diff --git a/arch/x86/include/asm/iRCCE.h b/arch/x86/include/asm/iRCCE.h
index 8b878bfd..5c0edfc3 100644
--- a/arch/x86/include/asm/iRCCE.h
+++ b/arch/x86/include/asm/iRCCE.h
@@ -30,12 +30,29 @@
 #ifndef IRCCE_H
 #define IRCCE_H
 
-#include <asm/RCCE.h>
+#include "RCCE.h"
 
 #define iRCCE_SUCCESS  RCCE_SUCCESS
-#define iRCCE_PENDING      -1
-#define iRCCE_RESERVED     -2
-#define iRCCE_NOT_ENQUEUED -3
+#define iRCCE_PENDING       -1
+#define iRCCE_RESERVED      -2
+#define iRCCE_NOT_ENQUEUED  -3
+
+#define iRCCE_ANY_SOURCE    -1
+
+#define iRCCE_PRIOS			 5
+#define iRCCE_MAILBOX_EMPTY 		-2
+#define iRCCE_LAST_MAILS_NOT_RECV 	-3
+#define iRCCE_MAILBOX_ALL 	 	-4
+#define iRCCE_MAILBOX_OPEN		 0
+#define iRCCE_MAILBOX_CLOSED		 1
+
+// iRCCE-mailbox-system tags
+#define iRCCE_LAST_MAIL			-1
+#define iRCCE_ANYLENGTH			-2
+#define iRCCE_ANYLENGTH_PIGGYBACK	-3
+
+
+typedef volatile char iRCCE_SHORT_FLAG;
 
 typedef struct _iRCCE_SEND_REQUEST {
   char *privbuf;    // source buffer in local private memory (send buffer)
@@ -94,15 +111,32 @@ typedef struct _iRCCE_WAIT_LIST {
 } iRCCE_WAIT_LIST;
 
 
+#define iRCCE_MAIL_HEADER_PAYLOAD 13
+typedef struct _iRCCE_MAIL_HEADER {
+	int source;			// UE that will send the header
+	size_t size;			// size of the message which will be send/received
+	int tag;			// tag indicating which kind of message we have
+	struct _iRCCE_MAIL_HEADER* next;// pointer for queue  -  could be replaced by list-object
+	char prio; 	 	 	// priority of the mail
+	iRCCE_SHORT_FLAG sent;		// flag indicating that header is new
+	iRCCE_SHORT_FLAG closed; 	// flag indication that mailbox is closed
+	char payload[iRCCE_MAIL_HEADER_PAYLOAD]; // payload for small messages
+} iRCCE_MAIL_HEADER;
+
+typedef struct _iRCCE_MAIL_TRASH_BIN {
+	iRCCE_MAIL_HEADER* first;
+	iRCCE_MAIL_HEADER* last;
+} iRCCE_MAIL_TRASH_BIN;
+
 ///////////////////////////////////////////////////////////////
 //
 //                       THE iRCCE API:
 //
-//  Initialize function:
+//  Initialize/Finalize functions:
 int   iRCCE_init(void);
 //
 //  Non-blocking send/recv functions:
-int   iRCCE_isend(char *, size_t, int, iRCCE_SEND_REQUEST *);
+int   iRCCE_isend(char *, ssize_t, int, iRCCE_SEND_REQUEST *);
 int   iRCCE_isend_test(iRCCE_SEND_REQUEST *, int *);
 int   iRCCE_isend_wait(iRCCE_SEND_REQUEST *);
 int   iRCCE_isend_push(void);
@@ -133,6 +167,18 @@ int   iRCCE_wait_any(iRCCE_WAIT_LIST*, iRCCE_SEND_REQUEST **, iRCCE_RECV_REQUEST
 int   iRCCE_isend_cancel(iRCCE_SEND_REQUEST *, int *);
 int   iRCCE_irecv_cancel(iRCCE_RECV_REQUEST *, int *);
 //
+//  Blocking send/recv functions for mailbox system
+int iRCCE_mail_send(size_t, int, char, char*, int);
+int iRCCE_mail_recv(iRCCE_MAIL_HEADER**);
+//
+// functions to empty mailbox-queue and to check for last mails:
+int iRCCE_mail_release(iRCCE_MAIL_HEADER**);
+int iRCCE_last_mail_recv(void);
+int iRCCE_mailbox_wait(void); 
+int iRCCE_mailbox_flush(void);
+int iRCCE_mailbox_close(int);
+void iRCCE_mailbox_print_header(iRCCE_MAIL_HEADER*);
+//
 ///////////////////////////////////////////////////////////////
 //
 //      Just for for convenience:
diff --git a/arch/x86/include/asm/iRCCE_lib.h b/arch/x86/include/asm/iRCCE_lib.h
index 0d8b4e16..372b9cdd 100644
--- a/arch/x86/include/asm/iRCCE_lib.h
+++ b/arch/x86/include/asm/iRCCE_lib.h
@@ -29,6 +29,23 @@
 
 extern iRCCE_SEND_REQUEST* iRCCE_isend_queue;
 extern iRCCE_RECV_REQUEST* iRCCE_irecv_queue[RCCE_MAXNP];
+extern iRCCE_RECV_REQUEST* iRCCE_irecv_any_source_queue;
+
+// pointer to MPB-mailbox-space
+extern volatile iRCCE_MAIL_HEADER* iRCCE_mailbox_send[RCCE_MAXNP];
+extern volatile iRCCE_MAIL_HEADER* iRCCE_mailbox_recv[RCCE_MAXNP];
+
+// queue for received headers
+extern iRCCE_MAIL_HEADER* iRCCE_mailbox_recv_queue[iRCCE_PRIOS];
+
+// flags for last mail
+extern iRCCE_SHORT_FLAG iRCCE_last_mail[RCCE_MAXNP]; 
+
+// field to store open/closed status of mailboxes
+extern iRCCE_SHORT_FLAG iRCCE_mailbox_status[RCCE_MAXNP];
+
+// garbage collection for mailbox
+extern iRCCE_MAIL_TRASH_BIN iRCCE_mail_garbage;
 #ifdef _OPENMP
 #pragma omp threadprivate (iRCCE_isend_queue, iRCCE_irecv_queue)
 #endif