diff --git a/src/core/system-wall-clock-ms.h b/src/core/system-wall-clock-ms.h
index 0c512d3ad..9cca3ca38 100644
--- a/src/core/system-wall-clock-ms.h
+++ b/src/core/system-wall-clock-ms.h
@@ -25,6 +25,9 @@ namespace ns3 {
 
 /**
  * \brief measure wall-clock time in milliseconds
+
+ * \todo This class exists also in non-unix systems but is not
+ * implemented and always return zero as measurd time.
  */
 class SystemWallClockMs {
 public:
@@ -36,13 +39,31 @@ public:
    */
   void Start (void);
   /**
-   * \returns the measured elapsed wall clock time since 
-   *          ns3::SystemWallClockMs::start was invoked.
+   * \brief Stop measuring the time since Start() was called.
+   * \returns the measured elapsed wall clock time (in milliseconds) since 
+   *          ns3::SystemWallClockMs::Start was invoked.
    *
-   * It is possible to start a new measurement with ns3::SystemWallClockMs::start
+   * It is possible to start a new measurement with ns3::SystemWallClockMs::Start
    * after this method returns.
    */
   unsigned long long End (void);
+
+  /**
+   * \returns the measured elapsed wall clock time (in milliseconds) since 
+   *          ns3::SystemWallClockMs::Start was invoked.
+   */
+  double GetElapsedReal (void) const;
+  /**
+   * \returns the measured elapsed 'user' wall clock time (in milliseconds) since 
+   *          ns3::SystemWallClockMs::Start was invoked.
+   */
+  double GetElapsedUser (void) const;
+  /**
+   * \returns the measured elapsed 'system' wall clock time (in milliseconds) since 
+   *          ns3::SystemWallClockMs::Start was invoked.
+   */
+  double GetElapsedSystem (void) const;
+
 private:
   class SystemWallClockMsPrivate *m_priv;
 };
diff --git a/src/core/test.cc b/src/core/test.cc
index 57d285ad0..3b3a2db24 100644
--- a/src/core/test.cc
+++ b/src/core/test.cc
@@ -262,7 +262,7 @@ TestCase::ContinueOnFailure (void)
 void
 TestCase::DoReportStart  (void)
 {
-  m_startTime = times (&m_startTimes);
+  m_clock.Start ();
 
   if (m_ofs == 0)
     {
@@ -319,26 +319,18 @@ TestCase::DoReportTestFailure  (
 void
 TestCase::DoReportEnd  (void)
 {
-  static long ticksPerSecond = sysconf (_SC_CLK_TCK);
-
+  m_clock.End ();
   if (m_ofs == 0)
     {
       return;
     }
 
-  struct tms endTimes;
-  clock_t endTime = times (&endTimes);
-
-  clock_t elapsed = endTime - m_startTime;
-  clock_t elapsedUsr = endTimes.tms_utime - m_startTimes.tms_utime;
-  clock_t elapsedSys = endTimes.tms_stime - m_startTimes.tms_stime;
-
   (*m_ofs).precision (2);
   *m_ofs << std::fixed;
 
-  *m_ofs << "    <CaseTime>" << "real " << static_cast<double> (elapsed) / ticksPerSecond
-                             << " user " << static_cast<double> (elapsedUsr) / ticksPerSecond
-                             << " system " << static_cast<double> (elapsedSys) / ticksPerSecond
+  *m_ofs << "    <CaseTime>" << "real " << m_clock.GetElapsedReal () * 1e-3
+                             << " user " << m_clock.GetElapsedUser () * 1e-3
+                             << " system " << m_clock.GetElapsedSystem () * 1e-3
          << "</CaseTime>" << std::endl;
 
   *m_ofs << "  </TestCase>" << std::endl;
@@ -523,8 +515,8 @@ TestSuite::ContinueOnFailure (void)
 void
 TestSuite::DoReportStart (void)
 {
-  m_startTime = times (&m_startTimes);
-
+  m_clock.Start ();
+  
   if (m_ofs == 0)
     {
       return;
@@ -556,25 +548,19 @@ TestSuite::DoReportSuccess (void)
 void
 TestSuite::DoReportEnd (void)
 {
-  static long ticksPerSecond = sysconf (_SC_CLK_TCK);
-
+  m_clock.End ();
+  
   if (m_ofs == 0)
     {
       return;
     }
-  struct tms endTimes;
-  clock_t endTime = times (&endTimes);
-
-  clock_t elapsed = endTime - m_startTime;
-  clock_t elapsedUsr = endTimes.tms_utime - m_startTimes.tms_utime;
-  clock_t elapsedSys = endTimes.tms_stime - m_startTimes.tms_stime;
 
   (*m_ofs).precision (2);
   *m_ofs << std::fixed;
 
-  *m_ofs << "  <SuiteTime>" << "real " << static_cast<double> (elapsed) / ticksPerSecond
-                            << " user " << static_cast<double> (elapsedUsr) / ticksPerSecond
-                            << " system " << static_cast<double> (elapsedSys) / ticksPerSecond
+  *m_ofs << "  <SuiteTime>" << "real " << m_clock.GetElapsedReal () * 1e-3
+                            << " user " << m_clock.GetElapsedUser () * 1e-3
+                            << " system " << m_clock.GetElapsedSystem () * 1e-3
          << "</SuiteTime>" << std::endl;
 
   *m_ofs << "</TestSuite>" << std::endl;
diff --git a/src/core/test.h b/src/core/test.h
index 58db025f9..1a6e77950 100644
--- a/src/core/test.h
+++ b/src/core/test.h
@@ -27,7 +27,10 @@
 #include <list>
 #include <limits>
 #include <stdint.h>
-#include <sys/times.h>
+
+#include "ns3/system-wall-clock-ms.h"
+
+
 // 
 // Note on below macros:
 //
@@ -821,6 +824,7 @@ private:
   TestCase (TestCase& tc);
   TestCase& operator= (TestCase& tc);
 
+  SystemWallClockMs m_clock;
   std::string m_name;
   bool m_verbose;
   bool m_continueOnFailure;
@@ -828,8 +832,6 @@ private:
   std::string m_basedir;
   std::ofstream *m_ofs;
   bool m_error;
-  clock_t m_startTime;
-  struct tms m_startTimes;
 };
 
 /**
@@ -1057,6 +1059,7 @@ private:
   TestSuite (TestSuite& ts);
   TestSuite& operator= (TestSuite& ts);
 
+  SystemWallClockMs m_clock;
   std::string m_name;
   bool m_verbose;
   bool m_continueOnFailure;
@@ -1064,10 +1067,7 @@ private:
   std::ofstream *m_ofs;
   bool m_error;
   TestType m_type;
-
-  clock_t m_startTime;
-  struct tms m_startTimes;
-
+  
   typedef std::vector<TestCase *> TestCaseVector_t;
   TestCaseVector_t m_tests;
 };
diff --git a/src/core/unix-system-wall-clock-ms.cc b/src/core/unix-system-wall-clock-ms.cc
index 14f1fbb5b..cfe53932f 100644
--- a/src/core/unix-system-wall-clock-ms.cc
+++ b/src/core/unix-system-wall-clock-ms.cc
@@ -19,7 +19,9 @@
  */
 
 #include "system-wall-clock-ms.h"
-#include <sys/time.h>
+#include <sys/times.h>
+#include <unistd.h>
+#include <limits.h>
 
 namespace ns3 {
 
@@ -27,28 +29,57 @@ class SystemWallClockMsPrivate {
 public:
   void Start (void);
   unsigned long long End (void);
+  double GetElapsedReal (void) const;
+  double GetElapsedUser (void) const;
+  double GetElapsedSystem (void) const;
+
 private:
-  struct timeval m_startTv;
-  struct timeval m_endTv;
+  struct tms m_startTimes;
+  clock_t m_startTime;
+  double m_elapsedReal;
+  double m_elapsedUser;
+  double m_elapsedSystem;
 };
 
 void 
 SystemWallClockMsPrivate::Start (void)
 {
-  struct timezone tz;
-  gettimeofday (&m_startTv, &tz);
+  m_startTime = times (&m_startTimes);
 }
 
 unsigned long long 
 SystemWallClockMsPrivate::End (void)
 {
-  struct timezone tz;
-  gettimeofday (&m_endTv, &tz);
-  unsigned long long end = m_endTv.tv_sec *1000 + m_endTv.tv_usec / 1000;
-  unsigned long long start = m_startTv.tv_sec *1000 + m_startTv.tv_usec / 1000;
-  return end - start;
+  static long ticksPerSecond = sysconf (_SC_CLK_TCK);
+
+  struct tms endTimes;
+  clock_t endTime = times (&endTimes);
+
+  m_elapsedReal = 1e3 * static_cast<double> (endTime - m_startTime) / ticksPerSecond;
+  m_elapsedUser = 1e3 * static_cast<double> (endTimes.tms_utime - m_startTimes.tms_utime) / ticksPerSecond;
+  m_elapsedSystem = 1e3 * static_cast<double> (endTimes.tms_stime - m_startTimes.tms_stime) / ticksPerSecond;
+
+  return m_elapsedReal;
 }
 
+double
+SystemWallClockMsPrivate::GetElapsedReal (void) const
+{
+  return m_elapsedReal;
+}
+
+double
+SystemWallClockMsPrivate::GetElapsedUser (void) const
+{
+  return m_elapsedUser;
+}
+
+double
+SystemWallClockMsPrivate::GetElapsedSystem (void) const
+{
+  return m_elapsedSystem;
+}
+  
 SystemWallClockMs::SystemWallClockMs ()
   : m_priv (new SystemWallClockMsPrivate ())
 {}
@@ -70,4 +101,22 @@ SystemWallClockMs::End (void)
   return m_priv->End ();
 }
 
+double
+SystemWallClockMs::GetElapsedReal (void) const
+{
+  return m_priv->GetElapsedReal ();
+}
+
+double
+SystemWallClockMs::GetElapsedUser (void) const
+{
+  return m_priv->GetElapsedUser ();
+}
+
+double
+SystemWallClockMs::GetElapsedSystem (void) const
+{
+  return m_priv->GetElapsedSystem ();
+}
+
 }; // namespace ns3
diff --git a/src/core/win32-system-wall-clock-ms.cc b/src/core/win32-system-wall-clock-ms.cc
index 1cc9fc2c5..c02f0f268 100644
--- a/src/core/win32-system-wall-clock-ms.cc
+++ b/src/core/win32-system-wall-clock-ms.cc
@@ -61,4 +61,22 @@ SystemWallClockMs::End (void)
   return m_priv->End ();
 }
 
+double
+SystemWallClockMs::GetElapsedReal (void) const
+{
+  return 0;
+}
+
+double
+SystemWallClockMs::GetElapsedUser (void) const
+{
+  return 0;
+}
+
+double
+SystemWallClockMs::GetElapsedSystem (void) const
+{
+  return 0;
+}
+
 }; // namespace ns3