diff --git a/model/content-store/ccnx-content-store-impl.h b/model/content-store/ccnx-content-store-impl.h
index 9bdc58e..b3275da 100644
--- a/model/content-store/ccnx-content-store-impl.h
+++ b/model/content-store/ccnx-content-store-impl.h
@@ -41,7 +41,7 @@
   Lookup (Ptr<const CcnxInterestHeader> interest);
             
   virtual inline bool
-  Add (Ptr<CcnxContentObjectHeader> header, Ptr<const Packet> packet);
+  Add (Ptr<const CcnxContentObjectHeader> header, Ptr<const Packet> packet);
 
   // virtual bool
   // Remove (Ptr<CcnxInterestHeader> header);
@@ -79,7 +79,7 @@
     
 template<class Container>
 bool 
-CcnxContentStoreImpl<Container>::Add (Ptr<CcnxContentObjectHeader> header, Ptr<const Packet> packet)
+CcnxContentStoreImpl<Container>::Add (Ptr<const CcnxContentObjectHeader> header, Ptr<const Packet> packet)
 {
   // NS_LOG_FUNCTION (this << header->GetName ());
 
diff --git a/model/content-store/ccnx-content-store.cc b/model/content-store/ccnx-content-store.cc
index ccbf200..abbf9c3 100644
--- a/model/content-store/ccnx-content-store.cc
+++ b/model/content-store/ccnx-content-store.cc
@@ -58,7 +58,7 @@
 
 //////////////////////////////////////////////////////////////////////
 
-CcnxContentStoreEntry::CcnxContentStoreEntry (Ptr<CcnxContentObjectHeader> header, Ptr<const Packet> packet)
+CcnxContentStoreEntry::CcnxContentStoreEntry (Ptr<const CcnxContentObjectHeader> header, Ptr<const Packet> packet)
   : m_header (header)
   , m_packet (packet->Copy ())
 {
diff --git a/model/content-store/ccnx-content-store.h b/model/content-store/ccnx-content-store.h
index 34d209d..f0abd61 100644
--- a/model/content-store/ccnx-content-store.h
+++ b/model/content-store/ccnx-content-store.h
@@ -59,7 +59,7 @@
    * The constructor will make a copy of the supplied packet and calls
    * RemoveHeader and RemoveTail on the copy.
    */
-  CcnxContentStoreEntry (Ptr<CcnxContentObjectHeader> header, Ptr<const Packet> packet);
+  CcnxContentStoreEntry (Ptr<const CcnxContentObjectHeader> header, Ptr<const Packet> packet);
 
   /**
    * \brief Get prefix of the stored entry
@@ -90,7 +90,7 @@
   GetFullyFormedCcnxPacket () const;
 
 private:
-  Ptr<CcnxContentObjectHeader> m_header; ///< \brief non-modifiable CcnxContentObjectHeader
+  Ptr<const CcnxContentObjectHeader> m_header; ///< \brief non-modifiable CcnxContentObjectHeader
   Ptr<Packet> m_packet; ///< \brief non-modifiable content of the ContentObject packet
 };
 
@@ -138,7 +138,7 @@
    * @returns true if an existing entry was updated, false otherwise
    */
   virtual bool
-  Add (Ptr<CcnxContentObjectHeader> header, Ptr<const Packet> packet) = 0;
+  Add (Ptr<const CcnxContentObjectHeader> header, Ptr<const Packet> packet) = 0;
 
   // /**
   //  * \brief Add a new content to the content store.
diff --git a/model/forwarding-strategy/ccnx-bestroute-strategy.cc b/model/forwarding-strategy/best-route.cc
similarity index 77%
rename from model/forwarding-strategy/ccnx-bestroute-strategy.cc
rename to model/forwarding-strategy/best-route.cc
index 75efdd4..33d9cde 100644
--- a/model/forwarding-strategy/ccnx-bestroute-strategy.cc
+++ b/model/forwarding-strategy/best-route.cc
@@ -19,7 +19,7 @@
  *         Ilya Moiseenko <iliamo@cs.ucla.edu>
  */
 
-#include "ccnx-bestroute-strategy.h"
+#include "best-route.h"
 
 #include "ns3/ccnx-interest-header.h"
 #include "ns3/ccnx-pit.h"
@@ -33,41 +33,41 @@
 #include <boost/lambda/bind.hpp>
 namespace ll = boost::lambda;
 
-NS_LOG_COMPONENT_DEFINE ("CcnxBestRouteStrategy");
+NS_LOG_COMPONENT_DEFINE ("NdnSimBestRoute");
 
-namespace ns3 
-{
+namespace ns3 {
+namespace ndnSIM {
 
 using namespace __ccnx_private;
 
-NS_OBJECT_ENSURE_REGISTERED (CcnxBestRouteStrategy);
+NS_OBJECT_ENSURE_REGISTERED (BestRoute);
   
-TypeId CcnxBestRouteStrategy::GetTypeId (void)
+TypeId
+BestRoute::GetTypeId (void)
 {
-  static TypeId tid = TypeId ("ns3::CcnxBestRouteStrategy")
+  static TypeId tid = TypeId ("ns3::ndnSIM::BestRoute")
     .SetGroupName ("Ccnx")
-    .SetParent <CcnxForwardingStrategy> ()
-    .AddConstructor <CcnxBestRouteStrategy> ()
+    .SetParent <GreenYellowRed> ()
+    .AddConstructor <BestRoute> ()
     ;
   return tid;
 }
     
-CcnxBestRouteStrategy::CcnxBestRouteStrategy ()
+BestRoute::BestRoute ()
 {
 }
     
 bool
-CcnxBestRouteStrategy::PropagateInterest (Ptr<CcnxPitEntry> pitEntry, 
-                                          const Ptr<CcnxFace> &incomingFace,
-                                          Ptr<CcnxInterestHeader> &header,
-                                          const Ptr<const Packet> &packet)
+BestRoute::DoPropagateInterest (const Ptr<CcnxFace> &incomingFace,
+                                Ptr<CcnxInterestHeader> &header,
+                                const Ptr<const Packet> &packet,
+                                Ptr<CcnxPitEntry> pitEntry)
 {
   NS_LOG_FUNCTION (this);
 
-  
 
   // Try to work out with just green faces
-  bool greenOk = PropagateInterestViaGreen (pitEntry, incomingFace, header, packet);
+  bool greenOk = super::DoPropagateInterest (incomingFace, header, packet, pitEntry);
   if (greenOk)
     return true;
 
@@ -115,5 +115,6 @@
   NS_LOG_INFO ("Propagated to " << propagatedCount << " faces");
   return propagatedCount > 0;
 }
-    
-} //namespace ns3
+
+} // namespace ndnSIM
+} // namespace ns3
diff --git a/model/forwarding-strategy/best-route.h b/model/forwarding-strategy/best-route.h
new file mode 100644
index 0000000..aec1147
--- /dev/null
+++ b/model/forwarding-strategy/best-route.h
@@ -0,0 +1,61 @@
+/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2011 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>
+ *         Ilya Moiseenko <iliamo@cs.ucla.edu>
+ */
+
+
+#ifndef NDNSIM_BEST_ROUTE_H
+#define NDNSIM_BEST_ROUTE_H
+
+#include "green-yellow-red.h"
+
+namespace ns3 {
+namespace ndnSIM {
+
+/**
+ * \ingroup ccnx
+ * \brief Best route strategy
+ */
+class BestRoute :
+    public GreenYellowRed
+{
+public:
+  static TypeId
+  GetTypeId (void);
+
+  /**
+   * @brief Default constructor
+   */
+  BestRoute ();
+        
+  // inherited from  CcnxForwardingStrategy
+  virtual bool
+  DoPropagateInterest (const Ptr<CcnxFace> &incomingFace,
+                       Ptr<CcnxInterestHeader> &header,
+                       const Ptr<const Packet> &packet,
+                       Ptr<CcnxPitEntry> pitEntry);
+
+private:
+  typedef GreenYellowRed super;
+};
+
+} // namespace ndnSIM
+} // namespace ns3
+
+#endif // NDNSIM_BEST_ROUTE_H
diff --git a/model/forwarding-strategy/ccnx-bestroute-strategy.h b/model/forwarding-strategy/ccnx-bestroute-strategy.h
deleted file mode 100644
index 6768da6..0000000
--- a/model/forwarding-strategy/ccnx-bestroute-strategy.h
+++ /dev/null
@@ -1,59 +0,0 @@
-/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
-/*
- * Copyright (c) 2011 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: Ilya Moiseenko <iliamo@cs.ucla.edu>
- */
-
-
-#ifndef CCNX_BESTROUTE_STRATEGY_H
-#define CCNX_BESTROUTE_STRATEGY_H
-
-#include "ccnx-forwarding-strategy.h"
-
-namespace ns3 
-{
-    
-class CcnxFace;
-class CcnxInterestHeader;
-    
-/**
- * \ingroup ccnx
- * \brief Best route strategy
- *
- * \todo Describe
- */
-class CcnxBestRouteStrategy : public CcnxForwardingStrategy
-{
-public:
-  static TypeId GetTypeId (void);
-
-  /**
-   * @brief Default constructor
-   */
-  CcnxBestRouteStrategy ();
-        
-  // inherited from  CcnxForwardingStrategy
-  virtual bool
-  PropagateInterest (Ptr<CcnxPitEntry> pitEntry, 
-                     const Ptr<CcnxFace> &incomingFace,
-                     Ptr<CcnxInterestHeader> &header,
-                     const Ptr<const Packet> &packet);
-};
-
-} //namespace ns3
-
-#endif /* CCNX_BESTROUTE_STRATEGY_H */
diff --git a/model/forwarding-strategy/ccnx-forwarding-strategy.cc b/model/forwarding-strategy/ccnx-forwarding-strategy.cc
index 9cdfa4d..3d6f3de 100644
--- a/model/forwarding-strategy/ccnx-forwarding-strategy.cc
+++ b/model/forwarding-strategy/ccnx-forwarding-strategy.cc
@@ -67,26 +67,20 @@
     ////////////////////////////////////////////////////////////////////
     ////////////////////////////////////////////////////////////////////
 
-    .AddTraceSource ("OutNacks",  "OutNacks",  MakeTraceSourceAccessor (&CcnxForwardingStrategy::m_outNacks))
-    .AddTraceSource ("InNacks",   "InNacks",   MakeTraceSourceAccessor (&CcnxForwardingStrategy::m_inNacks))
-    .AddTraceSource ("DropNacks", "DropNacks", MakeTraceSourceAccessor (&CcnxForwardingStrategy::m_dropNacks))
-    
-    ////////////////////////////////////////////////////////////////////
-    ////////////////////////////////////////////////////////////////////
-
     .AddTraceSource ("OutData",  "OutData",  MakeTraceSourceAccessor (&CcnxForwardingStrategy::m_outData))
     .AddTraceSource ("InData",   "InData",   MakeTraceSourceAccessor (&CcnxForwardingStrategy::m_inData))
     .AddTraceSource ("DropData", "DropData", MakeTraceSourceAccessor (&CcnxForwardingStrategy::m_dropData))
 
-    .AddAttribute ("EnableNACKs", "Enabling support of NACKs",
-                   BooleanValue (false),
-                   MakeBooleanAccessor (&CcnxForwardingStrategy::m_nacksEnabled),
-                   MakeBooleanChecker ())
     .AddAttribute ("CacheUnsolicitedData", "Cache overheard data that have not been requested",
                    BooleanValue (false),
                    MakeBooleanAccessor (&CcnxForwardingStrategy::m_cacheUnsolicitedData),
                    MakeBooleanChecker ())
 
+    .AddAttribute ("DetectRetransmissions", "If non-duplicate interest is received on the same face more than once, "
+                                            "it is considered a retransmission",
+                   BooleanValue (true),
+                   MakeBooleanAccessor (&CcnxForwardingStrategy::m_detectRetransmissions),
+                   MakeBooleanChecker ())
     ;
   return tid;
 }
@@ -139,16 +133,17 @@
   if (pitEntry == 0)
     {
       pitEntry = m_pit->Create (header);
+      if (pitEntry != 0)
+        {
+          DidCreatePitEntry (incomingFace, header, packet, pitEntry);
+        }
+      else
+        {
+          FailedToCreatePitEntry (incomingFace, header, packet);
+          return;
+        }
     }
 
-  if (pitEntry == 0)
-    {
-      // if it is still not created, then give up processing
-      m_dropInterests (header, incomingFace);
-      return;
-    }
-  
-  bool isNew = pitEntry->GetIncoming ().size () == 0 && pitEntry->GetOutgoing ().size () == 0;
   bool isDuplicated = true;
   if (!pitEntry->IsNonceSeen (header->GetNonce ()))
     {
@@ -156,61 +151,9 @@
       isDuplicated = false;
     }
 
-  NS_LOG_FUNCTION (header->GetName () << header->GetNonce () << boost::cref (*incomingFace) << isDuplicated);
-
-  /////////////////////////////////////////////////////////////////////////////////////////
-  /////////////////////////////////////////////////////////////////////////////////////////
-  /////////////////////////////////////////////////////////////////////////////////////////
-  //                                                                                     //
-  // !!!! IMPORTANT CHANGE !!!! Duplicate interests will create incoming face entry !!!! //
-  //                                                                                     //
-  /////////////////////////////////////////////////////////////////////////////////////////
-  /////////////////////////////////////////////////////////////////////////////////////////
-  /////////////////////////////////////////////////////////////////////////////////////////
-  
-  // Data is not in cache
-  CcnxPitEntry::in_iterator inFace   = pitEntry->GetIncoming ().find (incomingFace);
-  CcnxPitEntry::out_iterator outFace = pitEntry->GetOutgoing ().find (incomingFace);
-
-  bool isRetransmitted = false;
-  
-  if (inFace != pitEntry->GetIncoming ().end ())
-    {
-      // CcnxPitEntryIncomingFace.m_arrivalTime keeps track arrival time of the first packet... why?
-
-      isRetransmitted = true;
-      // this is almost definitely a retransmission. But should we trust the user on that?
-    }
-  else
-    {
-      inFace = pitEntry->AddIncoming (incomingFace);
-    }
-  //////////////////////////////////////////////////////////////////////////////////
-  //////////////////////////////////////////////////////////////////////////////////
-  //////////////////////////////////////////////////////////////////////////////////
-  
   if (isDuplicated) 
     {
-      NS_LOG_DEBUG ("Received duplicatie interest on " << *incomingFace);
-      m_dropInterests (header, incomingFace);
-
-      /**
-       * This condition will handle "routing" loops and also recently satisfied interests.
-       * Every time interest is satisfied, PIT entry (with empty incoming and outgoing faces)
-       * is kept for another small chunk of time.
-       */
-
-      if (m_nacksEnabled)
-        {
-          NS_LOG_DEBUG ("Sending NACK_LOOP");
-          header->SetNack (CcnxInterestHeader::NACK_LOOP);
-          Ptr<Packet> nack = Create<Packet> ();
-          nack->AddHeader (*header);
-
-          incomingFace->Send (nack);
-          m_outNacks (header, incomingFace);
-        }
-      
+      DidReceiveDuplicateInterest (incomingFace, header, packet, pitEntry);
       return;
     }
 
@@ -221,64 +164,25 @@
   if (contentObject != 0)
     {
       NS_ASSERT (contentObjectHeader != 0);      
-      NS_LOG_LOGIC("Found in cache");
 
-      OnDataDelayed (contentObjectHeader, payload, contentObject);
+      pitEntry->AddIncoming (incomingFace/*, Seconds (1.0)*/);
+      SatisfyPendingInterest (0, contentObjectHeader, payload, contentObject, pitEntry);
       return;
     }
 
-  // update PIT entry lifetime
-  pitEntry->UpdateLifetime (header->GetInterestLifetime ());
-  
-  if (outFace != pitEntry->GetOutgoing ().end ())
+  if (ShouldSuppressIncomingInterest (incomingFace, pitEntry))
     {
-      NS_LOG_DEBUG ("Non duplicate interests from the face we have sent interest to. Don't suppress");
-      // got a non-duplicate interest from the face we have sent interest to
-      // Probably, there is no point in waiting data from that face... Not sure yet
+      pitEntry->AddIncoming (incomingFace/*, header->GetInterestLifetime ()*/);
+      // update PIT entry lifetime
+      pitEntry->UpdateLifetime (header->GetInterestLifetime ());
 
-      // If we're expecting data from the interface we got the interest from ("producer" asks us for "his own" data)
-      // Mark interface YELLOW, but keep a small hope that data will come eventually.
-
-      // ?? not sure if we need to do that ?? ...
-      
-      pitEntry->GetFibEntry ()->UpdateStatus (incomingFace, CcnxFibFaceMetric::NDN_FIB_YELLOW);
-      // StaticCast<CcnxFibImpl> (m_fib)->modify(pitEntry->GetFibEntry (),
-      //                                          ll::bind (&CcnxFibEntry::UpdateStatus,
-      //                                                    ll::_1, incomingFace, CcnxFibFaceMetric::NDN_FIB_YELLOW));
-    }
-  else
-    if (!isNew && !isRetransmitted)
-      {
-        // Suppress this interest if we're still expecting data from some other face
-        NS_LOG_DEBUG ("Suppress interests");
-        m_dropInterests (header, incomingFace);
-        return;
-      }
-  
-  /////////////////////////////////////////////////////////////////////
-  // Propagate
-  /////////////////////////////////////////////////////////////////////
-  
-  bool propagated = PropagateInterest (pitEntry, incomingFace, header, packet);
-
-  if (!propagated && isRetransmitted) //give another chance if retransmitted
-    {
-      // increase max number of allowed retransmissions
-      pitEntry->IncreaseAllowedRetxCount ();
-
-      // try again
-      propagated = PropagateInterest (pitEntry, incomingFace, header, packet);
-    }
-  
-  // ForwardingStrategy will try its best to forward packet to at least one interface.
-  // If no interests was propagated, then there is not other option for forwarding or
-  // ForwardingStrategy failed to find it. 
-  if (!propagated)
-    {
-      NS_LOG_DEBUG ("Not propagated");
+      // Suppress this interest if we're still expecting data from some other face
+      NS_LOG_DEBUG ("Suppress interests");
       m_dropInterests (header, incomingFace);
-      GiveUpInterest (pitEntry, header);
+      return;
     }
+
+  PropagateInterest (incomingFace, header, packet, pitEntry);
 }
 
 void
@@ -290,205 +194,220 @@
   NS_LOG_FUNCTION (incomingFace << header->GetName () << payload << packet);
   m_inData (header, payload, incomingFace);
   
-  // 1. Lookup PIT entry
+  // Lookup PIT entry
   Ptr<CcnxPitEntry> pitEntry = m_pit->Lookup (*header);
-  if (pitEntry != 0)
+  if (pitEntry == 0)
     {
-      // Note that with MultiIndex we need to modify entries indirectly
-
-      CcnxPitEntry::out_iterator out = pitEntry->GetOutgoing ().find (incomingFace);
-  
-      // If we have sent interest for this data via this face, then update stats.
-      if (out != pitEntry->GetOutgoing ().end ())
-        {
-          pitEntry->GetFibEntry ()->UpdateFaceRtt (incomingFace, Simulator::Now () - out->m_sendTime);
-          // StaticCast<CcnxFibImpl> (m_fib)->modify (pitEntry->GetFibEntry (),
-          //                                          ll::bind (&CcnxFibEntry::UpdateFaceRtt,
-          //                                                    ll::_1,
-          //                                                    incomingFace,
-          //                                                    Simulator::Now () - out->m_sendTime));
-        }
-      else
-        {
-          // Unsolicited data, but we're interested in it... should we get it?
-          // Potential hole for attacks
-
-          if (m_cacheUnsolicitedData)
-            {
-              // Optimistically add or update entry in the content store
-              m_contentStore->Add (header, payload);
-            }
-          else
-            {
-              NS_LOG_ERROR ("PIT entry for "<< header->GetName ()<<" is valid, "
-                            "but outgoing entry for interface "<< boost::cref(*incomingFace) <<" doesn't exist\n");
-            }
-          // ignore unsolicited data
-          return;
-        }
-
-      // Update metric status for the incoming interface in the corresponding FIB entry
-      pitEntry->GetFibEntry ()->UpdateStatus (incomingFace, CcnxFibFaceMetric::NDN_FIB_GREEN);
-      // StaticCast<CcnxFibImpl>(m_fib)->modify (pitEntry->GetFibEntry (),
-      //                                          ll::bind (&CcnxFibEntry::UpdateStatus, ll::_1,
-      //                                                    incomingFace, CcnxFibFaceMetric::NDN_FIB_GREEN));
-  
+      DidReceiveUnsolicitedData (incomingFace, header, payload);
+      return;
+    }
+  else
+    {
       // Add or update entry in the content store
       m_contentStore->Add (header, payload);
-
-      pitEntry->RemoveIncoming (incomingFace);
-
-      if (pitEntry->GetIncoming ().size () == 0)
-        {
-          // Set pruning timout on PIT entry (instead of deleting the record)
-          m_pit->MarkErased (pitEntry);
-        }
-      else
-        {
-          OnDataDelayed (header, payload, packet);
-        }
     }
-  else
+
+  while (pitEntry != 0)
     {
-      NS_LOG_DEBUG ("Pit entry not found");
-      if (m_cacheUnsolicitedData)
-        {
-          // Optimistically add or update entry in the content store
-          m_contentStore->Add (header, payload);
-        }
-      else
-        {
-          // Drop data packet if PIT entry is not found
-          // (unsolicited data packets should not "poison" content store)
-      
-          //drop dulicated or not requested data packet
-          m_dropData (header, payload, incomingFace);
-        }
-      return; // do not process unsoliced data packets
+      // Do data plane performance measurements
+      WillSatisfyPendingInterest (incomingFace, pitEntry);
+
+      // Actually satisfy pending interest
+      SatisfyPendingInterest (incomingFace, header, payload, packet, pitEntry);
+
+      // Lookup another PIT entry
+      pitEntry = m_pit->Lookup (*header);
     }
 }
 
 
+void
+CcnxForwardingStrategy::DidReceiveDuplicateInterest (const Ptr<CcnxFace> &incomingFace,
+                                                     Ptr<CcnxInterestHeader> &header,
+                                                     const Ptr<const Packet> &packet,
+                                                     Ptr<CcnxPitEntry> pitEntry)
+{
+  NS_LOG_FUNCTION (this << *incomingFace);
+  /////////////////////////////////////////////////////////////////////////////////////////
+  //                                                                                     //
+  // !!!! IMPORTANT CHANGE !!!! Duplicate interests will create incoming face entry !!!! //
+  //                                                                                     //
+  /////////////////////////////////////////////////////////////////////////////////////////
+  pitEntry->AddIncoming (incomingFace);
+  m_dropInterests (header, incomingFace);
+}
+
+void
+CcnxForwardingStrategy::DidExhaustForwardingOptions (const Ptr<CcnxFace> &incomingFace,
+                                                     Ptr<CcnxInterestHeader> header,
+                                                     const Ptr<const Packet> &packet,
+                                                     Ptr<CcnxPitEntry> pitEntry)
+{
+  NS_LOG_FUNCTION (this << *incomingFace);
+  m_dropInterests (header, incomingFace);
+}
+
+void
+CcnxForwardingStrategy::FailedToCreatePitEntry (const Ptr<CcnxFace> &incomingFace,
+                                                Ptr<CcnxInterestHeader> header,
+                                                const Ptr<const Packet> &packet)
+{
+  NS_LOG_FUNCTION (this);
+  m_dropInterests (header, incomingFace);
+}
+  
+void
+CcnxForwardingStrategy::DidCreatePitEntry (const Ptr<CcnxFace> &incomingFace,
+                                           Ptr<CcnxInterestHeader> header,
+                                           const Ptr<const Packet> &packet,
+                                           Ptr<CcnxPitEntry> pitEntrypitEntry)
+{
+}
+
 bool
-CcnxForwardingStrategy::PropagateInterestViaGreen (Ptr<CcnxPitEntry> pitEntry, 
-                                                   const Ptr<CcnxFace> &incomingFace,
-                                                   Ptr<CcnxInterestHeader> &header,
-                                                   const Ptr<const Packet> &packet)
+CcnxForwardingStrategy::DetectRetransmittedInterest (const Ptr<CcnxFace> &incomingFace,
+                                                     Ptr<CcnxPitEntry> pitEntry)
 {
-  NS_LOG_FUNCTION (this);
-  NS_ASSERT_MSG (m_pit != 0, "PIT should be aggregated with forwarding strategy");
+  CcnxPitEntry::in_iterator inFace = pitEntry->GetIncoming ().find (incomingFace);
 
-  int propagatedCount = 0;
+  bool isRetransmitted = false;
   
-  BOOST_FOREACH (const CcnxFibFaceMetric &metricFace, pitEntry->GetFibEntry ()->m_faces.get<i_metric> ())
+  if (inFace != pitEntry->GetIncoming ().end ())
     {
-      if (metricFace.m_status == CcnxFibFaceMetric::NDN_FIB_RED ||
-          metricFace.m_status == CcnxFibFaceMetric::NDN_FIB_YELLOW)
-        break; //propagate only to green faces
-
-      if (pitEntry->GetIncoming ().find (metricFace.m_face) != pitEntry->GetIncoming ().end ()) 
-        continue; // don't forward to face that we received interest from
-
-      CcnxPitEntryOutgoingFaceContainer::type::iterator outgoing =
-        pitEntry->GetOutgoing ().find (metricFace.m_face);
-      
-      if (outgoing != pitEntry->GetOutgoing ().end () &&
-          outgoing->m_retxCount >= pitEntry->GetMaxRetxCount ())
-        {
-          NS_LOG_DEBUG ("retxCount: " << outgoing->m_retxCount << ", maxRetxCount: " << pitEntry->GetMaxRetxCount ());
-          continue;
-        }
-      
-      bool faceAvailable = metricFace.m_face->IsBelowLimit ();
-      if (!faceAvailable) // huh...
-        {
-          // let's try different green face
-          continue;
-        }
-
-      pitEntry->AddOutgoing (metricFace.m_face);
-
-      Ptr<Packet> packetToSend = packet->Copy ();
-
-      //transmission
-      metricFace.m_face->Send (packetToSend);
-      m_outInterests (header, metricFace.m_face);
-      
-      propagatedCount++;
-      break; // propagate only one interest
+      // this is almost definitely a retransmission. But should we trust the user on that?
+      isRetransmitted = true;
     }
 
-  return propagatedCount > 0;
+  return isRetransmitted;
 }
 
 void
-CcnxForwardingStrategy::OnDataDelayed (Ptr<const CcnxContentObjectHeader> header,
-                                       Ptr<const Packet> payload,
-                                       const Ptr<const Packet> &packet)
+CcnxForwardingStrategy::SatisfyPendingInterest (const Ptr<CcnxFace> &incomingFace,
+                                                Ptr<const CcnxContentObjectHeader> header,
+                                                Ptr<const Packet> payload,
+                                                const Ptr<const Packet> &packet,
+                                                Ptr<CcnxPitEntry> pitEntry)
 {
-  // 1. Lookup PIT entry
-  Ptr<CcnxPitEntry> pitEntry = m_pit->Lookup (*header);
-  if (pitEntry != 0)
+  if (incomingFace != 0)
+    pitEntry->RemoveIncoming (incomingFace);
+
+  //satisfy all pending incoming Interests
+  BOOST_FOREACH (const CcnxPitEntryIncomingFace &incoming, pitEntry->GetIncoming ())
     {
-      //satisfy all pending incoming Interests
-      BOOST_FOREACH (const CcnxPitEntryIncomingFace &incoming, pitEntry->GetIncoming ())
-        {
-          incoming.m_face->Send (packet->Copy ());
-          m_outData (header, payload, false, incoming.m_face);
-          NS_LOG_DEBUG ("Satisfy " << *incoming.m_face);
+      incoming.m_face->Send (packet->Copy ());
+      m_outData (header, payload, false, incoming.m_face);
+      NS_LOG_DEBUG ("Satisfy " << *incoming.m_face);
           
-          // successfull forwarded data trace
-        }
+      // successfull forwarded data trace
+    }
 
-      if (pitEntry->GetIncoming ().size () > 0)
-        {
-          // All incoming interests are satisfied. Remove them
-          pitEntry->ClearIncoming ();
+  // All incoming interests are satisfied. Remove them
+  pitEntry->ClearIncoming ();
 
-          // Remove all outgoing faces
-          pitEntry->ClearOutgoing ();
+  // Remove all outgoing faces
+  pitEntry->ClearOutgoing ();
           
-          // Set pruning timout on PIT entry (instead of deleting the record)
-          m_pit->MarkErased (pitEntry);
-        }
+  // Set pruning timout on PIT entry (instead of deleting the record)
+  m_pit->MarkErased (pitEntry);
+}
+
+void
+CcnxForwardingStrategy::DidReceiveUnsolicitedData (const Ptr<CcnxFace> &incomingFace,
+                                                   Ptr<const CcnxContentObjectHeader> header,
+                                                   Ptr<const Packet> payload)
+{
+  if (m_cacheUnsolicitedData)
+    {
+      // Optimistically add or update entry in the content store
+      m_contentStore->Add (header, payload);
     }
   else
     {
-      NS_LOG_DEBUG ("Pit entry not found (was satisfied and removed before)");
-      return; // do not process unsoliced data packets
+      // Drop data packet if PIT entry is not found
+      // (unsolicited data packets should not "poison" content store)
+      
+      //drop dulicated or not requested data packet
+      m_dropData (header, payload, incomingFace);
     }
 }
 
 void
-CcnxForwardingStrategy::GiveUpInterest (Ptr<CcnxPitEntry> pitEntry,
-                                        Ptr<CcnxInterestHeader> header)
+CcnxForwardingStrategy::WillSatisfyPendingInterest (const Ptr<CcnxFace> &incomingFace,
+                                                    Ptr<CcnxPitEntry> pitEntry)
 {
-  NS_LOG_FUNCTION (this);
-
-  if (m_nacksEnabled)
+  CcnxPitEntry::out_iterator out = pitEntry->GetOutgoing ().find (incomingFace);
+  
+  // If we have sent interest for this data via this face, then update stats.
+  if (out != pitEntry->GetOutgoing ().end ())
     {
-      Ptr<Packet> packet = Create<Packet> ();
-      header->SetNack (CcnxInterestHeader::NACK_GIVEUP_PIT);
-      packet->AddHeader (*header);
-
-      BOOST_FOREACH (const CcnxPitEntryIncomingFace &incoming, pitEntry->GetIncoming ())
-        {
-          NS_LOG_DEBUG ("Send NACK for " << boost::cref (header->GetName ()) << " to " << boost::cref (*incoming.m_face));
-          incoming.m_face->Send (packet->Copy ());
-
-          m_outNacks (header, incoming.m_face);
-        }
-  
-      // All incoming interests cannot be satisfied. Remove them
-      pitEntry->ClearIncoming ();
-
-      // Remove also outgoing
-      pitEntry->ClearOutgoing ();
-  
-      // Set pruning timout on PIT entry (instead of deleting the record)
-      m_pit->MarkErased (pitEntry);
-    }
+      pitEntry->GetFibEntry ()->UpdateFaceRtt (incomingFace, Simulator::Now () - out->m_sendTime);
+    } 
 }
 
+bool
+CcnxForwardingStrategy::ShouldSuppressIncomingInterest (const Ptr<CcnxFace> &incomingFace,
+                                                        Ptr<CcnxPitEntry> pitEntry)
+{
+  bool isNew = pitEntry->GetIncoming ().size () == 0 && pitEntry->GetOutgoing ().size () == 0;
+
+  if (isNew) return false; // never suppress new interests
+  
+  bool isRetransmitted = m_detectRetransmissions && // a small guard
+                         DetectRetransmittedInterest (incomingFace, pitEntry);  
+
+  if (pitEntry->GetOutgoing ().find (incomingFace) != pitEntry->GetOutgoing ().end ())
+    {
+      NS_LOG_DEBUG ("Non duplicate interests from the face we have sent interest to. Don't suppress");
+      // got a non-duplicate interest from the face we have sent interest to
+      // Probably, there is no point in waiting data from that face... Not sure yet
+
+      // If we're expecting data from the interface we got the interest from ("producer" asks us for "his own" data)
+      // Mark interface YELLOW, but keep a small hope that data will come eventually.
+
+      // ?? not sure if we need to do that ?? ...
+      
+      // pitEntry->GetFibEntry ()->UpdateStatus (incomingFace, CcnxFibFaceMetric::NDN_FIB_YELLOW);
+    }
+  else
+    if (!isNew && !isRetransmitted)
+      {
+        return true;
+      }
+
+  return false;
+}
+
+void
+CcnxForwardingStrategy::PropagateInterest (const Ptr<CcnxFace> &incomingFace,
+                                           Ptr<CcnxInterestHeader> &header,
+                                           const Ptr<const Packet> &packet,
+                                           Ptr<CcnxPitEntry> pitEntry)
+{
+  bool isRetransmitted = m_detectRetransmissions && // a small guard
+                         DetectRetransmittedInterest (incomingFace, pitEntry);  
+  
+  pitEntry->AddIncoming (incomingFace/*, header->GetInterestLifetime ()*/);
+  /// @todo Make lifetime per incoming interface
+  pitEntry->UpdateLifetime (header->GetInterestLifetime ());
+  
+  bool propagated = DoPropagateInterest (incomingFace, header, packet, pitEntry);
+
+  if (!propagated && isRetransmitted) //give another chance if retransmitted
+    {
+      // increase max number of allowed retransmissions
+      pitEntry->IncreaseAllowedRetxCount ();
+
+      // try again
+      propagated = DoPropagateInterest (incomingFace, header, packet, pitEntry);
+    }
+
+  // ForwardingStrategy will try its best to forward packet to at least one interface.
+  // If no interests was propagated, then there is not other option for forwarding or
+  // ForwardingStrategy failed to find it. 
+  if (!propagated && pitEntry->GetOutgoing ().size () == 0)
+    {
+      DidExhaustForwardingOptions (incomingFace, header, packet, pitEntry);
+    }
+}
 
 } //namespace ns3
diff --git a/model/forwarding-strategy/ccnx-forwarding-strategy.h b/model/forwarding-strategy/ccnx-forwarding-strategy.h
index 20d92a4..0683079 100644
--- a/model/forwarding-strategy/ccnx-forwarding-strategy.h
+++ b/model/forwarding-strategy/ccnx-forwarding-strategy.h
@@ -41,7 +41,8 @@
  * \ingroup ccnx
  * \brief Abstract base class for CCNx forwarding strategies
  */
-class CcnxForwardingStrategy : public Object
+class CcnxForwardingStrategy :
+    public Object
 {
 public:
   static TypeId GetTypeId (void);
@@ -80,7 +81,64 @@
           Ptr<Packet> &payload,
           const Ptr<const Packet> &packet);
     
-// protected:
+protected:
+  // events
+  virtual void
+  DidReceiveDuplicateInterest (const Ptr<CcnxFace> &face,
+                               Ptr<CcnxInterestHeader> &header,
+                               const Ptr<const Packet> &packet,
+                               Ptr<CcnxPitEntry> pitEntry);
+
+  virtual void
+  DidExhaustForwardingOptions (const Ptr<CcnxFace> &incomingFace,
+                               Ptr<CcnxInterestHeader> header,
+                               const Ptr<const Packet> &packet,
+                               Ptr<CcnxPitEntry> pitEntry);
+
+  virtual void
+  FailedToCreatePitEntry (const Ptr<CcnxFace> &incomingFace,
+                          Ptr<CcnxInterestHeader> header,
+                          const Ptr<const Packet> &packet);
+  
+  virtual void
+  DidCreatePitEntry (const Ptr<CcnxFace> &incomingFace,
+                     Ptr<CcnxInterestHeader> header,
+                     const Ptr<const Packet> &packet,
+                     Ptr<CcnxPitEntry> pitEntry);
+
+  virtual bool
+  DetectRetransmittedInterest (const Ptr<CcnxFace> &incomingFace,
+                               Ptr<CcnxPitEntry> pitEntry);
+
+  // only for data received from network
+  virtual void
+  WillSatisfyPendingInterest (const Ptr<CcnxFace> &incomingFace,
+                              Ptr<CcnxPitEntry> pitEntry);
+
+  // for data received both from network and cache
+  virtual void
+  SatisfyPendingInterest (const Ptr<CcnxFace> &incomingFace, // 0 allowed (from cache)
+                          Ptr<const CcnxContentObjectHeader> header,
+                          Ptr<const Packet> payload,
+                          const Ptr<const Packet> &packet,
+                          Ptr<CcnxPitEntry> pitEntry);
+
+  virtual void
+  DidReceiveUnsolicitedData (const Ptr<CcnxFace> &incomingFace,
+                             Ptr<const CcnxContentObjectHeader> header,
+                             Ptr<const Packet> payload);
+  
+  virtual bool
+  ShouldSuppressIncomingInterest (const Ptr<CcnxFace> &incomingFace,
+                                  Ptr<CcnxPitEntry> pitEntry);
+
+
+  virtual void
+  PropagateInterest (const Ptr<CcnxFace> &incomingFace,
+                     Ptr<CcnxInterestHeader> &header,
+                     const Ptr<const Packet> &packet,
+                     Ptr<CcnxPitEntry> pitEntry);
+  
   /**
    * @brief Base method to propagate the interest according to the forwarding strategy
    *
@@ -93,38 +151,16 @@
    * @return true if interest was successfully propagated, false if all options have failed
    */
   virtual bool
-  PropagateInterest (Ptr<CcnxPitEntry> pitEntry, 
-                     const Ptr<CcnxFace> &incomingFace,
-                     Ptr<CcnxInterestHeader> &header,
-                     const Ptr<const Packet> &packet) = 0;
+  DoPropagateInterest (const Ptr<CcnxFace> &incomingFace,
+                       Ptr<CcnxInterestHeader> &header,
+                       const Ptr<const Packet> &packet,
+                       Ptr<CcnxPitEntry> pitEntry) = 0;
 
-protected:
-  /**
-   * @brief Propagate interest via a green interface. Fail, if no green interfaces available
-   *
-   * @param pitEntry      Reference to PIT entry (reference to corresponding FIB entry inside)
-   * @param incomingFace  Incoming face
-   * @param header        CcnxInterestHeader
-   * @param packet        Original Interest packet
-   * @param sendCallback  Send callback
-   * @return true if interest was successfully propagated, false if all options have failed
-   *
-   * \see PropagateInterest
-   */
-  bool
-  PropagateInterestViaGreen (Ptr<CcnxPitEntry> pitEntry, 
-                             const Ptr<CcnxFace> &incomingFace,
-                             Ptr<CcnxInterestHeader> &header,
-                             const Ptr<const Packet> &packet);
 
-  virtual void
-  GiveUpInterest (Ptr<CcnxPitEntry> pitEntry,
-                  Ptr<CcnxInterestHeader> header);
-
-  virtual void
-  OnDataDelayed (Ptr<const CcnxContentObjectHeader> header,
-                 Ptr<const Packet> payload,
-                 const Ptr<const Packet> &packet);
+  // virtual void
+  // OnDataDelayed (Ptr<const CcnxContentObjectHeader> header,
+  //                Ptr<const Packet> payload,
+  //                const Ptr<const Packet> &packet);
   
 protected:
   // inherited from Object class                                                                                                                                                        
@@ -136,11 +172,8 @@
   Ptr<CcnxFib> m_fib; ///< \brief FIB  
   Ptr<CcnxContentStore> m_contentStore; ///< \brief Content store (for caching purposes only)
 
-  bool m_nacksEnabled;
   bool m_cacheUnsolicitedData;
-
-  // transmittedInterestTrace is inside ForwardingStrategy
-  
+  bool m_detectRetransmissions;
   
   TracedCallback<Ptr<const CcnxInterestHeader>,
                  Ptr<const CcnxFace> > m_outInterests; ///< @brief Transmitted interests trace
@@ -155,19 +188,6 @@
   ////////////////////////////////////////////////////////////////////
   ////////////////////////////////////////////////////////////////////
 
-  TracedCallback<Ptr<const CcnxInterestHeader>,
-                 Ptr<const CcnxFace> > m_outNacks; ///< @brief trace of outgoing NACKs
-
-  TracedCallback<Ptr<const CcnxInterestHeader>,
-                 Ptr<const CcnxFace> > m_inNacks; ///< @brief trace of incoming NACKs
-
-  TracedCallback<Ptr<const CcnxInterestHeader>,
-                 Ptr<const CcnxFace> > m_dropNacks; ///< @brief trace of dropped NACKs
-
-  ////////////////////////////////////////////////////////////////////
-  ////////////////////////////////////////////////////////////////////
-  ////////////////////////////////////////////////////////////////////
-
   TracedCallback<Ptr<const CcnxContentObjectHeader>, Ptr<const Packet>,
                  bool /*from cache*/,
                  Ptr<const CcnxFace> > m_outData; ///< @brief trace of outgoing Data
diff --git a/model/forwarding-strategy/ccnx-flooding-strategy.cc b/model/forwarding-strategy/flooding.cc
similarity index 69%
rename from model/forwarding-strategy/ccnx-flooding-strategy.cc
rename to model/forwarding-strategy/flooding.cc
index c803560..79a29b9 100644
--- a/model/forwarding-strategy/ccnx-flooding-strategy.cc
+++ b/model/forwarding-strategy/flooding.cc
@@ -19,7 +19,7 @@
  *         Ilya Moiseenko <iliamo@cs.ucla.edu>
  */
 
-#include "ccnx-flooding-strategy.h"
+#include "flooding.h"
 
 #include "ns3/ccnx-interest-header.h"
 #include "ns3/ccnx-pit.h"
@@ -36,53 +36,37 @@
 #include <boost/lambda/bind.hpp>
 namespace ll = boost::lambda;
 
-NS_LOG_COMPONENT_DEFINE ("CcnxFloodingStrategy");
+NS_LOG_COMPONENT_DEFINE ("NdnSimFlooding");
 
-namespace ns3 
-{
+namespace ns3 {
+namespace ndnSIM {
 
 using namespace __ccnx_private;
 
-NS_OBJECT_ENSURE_REGISTERED (CcnxFloodingStrategy);
+NS_OBJECT_ENSURE_REGISTERED (Flooding);
     
-TypeId CcnxFloodingStrategy::GetTypeId (void)
+TypeId Flooding::GetTypeId (void)
 {
-  static TypeId tid = TypeId ("ns3::CcnxFloodingStrategy")
+  static TypeId tid = TypeId ("ns3::ndnSIM::Flooding")
     .SetGroupName ("Ccnx")
-    .SetParent <CcnxForwardingStrategy> ()
-    .AddConstructor <CcnxFloodingStrategy> ()
-
-    .AddAttribute ("SmartFlooding",
-                   "If true then if a GREEN face exists, Interests will be sent only to such face (!only to one green face!)",
-                   BooleanValue (false),
-                   MakeBooleanAccessor (&CcnxFloodingStrategy::m_smartFlooding),
-                   MakeBooleanChecker ())
+    .SetParent <Nacks> ()
+    .AddConstructor <Flooding> ()
     ;
   return tid;
 }
     
-CcnxFloodingStrategy::CcnxFloodingStrategy ()
+Flooding::Flooding ()
 {
 }
 
 bool
-CcnxFloodingStrategy::PropagateInterest (Ptr<CcnxPitEntry> pitEntry, 
-                                         const Ptr<CcnxFace> &incomingFace,
-                                         Ptr<CcnxInterestHeader> &header,
-                                         const Ptr<const Packet> &packet)
+Flooding::DoPropagateInterest (const Ptr<CcnxFace> &incomingFace,
+                               Ptr<CcnxInterestHeader> &header,
+                               const Ptr<const Packet> &packet,
+                               Ptr<CcnxPitEntry> pitEntry)
 {
   NS_LOG_FUNCTION (this);
 
-  if (m_smartFlooding)
-    {
-      // Try to work out with just green faces
-      bool greenOk = PropagateInterestViaGreen (pitEntry, incomingFace, header, packet);
-      if (greenOk)
-        return true;
-      
-      // boo... :(
-    }
-
   int propagatedCount = 0;
 
   BOOST_FOREACH (const CcnxFibFaceMetric &metricFace, pitEntry->GetFibEntry ()->m_faces.get<i_metric> ())
@@ -128,5 +112,6 @@
   NS_LOG_INFO ("Propagated to " << propagatedCount << " faces");
   return propagatedCount > 0;
 }
-    
-} //namespace ns3
+
+} // namespace ndnSIM
+} // namespace ns3
diff --git a/model/forwarding-strategy/ccnx-flooding-strategy.h b/model/forwarding-strategy/flooding.h
similarity index 60%
rename from model/forwarding-strategy/ccnx-flooding-strategy.h
rename to model/forwarding-strategy/flooding.h
index fa77988..99a6b9c 100644
--- a/model/forwarding-strategy/ccnx-flooding-strategy.h
+++ b/model/forwarding-strategy/flooding.h
@@ -15,27 +15,26 @@
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  *
- * Author: Ilya Moiseenko <iliamo@cs.ucla.edu>
+ * Author: Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ *         Ilya Moiseenko <iliamo@cs.ucla.edu>
  */
 
-#ifndef CCNX_FLOODING_STRATEGY_H
-#define CCNX_FLOODING_STRATEGY_H
+#ifndef NDNSIM_FLOODING_H
+#define NDNSIM_FLOODING_H
 
-#include "ccnx-forwarding-strategy.h"
+#include "nacks.h"
 
-namespace ns3 
-{
-    
-class CcnxFace;
-class CcnxInterestHeader;
-    
+namespace ns3 {
+namespace ndnSIM {
+
 /**
  * \ingroup ccnx
  * \brief Flooding strategy
  *
  * \todo Describe
  */
-class CcnxFloodingStrategy : public CcnxForwardingStrategy
+class Flooding :
+    public Nacks
 {
 public:
   static TypeId GetTypeId (void);
@@ -43,19 +42,21 @@
   /**
    * @brief Default constructor
    */
-  CcnxFloodingStrategy ();
+  Flooding ();
 
-  // inherited from  CcnxForwardingStrategy
+protected:
+  // inherited from  Nacks/CcnxForwardingStrategy
   virtual bool
-  PropagateInterest (Ptr<CcnxPitEntry> pitEntry, 
-                     const Ptr<CcnxFace> &incomingFace,
-                     Ptr<CcnxInterestHeader> &header,
-                     const Ptr<const Packet> &packet);
+  DoPropagateInterest (const Ptr<CcnxFace> &incomingFace,
+                       Ptr<CcnxInterestHeader> &header,
+                       const Ptr<const Packet> &packet,
+                       Ptr<CcnxPitEntry> pitEntry);
 
 private:
-  bool m_smartFlooding;
+  typedef Nacks super;
 };
-    
-} //namespace ns3
 
-#endif /* CCNX_FLOODING_STRATEGY_H */
+} // namespace ndnSIM
+} // namespace ns3
+
+#endif // NDNSIM_FLOODING
diff --git a/model/forwarding-strategy/green-yellow-red.cc b/model/forwarding-strategy/green-yellow-red.cc
new file mode 100644
index 0000000..f945bbe
--- /dev/null
+++ b/model/forwarding-strategy/green-yellow-red.cc
@@ -0,0 +1,130 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2011 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>
+ *          Ilya Moiseenko <iliamo@cs.ucla.edu>
+ */
+
+#include "green-yellow-red.h"
+
+#include "ns3/ccnx-pit.h"
+#include "ns3/ccnx-pit-entry.h"
+#include "ns3/ccnx-interest-header.h"
+#include "ns3/ccnx-content-object-header.h"
+#include "ns3/ccnx-pit.h"
+#include "ns3/ccnx-fib.h"
+#include "ns3/ccnx-content-store.h"
+
+#include "ns3/assert.h"
+#include "ns3/ptr.h"
+#include "ns3/log.h"
+#include "ns3/simulator.h"
+#include "ns3/boolean.h"
+#include "ns3/string.h"
+
+#include <boost/ref.hpp>
+#include <boost/foreach.hpp>
+#include <boost/lambda/lambda.hpp>
+#include <boost/lambda/bind.hpp>
+#include <boost/tuple/tuple.hpp>
+namespace ll = boost::lambda;
+
+NS_LOG_COMPONENT_DEFINE ("NdnSimGreenYellowRed");
+
+namespace ns3 {
+
+using namespace __ccnx_private;
+
+namespace ndnSIM {
+
+NS_OBJECT_ENSURE_REGISTERED (GreenYellowRed);
+
+TypeId
+GreenYellowRed::GetTypeId (void)
+{
+  static TypeId tid = TypeId ("ns3::ndnSIM::GreenYellowRed")
+    .SetGroupName ("Ccnx")
+    .SetParent<CcnxForwardingStrategy> ()
+
+    ;
+  return tid;
+}
+
+bool
+GreenYellowRed::DoPropagateInterest (const Ptr<CcnxFace> &incomingFace,
+                                     Ptr<CcnxInterestHeader> &header,
+                                     const Ptr<const Packet> &packet,
+                                     Ptr<CcnxPitEntry> pitEntry)
+{
+  NS_LOG_FUNCTION (this);
+  NS_ASSERT_MSG (m_pit != 0, "PIT should be aggregated with forwarding strategy");
+
+  int propagatedCount = 0;
+  
+  BOOST_FOREACH (const CcnxFibFaceMetric &metricFace, pitEntry->GetFibEntry ()->m_faces.get<i_metric> ())
+    {
+      if (metricFace.m_status == CcnxFibFaceMetric::NDN_FIB_RED ||
+          metricFace.m_status == CcnxFibFaceMetric::NDN_FIB_YELLOW)
+        break; //propagate only to green faces
+
+      if (pitEntry->GetIncoming ().find (metricFace.m_face) != pitEntry->GetIncoming ().end ()) 
+        continue; // don't forward to face that we received interest from
+
+      CcnxPitEntryOutgoingFaceContainer::type::iterator outgoing =
+        pitEntry->GetOutgoing ().find (metricFace.m_face);
+      
+      if (outgoing != pitEntry->GetOutgoing ().end () &&
+          outgoing->m_retxCount >= pitEntry->GetMaxRetxCount ())
+        {
+          NS_LOG_DEBUG ("retxCount: " << outgoing->m_retxCount << ", maxRetxCount: " << pitEntry->GetMaxRetxCount ());
+          continue;
+        }
+      
+      bool faceAvailable = metricFace.m_face->IsBelowLimit ();
+      if (!faceAvailable) // huh...
+        {
+          // let's try different green face
+          continue;
+        }
+
+      pitEntry->AddOutgoing (metricFace.m_face);
+
+      Ptr<Packet> packetToSend = packet->Copy ();
+
+      //transmission
+      metricFace.m_face->Send (packetToSend);
+      m_outInterests (header, metricFace.m_face);
+      
+      propagatedCount++;
+      break; // propagate only one interest
+    }
+
+  return propagatedCount > 0;
+}
+
+void
+GreenYellowRed::WillSatisfyPendingInterest (const Ptr<CcnxFace> &incomingFace,
+                                            Ptr<CcnxPitEntry> pitEntry)
+{
+  // Update metric status for the incoming interface in the corresponding FIB entry
+  pitEntry->GetFibEntry ()->UpdateStatus (incomingFace, CcnxFibFaceMetric::NDN_FIB_GREEN);
+
+  super::WillSatisfyPendingInterest (incomingFace, pitEntry);
+}
+
+} // namespace ndnSIM
+} // namespace ns3
diff --git a/model/forwarding-strategy/green-yellow-red.h b/model/forwarding-strategy/green-yellow-red.h
new file mode 100644
index 0000000..71f4955
--- /dev/null
+++ b/model/forwarding-strategy/green-yellow-red.h
@@ -0,0 +1,56 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2011 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>
+ *          Ilya Moiseenko <iliamo@cs.ucla.edu>
+ */
+#ifndef NDNSIM_GREEN_YELLOW_RED_H
+#define NDNSIM_GREEN_YELLOW_RED_H
+
+#include "ccnx-forwarding-strategy.h"
+
+namespace ns3 {
+namespace ndnSIM {
+
+/**
+ * \ingroup ccnx
+ */
+class GreenYellowRed :
+    public CcnxForwardingStrategy
+{
+public:
+  static TypeId GetTypeId (void);
+
+protected:
+  virtual void
+  WillSatisfyPendingInterest (const Ptr<CcnxFace> &incomingFace,
+                              Ptr<CcnxPitEntry> pitEntry);
+
+  virtual bool
+  DoPropagateInterest (const Ptr<CcnxFace> &incomingFace,
+                       Ptr<CcnxInterestHeader> &header,
+                       const Ptr<const Packet> &packet,
+                       Ptr<CcnxPitEntry> pitEntry);
+
+private:
+  typedef CcnxForwardingStrategy super;
+};
+
+} // namespace ndnSIM
+} // namespace ns3
+
+#endif // NDNSIM_GREEN_YELLOW_RED
diff --git a/model/forwarding-strategy/nacks.cc b/model/forwarding-strategy/nacks.cc
new file mode 100644
index 0000000..925788c
--- /dev/null
+++ b/model/forwarding-strategy/nacks.cc
@@ -0,0 +1,148 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2011 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>
+ */
+
+#include "nacks.h"
+
+#include "ns3/ccnx-pit.h"
+#include "ns3/ccnx-pit-entry.h"
+#include "ns3/ccnx-interest-header.h"
+#include "ns3/ccnx-content-object-header.h"
+#include "ns3/ccnx-pit.h"
+#include "ns3/ccnx-fib.h"
+#include "ns3/ccnx-content-store.h"
+
+#include "ns3/assert.h"
+#include "ns3/ptr.h"
+#include "ns3/log.h"
+#include "ns3/simulator.h"
+#include "ns3/boolean.h"
+#include "ns3/string.h"
+
+#include <boost/ref.hpp>
+#include <boost/foreach.hpp>
+#include <boost/lambda/lambda.hpp>
+#include <boost/lambda/bind.hpp>
+#include <boost/tuple/tuple.hpp>
+namespace ll = boost::lambda;
+
+NS_LOG_COMPONENT_DEFINE ("NdnSimNacks");
+
+namespace ns3 {
+namespace ndnSIM {
+
+NS_OBJECT_ENSURE_REGISTERED (Nacks);
+
+TypeId
+Nacks::GetTypeId (void)
+{
+  static TypeId tid = TypeId ("ns3::ndnSIM::Nacks")
+    .SetGroupName ("Ccnx")
+    .SetParent<CcnxForwardingStrategy> ()
+    
+    ////////////////////////////////////////////////////////////////////
+    ////////////////////////////////////////////////////////////////////
+
+    .AddTraceSource ("OutNacks",  "OutNacks",  MakeTraceSourceAccessor (&Nacks::m_outNacks))
+    .AddTraceSource ("InNacks",   "InNacks",   MakeTraceSourceAccessor (&Nacks::m_inNacks))
+    .AddTraceSource ("DropNacks", "DropNacks", MakeTraceSourceAccessor (&Nacks::m_dropNacks))
+    
+    .AddAttribute ("EnableNACKs", "Enabling support of NACKs",
+                   BooleanValue (false),
+                   MakeBooleanAccessor (&Nacks::m_nacksEnabled),
+                   MakeBooleanChecker ())
+    ;
+  return tid;
+}
+
+void
+Nacks::OnInterest (const Ptr<CcnxFace> &incomingFace,
+                   Ptr<CcnxInterestHeader> &header,
+                   const Ptr<const Packet> &packet)
+{
+  if (header->GetNack () > 0)
+    OnNack (incomingFace, header, packet/*original packet*/);
+  else
+    super::OnInterest (incomingFace, header, packet/*original packet*/);  
+}
+
+void
+Nacks::OnNack (const Ptr<CcnxFace> &face,
+               Ptr<CcnxInterestHeader> &header,
+               const Ptr<const Packet> &p)
+{
+  NS_ASSERT (false);
+}
+
+void
+Nacks::DidReceiveDuplicateInterest (const Ptr<CcnxFace> &incomingFace,
+                                    Ptr<CcnxInterestHeader> &header,
+                                    const Ptr<const Packet> &packet,
+                                    Ptr<CcnxPitEntry> pitEntry)
+{
+  super::DidReceiveDuplicateInterest (incomingFace, header, packet, pitEntry);
+
+  if (m_nacksEnabled)
+    {
+      NS_LOG_DEBUG ("Sending NACK_LOOP");
+      header->SetNack (CcnxInterestHeader::NACK_LOOP);
+      Ptr<Packet> nack = Create<Packet> ();
+      nack->AddHeader (*header);
+
+      incomingFace->Send (nack);
+      m_outNacks (header, incomingFace);
+    }
+}
+
+void
+Nacks::DidExhaustForwardingOptions (const Ptr<CcnxFace> &incomingFace,
+                                    Ptr<CcnxInterestHeader> header,
+                                    const Ptr<const Packet> &packet,
+                                    Ptr<CcnxPitEntry> pitEntry)
+{
+  super::DidExhaustForwardingOptions (incomingFace, header, packet, pitEntry);
+
+  if (m_nacksEnabled)
+    {
+      Ptr<Packet> packet = Create<Packet> ();
+      header->SetNack (CcnxInterestHeader::NACK_GIVEUP_PIT);
+      packet->AddHeader (*header);
+
+      BOOST_FOREACH (const CcnxPitEntryIncomingFace &incoming, pitEntry->GetIncoming ())
+        {
+          NS_LOG_DEBUG ("Send NACK for " << boost::cref (header->GetName ()) << " to " << boost::cref (*incoming.m_face));
+          incoming.m_face->Send (packet->Copy ());
+
+          m_outNacks (header, incoming.m_face);
+        }
+  
+      // All incoming interests cannot be satisfied. Remove them
+      pitEntry->ClearIncoming ();
+
+      // Remove also outgoing
+      pitEntry->ClearOutgoing ();
+  
+      // Set pruning timout on PIT entry (instead of deleting the record)
+      m_pit->MarkErased (pitEntry);
+    }  
+}
+
+
+} // namespace ndnSIM
+} // namespace ns3
diff --git a/model/forwarding-strategy/nacks.h b/model/forwarding-strategy/nacks.h
new file mode 100644
index 0000000..fbcec9f
--- /dev/null
+++ b/model/forwarding-strategy/nacks.h
@@ -0,0 +1,97 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2011 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 NDNSIM_NACKS_H
+#define NDNSIM_NACKS_H
+
+#include "ns3/ccnx-forwarding-strategy.h"
+
+namespace ns3 {
+
+namespace ndnSIM {
+
+/**
+ * \ingroup ccnx
+ * \brief Abstract base class for CCNx forwarding strategies
+ */
+class Nacks :
+    public CcnxForwardingStrategy
+{
+public:
+  static TypeId
+  GetTypeId (void);
+
+  /**
+   * \brief Actual processing of incoming CCNx interests. Note, interests do not have payload
+   * 
+   * Processing Interest packets
+   * @param face    incoming face
+   * @param header  deserialized Interest header
+   * @param packet  original packet
+   */
+  virtual void
+  OnInterest (const Ptr<CcnxFace> &face,
+              Ptr<CcnxInterestHeader> &header,
+              const Ptr<const Packet> &p);
+
+protected:
+  // using CcnxForwardingStrategy::PropagateInterest; // some strange c++ cheating
+
+  virtual void
+  DidReceiveDuplicateInterest (const Ptr<CcnxFace> &face,
+                               Ptr<CcnxInterestHeader> &header,
+                               const Ptr<const Packet> &packet,
+                               Ptr<CcnxPitEntry> pitEntry);
+  
+  virtual void
+  DidExhaustForwardingOptions (const Ptr<CcnxFace> &incomingFace,
+                               Ptr<CcnxInterestHeader> header,
+                               const Ptr<const Packet> &packet,
+                               Ptr<CcnxPitEntry> pitEntry);
+
+  virtual void
+  OnNack (const Ptr<CcnxFace> &face,
+          Ptr<CcnxInterestHeader> &header,
+          const Ptr<const Packet> &p);
+
+  // virtual void
+  // OnDataDelayed (Ptr<const CcnxContentObjectHeader> header,
+  //                Ptr<const Packet> payload,
+  //                const Ptr<const Packet> &packet);
+  
+protected:  
+  bool m_nacksEnabled;
+
+  TracedCallback<Ptr<const CcnxInterestHeader>,
+                 Ptr<const CcnxFace> > m_outNacks; ///< @brief trace of outgoing NACKs
+
+  TracedCallback<Ptr<const CcnxInterestHeader>,
+                 Ptr<const CcnxFace> > m_inNacks; ///< @brief trace of incoming NACKs
+
+  TracedCallback<Ptr<const CcnxInterestHeader>,
+                 Ptr<const CcnxFace> > m_dropNacks; ///< @brief trace of dropped NACKs
+
+private:
+  typedef CcnxForwardingStrategy super;
+};
+
+} // namespace ndnSIM
+} // namespace ns3
+
+#endif // NDNSIM_NACKS
diff --git a/model/forwarding-strategy/ccnx-flooding-strategy.cc b/model/forwarding-strategy/smart-flooding.cc
similarity index 68%
copy from model/forwarding-strategy/ccnx-flooding-strategy.cc
copy to model/forwarding-strategy/smart-flooding.cc
index c803560..20bc7ba 100644
--- a/model/forwarding-strategy/ccnx-flooding-strategy.cc
+++ b/model/forwarding-strategy/smart-flooding.cc
@@ -16,10 +16,9 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  *
  * Author: Alexander Afanasyev <alexander.afanasyev@ucla.edu>
- *         Ilya Moiseenko <iliamo@cs.ucla.edu>
  */
 
-#include "ccnx-flooding-strategy.h"
+#include "smart-flooding.h"
 
 #include "ns3/ccnx-interest-header.h"
 #include "ns3/ccnx-pit.h"
@@ -36,52 +35,43 @@
 #include <boost/lambda/bind.hpp>
 namespace ll = boost::lambda;
 
-NS_LOG_COMPONENT_DEFINE ("CcnxFloodingStrategy");
+NS_LOG_COMPONENT_DEFINE ("NdnSimSmartFlooding");
 
-namespace ns3 
-{
+namespace ns3 {
 
 using namespace __ccnx_private;
 
-NS_OBJECT_ENSURE_REGISTERED (CcnxFloodingStrategy);
-    
-TypeId CcnxFloodingStrategy::GetTypeId (void)
-{
-  static TypeId tid = TypeId ("ns3::CcnxFloodingStrategy")
-    .SetGroupName ("Ccnx")
-    .SetParent <CcnxForwardingStrategy> ()
-    .AddConstructor <CcnxFloodingStrategy> ()
+namespace ndnSIM {
 
-    .AddAttribute ("SmartFlooding",
-                   "If true then if a GREEN face exists, Interests will be sent only to such face (!only to one green face!)",
-                   BooleanValue (false),
-                   MakeBooleanAccessor (&CcnxFloodingStrategy::m_smartFlooding),
-                   MakeBooleanChecker ())
+NS_OBJECT_ENSURE_REGISTERED (SmartFlooding);
+    
+TypeId
+SmartFlooding::GetTypeId (void)
+{
+  static TypeId tid = TypeId ("ns3::ndnSIM::SmartFloodingy")
+    .SetGroupName ("Ccnx")
+    .SetParent <GreenYellowRed> ()
+    .AddConstructor <SmartFlooding> ()
     ;
   return tid;
 }
     
-CcnxFloodingStrategy::CcnxFloodingStrategy ()
+SmartFlooding::SmartFlooding ()
 {
 }
 
 bool
-CcnxFloodingStrategy::PropagateInterest (Ptr<CcnxPitEntry> pitEntry, 
-                                         const Ptr<CcnxFace> &incomingFace,
-                                         Ptr<CcnxInterestHeader> &header,
-                                         const Ptr<const Packet> &packet)
+SmartFlooding::DoPropagateInterest (const Ptr<CcnxFace> &incomingFace,
+                                    Ptr<CcnxInterestHeader> &header,
+                                    const Ptr<const Packet> &packet,
+                                    Ptr<CcnxPitEntry> pitEntry)
 {
   NS_LOG_FUNCTION (this);
 
-  if (m_smartFlooding)
-    {
-      // Try to work out with just green faces
-      bool greenOk = PropagateInterestViaGreen (pitEntry, incomingFace, header, packet);
-      if (greenOk)
-        return true;
-      
-      // boo... :(
-    }
+  // Try to work out with just green faces
+  bool greenOk = super::DoPropagateInterest (incomingFace, header, packet, pitEntry);
+  if (greenOk)
+    return true;
 
   int propagatedCount = 0;
 
@@ -128,5 +118,6 @@
   NS_LOG_INFO ("Propagated to " << propagatedCount << " faces");
   return propagatedCount > 0;
 }
-    
-} //namespace ns3
+
+} // namespace ndnSIM
+} // namespace ns3
diff --git a/model/forwarding-strategy/smart-flooding.h b/model/forwarding-strategy/smart-flooding.h
new file mode 100644
index 0000000..3e1cca6
--- /dev/null
+++ b/model/forwarding-strategy/smart-flooding.h
@@ -0,0 +1,57 @@
+/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2011 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 NDNSIM_SMART_FLOODING_H
+#define NDNSIM_SMART_FLOODING_H
+
+#include "green-yellow-red.h"
+
+namespace ns3 {
+namespace ndnSIM {
+
+/**
+ * \ingroup ccnx
+ */
+class SmartFlooding :
+    public GreenYellowRed
+{
+public:
+  static TypeId GetTypeId (void);
+
+  /**
+   * @brief Default constructor
+   */
+  SmartFlooding ();
+
+  // inherited
+  virtual bool
+  DoPropagateInterest (const Ptr<CcnxFace> &incomingFace,
+                       Ptr<CcnxInterestHeader> &header,
+                       const Ptr<const Packet> &packet,
+                       Ptr<CcnxPitEntry> pitEntry);
+
+private:
+  typedef GreenYellowRed super;
+};
+
+} // namespace ndnSIM
+} // namespace ns3
+
+#endif // NDNSIM_SMART_FLOODING_H