diff --git a/core/net/rime/nbh.h b/core/net/rime/nbh.h
index ad6c06d5f..a43263d38 100644
--- a/core/net/rime/nbh.h
+++ b/core/net/rime/nbh.h
@@ -28,7 +28,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: nbh.h,v 1.1 2007/11/13 21:01:54 adamdunkels Exp $
+ * $Id: nbh.h,v 1.2 2007/11/17 10:32:54 adamdunkels Exp $
  */
 
 /**
@@ -46,7 +46,7 @@
 struct nbh_conn;
 
 struct nbh_callbacks {
-  int (* recv)(struct nbh_conn *c, rimeaddr_t *from, uint16_t val);
+  void (* recv)(struct nbh_conn *c, rimeaddr_t *from, uint16_t val);
   void (* sent)(struct nbh_conn *c);
 };
 
diff --git a/core/net/rime/neighbor.c b/core/net/rime/neighbor.c
index 4281843a7..846930033 100644
--- a/core/net/rime/neighbor.c
+++ b/core/net/rime/neighbor.c
@@ -33,7 +33,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: neighbor.c,v 1.10 2007/11/13 20:39:29 adamdunkels Exp $
+ * $Id: neighbor.c,v 1.11 2007/11/17 10:32:54 adamdunkels Exp $
  */
 
 /**
@@ -108,12 +108,11 @@ neighbor_find(rimeaddr_t *addr)
 }
 /*---------------------------------------------------------------------------*/
 void
-neighbor_update(struct neighbor *n, u8_t rtmetric, u8_t etx)
+neighbor_update(struct neighbor *n, u8_t rtmetric)
 {
   if(n != NULL) {
     n->rtmetric = rtmetric;
     n->time = 0;
-    neighbor_update_etx(n, etx);
   }
 }
 /*---------------------------------------------------------------------------*/
diff --git a/core/net/rime/neighbor.h b/core/net/rime/neighbor.h
index bbf6c2ea5..602012392 100644
--- a/core/net/rime/neighbor.h
+++ b/core/net/rime/neighbor.h
@@ -38,7 +38,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: neighbor.h,v 1.6 2007/11/13 20:39:29 adamdunkels Exp $
+ * $Id: neighbor.h,v 1.7 2007/11/17 10:32:54 adamdunkels Exp $
  */
 
 /**
@@ -68,7 +68,7 @@ void neighbor_init(void);
 /*void neighbor_periodic(int max_time);*/
 
 void neighbor_add(rimeaddr_t *addr, u8_t rtmetric, u8_t etx);
-void neighbor_update(struct neighbor *n, u8_t rtmetric, u8_t etx);
+void neighbor_update(struct neighbor *n, u8_t rtmetric);
 void neighbor_update_etx(struct neighbor *n, u8_t etx);
 void neighbor_timedout_etx(struct neighbor *n, u8_t etx);
 void neighbor_remove(rimeaddr_t *addr);
diff --git a/core/net/rime/tree.c b/core/net/rime/tree.c
index b053b150a..4c62464ed 100644
--- a/core/net/rime/tree.c
+++ b/core/net/rime/tree.c
@@ -33,7 +33,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: tree.c,v 1.13 2007/11/13 20:39:29 adamdunkels Exp $
+ * $Id: tree.c,v 1.14 2007/11/17 10:32:54 adamdunkels Exp $
  */
 
 /**
@@ -60,21 +60,24 @@
 #include <stdio.h>
 #include <stddef.h>
 
-/*
-struct adv_msg {
-  u8_t rtmetric;
-  u8_t pad;
-};
-*/
-
 struct hdr {
   rimeaddr_t originator;
   u8_t originator_seqno;
-  u8_t rtmetric;
+  u8_t hops;
   u8_t hoplim;
   u8_t rexmits;
 };
 
+#define NUM_RECENT_PACKETS 4
+
+struct recent_packet {
+  rimeaddr_t originator;
+  uint8_t seqno;
+};
+
+static struct recent_packet recent_packets[NUM_RECENT_PACKETS];
+static uint8_t recent_packet_ptr;
+
 #define SINK 0
 #define RTMETRIC_MAX TREE_MAX_DEPTH
 
@@ -142,73 +145,6 @@ update_rtmetric(struct tree_conn *tc)
   }
 #endif
 }
-#if 0
-/*---------------------------------------------------------------------------*/
-static void
-send_adv(struct tree_conn *tc, clock_time_t interval)
-{
-  struct adv_msg *hdr;
-
-  rimebuf_clear();
-  rimebuf_set_datalen(sizeof(struct adv_msg));
-  hdr = rimebuf_dataptr();
-  hdr->rtmetric = tc->local_rtmetric;
-  ipolite_send(&tc->ipolite_conn, interval, rimebuf_totlen());
-}
-/*---------------------------------------------------------------------------*/
-static void
-adv_packet_received(struct ipolite_conn *c, rimeaddr_t *from)
-{
-  struct tree_conn *tc = (struct tree_conn *)
-    ((char *)c - offsetof(struct tree_conn, ipolite_conn));
-  struct adv_msg *msg = rimebuf_dataptr();
-  struct neighbor *n;
-
-  /*  PRINTF("%d.%d: adv_packet_received from %d.%d with rtmetric %d\n",
-	 rimeaddr_node_addr.u8[0], rimeaddr_node_addr.u8[1],
-	 from->u8[0], from->u8[1], msg->rtmetric);*/
-
-  n = neighbor_find(from);
-
-  if(n == NULL) {
-    neighbor_add(from, msg->rtmetric, radio_sensor.value(1));
-  } else {
-    neighbor_update(n, msg->rtmetric, radio_sensor.value(1));
-    PRINTF("%d.%d: updating neighbor %d.%d, radio sensor %d, hops %d\n",
-	   rimeaddr_node_addr.u8[0], rimeaddr_node_addr.u8[1],
-	   n->addr.u8[0], n->addr.u8[1],
-	   radio_sensor.value(1), msg->rtmetric);
-  }
-
-  update_rtmetric(tc);
-
-}
-/*---------------------------------------------------------------------------*/
-static void
-adv_packet_sent(struct ipolite_conn *c)
-{
-  struct tree_conn *tc = (struct tree_conn *)
-    ((char *)c - offsetof(struct tree_conn, ipolite_conn));
-  /*  send_adv(tc, MAX_INTERVAL);*/
-}
-/*---------------------------------------------------------------------------*/
-static void
-adv_packet_dropped(struct ipolite_conn *c)
-{
-  struct tree_conn *tc = (struct tree_conn *)
-    ((char *)c - offsetof(struct tree_conn, ipolite_conn));
-  /*  send_adv(tc, MAX_INTERVAL);*/
-}
-/*---------------------------------------------------------------------------*/
-static void
-send_timer(void *ptr)
-{
-  struct tree_conn *tc = ptr;
-
-  send_adv(tc, MAX_INTERVAL / 2);
-  ctimer_set(&tc->t, MAX_INTERVAL, send_timer, tc);
-}
-#endif /* 0 */
 /*---------------------------------------------------------------------------*/
 static int
 node_packet_received(struct ruc_conn *c, rimeaddr_t *from, u8_t seqno)
@@ -217,9 +153,27 @@ node_packet_received(struct ruc_conn *c, rimeaddr_t *from, u8_t seqno)
     ((char *)c - offsetof(struct tree_conn, ruc_conn));
   struct hdr *hdr = rimebuf_dataptr();
   struct neighbor *n;
+  int i;
 
+  /* To protect against forwarding duplicate packets, we keep a list
+     of recently forwarded packet seqnos. If the seqno of the current
+     packet exists in the list, we drop the packet. */
+
+  for(i = 0; i < NUM_RECENT_PACKETS; i++) {
+    if(recent_packets[i].seqno == hdr->originator_seqno &&
+       rimeaddr_cmp(&recent_packets[i].originator, &hdr->originator)) {
+      /* Drop the packet. */
+      return 1;
+    }
+  }
+  recent_packets[recent_packet_ptr].seqno = hdr->originator_seqno;
+  rimeaddr_copy(&recent_packets[recent_packet_ptr].originator, &hdr->originator);
+  recent_packet_ptr = (recent_packet_ptr + 1) % NUM_RECENT_PACKETS;
+  
   if(tc->local_rtmetric == SINK) {
 
+    /* If we are the sink, we call the receive function. */
+    
     rimebuf_hdrreduce(sizeof(struct hdr));
     
     PRINTF("%d.%d: sink received packet from %d.%d via %d.%d with rtmetric %d\n",
@@ -229,10 +183,14 @@ node_packet_received(struct ruc_conn *c, rimeaddr_t *from, u8_t seqno)
     
     if(tc->cb->recv != NULL) {
       tc->cb->recv(&hdr->originator, hdr->originator_seqno,
-		   hdr->rtmetric);
+		   hdr->hops);
     }
     return 1;
   } else if(hdr->hoplim > 1 && tc->local_rtmetric != RTMETRIC_MAX) {
+
+    /* If we are not the sink, we forward the packet to the best
+       neighbor. */
+    hdr->hops++;
     hdr->hoplim--;
 
         
@@ -267,6 +225,7 @@ node_packet_sent(struct ruc_conn *c, rimeaddr_t *to, u8_t retransmissions)
 
   tc->forwarding = 0;
   neighbor_update_etx(neighbor_find(to), retransmissions);
+  update_rtmetric(tc);
 }
 /*---------------------------------------------------------------------------*/
 static void
@@ -277,6 +236,7 @@ node_packet_timedout(struct ruc_conn *c, rimeaddr_t *to, u8_t retransmissions)
 
   tc->forwarding = 0;
   neighbor_timedout_etx(neighbor_find(to), retransmissions);
+  update_rtmetric(tc);
 }
 /*---------------------------------------------------------------------------*/
 static void
@@ -293,7 +253,7 @@ adv_received(struct nbh_conn *c, rimeaddr_t *from, uint16_t rtmetric)
       neighbor_add(from, rtmetric, 1);
     }
   } else {
-    neighbor_update(n, rtmetric, 1);
+    neighbor_update(n, rtmetric);
     PRINTF("%d.%d: updating neighbor %d.%d, etx %d, hops %d\n",
 	   rimeaddr_node_addr.u8[0], rimeaddr_node_addr.u8[1],
 	   n->addr.u8[0], n->addr.u8[1],
@@ -303,8 +263,6 @@ adv_received(struct nbh_conn *c, rimeaddr_t *from, uint16_t rtmetric)
   update_rtmetric(tc);
 }
 /*---------------------------------------------------------------------------*/
-/*static const struct ipolite_callbacks ipolite_callbacks =
-  {adv_packet_received, adv_packet_sent, adv_packet_dropped};*/
 static const struct ruc_callbacks ruc_callbacks = {node_packet_received,
 						   node_packet_sent,
 						   node_packet_timedout};
@@ -315,19 +273,15 @@ void
 tree_open(struct tree_conn *tc, u16_t channels,
 	  const struct tree_callbacks *cb)
 {
-  /*  ipolite_open(&tc->ipolite_conn, channels, &ipolite_callbacks);*/
   nbh_open(&tc->nbh_conn, channels, &nbh_callbacks);
   ruc_open(&tc->ruc_conn, channels + 1, &ruc_callbacks);
   tc->local_rtmetric = RTMETRIC_MAX;
   tc->cb = cb;
-  /*  send_adv(tc, MAX_INTERVAL);
-      ctimer_set(&tc->t, MAX_INTERVAL, send_timer, tc);*/
 }
 /*---------------------------------------------------------------------------*/
 void
 tree_close(struct tree_conn *tc)
 {
-  /*  ipolite_close(&tc->ipolite_conn);*/
   nbh_close(&tc->nbh_conn);
   ruc_close(&tc->ruc_conn);
 }
@@ -337,7 +291,6 @@ tree_set_sink(struct tree_conn *tc, int should_be_sink)
 {
   if(should_be_sink) {
     tc->local_rtmetric = SINK;
-    /*    send_adv(tc, MIN_INTERVAL);*/
     nbh_start(&tc->nbh_conn, tc->local_rtmetric);
   } else {
     tc->local_rtmetric = RTMETRIC_MAX;
@@ -356,13 +309,13 @@ tree_send(struct tree_conn *tc, int rexmits)
     hdr = rimebuf_hdrptr();
     hdr->originator_seqno = tc->seqno++;
     rimeaddr_copy(&hdr->originator, &rimeaddr_node_addr);
-    hdr->rtmetric = tc->local_rtmetric;
+    hdr->hops = 0;
     hdr->hoplim = MAX_HOPLIM;
     hdr->rexmits = rexmits;
     if(tc->local_rtmetric == 0) {
       if(tc->cb->recv != NULL) {
 	tc->cb->recv(&hdr->originator, hdr->originator_seqno,
-		     hdr->rtmetric);
+		     hdr->hops);
       }
     } else {
       n = neighbor_best();