diff --git a/core/net/mac/phase.c b/core/net/mac/phase.c
index e97e7eb02..0cedd8cd2 100644
--- a/core/net/mac/phase.c
+++ b/core/net/mac/phase.c
@@ -28,7 +28,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: phase.c,v 1.14 2010/06/15 19:22:25 adamdunkels Exp $
+ * $Id: phase.c,v 1.15 2010/09/13 13:39:05 adamdunkels Exp $
  */
 
 /**
@@ -57,7 +57,9 @@ struct phase_queueitem {
 #define PHASE_DEFER_THRESHOLD 1
 #define PHASE_QUEUESIZE       8
 
-#define MAX_NOACKS            3
+#define MAX_NOACKS            16
+
+#define MAX_NOACKS_TIME       CLOCK_SECOND * 16
 
 MEMB(queued_packets_memb, struct phase_queueitem, PHASE_QUEUESIZE);
 
@@ -114,7 +116,10 @@ phase_update(const struct phase_list *list,
     if(mac_status == MAC_TX_NOACK) {
       PRINTF("phase noacks %d to %d.%d\n", e->noacks, neighbor->u8[0], neighbor->u8[1]);
       e->noacks++;
-      if(e->noacks >= MAX_NOACKS) {
+      if(e->noacks == 1) {
+        timer_set(&e->noacks_timer, MAX_NOACKS_TIME);
+      }
+      if(e->noacks >= MAX_NOACKS || timer_expired(&e->noacks_timer)) {
         list_remove(*list->list, e);
         memb_free(list->memb, e);
         return;
diff --git a/core/net/mac/phase.h b/core/net/mac/phase.h
index 26591cc58..ce11cebfc 100644
--- a/core/net/mac/phase.h
+++ b/core/net/mac/phase.h
@@ -28,7 +28,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: phase.h,v 1.4 2010/04/03 13:28:30 adamdunkels Exp $
+ * $Id: phase.h,v 1.5 2010/09/13 13:39:05 adamdunkels Exp $
  */
 
 /**
@@ -42,6 +42,7 @@
 #define PHASE_H
 
 #include "net/rime/rimeaddr.h"
+#include "sys/timer.h"
 #include "sys/rtimer.h"
 #include "lib/list.h"
 #include "lib/memb.h"
@@ -52,6 +53,7 @@ struct phase {
   rimeaddr_t neighbor;
   rtimer_clock_t time;
   uint8_t noacks;
+  struct timer noacks_timer;
 };
 
 struct phase_list {