In a wireless network with several AP using the same ssid and connected through a wired backbone, one AP sends packets to one of the STA associated with another AP (other bssid). Results in that the considered STA receives the packets twice.
Patch to apply to the example wifi-wired-bridging to reproduce the bug is following below.
Patch to correct the bug is attached (generated with Mercurial tool).

regards,
Charline Taibi Guguen
Technicolor

--- examples/wireless/wifi-wired-bridging.cc    2009-12-02 
11:03:34.793217000 +0100 
+++ scratch/my_wifi-wired-bridging.cc   2010-02-01 15:28:19.705864000 
+0100 
@@ -92,12 +92,19 @@ 
   YansWifiPhyHelper wifiPhy = YansWifiPhyHelper::Default (); 
   wifiPhy.SetPcapFormat 
(YansWifiPhyHelper::PCAP_FORMAT_80211_RADIOTAP); 


+  // calculate ssid for wifi subnetwork 
+  std::ostringstream oss; 
+  oss << "wifi-default-"; 
+  Ssid ssid = Ssid (oss.str ()); 
+ 
+  YansWifiChannelHelper wifiChannel = YansWifiChannelHelper::Default 
(); 
+  wifiPhy.SetChannel (wifiChannel.Create ()); 
+ 
+  Config::SetDefault 
("ns3::WifiRemoteStationManager::RtsCtsThreshold", StringValue 
("300")); 
+ 
+ 
   for (uint32_t i = 0; i < nWifis; ++i) 
     { 
-      // calculate ssid for wifi subnetwork 
-      std::ostringstream oss; 
-      oss << "wifi-default-" << i; 
-      Ssid ssid = Ssid (oss.str ()); 


       NodeContainer sta; 
       NetDeviceContainer staDev; 
@@ -108,8 +115,6 @@ 
       BridgeHelper bridge; 
       WifiHelper wifi = WifiHelper::Default (); 
       NqosWifiMacHelper wifiMac = NqosWifiMacHelper::Default (); 
-      YansWifiChannelHelper wifiChannel = 
YansWifiChannelHelper::Default (); 
-      wifiPhy.SetChannel (wifiChannel.Create ()); 


       sta.Create (nStas); 
       mobility.SetPositionAllocator ("ns3::GridPositionAllocator", 
@@ -164,7 +169,7 @@ 
   std::string protocol; 
   if (sendIp) 
     { 
-      dest = InetSocketAddress (staInterfaces[1].GetAddress (1), 
1025); 
+      dest = InetSocketAddress (staInterfaces[0].GetAddress (1), 
1025); 
       protocol = "ns3::UdpSocketFactory"; 
     } 
   else 
@@ -183,9 +188,35 @@ 
   ApplicationContainer apps = onoff.Install (staNodes[0].Get (0)); 
   apps.Start (Seconds (0.5)); 
   apps.Stop (Seconds (3.0)); 
+ 
+  //Create sink 
+  PacketSinkHelper packetSinkHelper (protocol, dest); 
+  ApplicationContainer appSinks = packetSinkHelper.Install (staNodes 
[0].Get(1)); 
+  appSinks.Start (Seconds (0.5)); 
+  appSinks.Stop (Seconds (3.0)); 
+ 


   wifiPhy.EnablePcap ("wifi-wired-bridging", apDevices[0]); 
   wifiPhy.EnablePcap ("wifi-wired-bridging", apDevices[1]); 
+  wifiPhy.EnablePcap ("wifi-wired-bridging", staDevices[0]); 
+ 
+  std::ofstream ofsAsciiWifi; 
+  ofsAsciiWifi.open ("wifi-wired-bridging-wifi-x-x.tr"); 
+  YansWifiPhyHelper::EnableAscii (ofsAsciiWifi, apDevices[0]); 
+  YansWifiPhyHelper::EnableAscii (ofsAsciiWifi, apDevices[1]); 
+  YansWifiPhyHelper::EnableAscii (ofsAsciiWifi, staDevices[0]); 
+ 
+//   std::ofstream ofsAsciiWifi2; 
+//   ofsAsciiWifi2.open ("wifi-wired-bridging-wifi-sta0--x-x.tr"); 
+//   YansWifiPhyHelper::EnableAscii (ofsAsciiWifi2, staDevices[0]); 
+//   std::ofstream ofsAsciiWifi3; 
+//   ofsAsciiWifi3.open ("wifi-wired-bridging-wifi-sta1--x-x.tr"); 
+//   YansWifiPhyHelper::EnableAscii (ofsAsciiWifi3, staDevices[0]); 
+ 
+  std::ofstream ofsAsciiCsma; 
+  ofsAsciiCsma.open ("wifi-wired-bridging-csma--x-x.tr"); 
+  CsmaHelper::EnableAscii (ofsAsciiCsma, backboneDevices); 
+ 


   std::ofstream os; 
   os.open ("wifi-wired-bridging.mob");