diff -r 7fdad61b88f1 -r 8f1a53d3f6ca src/wifi/model/cara-wifi-manager.cc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/wifi/model/cara-wifi-manager.cc	Fri Mar 04 01:26:54 2011 +0000
@@ -0,0 +1,180 @@
+/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2004,2005,2006 INRIA
+ *
+ * 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: Federico Maguolo <maguolof@dei.unipd.it>
+ */
+
+#include "cara-wifi-manager.h"
+#include "ns3/assert.h"
+#include "ns3/log.h"
+#include "ns3/double.h"
+#include "ns3/uinteger.h"
+#include "ns3/simulator.h"
+
+NS_LOG_COMPONENT_DEFINE ("Cara");
+
+
+namespace ns3 {
+
+struct CaraWifiRemoteStation : public WifiRemoteStation
+{
+  uint32_t m_timer;
+  uint32_t m_success;
+  uint32_t m_failed;  
+  uint32_t m_rate;
+};
+
+NS_OBJECT_ENSURE_REGISTERED(CaraWifiManager);
+
+TypeId 
+CaraWifiManager::GetTypeId (void)
+{
+ static TypeId tid = TypeId ("ns3::CaraWifiManager")
+   .SetParent<WifiRemoteStationManager> ()
+   .AddConstructor<CaraWifiManager> ()
+   .AddAttribute ("ProbeThreshold",
+                  "The number of consecutive transmissions failure to activate the RTS probe.",
+                  UintegerValue (1),
+                  MakeUintegerAccessor (&CaraWifiManager::m_probeThreshold),
+                  MakeUintegerChecker<uint32_t> ())
+   .AddAttribute ("FailureThreshold",
+                  "The number of consecutive transmissions failure to decrease the rate.",
+                  UintegerValue (2),
+                  MakeUintegerAccessor (&CaraWifiManager::m_failureThreshold),
+                  MakeUintegerChecker<uint32_t> ())
+   .AddAttribute ("SuccessThreshold",
+                  "The minimum number of sucessfull transmissions to try a new rate.",
+                  UintegerValue (10),
+                  MakeUintegerAccessor (&CaraWifiManager::m_successThreshold),
+                  MakeUintegerChecker<uint32_t> ())
+   .AddAttribute ("Timeout",
+                  "The 'timer' in the CARA algorithm",
+                  UintegerValue (15),
+                  MakeUintegerAccessor (&CaraWifiManager::m_timerTimeout),
+                  MakeUintegerChecker<uint32_t> ())
+ ;
+ return tid;
+}
+
+CaraWifiManager::CaraWifiManager ()
+  : WifiRemoteStationManager ()
+{}
+CaraWifiManager::~CaraWifiManager ()
+{}
+
+WifiRemoteStation *
+CaraWifiManager::DoCreateStation (void) const
+{
+  CaraWifiRemoteStation *station = new CaraWifiRemoteStation ();
+  station->m_rate = 0;
+  station->m_success = 0;
+  station->m_failed = 0;
+  station->m_timer = 0;
+  return station;
+}
+
+void 
+CaraWifiManager::DoReportRtsFailed (WifiRemoteStation *st)
+{}
+
+void 
+CaraWifiManager::DoReportDataFailed (WifiRemoteStation *st)
+{
+  CaraWifiRemoteStation *station = (CaraWifiRemoteStation *) st;
+  NS_LOG_FUNCTION (station);
+  station->m_timer++;
+  station->m_failed++;
+  station->m_success = 0;
+  if (station->m_failed >= m_failureThreshold) 
+    {
+      NS_LOG_DEBUG ("self="<<station<<" dec rate");
+      if (station->m_rate != 0)
+        {
+          station->m_rate--;
+        }
+      station->m_failed = 0;
+      station->m_timer = 0;
+    }
+}
+void 
+CaraWifiManager::DoReportRxOk (WifiRemoteStation *st,
+                                     double rxSnr, WifiMode txMode)
+{}
+void 
+CaraWifiManager::DoReportRtsOk (WifiRemoteStation *st,
+                                      double ctsSnr, WifiMode ctsMode, double rtsSnr)
+{
+  NS_LOG_DEBUG ("self="<<st<<" rts ok");
+}
+void 
+CaraWifiManager::DoReportDataOk (WifiRemoteStation *st,
+                                       double ackSnr, WifiMode ackMode, double dataSnr)
+{
+  CaraWifiRemoteStation *station = (CaraWifiRemoteStation *) st;
+  station->m_timer++;
+  station->m_success++;
+  station->m_failed = 0;
+  NS_LOG_DEBUG ("self="<<station<<" data ok success="<<station->m_success<<", timer="<<station->m_timer);
+  if ((station->m_success == m_successThreshold ||
+       station->m_timer >= m_timerTimeout))
+    {
+      if (station->m_rate < GetNSupported (station) - 1)
+        {
+          station->m_rate++;
+        }
+      NS_LOG_DEBUG ("self="<<station<<" inc rate=" << station->m_rate);
+      station->m_timer = 0;
+      station->m_success = 0;
+    }
+}
+void 
+CaraWifiManager::DoReportFinalRtsFailed (WifiRemoteStation *st)
+{}
+void 
+CaraWifiManager::DoReportFinalDataFailed (WifiRemoteStation *st)
+{}
+
+WifiMode
+CaraWifiManager::DoGetDataMode (WifiRemoteStation *st,
+                                      uint32_t size)
+{
+  CaraWifiRemoteStation *station = (CaraWifiRemoteStation *) st;
+  return GetSupported (station, station->m_rate);
+}
+WifiMode
+CaraWifiManager::DoGetRtsMode (WifiRemoteStation *st)
+{
+  // XXX: we could/should implement the Arf algorithm for
+  // RTS only by picking a single rate within the BasicRateSet.
+  return GetSupported (st, 0);
+}
+
+bool
+CaraWifiManager::DoNeedRts (WifiRemoteStation *st,
+                                  Ptr<const Packet> packet, bool normally)
+{
+  CaraWifiRemoteStation *station = (CaraWifiRemoteStation *) st;
+  return normally || station->m_failed >= m_probeThreshold;
+}
+
+bool 
+CaraWifiManager::IsLowLatency (void) const
+{
+  return true;
+}
+
+} // namespace ns3