diff --git a/src/applications/model/three-gpp-http-client.cc b/src/applications/model/three-gpp-http-client.cc
index 79a3bff57..fc5dcf83b 100644
--- a/src/applications/model/three-gpp-http-client.cc
+++ b/src/applications/model/three-gpp-http-client.cc
@@ -212,6 +212,7 @@ ThreeGppHttpClient::StartApplication ()
 
   if (m_state == NOT_STARTED)
     {
+      m_httpVariables->Initialize ();
       OpenConnection ();
     }
   else
diff --git a/src/applications/model/three-gpp-http-server.cc b/src/applications/model/three-gpp-http-server.cc
index fe3e1601c..a365230d7 100644
--- a/src/applications/model/three-gpp-http-server.cc
+++ b/src/applications/model/three-gpp-http-server.cc
@@ -203,6 +203,7 @@ ThreeGppHttpServer::StartApplication ()
 
   if (m_state == NOT_STARTED)
     {
+      m_httpVariables->Initialize ();
       if (m_initialSocket == 0)
         {
           // Find the current default MTU value of TCP sockets.
diff --git a/src/applications/model/three-gpp-http-variables.cc b/src/applications/model/three-gpp-http-variables.cc
index dde9a03f7..ad80eef14 100644
--- a/src/applications/model/three-gpp-http-variables.cc
+++ b/src/applications/model/three-gpp-http-variables.cc
@@ -339,6 +339,13 @@ ThreeGppHttpVariables::AssignStreams (int64_t stream)
   return 9;
 }
 
+void
+ThreeGppHttpVariables::DoInitialize (void)
+{
+  NS_LOG_FUNCTION (this);
+  UpdateMainObjectMuAndSigma ();
+  UpdateEmbeddedObjectMuAndSigma ();
+}
 
 // SETTER METHODS /////////////////////////////////////////////////////////////
 
@@ -360,15 +367,10 @@ ThreeGppHttpVariables::SetMainObjectGenerationDelay (Time constant)
                                                 DoubleValue (constant.GetSeconds ()));
 }
 
-
 void
-ThreeGppHttpVariables::SetMainObjectSizeMean (uint32_t mean)
+ThreeGppHttpVariables::UpdateMainObjectMuAndSigma (void)
 {
-  NS_LOG_FUNCTION (this << mean);
-  NS_ASSERT_MSG (mean > 0, "Mean must be greater than zero.");
-  m_mainObjectSizeMean = mean;
-
-  // Update Mu and Sigma.
+  NS_LOG_FUNCTION (this);
   const double a1 = std::pow (m_mainObjectSizeStdDev, 2.0);
   const double a2 = std::pow (m_mainObjectSizeMean, 2.0);
   const double a = std::log (1.0 + (a1 / a2));
@@ -379,22 +381,44 @@ ThreeGppHttpVariables::SetMainObjectSizeMean (uint32_t mean)
   m_mainObjectSizeRng->SetAttribute ("Sigma", DoubleValue (sigma));
 }
 
+void
+ThreeGppHttpVariables::UpdateEmbeddedObjectMuAndSigma (void)
+{
+  NS_LOG_FUNCTION (this);
+  const double a1 = std::pow (m_embeddedObjectSizeStdDev, 2.0);
+  const double a2 = std::pow (m_embeddedObjectSizeMean, 2.0);
+  const double a = std::log (1.0 + (a1 / a2));
+  const double mu = std::log (m_embeddedObjectSizeMean) - (0.5 * a);
+  const double sigma = std::sqrt (a);
+  NS_LOG_DEBUG (this << " Mu= " << mu << " Sigma= " << sigma << ".");
+  m_embeddedObjectSizeRng->SetAttribute ("Mu", DoubleValue (mu));
+  m_embeddedObjectSizeRng->SetAttribute ("Sigma", DoubleValue (sigma));
+}
+
+void
+ThreeGppHttpVariables::SetMainObjectSizeMean (uint32_t mean)
+{
+  NS_LOG_FUNCTION (this << mean);
+  NS_ASSERT_MSG (mean > 0, "Mean must be greater than zero.");
+  m_mainObjectSizeMean = mean;
+
+  if (IsInitialized ())
+    {
+      UpdateMainObjectMuAndSigma ();
+    }
+}
+
 
 void
 ThreeGppHttpVariables::SetMainObjectSizeStdDev (uint32_t stdDev)
 {
   NS_LOG_FUNCTION (this << stdDev);
   m_mainObjectSizeStdDev = stdDev;
-
-  // Update Mu and Sigma. Same piece of code as in SetMainObjectSizeMean().
-  const double a1 = std::pow (m_mainObjectSizeStdDev, 2.0);
-  const double a2 = std::pow (m_mainObjectSizeMean, 2.0);
-  const double a = std::log (1.0 + (a1 / a2));
-  const double mu = std::log (m_mainObjectSizeMean) - (0.5 * a);
-  const double sigma = std::sqrt (a);
-  NS_LOG_DEBUG (this << " Mu= " << mu << " Sigma= " << sigma << ".");
-  m_mainObjectSizeRng->SetAttribute ("Mu", DoubleValue (mu));
-  m_mainObjectSizeRng->SetAttribute ("Sigma", DoubleValue (sigma));
+  
+  if (IsInitialized ())
+    {
+      UpdateMainObjectMuAndSigma ();
+    }
 }
 
 
@@ -414,15 +438,10 @@ ThreeGppHttpVariables::SetEmbeddedObjectSizeMean (uint32_t mean)
   NS_ASSERT_MSG (mean > 0, "Mean must be greater than zero.");
   m_embeddedObjectSizeMean = mean;
 
-  // Update Mu and Sigma.
-  const double a1 = std::pow (m_embeddedObjectSizeStdDev, 2.0);
-  const double a2 = std::pow (m_embeddedObjectSizeMean, 2.0);
-  const double a = std::log (1.0 + (a1 / a2));
-  const double mu = std::log (m_embeddedObjectSizeMean) - (0.5 * a);
-  const double sigma = std::sqrt (a);
-  NS_LOG_DEBUG (this << " Mu= " << mu << " Sigma= " << sigma << ".");
-  m_embeddedObjectSizeRng->SetAttribute ("Mu", DoubleValue (mu));
-  m_embeddedObjectSizeRng->SetAttribute ("Sigma", DoubleValue (sigma));
+  if (IsInitialized ())
+    {
+      UpdateEmbeddedObjectMuAndSigma ();
+    }
 }
 
 
@@ -432,15 +451,10 @@ ThreeGppHttpVariables::SetEmbeddedObjectSizeStdDev (uint32_t stdDev)
   NS_LOG_FUNCTION (this << stdDev);
   m_embeddedObjectSizeStdDev = stdDev;
 
-  // Update Mu and Sigma. Same piece of code as in SetEmbeddedObjectSizeMean().
-  const double a1 = std::pow (m_embeddedObjectSizeStdDev, 2.0);
-  const double a2 = std::pow (m_embeddedObjectSizeMean, 2.0);
-  const double a = std::log (1.0 + (a1 / a2));
-  const double mu = std::log (m_embeddedObjectSizeMean) - (0.5 * a);
-  const double sigma = std::sqrt (a);
-  NS_LOG_DEBUG (this << " Mu= " << mu << " Sigma= " << sigma << ".");
-  m_embeddedObjectSizeRng->SetAttribute ("Mu", DoubleValue (mu));
-  m_embeddedObjectSizeRng->SetAttribute ("Sigma", DoubleValue (sigma));
+  if (IsInitialized ())
+    {
+      UpdateEmbeddedObjectMuAndSigma ();
+    }
 }
 
 
diff --git a/src/applications/model/three-gpp-http-variables.h b/src/applications/model/three-gpp-http-variables.h
index a862fa8a4..a1df1fd4e 100644
--- a/src/applications/model/three-gpp-http-variables.h
+++ b/src/applications/model/three-gpp-http-variables.h
@@ -267,6 +267,19 @@ public:
   void SetParsingTimeMean (Time mean);
 
 private:
+  /**
+   * \brief Upon and after object initialization, update random variable
+   * Mu and Sigma based on changes to attribute values.
+   */
+  void UpdateMainObjectMuAndSigma (void);
+  /**
+   * \brief Upon and after object initialization, update random variable
+   * Mu and Sigma based on changes to attribute values.
+   */
+  void UpdateEmbeddedObjectMuAndSigma (void);
+  
+  void DoInitialize (void);   // overridden from base class
+
   /**
    * Random variable for determining MTU size (in bytes).
    */
@@ -330,7 +343,7 @@ private:
    */
   Ptr<ExponentialRandomVariable>  m_parsingTimeRng;
 
-}; // end of `class TreeGppHttpVariables`
+}; // end of `class ThreeGppHttpVariables`
 
 
 } // end of `namespace ns3`