--- a/src/devices/wifi/arf-wifi-manager.cc	Wed Jun 23 06:43:21 2010 +0200
+++ b/src/devices/wifi/arf-wifi-manager.cc	Wed Jun 23 08:47:29 2010 +0100
@@ -156,7 +156,7 @@
   NS_LOG_DEBUG ("station=" << station << " data ok success=" << station->m_success << ", timer=" << station->m_timer);
   if ((station->m_success == m_successThreshold ||
        station->m_timer == m_timerThreshold) &&
-      (station->m_rate < (station->m_state->m_modes.size () - 1))) 
+      (station->m_rate < (station->m_state->m_operationalRateSet.size () - 1)))
     {
       NS_LOG_DEBUG ("station="<<station<<" inc rate");
       station->m_rate++;

--- a/src/devices/wifi/wifi-mode.h	Wed Jun 23 06:43:21 2010 +0200
+++ b/src/devices/wifi/wifi-mode.h	Wed Jun 23 08:47:29 2010 +0100
@@ -163,6 +163,15 @@
 ATTRIBUTE_HELPER_HEADER (WifiMode);
 
 /**
+ * In various parts of the code, folk are interested in maintaining a
+ * list of transmission modes. The vector class provides a good basis
+ * for this, but we here add some syntactic sugar by defining a
+ * WifiModeList type, and a corresponding iterator.
+ */
+typedef std::vector<WifiMode> WifiModeList;
+typedef WifiModeList::const_iterator WifiModeListIterator;
+
+/**
  * \brief create WifiMode class instances and keep track of them.
  *
  * This factory ensures that each WifiMode created has a unique name

--- a/src/devices/wifi/wifi-phy.h	Wed Jun 23 06:43:21 2010 +0200
+++ b/src/devices/wifi/wifi-phy.h	Wed Jun 23 08:47:29 2010 +0100
@@ -240,14 +240,42 @@
    *          the transmission of these bytes.
    */
   virtual Time CalculateTxDuration (uint32_t size, WifiMode payloadMode, enum WifiPreamble preamble) const = 0;
-  
+
   /**
+   * The WifiPhy::GetNModes() and WifiPhy::GetMode() methods are used
+   * (e.g., by a WifiRemoteStationManager) to determine the set of
+   * transmission/reception modes that this WifiPhy(-derived class)
+   * can support - a set of WifiMode objects which we call the
+   * DeviceRateSet, and which is stored as WifiPhy::m_deviceRateSet.
+   *
+   * It is important to note that the DeviceRateSet is a superset (not
+   * necessarily proper) of the OperationalRateSet (which is
+   * logically, if not actually, a property of the associated
+   * WifiRemoteStationManager), which itself is a superset (again, not
+   * necessarily proper) of the BSSBasicRateSet.
+   *
    * \returns the number of transmission modes supported by this PHY.
+   *
+   * \sa WifiPhy::GetMode()
    */
   virtual uint32_t GetNModes (void) const = 0;
   /**
+   * The WifiPhy::GetNModes() and WifiPhy::GetMode() methods are used
+   * (e.g., by a WifiRemoteStationManager) to determine the set of
+   * transmission/reception modes that this WifiPhy(-derived class)
+   * can support - a set of WifiMode objects which we call the
+   * DeviceRateSet, and which is stored as WifiPhy::m_deviceRateSet.
+   *
+   * It is important to note that the DeviceRateSet is a superset (not
+   * necessarily proper) of the OperationalRateSet (which is
+   * logically, if not actually, a property of the associated
+   * WifiRemoteStationManager), which itself is a superset (again, not
+   * necessarily proper) of the BSSBasicRateSet.
+   *
    * \param mode index in array of supported modes
    * \returns the mode whose index is specified.
+   *
+   * \sa WifiPhy::GetNModes()
    */
   virtual WifiMode GetMode (uint32_t mode) const = 0;
   /**

--- a/src/devices/wifi/wifi-remote-station-manager.cc	Wed Jun 23 06:43:21 2010 +0200
+++ b/src/devices/wifi/wifi-remote-station-manager.cc	Wed Jun 23 08:47:29 2010 +0100
@@ -205,6 +205,12 @@
 void
 WifiRemoteStationManager::SetupPhy (Ptr<WifiPhy> phy)
 {
+  // We need to track our PHY because it is the object that knows the
+  // full set of transmit rates that are supported. We need to know
+  // this in order to find the relevant mandatory rates when chosing a
+  // transmit rate for automatic control responses like
+  // acknowledgements.
+  m_wifiPhy = phy;
   m_defaultTxMode = phy->GetMode (0);
   Reset ();
 }
@@ -255,7 +261,7 @@
 {
   NS_ASSERT (!address.IsGroup ());
   WifiRemoteStationState *state = LookupState (address);
-  state->m_modes.clear ();
+  state->m_operationalRateSet.clear ();
   AddSupportedMode (address, GetDefaultMode ());
 }
 void
@@ -263,7 +269,7 @@
 {
   NS_ASSERT (!address.IsGroup ());
   WifiRemoteStationState *state = LookupState (address);
-  for (WifiRemoteStationState::SupportedModes::const_iterator i = state->m_modes.begin (); i != state->m_modes.end (); i++)
+  for (WifiModeListIterator i = state->m_operationalRateSet.begin (); i != state->m_operationalRateSet.end (); i++)
     {
       if ((*i) == mode)
         {
@@ -271,7 +277,7 @@
           return;
         }
     }
-  state->m_modes.push_back (mode);
+  state->m_operationalRateSet.push_back (mode);
 }
 bool
 WifiRemoteStationManager::IsBrandNew (Mac48Address address) const
@@ -533,39 +539,105 @@
 WifiRemoteStationManager::GetControlAnswerMode (Mac48Address address, WifiMode reqMode)
 {
   /**
-   * see ieee 802.11e, section 9.6:
-   * 
-   * To allow the transmitting STA to calculate the contents of 
-   * the Duration/ID field, a STA responding to a received frame 
-   * shall transmit its Control Response frame (either CTS or ACK) 
-   * frames, other than the Block-Ack control frame, at the highest 
-   * rate in the BSSBasicRateSet parameter that is less than or equal 
-   * to the rate of the immediately previous frame in the frame 
-   * exchange sequence (as defined in 9.79.12) and that is of the
-   * same modulation type as the received frame. If no rate in the 
-   * basic rate set meets these conditions, then the control frame 
-   * sent in response to a received frame shall be transmitted at 
-   * the highest mandatory rate of the PHY that is less than or equal 
-   * to the rate of the received frame, and that is of the same 
-   * modulation type as the received frame. In addition, the Control 
-   * Response frame shall be sent using the same PHY options as the
-   * received frame, unless they conflict with the requirement to use 
-   * the BSSBasicRateSet parameter.
+   * The standard has relatively unambiguous rules for selecting a
+   * control response rate (the below is quoted from IEEE 802.11-2007,
+   * Section 9.6):
+   *
+   *   To allow the transmitting STA to calculate the contents of the
+   *   Duration/ID field, a STA responding to a received frame shall
+   *   transmit its Control Response frame (either CTS or ACK), other
+   *   than the BlockAck control frame, at the highest rate in the
+   *   BSSBasicRateSet parameter that is less than or equal to the
+   *   rate of the immediately previous frame in the frame exchange
+   *   sequence (as defined in 9.12) and that is of the same
+   *   modulation class (see 9.6.1) as the received frame...
    */
   WifiMode mode = GetDefaultMode ();
+  bool found = false;
 
   // First, search the BSS Basic Rate set
-  for (WifiRemoteStationManager::BasicModesIterator i = BeginBasicModes (); i != EndBasicModes (); i++)
+  for (WifiModeListIterator i = m_bssBasicRateSet.begin ();
+       i != m_bssBasicRateSet.end (); i++)
     {
-      if (i->GetPhyRate () > mode.GetPhyRate () &&
-          i->GetPhyRate () <= reqMode.GetPhyRate () &&
-          i->GetModulationClass () == reqMode.GetModulationClass ())
+      if ((!found || i->GetPhyRate () > mode.GetPhyRate ())
+          && i->GetPhyRate () <= reqMode.GetPhyRate ()
+          && i->GetModulationClass () == reqMode.GetModulationClass ())
         {
           mode = *i;
+          // We've found a potentially-suitable transmit rate, but we
+          // need to continue and consider all the basic rates before
+          // we can be sure we've got the right one.
+          found = true;
         }
     }
-  // no need to search Mandatory rate set because it is included
-  // within the Basic rate set.
+
+  // If we found a suitable rate in the BSSBasicRateSet, then we are
+  // done and can return that mode.
+  if (found)
+    {
+      return mode;
+    }
+
+  /**
+   * If no suitable basic rate was found, we search the mandatory
+   * rates. The standard (IEEE 802.11-2007, Section 9.6) says:
+   *
+   *   ...If no rate contained in the BSSBasicRateSet parameter meets
+   *   these conditions, then the control frame sent in response to a
+   *   received frame shall be transmitted at the highest mandatory
+   *   rate of the PHY that is less than or equal to the rate of the
+   *   received frame, and that is of the same modulation class as the
+   *   received frame. In addition, the Control Response frame shall
+   *   be sent using the same PHY options as the received frame,
+   *   unless they conflict with the requirement to use the
+   *   BSSBasicRateSet parameter.
+   *
+   * TODO: Note that we're ignoring the last sentence for now, because
+   * there is not yet any manipulation here of PHY options.
+   */
+  for (uint32_t idx = 0; idx < m_wifiPhy->GetNModes (); idx++)
+    {
+      WifiMode thismode = m_wifiPhy->GetMode (idx);
+
+      /* If the rate:
+       *
+       *  - is a mandatory rate for the PHY, and
+       *  - is equal to or faster than our current best choice, and
+       *  - is less than or equal to the rate of the received frame, and
+       *  - is of the same modulation class as the received frame
+       *
+       * ...then it's our best choice so far.
+       */
+      if (thismode.IsMandatory ()
+          && (!found || thismode.GetPhyRate () > mode.GetPhyRate ())
+          && thismode.GetPhyRate () <= reqMode.GetPhyRate ()
+          && thismode.GetModulationClass () == reqMode.GetModulationClass ())
+        {
+          mode = thismode;
+          // As above; we've found a potentially-suitable transmit
+          // rate, but we need to continue and consider all the
+          // mandatory rates before we can be sure we've got the right
+          // one.
+          found = true;
+        }
+    }
+
+  /**
+   * If we still haven't found a suitable rate for the response then
+   * someone has messed up the simulation config. This probably means
+   * that the WifiPhyStandard is not set correctly, or that a rate that
+   * is not supported by the PHY has been explicitly requested in a
+   * WifiRemoteStationManager (or descendant) configuration.
+   *
+   * Either way, it is serious - we can either disobey the standard or
+   * fail, and I have chosen to do the latter...
+   */
+  if (!found)
+    {
+      NS_FATAL_ERROR ("Can't find response rate for " << reqMode
+                      << ". Check standard and selected rates match.");
+    }
+
   return mode;
 }
 
@@ -602,7 +674,7 @@
   WifiRemoteStationState *state = new WifiRemoteStationState ();
   state->m_state = WifiRemoteStationState::BRAND_NEW;
   state->m_address = address;
-  state->m_modes.push_back (GetDefaultMode ());
+  state->m_operationalRateSet.push_back (GetDefaultMode ());
   const_cast<WifiRemoteStationManager *> (this)->m_states.push_back (state);
   return state;
 }
@@ -657,8 +729,8 @@
       delete (*i);
     }
   m_stations.clear ();
-  m_basicModes.clear ();
-  m_basicModes.push_back (m_defaultTxMode);
+  m_bssBasicRateSet.clear ();
+  m_bssBasicRateSet.push_back (m_defaultTxMode);
   NS_ASSERT (m_defaultTxMode.IsMandatory ());
 }
 void 
@@ -671,30 +743,19 @@
           return;
         }
     }
-  m_basicModes.push_back (mode);
+  m_bssBasicRateSet.push_back (mode);
 }
 uint32_t 
 WifiRemoteStationManager::GetNBasicModes (void) const
 {
-  return m_basicModes.size ();
+  return m_bssBasicRateSet.size ();
 }
 WifiMode 
 WifiRemoteStationManager::GetBasicMode (uint32_t i) const
 {
-  NS_ASSERT (i < m_basicModes.size ());
-  return m_basicModes[i];
+  NS_ASSERT (i < m_bssBasicRateSet.size ());
+  return m_bssBasicRateSet[i];
 }
-WifiRemoteStationManager::BasicModesIterator 
-WifiRemoteStationManager::BeginBasicModes (void) const
-{
-  return m_basicModes.begin ();
-}
-WifiRemoteStationManager::BasicModesIterator 
-WifiRemoteStationManager::EndBasicModes (void) const
-{
-  return m_basicModes.end ();
-}
-
 WifiMode
 WifiRemoteStationManager::GetNonUnicastMode (void) const
 {
@@ -737,12 +798,12 @@
 WifiRemoteStationManager::GetSupported (const WifiRemoteStation *station, uint32_t i) const
 {
   NS_ASSERT (i < GetNSupported (station));
-  return station->m_state->m_modes[i];
+  return station->m_state->m_operationalRateSet[i];
 }
 uint32_t 
 WifiRemoteStationManager::GetNSupported (const WifiRemoteStation *station) const
 {
-  return station->m_state->m_modes.size ();
+  return station->m_state->m_operationalRateSet.size ();
 }
 
 //WifiRemoteStationInfo constructor

--- a/src/devices/wifi/wifi-remote-station-manager.h	Wed Jun 23 06:43:21 2010 +0200
+++ b/src/devices/wifi/wifi-remote-station-manager.h	Wed Jun 23 08:47:29 2010 +0100
@@ -79,11 +79,7 @@
  */
 class WifiRemoteStationManager : public Object
 {
-private:
-  typedef std::vector<WifiMode> BasicModes;
 public:
-  typedef BasicModes::const_iterator BasicModesIterator;
-
   static TypeId GetTypeId (void);
 
   WifiRemoteStationManager ();
@@ -113,8 +109,6 @@
   WifiMode GetDefaultMode (void) const;
   uint32_t GetNBasicModes (void) const;
   WifiMode GetBasicMode (uint32_t i) const;
-  BasicModesIterator BeginBasicModes (void) const;
-  BasicModesIterator EndBasicModes (void) const;
 
   WifiMode GetNonUnicastMode (void) const;
 
@@ -405,8 +399,27 @@
 
   StationStates m_states;
   Stations m_stations;
+  /**
+   * This is a pointer to the WifiPhy associated with this
+   * WifiRemoteStationManager that is set on call to
+   * WifiRemoteStationManager::SetupPhy(). Through this pointer the
+   * station manager can determine PHY characteristics, such as the
+   * set of all transmission rates that may be supported (the
+   * "DeviceRateSet").
+   */
+  Ptr<WifiPhy> m_wifiPhy;
   WifiMode m_defaultTxMode;
-  BasicModes m_basicModes;
+
+  /**
+   * This member is the list of WifiMode objects that comprise the
+   * BSSBasicRateSet parameter. This list is constructed through calls
+   * to WifiRemoteStationManager::AddBasicMode(), and an API that
+   * allows external access to it is available through
+   * WifiRemoteStationManager::GetNBasicModes() and
+   * WifiRemoteStationManager::GetBasicMode().
+   */
+  WifiModeList m_bssBasicRateSet;
+
   bool m_isLowLatency;
   uint32_t m_maxSsrc;
   uint32_t m_maxSlrc;
@@ -437,7 +450,6 @@
 
 struct WifiRemoteStationState
 {
-  typedef std::vector<WifiMode> SupportedModes;
   enum 
     {
       BRAND_NEW,
@@ -445,7 +457,18 @@
       WAIT_ASSOC_TX_OK,
       GOT_ASSOC_TX_OK
     } m_state;
-  SupportedModes m_modes;
+
+  /**
+   * This member is the list of WifiMode objects that comprise the
+   * OperationalRateSet parameter for this remote station. This list
+   * is constructed through calls to
+   * WifiRemoteStationManager::AddSupportedMode(), and an API that
+   * allows external access to it is available through
+   * WifiRemoteStationManager::GetNSupported() and
+   * WifiRemoteStationManager::GetSupported().
+   */
+  WifiModeList m_operationalRateSet;
+
   Mac48Address m_address;
   WifiRemoteStationInfo m_info;
 };

--- a/src/devices/wifi/yans-wifi-phy.cc	Wed Jun 23 06:43:21 2010 +0200
+++ b/src/devices/wifi/yans-wifi-phy.cc	Wed Jun 23 08:47:29 2010 +0100
@@ -145,7 +145,7 @@
 {
   NS_LOG_FUNCTION (this);
   m_channel = 0;
-  m_modes.clear ();
+  m_deviceRateSet.clear ();
   m_device = 0;
   m_mobility = 0;
   m_state = 0;
@@ -516,12 +516,12 @@
 uint32_t 
 YansWifiPhy::GetNModes (void) const
 {
-  return m_modes.size ();
+  return m_deviceRateSet.size ();
 }
 WifiMode 
 YansWifiPhy::GetMode (uint32_t mode) const
 {
-  return m_modes[mode];
+  return m_deviceRateSet[mode];
 }
 uint32_t 
 YansWifiPhy::GetNTxPower (void) const
@@ -535,14 +535,14 @@
   NS_LOG_FUNCTION (this);
   m_channelStartingFrequency = 5e3; // 5.000 GHz 
 
-  m_modes.push_back (WifiPhy::GetOfdmRate6Mbps ());
-  m_modes.push_back (WifiPhy::GetOfdmRate9Mbps ());
-  m_modes.push_back (WifiPhy::GetOfdmRate12Mbps ());
-  m_modes.push_back (WifiPhy::GetOfdmRate18Mbps ());
-  m_modes.push_back (WifiPhy::GetOfdmRate24Mbps ());
-  m_modes.push_back (WifiPhy::GetOfdmRate36Mbps ());
-  m_modes.push_back (WifiPhy::GetOfdmRate48Mbps ());
-  m_modes.push_back (WifiPhy::GetOfdmRate54Mbps ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate6Mbps ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate9Mbps ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate12Mbps ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate18Mbps ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate24Mbps ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate36Mbps ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate48Mbps ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate54Mbps ());
 }
 
 
@@ -552,10 +552,10 @@
   NS_LOG_FUNCTION (this);
   m_channelStartingFrequency = 2412; // 2.412 GHz 
 
-  m_modes.push_back (WifiPhy::GetDsssRate1Mbps ());
-  m_modes.push_back (WifiPhy::GetDsssRate2Mbps ());
-  m_modes.push_back (WifiPhy::GetDsssRate5_5Mbps ());
-  m_modes.push_back (WifiPhy::GetDsssRate11Mbps ());
+  m_deviceRateSet.push_back (WifiPhy::GetDsssRate1Mbps ());
+  m_deviceRateSet.push_back (WifiPhy::GetDsssRate2Mbps ());
+  m_deviceRateSet.push_back (WifiPhy::GetDsssRate5_5Mbps ());
+  m_deviceRateSet.push_back (WifiPhy::GetDsssRate11Mbps ());
 }
 
 void
@@ -564,14 +564,14 @@
   NS_LOG_FUNCTION (this);
   m_channelStartingFrequency = 5e3; // 5.000 GHz, suppose 802.11a 
 
-  m_modes.push_back (WifiPhy::GetOfdmRate3MbpsBW10MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate4_5MbpsBW10MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate6MbpsBW10MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate9MbpsBW10MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate12MbpsBW10MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate18MbpsBW10MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate24MbpsBW10MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate27MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate3MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate4_5MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate6MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate9MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate12MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate18MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate24MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate27MbpsBW10MHz ());
 }
 
 void
@@ -580,14 +580,14 @@
   NS_LOG_FUNCTION (this); 
   m_channelStartingFrequency = 5e3; // 5.000 GHz, suppose 802.11a
 
-  m_modes.push_back (WifiPhy::GetOfdmRate1_5MbpsBW5MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate2_25MbpsBW5MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate3MbpsBW5MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate4_5MbpsBW5MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate6MbpsBW5MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate9MbpsBW5MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate12MbpsBW5MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate13_5MbpsBW5MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate1_5MbpsBW5MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate2_25MbpsBW5MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate3MbpsBW5MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate4_5MbpsBW5MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate6MbpsBW5MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate9MbpsBW5MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate12MbpsBW5MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate13_5MbpsBW5MHz ());
 }
 
 void
@@ -595,11 +595,11 @@
 {
   NS_LOG_FUNCTION (this);
   m_channelStartingFrequency = 5e3; // 5.000 GHz 
-  m_modes.push_back (WifiPhy::GetOfdmRate6Mbps ());
-  m_modes.push_back (WifiPhy::GetOfdmRate12Mbps ());
-  m_modes.push_back (WifiPhy::GetOfdmRate18Mbps ());
-  m_modes.push_back (WifiPhy::GetOfdmRate36Mbps ());
-  m_modes.push_back (WifiPhy::GetOfdmRate54Mbps ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate6Mbps ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate12Mbps ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate18Mbps ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate36Mbps ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate54Mbps ());
 }
 
 void
@@ -608,14 +608,14 @@
   NS_LOG_FUNCTION (this);
   m_channelStartingFrequency = 5e3; // 802.11p works over the 5Ghz freq range
 
-  m_modes.push_back (WifiPhy::GetOfdmRate3MbpsBW10MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate4_5MbpsBW10MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate6MbpsBW10MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate9MbpsBW10MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate12MbpsBW10MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate18MbpsBW10MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate24MbpsBW10MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate27MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate3MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate4_5MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate6MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate9MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate12MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate18MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate24MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate27MbpsBW10MHz ());
 }
 
 void
@@ -624,14 +624,14 @@
   NS_LOG_FUNCTION (this);
   m_channelStartingFrequency = 5e3; // 802.11p works over the 5Ghz freq range
 
-  m_modes.push_back (WifiPhy::GetOfdmRate3MbpsBW10MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate4_5MbpsBW10MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate6MbpsBW10MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate9MbpsBW10MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate12MbpsBW10MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate18MbpsBW10MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate24MbpsBW10MHz ());
-  m_modes.push_back (WifiPhy::GetOfdmRate27MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate3MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate4_5MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate6MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate9MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate12MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate18MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate24MbpsBW10MHz ());
+  m_deviceRateSet.push_back (WifiPhy::GetOfdmRate27MbpsBW10MHz ());
 }
 
 void 

--- a/src/devices/wifi/yans-wifi-phy.h	Wed Jun 23 06:43:21 2010 +0200
+++ b/src/devices/wifi/yans-wifi-phy.h	Wed Jun 23 08:47:29 2010 +0100
@@ -143,9 +143,6 @@
   virtual void ConfigureStandard (enum WifiPhyStandard standard);
 
 private:
-  typedef std::vector<WifiMode> Modes;
-
-private:
   YansWifiPhy (const YansWifiPhy &o);
   virtual void DoDispose (void);
   void Configure80211a (void);
@@ -176,7 +173,45 @@
   uint16_t m_channelNumber;
   Ptr<Object> m_device;
   Ptr<Object> m_mobility;
-  Modes m_modes;
+
+  /**
+   * This vector holds the set of transmission modes that this
+   * WifiPhy(-derived class) can support. In conversation we call this
+   * the DeviceRateSet (not a term you'll find in the standard), and
+   * it is a superset of standard-defined parameters such as the
+   * OperationalRateSet, and the BSSBasicRateSet (which, themselves,
+   * have a superset/subset relationship).
+   *
+   * Mandatory rates relevant to this WifiPhy can be found by
+   * iterating over this vector looking for WifiMode objects for which
+   * WifiMode::IsMandatory() is true.
+   *
+   * A quick note is appropriate here (well, here is as good a place
+   * as any I can find)...
+   *
+   * In the standard there is no text that explicitly precludes
+   * production of a device that does not support some rates that are
+   * mandatory (according to the standard) for PHYs that the device
+   * happens to fully or partially support.
+   *
+   * This approach is taken by some devices which choose to only support,
+   * for example, 6 and 9 Mbps ERP-OFDM rates for cost and power
+   * consumption reasons (i.e., these devices don't need to be designed
+   * for and waste current on the increased linearity requirement of
+   * higher-order constellations when 6 and 9 Mbps more than meet their
+   * data requirements). The wording of the standard allows such devices
+   * to have an OperationalRateSet which includes 6 and 9 Mbps ERP-OFDM
+   * rates, despite 12 and 24 Mbps being "mandatory" rates for the
+   * ERP-OFDM PHY.
+   *
+   * Now this doesn't actually have any impact on code, yet. It is,
+   * however, something that we need to keep in mind for the
+   * future. Basically, the key point is that we can't be making
+   * assumptions like "the Operational Rate Set will contain all the
+   * mandatory rates".
+   */
+  WifiModeList m_deviceRateSet;
+
   EventId m_endRxEvent;
   UniformVariable m_random;
   /// Standard-dependent center frequency of 0-th channel, MHz