diff --git a/SConstruct b/SConstruct
index 13f65b788..7161fe8a2 100644
--- a/SConstruct
+++ b/SConstruct
@@ -282,8 +282,6 @@ p2p.add_sources ([
     'p2p-net-device.cc',
     'p2p-channel.cc',
     'p2p-topology.cc',
-    'p2p-phy.cc',
-    'layer-connector.cc',
     ])
 p2p.add_headers ([
     'propagator.h',
@@ -292,8 +290,6 @@ p2p.add_inst_headers ([
     'p2p-net-device.h',
     'p2p-channel.h',
     'p2p-topology.h',
-    'p2p-phy.h',
-    'layer-connector.h',
     ])
 
 
diff --git a/examples/simple-p2p.cc b/examples/simple-p2p.cc
index 5410c7606..ea68b6b8c 100644
--- a/examples/simple-p2p.cc
+++ b/examples/simple-p2p.cc
@@ -207,7 +207,6 @@ int main (int argc, char *argv[])
   DebugComponentEnable("Channel");
   DebugComponentEnable("PointToPointChannel");
   DebugComponentEnable("PointToPointNetDevice");
-  DebugComponentEnable("PointToPointPhy");
 #endif
   ObjectContainer container;
 
diff --git a/src/devices/p2p/layer-connector.cc b/src/devices/p2p/layer-connector.cc
deleted file mode 100644
index 9134e9b1c..000000000
--- a/src/devices/p2p/layer-connector.cc
+++ /dev/null
@@ -1,138 +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.washingon.edu>
- *
- *      Fri Feb 16 12:18:11 PST 2007 craigdo:  created
- */
-
-#include "ns3/debug.h"
-#include "ns3/assert.h"
-#include "layer-connector.h"
-
-NS_DEBUG_COMPONENT_DEFINE ("LayerConnector");
-
-namespace ns3 {
-
-LayerConnectorUpper::LayerConnectorUpper ()
-{
-  NS_DEBUG("LayerConnectorUpper::LayerConnectorUpper ()");
-}
-
-LayerConnectorUpper::~LayerConnectorUpper ()
-{
-  NS_DEBUG("LayerConnectorUpper::~LayerConnectorUpper ()");
-}
-
-  bool
-LayerConnectorUpper::ConnectToLower (LayerConnectorLower &partner)
-{
-  NS_DEBUG("LayerConnectorUpper::ConnectToLower (" << &partner << ")");
-
-  return DoConnectToLower(partner);
-}
-
-  bool
-LayerConnectorUpper::DoConnectToLower (LayerConnectorLower &partner)
-{
-  NS_DEBUG("LayerConnectorUpper::DoConnectToLower (" << &partner << ")");
-
-  m_lowerPartner = &partner;
-  NS_ASSERT (m_lowerPartner);
-  return true;
-}
-
-  bool
-LayerConnectorUpper::UpperSendUp (Packet &p)
-{
-  NS_DEBUG("LayerConnectorUpper::UpperSendUp (" << &p << ")");
-
-  return UpperDoSendUp(p);
-}
-
-  bool
-LayerConnectorUpper::UpperPull (Packet &p)
-{
-  NS_DEBUG("LayerConnectorUpper::UpperPull (" << &p << ")");
-
-  return UpperDoPull(p);
-}
-
-  bool
-LayerConnectorUpper::UpperNotify ()
-{
-  NS_DEBUG("LayerConnectorUpper::UpperNotify ()");
-
-  NS_ASSERT (m_lowerPartner);
-  return m_lowerPartner->LowerNotify(this);
-}
-
-LayerConnectorLower::LayerConnectorLower ()
-{
-  NS_DEBUG("LayerConnectorLower::LayerConnectorLower ()");
-}
-
-LayerConnectorLower::~LayerConnectorLower ()
-{
-  NS_DEBUG("LayerConnectorLower::~LayerConnectorLower ()");
-}
-
-  bool
-LayerConnectorLower::ConnectToUpper (LayerConnectorUpper &partner)
-{
-  NS_DEBUG("LayerConnectorLower::ConnectToUpper (" << &partner << ")");
-
-  return DoConnectToUpper(partner);
-}
-
-  bool
-LayerConnectorLower::DoConnectToUpper (LayerConnectorUpper &partner)
-{
-  NS_DEBUG("LayerConnectorLower::DoConnectToUpper (" << &partner << ")");
-
-  m_upperPartner = &partner;
-  NS_ASSERT (m_upperPartner);
-  return true;
-}
-
-  bool
-LayerConnectorLower::LowerSendUp (Packet &p)
-{
-  NS_DEBUG("LayerConnectorLower::LowerSendUp (" << &p << ")");
-
-  NS_ASSERT (m_upperPartner);
-  return m_upperPartner->UpperSendUp(p);
-}
-
-  bool
-LayerConnectorLower::LowerPull (Packet &p)
-{
-  NS_DEBUG("LayerConnectorLower::LowerPull (" << &p << ")");
-
-  NS_ASSERT (m_upperPartner);
-  return m_upperPartner->UpperPull(p);
-}
-
-  bool
-LayerConnectorLower::LowerNotify (LayerConnectorUpper *upper)
-{
-  NS_DEBUG("LayerConnectorLower::LowerNotify ()");
-  return LowerDoNotify(upper);
-}
-
-} // namespace ns3
diff --git a/src/devices/p2p/layer-connector.h b/src/devices/p2p/layer-connector.h
deleted file mode 100644
index 0c3f37626..000000000
--- a/src/devices/p2p/layer-connector.h
+++ /dev/null
@@ -1,97 +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.washingon.edu>
- *
- *      Wed Feb 14 16:05:46 PST 2007 craigdo:  created
- */
-
-#include "ns3/packet.h"
-
-#ifndef LAYER_CONNECTOR_H
-#define LAYER_CONNECTOR_H
-
-namespace ns3 {
-
-class LayerConnectorLower;
-
-class LayerConnectorUpper {
-public:
-  LayerConnectorUpper ();
-  virtual ~LayerConnectorUpper ();
-
-  // called by the layer connector to introduce the lower interface to us here
-  bool ConnectToLower (LayerConnectorLower &lower);
-
-  // called by the lower layer to send a received packet on up the protocol
-  // stack to us here.
-  bool UpperSendUp (Packet &p);
-
-  // Call this function to tell a lower layer that there is data available
-  // here.  It is expected that the lower layer will call pull as soon as
-  // possible to get the data.
-  bool UpperNotify ();
-
-  // called by the lower layer to get available packet data that was implied
-  // by a previous Notify() call.
-  bool UpperPull(Packet &p);
-
-protected:
-  virtual bool DoConnectToLower (LayerConnectorLower &lower);
-  virtual bool UpperDoSendUp (Packet &p) = 0;
-  virtual bool UpperDoPull (Packet &p) = 0;
-
-  LayerConnectorLower *m_lowerPartner;
-
-private:
-};
-
-class LayerConnectorLower
-{
-public:
-  LayerConnectorLower ();
-  virtual ~LayerConnectorLower ();
-
-  // This function is called by the layer connector to introduce the upper
-  // layer interface to us here
-  bool ConnectToUpper (LayerConnectorUpper &upper);
-
-  // Notify is called by the upper layer connector to tell us that there
-  // is data available.  It is expected that we will call pull (below) as
-  // soon as possible to get the data.
-  bool LowerNotify (LayerConnectorUpper *upper);
-
-  // The lower connector calls this method to send a received packet on up 
-  // the protocol stack
-  bool LowerSendUp (Packet &p);
-
-  // Call this function to get available packet data from the upper connector
-  // that was implied by a previous Notify() call.
-  bool LowerPull(Packet &p);
-
-protected:
-  virtual bool DoConnectToUpper (LayerConnectorUpper &upper);
-  virtual bool LowerDoNotify (LayerConnectorUpper *upper) = 0;
-  LayerConnectorUpper *m_upperPartner;
-
-private:
-};
-
-}; // namespace ns3
-
-#endif /* LAYER_CONNECTOR_H */
diff --git a/src/devices/p2p/p2p-channel.cc b/src/devices/p2p/p2p-channel.cc
index 92d8e7d76..c0a8342b7 100644
--- a/src/devices/p2p/p2p-channel.cc
+++ b/src/devices/p2p/p2p-channel.cc
@@ -21,7 +21,6 @@
 
 #include "p2p-channel.h"
 #include "p2p-net-device.h"
-#include "p2p-phy.h"
 #include "ns3/packet.h"
 #include "ns3/simulator.h"
 #include "ns3/debug.h"
@@ -71,13 +70,13 @@ PointToPointChannel::PointToPointChannel(
 }
 
   void
-PointToPointChannel::Attach(PointToPointPhy *phy)
+PointToPointChannel::Attach(PointToPointNetDevice *device)
 {
-  NS_DEBUG("PointToPointChannel::Attach (" << phy << ")");
+  NS_DEBUG("PointToPointChannel::Attach (" << device << ")");
   NS_ASSERT(m_nDevices < N_DEVICES && "Only two devices permitted");
-  NS_ASSERT(phy);
+  NS_ASSERT(device);
 
-  m_link[m_nDevices].m_src = phy;
+  m_link[m_nDevices].m_src = device;
   ++m_nDevices;
 //
 // If we have both devices connected to the channel, then finish introducing
@@ -92,28 +91,13 @@ PointToPointChannel::Attach(PointToPointPhy *phy)
     }
 }
 
-void
-PointToPointChannel::TransmitCompleteEvent(Packet p, PointToPointPhy *src)
-{
-  NS_DEBUG("PointToPointChannel::TransmitCompleteEvent (" << &p << ", " << 
-    src << ")");
-
-  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;
-  NS_ASSERT(m_link[wire].m_state == TRANSMITTING);
-
-  m_link[wire].m_state = IDLE;
-  
-  NS_DEBUG("PointToPointChannel::TransmitCompleteEvent (): Receive()");
-
-  m_link[wire].m_dst->Receive (p);
-}
-
 bool
-PointToPointChannel::Propagate(Packet& p, PointToPointPhy* src)
+PointToPointChannel::TransmitStart(Packet& p, PointToPointNetDevice* src)
 {
-  NS_DEBUG("PointToPointChannel::DoPropagate (" << &p << ", " << src << ")");
+  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);
@@ -122,33 +106,86 @@ PointToPointChannel::Propagate(Packet& p, PointToPointPhy* src)
 
   if (m_link[wire].m_state == TRANSMITTING)
     {
-      NS_DEBUG("PointToPointChannel::DoPropagate (): TRANSMITTING, return");
+      NS_DEBUG("PointToPointChannel::TransmitStart (): **** ERROR ****");
+      NS_DEBUG("PointToPointChannel::TransmitStart (): state TRANSMITTING");
       return false;
     }
 
+  NS_DEBUG("PointToPointChannel::TransmitStart (): switch to TRANSMITTING");
   m_link[wire].m_state = TRANSMITTING;
-
-  Time txTime = Seconds (m_bps.CalculateTxTime(p.GetSize()));
-  Time tEvent = txTime + m_delay;
-
-  NS_DEBUG("PointToPointChannel::DoSend (): Schedule bps " << 
-    m_bps.GetBitRate() << " txTime " << m_bps.CalculateTxTime(p.GetSize()) << 
-    " prop delay " << m_delay << " Recv. delay " << tEvent);
-
-  Simulator::Schedule (tEvent, &PointToPointChannel::TransmitCompleteEvent, 
-                       this, p, src);
   return true;
 }
 
+bool
+PointToPointChannel::TransmitEnd(Packet& p, PointToPointNetDevice* src)
+{
+  NS_DEBUG("PointToPointChannel::TransmitEnd (" << &p << ", " << src << ")");
+  NS_DEBUG ("PointToPointChannel::TransmitEnd (): 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;
+
+  NS_ASSERT(m_link[wire].m_state == TRANSMITTING);
+
+  m_link[wire].m_state = PROPAGATING;
+//
+// The sender is going to free the packet as soon as it has been transmitted.
+// We need to copy it to get a reference so it won't e deleted.
+//
+  Packet packet = p;
+  NS_DEBUG ("PointToPointChannel::TransmitEnd (): Schedule event in " << 
+            m_delay.GetSeconds () << "sec");
+  Simulator::Schedule (m_delay,
+                       &PointToPointChannel::PropagationCompleteEvent,
+                       this, packet, src);
+  return true;
+}
+
+void
+PointToPointChannel::PropagationCompleteEvent(
+  Packet p, 
+  PointToPointNetDevice *src)
+{
+  NS_DEBUG("PointToPointChannel::PropagationCompleteEvent (" << &p << ", " << 
+    src << ")");
+  NS_DEBUG ("PointToPointChannel::PropagationCompleteEvent (): UID is " << 
+    p.GetUid () << ")");
+
+  uint32_t wire = src == m_link[0].m_src ? 0 : 1;
+  NS_ASSERT(m_link[wire].m_state == PROPAGATING);
+  m_link[wire].m_state = IDLE;
+
+  NS_DEBUG ("PointToPointChannel::PropagationCompleteEvent (): Receive");
+  m_link[wire].m_dst->Receive (p);
+}
+
+
 uint32_t 
 PointToPointChannel::GetNDevices (void) const
 {
   return m_nDevices;
 }
+
 NetDevice *
 PointToPointChannel::GetDevice (uint32_t i) const
 {
-  return m_link[i].m_src->GetDevice ();
+  NS_ASSERT(i < 2);
+  return m_link[i].m_src;
+}
+
+  DataRate
+PointToPointChannel::GetDataRate (void)
+{
+  return m_bps;
+}
+
+  Time
+PointToPointChannel::GetDelay (void)
+{
+  return m_delay;
 }
 
 
diff --git a/src/devices/p2p/p2p-channel.h b/src/devices/p2p/p2p-channel.h
index 445fa61e4..13256a2d7 100644
--- a/src/devices/p2p/p2p-channel.h
+++ b/src/devices/p2p/p2p-channel.h
@@ -27,22 +27,22 @@
 
 namespace ns3 {
 
-class PointToPointPhy;
-class NetDevice;
+class PointToPointNetDevice;
 
 /**
  * \brief Simple Point To Point Channel.
  *
- * This class represents a very simple serial 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 serial 
- * 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.
+ * 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 channel speed, in bits per second, and a delay time as a Time
- * object.  Both directions use the same speed and delay time.
+ * 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
@@ -62,16 +62,18 @@ public:
   PointToPointChannel (const std::string& name,
                  const DataRate& bps, const Time& delay);
 
-  void Attach (PointToPointPhy* phy);
-  bool Propagate (Packet& p, PointToPointPhy *src);
+  void Attach (PointToPointNetDevice* device);
+  bool TransmitStart (Packet& p, PointToPointNetDevice *src);
+  bool TransmitEnd (Packet &p, PointToPointNetDevice *src);
+  void PropagationCompleteEvent(Packet p, PointToPointNetDevice *src);
 
   virtual uint32_t GetNDevices (void) const;
   virtual NetDevice *GetDevice (uint32_t i) const;
 
+  virtual DataRate GetDataRate (void);
+  virtual Time GetDelay (void);
 
 private:
-  void TransmitCompleteEvent (Packet p, PointToPointPhy *src);
-
   DataRate      m_bps;
   Time          m_delay;
 
@@ -81,16 +83,17 @@ private:
     {
       INITIALIZING,
       IDLE,
-      TRANSMITTING
+      TRANSMITTING,
+      PROPAGATING
     };
 
   class Link
   {
   public:
     Link() : m_state (INITIALIZING), m_src (0), m_dst (0) {}
-    WireState        m_state;
-    PointToPointPhy *m_src;
-    PointToPointPhy *m_dst;
+    WireState              m_state;
+    PointToPointNetDevice *m_src;
+    PointToPointNetDevice *m_dst;
   };
     
   Link    m_link[N_DEVICES];
diff --git a/src/devices/p2p/p2p-net-device.cc b/src/devices/p2p/p2p-net-device.cc
index 3dcf57553..cd6d7f235 100644
--- a/src/devices/p2p/p2p-net-device.cc
+++ b/src/devices/p2p/p2p-net-device.cc
@@ -23,18 +23,21 @@
 #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"
-#include "p2p-phy.h"
 
 NS_DEBUG_COMPONENT_DEFINE ("PointToPointNetDevice");
 
 namespace ns3 {
 
-
-PointToPointNetDevice::PointToPointNetDevice(Node* node) : 
-  NetDevice(node, MacAddress("00:00:00:00:00:00")), m_phy(0), m_channel(0), 
+PointToPointNetDevice::PointToPointNetDevice(Node* node) 
+: 
+  NetDevice(node, MacAddress("00:00:00:00:00:00")), 
+  m_txMachineState(READY),
+  m_bps (DataRate(0xffffffff)),
+  m_channel(0), 
   m_queue(0)
 {
   NS_DEBUG ("PointToPointNetDevice::PointToPointNetDevice (" << node << ")");
@@ -45,21 +48,30 @@ PointToPointNetDevice::PointToPointNetDevice(Node* node) :
   EnableBroadcast (MacAddress ("ff:ff:ff:ff:ff:ff"));
   EnableMulticast();
   EnablePointToPoint();
-
-  m_phy = new PointToPointPhy(node, this);
 }
 
 PointToPointNetDevice::~PointToPointNetDevice()
 {
   NS_DEBUG ("PointToPointNetDevice::~PointToPointNetDevice ()");
-  delete m_phy;
 }
 
+  void 
+PointToPointNetDevice::SetDataRate(DataRate bps)
+{
+  m_bps = bps;
+}
 
-bool
+  void 
+PointToPointNetDevice::SetInterframeGap(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 () << ")");
 
   assert (IsLinkUp ());
 
@@ -68,12 +80,142 @@ PointToPointNetDevice::SendTo (Packet& p, const MacAddress& dest)
     tag.address = address;
     p.AddTag (tag);
 #endif
-    if (m_queue->Enqueue(p) )
+
+//
+// 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.  This is
+// not a requirement for a point-to-point link, but it's a typical model for
+// the device.  
+//
+// Generally, a real device will have a list of pending packets to transmit.  
+// An on-device CPU frees the main CPU(s) of the details of what is happening
+// in the device and feeds the USART.  The main CPU basically just sees the 
+// list of packets -- it puts packets into the list, and the device frees the
+// packets when they are transmitted.
+//
+// In the case of our virtual device here, the queue pointed to by m_queue
+// corresponds to this list.  The main CPU adds packets to the list by 
+// calling this method and when the device completes a send, the packets are
+// freed in an "interrupt" service routine.
+//
+// We're going to do the same thing here.  So first of all, the incoming packet
+// goes onto our queue if possible.  If the queue can't handle it, there's
+// nothing to be done.
+//
+    if (m_queue->Enqueue(p) == false )
       {
-        NotifyDataAvailable ();
-        return true;
+        return false;
       }
-    return false;
+//
+// If there's a transmission in progress, the "interrupt" will keep the
+// transmission process going.  If the device is idle, we need to start a
+// transmission.
+//
+// In the real world, the USART runs until it finishes sending bits, and then
+// pulls on the device's transmit complete interrupt wire.  At the same time,
+// the electrons from the last wiggle of the wire are busy propagating down
+// the wire.  In the case of a long speed-of-light delay in the wire, we could
+// conceivably start transmitting the next packet before the end of the 
+// previously sent data has even reached the end of the wire.  This situation
+// is usually avoided (like the plague) and an "interframe gap" is introduced.
+// This is usually the round-trip delay on the channel plus some hard-to-
+// quantify receiver turn-around time (the time required for the receiver
+// to process the last frame and prepare for reception of the next).
+//
+// So, if the transmit machine is ready, we need to schedule a transmit 
+// complete event (at which time we tell the channel we're no longer sending
+// bits).  A separate transmit ready event (at which time the transmitter 
+// becomes ready to start sending bits again is scheduled there).  Finally, 
+// we tell the channel (via TransmitStart ()) that we've started wiggling the 
+// wire and bits are coming out.
+//
+// If the transmit machine is not ready, we just leave and the transmit ready
+// event we know is coming will kick-start the transmit process.
+//
+    if (m_txMachineState == READY) 
+      {
+        return TransmitStart (p);
+      }
+    return true;
+}
+
+  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 it's time to tell the 
+// channel that we're done wiggling the wire.
+//
+  NS_ASSERT(m_txMachineState == READY && "Must be READY to transmit");
+  m_txMachineState = BUSY;
+  Time tEvent = Seconds (m_bps.CalculateTxTime(p.GetSize()));
+
+  NS_DEBUG ("PointToPointNetDevice::TransmitStart (): " <<
+    "Schedule TransmitCompleteEvent in " << 
+    tEvent.GetSeconds () << "sec");
+
+  Simulator::Schedule (tEvent, 
+                       &PointToPointNetDevice::TransmitCompleteEvent, 
+                       this);
+  return m_channel->TransmitStart (p, this); 
+}
+
+  void
+PointToPointNetDevice::TransmitCompleteEvent (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
+// schedule an event that will be executed when it's time to re-enable
+// the transmitter after the interframe gap.
+//
+  NS_ASSERT(m_txMachineState == BUSY && "Must be BUSY if transmitting");
+  m_txMachineState = GAP;
+  Packet p;
+  bool found = m_queue->Dequeue (p);
+  NS_ASSERT(found && "Packet must be on queue if transmitted");
+  NS_DEBUG ("PointToPointNetDevice::TransmitCompleteEvent (): Pkt UID is " << 
+            p.GetUid () << ")");
+  m_channel->TransmitEnd (p, this); 
+
+  NS_DEBUG (
+    "PointToPointNetDevice::TransmitCompleteEvent (): " <<
+    "Schedule TransmitReadyEvent in "
+    << m_tInterframeGap.GetSeconds () << "sec");
+
+  Simulator::Schedule (m_tInterframeGap, 
+                       &PointToPointNetDevice::TransmitReadyEvent, 
+                       this);
+}
+
+  void
+PointToPointNetDevice::TransmitReadyEvent (void)
+{
+  NS_DEBUG ("PointToPointNetDevice::TransmitReadyEvent ()");
+//
+// This function is called to enable the transmitter after the interframe
+// gap has passed.  If there are pending transmissions, we use this opportunity
+// to start the next transmit.
+//
+  NS_ASSERT(m_txMachineState == GAP && "Must be in interframe gap");
+  m_txMachineState = READY;
+
+  if (m_queue->IsEmpty())
+    {
+      return;
+    }
+  else
+    {
+      Packet p;
+      bool found = m_queue->Peek (p);
+      NS_ASSERT(found && "IsEmpty false but no Packet on queue?");
+      TransmitStart (p);
+    }
 }
 
 TraceResolver *
@@ -95,7 +237,11 @@ PointToPointNetDevice::Attach (PointToPointChannel* ch)
   NS_DEBUG ("PointToPointNetDevice::Attach (" << &ch << ")");
 
   m_channel = ch;
-  m_phy->Attach (m_channel);
+
+  m_channel->Attach(this);
+  m_bps = m_channel->GetDataRate ();
+  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
@@ -126,25 +272,6 @@ PointToPointNetDevice::Receive (Packet& p)
   ForwardUp (p);
 }
 
-void
-PointToPointNetDevice::NotifyDataAvailable(void)
-{
-  NS_DEBUG ("PointToPointNetDevice::NotifyDataAvailable ()");
-
-  Packet p;
-  bool found = GetQueue ()->Dequeue (p);
-  if (found)
-    {
-#ifdef NOTYET
-      struct NetDevicePacketDestAddress tag;
-      p.PeekTag (tag);
-      // send packet to address tag.address
-#endif
-      NS_DEBUG ("PointToPointNetDevice::NotifyDataAvailable (): Dequeued");
-      m_phy->Send(p);
-    }
-}
-
 Queue* 
 PointToPointNetDevice::GetQueue(void) const 
 { 
diff --git a/src/devices/p2p/p2p-net-device.h b/src/devices/p2p/p2p-net-device.h
index d3310a8ac..a42ba3946 100644
--- a/src/devices/p2p/p2p-net-device.h
+++ b/src/devices/p2p/p2p-net-device.h
@@ -28,11 +28,12 @@
 #include "ns3/callback.h"
 #include "ns3/packet.h"
 #include "ns3/callback-trace-source.h"
+#include "ns3/nstime.h"
+#include "ns3/data-rate.h"
 
 namespace ns3 {
 
 class PointToPointChannel;
-class PointToPointPhy;
 class Queue;
 
 class PointToPointNetDevice : public NetDevice {
@@ -41,9 +42,13 @@ public:
     QUEUE,
     RX,
   };
+
   PointToPointNetDevice(Node* node);
   virtual ~PointToPointNetDevice();
 
+  void SetDataRate(DataRate bps);
+  void SetInterframeGap(Time t);
+  
 private:
   // Don't let the compiler slip in copy and assignment construction
   PointToPointNetDevice(const PointToPointNetDevice&);
@@ -52,7 +57,6 @@ private:
 public:
   bool Attach(PointToPointChannel* ch);
   void AddQueue(Queue*);
-  // called by PointToPointPhy
   void Receive (Packet& p);
 
 protected:
@@ -60,11 +64,25 @@ protected:
   PointToPointChannel* GetChannel(void) const;
 
 private:
-  virtual void NotifyDataAvailable (void);
   virtual bool SendTo (Packet& p, const MacAddress& dest);
+
+  bool TransmitStart (Packet &p);
+  void TransmitCompleteEvent (void);
+  void TransmitReadyEvent (void);
+
   virtual TraceResolver *DoCreateTraceResolver (TraceContext const &context);
 
-  PointToPointPhy* m_phy;
+  enum TxMachineState
+    {
+      READY,
+      BUSY,
+      GAP
+    };
+
+  TxMachineState m_txMachineState;
+  DataRate       m_bps;
+  Time           m_tInterframeGap;
+
   PointToPointChannel* m_channel;
   Queue* m_queue;
   CallbackTraceSource<Packet &> m_rxTrace;
diff --git a/src/devices/p2p/p2p-phy.cc b/src/devices/p2p/p2p-phy.cc
deleted file mode 100644
index 86387fee5..000000000
--- a/src/devices/p2p/p2p-phy.cc
+++ /dev/null
@@ -1,71 +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: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
- */
-
-#include "ns3/debug.h"
-#include "ns3/queue.h"
-#include "p2p-phy.h"
-#include "p2p-net-device.h"
-#include "p2p-channel.h"
-
-NS_DEBUG_COMPONENT_DEFINE ("PointToPointPhy");
-
-namespace ns3 {
-
-PointToPointPhy::PointToPointPhy(Node* node, PointToPointNetDevice* netdevice) :
-  m_node(node), m_netdevice(netdevice)
-{
-  NS_DEBUG ("PointToPointPhy::PointToPointPhy (" << node << ", " << 
-    netdevice << ")");
-}
-
-PointToPointPhy::~PointToPointPhy()
-{
-  NS_DEBUG ("PointToPointPhy::~PointToPointPhy ()");
-}
-
-void 
-PointToPointPhy::Send (Packet &p)
-{
-  m_channel->Propagate (p, this);
-}
-void 
-PointToPointPhy::Attach (PointToPointChannel *channel)
-{
-  m_channel = channel;
-  m_channel->Attach (this);
-}
-
-PointToPointNetDevice *
-PointToPointPhy::GetDevice (void)
-{
-  return m_netdevice;
-}
-
-
-
-void
-PointToPointPhy::Receive (Packet& p)
-{
-  NS_DEBUG ("PointToPointPhy::Receive (" << &p << ")");
-  m_netdevice->Receive (p);
-}
-
-} // namespace ns3
diff --git a/src/devices/p2p/p2p-phy.h b/src/devices/p2p/p2p-phy.h
deleted file mode 100644
index 929a6543d..000000000
--- a/src/devices/p2p/p2p-phy.h
+++ /dev/null
@@ -1,50 +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_PHY_H
-#define POINT_TO_POINT_PHY_H
-
-namespace ns3 {
-
-class PointToPointNetDevice;
-class PointToPointChannel;
-class Node;
-class Packet;
-
-class PointToPointPhy {
-public:
-  PointToPointPhy(Node* node, PointToPointNetDevice* netdevice);
-  virtual ~PointToPointPhy();
-
-  void Send (Packet &p);
-  void Receive (Packet& p);
-  void Attach (PointToPointChannel *channel);
-
-  PointToPointNetDevice *GetDevice (void);
-
-private:
-  Node* m_node;
-  PointToPointChannel *m_channel;
-  PointToPointNetDevice* m_netdevice;
-};
-
-} // namespace ns3
-
-#endif // POINT_TO_POINT_PHY_H
diff --git a/src/devices/p2p/propagator.h b/src/devices/p2p/propagator.h
deleted file mode 100644
index e7ae002bb..000000000
--- a/src/devices/p2p/propagator.h
+++ /dev/null
@@ -1,49 +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.washingon.edu>
- *
- *      Thu Feb 15 15:06:15 PST 2007 craigdo:  Created
- */
-
-#ifndef PROPAGATOR_H
-#define PROPAGATOR_H
-
-#include "ns3/packet.h"
-
-namespace ns3 {
-
-class Propagator
-{
-public:
-  Propagator () : m_packet(0) {}
-  virtual ~Propagator () {}
-
-  void SetPacket (Packet &p) {DoSetPacket(p);}
-
-protected:
-  virtual void DoSetPacket (Packet &p) {m_packet = static_cast<Packet *>(&p);}
-
-  Packet *m_packet;
-private:
-};
-
-
-}; // namespace ns3
-
-#endif /* SERIAL_PHY_H */
diff --git a/src/node/drop-tail.cc b/src/node/drop-tail.cc
index b65c4d828..6585db6f2 100644
--- a/src/node/drop-tail.cc
+++ b/src/node/drop-tail.cc
@@ -101,4 +101,20 @@ DropTailQueue::DoDequeue (Packet& p)
   return true;
 }
 
+bool
+DropTailQueue::DoPeek (Packet& p)
+{
+  NS_DEBUG("DropTailQueue::DoPeek (" << &p << ")");
+
+  if (m_packets.empty()) 
+    {
+      NS_DEBUG("DropTailQueue::DoPeek (): Queue empty");
+      return false;
+    }
+
+  p = m_packets.front ();
+
+  return true;
+}
+
 }; // namespace ns3
diff --git a/src/node/drop-tail.h b/src/node/drop-tail.h
index da3749833..99e52e4f9 100644
--- a/src/node/drop-tail.h
+++ b/src/node/drop-tail.h
@@ -43,6 +43,7 @@ public:
 private:
   virtual bool DoEnqueue (const Packet& p);
   virtual bool DoDequeue (Packet &p);
+  virtual bool DoPeek (Packet &p);
 
 private:
   std::queue<Packet> m_packets;
diff --git a/src/node/net-device.h b/src/node/net-device.h
index f2ebb66b6..4b30ebf75 100644
--- a/src/node/net-device.h
+++ b/src/node/net-device.h
@@ -50,7 +50,7 @@ class TraceContext;
  * constructed with destination MAC address already selected).
  * 
  * If you want to write a new MAC layer, you need to subclass
- * this base class and implement your own version of the 
+ * this base class and implement your own version of the
  * NetDevice::SendTo method.
  */
 class NetDevice {
@@ -190,7 +190,7 @@ class NetDevice {
    * \returns true if the packet was forwarded successfully,
    *          false otherwise.
    *
-   * When a subclass gets a packet from the PHY layer, it 
+   * When a subclass gets a packet from the channel, it 
    * forwards it to the higher layers by calling this method
    * which is responsible for passing it up to the Rx callback.
    */
@@ -205,10 +205,10 @@ class NetDevice {
    *
    * This is the private virtual target function of the public Send()
    * method.  When the link is Up, this method is invoked to ask 
-   * subclasses to forward packets down to the PHY layer. Subclasses 
-   * MUST override this method.
+   * subclasses to forward packets. Subclasses MUST override this method.
    */
   virtual bool SendTo (Packet& p, const MacAddress& dest) = 0;
+
   virtual TraceResolver *DoCreateTraceResolver (TraceContext const &context) = 0;
   Node*         m_node;
   std::string   m_name;
diff --git a/src/node/queue.cc b/src/node/queue.cc
index 5567f9041..dbea2d964 100644
--- a/src/node/queue.cc
+++ b/src/node/queue.cc
@@ -103,6 +103,15 @@ Queue::DequeueAll (void)
   NS_ASSERT (!"Don't know what to do with dequeued packets!");
 }
 
+bool
+Queue::Peek (Packet &p)
+{
+  NS_DEBUG("Queue::Peek (" << &p << ")");
+
+  return DoPeek (p);
+}
+
+
 uint32_t 
 Queue::GetNPackets (void)
 {
diff --git a/src/node/queue.h b/src/node/queue.h
index ba7cd6e62..ac7736ff4 100644
--- a/src/node/queue.h
+++ b/src/node/queue.h
@@ -50,6 +50,7 @@ public:
   bool IsEmpty (void);
   bool Enqueue (const Packet& p);
   bool Dequeue (Packet &p);
+  bool Peek (Packet &p);
 
   void DequeueAll (void);
   uint32_t GetNPackets (void);
@@ -89,6 +90,7 @@ public:
 private:
   virtual bool DoEnqueue (const Packet& p) = 0;
   virtual bool DoDequeue (Packet &p) = 0;
+  virtual bool DoPeek (Packet &p) = 0;
 
 protected:
   // called by subclasses to notify parent of packet drops.