How do I go about making the Queue in the MAC layer of wifi devices a Last Come First Served (LIFO) from the default FIFO order?

[Boong Baang]

The attribute to directly change the queue to DROP_OLDEST to DROP_NEWEST exists which becomes a LIFO for a queue size of 1, but I was not able to find a general way of making the queue into an LIFO from the default settings.

  Config::Set ("/NodeList/*/DeviceList/*/$ns3::WifiNetDevice/Mac/$ns3::RegularWifiMac/$ns3::OcbWifiMac/Txop/Queue/MaxSize", StringValue ("1p"));
  Config::Set ("/NodeList/*/DeviceList/*/$ns3::WifiNetDevice/Mac/$ns3::RegularWifiMac/$ns3::OcbWifiMac/Txop/Queue/DropPolicy", StringValue("DropOldest"));
  Config::Set ("/NodeList/*/$ns3::Node/DeviceList/*/$ns3::WifiNetDevice/Mac/$ns3::OcbWifiMac/Txop/$ns3::Txop/Queue/$ns3::WifiMacQueue/MaxSize", StringValue ("1p"));
  Config::Set ("/NodeList/*/$ns3::Node/DeviceList/*/$ns3::WifiNetDevice/Mac/$ns3::OcbWifiMac/Txop/$ns3::Txop/Queue/$ns3::WifiMacQueue/DropPolicy", StringValue("DropOldest"));

Any help in that direction will be greatly appreciated.

[Avik Dutta]

I think  for your purpose you have to make change in the mac_low.cc 

[Boong Baang]

Both for the LIFO and DropOldest ? 

DropOldest can be set directly, and I was thinking if the queue object can be changed to a stack like behavior, I can have LIFO but I am unable to figure out where the modification can be done.