diff -r cf0348c84652 -r bfe1b44645d8 src/csma/helper/csma-helper.h
--- a/src/csma/helper/csma-helper.h	Mon Aug 13 15:59:14 2012 -0700
+++ b/src/csma/helper/csma-helper.h	Tue Aug 14 09:12:05 2012 -0700
@@ -192,6 +192,19 @@
    */
   NetDeviceContainer Install (const NodeContainer &c, std::string channelName) const;
 
+  /**
+  * 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. The Install() method should have previously been
+  * called by the user.
+  *
+  * \param c NetDeviceContainer of the set of net devices for which the 
+  *          CsmaNetDevice should be modified to use a fixed stream
+  * \param stream first stream index to use
+  * \return the number of stream indices assigned by this helper
+  */
+  int64_t AssignStreams (NetDeviceContainer c, int64_t stream);
+
 private:
   /*
    * \internal