--- a/src/devices/wifi/dca-txop.cc	Sun Jan 11 23:26:34 2009 +0000
+++ b/src/devices/wifi/dca-txop.cc	Mon Jan 12 13:35:41 2009 +0100
@@ -388,7 +388,7 @@
     }
   MacLowTransmissionParameters params;
   params.DisableOverrideDurationId ();
-  if (m_currentHdr.GetAddr1 ().IsBroadcast ()) 
+  if (m_currentHdr.GetAddr1 ().IsGroup ())
     {
       params.DisableRts ();
       params.DisableAck ();