diff --git a/core/net/rpl/rpl-dag.c b/core/net/rpl/rpl-dag.c
index d50b57d90..f1bf064eb 100644
--- a/core/net/rpl/rpl-dag.c
+++ b/core/net/rpl/rpl-dag.c
@@ -32,7 +32,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: rpl-dag.c,v 1.39 2010/12/10 22:48:31 joxe Exp $
+ * $Id: rpl-dag.c,v 1.40 2010/12/13 10:54:25 nvt-se Exp $
  */
 /**
  * \file
@@ -117,9 +117,8 @@ remove_parents(rpl_dag_t *dag, rpl_rank_t minimum_rank)
 static int
 should_send_dao(rpl_dag_t *dag, rpl_dio_t *dio, rpl_parent_t *p)
 {
-  return dio->dst_adv_supported;
-/*  return dio->dst_adv_supported && dio->dst_adv_trigger &&
-         dio->dtsn > p->dtsn && p == dag->preferred_parent;*/
+  return 1;
+/*  return dio->dtsn > p->dtsn && p == dag->preferred_parent;*/
 }
 /************************************************************************/
 static int
@@ -153,6 +152,7 @@ rpl_set_root(uip_ipaddr_t *dag_id)
   dag->joined = 1;
   dag->version = version + 1;
   dag->grounded = RPL_GROUNDED;
+  dag->mop = RPL_MOP_DEFAULT;
   dag->rank = ROOT_RANK;
   dag->of = rpl_find_of(RPL_DEFAULT_OCP);
   dag->preferred_parent = NULL;
@@ -444,8 +444,9 @@ join_dag(uip_ipaddr_t *from, rpl_dio_t *dio)
   dag->joined = 1;
   dag->used = 1;
   dag->of = of;
-  dag->preference = dio->preference;
   dag->grounded = dio->grounded;
+  dag->mop = dio->mop;
+  dag->preference = dio->preference;
   dag->instance_id = dio->instance_id;
 
   dag->max_rankinc = dio->dag_max_rankinc;
@@ -477,7 +478,7 @@ join_dag(uip_ipaddr_t *from, rpl_dio_t *dio)
   if(should_send_dao(dag, dio, p)) {
     rpl_schedule_dao(dag);
   } else {
-    PRINTF("RPL: dst_adv_trigger not set in incoming DIO!\n");
+    PRINTF("RPL: The DIO does not meet the prerequisites for sending a DAO\n");
   }
 }
 /************************************************************************/
@@ -605,6 +606,11 @@ rpl_process_dio(uip_ipaddr_t *from, rpl_dio_t *dio)
   rpl_dag_t *dag;
   rpl_parent_t *p;
 
+  if(dio->mop != RPL_MOP_DEFAULT) {
+    PRINTF("RPL: Ignoring a DIO with an unsupported MOP: %d\n", dio->mop);
+    return;
+  }
+
   dag = rpl_get_dag(dio->instance_id);
   if(dag == NULL) {
     /* Join the first possible DAG of this RPL instance. */
diff --git a/core/net/rpl/rpl-icmp6.c b/core/net/rpl/rpl-icmp6.c
index 1ae4e2d71..d853790ad 100644
--- a/core/net/rpl/rpl-icmp6.c
+++ b/core/net/rpl/rpl-icmp6.c
@@ -32,7 +32,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: rpl-icmp6.c,v 1.30 2010/12/13 09:59:46 joxe Exp $
+ * $Id: rpl-icmp6.c,v 1.31 2010/12/13 10:54:25 nvt-se Exp $
  */
 /**
  * \file
@@ -59,14 +59,10 @@
 #include "net/uip-debug.h"
 
 /*---------------------------------------------------------------------------*/
-#define RPL_DIO_GROUNDED            0x80
-#define RPL_DIO_DEST_ADV_SUPPORTED  0x40
-#define RPL_DIO_DEST_ADV_TRIGGER    0x20
-#define RPL_DIO_MOP_MASK            0x18
-#define RPL_DIO_MOP_NON_STORING     0x00
-#define RPL_DIO_MOP_STORING         0x10
-#define RPL_DIO_DAG_PREFERENCE_MASK 0x07
-
+#define RPL_DIO_GROUNDED                 0x80
+#define RPL_DIO_MOP_SHIFT                3
+#define RPL_DIO_MOP_MASK                 0x3c
+#define RPL_DIO_PREFERENCE_MASK          0x07
 
 #define UIP_IP_BUF       ((struct uip_ip_hdr *)&uip_buf[UIP_LLH_LEN])
 #define UIP_ICMP_BUF     ((struct uip_icmp_hdr *)&uip_buf[uip_l2_l3_hdr_len])
@@ -142,11 +138,11 @@ dis_output(uip_ipaddr_t *addr)
   unsigned char *buffer;
   uip_ipaddr_t tmpaddr;
 
-  /* DAG Information Solicitation  - 2 bytes flags and reserved */
+  /* DAG Information Solicitation  - 2 bytes reserved */
   /*      0                   1                   2        */
   /*      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3  */
   /*     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */
-  /*     |    flags      | reserved      |   Option(s)...  */
+  /*     |     Flags     |   Reserved    |   Option(s)...  */
   /*     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */
 
   buffer = UIP_ICMP_PAYLOAD;
@@ -160,7 +156,6 @@ dis_output(uip_ipaddr_t *addr)
     PRINTF("RPL: Sending a unicast DIS\n");
   }
   uip_icmp6_send(addr, ICMP6_RPL, RPL_CODE_DIS, 2);
-
 }
 /*---------------------------------------------------------------------------*/
 static void
@@ -216,9 +211,8 @@ dio_input(void)
   PRINTF("RPL: Incoming DIO rank %u\n", (unsigned)dio.rank);
 
   dio.grounded = buffer[i] & RPL_DIO_GROUNDED;
-  dio.dst_adv_trigger = buffer[i] & RPL_DIO_DEST_ADV_TRIGGER;
-  dio.dst_adv_supported = buffer[i] & RPL_DIO_DEST_ADV_SUPPORTED;
-  dio.preference = buffer[i++] & RPL_DIO_DAG_PREFERENCE_MASK;
+  dio.mop = (buffer[i]& RPL_DIO_MOP_MASK) >> RPL_DIO_MOP_SHIFT;
+  dio.preference = buffer[i++] & RPL_DIO_PREFERENCE_MASK;
 
   dio.dtsn = buffer[i++];
   /* two reserved bytes */
@@ -314,7 +308,7 @@ dio_output(rpl_dag_t *dag, uip_ipaddr_t *uc_addr)
   int pos;
   uip_ipaddr_t addr;
 
-  /* DIO - DODAG Information Object */
+  /* DAG Information Solicitation */
   pos = 0;
 
   buffer = UIP_ICMP_PAYLOAD;
@@ -327,8 +321,8 @@ dio_output(rpl_dag_t *dag, uip_ipaddr_t *uc_addr)
   if(dag->grounded) {
     buffer[pos] |= RPL_DIO_GROUNDED;
   }
-  /* Set dst_adv_trigger and dst_adv_supported. */
-  buffer[pos] |= RPL_DIO_DEST_ADV_SUPPORTED | RPL_DIO_DEST_ADV_TRIGGER;
+
+  buffer[pos] = dag->mop << RPL_DIO_MOP_SHIFT;
   pos++;
 
   buffer[pos++] = ++dag->dtsn_out;
@@ -441,7 +435,7 @@ dao_input(void)
   pos++;
   sequence = buffer[pos++];
 
-  /* is the DAGID present ? */
+  /* Is the DAGID present? */
   if(flags & RPL_DAO_D_FLAG) {
     /* currently the DAG ID is ignored since we only use global
        RPL Instance IDs... */
@@ -500,10 +494,10 @@ dao_input(void)
     p = rpl_find_parent(dag, &dao_sender_addr);
     /* check if this is a new DAO registration with an "illegal" rank */
     /* if we already route to this node it is likely */
-    if(p != NULL && DAG_RANK(p->rank, dag) < DAG_RANK(dag->rank, dag)) {// &&
-      //       uip_ds6_route_lookup(&prefix) == NULL) {
+    if(p != NULL && DAG_RANK(p->rank, dag) < DAG_RANK(dag->rank, dag) 
+      /* && uip_ds6_route_lookup(&prefix) == NULL*/) {
       PRINTF("RPL: Loop detected when receiving a unicast DAO from a node with a lower rank! (%u < %u)\n",
-             DAG_RANK(p->rank, dag), DAG_RANK(dag->rank, dag));
+          DAG_RANK(p->rank, dag), DAG_RANK(dag->rank, dag));
       rpl_local_repair(dag);
       return;
     }
diff --git a/core/net/rpl/rpl.h b/core/net/rpl/rpl.h
index c6adaf32e..d298c4268 100644
--- a/core/net/rpl/rpl.h
+++ b/core/net/rpl/rpl.h
@@ -30,7 +30,7 @@
  *
  * Author: Joakim Eriksson, Nicolas Tsiftes
  *
- * $Id: rpl.h,v 1.23 2010/10/28 20:39:06 joxe Exp $
+ * $Id: rpl.h,v 1.24 2010/12/13 10:54:25 nvt-se Exp $
  */
 
 #ifndef RPL_H
@@ -137,6 +137,13 @@
 #define RPL_ROUTE_FROM_MULTICAST_DAO    2
 #define RPL_ROUTE_FROM_DIO              3
 
+/* DAG Mode of Operation */
+#define RPL_MOP_NO_DOWNWARD_ROUTES      0
+#define RPL_MOP_NON_STORING             1
+#define RPL_MOP_STORING_NO_MULTICAST    2
+#define RPL_MOP_STORING_MULTICAST       3
+#define RPL_MOP_DEFAULT                 RPL_MOP_STORING_NO_MULTICAST
+
 /* DAG Metric Container Object Types, to be confirmed by IANA. */
 #define RPL_DAG_MC_NSA                  1
 #define RPL_DAG_MC_NE                   2
@@ -224,8 +231,7 @@ struct rpl_dio {
   rpl_ocp_t ocp;
   rpl_rank_t rank;
   uint8_t grounded;
-  uint8_t dst_adv_trigger;
-  uint8_t dst_adv_supported;
+  uint8_t mop;
   uint8_t preference;
   uint8_t version;
   uint8_t instance_id;
@@ -271,8 +277,9 @@ struct rpl_dag {
   uint8_t dtsn_out;
   uint8_t instance_id;
   uint8_t version;
-  uint8_t preference;
   uint8_t grounded;
+  uint8_t mop;
+  uint8_t preference;
   uint8_t dio_intdoubl;
   uint8_t dio_intmin;
   uint8_t dio_redundancy;