--- a/examples/wifi-ap.cc	Thu Jun 12 11:14:54 2008 -0700
+++ b/examples/wifi-ap.cc	Thu Jun 12 11:55:22 2008 -0700
@@ -173,10 +173,10 @@
 
   Config::Connect ("/NodeList/*/DeviceList/*/Tx", MakeCallback (&DevTxTrace));
   Config::Connect ("/NodeList/*/DeviceList/*/Rx", MakeCallback (&DevRxTrace));
-  Config::Connect ("/NodeList/*/DeviceList/*/Phy/RxOk", MakeCallback (&PhyRxOkTrace));
-  Config::Connect ("/NodeList/*/DeviceList/*/Phy/RxError", MakeCallback (&PhyRxErrorTrace));
-  Config::Connect ("/NodeList/*/DeviceList/*/Phy/Tx", MakeCallback (&PhyTxTrace));
-  Config::Connect ("/NodeList/*/DeviceList/*/Phy/State", MakeCallback (&PhyStateTrace));
+  Config::Connect ("/NodeList/*/DeviceList/*/Phy/State/RxOk", MakeCallback (&PhyRxOkTrace));
+  Config::Connect ("/NodeList/*/DeviceList/*/Phy/State/RxError", MakeCallback (&PhyRxErrorTrace));
+  Config::Connect ("/NodeList/*/DeviceList/*/Phy/State/Tx", MakeCallback (&PhyTxTrace));
+  Config::Connect ("/NodeList/*/DeviceList/*/Phy/State/State", MakeCallback (&PhyStateTrace));
 
   Simulator::Run ();
 

--- a/src/devices/wifi/wifi-phy-state-helper.cc	Thu Jun 12 11:14:54 2008 -0700
+++ b/src/devices/wifi/wifi-phy-state-helper.cc	Thu Jun 12 11:55:22 2008 -0700
@@ -20,11 +20,33 @@
 #include "wifi-phy-state-helper.h"
 #include "ns3/log.h"
 #include "ns3/simulator.h"
+#include "ns3/trace-source-accessor.h"
 
 NS_LOG_COMPONENT_DEFINE ("WifiPhyStateHelper");
 
 namespace ns3 {
 
+TypeId 
+WifiPhyStateHelper::GetTypeId (void)
+{
+  static TypeId tid = TypeId ("ns3::WifiPhyStateHelper")
+    .SetParent<Object> ()
+    .AddConstructor<WifiPhyStateHelper> ()
+    .AddTraceSource ("State",
+                     "The state of the PHY layer",
+                     MakeTraceSourceAccessor (&WifiPhyStateHelper::m_stateLogger))
+    .AddTraceSource ("RxOk",
+                     "A packet has been received successfully.",
+                     MakeTraceSourceAccessor (&WifiPhyStateHelper::m_rxOkTrace))
+    .AddTraceSource ("RxError",
+                     "A packet has been received unsuccessfully.",
+                     MakeTraceSourceAccessor (&WifiPhyStateHelper::m_rxErrorTrace))
+    .AddTraceSource ("Tx", "Packet transmission is starting.",
+                     MakeTraceSourceAccessor (&WifiPhyStateHelper::m_txTrace))
+    ;
+  return tid;
+}
+
 WifiPhyStateHelper::WifiPhyStateHelper ()
   : m_syncing (false),
     m_endTx (Seconds (0)),

--- a/src/devices/wifi/wifi-phy-state-helper.h	Thu Jun 12 11:14:54 2008 -0700
+++ b/src/devices/wifi/wifi-phy-state-helper.h	Thu Jun 12 11:55:22 2008 -0700
@@ -22,13 +22,16 @@
 
 #include "wifi-phy.h"
 #include "ns3/traced-callback.h"
+#include "ns3/object.h"
 #include <vector>
 
 namespace ns3 {
 
-class WifiPhyStateHelper
+class WifiPhyStateHelper : public Object
 {
 public:
+  static TypeId GetTypeId (void);
+
   WifiPhyStateHelper ();
 
   void SetReceiveOkCallback (WifiPhy::SyncOkCallback callback);
@@ -50,6 +53,7 @@
   void SwitchFromSyncEndError (Ptr<const Packet> packet, double snr);
   void SwitchMaybeToCcaBusy (Time duration);
 
+  TracedCallback<Time,Time,enum WifiPhy::State> m_stateLogger;
 private:
   typedef std::vector<WifiPhyListener *> Listeners;
 
@@ -72,7 +76,7 @@
   Time m_startSync;
   Time m_startCcaBusy;
   Time m_previousStateChangeTime;
-  TracedCallback<Time,Time,enum WifiPhy::State> m_stateLogger;
+
   Listeners m_listeners;
   TracedCallback<Ptr<const Packet>, double, WifiMode, enum WifiPreamble> m_rxOkTrace;
   TracedCallback<Ptr<const Packet>, double> m_rxErrorTrace;

--- a/src/devices/wifi/yans-wifi-phy.cc	Thu Jun 12 11:14:54 2008 -0700
+++ b/src/devices/wifi/yans-wifi-phy.cc	Thu Jun 12 11:55:22 2008 -0700
@@ -19,9 +19,10 @@
  */
 
 #include "yans-wifi-phy.h"
+#include "yans-wifi-channel.h"
 #include "wifi-mode.h"
-#include "yans-wifi-channel.h"
 #include "wifi-preamble.h"
+#include "wifi-phy-state-helper.h"
 #include "ns3/simulator.h"
 #include "ns3/packet.h"
 #include "ns3/random-variable.h"
@@ -30,7 +31,7 @@
 #include "ns3/double.h"
 #include "ns3/uinteger.h"
 #include "ns3/enum.h"
-#include "ns3/trace-source-accessor.h"
+#include "ns3/pointer.h"
 #include <math.h>
 
 NS_LOG_COMPONENT_DEFINE ("YansWifiPhy");
@@ -197,19 +198,10 @@
                    MakeEnumAccessor (&YansWifiPhy::SetStandard),
                    MakeEnumChecker (WIFI_PHY_STANDARD_80211a, "802.11a",
                                     WIFI_PHY_STANDARD_holland, "holland"))
-#if 0
-    .AddTraceSource ("State",
-                     "The YansWifiPhy state",
-                     MakeTraceSourceAccessor (&YansWifiPhy::m_stateLogger))
-    .AddTraceSource ("RxOk",
-                     "A packet has been received successfully.",
-                     MakeTraceSourceAccessor (&YansWifiPhy::m_rxOkTrace))
-    .AddTraceSource ("RxError",
-                     "A packet has been received unsuccessfully.",
-                     MakeTraceSourceAccessor (&YansWifiPhy::m_rxErrorTrace))
-    .AddTraceSource ("Tx", "Packet transmission is starting.",
-                     MakeTraceSourceAccessor (&YansWifiPhy::m_txTrace))
-#endif
+    .AddAttribute ("State", "The state of the PHY layer",
+                   PointerValue (),
+                   MakePointerAccessor (&YansWifiPhy::m_state),
+                   MakePointerChecker<WifiPhyStateHelper> ())
     ;
   return tid;
 }
@@ -219,6 +211,7 @@
    m_random (0.0, 1.0)
 {
   NS_LOG_FUNCTION (this);
+  m_state = CreateObject<WifiPhyStateHelper> ();
 }
 
 YansWifiPhy::~YansWifiPhy ()
@@ -343,12 +336,12 @@
 void 
 YansWifiPhy::SetReceiveOkCallback (SyncOkCallback callback)
 {
-  m_state.SetReceiveOkCallback (callback);
+  m_state->SetReceiveOkCallback (callback);
 }
 void 
 YansWifiPhy::SetReceiveErrorCallback (SyncErrorCallback callback)
 {
-  m_state.SetReceiveErrorCallback (callback);
+  m_state->SetReceiveErrorCallback (callback);
 }
 void 
 YansWifiPhy::StartReceivePacket (Ptr<Packet> packet, 
@@ -369,11 +362,11 @@
                                         rxPowerW);
   AppendEvent (event);
 
-  switch (m_state.GetState ()) {
+  switch (m_state->GetState ()) {
   case YansWifiPhy::SYNC:
     NS_LOG_DEBUG ("drop packet because already in Sync (power="<<
                   rxPowerW<<"W)");
-    if (endRx > Simulator::Now () + m_state.GetDelayUntilIdle ()) 
+    if (endRx > Simulator::Now () + m_state->GetDelayUntilIdle ()) 
       {
         // that packet will be noise _after_ the reception of the
         // currently-received packet.
@@ -383,7 +376,7 @@
   case YansWifiPhy::TX:
     NS_LOG_DEBUG ("drop packet because already in Tx (power="<<
                   rxPowerW<<"W)");
-    if (endRx > Simulator::Now () + m_state.GetDelayUntilIdle ()) 
+    if (endRx > Simulator::Now () + m_state->GetDelayUntilIdle ()) 
       {
         // that packet will be noise _after_ the transmission of the
         // currently-transmitted packet.
@@ -396,7 +389,7 @@
       {
         NS_LOG_DEBUG ("sync (power="<<rxPowerW<<"W)");
         // sync to signal
-        m_state.SwitchToSync (rxDuration);
+        m_state->SwitchToSync (rxDuration);
         NS_ASSERT (m_endSyncEvent.IsExpired ());
         m_endSyncEvent = Simulator::Schedule (rxDuration, &YansWifiPhy::EndSync, this, 
                                               packet,
@@ -417,7 +410,7 @@
 
   if (rxPowerW > m_edThresholdW) 
     {
-      m_state.SwitchMaybeToCcaBusy (rxDuration);
+      m_state->SwitchMaybeToCcaBusy (rxDuration);
     } 
   else 
     {
@@ -438,7 +431,7 @@
       if (end > Simulator::Now ()) 
         {
           Time delta = end - Simulator::Now ();
-          m_state.SwitchMaybeToCcaBusy (delta);
+          m_state->SwitchMaybeToCcaBusy (delta);
         }
     }
 
@@ -453,14 +446,14 @@
    *    prevent it.
    *  - we are idle
    */
-  NS_ASSERT (!m_state.IsStateTx ());
+  NS_ASSERT (!m_state->IsStateTx ());
 
   Time txDuration = CalculateTxDuration (packet->GetSize (), txMode, preamble);
-  if (m_state.IsStateSync ())
+  if (m_state->IsStateSync ())
     {
       m_endSyncEvent.Cancel ();
     }
-  m_state.SwitchToTx (txDuration, packet, txMode, preamble, txPower);
+  m_state->SwitchToTx (txDuration, packet, txMode, preamble, txPower);
   m_channel->Send (this, packet, GetPowerDbm (txPower) + m_txGainDb, txMode, preamble);
 }
 
@@ -567,51 +560,51 @@
 void 
 YansWifiPhy::RegisterListener (WifiPhyListener *listener)
 {
-  m_state.RegisterListener (listener);
+  m_state->RegisterListener (listener);
 }
 
 bool 
 YansWifiPhy::IsStateCcaBusy (void)
 {
-  return m_state.IsStateCcaBusy ();
+  return m_state->IsStateCcaBusy ();
 }
 
 bool 
 YansWifiPhy::IsStateIdle (void)
 {
-  return m_state.IsStateIdle ();
+  return m_state->IsStateIdle ();
 }
 bool 
 YansWifiPhy::IsStateBusy (void)
 {
-  return m_state.IsStateBusy ();
+  return m_state->IsStateBusy ();
 }
 bool 
 YansWifiPhy::IsStateSync (void)
 {
-  return m_state.IsStateSync ();
+  return m_state->IsStateSync ();
 }
 bool 
 YansWifiPhy::IsStateTx (void)
 {
-  return m_state.IsStateTx ();
+  return m_state->IsStateTx ();
 }
 
 Time
 YansWifiPhy::GetStateDuration (void)
 {
-  return m_state.GetStateDuration ();
+  return m_state->GetStateDuration ();
 }
 Time
 YansWifiPhy::GetDelayUntilIdle (void)
 {
-  return m_state.GetDelayUntilIdle ();
+  return m_state->GetDelayUntilIdle ();
 }
 
 Time 
 YansWifiPhy::GetLastRxStartTime (void) const
 {
-  return m_state.GetLastRxStartTime ();
+  return m_state->GetLastRxStartTime ();
 }
 
 
@@ -1126,12 +1119,12 @@
   
   if (m_random.GetValue () > per) 
     {
-      m_state.SwitchFromSyncEndOk (packet, snr, event->GetPayloadMode (), event->GetPreambleType ());
+      m_state->SwitchFromSyncEndOk (packet, snr, event->GetPayloadMode (), event->GetPreambleType ());
     } 
   else 
     {
       /* failure. */
-      m_state.SwitchFromSyncEndError (packet, snr);
+      m_state->SwitchFromSyncEndError (packet, snr);
     }
 }
 

--- a/src/devices/wifi/yans-wifi-phy.h	Thu Jun 12 11:14:54 2008 -0700
+++ b/src/devices/wifi/yans-wifi-phy.h	Thu Jun 12 11:55:22 2008 -0700
@@ -36,7 +36,6 @@
 #include "wifi-mode.h"
 #include "wifi-preamble.h"
 #include "wifi-phy-standard.h"
-#include "wifi-phy-state-helper.h"
 
 
 namespace ns3 {
@@ -44,6 +43,7 @@
 class RandomUniform;
 class RxEvent;
 class YansWifiChannel;
+class WifiPhyStateHelper;
 
 
 /**
@@ -180,15 +180,13 @@
   double   m_txPowerEndDbm;
   uint32_t m_nTxPower;
 
-  
-
   Ptr<YansWifiChannel> m_channel;
   Modes m_modes;
   EventId m_endSyncEvent;
   Events m_events;
   UniformVariable m_random;
   WifiPhyStandard m_standard;
-  WifiPhyStateHelper m_state;
+  Ptr<WifiPhyStateHelper> m_state;
 };
 
 } // namespace ns3

--- a/src/helper/wifi-helper.cc	Thu Jun 12 11:14:54 2008 -0700
+++ b/src/helper/wifi-helper.cc	Thu Jun 12 11:55:22 2008 -0700
@@ -137,10 +137,10 @@
   pcap->Open (oss.str ());
   pcap->WriteWifiHeader ();
   oss.str ("");
-  oss << "/NodeList/" << nodeid << "/DeviceList/" << deviceid << "/$ns3::WifiNetDevice/Phy/Tx";
+  oss << "/NodeList/" << nodeid << "/DeviceList/" << deviceid << "/$ns3::WifiNetDevice/Phy/State/Tx";
   Config::ConnectWithoutContext (oss.str (), MakeBoundCallback (&PcapPhyTxEvent, pcap));
   oss.str ("");
-  oss << "/NodeList/" << nodeid << "/DeviceList/" << deviceid << "/$ns3::WifiNetDevice/Phy/RxOk";
+  oss << "/NodeList/" << nodeid << "/DeviceList/" << deviceid << "/$ns3::WifiNetDevice/Phy/State/RxOk";
   Config::ConnectWithoutContext (oss.str (), MakeBoundCallback (&PcapPhyRxEvent, pcap));
 }
 void 
@@ -178,10 +178,10 @@
 {
     Packet::EnableMetadata ();
   std::ostringstream oss;
-  oss << "/NodeList/" << nodeid << "/DeviceList/" << deviceid << "/$ns3::WifiNetDevice/Phy/RxOk";
+  oss << "/NodeList/" << nodeid << "/DeviceList/" << deviceid << "/$ns3::WifiNetDevice/Phy/State/RxOk";
   Config::Connect (oss.str (), MakeBoundCallback (&AsciiPhyRxOkEvent, &os));
   oss.str ("");
-  oss << "/NodeList/" << nodeid << "/DeviceList/" << deviceid << "/$ns3::WifiNetDevice/Phy/Tx";
+  oss << "/NodeList/" << nodeid << "/DeviceList/" << deviceid << "/$ns3::WifiNetDevice/Phy/State/Tx";
   Config::Connect (oss.str (), MakeBoundCallback (&AsciiPhyTxEvent, &os));
 }
 void