--- a/src/devices/csma-cd/csma-cd-net-device.h	Tue Jul 31 11:42:25 2007 +0200
+++ b/src/devices/csma-cd/csma-cd-net-device.h	Wed Aug 01 08:58:18 2007 +0200
@@ -173,7 +173,7 @@
    * @see CsmaCdChannel
    * \param p a reference to the received packet
    */
-  void Receive (Packet& p);
+  void Receive (const Packet& p);
 
   bool IsSendEnabled (void);
   bool IsReceiveEnabled (void);