diff -r 6e16bf523c55 src/internet-stack/tcp-socket-impl.cc
--- a/src/internet-stack/tcp-socket-impl.cc	Wed Mar 03 08:33:26 2010 -0800
+++ b/src/internet-stack/tcp-socket-impl.cc	Thu Mar 04 12:32:01 2010 +0000
@@ -1501,7 +1501,7 @@
     }
   // See if all pending ack'ed; if so we can delete the data
   if (m_pendingData)
-    { // Data exists, see if can be deleted
+    { // Data exists, see if can be entirely deleted
       if (m_pendingData->SizeFromSeq (m_firstPendingSequence, m_highestRxAck) == 0)
         { // All pending acked, can be deleted
           m_pendingData->Clear ();
@@ -1513,6 +1513,24 @@
                         Simulator::GetDelayLeft (m_retxEvent)).GetSeconds());
           m_retxEvent.Cancel ();
         }
+      else // else delete just a portion
+        {
+          while (m_pendingData->data.begin () != m_pendingData->data.end ())
+            {
+              std::vector< Ptr<Packet> >::iterator dataI = m_pendingData->data.begin ();
+              Ptr<Packet> data = *dataI;
+              if (m_firstPendingSequence + SequenceNumber (data->GetSize ()) <= m_highestRxAck)
+                {
+                  m_pendingData->data.erase (dataI);
+                  m_pendingData->size -= data->GetSize ();
+                  m_firstPendingSequence += data->GetSize ();
+                }
+              else
+                {
+                  break;
+                }
+            }
+        }
     }
   // Try to send more data
   SendPendingData (m_connected);