--- a/src/devices/csma/csma-net-device.h	Tue Aug 28 13:14:43 2007 +0200
+++ b/src/devices/csma/csma-net-device.h	Tue Aug 28 14:10:54 2007 +0200
@@ -423,8 +423,8 @@
    * @see class CallBackTraceSource
    * @see class TraceResolver
    */
-  CallbackTraceSource<Packet &> m_rxTrace;
-  CallbackTraceSource<Packet &> m_dropTrace;
+  CallbackTraceSource<const Packet &> m_rxTrace;
+  CallbackTraceSource<const Packet &> m_dropTrace;
 
 };