--- a/src/internet/model/tcp-l4-protocol.cc	Tue Feb 09 19:29:52 2016 +0300
+++ a/src/internet/model/tcp-l4-protocol.cc	Mon Feb 15 09:45:55 2016 -0800
@@ -18,6 +18,8 @@ 
  * Author: Raj Bhattacharjea <raj.b@gatech.edu>
  */
 
+#define __STDC_LIMIT_MACROS
+#include <stdint.h>
 #include "ns3/assert.h"
 #include "ns3/log.h"
 #include "ns3/nstime.h"
@@ -29,6 +31,7 @@ 
 #include "ns3/simulator.h"
 #include "ns3/ipv4-route.h"
 #include "ns3/ipv6-route.h"
+#include "ns3/random-variable-stream.h"
 
 #include "tcp-l4-protocol.h"
 #include "tcp-header.h"
@@ -92,6 +95,7 @@ 
 {
   NS_LOG_FUNCTION_NOARGS ();
   NS_LOG_LOGIC ("Made a TcpL4Protocol " << this);
+  m_isnGenerator = CreateObject<UniformRandomVariable> ();
 }
 
 TcpL4Protocol::~TcpL4Protocol ()
@@ -99,6 +103,14 @@ 
   NS_LOG_FUNCTION (this);
 }
 
+int64_t
+TcpL4Protocol::AssignStreams (int64_t stream)
+{
+  NS_LOG_FUNCTION (this << stream);
+  m_isnGenerator->SetStream (stream);
+  return 1;
+}
+
 void
 TcpL4Protocol::SetNode (Ptr<Node> node)
 {
@@ -190,6 +202,7 @@ 
   socket->SetTcp (this);
   socket->SetRtt (rtt);
   socket->SetCongestionControlAlgorithm (algo);
+  socket->SetInitialSequence (m_isnGenerator->GetInteger (0, UINT32_MAX));
 
   m_sockets.push_back (socket);
   return socket;
@@ -697,6 +710,7 @@ 
       ++it;
     }
 
+  socket->SetInitialSequence (m_isnGenerator->GetInteger (0, UINT32_MAX));
   m_sockets.push_back (socket);
 }
 
--- a/src/internet/model/tcp-l4-protocol.h	Tue Feb 09 19:29:52 2016 +0300
+++ a/src/internet/model/tcp-l4-protocol.h	Mon Feb 15 09:45:55 2016 -0800
@@ -40,6 +40,7 @@ 
 class TcpSocketBase;
 class Ipv4EndPoint;
 class Ipv6EndPoint;
+class UniformRandomVariable;
 
 /**
  * \ingroup tcp
@@ -210,6 +211,16 @@ 
    */
   void DeAllocate (Ipv6EndPoint *endPoint);
 
+  /**
+   * Assign a fixed random variable stream number to the random variables
+   * used by this model.  Return the number of streams (possibly zero) that
+   * have been assigned.
+   *
+   * \param stream first stream index to use
+   * \return the number of stream indices assigned by this model
+   */
+  int64_t AssignStreams (int64_t stream);
+
   // From IpL4Protocol
   virtual enum IpL4Protocol::RxStatus Receive (Ptr<Packet> p,
                                                Ipv4Header const &incomingIpHeader,
@@ -281,6 +292,7 @@ 
   Ptr<Node> m_node;                //!< the node this stack is associated with
   Ipv4EndPointDemux *m_endPoints;  //!< A list of IPv4 end points.
   Ipv6EndPointDemux *m_endPoints6; //!< A list of IPv6 end points.
+  Ptr<UniformRandomVariable> m_isnGenerator; //! Generate TCP initial seq no
   TypeId m_rttTypeId;              //!< The RTT Estimator TypeId
   TypeId m_congestionTypeId;       //!< The socket TypeId
   std::vector<Ptr<TcpSocketBase> > m_sockets;      //!< list of sockets
--- a/src/internet/model/tcp-socket-base.cc	Tue Feb 09 19:29:52 2016 +0300
+++ a/src/internet/model/tcp-socket-base.cc	Mon Feb 15 09:45:55 2016 -0800
@@ -447,6 +447,14 @@ 
   m_tcp = tcp;
 }
 
+void
+TcpSocketBase::SetInitialSequence (uint32_t initialSequence)
+{
+  NS_LOG_FUNCTION (this << initialSequence);
+  NS_ABORT_MSG_IF (m_state > LISTEN, "cannot set initial sequence number on socket with state " << m_state);
+  m_nextTxSequence = initialSequence;
+}
+
 /* Set an RTT estimator with this socket */
 void
 TcpSocketBase::SetRtt (Ptr<RttEstimator> rtt)
--- a/src/internet/model/tcp-socket-base.h	Tue Feb 09 19:29:52 2016 +0300
+++ a/src/internet/model/tcp-socket-base.h	Mon Feb 15 09:45:55 2016 -0800
@@ -285,6 +285,15 @@ 
   virtual void SetTcp (Ptr<TcpL4Protocol> tcp);
 
   /**
+   * \brief Set TCP initial sequence number
+   * \param initialSequence the value to set
+   *
+   * This method will error exit the simulation if the socket state is
+   * not equal to CLOSED or LISTEN
+   */
+  virtual void SetInitialSequence (uint32_t initialSequence);
+
+  /**
    * \brief Set the associated RTT estimator.
    * \param rtt the RTT estimator
    */