diff --git a/model/sync-full-state.cc b/model/sync-full-state.cc
index 801bfbf..b30d2d4 100644
--- a/model/sync-full-state.cc
+++ b/model/sync-full-state.cc
@@ -64,14 +64,18 @@
 {
   if (m_digest == 0)
     {
+      // std::cout << "getDigest: ";
       m_digest = make_shared<Digest> ();
       BOOST_FOREACH (LeafConstPtr leaf, m_leaves.get<ordered> ())
         {
           FullLeafConstPtr fullLeaf = dynamic_pointer_cast<const FullLeaf> (leaf);
           BOOST_ASSERT (fullLeaf != 0);
           *m_digest << fullLeaf->getDigest ();
+          // std::cout << *leaf << "[" << fullLeaf->getDigest () << "] ";
         }
+      // std::cout << "\n";
     }
+  m_digest->finalize ();
 
   return m_digest;
 }
diff --git a/model/sync-leaf.h b/model/sync-leaf.h
index 037e4a5..00ae151 100644
--- a/model/sync-leaf.h
+++ b/model/sync-leaf.h
@@ -72,6 +72,13 @@
 typedef boost::shared_ptr<Leaf> LeafPtr;
 typedef boost::shared_ptr<const Leaf> LeafConstPtr;
 
+inline std::ostream &
+operator << (std::ostream &os, const Leaf &leaf)
+{
+  os << leaf.getInfo () << "(" << leaf.getSeq () << ")";
+  return os;
+}
+
 } // Sync
 
 #endif // SYNC_LEAF_H
diff --git a/model/sync-name-info.cc b/model/sync-name-info.cc
index 8f730e3..270e6fc 100644
--- a/model/sync-name-info.cc
+++ b/model/sync-name-info.cc
@@ -22,18 +22,12 @@
 
 #include "sync-name-info.h"
 
-#include <boost/lexical_cast.hpp>
+// #include <boost/lexical_cast.hpp>
 
 namespace Sync {
 
 NameInfo::NameMap NameInfo::m_names;
 size_t  NameInfo::m_ids = 0;
-
-/**
- * @brief Calculates digest of the name
- */
-// tempalte<>
-// Digest
-// NameInfo::getDigest<PrefixInfo> () const;
+boost::mutex NameInfo::m_namesMutex;
 
 } // Sync
diff --git a/model/sync-name-info.h b/model/sync-name-info.h
index ebe946b..a4d7e7d 100644
--- a/model/sync-name-info.h
+++ b/model/sync-name-info.h
@@ -24,6 +24,8 @@
 #define SYNC_NAME_INFO_H
 
 #include <boost/shared_ptr.hpp>
+#include <boost/weak_ptr.hpp>
+#include <boost/thread/mutex.hpp>
 #include <map>
 #include <string>
 #include "sync-digest.h"
@@ -37,7 +39,7 @@
 class NameInfo
 {
 private:
-  typedef boost::shared_ptr<const NameInfo> const_ptr;
+  typedef boost::weak_ptr<const NameInfo> const_weak_ptr;
   
 public:
   virtual ~NameInfo () { };
@@ -74,21 +76,28 @@
    */
   virtual std::string
   toString () const = 0;
-
+  
 protected:
   // actual stuff
   size_t m_id; ///< @brief Identifies NameInfo throughout the library (for hash container, doesn't need to be strictly unique)
   Digest m_digest;
 
   // static stuff
-  typedef std::map<std::string, const_ptr> NameMap;
+  typedef std::map<std::string, const_weak_ptr> NameMap;
   static size_t  m_ids;
   static NameMap m_names;
+  static boost::mutex m_namesMutex;
 };
 
 typedef boost::shared_ptr<NameInfo> NameInfoPtr;
 typedef boost::shared_ptr<const NameInfo> NameInfoConstPtr;
 
+inline std::ostream &
+operator << (std::ostream &os, const NameInfo &info)
+{
+  os << info.toString ();
+  return os;
+}
 
 } // Sync
 
diff --git a/model/sync-ns3-name-info.cc b/model/sync-ns3-name-info.cc
index d1c8e31..9e0ef78 100644
--- a/model/sync-ns3-name-info.cc
+++ b/model/sync-ns3-name-info.cc
@@ -27,6 +27,7 @@
 
 #include <boost/foreach.hpp>
 #include <boost/lexical_cast.hpp>
+#include <boost/make_shared.hpp>
 #include <utility>
 
 using namespace std;
@@ -40,11 +41,17 @@
 {
   string key = lexical_cast<string> (*name);
 
-  NameInfoPtr value = NameInfoPtr (new Ns3NameInfo (name));
-  pair<NameMap::iterator,bool> item =
-    m_names.insert (make_pair (key, value));
+  NameMap::iterator item = m_names.find (key);
+  if (item == m_names.end ())
+    {
+      NameInfoPtr value = NameInfoPtr (new Ns3NameInfo (name));
+      pair<NameMap::iterator,bool> inserted =
+        m_names.insert (make_pair (key, value));
+      BOOST_ASSERT (inserted.second); // previous call has to insert value
+      item = inserted.first;
+    }
 
-  return item.first->second;
+  return item->second;
 }
 
 Ns3NameInfo::Ns3NameInfo (ns3::Ptr<const ns3::CcnxNameComponents> name)
diff --git a/model/sync-seq-no.h b/model/sync-seq-no.h
index 354a1b6..ae7f355 100644
--- a/model/sync-seq-no.h
+++ b/model/sync-seq-no.h
@@ -139,6 +139,13 @@
   uint32_t m_seq;
 };
 
+inline std::ostream &
+operator << (std::ostream &os, const SeqNo &seqno)
+{
+  os << seqno.getSession () << ":" << seqno.getSeq ();
+  return os;
+}
+
 } // Sync
 
 #endif // SYNC_SEQ_NO_H
diff --git a/model/sync-state.cc b/model/sync-state.cc
index 2680859..268a45f 100644
--- a/model/sync-state.cc
+++ b/model/sync-state.cc
@@ -19,3 +19,10 @@
  *         卞超轶 Chaoyi Bian <bcy@pku.edu.cn>
  *	   Alexander Afanasyev <alexander.afanasyev@ucla.edu>
  */
+
+#include "sync-state.h"
+#include <boost/assert.hpp>
+
+namespace Sync {
+
+}
diff --git a/model/sync-state.h b/model/sync-state.h
index 0576af2..03d4ec4 100644
--- a/model/sync-state.h
+++ b/model/sync-state.h
@@ -52,7 +52,6 @@
 
   /**
    * @brief Remove leaf from the state tree
-   *
    * @param info name of the leaf
    */
   virtual void
diff --git a/model/sync-std-name-info.cc b/model/sync-std-name-info.cc
index 53fcdac..762ecfd 100644
--- a/model/sync-std-name-info.cc
+++ b/model/sync-std-name-info.cc
@@ -21,8 +21,10 @@
  */
 
 #include "sync-std-name-info.h"
+#include "boost/thread/locks.hpp"
 
 using namespace std;
+using namespace boost;
 
 namespace Sync {
 
@@ -30,11 +32,30 @@
 NameInfoConstPtr
 StdNameInfo::FindOrCreate (const std::string &key)
 {
-  NameInfoPtr value = NameInfoPtr (new StdNameInfo (key));
-  pair<NameMap::iterator,bool> item =
-    m_names.insert (make_pair (key, value));
+  mutex::scoped_lock namesLock (m_namesMutex);
+  
+  // std::cout << "FindOrCreate: " << m_names.size () << "\n";
+  
+  NameInfoConstPtr ret;
+  
+  NameMap::iterator item = m_names.find (key);
+  if (item != m_names.end ())
+    {
+      ret = item->second.lock ();
+      BOOST_ASSERT (ret != 0);
+    }
+  else
+    {
+      ret = NameInfoPtr (new StdNameInfo (key));
+      weak_ptr<const NameInfo> value (ret);
+      pair<NameMap::iterator,bool> inserted =
+        m_names.insert (make_pair (key, value));
+      
+      BOOST_ASSERT (inserted.second); // previous call has to insert value
+      item = inserted.first;
+    }
 
-  return item.first->second;
+  return ret;
 }
 
 StdNameInfo::StdNameInfo (const std::string &name)
@@ -43,6 +64,16 @@
   m_id = m_ids ++; // set ID for a newly inserted element
   m_digest << name;
   m_digest.getHash (); // finalize digest
+
+  // std::cout << "StdNameInfo: " << name << " = " << m_id << "\n";
+}
+
+StdNameInfo::~StdNameInfo ()
+{
+  mutex::scoped_lock namesLock (m_namesMutex);
+
+  // cout << "Destructor for " << m_name << "\n";
+  m_names.erase (toString ());
 }
 
 string
diff --git a/model/sync-std-name-info.h b/model/sync-std-name-info.h
index 1821fb4..a70af38 100644
--- a/model/sync-std-name-info.h
+++ b/model/sync-std-name-info.h
@@ -38,7 +38,10 @@
   static NameInfoConstPtr
   FindOrCreate (const std::string &name);
 
-  virtual ~StdNameInfo () { };
+  /**
+   * @brief Destructor which will clean up m_names structure
+   */
+  virtual ~StdNameInfo ();
   
   // from NameInfo
   virtual bool