--- a/src/devices/wifi/mac-low.cc	Fri Dec 07 09:51:59 2007 +0100
+++ b/src/devices/wifi/mac-low.cc	Fri Dec 07 10:06:29 2007 +0100
@@ -946,7 +946,7 @@
 bool 
 MacLow::IsNavZero (void) const
 {
-  if (m_lastNavStart + m_lastNavDuration > Simulator::Now ()) 
+  if (m_lastNavStart + m_lastNavDuration < Simulator::Now ()) 
     {
       return true;
     }