diff --git a/include/AuthManagerDriver.h b/include/AuthManagerDriver.h
index 723f24d9f3..f018808ba6 100644
--- a/include/AuthManagerDriver.h
+++ b/include/AuthManagerDriver.h
@@ -50,8 +50,7 @@ public:
      *  Implements the VM Manager driver protocol.
      *    @param message the string read from the driver
      */
-    void protocol(
-        string&     message);
+    void protocol(const string& message) const;
 
     /**
      *  Re-starts the driver
diff --git a/include/HookManagerDriver.h b/include/HookManagerDriver.h
index 164eff6670..af0d8c6fef 100644
--- a/include/HookManagerDriver.h
+++ b/include/HookManagerDriver.h
@@ -29,7 +29,7 @@ using namespace std;
 /**
  *  HookManagerDriver provides a base class to implement Hook (Execution)
  *  Drivers. This class implements the protocol and recover functions
- *  from the Mad interface. This class may be used to further specialize 
+ *  from the Mad interface. This class may be used to further specialize
  *  the Execution driver.
  */
 class HookManagerDriver : public Mad
@@ -49,14 +49,13 @@ public:
      *  Implements the Hook driver protocol.
      *    @param message the string read from the driver
      */
-    void protocol(
-        string&     message);
+    void protocol(const string& message) const;
 
     /**
      *  TODO: What do we need here? just poll the Hosts to recover..
      */
     void recover();
-	
+
 	/**<id> <hook_name> <LOCAL|host> <script> <args|->
      *  Sends an execution request to the MAD: "EXECUTE id name local cmd args"
      *    @param oid the virtual machine id.
@@ -88,7 +87,7 @@ public:
 private:
 
     friend class            HookManager;
-    
+
     VirtualMachinePool *    vmpool;
 };
 
diff --git a/include/ImageManagerDriver.h b/include/ImageManagerDriver.h
index 785f08029a..155b6cc47f 100644
--- a/include/ImageManagerDriver.h
+++ b/include/ImageManagerDriver.h
@@ -30,16 +30,16 @@ class ImagePool;
 class ImageManager;
 
 /**
- *  ImageManagerDriver represents the basic abstraction for Image Repository 
- *  drivers. It implements the protocol and recover functions from the Mad 
+ *  ImageManagerDriver represents the basic abstraction for Image Repository
+ *  drivers. It implements the protocol and recover functions from the Mad
  *  interface.
  */
 class ImageManagerDriver : public Mad
 {
 public:
 
-    ImageManagerDriver(int        userid, 
-                       const      map<string,string>& attrs, 
+    ImageManagerDriver(int        userid,
+                       const      map<string,string>& attrs,
                        bool       sudo,
                        ImagePool* _ipool):
             Mad(userid,attrs,sudo),ipool(_ipool){};
@@ -50,7 +50,7 @@ public:
      *  Implements the Image Manager driver protocol.
      *    @param message the string read from the driver
      */
-    void protocol(string& message);
+    void protocol(const string& message) const;
 
     /**
      *  TODO: What do we need here? Check on-going xfr?
diff --git a/include/InformationManagerDriver.h b/include/InformationManagerDriver.h
index 91b0c3e8dd..3d7593a234 100644
--- a/include/InformationManagerDriver.h
+++ b/include/InformationManagerDriver.h
@@ -50,7 +50,7 @@ public:
      *  Implements the IM driver protocol.
      *    @param message the string read from the driver
      */
-    void protocol(string& message);
+    void protocol(const string& message) const;
 
     /**
      *  TODO: What do we need here? just poll the Hosts to recover..
diff --git a/include/Mad.h b/include/Mad.h
index 79188ab2fb..c8eb987d9e 100644
--- a/include/Mad.h
+++ b/include/Mad.h
@@ -32,17 +32,17 @@ using namespace std;
 
 /**
  * Base class to build specific middleware access drivers (MAD).
- * This class provides generic MAD functionality. 
+ * This class provides generic MAD functionality.
  */
 class Mad
 {
 protected:
     /**
-     *  The constructor initialize the class members but DOES NOT start the 
+     *  The constructor initialize the class members but DOES NOT start the
      *  driver. A subsequent call to the start() method is needed.
      *    @param userid user running this MAD
      *    @param attrs configuration attributes for the driver
-     *    @param sudo the driver is started through sudo if true 
+     *    @param sudo the driver is started through sudo if true
      */
     Mad(
         int userid,
@@ -53,13 +53,13 @@ protected:
             sudo_execution(sudo),
             pid(-1)
     {};
-    
+
     /**
      *  The destructor of the class finalizes the driver process, and all its
      *  associated resources (i.e. pipes)
      */
     virtual ~Mad();
-    
+
     /**
      *  Send a command to the driver
      *    @param os an output string stream with the message, it must be
@@ -70,7 +70,7 @@ protected:
     {
         string        str;
         const char *  cstr;
-        
+
         str  = os.str();
         cstr = str.c_str();
 
@@ -95,7 +95,7 @@ protected:
      *    @param first character of the type string
      *    @return the message type
      */
-    Log::MessageType log_type(const char r)
+    Log::MessageType log_type(const char r) const
     {
         Log::MessageType lt;
 
@@ -121,17 +121,17 @@ private:
     friend class MadManager;
 
     /**
-     *  Communication pipe file descriptor. Represents the MAD to nebula 
+     *  Communication pipe file descriptor. Represents the MAD to nebula
      *  communication stream (nebula<-mad)
      */
     int                 mad_nebula_pipe;
 
     /**
-     *  Communication pipe file descriptor. Represents the nebula to MAD 
+     *  Communication pipe file descriptor. Represents the nebula to MAD
      *  communication stream (nebula->mad)
      */
     int                 nebula_mad_pipe;
-        
+
     /**
      *  User running this MAD as defined in the upool DB
      */
@@ -144,7 +144,7 @@ private:
     map<string,string>  attributes;
 
     /**
-     *  True if the mad is to be executed through sudo, with the identity of the 
+     *  True if the mad is to be executed through sudo, with the identity of the
      *  Mad owner (uid).
      */
     bool                sudo_execution;
@@ -153,16 +153,16 @@ private:
      *  Process ID of the running MAD.
      */
     pid_t               pid;
-    
+
     /**
-     *  Starts the MAD. This function creates a new process, sets up the 
+     *  Starts the MAD. This function creates a new process, sets up the
      *  communication pipes and sends the initialization command to the driver.
      *    @return 0 on success
      */
     int start();
 
     /**
-     *  Reloads the driver: sends the finalize command, "waits" for the 
+     *  Reloads the driver: sends the finalize command, "waits" for the
      *  driver process and closes the communication pipes. Then the driver is
      *  started again by calling the start() function
      *    @return 0 on success
@@ -174,14 +174,13 @@ private:
      *  actions on the associated manager.
      *    @param message the string read from the driver
      */
-    virtual void protocol(
-        string&     message) = 0;
+    virtual void protocol(const string& message) const = 0;
 
     /**
      *  This function is called whenever the driver crashes. This function
      *  should perform the actions needed to recover the VMs.
      */
-    virtual void recover() = 0;    
+    virtual void recover() = 0;
 };
 
 #endif /*MAD_H_*/
diff --git a/include/TransferManagerDriver.h b/include/TransferManagerDriver.h
index beb0be2836..97e3f28726 100644
--- a/include/TransferManagerDriver.h
+++ b/include/TransferManagerDriver.h
@@ -48,8 +48,7 @@ public:
      *  Implements the VM Manager driver protocol.
      *    @param message the string read from the driver
      */
-    void protocol(
-        string&     message);
+    void protocol(const string& message) const;
 
     /**
      *  TODO: What do we need here? Check on-going xfr?
diff --git a/include/VirtualMachineManagerDriver.h b/include/VirtualMachineManagerDriver.h
index 5be093aa76..0fa295d622 100644
--- a/include/VirtualMachineManagerDriver.h
+++ b/include/VirtualMachineManagerDriver.h
@@ -49,8 +49,7 @@ public:
      *  Implements the VM Manager driver protocol.
      *    @param message the string read from the driver
      */
-    void protocol(
-        string&     message);
+    void protocol(const string& message) const;
 
     /**
      *  TODO: What do we need here? just poll the active VMs to recover
diff --git a/src/authm/AuthManagerDriver.cc b/src/authm/AuthManagerDriver.cc
index d4b4b93b5f..b270e9ddbc 100644
--- a/src/authm/AuthManagerDriver.cc
+++ b/src/authm/AuthManagerDriver.cc
@@ -25,9 +25,9 @@
 /* Driver ASCII Protocol Implementation                                       */
 /* ************************************************************************** */
 
-void AuthManagerDriver::authorize(int           oid, 
-                                  int           uid, 
-                                  const string& reqs, 
+void AuthManagerDriver::authorize(int           oid,
+                                  int           uid,
+                                  const string& reqs,
                                   bool          acl) const
 {
     ostringstream os;
@@ -60,8 +60,7 @@ void AuthManagerDriver::authenticate(int           oid,
 /* MAD Interface                                                              */
 /* ************************************************************************** */
 
-void AuthManagerDriver::protocol(
-    string&     message)
+void AuthManagerDriver::protocol(const string& message) const
 {
     istringstream is(message);
     ostringstream os;
diff --git a/src/hm/HookManagerDriver.cc b/src/hm/HookManagerDriver.cc
index 9f49ba55ea..a38ec0f76f 100644
--- a/src/hm/HookManagerDriver.cc
+++ b/src/hm/HookManagerDriver.cc
@@ -29,9 +29,9 @@ void HookManagerDriver::execute(
         const string&   arguments ) const
 {
     ostringstream oss;
-    
+
     oss << "EXECUTE " << oid << " " << hook_name << " LOCAL " << command << " ";
-    
+
     if ( arguments.empty() )
     {
         oss << "-" << endl;
@@ -55,10 +55,10 @@ void HookManagerDriver::execute(
         const string&   arguments ) const
 {
     ostringstream oss;
-    
-    oss << "EXECUTE " << oid << " " << hook_name << " " << host_name << " " 
+
+    oss << "EXECUTE " << oid << " " << hook_name << " " << host_name << " "
         << command << " ";
-    
+
     if ( arguments.empty() )
     {
         oss << "-" << endl;
@@ -74,10 +74,9 @@ void HookManagerDriver::execute(
 /* -------------------------------------------------------------------------- */
 /* -------------------------------------------------------------------------- */
 
-void HookManagerDriver::protocol(
-    string&     message)
-{       
-    istringstream   is(message);   
+void HookManagerDriver::protocol(const string& message) const
+{
+    istringstream   is(message);
     //stores the action name
     string          action;
     //stores the action result
@@ -88,7 +87,7 @@ void HookManagerDriver::protocol(
     ostringstream    os;
     string           hinfo;
     VirtualMachine * vm;
-    
+
     // Parse the driver message
 
     os << "Message received: " << message;
@@ -109,7 +108,7 @@ void HookManagerDriver::protocol(
         is >> result >> ws;
     }
     else
-    {    
+    {
         return;
     }
 
@@ -135,49 +134,49 @@ void HookManagerDriver::protocol(
     {
         return;
     }
-           
+
     vm = vmpool->get(id,true);
-        
+
     if ( vm == 0 )
     {
         return;
     }
-        
+
     // -------------------------------------------------------------------------
     // Protocol implementation
     // -------------------------------------------------------------------------
-    
+
     if ( action == "EXECUTE" )
     {
         ostringstream oss;
-        
+
         string hook_name;
         string info;
-        
+
         if ( is.good() )
         {
             getline(is,hook_name);
         }
-        
+
         getline (is,info);
-        
+
         if (result == "SUCCESS")
-        {   
+        {
             oss << "Success executing Hook: " << hook_name << ". " << info;
             vm->log("HKM",Log::INFO,oss);
         }
         else
         {
             oss << "Error executing Hook: " << hook_name << ". " << info;
-           
+
             if ( !info.empty() && info[0] != '-' )
-            { 
+            {
                 vm->set_template_error_message(oss.str());
                 vmpool->update(vm);
             }
 
             vm->log("HKM",Log::ERROR,oss);
-        }        
+        }
     }
     else if (action == "LOG")
     {
@@ -186,9 +185,9 @@ void HookManagerDriver::protocol(
         getline(is,info);
         vm->log("HKM",log_type(result[0]),info.c_str());
     }
-    
+
     vm->unlock();
-    
+
     return;
 }
 
@@ -198,5 +197,5 @@ void HookManagerDriver::protocol(
 void HookManagerDriver::recover()
 {
     NebulaLog::log("HKM", Log::ERROR, "Hook driver crashed, recovering...");
- 
+
 }
diff --git a/src/im/InformationManagerDriver.cc b/src/im/InformationManagerDriver.cc
index fdd60e58f4..d79939444c 100644
--- a/src/im/InformationManagerDriver.cc
+++ b/src/im/InformationManagerDriver.cc
@@ -40,8 +40,7 @@ void InformationManagerDriver::monitor(int           oid,
 /* -------------------------------------------------------------------------- */
 /* -------------------------------------------------------------------------- */
 
-void InformationManagerDriver::protocol(
-    string&     message)
+void InformationManagerDriver::protocol(const string& message) const
 {
     istringstream   is(message);
     //stores the action name
diff --git a/src/image/ImageManagerDriver.cc b/src/image/ImageManagerDriver.cc
index 106df48661..8f7074d939 100644
--- a/src/image/ImageManagerDriver.cc
+++ b/src/image/ImageManagerDriver.cc
@@ -555,8 +555,7 @@ error:
 /* -------------------------------------------------------------------------- */
 /* -------------------------------------------------------------------------- */
 
-void ImageManagerDriver::protocol(
-    string&     message)
+void ImageManagerDriver::protocol(const string& message) const
 {
     istringstream is(message);
     ostringstream oss;
diff --git a/src/tm/TransferManagerDriver.cc b/src/tm/TransferManagerDriver.cc
index 58c4ddf369..6b01d2a889 100644
--- a/src/tm/TransferManagerDriver.cc
+++ b/src/tm/TransferManagerDriver.cc
@@ -41,8 +41,7 @@ void TransferManagerDriver::transfer (
 /* MAD Interface                                                              */
 /* ************************************************************************** */
 
-void TransferManagerDriver::protocol(
-    string&     message)
+void TransferManagerDriver::protocol(const string& message) const
 {
     istringstream           is(message);
     ostringstream           os;
diff --git a/src/vmm/VirtualMachineManagerDriver.cc b/src/vmm/VirtualMachineManagerDriver.cc
index a1dd2c7a2c..7a9b0ca82e 100644
--- a/src/vmm/VirtualMachineManagerDriver.cc
+++ b/src/vmm/VirtualMachineManagerDriver.cc
@@ -179,8 +179,7 @@ static void log_monitor_error(VirtualMachine* vm,
 /* -------------------------------------------------------------------------- */
 /* -------------------------------------------------------------------------- */
 
-void VirtualMachineManagerDriver::protocol(
-    string&     message)
+void VirtualMachineManagerDriver::protocol(const string& message) const
 {
     istringstream is(message);
     ostringstream os;