diff --git a/os/net/app-layer/coap/coap.h b/os/net/app-layer/coap/coap.h
index 9d88886af..616f67d5c 100644
--- a/os/net/app-layer/coap/coap.h
+++ b/os/net/app-layer/coap/coap.h
@@ -46,7 +46,7 @@
 
 /* sanity check for configured values */
 #define COAP_MAX_PACKET_SIZE  (COAP_MAX_HEADER_SIZE + REST_MAX_CHUNK_SIZE)
-#if COAP_MAX_PACKET_SIZE > (UIP_BUFSIZE - UIP_IPH_LEN - UIP_UDPH_LEN)
+#if COAP_MAX_PACKET_SIZE > (UIP_BUFSIZE - UIP_LLH_LEN - UIP_IPH_LEN - UIP_UDPH_LEN)
 #error "UIP_CONF_BUFFER_SIZE too small for REST_MAX_CHUNK_SIZE"
 #endif
 
diff --git a/os/net/ipv6/sicslowpan.c b/os/net/ipv6/sicslowpan.c
index 4509c3e08..060699e93 100644
--- a/os/net/ipv6/sicslowpan.c
+++ b/os/net/ipv6/sicslowpan.c
@@ -123,7 +123,7 @@
 /* NOTE: In the multiple-reassembly context there is only room for the header / first fragment */
 #define SICSLOWPAN_IP_BUF(buf)   ((struct uip_ip_hdr *)buf)
 #define SICSLOWPAN_UDP_BUF(buf)  ((struct uip_udp_hdr *)&buf[UIP_IPH_LEN])
-#define SICSLOWPAN_IPPAYLOAD_BUF(buf) (&buf[UIP_LLIPH_LEN])
+#define SICSLOWPAN_IPPAYLOAD_BUF(buf) (&buf[UIP_IPH_LEN])
 
 
 #define UIP_IP_BUF          ((struct uip_ip_hdr *)&uip_buf[UIP_LLH_LEN])
diff --git a/os/net/ipv6/tcpip.c b/os/net/ipv6/tcpip.c
index d6207400b..e096ce44b 100644
--- a/os/net/ipv6/tcpip.c
+++ b/os/net/ipv6/tcpip.c
@@ -472,12 +472,7 @@ output_fallback(void)
 #ifdef UIP_FALLBACK_INTERFACE
   LOG_INFO("fallback: removing ext hdrs & setting proto %d %d\n",
          uip_ext_len, *((uint8_t *)UIP_IP_BUF + 40));
-  if(uip_ext_len > 0) {
-    uint8_t proto = *((uint8_t *)UIP_IP_BUF + 40);
-    remove_ext_hdr();
-    /* This should be copied from the ext header... */
-    UIP_IP_BUF->proto = proto;
-  }
+  remove_ext_hdr();
   /* Inform the other end that the destination is not reachable. If it's
    * not informed routes might get lost unexpectedly until there's a need
    * to send a new packet to the peer */
diff --git a/os/net/ipv6/uip6.c b/os/net/ipv6/uip6.c
index 4ae366d2f..72384414a 100644
--- a/os/net/ipv6/uip6.c
+++ b/os/net/ipv6/uip6.c
@@ -523,6 +523,7 @@ uip_connect(const uip_ipaddr_t *ripaddr, uint16_t rport)
 void
 remove_ext_hdr(void)
 {
+  int last_uip_ext_len;
   /* Remove ext header before TCP/UDP processing. */
   if(uip_ext_len > 0) {
     LOG_DBG("Cutting ext-header before processing (extlen: %d, uiplen: %d)\n",
@@ -532,15 +533,17 @@ remove_ext_hdr(void)
       uip_clear_buf();
       return;
     }
-    memmove(((uint8_t *)UIP_TCP_BUF), (uint8_t *)UIP_TCP_BUF + uip_ext_len,
-            uip_len - UIP_IPH_LEN - uip_ext_len);
+    last_uip_ext_len = uip_ext_len;
+    uip_ext_len = 0;
+    UIP_IP_BUF->proto = UIP_EXT_BUF->next;
+    memmove(((uint8_t *)UIP_TCP_BUF), (uint8_t *)UIP_TCP_BUF + last_uip_ext_len,
+	    uip_len - UIP_IPH_LEN - last_uip_ext_len);
 
-    uip_len -= uip_ext_len;
+    uip_len -= last_uip_ext_len;
 
     /* Update the IP length. */
     UIP_IP_BUF->len[0] = (uip_len - UIP_IPH_LEN) >> 8;
     UIP_IP_BUF->len[1] = (uip_len - UIP_IPH_LEN) & 0xff;
-    uip_ext_len = 0;
   }
 }
 /*---------------------------------------------------------------------------*/
@@ -1494,7 +1497,6 @@ uip_process(uint8_t flag)
   udp_input:
 
   remove_ext_hdr();
-  UIP_IP_BUF->proto = UIP_PROTO_UDP;
 
   LOG_INFO("Receiving UDP packet\n");
 
@@ -1607,7 +1609,6 @@ uip_process(uint8_t flag)
   tcp_input:
 
   remove_ext_hdr();
-  UIP_IP_BUF->proto = UIP_PROTO_TCP;
 
   UIP_STAT(++uip_stat.tcp.recv);
   LOG_INFO("Receiving TCP packet\n");
diff --git a/os/net/rpl-classic/rpl-dag.c b/os/net/rpl-classic/rpl-dag.c
index 4649f31e7..aeed6194e 100644
--- a/os/net/rpl-classic/rpl-dag.c
+++ b/os/net/rpl-classic/rpl-dag.c
@@ -764,22 +764,17 @@ rpl_select_dag(rpl_instance_t *instance, rpl_parent_t *p)
   old_rank = instance->current_dag->rank;
   last_parent = instance->current_dag->preferred_parent;
 
-  best_dag = instance->current_dag;
-  if(best_dag->rank != ROOT_RANK(instance)) {
-    if(rpl_select_parent(p->dag) != NULL) {
-      if(p->dag != best_dag) {
-        best_dag = instance->of->best_dag(best_dag, p->dag);
-      }
-    } else if(p->dag == best_dag) {
-      best_dag = NULL;
-      for(dag = &instance->dag_table[0], end = dag + RPL_MAX_DAG_PER_INSTANCE; dag < end; ++dag) {
-        if(dag->used && dag->preferred_parent != NULL && dag->preferred_parent->rank != RPL_INFINITE_RANK) {
-          if(best_dag == NULL) {
-            best_dag = dag;
-          } else {
-            best_dag = instance->of->best_dag(best_dag, dag);
-          }
-        }
+  if(instance->current_dag->rank != ROOT_RANK(instance)) {
+    rpl_select_parent(p->dag);
+  }
+
+  best_dag = NULL;
+  for(dag = &instance->dag_table[0], end = dag + RPL_MAX_DAG_PER_INSTANCE; dag < end; ++dag) {
+    if(dag->used && dag->preferred_parent != NULL && dag->preferred_parent->rank != RPL_INFINITE_RANK) {
+      if(best_dag == NULL) {
+        best_dag = dag;
+      } else {
+        best_dag = instance->of->best_dag(best_dag, dag);
       }
     }
   }
diff --git a/os/net/rpl-classic/rpl-ext-header.c b/os/net/rpl-classic/rpl-ext-header.c
index 0c1f8076a..a0fdb0eb4 100644
--- a/os/net/rpl-classic/rpl-ext-header.c
+++ b/os/net/rpl-classic/rpl-ext-header.c
@@ -408,7 +408,7 @@ insert_srh_header(void)
       path_len, cmpri, cmpre, ext_len, padding);
 
   /* Check if there is enough space to store the extension header */
-  if(uip_len + ext_len > UIP_BUFSIZE) {
+  if(uip_len + ext_len > UIP_BUFSIZE - UIP_LLH_LEN) {
     PRINTF("RPL: Packet too long: impossible to add source routing header (%u bytes)\n", ext_len);
     return 0;
   }
@@ -553,7 +553,7 @@ insert_hbh_header(const rpl_instance_t *instance)
 
   /* Insert hop-by-hop header */
   PRINTF("RPL: Creating hop-by-hop option\n");
-  if(uip_len + RPL_HOP_BY_HOP_LEN > UIP_BUFSIZE) {
+  if(uip_len + RPL_HOP_BY_HOP_LEN > UIP_BUFSIZE - UIP_LLH_LEN) {
     PRINTF("RPL: Packet too long: impossible to add hop-by-hop option\n");
     uip_ext_len = last_uip_ext_len;
     return 0;
diff --git a/os/net/rpl-classic/rpl-ns.h b/os/net/rpl-classic/rpl-ns.h
index f6ae4c2c6..dcc7e584a 100644
--- a/os/net/rpl-classic/rpl-ns.h
+++ b/os/net/rpl-classic/rpl-ns.h
@@ -56,6 +56,7 @@
 typedef struct rpl_ns_node {
   struct rpl_ns_node *next;
   uint32_t lifetime;
+  rpl_dag_t *dag;
   /* Store only IPv6 link identifiers as all nodes in the DAG share the same prefix */
   unsigned char link_identifier[8];
   struct rpl_ns_node *parent;
diff --git a/os/net/rpl-classic/rpl-timers.c b/os/net/rpl-classic/rpl-timers.c
index 56eda7abc..7742a5fcc 100644
--- a/os/net/rpl-classic/rpl-timers.c
+++ b/os/net/rpl-classic/rpl-timers.c
@@ -457,11 +457,29 @@ get_probing_target(rpl_dag_t *dag)
   return probing_target;
 }
 /*---------------------------------------------------------------------------*/
+static rpl_dag_t *
+get_next_dag(rpl_instance_t *instance)
+{
+  rpl_dag_t *dag = NULL;
+  int new_dag = instance->last_dag;
+  do {
+    new_dag++;
+    if(new_dag >= RPL_MAX_DAG_PER_INSTANCE) {
+      new_dag = 0;
+    }
+    if(instance->dag_table[new_dag].used) {
+      dag = &instance->dag_table[new_dag];
+    }
+  } while(new_dag != instance->last_dag && dag == NULL);
+  instance->last_dag = new_dag;
+  return dag;
+}
+/*---------------------------------------------------------------------------*/
 static void
 handle_probing_timer(void *ptr)
 {
   rpl_instance_t *instance = (rpl_instance_t *)ptr;
-  rpl_parent_t *probing_target = RPL_PROBING_SELECT_FUNC(instance->current_dag);
+  rpl_parent_t *probing_target = RPL_PROBING_SELECT_FUNC(get_next_dag(instance));
   uip_ipaddr_t *target_ipaddr = rpl_parent_get_ipaddr(probing_target);
 
   /* Perform probing */
diff --git a/os/net/rpl-classic/rpl.h b/os/net/rpl-classic/rpl.h
index 185bcbef2..2fe9f1dbf 100644
--- a/os/net/rpl-classic/rpl.h
+++ b/os/net/rpl-classic/rpl.h
@@ -252,6 +252,7 @@ struct rpl_instance {
 #if RPL_WITH_PROBING
   struct ctimer probing_timer;
   rpl_parent_t *urgent_probing_target;
+  int last_dag;
 #endif /* RPL_WITH_PROBING */
   struct ctimer dio_timer;
   struct ctimer dao_timer;
diff --git a/os/net/rpl-lite/rpl-ext-header.c b/os/net/rpl-lite/rpl-ext-header.c
index e71e6c1f6..96455e85c 100644
--- a/os/net/rpl-lite/rpl-ext-header.c
+++ b/os/net/rpl-lite/rpl-ext-header.c
@@ -302,7 +302,7 @@ insert_srh_header(void)
       path_len, cmpri, cmpre, ext_len, padding);
 
   /* Check if there is enough space to store the extension header */
-  if(uip_len + ext_len > UIP_BUFSIZE) {
+  if(uip_len + ext_len > UIP_BUFSIZE - UIP_LLH_LEN) {
     LOG_ERR("packet too long: impossible to add source routing header (%u bytes)\n", ext_len);
     return 0;
   }
@@ -464,7 +464,7 @@ insert_hbh_header(void)
 
   /* Insert hop-by-hop header */
   LOG_INFO("creating hop-by-hop option\n");
-  if(uip_len + RPL_HOP_BY_HOP_LEN > UIP_BUFSIZE) {
+  if(uip_len + RPL_HOP_BY_HOP_LEN > UIP_BUFSIZE - UIP_LLH_LEN) {
     LOG_ERR("packet too long: impossible to add hop-by-hop option\n");
     uip_ext_len = last_uip_ext_len;
     return 0;
diff --git a/os/services/ip64/ip64-dhcpc.c b/os/services/ip64/ip64-dhcpc.c
index 81d97490d..8e8e286f8 100644
--- a/os/services/ip64/ip64-dhcpc.c
+++ b/os/services/ip64/ip64-dhcpc.c
@@ -61,7 +61,7 @@ struct dhcp_msg {
   uint8_t options[312];
 };
 
-#if (UIP_BUFSIZE - UIP_UDPIP_HLEN) < 548
+#if (UIP_BUFSIZE - UIP_LLH_LEN - UIP_UDPIP_HLEN) < 548
 #error UIP_CONF_BUFFER_SIZE may be too small to accomodate DHCPv4 packets
 #error Increase UIP_CONF_BUFFER_SIZE in your project-conf.h, or contiki-conf.h
 #error A good size is 600 bytes