diff --git a/apps/ccnx-consumer.cc b/apps/ccnx-consumer.cc
index c81e464..9fe2f64 100644
--- a/apps/ccnx-consumer.cc
+++ b/apps/ccnx-consumer.cc
@@ -33,6 +33,7 @@
 #include "../model/ccnx-local-face.h"
 #include "ns3/ccnx-interest-header.h"
 #include "ns3/ccnx-content-object-header.h"
+#include "ns3/ccnx-path-stretch-tag.h"
 
 #include <boost/ref.hpp>
 #include <boost/lexical_cast.hpp>
@@ -91,6 +92,9 @@
 
     .AddTraceSource ("TransmittedInterests", "TransmittedInterests",
                     MakeTraceSourceAccessor (&CcnxConsumer::m_transmittedInterests))
+
+    .AddTraceSource ("PathWeightsTrace", "PathWeightsTrace",
+                    MakeTraceSourceAccessor (&CcnxConsumer::m_pathWeightsTrace))
     ;
 
   return tid;
@@ -129,8 +133,6 @@
 {
   Time now = Simulator::Now ();
 
-  boost::mutex::scoped_lock (m_seqTimeoutsGuard);
-
   Time rto = m_rtt->RetransmitTimeout ();
   
   while (!m_seqTimeouts.empty ())
@@ -181,8 +183,6 @@
 
   NS_LOG_FUNCTION_NOARGS ();
 
-  boost::mutex::scoped_lock (m_seqTimeoutsGuard);
-
   uint32_t seq;
   
   if (m_retxSeqs.size () != 0)
@@ -267,8 +267,6 @@
   uint32_t seq = boost::lexical_cast<uint32_t> (contentObject->GetName ().GetComponents ().back ());
   NS_LOG_INFO ("< DATA for " << seq);
 
-  boost::mutex::scoped_lock (m_seqTimeoutsGuard);
-  
   // SeqTimeoutsContainer::iterator entry = m_seqTimeouts.find (seq);
 
   //  NS_ASSERT_MSG (entry != m_seqTimeouts.end (),
@@ -281,6 +279,14 @@
   m_retxSeqs.erase (seq);
 
   m_rtt->AckSeq (SequenceNumber32 (seq));
+
+  Ptr<const WeightsPathStretchTag> tag = payload->RemovePacketTag<WeightsPathStretchTag> ();
+  if (tag != 0)
+    {
+      // Notify trace about path weights vector (e.g., for path-stretch calculation)
+      m_pathWeightsTrace (GetNode (), tag->GetDestinationNode (), seq, tag->GetTotalWeight ()); 
+      // std::cout << boost::cref(*tag) << "\n";
+    }
 }
 
 void
@@ -291,7 +297,6 @@
   CcnxApp::OnNack (interest, origPacket); // tracing inside
   
   NS_LOG_DEBUG ("Nack type: " << interest->GetNack ());
-  boost::mutex::scoped_lock (m_seqTimeoutsGuard);
 
   NS_LOG_FUNCTION (this << interest);
 
diff --git a/apps/ccnx-consumer.h b/apps/ccnx-consumer.h
index 9f2ae53..0030a81 100644
--- a/apps/ccnx-consumer.h
+++ b/apps/ccnx-consumer.h
@@ -37,8 +37,6 @@
 #include <boost/multi_index/ordered_index.hpp>
 #include <boost/multi_index/member.hpp>
 
-#include <boost/thread/mutex.hpp>
-
 namespace ns3 
 {
 
@@ -169,13 +167,14 @@
     > { } ;
 
   SeqTimeoutsContainer m_seqTimeouts;       ///< \brief multi-index for the set of SeqTimeout structs
-  boost::mutex m_seqTimeoutsGuard;          ///< \brief mutex for safe work with the m_seqTimeouts
 
   /**
    * \brief A trace that is called after each transmitted Interest packet
    */
   TracedCallback<Ptr<const CcnxInterestHeader>,
                  Ptr<CcnxApp>, Ptr<CcnxFace> > m_transmittedInterests;
+  
+  TracedCallback<Ptr<Node>, Ptr<Node>, uint32_t, uint32_t > m_pathWeightsTrace;
 };
 
 } // namespace ns3
diff --git a/apps/ccnx-producer.cc b/apps/ccnx-producer.cc
index cff6af4..291fb82 100644
--- a/apps/ccnx-producer.cc
+++ b/apps/ccnx-producer.cc
@@ -23,6 +23,7 @@
 #include "ns3/log.h"
 #include "ns3/ccnx-interest-header.h"
 #include "ns3/ccnx-content-object-header.h"
+#include "ns3/ccnx-path-stretch-tag.h"
 #include "ns3/string.h"
 #include "ns3/uinteger.h"
 #include "ns3/packet.h"
@@ -113,7 +114,19 @@
   NS_LOG_INFO ("Respodning with ContentObject:\n" << boost::cref(*header));
   
   Ptr<Packet> packet = Create<Packet> (m_virtualPayloadSize);
+  Ptr<const WeightsPathStretchTag> tag = origPacket->RemovePacketTag<WeightsPathStretchTag> ();
+  if (tag != 0)
+    {
+      // std::cout << Simulator::Now () << ", " << m_app->GetInstanceTypeId ().GetName () << "\n";
 
+      // echo back WeightsPathStretchTag
+      packet->AddPacketTag (CreateObject<WeightsPathStretchTag> (*tag));
+
+      // \todo
+      // packet->AddPacketTag should actually accept Ptr<const WeightsPathStretchTag> instead of
+      // Ptr<WeightsPathStretchTag>.  Echoing will be simplified after change is done
+    }
+  
   m_transmittedContentObjects (header, packet, this, m_face);
   
   packet->AddHeader (*header);