--- a/src/internet/model/nsc-tcp-socket-impl.cc	Tue Mar 15 12:17:06 2011 +0100
+++ a/src/internet/model/nsc-tcp-socket-impl.cc	Wed Mar 16 15:19:48 2011 -0400
@@ -63,7 +63,8 @@ 
 }
 
 NscTcpSocketImpl::NscTcpSocketImpl ()
-  : m_endPoint (0),
+  : m_nagle (false),
+    m_endPoint (0),
     m_node (0),
     m_tcp (0),
     m_localAddress (Ipv4Address::GetZero ()),
@@ -85,6 +86,7 @@ 
   : TcpSocket(sock), //copy the base class callbacks
     m_delAckMaxCount (sock.m_delAckMaxCount),
     m_delAckTimeout (sock.m_delAckTimeout),
+    m_nagle (sock.m_nagle),
     m_endPoint (0),
     m_node (sock.m_node),
     m_tcp (sock.m_tcp),
@@ -794,6 +796,18 @@ 
   return m_delAckMaxCount;
 }
 
+void
+NscTcpSocketImpl::SetNagle (bool enable)
+{
+  m_nagle = enable;
+}
+
+bool
+NscTcpSocketImpl::GetNagle (void) const
+{
+  return m_nagle;
+}
+
 void 
 NscTcpSocketImpl::SetPersistTimeout (Time timeout)
 {
--- a/src/internet/model/nsc-tcp-socket-impl.h	Tue Mar 15 12:17:06 2011 +0100
+++ a/src/internet/model/nsc-tcp-socket-impl.h	Wed Mar 16 15:19:48 2011 -0400
@@ -124,6 +124,8 @@ 
   virtual void SetDelAckTimeout (Time timeout);
   virtual Time GetDelAckTimeout (void) const;
   virtual void SetDelAckMaxCount (uint32_t count);
+  virtual bool GetNagle (void) const;
+  virtual void SetNagle (bool enable);
   virtual uint32_t GetDelAckMaxCount (void) const;
   virtual void SetPersistTimeout (Time timeout);
   virtual Time GetPersistTimeout (void) const;
@@ -131,6 +133,7 @@ 
   enum Socket::SocketErrno GetNativeNs3Errno(int err) const;
   uint32_t m_delAckMaxCount;
   Time m_delAckTimeout;
+  bool m_nagle;
 
   Ipv4EndPoint *m_endPoint;
   Ptr<Node> m_node;
--- a/src/internet/model/rtt-estimator.cc	Tue Mar 15 12:17:06 2011 +0100
+++ a/src/internet/model/rtt-estimator.cc	Wed Mar 16 15:19:48 2011 -0400
@@ -53,7 +53,7 @@ 
                    MakeTimeChecker ())
     .AddAttribute ("MinRTO", 
                    "Minimum retransmit timeout value",
-                   TimeValue (Seconds (0.2)),
+                   TimeValue (Seconds (1)),
                    MakeTimeAccessor (&RttEstimator::minrto),
                    MakeTimeChecker ())
     ;
--- a/src/internet/model/tcp-socket-base.cc	Tue Mar 15 12:17:06 2011 +0100
+++ a/src/internet/model/tcp-socket-base.cc	Wed Mar 16 15:19:48 2011 -0400
@@ -83,6 +83,7 @@ 
 TcpSocketBase::TcpSocketBase (void)
   : m_dupAckCount (0),
     m_delAckCount (0),
+    m_nagle (true),
     m_endPoint (0),
     m_node (0),
     m_tcp (0),
@@ -109,6 +110,7 @@ 
     m_dupAckCount (sock.m_dupAckCount),
     m_delAckCount (0),
     m_delAckMaxCount (sock.m_delAckMaxCount),
+    m_nagle (sock.m_nagle),
     m_cnCount (sock.m_cnCount),
     m_delAckTimeout (sock.m_delAckTimeout),
     m_persistTimeout (sock.m_persistTimeout),
@@ -1296,6 +1298,16 @@ 
         {
           break; // No more
         }
+
+      // Nagle's algorithm. Hold off sending if there is unacked data in the 
+      // buffer and the amount of data to send is less than a segment size
+      if (UnAckDataCount () > 0 && 
+          m_txBuffer.SizeFromSequence (m_nextTxSequence) < m_segmentSize)
+        {
+          NS_LOG_LOGIC ("Invoking Nagle's algorithm. Wait to send.");
+          break;
+        }
+
       uint32_t s = std::min (w, m_segmentSize);  // Send no more than window
       Ptr<Packet> p = m_txBuffer.CopyFromSequence (s, m_nextTxSequence);
       NS_LOG_LOGIC ("TcpSocketBase " << this << " SendPendingData" <<
@@ -1732,6 +1744,18 @@ 
 }
 
 void
+TcpSocketBase::SetNagle (bool enable)
+{
+  m_nagle = enable;
+}
+
+bool
+TcpSocketBase::GetNagle (void) const
+{
+  return m_nagle;
+}
+
+void
 TcpSocketBase::SetPersistTimeout (Time timeout)
 {
   m_persistTimeout = timeout;
--- a/src/internet/model/tcp-socket-base.h	Tue Mar 15 12:17:06 2011 +0100
+++ a/src/internet/model/tcp-socket-base.h	Wed Mar 16 15:19:48 2011 -0400
@@ -115,6 +115,8 @@ 
   virtual Time     GetDelAckTimeout (void) const;
   virtual void     SetDelAckMaxCount (uint32_t count);
   virtual uint32_t GetDelAckMaxCount (void) const;
+  virtual void     SetNagle (bool enable);
+  virtual bool     GetNagle (void) const;
   virtual void     SetPersistTimeout (Time timeout);
   virtual Time     GetPersistTimeout (void) const;
   virtual bool     SetAllowBroadcast (bool allowBroadcast);
@@ -182,6 +184,7 @@ 
   uint32_t          m_dupAckCount;     //< Dupack counter
   uint32_t          m_delAckCount;     //< Delayed ACK counter
   uint32_t          m_delAckMaxCount;  //< Number of packet to fire an ACK before delay timeout
+  bool              m_nagle;           //< Enable or disable Nagle's algorithm
   uint32_t          m_cnCount;         //< Count of remaining connection retries
   TracedValue<Time> m_rto;             //< Retransmit timeout
   TracedValue<Time> m_lastRtt;         //< Last RTT sample collected
--- a/src/internet/model/tcp-socket.cc	Tue Mar 15 12:17:06 2011 +0100
+++ a/src/internet/model/tcp-socket.cc	Wed Mar 16 15:19:48 2011 -0400
@@ -22,6 +22,7 @@ 
 #include "ns3/log.h"
 #include "ns3/uinteger.h"
 #include "ns3/double.h"
+#include "ns3/boolean.h"
 #include "ns3/trace-source-accessor.h"
 #include "ns3/nstime.h"
 #include "tcp-socket.h"
@@ -93,6 +94,11 @@ 
                    MakeUintegerAccessor (&TcpSocket::GetDelAckMaxCount,
                                          &TcpSocket::SetDelAckMaxCount),
                    MakeUintegerChecker<uint32_t> ())
+    .AddAttribute ("Nagle", "Whether or not Nagle's algorithm is enabled",
+                   BooleanValue (true),
+                   MakeBooleanAccessor (&TcpSocket::SetNagle,
+                                        &TcpSocket::GetNagle),
+                   MakeBooleanChecker ())
     .AddAttribute ("PersistTimeout",
                    "Persist timeout to probe for rx window",
                    TimeValue (Seconds (6)),
--- a/src/internet/model/tcp-socket.h	Tue Mar 15 12:17:06 2011 +0100
+++ a/src/internet/model/tcp-socket.h	Wed Mar 16 15:19:48 2011 -0400
@@ -89,6 +89,8 @@ 
   virtual Time GetDelAckTimeout (void) const = 0;
   virtual void SetDelAckMaxCount (uint32_t count) = 0;
   virtual uint32_t GetDelAckMaxCount (void) const = 0;
+  virtual void SetNagle (bool enable) = 0;
+  virtual bool GetNagle (void) const = 0;
   virtual void SetPersistTimeout (Time timeout) = 0;
   virtual Time GetPersistTimeout (void) const = 0;