diff --git a/arch/x86/include/asm/iRCCE.h b/arch/x86/include/asm/iRCCE.h
index 60250eab..ed762ba2 100644
--- a/arch/x86/include/asm/iRCCE.h
+++ b/arch/x86/include/asm/iRCCE.h
@@ -45,6 +45,7 @@
 #define iRCCE_MAILBOX_ALL 	 	-4
 #define iRCCE_MAILBOX_OPEN		 0
 #define iRCCE_MAILBOX_CLOSED		 1
+#define iRCCE_MAILBOX_INVALID		-1
 
 // iRCCE-mailbox-system tags
 #define iRCCE_LAST_MAIL			-1
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 413c2932..7132026b 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -233,11 +233,9 @@ void irq_handler(struct state *s)
 {
 	/* This is a blank function pointer */
 	void (*handler) (struct state * s);
-
+	
 	// at first, we check our work queues
-//	if( s->int_no == 124 ) {
-		check_workqueues();
-//	}
+	check_workqueues();
 
 	/* 
 	 * Find out if we have a custom handler to run for this
diff --git a/arch/x86/scc/iRCCE_mailbox.c b/arch/x86/scc/iRCCE_mailbox.c
index 045a731d..b01907d0 100644
--- a/arch/x86/scc/iRCCE_mailbox.c
+++ b/arch/x86/scc/iRCCE_mailbox.c
@@ -24,10 +24,6 @@
 //    limitations under the License.
 // 
 //
-#include "iRCCE_lib.h"
-#include <stdlib.h>
-#include <string.h>
-#include <time.h>
 
 /**
  * 
@@ -60,7 +56,7 @@ static int iRCCE_mailbox_close_one(int rank, int check);
 
 void iRCCE_mailbox_print_header(iRCCE_MAIL_HEADER* header) {
 
-                printf( "\n"
+                kprintf( "\n"
 			"-------------------------\n"
 			"| RCK%d\n"
 			"-------------------------\n"
@@ -185,6 +181,7 @@ static int iRCCE_mailbox_check() {
 		}
 	}
 
+
 	return iRCCE_SUCCESS;
 }
 
@@ -210,7 +207,7 @@ int iRCCE_mail_recv(
 
 	int i;
 	iRCCE_MAIL_HEADER* help_header;
-	
+
 	// if there is no mail, check for incoming
 	if ( !iRCCE_mailbox_recv_queue[0].first ) {
 		iRCCE_mailbox_check();
@@ -237,6 +234,7 @@ int iRCCE_mail_recv(
 
 	// no mail queued
 	*header = NULL;
+
 	return iRCCE_MAILBOX_EMPTY;
 
 }
@@ -312,6 +310,11 @@ int iRCCE_mail_send(
 			int dest	// UE that will receive the header
 			) {
 
+	// check for an attempt to send in own mailbox
+	if( dest == RCCE_IAM ) {
+		return iRCCE_MAILBOX_INVALID;
+	}
+
 	// if dest mailbox is full, check for incoming mail
 	RC_cache_invalidate();
 	while( iRCCE_mailbox_send[dest]->sent ) {
diff --git a/arch/x86/scc/icc.c b/arch/x86/scc/icc.c
index d3cd427d..f0c8b957 100644
--- a/arch/x86/scc/icc.c
+++ b/arch/x86/scc/icc.c
@@ -192,25 +192,40 @@ int icc_halt(void)
 	uint32_t flags;
 	uint32_t do_send = 1;
 
-	do {
-		// iRCCE is not thread save => disable interrupts
-		flags = irq_nested_disable();
+	// iRCCE is not thread save => disable interrupts
+	flags = irq_nested_disable();
 
-		if (do_send) {
-			do_send = (iRCCE_isend_push() == iRCCE_PENDING);
-			iRCCE_irecv_push();
-		}
-		icc_mail_check();
+	icc_mail_check();
 
-		irq_nested_enable(flags);
-	} while(do_send);
+	irq_nested_enable(flags);
 
 	HALT;
 
 	return 0;
 }
 
-#define ROUNDS 100000
+#define ROUNDS 10000
+
+static inline void icc_mail_check_tag(iRCCE_MAIL_HEADER* mail) {
+	char* recv_buffer;
+
+	switch( mail->tag ) {
+	case iRCCE_ANYLENGTH:
+		recv_buffer = (char*)kmalloc( mail->size );
+		iRCCE_irecv(recv_buffer, mail->size, 
+				mail->source, NULL );
+		break;
+
+	case PING_REQ:
+		iRCCE_mail_send(0, PING_RESP, 0, NULL, mail->source);
+		break;
+
+	default: 
+		break;
+	}
+
+}
+
 
 int icc_mail_ping( void )
 {	
@@ -271,11 +286,9 @@ int icc_mail_ping( void )
 	return 0;
 }
 
+
 #define CORE_A 0	 	// sender
-#define CORE_B RCCE_num_ues()-1	// receiver
-#define NOISE_ROUNDS 1000000
-
-
+#define CORE_B 1		// receiver 
 int icc_mail_ping_irq( void )
 {
 	/* return if not core 0 */
@@ -285,34 +298,36 @@ int icc_mail_ping_irq( void )
 	uint64_t timer = 0;
 	int rem_rank = CORE_B;
 	int i;
+	int res;
 	iRCCE_MAIL_HEADER* recv_header = NULL;
 
 	kprintf( "Hello from mail_ping_irq ... \n" );
+	kprintf( "my_rank = %d\n", my_ue );
 	kprintf( "rem_rank = %d\n", rem_rank );	
 	// disable interrupts
 	flags = irq_nested_disable();
 	
 	for( i=0; i<ROUNDS+1; ++i ) {
-		if( my_ue == 0 ) {
-			/* send ping request */ 
-			iRCCE_mail_send(0, PING_REQ, 0, NULL, rem_rank);
-		
+		/* send ping request */ 
+		iRCCE_mail_send(0, PING_REQ, 0, NULL, rem_rank);
 
-			/* send interrupt */
-			NOP8;
-			icc_send_irq(rem_rank);
-			
-			/* wait for response */
-			do {
-				iRCCE_mail_recv(&recv_header);
-				if( recv_header->tag == PING_RESP )
+		/* send interrupt */
+		icc_send_irq(rem_rank);
+
+		/* wait for response */
+		do {
+			res = iRCCE_mail_recv(&recv_header);
+			if( res == iRCCE_SUCCESS ) {
+				if( (recv_header->source == rem_rank) 
+					&& (recv_header->tag == PING_RESP) ) 
 					break;
-			} while( 1 );
+				iRCCE_mail_release(&recv_header);
+			}
+		} while( 1 );
+		
+		/* release mail */
+		iRCCE_mail_release(&recv_header);
 
-			/* release mail */
-			iRCCE_mail_release(&recv_header);
-		}
-	
 		/* start timer in first round */
 		if( i == 0 ) timer = rdtsc();
 
@@ -321,40 +336,52 @@ int icc_mail_ping_irq( void )
 	/* stop timer */
 	timer = rdtsc() - timer;
 
+	kprintf( "timer = %ld\n", timer );
+	kprintf( "mail_pingpong needs in average %d µsec (%d ticks)!\n",
+		timer/(2*ROUNDS*533), timer/(2*ROUNDS) );
 
-	kprintf( "timer = %d\n", timer );
-	if( my_ue == 0 ) {
-		kprintf( "mail_pingpong needs in average %f µsec (%d ticks)!\n",
-				timer/(2.0*ROUNDS*533), timer/(2*ROUNDS) );
+	
+	/* recv noise mails */
+	while(1) {
+		iRCCE_mail_recv(&recv_header);
+		if(recv_header) iRCCE_mail_release(&recv_header);
 	}
 
 	irq_nested_enable(flags);
-
 	return 0;
 }
 
 
 int icc_mail_noise() {
-	int i, j;
+	int j, res;
 	int num_ranks = RCCE_num_ues();
 	iRCCE_MAIL_HEADER* recv_mail = NULL;
-	
+
+	kprintf( "Hello from icc_mail_noise: my_ue = %d\n", my_ue );
+
 	// leave function if not participating
-	if( (my_ue == CORE_A) || (my_ue == CORE_B) ) {
+	if( (my_ue == CORE_A) /*|| (my_ue == CORE_B)*/) {
 		return -1;
-	}
+	}  
 	
-	for( i=0; i<NOISE_ROUNDS; ++i ) {
+	for( ;; ) {
+		/* send a mail to each UE */
 		for( j=0; j<num_ranks; ++j ) {
-			if ( (j == CORE_A) || (j == CORE_B) ) continue;
-			iRCCE_mail_send(0, my_ue*NOISE_ROUNDS+j, 0, NULL, j);
-			iRCCE_mail_recv(&recv_mail);
-			if( recv_mail ) iRCCE_mail_release(&recv_mail);
+			iRCCE_mail_send(0, 100, 1, NULL, j);
+			res = iRCCE_mail_recv(&recv_mail);
+			if( res == iRCCE_SUCCESS ) {
+				icc_mail_check_tag(recv_mail);
+				iRCCE_mail_release(&recv_mail);
+			}
+		}
+
+		/* read some mails */
+		for( res = iRCCE_mail_recv(&recv_mail), j=0; (res == iRCCE_SUCCESS) && (j<48); res = iRCCE_mail_recv(&recv_mail), ++j ) {
+			icc_mail_check_tag(recv_mail);
+			iRCCE_mail_release(&recv_mail);	
 		}
 	}
 
-	iRCCE_mailbox_close(iRCCE_MAILBOX_ALL);
-	
 	return 0;
 }
 
@@ -362,28 +389,8 @@ void icc_mail_check(void)
 {
 	iRCCE_MAIL_HEADER* header = NULL;
 	int res;
-	char* recv_buffer;
-
-	// empty mailbox and interpret headers
-	while( 	(res = iRCCE_mail_recv( &header )) == iRCCE_SUCCESS ) {
-		switch( header->tag ) {
-		case iRCCE_ANYLENGTH:
-			recv_buffer = (char*)kmalloc( header->size );
-			iRCCE_irecv(recv_buffer, header->size, 
-					header->source, NULL );
-			iRCCE_mail_send(0, 2, 0, NULL, header->source);	
-			break;
-
-		case iRCCE_ANYLENGTH_PIGGYBACK:
-			iRCCE_mail_send(0, 2, 0, NULL, header->source);
-			break;	
-
-		case PING_REQ:
-			iRCCE_mail_send(0, PING_RESP, 0, NULL, header->source);
-			break;
-		}
-
-
+	while( (res = iRCCE_mail_recv(&header)) == iRCCE_SUCCESS ) {
+		icc_mail_check_tag(header);
 		iRCCE_mail_release( &header );
 	}
 }
diff --git a/kernel/tests.c b/kernel/tests.c
index fc4f4d39..67b3904d 100644
--- a/kernel/tests.c
+++ b/kernel/tests.c
@@ -90,11 +90,16 @@ static int STDCALL foo(void* arg)
 int STDCALL mail_ping(void* arg) {
 		//icc_mail_ping();        
 		icc_mail_ping_irq();        
-		//icc_mail_noise(); // generate noise in the mesh
 		icc_halt();
 
 	return 0;
 }
+
+int STDCALL mail_noise(void*arg) {
+	icc_mail_noise(); // generate noise in the mesh
+
+	return 0;
+}
 #endif
 
 static int STDCALL join_test(void* arg)
@@ -133,6 +138,7 @@ int test_init(void)
 	//create_kernel_task(NULL, producer, NULL);
 	//create_kernel_task(NULL, consumer, NULL);
 	create_kernel_task(NULL, mail_ping, NULL);
+	create_kernel_task(NULL, mail_noise, NULL);
 	//create_user_task(NULL, "/bin/hello", argv);
 	//create_user_task(NULL, "/bin/tests", argv);
 	//create_user_task(NULL, "/bin/jacobi", argv);