--- a/src/csma/examples/csma-ping.cc	Mon Aug 13 10:46:09 2012 -0700
+++ b/src/csma/examples/csma-ping.cc	Mon Aug 13 16:08:13 2012 -0700
@@ -83,8 +83,8 @@
   Config::SetDefault ("ns3::Ipv4RawSocketImpl::Protocol", StringValue ("2"));
   InetSocketAddress dst = InetSocketAddress (addresses.GetAddress (3));
   OnOffHelper onoff = OnOffHelper ("ns3::Ipv4RawSocketFactory", dst);
-  onoff.SetAttribute ("OnTime", RandomVariableValue (ConstantVariable (1.0)));
-  onoff.SetAttribute ("OffTime", RandomVariableValue (ConstantVariable (0.0)));
+  onoff.SetAttribute ("OnTime", StringValue ("ns3::ConstantRandomVariable[Constant=1]"));
+  onoff.SetAttribute ("OffTime", StringValue ("ns3::ConstantRandomVariable[Constant=0]"));
   onoff.SetAttribute ("DataRate", DataRateValue (DataRate (15000)));
   onoff.SetAttribute ("PacketSize", UintegerValue (1200));