diff --git a/src/internet/model/tcp-socket-base.cc b/src/internet/model/tcp-socket-base.cc
index 07bbf0d7b..b531aaf9c 100644
--- a/src/internet/model/tcp-socket-base.cc
+++ b/src/internet/model/tcp-socket-base.cc
@@ -2164,6 +2164,9 @@ TcpSocketBase::SendEmptyPacket (uint8_t flags)
           UpdateRttHistory (s, 0, true);
         }
     }
+
+  m_txTrace (p, header, this);
+
   if (m_endPoint != 0)
     {
       m_tcp->SendPacket (p, header, m_endPoint->GetLocalAddress (),
@@ -2175,8 +2178,6 @@ TcpSocketBase::SendEmptyPacket (uint8_t flags)
                          m_endPoint6->GetPeerAddress (), m_boundnetdevice);
     }
 
-  m_txTrace (p, header, this);
-
   if (flags & TcpHeader::ACK)
     { // If sending an ACK, cancel the delay ACK as well
       m_delAckEvent.Cancel ();
@@ -2447,6 +2448,8 @@ TcpSocketBase::SendDataPacket (SequenceNumber32 seq, uint32_t maxSize, bool with
       m_retxEvent = Simulator::Schedule (m_rto, &TcpSocketBase::ReTxTimeout, this);
     }
 
+  m_txTrace (p, header, this);
+
   if (m_endPoint)
     {
       m_tcp->SendPacket (p, header, m_endPoint->GetLocalAddress (),
@@ -2464,8 +2467,6 @@ TcpSocketBase::SendDataPacket (SequenceNumber32 seq, uint32_t maxSize, bool with
                     ". Header " << header);
     }
 
-  m_txTrace (p, header, this);
-
   UpdateRttHistory (seq, sz, isRetransmission);
 
   // Notify the application of the data being sent unless this is a retransmit
@@ -2834,6 +2835,8 @@ TcpSocketBase::PersistTimeout ()
     }
   AddOptions (tcpHeader);
 
+  m_txTrace (p, tcpHeader, this);
+
   if (m_endPoint != 0)
     {
       m_tcp->SendPacket (p, tcpHeader, m_endPoint->GetLocalAddress (),
@@ -2845,8 +2848,6 @@ TcpSocketBase::PersistTimeout ()
                          m_endPoint6->GetPeerAddress (), m_boundnetdevice);
     }
 
-  m_txTrace (p, tcpHeader, this);
-
   NS_LOG_LOGIC ("Schedule persist timeout at time "
                 << Simulator::Now ().GetSeconds () << " to expire at time "
                 << (Simulator::Now () + m_persistTimeout).GetSeconds ());
diff --git a/src/internet/test/tcp-zero-window-test.cc b/src/internet/test/tcp-zero-window-test.cc
index ad11dd1fb..d9213a2af 100644
--- a/src/internet/test/tcp-zero-window-test.cc
+++ b/src/internet/test/tcp-zero-window-test.cc
@@ -89,7 +89,7 @@ TcpZeroWindowTest::Tx (const Ptr<const Packet> p, const TcpHeader &h, SocketWho
 
       if (Simulator::Now ().GetSeconds () <= 6.0)
         {
-          NS_TEST_ASSERT_MSG_EQ (p->GetSize () - h.GetSerializedSize (), 0,
+          NS_TEST_ASSERT_MSG_EQ (p->GetSize (), 0,
                                  "Data packet sent anyway");
         }
       else if (Simulator::Now ().GetSeconds () > 6.0
@@ -99,7 +99,7 @@ TcpZeroWindowTest::Tx (const Ptr<const Packet> p, const TcpHeader &h, SocketWho
 
           if (!m_zeroWindowProbe)
             {
-              NS_TEST_ASSERT_MSG_EQ (p->GetSize () - h.GetSerializedSize (), 1,
+              NS_TEST_ASSERT_MSG_EQ (p->GetSize (), 1,
                                      "Data packet sent instead of window probe");
               NS_TEST_ASSERT_MSG_EQ (h.GetSequenceNumber (), SequenceNumber32 (1),
                                      "Data packet sent instead of window probe");