diff --git a/src/devices/wifi/mac-low.cc b/src/devices/wifi/mac-low.cc
index 30fda0099..55cd885f2 100644
--- a/src/devices/wifi/mac-low.cc
+++ b/src/devices/wifi/mac-low.cc
@@ -804,7 +804,7 @@ MacLow::DoNavResetNow (Time duration)
       (*i)->NavReset (duration);
     }
   m_lastNavStart = Simulator::Now ();
-  m_lastNavStart = duration;
+  m_lastNavDuration = duration;
 }
 bool
 MacLow::DoNavStartNow (Time duration)