diff --git a/core/net/rpl/rpl-dag.c b/core/net/rpl/rpl-dag.c
index f1b13d684..09b900a54 100644
--- a/core/net/rpl/rpl-dag.c
+++ b/core/net/rpl/rpl-dag.c
@@ -191,8 +191,8 @@ rpl_set_root(uip_ipaddr_t *dag_id)
   dag->max_rankinc = DEFAULT_MAX_RANKINC;
   dag->min_hoprankinc = DEFAULT_MIN_HOPRANKINC;
 
-  dag->default_lifetime = DEFAULT_RPL_DEF_LIFETIME;
-  dag->lifetime_unit = DEFAULT_RPL_LIFETIME_UNIT;
+  dag->default_lifetime = RPL_DEFAULT_LIFETIME;
+  dag->lifetime_unit = RPL_DEFAULT_LIFETIME_UNIT;
 
   dag->rank = ROOT_RANK(dag);
 
@@ -238,11 +238,9 @@ rpl_set_default_route(rpl_dag_t *dag, uip_ipaddr_t *from)
     PRINTF("RPL: Adding default route through ");
     PRINT6ADDR(from);
     PRINTF("\n");
-    if(DEFAULT_ROUTE_LIFETIME == INFINITE_LIFETIME) {
-      dag->def_route = uip_ds6_defrt_add(from, 0);
-    } else {
-      dag->def_route = uip_ds6_defrt_add(from, DEFAULT_ROUTE_LIFETIME);
-    }
+    dag->def_route = uip_ds6_defrt_add(from,
+                                       RPL_LIFETIME(dag,
+                                                    dag->default_lifetime));
     if(dag->def_route == NULL) {
       return 0;
     }
diff --git a/core/net/rpl/rpl-icmp6.c b/core/net/rpl/rpl-icmp6.c
index bd39a5405..d63b5c3c1 100644
--- a/core/net/rpl/rpl-icmp6.c
+++ b/core/net/rpl/rpl-icmp6.c
@@ -467,7 +467,7 @@ dao_input(void)
   unsigned char *buffer;
   uint16_t sequence;
   uint8_t instance_id;
-  uint32_t lifetime;
+  rpl_lifetime_t lifetime;
   uint8_t prefixlen;
   uint8_t flags;
   uint8_t subopt_type;
@@ -482,7 +482,6 @@ dao_input(void)
   int learned_from;
   rpl_parent_t *p;
 
-  lifetime = 0;
   prefixlen = 0;
 
   uip_ipaddr_copy(&dao_sender_addr, &UIP_IP_BUF->srcipaddr);
@@ -495,7 +494,7 @@ dao_input(void)
   buffer = UIP_ICMP_PAYLOAD;
   buffer_length = uip_len - uip_l2_l3_icmp_hdr_len;
 #if RPL_CONF_ADJUST_LLH_LEN
-  buffer_length+=UIP_LLH_LEN; //Add jackdaw, minimal-net ethernet header
+  buffer_length += UIP_LLH_LEN; /* Add jackdaw, minimal-net ethernet header */
 #endif
 
   pos = 0;
@@ -508,6 +507,8 @@ dao_input(void)
     return;
   }
 
+  lifetime = dag->default_lifetime;
+
   flags = buffer[pos++];
   /* reserved */
   pos++;
@@ -515,19 +516,19 @@ dao_input(void)
 
   /* Is the DAGID present? */
   if(flags & RPL_DAO_D_FLAG) {
-    /* currently the DAG ID is ignored since we only use global
-       RPL Instance IDs... */
+    /* Currently the DAG ID is ignored since we only use global
+       RPL Instance IDs. */
     pos += 16;
   }
 
-  /* Check if there are any DIO suboptions. */
+  /* Check if there are any DIO sub-options. */
   i = pos;
   for(; i < buffer_length; i += len) {
     subopt_type = buffer[i];
     if(subopt_type == RPL_DIO_SUBOPT_PAD1) {
       len = 1;
     } else {
-      /* Suboption with a two-byte header + payload */
+      /* Sub-option with a two-byte header and payload */
       len = 2 + buffer[i + 1];
     }
 
@@ -539,23 +540,24 @@ dao_input(void)
       memcpy(&prefix, buffer + i + 4, (prefixlen + 7) / CHAR_BIT);
       break;
     case RPL_DIO_SUBOPT_TRANSIT:
-      /* path sequence and control ignored */
+      /* The path sequence and control are ignored. */
       pathcontrol = buffer[i + 3];
       pathsequence = buffer[i + 4];
       lifetime = buffer[i + 5];
-      /* parent address also ignored */
+      /* The parent address is also ignored. */
       break;
     }
   }
 
-  PRINTF("RPL: DAO lifetime: %lu, prefix length: %u prefix: ",
-         (unsigned long)lifetime, (unsigned)prefixlen);
+  PRINTF("RPL: DAO lifetime: %u, prefix length: %u prefix: ",
+         (unsigned)lifetime, (unsigned)prefixlen);
   PRINT6ADDR(&prefix);
   PRINTF("\n");
 
+  rep = uip_ds6_route_lookup(&prefix);
+
   if(lifetime == ZERO_LIFETIME) {
     /* No-Path DAO received; invoke the route purging routine. */
-    rep = uip_ds6_route_lookup(&prefix);
     if(rep != NULL && rep->state.saved_lifetime == 0) {
       PRINTF("RPL: Setting expiration timer for prefix ");
       PRINT6ADDR(&prefix);
@@ -570,12 +572,9 @@ dao_input(void)
                  RPL_ROUTE_FROM_MULTICAST_DAO : RPL_ROUTE_FROM_UNICAST_DAO;
 
   if(learned_from == RPL_ROUTE_FROM_UNICAST_DAO) {
-    /* Check if this is a DAO forwarding loop. */
+    /* Check whether this is a DAO forwarding loop. */
     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)) {
       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));
       p->rank = INFINITE_RANK;
@@ -584,16 +583,18 @@ dao_input(void)
     }
   }
 
-  rep = rpl_add_route(dag, &prefix, prefixlen, &dao_sender_addr);
   if(rep == NULL) {
-    RPL_STAT(rpl_stats.mem_overflows++);
-    PRINTF("RPL: Could not add a route after receiving a DAO\n");
-    return;
-  } else {
-    rep->state.lifetime = lifetime * dag->lifetime_unit;
-    rep->state.learned_from = learned_from;
+    rep = rpl_add_route(dag, &prefix, prefixlen, &dao_sender_addr);
+    if(rep == NULL) {
+      RPL_STAT(rpl_stats.mem_overflows++);
+      PRINTF("RPL: Could not add a route after receiving a DAO\n");
+      return;
+    }
   }
 
+  rep->state.lifetime = RPL_LIFETIME(dag, lifetime);
+  rep->state.learned_from = learned_from;
+
   if(learned_from == RPL_ROUTE_FROM_UNICAST_DAO) {
     if(dag->preferred_parent) {
       PRINTF("RPL: Forwarding DAO to parent ");
@@ -608,7 +609,7 @@ dao_input(void)
 }
 /*---------------------------------------------------------------------------*/
 void
-dao_output(rpl_parent_t *n, uint32_t lifetime)
+dao_output(rpl_parent_t *n, rpl_lifetime_t lifetime)
 {
   rpl_dag_t *dag;
   unsigned char *buffer;
@@ -656,13 +657,13 @@ dao_output(rpl_parent_t *n, uint32_t lifetime)
   memcpy(buffer + pos, &prefix, (prefixlen + 7) / CHAR_BIT);
   pos += ((prefixlen + 7) / CHAR_BIT);
 
-  /* create a transit information subopt (RPL-18)*/
+  /* Create a transit information sub-option. */
   buffer[pos++] = RPL_DIO_SUBOPT_TRANSIT;
   buffer[pos++] = 4;
   buffer[pos++] = 0; /* flags - ignored */
   buffer[pos++] = 0; /* path control - ignored */
   buffer[pos++] = 0; /* path seq - ignored */
-  buffer[pos++] = (lifetime / dag->lifetime_unit) & 0xff;
+  buffer[pos++] = lifetime;
 
   if(n == NULL) {
     uip_create_linklocal_rplnodes_mcast(&addr);
diff --git a/core/net/rpl/rpl-private.h b/core/net/rpl/rpl-private.h
index 4363c55ad..db3ef8515 100644
--- a/core/net/rpl/rpl-private.h
+++ b/core/net/rpl/rpl-private.h
@@ -101,14 +101,14 @@
 /* Special value indicating immediate removal. */
 #define ZERO_LIFETIME                   0
 
-/* Special value indicating that a DAO should not expire. */
-#define INFINITE_LIFETIME               0xffffffff
+/* Default route lifetime unit. */
+#define RPL_DEFAULT_LIFETIME_UNIT       0xffff
 
-/* Default route lifetime in seconds. */
-#define DEFAULT_ROUTE_LIFETIME          INFINITE_LIFETIME
+/* Default route lifetime as a multiple of the lifetime unit. */
+#define RPL_DEFAULT_LIFETIME        0xff
 
-#define DEFAULT_RPL_LIFETIME_UNIT       0xffff
-#define DEFAULT_RPL_DEF_LIFETIME        0xff
+#define RPL_LIFETIME(dag, lifetime) \
+          ((unsigned long)(dag)->lifetime_unit * lifetime)
 
 #ifndef RPL_CONF_MIN_HOPRANKINC
 #define DEFAULT_MIN_HOPRANKINC          256
@@ -207,7 +207,7 @@ struct rpl_dio {
   uint8_t dag_intdoubl;
   uint8_t dag_intmin;
   uint8_t dag_redund;
-  uint8_t default_lifetime;
+  rpl_lifetime_t default_lifetime;
   uint16_t lifetime_unit;
   rpl_rank_t dag_max_rankinc;
   rpl_rank_t dag_min_hoprankinc;
@@ -243,7 +243,7 @@ extern rpl_stats_t rpl_stats;
 /* ICMPv6 functions for RPL. */
 void dis_output(uip_ipaddr_t *addr);
 void dio_output(rpl_dag_t *, uip_ipaddr_t *uc_addr);
-void dao_output(rpl_parent_t *, uint32_t lifetime);
+void dao_output(rpl_parent_t *, rpl_lifetime_t lifetime);
 void dao_ack_output(rpl_dag_t *, uip_ipaddr_t *, uint8_t);
 void uip_rpl_input(void);
 
diff --git a/core/net/rpl/rpl-timers.c b/core/net/rpl/rpl-timers.c
index aa5e6d086..dbb7d2392 100644
--- a/core/net/rpl/rpl-timers.c
+++ b/core/net/rpl/rpl-timers.c
@@ -201,14 +201,13 @@ handle_dao_timer(void *ptr)
     return;
   }
 
-  /* Send the DAO to the best parent. rpl-07 section C.2 lists the
-     fan-out as being under investigation. */
+  /* Send the DAO to the DAO parent set -- the preferred parent in our case. */
   if(dag->preferred_parent != NULL) {
     PRINTF("RPL: handle_dao_timer - sending DAO\n");
-    /* set time to maxtime */
-    dao_output(dag->preferred_parent, dag->lifetime_unit * 0xffUL);
+    /* Set the route lifetime to the default value. */
+    dao_output(dag->preferred_parent, dag->default_lifetime);
   } else {
-    PRINTF("RPL: Could not find a parent to send a DAO to \n");
+    PRINTF("RPL: No suitable DAO parent\n");
   }
   ctimer_stop(&dag->dao_timer);
 }
diff --git a/core/net/rpl/rpl.c b/core/net/rpl/rpl.c
index b41fbeea7..7c5e05d21 100644
--- a/core/net/rpl/rpl.c
+++ b/core/net/rpl/rpl.c
@@ -107,7 +107,7 @@ rpl_add_route(rpl_dag_t *dag, uip_ipaddr_t *prefix, int prefix_len,
     uip_ipaddr_copy(&rep->nexthop, next_hop);
   }
   rep->state.dag = dag;
-  rep->state.lifetime = DEFAULT_ROUTE_LIFETIME;
+  rep->state.lifetime = RPL_LIFETIME(dag, dag->default_lifetime);
   rep->state.learned_from = RPL_ROUTE_FROM_INTERNAL;
 
   PRINTF("RPL: Added a route to ");
diff --git a/core/net/rpl/rpl.h b/core/net/rpl/rpl.h
index c55ee6cd0..af16326d9 100644
--- a/core/net/rpl/rpl.h
+++ b/core/net/rpl/rpl.h
@@ -83,6 +83,7 @@
 #define RPL_PARENT_COUNT(dag)   list_length((dag)->parents)
 /*---------------------------------------------------------------------------*/
 typedef uint16_t rpl_rank_t;
+typedef uint8_t rpl_lifetime_t;
 typedef uint16_t rpl_ocp_t;
 
 /*---------------------------------------------------------------------------*/