src/devices/p2p -> src/devices/point-to-point
authorEmmanuelle Laprise <emmanuelle.laprise@bluekazoo.ca>
Fri, 27 Jul 2007 20:17:23 +0200
changeset 972 6946c8237a73
parent 971 7aba0cf0df19
child 973 2aea9e9f698c
src/devices/p2p -> src/devices/point-to-point
src/devices/p2p/p2p-channel.cc
src/devices/p2p/p2p-channel.h
src/devices/p2p/p2p-net-device.cc
src/devices/p2p/p2p-net-device.h
src/devices/p2p/p2p-topology.cc
src/devices/p2p/p2p-topology.h
src/devices/p2p/wscript
src/devices/point-to-point/p2p-channel.cc
src/devices/point-to-point/p2p-channel.h
src/devices/point-to-point/p2p-net-device.cc
src/devices/point-to-point/p2p-net-device.h
src/devices/point-to-point/p2p-topology.cc
src/devices/point-to-point/p2p-topology.h
src/devices/point-to-point/wscript
src/wscript
--- a/src/devices/p2p/p2p-channel.cc	Thu Jul 26 16:04:54 2007 +0200
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,142 +0,0 @@
-/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/*
- * Copyright (c) 2007 University of Washington
- * All rights reserved.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation;
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- *
- * Author: Craig Dowell <craigdo@ee.washington.edu>
- */
-
-#include "p2p-channel.h"
-#include "p2p-net-device.h"
-#include "ns3/packet.h"
-#include "ns3/simulator.h"
-#include "ns3/debug.h"
-
-NS_DEBUG_COMPONENT_DEFINE ("PointToPointChannel");
-
-namespace ns3 {
-
-//
-// By default, you get a channel with the name "PointToPoint Channel" that 
-// has an "infitely" fast transmission speed and zero delay.
-PointToPointChannel::PointToPointChannel()
-: 
-  Channel ("PointToPoint Channel"), 
-  m_bps (DataRate(0xffffffff)),
-  m_delay (Seconds(0)),
-  m_nDevices(0)
-{
-  NS_DEBUG("PointToPointChannel::PointToPointChannel ()");
-}
-
-PointToPointChannel::PointToPointChannel(
-  const DataRate& bps, 
-  const Time& delay)
-: 
-  Channel ("PointToPoint Channel"), 
-  m_bps (bps),
-  m_delay (delay),
-  m_nDevices(0)
-{
-  NS_DEBUG("PointToPointChannel::PointToPointChannel (" << Channel::GetName() 
-    << ", " << bps.GetBitRate() << ", " << delay << ")");
-}
-
-PointToPointChannel::PointToPointChannel(
-  const std::string& name,
-  const DataRate& bps, 
-  const Time& delay)
-: 
-  Channel (name),
-  m_bps (bps), 
-  m_delay (delay),
-  m_nDevices(0)
-{
-  NS_DEBUG("PointToPointChannel::PointToPointChannel (" << name << ", " << 
-    bps.GetBitRate() << ", " << delay << ")");
-}
-
-  void
-PointToPointChannel::Attach(Ptr<PointToPointNetDevice> device)
-{
-  NS_DEBUG("PointToPointChannel::Attach (" << device << ")");
-  NS_ASSERT(m_nDevices < N_DEVICES && "Only two devices permitted");
-  NS_ASSERT(device != 0);
-
-  m_link[m_nDevices++].m_src = device;
-//
-// If we have both devices connected to the channel, then finish introducing
-// the two halves and set the links to IDLE.
-//
-  if (m_nDevices == N_DEVICES)
-    {
-      m_link[0].m_dst = m_link[1].m_src;
-      m_link[1].m_dst = m_link[0].m_src;
-      m_link[0].m_state = IDLE;
-      m_link[1].m_state = IDLE;
-    }
-}
-
-bool PointToPointChannel::TransmitStart(Packet& p,
-                                        Ptr<PointToPointNetDevice> src,
-                                        const Time& txTime)
-{
-  NS_DEBUG ("PointToPointChannel::TransmitStart (" << &p << ", " << src << 
-            ")");
-  NS_DEBUG ("PointToPointChannel::TransmitStart (): UID is " << 
-            p.GetUid () << ")");
-
-  NS_ASSERT(m_link[0].m_state != INITIALIZING);
-  NS_ASSERT(m_link[1].m_state != INITIALIZING);
-
-  uint32_t wire = src == m_link[0].m_src ? 0 : 1;
-
-  // Here we schedule the packet receive event at the receiver,
-  // which simplifies this model quite a bit.  The channel just
-  // adds the propagation delay time
-  Simulator::Schedule (txTime + m_delay,
-                       &PointToPointNetDevice::Receive,
-                       m_link[wire].m_dst, p);
-  return true;
-}
-
-uint32_t 
-PointToPointChannel::GetNDevices (void) const
-{
-  return m_nDevices;
-}
-
-Ptr<NetDevice>
-PointToPointChannel::GetDevice (uint32_t i) const
-{
-  NS_ASSERT(i < 2);
-  return m_link[i].m_src;
-}
-
-const DataRate&
-PointToPointChannel::GetDataRate (void)
-{
-  return m_bps;
-}
-
-const Time&
-PointToPointChannel::GetDelay (void)
-{
-  return m_delay;
-}
-
-
-} // namespace ns3
--- a/src/devices/p2p/p2p-channel.h	Thu Jul 26 16:04:54 2007 +0200
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,127 +0,0 @@
-/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/*
- * Copyright (c) 2007 University of Washington
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation;
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- */
-
-#ifndef POINT_TO_POINT_CHANNEL_H
-#define POINT_TO_POINT_CHANNEL_H
-
-#include <list>
-#include "ns3/channel.h"
-#include "ns3/ptr.h"
-#include "ns3/packet.h"
-#include "ns3/nstime.h"
-#include "ns3/data-rate.h"
-
-namespace ns3 {
-
-class PointToPointNetDevice;
-
-/**
- * \brief Simple Point To Point Channel.
- *
- * This class represents a very simple point to point channel.  Think full
- * duplex RS-232 or RS-422 with null modem and no handshaking.  There is no
- * multi-drop capability on this channel -- there can be a maximum of two 
- * point-to-point net devices connected.  Once we start talking about multi-
- * drop, or CSMA, or some other sharing mechanism, things begin getting 
- * complicated quickly.  Rather than invent some ad-hoc mechanism, we just
- * Keep It Simple everywhere.
- *
- * When the channel is instaniated, the constructor takes parameters for
- * a single speed, in bits per second, and a speed-of-light delay time as a
- * Time object.  Both directions use the same speed and delay time.
- *
- * There are two "wires" in the channel.  The first device connected gets the
- * [0] wire to transmit on.  The second device gets the [1] wire.  There is a
- * state (IDLE, TRANSMITTING) associated with each wire.
- */
-class PointToPointChannel : public Channel {
-public:
-// Each point to point link has exactly two net devices
-  static const int N_DEVICES = 2;
-  /**
-   * \brief Create a PointToPointChannel
-   *
-   * By default, you get a channel with the name "PointToPoint Channel" that
-   * has an "infitely" fast transmission speed and zero delay.
-   */
-  PointToPointChannel ();
-  
-  /**
-   * \brief Create a PointToPointChannel
-   *
-   * \param bps The maximum bitrate of the channel
-   * \param delay Transmission delay through the channel
-   */  
-  PointToPointChannel (const DataRate& bps, const Time& delay);
-  
-  /**
-   * \brief Create a PointToPointChannel
-   *
-   * \param name the name of the channel for identification purposes
-   * \param bps The maximum bitrate of the channel
-   * \param delay Transmission delay through the channel
-   */
-  PointToPointChannel (const std::string& name,
-                 const DataRate& bps, const Time& delay);
-
-  /**
-   * \brief Attach a given netdevice to this channel
-   * \param device pointer to the netdevice to attach to the channel
-   */
-  void Attach (Ptr<PointToPointNetDevice> device);
-  bool TransmitStart (Packet& p, Ptr<PointToPointNetDevice> src,
-                      const Time& txTime);
-  // Below two not needed
-  //bool TransmitEnd (Packet &p, Ptr<PointToPointNetDevice> src);
-  //void PropagationCompleteEvent(Packet p, Ptr<PointToPointNetDevice> src);
-
-
-  virtual uint32_t GetNDevices (void) const;
-  virtual Ptr<NetDevice> GetDevice (uint32_t i) const;
-
-  virtual const DataRate& GetDataRate (void);
-  virtual const Time&     GetDelay (void);
-
-private:
-  DataRate      m_bps;
-  Time          m_delay;
-  int32_t       m_nDevices;
-
-  enum WireState
-    {
-      INITIALIZING,
-      IDLE,
-      TRANSMITTING,
-      PROPAGATING
-    };
-
-  class Link
-  {
-  public:
-    Link() : m_state (INITIALIZING), m_src (0), m_dst (0) {}
-    WireState              m_state;
-    Ptr<PointToPointNetDevice> m_src;
-    Ptr<PointToPointNetDevice> m_dst;
-  };
-    
-  Link    m_link[N_DEVICES];
-};
-
-} // namespace ns3
-
-#endif /* POINT_TO_POINT_CHANNEL_H */
--- a/src/devices/p2p/p2p-net-device.cc	Thu Jul 26 16:04:54 2007 +0200
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,221 +0,0 @@
-/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/*
- * Copyright (c) 2005,2006 INRIA
- * All rights reserved.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation;
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- *
- * Author:  Craig Dowell <craigdo@ee.washington.edu>
- * Revised: George Riley <riley@ece.gatech.edu>
- */
-
-#include <iostream>
-#include <cassert>
-#include "ns3/debug.h"
-#include "ns3/queue.h"
-#include "ns3/simulator.h"
-#include "ns3/composite-trace-resolver.h"
-#include "p2p-net-device.h"
-#include "p2p-channel.h"
-
-NS_DEBUG_COMPONENT_DEFINE ("PointToPointNetDevice");
-
-namespace ns3 {
-
-DataRateDefaultValue PointToPointNetDevice::g_defaultRate(
-           "PointToPointLinkDataRate", 
-           "The default data rate for point to point links",
-           DataRate ("10Mb/s"));
-
-  PointToPointNetDevice::PointToPointNetDevice (Ptr<Node> node,
-                                                const DataRate& rate) 
-: 
-  NetDevice(node, MacAddress (6)), 
-  m_txMachineState (READY),
-  m_bps (rate),
-  m_tInterframeGap (Seconds(0)),
-  m_channel (0), 
-  m_queue (0),
-  m_rxTrace ()
-{
-  NS_DEBUG ("PointToPointNetDevice::PointToPointNetDevice (" << node << ")");
-
-  // BUGBUG FIXME
-  //
-  // You _must_ support broadcast to get any sort of packet from the ARP layer.
-  EnableBroadcast (MacAddress ("ff:ff:ff:ff:ff:ff"));
-  EnableMulticast();
-  EnablePointToPoint();
-}
-
-PointToPointNetDevice::~PointToPointNetDevice()
-{
-  NS_DEBUG ("PointToPointNetDevice::~PointToPointNetDevice ()");
-  m_queue = 0;
-}
-
-void PointToPointNetDevice::DoDispose()
-{
-  m_channel = 0;
-  NetDevice::DoDispose ();
-}
-
-
-void PointToPointNetDevice::SetDataRate(const DataRate& bps)
-{
-  m_bps = bps;
-}
-
-void PointToPointNetDevice::SetInterframeGap(const Time& t)
-{
-  m_tInterframeGap = t;
-}
-
-bool PointToPointNetDevice::SendTo (Packet& p, const MacAddress& dest)
-{
-  NS_DEBUG ("PointToPointNetDevice::SendTo (" << &p << ", " << &dest << ")");
-  NS_DEBUG ("PointToPointNetDevice::SendTo (): UID is " << p.GetUid () << ")");
-
-  // GFR Comment. Why is this an assertion? Can't a link legitimately
-  // "go down" during the simulation?  Shouldn't we just wait for it
-  // to come back up?
-  NS_ASSERT (IsLinkUp ());
-
-//
-// This class simulates a point to point device.  In the case of a serial
-// link, this means that we're simulating something like a UART.
-//
-//
-// If there's a transmission in progress, we enque the packet for later
-// trnsmission; otherwise we send it now.
-    if (m_txMachineState == READY) 
-      {
-        return TransmitStart (p);
-      }
-    else
-      {
-        return m_queue->Enqueue(p);
-      }
-}
-
-  bool
-PointToPointNetDevice::TransmitStart (Packet &p)
-{
-  NS_DEBUG ("PointToPointNetDevice::TransmitStart (" << &p << ")");
-  NS_DEBUG (
-    "PointToPointNetDevice::TransmitStart (): UID is " << p.GetUid () << ")");
-//
-// This function is called to start the process of transmitting a packet.
-// We need to tell the channel that we've started wiggling the wire and
-// schedule an event that will be executed when the transmission is complete.
-//
-  NS_ASSERT_MSG(m_txMachineState == READY, "Must be READY to transmit");
-  m_txMachineState = BUSY;
-  Time txTime = Seconds (m_bps.CalculateTxTime(p.GetSize()));
-  Time txCompleteTime = txTime + m_tInterframeGap;
-
-  NS_DEBUG ("PointToPointNetDevice::TransmitStart (): " <<
-    "Schedule TransmitCompleteEvent in " << 
-    txCompleteTime.GetSeconds () << "sec");
-  // Schedule the tx complete event
-  Simulator::Schedule (txCompleteTime, 
-                       &PointToPointNetDevice::TransmitComplete, 
-                       this);
-  return m_channel->TransmitStart(p, this, txTime); 
-}
-
-void PointToPointNetDevice::TransmitComplete (void)
-{
-  NS_DEBUG ("PointToPointNetDevice::TransmitCompleteEvent ()");
-//
-// This function is called to finish the  process of transmitting a packet.
-// We need to tell the channel that we've stopped wiggling the wire and
-// get the next packet from the queue.  If the queue is empty, we are
-// done, otherwise transmit the next packet.
-//
-  NS_ASSERT_MSG(m_txMachineState == BUSY, "Must be BUSY if transmitting");
-  m_txMachineState = READY;
-  Packet p;
-  if (!m_queue->Dequeue(p)) return; // Nothing to do at this point
-  TransmitStart(p);
-}
-
-TraceResolver* PointToPointNetDevice::DoCreateTraceResolver (
-                                      TraceContext const &context)
-{
-  CompositeTraceResolver *resolver = new CompositeTraceResolver (context);
-  resolver->Add ("queue", 
-                 MakeCallback (&Queue::CreateTraceResolver, PeekPointer (m_queue)),
-                 PointToPointNetDevice::QUEUE);
-  resolver->Add ("rx",
-                 m_rxTrace,
-                 PointToPointNetDevice::RX);
-  return resolver;
-}
-
-bool PointToPointNetDevice::Attach (Ptr<PointToPointChannel> ch)
-{
-  NS_DEBUG ("PointToPointNetDevice::Attach (" << &ch << ")");
-
-  m_channel = ch;
-
-  m_channel->Attach(this);
-  m_bps = m_channel->GetDataRate ();
-  // GFR Comment.  Below is definitely wrong.  Interframe gap
-  // is unrelated to channel delay.
-  //m_tInterframeGap = m_channel->GetDelay ();
-
-  /* 
-   * For now, this device is up whenever a channel is attached to it.
-   * In fact, it should become up only when the second device
-   * is attached to the channel. So, there should be a way for
-   * a PointToPointChannel to notify both of its attached devices
-   * that the channel is 'complete', hence that the devices are
-   * up, hence that they can call NotifyLinkUp. 
-   */
-  NotifyLinkUp ();
-  return true;
-}
-
-void PointToPointNetDevice::AddQueue (Ptr<Queue> q)
-{
-  NS_DEBUG ("PointToPointNetDevice::AddQueue (" << q << ")");
-
-  m_queue = q;
-}
-
-void PointToPointNetDevice::Receive (Packet& p)
-{
-  NS_DEBUG ("PointToPointNetDevice::Receive (" << &p << ")");
-
-  m_rxTrace (p);
-  ForwardUp (p);
-}
-
-Ptr<Queue> PointToPointNetDevice::GetQueue(void) const 
-{ 
-    return m_queue;
-}
-
-Ptr<Channel> PointToPointNetDevice::DoGetChannel(void) const 
-{ 
-    return m_channel;
-}
-
-bool PointToPointNetDevice::DoNeedsArp (void) const
-{
-  return false;
-}
-
-} // namespace ns3
--- a/src/devices/p2p/p2p-net-device.h	Thu Jul 26 16:04:54 2007 +0200
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,296 +0,0 @@
-/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/*
- * Copyright (c) 2007 University of Washington
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation;
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- *
- * Author: Craig Dowell <craigdo@ee.washington.edu>
- */
-
-#ifndef POINT_TO_POINT_NET_DEVICE_H
-#define POINT_TO_POINT_NET_DEVICE_H
-
-#include <string.h>
-#include "ns3/mac-address.h"
-#include "ns3/node.h"
-#include "ns3/net-device.h"
-#include "ns3/callback.h"
-#include "ns3/packet.h"
-#include "ns3/callback-trace-source.h"
-#include "ns3/nstime.h"
-#include "ns3/data-rate.h"
-#include "ns3/default-value.h"
-#include "ns3/ptr.h"
-
-namespace ns3 {
-
-class Queue;
-class PointToPointChannel;
-
-/**
- * \class PointToPointNetDevice
- * \brief A Device for a Point to Point Network Link.
- *
- * Ns-3 takes a four-layer view of a protocol stack.  This is the same model
- * that TCP uses.  In this view, layers 5-7 of the OSI reference model are
- * grouped together into an application layer; layer four (transport / TCP) is
- * broken out; layer three (network / IP) is broken out; and layers 1-2 are
- * grouped together.  We call this grouping of layers one and two a NetDevice
- * and represent it as a class in the system.
- *
- * The NetDevice class is specialized according to the needs of the specific
- * kind of network link.  In this case, the link is a PointToPoint link.  The
- * PointToPoint link is a family of classes that includes this class, the
- * PointToPointNetDevice, a PointToPointChannel class that represents the 
- * actual medium across which bits are sent, a PointToPointIpv4Interface class
- * that provides the hook to tie a general purpose node to this specific
- * link, and finally, a PointToPointTopology object that is responsible for
- * putting all of the pieces together.
- *
- * This is the PointToPointNetDevice class that represents, essentially, the
- * PC card that is used to connect to the PointToPoint network.
- */
-class PointToPointNetDevice : public NetDevice {
-public:
-  /**
-   * Enumeration of the types of traces supported in the class.
-   *
-   */
-  enum TraceType {
-    QUEUE, /**< Trace queue events on the attached queue */
-    RX,    /**< Trace packet reception events (from the channel) */
-  };
-  /**
-   * Construct a PointToPointNetDevice
-   *
-   * This is the constructor for the PointToPointNetDevice.  It takes as a
-   * parameter the Node to which this device is connected.  Ownership of the
-   * Node pointer is not implied and the node must not be deleded.
-   *
-   * @see PointToPointTopology::AddPointToPointLink ()
-   * @param node the Node to which this device is connected.
-   */
-  PointToPointNetDevice (Ptr<Node> node,
-                         const DataRate& = g_defaultRate.GetValue());
-  /**
-   * Destroy a PointToPointNetDevice
-   *
-   * This is the destructor for the PointToPointNetDevice.
-   */
-  virtual ~PointToPointNetDevice();
-  /**
-   * Set the Data Rate used for transmission of packets.  The data rate is
-   * set in the Attach () method from the corresponding field in the channel
-   * to which the device is attached.  It can be overridden using this method.
-   *
-   * @see Attach ()
-   * @param bps the data rate at which this object operates
-   */
-  void SetDataRate(const DataRate& bps);
-  /**
-   * Set the inteframe gap used to separate packets.  The interframe gap
-   * defines the minimum space required between packets sent by this device.
-   * It is usually set in the Attach () method based on the speed of light
-   * delay of the channel to which the device is attached.  It can be 
-   * overridden using this method if desired.
-   *
-   * @see Attach ()
-   * @param t the interframe gap time
-   */
-  void SetInterframeGap(const Time& t);
-  /**
-   * Attach the device to a channel.
-   *
-   * The PointToPointTopology object creates a PointToPointChannel and two
-   * PointtoPointNetDevices.  In order to introduce these components to each
-   * other, the topology object calls Attach () on each PointToPointNetDevice.
-   * Inside this method, the Net Device calls out to the PointToPointChannel
-   * to introduce itself.
-   *
-   * @see PointToPointTopology::AddPointToPointLink ()
-   * @see SetDataRate ()
-   * @see SetInterframeGap ()
-   * @param ch a pointer to the channel to which this object is being attached.
-   */
-  bool Attach(Ptr<PointToPointChannel> ch);
-  /**
-   * Attach a queue to the PointToPointNetDevice.
-   *
-   * The PointToPointNetDevice "owns" a queue.  This queue is created by the
-   * PointToPointTopology object and implements a queueing method such as
-   * DropTail or RED.  The PointToPointNetDevice assumes ownership of this
-   * queue and must delete it when the device is destroyed.
-   *
-   * @see PointToPointTopology::AddPointToPointLink ()
-   * @see Queue
-   * @see DropTailQueue
-   * @param queue a pointer to the queue for which object is assuming
-   *        ownership.
-   */
-  void AddQueue(Ptr<Queue> queue);
-  /**
-   * Receive a packet from a connected PointToPointChannel.
-   *
-   * The PointToPointNetDevice receives packets from its connected channel
-   * and forwards them up the protocol stack.  This is the public method
-   * used by the channel to indicate that the last bit of a packet has 
-   * arrived at the device.
-   *
-   * @see PointToPointChannel
-   * @param p a reference to the received packet
-   */
-  void Receive (Packet& p);
-protected:
-  virtual void DoDispose (void);
-  /**
-   * Get a copy of the attached Queue.
-   *
-   * This method is provided for any derived class that may need to get
-   * direct access to the underlying queue.
-   *
-   * @see PointToPointTopology
-   * @returns a pointer to the queue.
-   */
-  Ptr<Queue> GetQueue(void) const; 
-  /**
-   * Get a copy of the attached Channel
-   *
-   * This method is provided for any derived class that may need to get
-   * direct access to the connected channel
-   *
-   * @see PointToPointChannel
-   * @returns a pointer to the channel
-   */
-  virtual Ptr<Channel> DoGetChannel(void) const;
-  /**
-   * Set a new default data rate
-   * @param Data rate to set for new default
-   */
-  static void SetDefaultRate(const DataRate&);
-
-  /** 
-   * Get the current default rate.
-   * @returns a const reference to current default
-   */
-
-  static const DataRate& GetDefaultRate();
-
-private:
-  // unimplemented methods to make it impossible
-  // to copy these objects.
-  PointToPointNetDevice (const PointToPointNetDevice& nd);
-  PointToPointNetDevice& operator = (const PointToPointNetDevice&o);
-  
-  /**
-   * Send a Packet Down the Wire.
-   *
-   * The SendTo method is defined as the standard way that the level three
-   * protocol uses to tell a NetDevice to send a packet.  SendTo is declared
-   * as abstract in the NetDevice class and we declare it here.
-   *
-   * @see NetDevice
-   * @param p a reference to the packet to send
-   * @param dest a reference to the MacAddress of the destination device
-   * @returns true if success, false on failure
-   */
-  virtual bool SendTo (Packet& p, const MacAddress& dest);
-  /**
-   * Start Sending a Packet Down the Wire.
-   *
-   * The TransmitStart method is the method that is used internally in the
-   * PointToPointNetDevice to begin the process of sending a packet out on
-   * the channel.  The corresponding method is called on the channel to let
-   * it know that the physical device this class represents has virually
-   * started sending signals.  An event is scheduled for the time at which
-   * the bits have been completely transmitted.
-   *
-   * @see PointToPointChannel::TransmitStart ()
-   * @see TransmitCompleteEvent ()
-   * @param p a reference to the packet to send
-   * @returns true if success, false on failure
-   */
-  bool TransmitStart (Packet &p);
-  /**
-   * Stop Sending a Packet Down the Wire and Begin the Interframe Gap.
-   *
-   * The TransmitComplete method is used internally to finish the process
-   * of sending a packet out on the channel.
-   *
-   */
-  void TransmitComplete(void);
-  /**
-   * Create a Trace Resolver for events in the net device.
-   *
-   * @see class TraceResolver
-   */
-  virtual TraceResolver* DoCreateTraceResolver (TraceContext const &context);
-  virtual bool DoNeedsArp (void) const;
-  /**
-   * Enumeration of the states of the transmit machine of the net device.
-   */
-  enum TxMachineState
-    {
-      READY, /**< The transmitter is ready to begin transmission of a packet */
-      BUSY   /**< The transmitter is busy transmitting a packet */
-    };
-  /**
-   * The state of the Net Device transmit state machine.
-   * @see TxMachineState
-   */
-  TxMachineState m_txMachineState;
-  /**
-   * The data rate that the Net Device uses to simulate packet transmission
-   * timing.
-   * @see class DataRate
-   */
-  DataRate       m_bps;
-  /**
-   * The interframe gap that the Net Device uses to throttle packet
-   * transmission
-   * @see class Time
-   */
-  Time           m_tInterframeGap;
-  /**
-   * The PointToPointChannel to which this PointToPointNetDevice has been
-   * attached.
-   * @see class PointToPointChannel
-   */
-  Ptr<PointToPointChannel> m_channel;
-  /**
-   * The Queue which this PointToPointNetDevice uses as a packet source.
-   * Management of this Queue has been delegated to the PointToPointNetDevice
-   * and it has the responsibility for deletion.
-   * @see class Queue
-   * @see class DropTailQueue
-   */
-  Ptr<Queue> m_queue;
-  /**
-   * The trace source for the packet reception events that the device can
-   * fire.
-   *
-   * @see class CallBackTraceSource
-   * @see class TraceResolver
-   */
-  CallbackTraceSource<Packet &> m_rxTrace;
-  /** 
-   * Default data rate.  Used for all newly created p2p net devices
-   */
-   static DataRateDefaultValue g_defaultRate;
-
-};
-
-}; // namespace ns3
-
-#endif // POINT_TO_POINT_NET_DEVICE_H
-
--- a/src/devices/p2p/p2p-topology.cc	Thu Jul 26 16:04:54 2007 +0200
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,172 +0,0 @@
-/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-//
-// Copyright (c) 2006 Georgia Tech Research Corporation
-//
-// This program is free software; you can redistribute it and/or modify
-// it under the terms of the GNU General Public License version 2 as
-// published by the Free Software Foundation;
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with this program; if not, write to the Free Software
-// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-//
-// Author: George F. Riley<riley@ece.gatech.edu>
-//
-
-//
-// Topology helper for ns3.
-// George F. Riley, Georgia Tech, Spring 2007
-
-#include <algorithm>
-#include "ns3/assert.h"
-#include "ns3/debug.h"
-#include "ns3/fatal-error.h"
-#include "ns3/nstime.h"
-#include "ns3/internet-node.h"
-#include "ns3/ipv4-address.h"
-#include "ns3/ipv4.h"
-#include "ns3/queue.h"
-
-#include "p2p-channel.h"
-#include "p2p-net-device.h"
-#include "p2p-topology.h"
-
-namespace ns3 {
-
-Ptr<PointToPointChannel>
-PointToPointTopology::AddPointToPointLink(
-  Ptr<Node> n1,
-  Ptr<Node> n2,
-  const DataRate& bps,
-  const Time& delay)
-{
-  Ptr<PointToPointChannel> channel = Create<PointToPointChannel> (bps, delay);
-
-  Ptr<PointToPointNetDevice> net1 = Create<PointToPointNetDevice> (n1);
-
-  Ptr<Queue> q = Queue::CreateDefault ();
-  net1->AddQueue(q);
-  net1->Attach (channel);
-  
-  Ptr<PointToPointNetDevice> net2 = Create<PointToPointNetDevice> (n2);
-
-  q = Queue::CreateDefault ();
-  net2->AddQueue(q);
-  net2->Attach (channel);
-
-  return channel;
-}
-
-void
-PointToPointTopology::AddIpv4Addresses(
-  Ptr<const PointToPointChannel> chan,
-  Ptr<Node> n1, const Ipv4Address& addr1,
-  Ptr<Node> n2, const Ipv4Address& addr2)
-{
-
-  // Duplex link is assumed to be subnetted as a /30
-  // May run this unnumbered in the future?
-  Ipv4Mask netmask("255.255.255.252");
-  NS_ASSERT (netmask.IsMatch(addr1,addr2));
-
-  // The PointToPoint channel is used to find the relevant NetDevices
-  NS_ASSERT (chan->GetNDevices () == 2);
-  Ptr<NetDevice> nd1 = chan->GetDevice (0);
-  Ptr<NetDevice> nd2 = chan->GetDevice (1);
-  // Make sure that nd1 belongs to n1 and nd2 to n2
-  if ( (nd1->GetNode ()->GetId () == n2->GetId () ) && 
-       (nd2->GetNode ()->GetId () == n1->GetId () ) )
-    {
-      std::swap(nd1, nd2);
-    }
-  NS_ASSERT (nd1->GetNode ()->GetId () == n1->GetId ());
-  NS_ASSERT (nd2->GetNode ()->GetId () == n2->GetId ());
-  
-  Ptr<Ipv4> ip1 = n1->QueryInterface<Ipv4> (Ipv4::iid);
-  uint32_t index1 = ip1->AddInterface (nd1);
-
-  ip1->SetAddress (index1, addr1);
-  ip1->SetNetworkMask (index1, netmask);
-  ip1->SetUp (index1);
-
-  Ptr<Ipv4> ip2 = n2->QueryInterface<Ipv4> (Ipv4::iid);
-  uint32_t index2 = ip2->AddInterface (nd2);
-
-  ip2->SetAddress (index2, addr2);
-  ip2->SetNetworkMask (index2, netmask);
-  ip2->SetUp (index2);
-  
-}
-
-void
-PointToPointTopology::AddIpv4Routes (
-  Ptr<Node> n1, Ptr<Node> n2, Ptr<const PointToPointChannel> chan)
-{ 
-  // The PointToPoint channel is used to find the relevant NetDevices
-  NS_ASSERT (chan->GetNDevices () == 2);
-  Ptr<NetDevice> nd1 = chan->GetDevice (0);
-  Ptr<NetDevice> nd2 = chan->GetDevice (1);
-
-  // Assert that n1 is the Node owning one of the two NetDevices
-  // and make sure that nd1 corresponds to it
-  if (nd1->GetNode ()->GetId () == n1->GetId ())
-    {
-      ; // Do nothing
-    }
-  else if (nd2->GetNode ()->GetId () == n1->GetId ())
-    {
-      std::swap(nd1, nd2);
-    }
-  else
-    {
-      NS_FATAL_ERROR("P2PTopo: Node does not contain an interface on Channel");
-    }
-
-   // Assert that n2 is the Node owning one of the two NetDevices
-   // and make sure that nd2 corresponds to it
-  if (nd2->GetNode ()->GetId () != n2->GetId ())
-    {
-      NS_FATAL_ERROR("P2PTopo: Node does not contain an interface on Channel");
-    }
-
-  // Assert that both are Ipv4 nodes
-  Ptr<Ipv4> ip1 = nd1->GetNode ()->QueryInterface<Ipv4> (Ipv4::iid);
-  Ptr<Ipv4> ip2 = nd2->GetNode ()->QueryInterface<Ipv4> (Ipv4::iid);
-  NS_ASSERT(ip1 != 0 && ip2 != 0);
-
-  // Get interface indexes for both nodes corresponding to the right channel
-  uint32_t index1 = 0;
-  bool found = false;
-  for (uint32_t i = 0; i < ip1->GetNInterfaces (); i++)
-    {
-      if (ip1 ->GetNetDevice (i) == nd1)
-        {
-          index1 = i;
-          found = true;
-        }
-    }
-  NS_ASSERT(found);
-
-  uint32_t index2 = 0;
-  found = false;
-  for (uint32_t i = 0; i < ip2->GetNInterfaces (); i++)
-    {
-      if (ip2 ->GetNetDevice (i) == nd2)
-        {
-          index2 = i;
-          found = true;
-        }
-    }
-  NS_ASSERT(found);
-
-  ip1->AddHostRouteTo (ip2-> GetAddress (index2), index1);
-  ip2->AddHostRouteTo (ip1-> GetAddress (index1), index2); 
-}
-
-} // namespace ns3
- 
--- a/src/devices/p2p/p2p-topology.h	Thu Jul 26 16:04:54 2007 +0200
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,87 +0,0 @@
-/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-//
-// Copyright (c) 2006 Georgia Tech Research Corporation
-//
-// This program is free software; you can redistribute it and/or modify
-// it under the terms of the GNU General Public License version 2 as
-// published by the Free Software Foundation;
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with this program; if not, write to the Free Software
-// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-//
-// Author: George F. Riley<riley@ece.gatech.edu>
-//
-// Topology helper for ns3.
-// George F. Riley, Georgia Tech, Spring 2007
-#ifndef __POINT_TO_POINT_TOPOLOGY_H__
-#define __POINT_TO_POINT_TOPOLOGY_H__
-
-#include "ns3/ptr.h"
-
-// The topology class consists of only static methods thar are used to
-// create the topology and data flows for an ns3 simulation
-
-namespace ns3 {
-
-class PointToPointChannel;
-class Node;
-class IPAddr;
-class DataRate;
-class Queue;
-
-/**
- * \brief A helper class to create Topologies based on the 
- * ns3::PointToPointNetDevice and  ns3::PointToPointChannel objects.
- */
-class PointToPointTopology {
-public:
-  /** 
-   * \param n1 Node
-   * \param n2 Node
-   * \param dataRate Maximum transmission link rate 
-   * \param delay one-way propagation delay 
-   * \return Pointer to the underlying PointToPointChannel
-   * 
-   * Add a full-duplex point-to-point link between two nodes
-   * and attach PointToPointNetDevices to the resulting
-   * PointToPointChannel.  
-   */
-  static Ptr<PointToPointChannel> AddPointToPointLink(
-    Ptr<Node> n1, Ptr<Node> n2, const DataRate& dataRate, const Time& delay);
-
-  /** 
-   * \param chan PointToPointChannel to use
-   * \param n1 Node
-   * \param addr1 Ipv4 Address for n1
-   * \param n2 Node
-   * \param addr2 Ipv4 Address for n2
-   * 
-   * Add Ipv4Addresses to the Ipv4 interfaces associated with the 
-   * two PointToPointNetDevices on the provided PointToPointChannel
-   */
-  static void AddIpv4Addresses(
-    Ptr<const PointToPointChannel> chan,
-    Ptr<Node> n1, const Ipv4Address& addr1,
-    Ptr<Node> n2, const Ipv4Address& addr2);
-
-  /**
-   * \param channel PointToPointChannel to use
-   * \param n1 Node
-   * \param n2 Node
-   * 
-   * For the given PointToPointChannel, for each Node, add an 
-   * IPv4 host route to the IPv4 address of the peer node.  
-   */
-  static void AddIpv4Routes (Ptr<Node> n1, Ptr<Node> n2, Ptr<const PointToPointChannel> channel);
-};
-
-} // namespace ns3
-
-#endif
-
--- a/src/devices/p2p/wscript	Thu Jul 26 16:04:54 2007 +0200
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,22 +0,0 @@
-## -*- Mode: python; py-indent-offset: 4; indent-tabs-mode: nil; coding: utf-8; -*-
-
-
-def build(bld):
-    p2p = bld.create_obj('cpp', 'shlib')
-    p2p.name = 'ns3-p2p'
-    p2p.target = p2p.name
-    p2p.uselib_local = ['ns3-node']
-    p2p.source = [
-        'p2p-net-device.cc',
-        'p2p-channel.cc',
-        'p2p-topology.cc',
-        ]
-    p2p.includes = '.'
-
-    headers = bld.create_obj('ns3header')
-    headers.source = [
-        'p2p-net-device.h',
-        'p2p-channel.h',
-        'p2p-topology.h',
-        ]
-
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/devices/point-to-point/p2p-channel.cc	Fri Jul 27 20:17:23 2007 +0200
@@ -0,0 +1,142 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2007 University of Washington
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Author: Craig Dowell <craigdo@ee.washington.edu>
+ */
+
+#include "p2p-channel.h"
+#include "p2p-net-device.h"
+#include "ns3/packet.h"
+#include "ns3/simulator.h"
+#include "ns3/debug.h"
+
+NS_DEBUG_COMPONENT_DEFINE ("PointToPointChannel");
+
+namespace ns3 {
+
+//
+// By default, you get a channel with the name "PointToPoint Channel" that 
+// has an "infitely" fast transmission speed and zero delay.
+PointToPointChannel::PointToPointChannel()
+: 
+  Channel ("PointToPoint Channel"), 
+  m_bps (DataRate(0xffffffff)),
+  m_delay (Seconds(0)),
+  m_nDevices(0)
+{
+  NS_DEBUG("PointToPointChannel::PointToPointChannel ()");
+}
+
+PointToPointChannel::PointToPointChannel(
+  const DataRate& bps, 
+  const Time& delay)
+: 
+  Channel ("PointToPoint Channel"), 
+  m_bps (bps),
+  m_delay (delay),
+  m_nDevices(0)
+{
+  NS_DEBUG("PointToPointChannel::PointToPointChannel (" << Channel::GetName() 
+    << ", " << bps.GetBitRate() << ", " << delay << ")");
+}
+
+PointToPointChannel::PointToPointChannel(
+  const std::string& name,
+  const DataRate& bps, 
+  const Time& delay)
+: 
+  Channel (name),
+  m_bps (bps), 
+  m_delay (delay),
+  m_nDevices(0)
+{
+  NS_DEBUG("PointToPointChannel::PointToPointChannel (" << name << ", " << 
+    bps.GetBitRate() << ", " << delay << ")");
+}
+
+  void
+PointToPointChannel::Attach(Ptr<PointToPointNetDevice> device)
+{
+  NS_DEBUG("PointToPointChannel::Attach (" << device << ")");
+  NS_ASSERT(m_nDevices < N_DEVICES && "Only two devices permitted");
+  NS_ASSERT(device != 0);
+
+  m_link[m_nDevices++].m_src = device;
+//
+// If we have both devices connected to the channel, then finish introducing
+// the two halves and set the links to IDLE.
+//
+  if (m_nDevices == N_DEVICES)
+    {
+      m_link[0].m_dst = m_link[1].m_src;
+      m_link[1].m_dst = m_link[0].m_src;
+      m_link[0].m_state = IDLE;
+      m_link[1].m_state = IDLE;
+    }
+}
+
+bool PointToPointChannel::TransmitStart(Packet& p,
+                                        Ptr<PointToPointNetDevice> src,
+                                        const Time& txTime)
+{
+  NS_DEBUG ("PointToPointChannel::TransmitStart (" << &p << ", " << src << 
+            ")");
+  NS_DEBUG ("PointToPointChannel::TransmitStart (): UID is " << 
+            p.GetUid () << ")");
+
+  NS_ASSERT(m_link[0].m_state != INITIALIZING);
+  NS_ASSERT(m_link[1].m_state != INITIALIZING);
+
+  uint32_t wire = src == m_link[0].m_src ? 0 : 1;
+
+  // Here we schedule the packet receive event at the receiver,
+  // which simplifies this model quite a bit.  The channel just
+  // adds the propagation delay time
+  Simulator::Schedule (txTime + m_delay,
+                       &PointToPointNetDevice::Receive,
+                       m_link[wire].m_dst, p);
+  return true;
+}
+
+uint32_t 
+PointToPointChannel::GetNDevices (void) const
+{
+  return m_nDevices;
+}
+
+Ptr<NetDevice>
+PointToPointChannel::GetDevice (uint32_t i) const
+{
+  NS_ASSERT(i < 2);
+  return m_link[i].m_src;
+}
+
+const DataRate&
+PointToPointChannel::GetDataRate (void)
+{
+  return m_bps;
+}
+
+const Time&
+PointToPointChannel::GetDelay (void)
+{
+  return m_delay;
+}
+
+
+} // namespace ns3
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/devices/point-to-point/p2p-channel.h	Fri Jul 27 20:17:23 2007 +0200
@@ -0,0 +1,127 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2007 University of Washington
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef POINT_TO_POINT_CHANNEL_H
+#define POINT_TO_POINT_CHANNEL_H
+
+#include <list>
+#include "ns3/channel.h"
+#include "ns3/ptr.h"
+#include "ns3/packet.h"
+#include "ns3/nstime.h"
+#include "ns3/data-rate.h"
+
+namespace ns3 {
+
+class PointToPointNetDevice;
+
+/**
+ * \brief Simple Point To Point Channel.
+ *
+ * This class represents a very simple point to point channel.  Think full
+ * duplex RS-232 or RS-422 with null modem and no handshaking.  There is no
+ * multi-drop capability on this channel -- there can be a maximum of two 
+ * point-to-point net devices connected.  Once we start talking about multi-
+ * drop, or CSMA, or some other sharing mechanism, things begin getting 
+ * complicated quickly.  Rather than invent some ad-hoc mechanism, we just
+ * Keep It Simple everywhere.
+ *
+ * When the channel is instaniated, the constructor takes parameters for
+ * a single speed, in bits per second, and a speed-of-light delay time as a
+ * Time object.  Both directions use the same speed and delay time.
+ *
+ * There are two "wires" in the channel.  The first device connected gets the
+ * [0] wire to transmit on.  The second device gets the [1] wire.  There is a
+ * state (IDLE, TRANSMITTING) associated with each wire.
+ */
+class PointToPointChannel : public Channel {
+public:
+// Each point to point link has exactly two net devices
+  static const int N_DEVICES = 2;
+  /**
+   * \brief Create a PointToPointChannel
+   *
+   * By default, you get a channel with the name "PointToPoint Channel" that
+   * has an "infitely" fast transmission speed and zero delay.
+   */
+  PointToPointChannel ();
+  
+  /**
+   * \brief Create a PointToPointChannel
+   *
+   * \param bps The maximum bitrate of the channel
+   * \param delay Transmission delay through the channel
+   */  
+  PointToPointChannel (const DataRate& bps, const Time& delay);
+  
+  /**
+   * \brief Create a PointToPointChannel
+   *
+   * \param name the name of the channel for identification purposes
+   * \param bps The maximum bitrate of the channel
+   * \param delay Transmission delay through the channel
+   */
+  PointToPointChannel (const std::string& name,
+                 const DataRate& bps, const Time& delay);
+
+  /**
+   * \brief Attach a given netdevice to this channel
+   * \param device pointer to the netdevice to attach to the channel
+   */
+  void Attach (Ptr<PointToPointNetDevice> device);
+  bool TransmitStart (Packet& p, Ptr<PointToPointNetDevice> src,
+                      const Time& txTime);
+  // Below two not needed
+  //bool TransmitEnd (Packet &p, Ptr<PointToPointNetDevice> src);
+  //void PropagationCompleteEvent(Packet p, Ptr<PointToPointNetDevice> src);
+
+
+  virtual uint32_t GetNDevices (void) const;
+  virtual Ptr<NetDevice> GetDevice (uint32_t i) const;
+
+  virtual const DataRate& GetDataRate (void);
+  virtual const Time&     GetDelay (void);
+
+private:
+  DataRate      m_bps;
+  Time          m_delay;
+  int32_t       m_nDevices;
+
+  enum WireState
+    {
+      INITIALIZING,
+      IDLE,
+      TRANSMITTING,
+      PROPAGATING
+    };
+
+  class Link
+  {
+  public:
+    Link() : m_state (INITIALIZING), m_src (0), m_dst (0) {}
+    WireState              m_state;
+    Ptr<PointToPointNetDevice> m_src;
+    Ptr<PointToPointNetDevice> m_dst;
+  };
+    
+  Link    m_link[N_DEVICES];
+};
+
+} // namespace ns3
+
+#endif /* POINT_TO_POINT_CHANNEL_H */
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/devices/point-to-point/p2p-net-device.cc	Fri Jul 27 20:17:23 2007 +0200
@@ -0,0 +1,221 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2005,2006 INRIA
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Author:  Craig Dowell <craigdo@ee.washington.edu>
+ * Revised: George Riley <riley@ece.gatech.edu>
+ */
+
+#include <iostream>
+#include <cassert>
+#include "ns3/debug.h"
+#include "ns3/queue.h"
+#include "ns3/simulator.h"
+#include "ns3/composite-trace-resolver.h"
+#include "p2p-net-device.h"
+#include "p2p-channel.h"
+
+NS_DEBUG_COMPONENT_DEFINE ("PointToPointNetDevice");
+
+namespace ns3 {
+
+DataRateDefaultValue PointToPointNetDevice::g_defaultRate(
+           "PointToPointLinkDataRate", 
+           "The default data rate for point to point links",
+           DataRate ("10Mb/s"));
+
+  PointToPointNetDevice::PointToPointNetDevice (Ptr<Node> node,
+                                                const DataRate& rate) 
+: 
+  NetDevice(node, MacAddress (6)), 
+  m_txMachineState (READY),
+  m_bps (rate),
+  m_tInterframeGap (Seconds(0)),
+  m_channel (0), 
+  m_queue (0),
+  m_rxTrace ()
+{
+  NS_DEBUG ("PointToPointNetDevice::PointToPointNetDevice (" << node << ")");
+
+  // BUGBUG FIXME
+  //
+  // You _must_ support broadcast to get any sort of packet from the ARP layer.
+  EnableBroadcast (MacAddress ("ff:ff:ff:ff:ff:ff"));
+  EnableMulticast();
+  EnablePointToPoint();
+}
+
+PointToPointNetDevice::~PointToPointNetDevice()
+{
+  NS_DEBUG ("PointToPointNetDevice::~PointToPointNetDevice ()");
+  m_queue = 0;
+}
+
+void PointToPointNetDevice::DoDispose()
+{
+  m_channel = 0;
+  NetDevice::DoDispose ();
+}
+
+
+void PointToPointNetDevice::SetDataRate(const DataRate& bps)
+{
+  m_bps = bps;
+}
+
+void PointToPointNetDevice::SetInterframeGap(const Time& t)
+{
+  m_tInterframeGap = t;
+}
+
+bool PointToPointNetDevice::SendTo (Packet& p, const MacAddress& dest)
+{
+  NS_DEBUG ("PointToPointNetDevice::SendTo (" << &p << ", " << &dest << ")");
+  NS_DEBUG ("PointToPointNetDevice::SendTo (): UID is " << p.GetUid () << ")");
+
+  // GFR Comment. Why is this an assertion? Can't a link legitimately
+  // "go down" during the simulation?  Shouldn't we just wait for it
+  // to come back up?
+  NS_ASSERT (IsLinkUp ());
+
+//
+// This class simulates a point to point device.  In the case of a serial
+// link, this means that we're simulating something like a UART.
+//
+//
+// If there's a transmission in progress, we enque the packet for later
+// trnsmission; otherwise we send it now.
+    if (m_txMachineState == READY) 
+      {
+        return TransmitStart (p);
+      }
+    else
+      {
+        return m_queue->Enqueue(p);
+      }
+}
+
+  bool
+PointToPointNetDevice::TransmitStart (Packet &p)
+{
+  NS_DEBUG ("PointToPointNetDevice::TransmitStart (" << &p << ")");
+  NS_DEBUG (
+    "PointToPointNetDevice::TransmitStart (): UID is " << p.GetUid () << ")");
+//
+// This function is called to start the process of transmitting a packet.
+// We need to tell the channel that we've started wiggling the wire and
+// schedule an event that will be executed when the transmission is complete.
+//
+  NS_ASSERT_MSG(m_txMachineState == READY, "Must be READY to transmit");
+  m_txMachineState = BUSY;
+  Time txTime = Seconds (m_bps.CalculateTxTime(p.GetSize()));
+  Time txCompleteTime = txTime + m_tInterframeGap;
+
+  NS_DEBUG ("PointToPointNetDevice::TransmitStart (): " <<
+    "Schedule TransmitCompleteEvent in " << 
+    txCompleteTime.GetSeconds () << "sec");
+  // Schedule the tx complete event
+  Simulator::Schedule (txCompleteTime, 
+                       &PointToPointNetDevice::TransmitComplete, 
+                       this);
+  return m_channel->TransmitStart(p, this, txTime); 
+}
+
+void PointToPointNetDevice::TransmitComplete (void)
+{
+  NS_DEBUG ("PointToPointNetDevice::TransmitCompleteEvent ()");
+//
+// This function is called to finish the  process of transmitting a packet.
+// We need to tell the channel that we've stopped wiggling the wire and
+// get the next packet from the queue.  If the queue is empty, we are
+// done, otherwise transmit the next packet.
+//
+  NS_ASSERT_MSG(m_txMachineState == BUSY, "Must be BUSY if transmitting");
+  m_txMachineState = READY;
+  Packet p;
+  if (!m_queue->Dequeue(p)) return; // Nothing to do at this point
+  TransmitStart(p);
+}
+
+TraceResolver* PointToPointNetDevice::DoCreateTraceResolver (
+                                      TraceContext const &context)
+{
+  CompositeTraceResolver *resolver = new CompositeTraceResolver (context);
+  resolver->Add ("queue", 
+                 MakeCallback (&Queue::CreateTraceResolver, PeekPointer (m_queue)),
+                 PointToPointNetDevice::QUEUE);
+  resolver->Add ("rx",
+                 m_rxTrace,
+                 PointToPointNetDevice::RX);
+  return resolver;
+}
+
+bool PointToPointNetDevice::Attach (Ptr<PointToPointChannel> ch)
+{
+  NS_DEBUG ("PointToPointNetDevice::Attach (" << &ch << ")");
+
+  m_channel = ch;
+
+  m_channel->Attach(this);
+  m_bps = m_channel->GetDataRate ();
+  // GFR Comment.  Below is definitely wrong.  Interframe gap
+  // is unrelated to channel delay.
+  //m_tInterframeGap = m_channel->GetDelay ();
+
+  /* 
+   * For now, this device is up whenever a channel is attached to it.
+   * In fact, it should become up only when the second device
+   * is attached to the channel. So, there should be a way for
+   * a PointToPointChannel to notify both of its attached devices
+   * that the channel is 'complete', hence that the devices are
+   * up, hence that they can call NotifyLinkUp. 
+   */
+  NotifyLinkUp ();
+  return true;
+}
+
+void PointToPointNetDevice::AddQueue (Ptr<Queue> q)
+{
+  NS_DEBUG ("PointToPointNetDevice::AddQueue (" << q << ")");
+
+  m_queue = q;
+}
+
+void PointToPointNetDevice::Receive (Packet& p)
+{
+  NS_DEBUG ("PointToPointNetDevice::Receive (" << &p << ")");
+
+  m_rxTrace (p);
+  ForwardUp (p);
+}
+
+Ptr<Queue> PointToPointNetDevice::GetQueue(void) const 
+{ 
+    return m_queue;
+}
+
+Ptr<Channel> PointToPointNetDevice::DoGetChannel(void) const 
+{ 
+    return m_channel;
+}
+
+bool PointToPointNetDevice::DoNeedsArp (void) const
+{
+  return false;
+}
+
+} // namespace ns3
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/devices/point-to-point/p2p-net-device.h	Fri Jul 27 20:17:23 2007 +0200
@@ -0,0 +1,296 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2007 University of Washington
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Author: Craig Dowell <craigdo@ee.washington.edu>
+ */
+
+#ifndef POINT_TO_POINT_NET_DEVICE_H
+#define POINT_TO_POINT_NET_DEVICE_H
+
+#include <string.h>
+#include "ns3/mac-address.h"
+#include "ns3/node.h"
+#include "ns3/net-device.h"
+#include "ns3/callback.h"
+#include "ns3/packet.h"
+#include "ns3/callback-trace-source.h"
+#include "ns3/nstime.h"
+#include "ns3/data-rate.h"
+#include "ns3/default-value.h"
+#include "ns3/ptr.h"
+
+namespace ns3 {
+
+class Queue;
+class PointToPointChannel;
+
+/**
+ * \class PointToPointNetDevice
+ * \brief A Device for a Point to Point Network Link.
+ *
+ * Ns-3 takes a four-layer view of a protocol stack.  This is the same model
+ * that TCP uses.  In this view, layers 5-7 of the OSI reference model are
+ * grouped together into an application layer; layer four (transport / TCP) is
+ * broken out; layer three (network / IP) is broken out; and layers 1-2 are
+ * grouped together.  We call this grouping of layers one and two a NetDevice
+ * and represent it as a class in the system.
+ *
+ * The NetDevice class is specialized according to the needs of the specific
+ * kind of network link.  In this case, the link is a PointToPoint link.  The
+ * PointToPoint link is a family of classes that includes this class, the
+ * PointToPointNetDevice, a PointToPointChannel class that represents the 
+ * actual medium across which bits are sent, a PointToPointIpv4Interface class
+ * that provides the hook to tie a general purpose node to this specific
+ * link, and finally, a PointToPointTopology object that is responsible for
+ * putting all of the pieces together.
+ *
+ * This is the PointToPointNetDevice class that represents, essentially, the
+ * PC card that is used to connect to the PointToPoint network.
+ */
+class PointToPointNetDevice : public NetDevice {
+public:
+  /**
+   * Enumeration of the types of traces supported in the class.
+   *
+   */
+  enum TraceType {
+    QUEUE, /**< Trace queue events on the attached queue */
+    RX,    /**< Trace packet reception events (from the channel) */
+  };
+  /**
+   * Construct a PointToPointNetDevice
+   *
+   * This is the constructor for the PointToPointNetDevice.  It takes as a
+   * parameter the Node to which this device is connected.  Ownership of the
+   * Node pointer is not implied and the node must not be deleded.
+   *
+   * @see PointToPointTopology::AddPointToPointLink ()
+   * @param node the Node to which this device is connected.
+   */
+  PointToPointNetDevice (Ptr<Node> node,
+                         const DataRate& = g_defaultRate.GetValue());
+  /**
+   * Destroy a PointToPointNetDevice
+   *
+   * This is the destructor for the PointToPointNetDevice.
+   */
+  virtual ~PointToPointNetDevice();
+  /**
+   * Set the Data Rate used for transmission of packets.  The data rate is
+   * set in the Attach () method from the corresponding field in the channel
+   * to which the device is attached.  It can be overridden using this method.
+   *
+   * @see Attach ()
+   * @param bps the data rate at which this object operates
+   */
+  void SetDataRate(const DataRate& bps);
+  /**
+   * Set the inteframe gap used to separate packets.  The interframe gap
+   * defines the minimum space required between packets sent by this device.
+   * It is usually set in the Attach () method based on the speed of light
+   * delay of the channel to which the device is attached.  It can be 
+   * overridden using this method if desired.
+   *
+   * @see Attach ()
+   * @param t the interframe gap time
+   */
+  void SetInterframeGap(const Time& t);
+  /**
+   * Attach the device to a channel.
+   *
+   * The PointToPointTopology object creates a PointToPointChannel and two
+   * PointtoPointNetDevices.  In order to introduce these components to each
+   * other, the topology object calls Attach () on each PointToPointNetDevice.
+   * Inside this method, the Net Device calls out to the PointToPointChannel
+   * to introduce itself.
+   *
+   * @see PointToPointTopology::AddPointToPointLink ()
+   * @see SetDataRate ()
+   * @see SetInterframeGap ()
+   * @param ch a pointer to the channel to which this object is being attached.
+   */
+  bool Attach(Ptr<PointToPointChannel> ch);
+  /**
+   * Attach a queue to the PointToPointNetDevice.
+   *
+   * The PointToPointNetDevice "owns" a queue.  This queue is created by the
+   * PointToPointTopology object and implements a queueing method such as
+   * DropTail or RED.  The PointToPointNetDevice assumes ownership of this
+   * queue and must delete it when the device is destroyed.
+   *
+   * @see PointToPointTopology::AddPointToPointLink ()
+   * @see Queue
+   * @see DropTailQueue
+   * @param queue a pointer to the queue for which object is assuming
+   *        ownership.
+   */
+  void AddQueue(Ptr<Queue> queue);
+  /**
+   * Receive a packet from a connected PointToPointChannel.
+   *
+   * The PointToPointNetDevice receives packets from its connected channel
+   * and forwards them up the protocol stack.  This is the public method
+   * used by the channel to indicate that the last bit of a packet has 
+   * arrived at the device.
+   *
+   * @see PointToPointChannel
+   * @param p a reference to the received packet
+   */
+  void Receive (Packet& p);
+protected:
+  virtual void DoDispose (void);
+  /**
+   * Get a copy of the attached Queue.
+   *
+   * This method is provided for any derived class that may need to get
+   * direct access to the underlying queue.
+   *
+   * @see PointToPointTopology
+   * @returns a pointer to the queue.
+   */
+  Ptr<Queue> GetQueue(void) const; 
+  /**
+   * Get a copy of the attached Channel
+   *
+   * This method is provided for any derived class that may need to get
+   * direct access to the connected channel
+   *
+   * @see PointToPointChannel
+   * @returns a pointer to the channel
+   */
+  virtual Ptr<Channel> DoGetChannel(void) const;
+  /**
+   * Set a new default data rate
+   * @param Data rate to set for new default
+   */
+  static void SetDefaultRate(const DataRate&);
+
+  /** 
+   * Get the current default rate.
+   * @returns a const reference to current default
+   */
+
+  static const DataRate& GetDefaultRate();
+
+private:
+  // unimplemented methods to make it impossible
+  // to copy these objects.
+  PointToPointNetDevice (const PointToPointNetDevice& nd);
+  PointToPointNetDevice& operator = (const PointToPointNetDevice&o);
+  
+  /**
+   * Send a Packet Down the Wire.
+   *
+   * The SendTo method is defined as the standard way that the level three
+   * protocol uses to tell a NetDevice to send a packet.  SendTo is declared
+   * as abstract in the NetDevice class and we declare it here.
+   *
+   * @see NetDevice
+   * @param p a reference to the packet to send
+   * @param dest a reference to the MacAddress of the destination device
+   * @returns true if success, false on failure
+   */
+  virtual bool SendTo (Packet& p, const MacAddress& dest);
+  /**
+   * Start Sending a Packet Down the Wire.
+   *
+   * The TransmitStart method is the method that is used internally in the
+   * PointToPointNetDevice to begin the process of sending a packet out on
+   * the channel.  The corresponding method is called on the channel to let
+   * it know that the physical device this class represents has virually
+   * started sending signals.  An event is scheduled for the time at which
+   * the bits have been completely transmitted.
+   *
+   * @see PointToPointChannel::TransmitStart ()
+   * @see TransmitCompleteEvent ()
+   * @param p a reference to the packet to send
+   * @returns true if success, false on failure
+   */
+  bool TransmitStart (Packet &p);
+  /**
+   * Stop Sending a Packet Down the Wire and Begin the Interframe Gap.
+   *
+   * The TransmitComplete method is used internally to finish the process
+   * of sending a packet out on the channel.
+   *
+   */
+  void TransmitComplete(void);
+  /**
+   * Create a Trace Resolver for events in the net device.
+   *
+   * @see class TraceResolver
+   */
+  virtual TraceResolver* DoCreateTraceResolver (TraceContext const &context);
+  virtual bool DoNeedsArp (void) const;
+  /**
+   * Enumeration of the states of the transmit machine of the net device.
+   */
+  enum TxMachineState
+    {
+      READY, /**< The transmitter is ready to begin transmission of a packet */
+      BUSY   /**< The transmitter is busy transmitting a packet */
+    };
+  /**
+   * The state of the Net Device transmit state machine.
+   * @see TxMachineState
+   */
+  TxMachineState m_txMachineState;
+  /**
+   * The data rate that the Net Device uses to simulate packet transmission
+   * timing.
+   * @see class DataRate
+   */
+  DataRate       m_bps;
+  /**
+   * The interframe gap that the Net Device uses to throttle packet
+   * transmission
+   * @see class Time
+   */
+  Time           m_tInterframeGap;
+  /**
+   * The PointToPointChannel to which this PointToPointNetDevice has been
+   * attached.
+   * @see class PointToPointChannel
+   */
+  Ptr<PointToPointChannel> m_channel;
+  /**
+   * The Queue which this PointToPointNetDevice uses as a packet source.
+   * Management of this Queue has been delegated to the PointToPointNetDevice
+   * and it has the responsibility for deletion.
+   * @see class Queue
+   * @see class DropTailQueue
+   */
+  Ptr<Queue> m_queue;
+  /**
+   * The trace source for the packet reception events that the device can
+   * fire.
+   *
+   * @see class CallBackTraceSource
+   * @see class TraceResolver
+   */
+  CallbackTraceSource<Packet &> m_rxTrace;
+  /** 
+   * Default data rate.  Used for all newly created p2p net devices
+   */
+   static DataRateDefaultValue g_defaultRate;
+
+};
+
+}; // namespace ns3
+
+#endif // POINT_TO_POINT_NET_DEVICE_H
+
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/devices/point-to-point/p2p-topology.cc	Fri Jul 27 20:17:23 2007 +0200
@@ -0,0 +1,172 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+//
+// Copyright (c) 2006 Georgia Tech Research Corporation
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 2 as
+// published by the Free Software Foundation;
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+//
+// Author: George F. Riley<riley@ece.gatech.edu>
+//
+
+//
+// Topology helper for ns3.
+// George F. Riley, Georgia Tech, Spring 2007
+
+#include <algorithm>
+#include "ns3/assert.h"
+#include "ns3/debug.h"
+#include "ns3/fatal-error.h"
+#include "ns3/nstime.h"
+#include "ns3/internet-node.h"
+#include "ns3/ipv4-address.h"
+#include "ns3/ipv4.h"
+#include "ns3/queue.h"
+
+#include "p2p-channel.h"
+#include "p2p-net-device.h"
+#include "p2p-topology.h"
+
+namespace ns3 {
+
+Ptr<PointToPointChannel>
+PointToPointTopology::AddPointToPointLink(
+  Ptr<Node> n1,
+  Ptr<Node> n2,
+  const DataRate& bps,
+  const Time& delay)
+{
+  Ptr<PointToPointChannel> channel = Create<PointToPointChannel> (bps, delay);
+
+  Ptr<PointToPointNetDevice> net1 = Create<PointToPointNetDevice> (n1);
+
+  Ptr<Queue> q = Queue::CreateDefault ();
+  net1->AddQueue(q);
+  net1->Attach (channel);
+  
+  Ptr<PointToPointNetDevice> net2 = Create<PointToPointNetDevice> (n2);
+
+  q = Queue::CreateDefault ();
+  net2->AddQueue(q);
+  net2->Attach (channel);
+
+  return channel;
+}
+
+void
+PointToPointTopology::AddIpv4Addresses(
+  Ptr<const PointToPointChannel> chan,
+  Ptr<Node> n1, const Ipv4Address& addr1,
+  Ptr<Node> n2, const Ipv4Address& addr2)
+{
+
+  // Duplex link is assumed to be subnetted as a /30
+  // May run this unnumbered in the future?
+  Ipv4Mask netmask("255.255.255.252");
+  NS_ASSERT (netmask.IsMatch(addr1,addr2));
+
+  // The PointToPoint channel is used to find the relevant NetDevices
+  NS_ASSERT (chan->GetNDevices () == 2);
+  Ptr<NetDevice> nd1 = chan->GetDevice (0);
+  Ptr<NetDevice> nd2 = chan->GetDevice (1);
+  // Make sure that nd1 belongs to n1 and nd2 to n2
+  if ( (nd1->GetNode ()->GetId () == n2->GetId () ) && 
+       (nd2->GetNode ()->GetId () == n1->GetId () ) )
+    {
+      std::swap(nd1, nd2);
+    }
+  NS_ASSERT (nd1->GetNode ()->GetId () == n1->GetId ());
+  NS_ASSERT (nd2->GetNode ()->GetId () == n2->GetId ());
+  
+  Ptr<Ipv4> ip1 = n1->QueryInterface<Ipv4> (Ipv4::iid);
+  uint32_t index1 = ip1->AddInterface (nd1);
+
+  ip1->SetAddress (index1, addr1);
+  ip1->SetNetworkMask (index1, netmask);
+  ip1->SetUp (index1);
+
+  Ptr<Ipv4> ip2 = n2->QueryInterface<Ipv4> (Ipv4::iid);
+  uint32_t index2 = ip2->AddInterface (nd2);
+
+  ip2->SetAddress (index2, addr2);
+  ip2->SetNetworkMask (index2, netmask);
+  ip2->SetUp (index2);
+  
+}
+
+void
+PointToPointTopology::AddIpv4Routes (
+  Ptr<Node> n1, Ptr<Node> n2, Ptr<const PointToPointChannel> chan)
+{ 
+  // The PointToPoint channel is used to find the relevant NetDevices
+  NS_ASSERT (chan->GetNDevices () == 2);
+  Ptr<NetDevice> nd1 = chan->GetDevice (0);
+  Ptr<NetDevice> nd2 = chan->GetDevice (1);
+
+  // Assert that n1 is the Node owning one of the two NetDevices
+  // and make sure that nd1 corresponds to it
+  if (nd1->GetNode ()->GetId () == n1->GetId ())
+    {
+      ; // Do nothing
+    }
+  else if (nd2->GetNode ()->GetId () == n1->GetId ())
+    {
+      std::swap(nd1, nd2);
+    }
+  else
+    {
+      NS_FATAL_ERROR("P2PTopo: Node does not contain an interface on Channel");
+    }
+
+   // Assert that n2 is the Node owning one of the two NetDevices
+   // and make sure that nd2 corresponds to it
+  if (nd2->GetNode ()->GetId () != n2->GetId ())
+    {
+      NS_FATAL_ERROR("P2PTopo: Node does not contain an interface on Channel");
+    }
+
+  // Assert that both are Ipv4 nodes
+  Ptr<Ipv4> ip1 = nd1->GetNode ()->QueryInterface<Ipv4> (Ipv4::iid);
+  Ptr<Ipv4> ip2 = nd2->GetNode ()->QueryInterface<Ipv4> (Ipv4::iid);
+  NS_ASSERT(ip1 != 0 && ip2 != 0);
+
+  // Get interface indexes for both nodes corresponding to the right channel
+  uint32_t index1 = 0;
+  bool found = false;
+  for (uint32_t i = 0; i < ip1->GetNInterfaces (); i++)
+    {
+      if (ip1 ->GetNetDevice (i) == nd1)
+        {
+          index1 = i;
+          found = true;
+        }
+    }
+  NS_ASSERT(found);
+
+  uint32_t index2 = 0;
+  found = false;
+  for (uint32_t i = 0; i < ip2->GetNInterfaces (); i++)
+    {
+      if (ip2 ->GetNetDevice (i) == nd2)
+        {
+          index2 = i;
+          found = true;
+        }
+    }
+  NS_ASSERT(found);
+
+  ip1->AddHostRouteTo (ip2-> GetAddress (index2), index1);
+  ip2->AddHostRouteTo (ip1-> GetAddress (index1), index2); 
+}
+
+} // namespace ns3
+ 
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/devices/point-to-point/p2p-topology.h	Fri Jul 27 20:17:23 2007 +0200
@@ -0,0 +1,87 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+//
+// Copyright (c) 2006 Georgia Tech Research Corporation
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License version 2 as
+// published by the Free Software Foundation;
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+//
+// Author: George F. Riley<riley@ece.gatech.edu>
+//
+// Topology helper for ns3.
+// George F. Riley, Georgia Tech, Spring 2007
+#ifndef __POINT_TO_POINT_TOPOLOGY_H__
+#define __POINT_TO_POINT_TOPOLOGY_H__
+
+#include "ns3/ptr.h"
+
+// The topology class consists of only static methods thar are used to
+// create the topology and data flows for an ns3 simulation
+
+namespace ns3 {
+
+class PointToPointChannel;
+class Node;
+class IPAddr;
+class DataRate;
+class Queue;
+
+/**
+ * \brief A helper class to create Topologies based on the 
+ * ns3::PointToPointNetDevice and  ns3::PointToPointChannel objects.
+ */
+class PointToPointTopology {
+public:
+  /** 
+   * \param n1 Node
+   * \param n2 Node
+   * \param dataRate Maximum transmission link rate 
+   * \param delay one-way propagation delay 
+   * \return Pointer to the underlying PointToPointChannel
+   * 
+   * Add a full-duplex point-to-point link between two nodes
+   * and attach PointToPointNetDevices to the resulting
+   * PointToPointChannel.  
+   */
+  static Ptr<PointToPointChannel> AddPointToPointLink(
+    Ptr<Node> n1, Ptr<Node> n2, const DataRate& dataRate, const Time& delay);
+
+  /** 
+   * \param chan PointToPointChannel to use
+   * \param n1 Node
+   * \param addr1 Ipv4 Address for n1
+   * \param n2 Node
+   * \param addr2 Ipv4 Address for n2
+   * 
+   * Add Ipv4Addresses to the Ipv4 interfaces associated with the 
+   * two PointToPointNetDevices on the provided PointToPointChannel
+   */
+  static void AddIpv4Addresses(
+    Ptr<const PointToPointChannel> chan,
+    Ptr<Node> n1, const Ipv4Address& addr1,
+    Ptr<Node> n2, const Ipv4Address& addr2);
+
+  /**
+   * \param channel PointToPointChannel to use
+   * \param n1 Node
+   * \param n2 Node
+   * 
+   * For the given PointToPointChannel, for each Node, add an 
+   * IPv4 host route to the IPv4 address of the peer node.  
+   */
+  static void AddIpv4Routes (Ptr<Node> n1, Ptr<Node> n2, Ptr<const PointToPointChannel> channel);
+};
+
+} // namespace ns3
+
+#endif
+
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/devices/point-to-point/wscript	Fri Jul 27 20:17:23 2007 +0200
@@ -0,0 +1,22 @@
+## -*- Mode: python; py-indent-offset: 4; indent-tabs-mode: nil; coding: utf-8; -*-
+
+
+def build(bld):
+    p2p = bld.create_obj('cpp', 'shlib')
+    p2p.name = 'ns3-p2p'
+    p2p.target = p2p.name
+    p2p.uselib_local = ['ns3-node']
+    p2p.source = [
+        'p2p-net-device.cc',
+        'p2p-channel.cc',
+        'p2p-topology.cc',
+        ]
+    p2p.includes = '.'
+
+    headers = bld.create_obj('ns3header')
+    headers.source = [
+        'p2p-net-device.h',
+        'p2p-channel.h',
+        'p2p-topology.h',
+        ]
+
--- a/src/wscript	Thu Jul 26 16:04:54 2007 +0200
+++ b/src/wscript	Fri Jul 27 20:17:23 2007 +0200
@@ -15,7 +15,7 @@
     'simulator',
     'node',
     'internet-node',
-    'devices/p2p',
+    'devices/point-to-point',
     'applications',
     'mobility',
     )