++;
+  m_bytes.m_outNacks += header->GetSerializedSize ();
+}
+
+void
+L3AggregateTracer::InNacks   (std::string context,
+                              Ptr<const InterestHeader> header, Ptr<const Face>)
+{
+  m_packets.m_inNacks++;
+  m_bytes.m_inNacks += header->GetSerializedSize ();
+}
+
+void
+L3AggregateTracer::DropNacks (std::string context,
+                              Ptr<const InterestHeader> header, Ptr<const Face>)
+{
+  m_packets.m_dropNacks++;
+  m_bytes.m_dropNacks += header->GetSerializedSize ();
+}
+
+void
+L3AggregateTracer::OutData  (std::string context,
+                             Ptr<const ContentObjectHeader> header, Ptr<const Packet> payload,
+                             bool fromCache, Ptr<const Face>)
+{
+  m_packets.m_outData++;
+  m_bytes.m_outData += header->GetSerializedSize () + payload->GetSize ();
+}
+
+void
+L3AggregateTracer::InData   (std::string context,
+                             Ptr<const ContentObjectHeader> header, Ptr<const Packet> payload,
+                             Ptr<const Face>)
+{
+  m_packets.m_inData++;
+  m_bytes.m_inData += header->GetSerializedSize () + payload->GetSize ();
+}
+
+void
+L3AggregateTracer::DropData (std::string context,
+                             Ptr<const ContentObjectHeader> header, Ptr<const Packet> payload,
+                             Ptr<const Face>)
+{
+  m_packets.m_dropData++;
+  m_bytes.m_dropData += header->GetSerializedSize () + payload->GetSize ();
+}
+
+} // namespace ndn
+} // namespace ns3
diff --git a/utils/tracers/ndn-l3-aggregate-tracer.h b/utils/tracers/ndn-l3-aggregate-tracer.h
new file mode 100644
index 0000000..bd9cbd0
--- /dev/null
+++ b/utils/tracers/ndn-l3-aggregate-tracer.h
@@ -0,0 +1,99 @@
+/* -*- 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 NDN_L3_AGGREGATE_TRACER_H
+#define NDN_L3_AGGREGATE_TRACER_H
+
+#include "ndn-l3-tracer.h"
+
+#include <ns3/nstime.h>
+#include <ns3/event-id.h>
+
+namespace ns3 {
+namespace ndn {
+
+class L3AggregateTracer : public L3Tracer
+{
+public:
+  L3AggregateTracer (Ptr<Node> node);
+  L3AggregateTracer (const std::string &node);
+  virtual ~L3AggregateTracer ();
+  
+  virtual void
+  PrintHeader (std::ostream &os) const;
+
+  virtual void
+  Print (std::ostream &os) const;
+
+  virtual void
+  OutInterests  (std::string context,
+                 Ptr<const InterestHeader>, Ptr<const Face>);
+
+  virtual void
+  InInterests   (std::string context,
+                 Ptr<const InterestHeader>, Ptr<const Face>);
+
+  virtual void
+  DropInterests (std::string context,
+                 Ptr<const InterestHeader>, Ptr<const Face>);
+  
+  virtual void
+  OutNacks  (std::string context,
+             Ptr<const InterestHeader>, Ptr<const Face>);
+
+  virtual void
+  InNacks   (std::string context,
+             Ptr<const InterestHeader>, Ptr<const Face>);
+
+  virtual void
+  DropNacks (std::string context,
+             Ptr<const InterestHeader>, Ptr<const Face>);
+  
+  virtual void
+  OutData  (std::string context,
+            Ptr<const ContentObjectHeader>, Ptr<const Packet>, bool fromCache, Ptr<const Face>);
+
+  virtual void
+  InData   (std::string context,
+            Ptr<const ContentObjectHeader>, Ptr<const Packet>, Ptr<const Face>);
+
+  virtual void
+  DropData (std::string context,
+            Ptr<const ContentObjectHeader>, Ptr<const Packet>, Ptr<const Face>);
+
+protected:
+  void
+  Reset ();
+
+  void
+  PeriodicPrinter ();
+  
+protected:
+  Stats m_packets;
+  Stats m_bytes;
+
+  Time m_period;
+  EventId m_printEvent;
+};
+
+} // namespace ndn
+} // namespace ns3
+
+#endif // NDN_L3_AGGREGATE_TRACER_H
diff --git a/utils/tracers/ndn-l3-rate-tracer.cc b/utils/tracers/ndn-l3-rate-tracer.cc
new file mode 100644
index 0000000..6604f0b
--- /dev/null
+++ b/utils/tracers/ndn-l3-rate-tracer.cc
@@ -0,0 +1,262 @@
+/* -*- 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 "ndn-l3-rate-tracer.h"
+#include "ns3/node.h"
+#include "ns3/packet.h"
+#include "ns3/config.h"
+#include "ns3/callback.h"
+#include "ns3/simulator.h"
+#include "ns3/log.h"
+#include "ns3/node-list.h"
+
+#include "ns3/ndn-app.h"
+#include "ns3/ndn-face.h"
+#include "ns3/ndn-interest.h"
+#include "ns3/ndn-content-object.h"
+
+#include <fstream>
+#include <boost/lexical_cast.hpp>
+
+using namespace boost;
+using namespace std;
+
+NS_LOG_COMPONENT_DEFINE ("ndn.L3RateTracer");
+
+namespace ns3 {
+namespace ndn {
+
+
+boost::tuple< boost::shared_ptr<std::ostream>, std::list<Ptr<L3RateTracer> > >
+L3RateTracer::InstallAll (const std::string &file, Time averagingPeriod/* = Seconds (0.5)*/)
+{
+  std::list<Ptr<L3RateTracer> > tracers;
+  boost::shared_ptr<std::ofstream> outputStream (new std::ofstream ());
+  outputStream->open (file.c_str (), std::ios_base::out | std::ios_base::trunc);
+
+  if (!outputStream->is_open ())
+    return boost::make_tuple (outputStream, tracers);
+
+  for (NodeList::Iterator node = NodeList::Begin ();
+       node != NodeList::End ();
+       node++)
+    {
+      NS_LOG_DEBUG ("Node: " << lexical_cast<string> ((*node)->GetId ()));
+
+      Ptr<L3RateTracer> trace = Create<L3RateTracer> (outputStream, *node);
+      trace->SetAveragingPeriod (averagingPeriod);
+      tracers.push_back (trace);
+    }
+
+  if (tracers.size () > 0)
+    {
+      // *m_l3RateTrace << "# "; // not necessary for R's read.table
+      tracers.front ()->PrintHeader (*outputStream);
+      *outputStream << "\n";
+    }
+
+  return boost::make_tuple (outputStream, tracers);
+}
+
+
+L3RateTracer::L3RateTracer (boost::shared_ptr<std::ostream> os, Ptr<Node> node)
+  : L3Tracer (node)
+  , m_os (os)
+{
+  SetAveragingPeriod (Seconds (1.0));
+}
+
+L3RateTracer::L3RateTracer (boost::shared_ptr<std::ostream> os, const std::string &node)
+  : L3Tracer (node)
+  , m_os (os)
+{
+  SetAveragingPeriod (Seconds (1.0));
+}
+
+L3RateTracer::~L3RateTracer ()
+{
+  m_printEvent.Cancel ();
+}
+
+void
+L3RateTracer::SetAveragingPeriod (const Time &period)
+{
+  m_period = period;
+  m_printEvent.Cancel ();
+  m_printEvent = Simulator::Schedule (m_period, &L3RateTracer::PeriodicPrinter, this);
+}
+
+void
+L3RateTracer::PeriodicPrinter ()
+{
+  Print (*m_os);
+  Reset ();
+  
+  m_printEvent = Simulator::Schedule (m_period, &L3RateTracer::PeriodicPrinter, this);
+}
+
+void
+L3RateTracer::PrintHeader (std::ostream &os) const
+{
+  os << "Time" << "\t"
+
+     << "Node" << "\t"
+     << "FaceId" << "\t"
+     << "FaceDescr" << "\t"
+
+     << "Type" << "\t"
+     << "Packets" << "\t"
+     << "Kilobytes" << "\t"
+     << "PacketRaw" << "\t"
+     << "KilobytesRaw";
+}
+
+void
+L3RateTracer::Reset ()
+{
+  for (std::map<Ptr<const Face>, 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 << "\t"                                         \
+  << STATS(0).fieldName << "\t"                                         \
+  << STATS(1).fieldName << "\n";
+
+void
+L3RateTracer::Print (std::ostream &os) const
+{
+  for (std::map<Ptr<const Face>, 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
+L3RateTracer::OutInterests  (std::string context,
+                             Ptr<const InterestHeader> header, Ptr<const Face> face)
+{
+  m_stats[face].get<0> ().m_outInterests ++;
+  m_stats[face].get<1> ().m_outInterests += header->GetSerializedSize ();
+}
+
+void
+L3RateTracer::InInterests   (std::string context,
+                             Ptr<const InterestHeader> header, Ptr<const Face> face)
+{
+  m_stats[face].get<0> ().m_inInterests ++;
+  m_stats[face].get<1> ().m_inInterests += header->GetSerializedSize ();
+}
+
+void
+L3RateTracer::DropInterests (std::string context,
+                             Ptr<const InterestHeader> header, Ptr<const Face> face)
+{
+  m_stats[face].get<0> ().m_dropInterests ++;
+  m_stats[face].get<1> ().m_dropInterests += header->GetSerializedSize ();
+}
+
+void
+L3RateTracer::OutNacks  (std::string context,
+                         Ptr<const InterestHeader> header, Ptr<const Face> face)
+{
+  m_stats[face].get<0> ().m_outNacks ++;
+  m_stats[face].get<1> ().m_outNacks += header->GetSerializedSize ();
+}
+
+void
+L3RateTracer::InNacks   (std::string context,
+                         Ptr<const InterestHeader> header, Ptr<const Face> face)
+{
+  m_stats[face].get<0> ().m_inNacks ++;
+  m_stats[face].get<1> ().m_inNacks += header->GetSerializedSize ();
+}
+
+void
+L3RateTracer::DropNacks (std::string context,
+                         Ptr<const InterestHeader> header, Ptr<const Face> face)
+{
+  m_stats[face].get<0> ().m_dropNacks ++;
+  m_stats[face].get<1> ().m_dropNacks += header->GetSerializedSize ();
+}
+
+void
+L3RateTracer::OutData  (std::string context,
+                        Ptr<const ContentObjectHeader> header, Ptr<const Packet> payload,
+                        bool fromCache, Ptr<const Face> face)
+{
+  m_stats[face].get<0> ().m_inData ++;
+  m_stats[face].get<1> ().m_inData += header->GetSerializedSize () + payload->GetSize ();
+}
+
+void
+L3RateTracer::InData   (std::string context,
+                        Ptr<const ContentObjectHeader> header, Ptr<const Packet> payload,
+                        Ptr<const Face> face)
+{
+  m_stats[face].get<0> ().m_outData ++;
+  m_stats[face].get<1> ().m_outData += header->GetSerializedSize () + payload->GetSize ();
+}
+
+void
+L3RateTracer::DropData (std::string context,
+                        Ptr<const ContentObjectHeader> header, Ptr<const Packet> payload,
+                        Ptr<const Face> face)
+{
+  m_stats[face].get<0> ().m_dropData ++;
+  m_stats[face].get<1> ().m_dropData += header->GetSerializedSize () + payload->GetSize ();
+}
+
+} // namespace ndn
+} // namespace ns3
diff --git a/utils/tracers/ndn-l3-rate-tracer.h b/utils/tracers/ndn-l3-rate-tracer.h
new file mode 100644
index 0000000..ced3113
--- /dev/null
+++ b/utils/tracers/ndn-l3-rate-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_RATE_L3_TRACER_H
+#define CCNX_RATE_L3_TRACER_H
+
+#include "ndn-l3-tracer.h"
+
+#include "ns3/nstime.h"
+#include "ns3/event-id.h"
+
+#include <boost/tuple/tuple.hpp>
+#include <boost/shared_ptr.hpp>
+#include <map>
+#include <list>
+
+namespace ns3 {
+namespace ndn {
+
+/**
+ * @ingroup ccnx
+ * @brief CCNx network-layer rate tracer
+ */
+class L3RateTracer : public L3Tracer
+{
+public:
+  /**
+   * @brief Network layer tracer constructor
+   */
+  L3RateTracer (boost::shared_ptr<std::ostream> os, Ptr<Node> node);
+  L3RateTracer (boost::shared_ptr<std::ostream> os, const std::string &node);
+  virtual ~L3RateTracer ();
+
+  static boost::tuple< boost::shared_ptr<std::ostream>, std::list<Ptr<L3RateTracer> > >
+  InstallAll (const std::string &file, Time averagingPeriod = Seconds (0.5));
+  
+  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 InterestHeader>, Ptr<const Face>);
+
+  virtual void
+  InInterests   (std::string context,
+                 Ptr<const InterestHeader>, Ptr<const Face>);
+
+  virtual void
+  DropInterests (std::string context,
+                 Ptr<const InterestHeader>, Ptr<const Face>);
+  
+  virtual void
+  OutNacks  (std::string context,
+             Ptr<const InterestHeader>, Ptr<const Face>);
+
+  virtual void
+  InNacks   (std::string context,
+             Ptr<const InterestHeader>, Ptr<const Face>);
+
+  virtual void
+  DropNacks (std::string context,
+             Ptr<const InterestHeader>, Ptr<const Face>);
+  
+  virtual void
+  OutData  (std::string context,
+            Ptr<const ContentObjectHeader>, Ptr<const Packet>, bool fromCache, Ptr<const Face>);
+
+  virtual void
+  InData   (std::string context,
+            Ptr<const ContentObjectHeader>, Ptr<const Packet>, Ptr<const Face>);
+
+  virtual void
+  DropData (std::string context,
+            Ptr<const ContentObjectHeader>, Ptr<const Packet>, Ptr<const Face>);
+
+private:
+  void
+  PeriodicPrinter ();
+  
+  void
+  Reset ();
+
+private:
+  boost::shared_ptr<std::ostream> m_os;
+  Time m_period;
+  EventId m_printEvent;
+
+  mutable std::map<Ptr<const Face>, boost::tuple<Stats, Stats, Stats, Stats> > m_stats;
+};
+
+} // namespace ndn
+} // namespace ns3
+
+#endif // CCNX_RATE_L3_TRACER_H
diff --git a/utils/tracers/ndn-l3-tracer.cc b/utils/tracers/ndn-l3-tracer.cc
new file mode 100644
index 0000000..847de2a
--- /dev/null
+++ b/utils/tracers/ndn-l3-tracer.cc
@@ -0,0 +1,91 @@
+/* -*- 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 "ndn-l3-tracer.h"
+#include "ns3/node.h"
+#include "ns3/packet.h"
+#include "ns3/config.h"
+#include "ns3/names.h"
+#include "ns3/callback.h"
+
+#include <boost/lexical_cast.hpp>
+
+#include "ns3/ndn-face.h"
+#include "ns3/ndn-interest.h"
+#include "ns3/ndn-content-object.h"
+
+using namespace std;
+
+namespace ns3 {
+namespace ndn {
+    
+L3Tracer::L3Tracer (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;
+    }
+}
+
+L3Tracer::L3Tracer (const std::string &node)
+: m_node (node)
+{
+  Connect ();
+}
+
+L3Tracer::~L3Tracer ()
+{
+};
+
+
+void
+L3Tracer::Connect ()
+{
+  Config::Connect ("/NodeList/"+m_node+"/$ns3::ndn::ForwardingStrategy/OutInterests",
+                   MakeCallback (&L3Tracer::OutInterests, this));
+  Config::Connect ("/NodeList/"+m_node+"/$ns3::ndn::ForwardingStrategy/InInterests",
+                   MakeCallback (&L3Tracer::InInterests, this));
+  Config::Connect ("/NodeList/"+m_node+"/$ns3::ndn::ForwardingStrategy/DropInterests",
+                   MakeCallback (&L3Tracer::DropInterests, this));
+
+  Config::Connect ("/NodeList/"+m_node+"/$ns3::ndn::ForwardingStrategy/OutData",
+                   MakeCallback (&L3Tracer::OutData, this));
+  Config::Connect ("/NodeList/"+m_node+"/$ns3::ndn::ForwardingStrategy/InData",
+                   MakeCallback (&L3Tracer::InData, this));
+  Config::Connect ("/NodeList/"+m_node+"/$ns3::ndn::ForwardingStrategy/DropData",
+                   MakeCallback (&L3Tracer::DropData, this));
+
+  // only for some strategies
+  Config::Connect ("/NodeList/"+m_node+"/$ns3::ndn::ForwardingStrategy/OutNacks",
+                   MakeCallback (&L3Tracer::OutNacks, this));
+  Config::Connect ("/NodeList/"+m_node+"/$ns3::ndn::ForwardingStrategy/InNacks",
+                   MakeCallback (&L3Tracer::InNacks, this));
+  Config::Connect ("/NodeList/"+m_node+"/$ns3::ndn::ForwardingStrategy/DropNacks",
+                   MakeCallback (&L3Tracer::DropNacks, this));
+}
+
+} // namespace ndn
+} // namespace ns3
diff --git a/utils/tracers/ndn-l3-tracer.h b/utils/tracers/ndn-l3-tracer.h
new file mode 100644
index 0000000..74c0ef9
--- /dev/null
+++ b/utils/tracers/ndn-l3-tracer.h
@@ -0,0 +1,135 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2011-2012 University of California, Los Angeles
+ *
+ * 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"
+
+namespace ns3 {
+
+class Node;
+class Packet;
+
+namespace ndn {
+
+class InterestHeader;
+class Face;
+class ContentObjectHeader;
+
+class L3Tracer : public SimpleRefCount<L3Tracer>
+{
+public:
+  L3Tracer (Ptr<Node> node);
+  L3Tracer (const std::string &node);
+  virtual ~L3Tracer ();
+
+  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 InterestHeader>, Ptr<const Face>) = 0;
+
+  virtual void
+  InInterests   (std::string context,
+                 Ptr<const InterestHeader>, Ptr<const Face>) = 0;
+
+  virtual void
+  DropInterests (std::string context,
+                 Ptr<const InterestHeader>, Ptr<const Face>) = 0;
+  
+  virtual void
+  OutNacks  (std::string context,
+             Ptr<const InterestHeader>, Ptr<const Face>) = 0;
+
+  virtual void
+  InNacks   (std::string context,
+             Ptr<const InterestHeader>, Ptr<const Face>) = 0;
+
+  virtual void
+  DropNacks (std::string context,
+             Ptr<const InterestHeader>, Ptr<const Face>) = 0;
+
+  
+  virtual void
+  OutData  (std::string context,
+            Ptr<const ContentObjectHeader>, Ptr<const Packet>, bool fromCache, Ptr<const Face>) = 0;
+
+  virtual void
+  InData   (std::string context,
+            Ptr<const ContentObjectHeader>, Ptr<const Packet>, Ptr<const Face>) = 0;
+
+  virtual void
+  DropData (std::string context,
+            Ptr<const ContentObjectHeader>, Ptr<const Packet>, Ptr<const Face>) = 0;
+
+protected:
+  std::string m_node;
+  Ptr<Node> m_nodePtr;
+
+  struct Stats
+  {
+    inline void 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;
+    }
+    
+    double m_inInterests;
+    double m_outInterests;
+    double m_dropInterests;
+    double m_inNacks;
+    double m_outNacks;
+    double m_dropNacks;
+    double m_inData;
+    double m_outData;
+    double m_dropData;
+  };
+};
+
+inline std::ostream&
+operator << (std::ostream &os, const L3Tracer &tracer)
+{
+  os << "# ";
+  tracer.PrintHeader (os);
+  os << "\n";
+  tracer.Print (os);
+  return os;
+}
+
+} // namespace ndn
+} // namespace ns3
+
+#endif // CCNX_L3_TRACER_H