--- a/src/wifi/model/edca-txop-n.h	Tue Aug 14 13:12:00 2012 -0700
+++ b/src/wifi/model/edca-txop-n.h	Tue Aug 14 13:52:17 2012 -0700
@@ -150,6 +150,16 @@
   void SetBlockAckInactivityTimeout (uint16_t timeout);
   void SendDelbaFrame (Mac48Address addr, uint8_t tid, bool byOriginator);
 
+ /**
+  * Assign a fixed random variable stream number to the random variables
+  * used by this model.  Return the number of streams (possibly zero) that
+  * have been assigned.
+  *
+  * \param stream first stream index to use
+  * \return the number of stream indices assigned by this model
+  */
+  int64_t AssignStreams (int64_t stream);
+
 private:
   void DoStart ();
   /**