diff --git a/utils/counting-policy.h b/utils/counting-policy.h
index b7d992e..d8cfe07 100644
--- a/utils/counting-policy.h
+++ b/utils/counting-policy.h
@@ -24,6 +24,8 @@
 #include <boost/intrusive/options.hpp>
 #include <boost/intrusive/list.hpp>
 
+namespace ns3
+{
 namespace ndnSIM
 {
 
@@ -103,5 +105,6 @@
 };
 
 } // ndnSIM
+} // ns3
 
 #endif // COUNTING_POLICY_H_
diff --git a/utils/detail/functor-hook.h b/utils/detail/functor-hook.h
index 94b8b8f..63dcffd 100644
--- a/utils/detail/functor-hook.h
+++ b/utils/detail/functor-hook.h
@@ -23,6 +23,8 @@
 
 #include <boost/intrusive/parent_from_member.hpp>
 
+namespace ns3
+{
 namespace ndnSIM
 {
 namespace detail
@@ -64,5 +66,6 @@
 
 } // detail
 } // ndnSIM
+} // ns3
 
 #endif // FUNCTOR_HOOK_H_
diff --git a/utils/detail/multi-policy-container.h b/utils/detail/multi-policy-container.h
index 0fa07b3..7272a01 100644
--- a/utils/detail/multi-policy-container.h
+++ b/utils/detail/multi-policy-container.h
@@ -24,6 +24,8 @@
 #include <boost/mpl/inherit_linearly.hpp>
 #include <boost/mpl/at.hpp>
 
+namespace ns3
+{
 namespace ndnSIM
 {
 namespace detail
@@ -158,5 +160,6 @@
 
 } // detail
 } // ndnSIM
+} // ns3
 
 #endif // MULTI_POLICY_CONTAINER_H_
diff --git a/utils/detail/multi-type-container.h b/utils/detail/multi-type-container.h
index 43a25da..24bf17c 100644
--- a/utils/detail/multi-type-container.h
+++ b/utils/detail/multi-type-container.h
@@ -25,6 +25,8 @@
 #include <boost/mpl/inherit.hpp>
 #include <boost/mpl/at.hpp>
 
+namespace ns3
+{
 namespace ndnSIM
 {
 namespace detail
@@ -80,5 +82,6 @@
   
 } // detail
 } // ndnSIM
+} // ns3
 
 #endif // MULTI_TYPE_CONTAINER_H_
diff --git a/utils/empty-policy.h b/utils/empty-policy.h
index a04507d..04bc676 100644
--- a/utils/empty-policy.h
+++ b/utils/empty-policy.h
@@ -21,6 +21,8 @@
 #ifndef EMPTY_POLICY_H_
 #define EMPTY_POLICY_H_
 
+namespace ns3
+{
 namespace ndnSIM
 {
 
@@ -51,6 +53,7 @@
   };
 };
 
-}
+} // ndnSIM
+} // ns3
 
 #endif // EMPTY_POLICY_H_
diff --git a/utils/fifo-policy.h b/utils/fifo-policy.h
index 7286524..1943e06 100644
--- a/utils/fifo-policy.h
+++ b/utils/fifo-policy.h
@@ -24,6 +24,8 @@
 #include <boost/intrusive/options.hpp>
 #include <boost/intrusive/list.hpp>
 
+namespace ns3
+{
 namespace ndnSIM
 {
 
@@ -121,5 +123,6 @@
 };
 
 } // ndnSIM
+} // ns3
 
 #endif
diff --git a/utils/load-stats-face.cc b/utils/load-stats-face.cc
index 53edb6a..de202ee 100644
--- a/utils/load-stats-face.cc
+++ b/utils/load-stats-face.cc
@@ -30,6 +30,8 @@
 
 NS_LOG_COMPONENT_DEFINE ("LoadStatsFace");
 
+namespace ns3
+{
 namespace ndnSIM
 {
 
@@ -145,4 +147,6 @@
   return os;
 }
 
-}
+} // ndnSIM
+} // ns3
+
diff --git a/utils/load-stats-face.h b/utils/load-stats-face.h
index a930181..b8202f9 100644
--- a/utils/load-stats-face.h
+++ b/utils/load-stats-face.h
@@ -23,6 +23,8 @@
 
 #include "load-stats.h"
 
+namespace ns3
+{
 namespace ndnSIM
 {
 
@@ -130,6 +132,7 @@
 std::ostream &
 operator << (std::ostream &os, const LoadStatsFace &stats);
 
-}
+} // ndnSIM
+} // ns3
 
 #endif // LOAD_STATS_FACE_H
diff --git a/utils/load-stats-node.cc b/utils/load-stats-node.cc
index 9514a84..86a149d 100644
--- a/utils/load-stats-node.cc
+++ b/utils/load-stats-node.cc
@@ -26,10 +26,10 @@
 
 namespace ll = boost::lambda;
 
-using namespace ns3;
-
 NS_LOG_COMPONENT_DEFINE ("LoadStatsNode");
 
+namespace ns3
+{
 namespace ndnSIM
 {
 
@@ -213,4 +213,5 @@
 }
 
 
-}
+} // ndnSIM
+} // ns3
diff --git a/utils/load-stats-node.h b/utils/load-stats-node.h
index b0b580d..5989a23 100644
--- a/utils/load-stats-node.h
+++ b/utils/load-stats-node.h
@@ -28,7 +28,6 @@
 namespace ns3
 {
 class NdnFace;
-}
 
 namespace ndnSIM
 {
@@ -152,6 +151,7 @@
 std::ostream&
 operator << (std::ostream &os, const LoadStatsNode &node);
 
-}
+} // ndnSIM
+} // ns3
 
 #endif
diff --git a/utils/load-stats.cc b/utils/load-stats.cc
index 2fca525..166a906 100644
--- a/utils/load-stats.cc
+++ b/utils/load-stats.cc
@@ -21,8 +21,6 @@
 #include "load-stats.h"
 #include "ns3/log.h"
 
-using namespace ns3;
-
 // const double EXP_1  = (1-2.0/6.0);//exp (-1.0/5.0);  /* 1/exp(1sec/5sec) */
 // const double EXP_2  = (1-2.0/31.0);//exp (-1.0/30.0); /* 1/exp(1sec/30sec) */
 // const double EXP_3 = (1-2.0/61.0);//exp (-1.0/60.0); /* 1/exp(1sec/60sec) */
@@ -33,6 +31,8 @@
 
 NS_LOG_COMPONENT_DEFINE ("LoadStats");
 
+namespace ns3
+{
 namespace ndnSIM
 {
 
@@ -105,3 +105,4 @@
 }
 
 } // ndnSIM
+} // ns3
diff --git a/utils/load-stats.h b/utils/load-stats.h
index abd09a0..2b2db89 100644
--- a/utils/load-stats.h
+++ b/utils/load-stats.h
@@ -24,6 +24,8 @@
 #include "ns3/nstime.h"
 #include <boost/tuple/tuple.hpp>
 
+namespace ns3
+{
 namespace ndnSIM
 {
 
@@ -75,5 +77,6 @@
 operator << (std::ostream &os, const LoadStats &stats);
 
 } // ndnSIM
+} // ns3
 
 #endif // LOAD_STATS_H
diff --git a/utils/lru-policy.h b/utils/lru-policy.h
index f828801..bddb281 100644
--- a/utils/lru-policy.h
+++ b/utils/lru-policy.h
@@ -24,6 +24,8 @@
 #include <boost/intrusive/options.hpp>
 #include <boost/intrusive/list.hpp>
 
+namespace ns3
+{
 namespace ndnSIM
 {
 
@@ -126,5 +128,6 @@
 };
 
 } // ndnSIM
+} // ns3
 
 #endif
diff --git a/utils/multi-policy.h b/utils/multi-policy.h
index f5cf682..b50119a 100644
--- a/utils/multi-policy.h
+++ b/utils/multi-policy.h
@@ -34,6 +34,8 @@
 
 #include <boost/intrusive/options.hpp>
 
+namespace ns3
+{
 namespace ndnSIM
 {
 
@@ -126,5 +128,6 @@
 };
 
 } // ndnSIM
+} // ns3
 
 #endif // MULTI_POLICY_H_
diff --git a/utils/payload-policy.h b/utils/payload-policy.h
index 5eb384a..76cf2cf 100644
--- a/utils/payload-policy.h
+++ b/utils/payload-policy.h
@@ -24,6 +24,8 @@
 #include <boost/intrusive/options.hpp>
 #include <boost/intrusive/list.hpp>
 
+namespace ns3
+{
 namespace ndnSIM
 {
 
@@ -127,5 +129,6 @@
 };
 
 } // ndnSIM
+} // ns3
 
 #endif // PAYLOAD_POLICY_H
diff --git a/utils/payload-with-policy.h b/utils/payload-with-policy.h
index 9fd6709..4cfe975 100644
--- a/utils/payload-with-policy.h
+++ b/utils/payload-with-policy.h
@@ -21,6 +21,8 @@
 #ifndef PAYLOAD_WITH_INDEX_H_
 #define PAYLOAD_WITH_INDEX_H_
 
+namespace ns3
+{
 namespace ndnSIM
 {
 
@@ -100,5 +102,6 @@
 };
 
 } // ndnSIM
+} // ns3
 
 #endif // PAYLOAD_WITH_POLICY_H_
diff --git a/utils/persistent-policy.h b/utils/persistent-policy.h
index fb72864..c7add54 100644
--- a/utils/persistent-policy.h
+++ b/utils/persistent-policy.h
@@ -24,6 +24,8 @@
 #include <boost/intrusive/options.hpp>
 #include <boost/intrusive/list.hpp>
 
+namespace ns3
+{
 namespace ndnSIM
 {
 
@@ -121,5 +123,6 @@
 };
 
 } // ndnSIM
+} // ns3
 
 #endif // PERSISTENT_POLICY_H_
diff --git a/utils/random-policy.h b/utils/random-policy.h
index c745b3b..3bfb6e2 100644
--- a/utils/random-policy.h
+++ b/utils/random-policy.h
@@ -26,6 +26,8 @@
 #include <boost/intrusive/options.hpp>
 #include <boost/intrusive/set.hpp>
 
+namespace ns3
+{
 namespace ndnSIM
 {
 
@@ -159,5 +161,6 @@
 };
 
 } // ndnSIM
+} // ns3
 
 #endif // RANDOM_POLICY_H
diff --git a/utils/stats-tree.cc b/utils/stats-tree.cc
index 7a7116c..aff2e93 100644
--- a/utils/stats-tree.cc
+++ b/utils/stats-tree.cc
@@ -26,6 +26,8 @@
 
 NS_LOG_COMPONENT_DEFINE ("StatsTree");
 
+namespace ns3
+{
 namespace ndnSIM
 {
 
@@ -156,4 +158,6 @@
 }
 
 
-}
+} // ndnSIM
+} // ns3
+
diff --git a/utils/stats-tree.h b/utils/stats-tree.h
index c6bf97a..c92d4bb 100644
--- a/utils/stats-tree.h
+++ b/utils/stats-tree.h
@@ -26,6 +26,8 @@
 #include "ns3/ndn-name-components.h"
 #include "ns3/ptr.h"
 
+namespace ns3
+{
 namespace ndnSIM
 {
 
@@ -85,5 +87,6 @@
 operator << (std::ostream &os, const StatsTree &tree);
 
 } // ndnSIM
+} // ns3
 
 #endif // STATS_TREE_H
diff --git a/utils/trie-with-policy.h b/utils/trie-with-policy.h
index bb5a668..12168ea 100644
--- a/utils/trie-with-policy.h
+++ b/utils/trie-with-policy.h
@@ -23,6 +23,8 @@
 
 #include "trie.h"
 
+namespace ns3
+{
 namespace ndnSIM
 {
 
@@ -234,5 +236,6 @@
 };
 
 } // ndnSIM
+} // ns3
 
 #endif // TRIE_WITH_POLICY_H_
diff --git a/utils/trie.h b/utils/trie.h
index c131f49..fe52d59 100644
--- a/utils/trie.h
+++ b/utils/trie.h
@@ -32,6 +32,8 @@
 #include <boost/foreach.hpp>
 #include <boost/mpl/if.hpp>
 
+namespace ns3
+{
 namespace ndnSIM
 {
 
@@ -640,5 +642,6 @@
 
 
 } // ndnSIM
+} // ns3
 
 #endif // TRIE_H_