Merge branch 'sverker/re-enable-big-creation/OTP-15603'

* sverker/re-enable-big-creation/OTP-15603:
  doc: Add links between dist flags and external tags (DTD updated)
  erts: Fix docs for new pid,port,ref external tags
  erts: Document new EPMD response ALIVE2_X_RESP
  erl_interface: Support 32-bit creation local cnode
  jinterface: Remove old encoding of pid,port,refs
  epmd: Support 32-bit creation values in local node
  erl_interface: Remove old encoding of pid,port,refs
  erts: Remove old encoding of pids, ports and refs
  erts: Make DFLAG_BIG_CREATION mandatory

32 files changed, 312 insertions, 294 deletions

diff --git a/erts/doc/src/erl_dist_protocol.xml b/erts/doc/src/erl_dist_protocol.xml
index f924c8a70b..0c1100d394 100644
--- a/erts/doc/src/erl_dist_protocol.xml
+++ b/erts/doc/src/erl_dist_protocol.xml
@@ -109,7 +109,8 @@
       <title>Register a Node in EPMD</title>
       <p>When a distributed node is started it registers itself in the EPMD.
         The message <c>ALIVE2_REQ</c> described below is sent from the node to
-        the EPMD. The response from the EPMD is <c>ALIVE2_RESP</c>.</p>
+        the EPMD. The response from the EPMD is <c>ALIVE2_X_RESP</c> (or
+        <c>ALIVE2_RESP</c>).</p>
 
       <table align="left">
         <row>
@@ -155,12 +156,12 @@
         <tag><c>HighestVersion</c></tag>
         <item>
           <p>The highest distribution version that this node can handle.
-            The value in Erlang/OTP R6B and later is 5.</p>
+            The value in OTP 23 and later is 6.</p>
         </item>
         <tag><c>LowestVersion</c></tag>
         <item>
           <p>The lowest distribution version that this node can handle.
-            The value in Erlang/OTP R6B and later is 5.</p>
+            The value in OTP 23 and later is 5.</p>
         </item>
         <tag><c>Nlen</c></tag>
         <item>
@@ -184,7 +185,24 @@
         node is a distributed node. When the connection is closed,
         the node is automatically unregistered from the EPMD.</p>
 
-      <p>The response message <c>ALIVE2_RESP</c> is as follows:</p>
+      <p>The response message is either <c>ALIVE2_X_RESP</c> or
+        <c>ALIVE2_RESP</c> depending on distribution version. If both the node
+        and EPMD support distribution version 6 then response is
+        <c>ALIVE2_X_RESP</c> otherwise it is the older <c>ALIVE2_RESP</c>:</p>
+
+      <table align="left">
+        <row>
+          <cell align="center">1</cell>
+          <cell align="center">1</cell>
+          <cell align="center">4</cell>
+        </row>
+        <row>
+          <cell align="center"><c>118</c></cell>
+          <cell align="center"><c>Result</c></cell>
+          <cell align="center"><c>Creation</c></cell>
+        </row>
+        <tcaption>ALIVE2_X_RESP (118) with 32 bit creation</tcaption>
+      </table>
 
       <table align="left">
         <row>
@@ -197,7 +215,7 @@
           <cell align="center"><c>Result</c></cell>
           <cell align="center"><c>Creation</c></cell>
         </row>
-        <tcaption>ALIVE2_RESP (121)</tcaption>
+        <tcaption>ALIVE2_RESP (121) with 16-bit creation</tcaption>
       </table>
 
       <p>Result = 0 -> ok, result &gt; 0 -> error.</p>
@@ -793,7 +811,8 @@ DiB == gen_digest(ChA, ICA)?
         </item>
         <tag><c>-define(DFLAG_NEW_FUN_TAGS,16#80).</c></tag>
         <item>
-          <p>The node understand new fun tags.</p>
+	  <p>The node understands the <seealso marker="erl_ext_dist#NEW_FUN_EXT">
+	    <c>NEW_FUN_EXT</c></seealso> tag.</p>
         </item>
         <tag><c>-define(DFLAG_EXTENDED_PIDS_PORTS,16#100).</c></tag>
         <item>
@@ -802,13 +821,18 @@ DiB == gen_digest(ChA, ICA)?
         </item>
         <tag><c>-define(DFLAG_EXPORT_PTR_TAG,16#200).</c></tag>
         <item>
+	  <p>The node understands the <seealso marker="erl_ext_dist#EXPORT_EXT">
+	    <c>EXPORT_EXT</c></seealso> tag.</p>
         </item>
         <tag><c>-define(DFLAG_BIT_BINARIES,16#400).</c></tag>
         <item>
+	  <p>The node understands the <seealso marker="erl_ext_dist#BIT_BINARY_EXT">
+	    <c>BIT_BINARY_EXT</c></seealso> tag.</p>
         </item>
         <tag><c>-define(DFLAG_NEW_FLOATS,16#800).</c></tag>
         <item>
-          <p>The node understands new float format.</p>
+	  <p>The node understands the <seealso marker="erl_ext_dist#NEW_FLOAT_EXT">
+	    <c>NEW_FLOAT_EXT</c></seealso> tag.</p>
         </item>
         <tag><c>-define(DFLAG_UNICODE_IO,16#1000).</c></tag>
         <item>
@@ -817,21 +841,34 @@ DiB == gen_digest(ChA, ICA)?
         <item>
           <p>The node implements atom cache in distribution header.</p>
         </item>
+	<marker id="DFLAG_SMALL_ATOM_TAGS"/>
         <tag><c>-define(DFLAG_SMALL_ATOM_TAGS, 16#4000).</c></tag>
         <item>
-          <p>The node understand the <c>SMALL_ATOM_EXT</c> tag.</p>
+          <p>The node understands the <seealso marker="erl_ext_dist#SMALL_ATOM_EXT">
+	  <c>SMALL_ATOM_EXT</c></seealso> tag.</p>
         </item>
+	<marker id="DFLAG_UTF8_ATOMS"/>
         <tag><c>-define(DFLAG_UTF8_ATOMS, 16#10000).</c></tag>
         <item>
-          <p>The node understand UTF-8 encoded atoms.</p>
+          <p>The node understands UTF-8 atoms encoded with
+	    <seealso marker="erl_ext_dist#ATOM_UTF8_EXT">
+	    <c>ATOM_UTF8_EXT</c></seealso> and
+	    <seealso marker="erl_ext_dist#SMALL_ATOM_UTF8_EXT">
+	    <c>SMALL ATOM_UTF8_EXT</c></seealso>.</p>
         </item>
         <tag><c>-define(DFLAG_MAP_TAG, 16#20000).</c></tag>
         <item>
-          <p>The node understand the map tag.</p>
+          <p>The node understands the map tag
+	  <seealso marker="erl_ext_dist#MAP_EXT"><c>MAP_EXT</c></seealso>.</p>
         </item>
+	<marker id="DFLAG_BIG_CREATION"/>
         <tag><c>-define(DFLAG_BIG_CREATION, 16#40000).</c></tag>
         <item>
-          <p>The node understand big node creation.</p>
+          <p>The node understands big node creation tags
+	  <seealso marker="erl_ext_dist#NEW_PID_EXT"><c>NEW_PID_EXT</c></seealso>,
+	  <seealso marker="erl_ext_dist#NEW_PORT_EXT"><c>NEW_PORT_EXT</c></seealso> and
+	  <seealso marker="erl_ext_dist#NEWER_REFERENCE_EXT"><c>NEWER_REFERENCE_EXT</c></seealso>.
+	  </p>
         </item>
         <tag><c>-define(DFLAG_SEND_SENDER, 16#80000).</c></tag>
         <item>
@@ -855,6 +892,7 @@ DiB == gen_digest(ChA, ICA)?
             <seealso marker="#control_message">control message</seealso>s
             instead of the non-PAYLOAD variants.</p>
         </item>
+	<marker id="DFLAG_FRAGMENTS"/>
         <tag><c>-define(DFLAG_FRAGMENTS, 16#800000).</c></tag>
         <item>
           <p>Use <seealso marker="erl_ext_dist#fragments">fragmented</seealso>
diff --git a/erts/doc/src/erl_ext_dist.xml b/erts/doc/src/erl_ext_dist.xml
index 2ba5994557..c5b2ce1a0a 100644
--- a/erts/doc/src/erl_ext_dist.xml
+++ b/erts/doc/src/erl_ext_dist.xml
@@ -264,7 +264,7 @@
         consists of. Length is a 2 byte big-endian integer
         if flag <c>LongAtoms</c> has been set, otherwise a 1 byte
         integer. When distribution flag
-        <seealso marker="erl_dist_protocol#dflags">
+        <seealso marker="erl_dist_protocol#DFLAG_UTF8_ATOMS">
         <c>DFLAG_UTF8_ATOMS</c></seealso>
         has been exchanged between both nodes in the
         <seealso marker="erl_dist_protocol#distribution_handshake">
@@ -316,8 +316,8 @@
       </p>
       <p>Fragmented distribution messages are only used if the receiving node
       signals that it supports them via the
-      <seealso marker="erl_dist_protocol#dflags">DFLAG_FRAGMENTS</seealso> distribution
-      flag.</p>
+      <seealso marker="erl_dist_protocol#DFLAG_FRAGMENTS">DFLAG_FRAGMENTS</seealso>
+      distribution flag.</p>
       <p>A process must complete the sending of a fragmented message before it
       can start sending any other message on the same distribution channel.</p>
 
@@ -637,11 +637,14 @@
 	  <seealso marker="#NEW_PID_EXT"><c>NEW_PID_EXT</c></seealso>.
 	  Port operations are not allowed across node boundaries.
 	</p>
-	<p>Introduced in OTP 19, but only to be decoded and echoed back. Not
-	  encoded for local ports. Planned to supersede <seealso marker="#PORT_EXT">
-	  <c>PORT_EXT</c></seealso> in OTP 23 when
-	  <seealso marker="erl_dist_protocol#dflags"><c>DFLAG_BIG_CREATON</c></seealso>
-	  becomes mandatory.
+	<p><c>NEW_PORT_EXT</c> was introduced in OTP 19, but only to be decoded
+	  and echoed back. Not encoded for local ports.
+	</p>
+	<p>In OTP 23 distribution flag
+	  <seealso marker="erl_dist_protocol#DFLAG_BIG_CREATION"><c>DFLAG_BIG_CREATION</c></seealso>
+	  became mandatory. All ports are now
+	  encoded using <c>NEW_PORT_EXT</c>, even external ports received as <seealso
+	  marker="#PORT_EXT"><c>PORT_EXT</c></seealso> from older nodes.
 	</p>
     </section>
 
@@ -719,11 +722,14 @@
 	    erlang:list_to_pid/1</seealso>).</p>
 	  </item>
 	</taglist>
-	<p>Introduced in OTP 19, but only to be decoded and echoed back. Not
-	  encoded for local processes. Planned to supersede <seealso marker="#PID_EXT">
-	  <c>PID_EXT</c></seealso> in OTP 23 when
-	  <seealso marker="erl_dist_protocol#dflags"><c>DFLAG_BIG_CREATON</c></seealso>
-	  becomes mandatory.
+	<p><c>NEW_PID_EXT</c> was introduced in OTP 19, but only to be decoded
+	  and echoed back. Not encoded for local processes.
+	</p>
+	<p>In OTP 23 distribution flag
+	  <seealso marker="erl_dist_protocol#DFLAG_BIG_CREATION"><c>DFLAG_BIG_CREATION</c></seealso>
+	  became mandatory. All pids are now encoded using <c>NEW_PID_EXT</c>,
+	  even external pids received as
+	  <seealso marker="#PID_EXT"><c>PID_EXT</c></seealso> from older nodes.
 	</p>
     </section>
 
@@ -1047,11 +1053,15 @@
 	  <seealso marker="#NEW_PID_EXT"><c>NEW_PID_EXT</c></seealso>.</p>
 	  </item>
 	</taglist>
-	<p>Introduced in OTP 19, but only to be decoded and echoed back. Not
-	  encoded for local references. Planned to supersede <seealso marker="#NEW_REFERENCE_EXT">
-	  <c>NEW_REFERENCE_EXT</c></seealso> in OTP 23 when
-	  <seealso marker="erl_dist_protocol#dflags"><c>DFLAG_BIG_CREATON</c></seealso>
-	  becomes mandatory.
+	<p><c>NEWER_REFERENCE_EXT</c> was introduced in OTP 19, but only to be decoded
+	  and echoed back. Not encoded for local references.
+	</p>
+	<p>In OTP 23 distribution flag
+	  <seealso marker="erl_dist_protocol#DFLAG_BIG_CREATION"><c>DFLAG_BIG_CREATION</c></seealso>
+	  became mandatory. All references are now encoded using
+	  <c>NEWER_REFERENCE_EXT</c>, even external references received as
+	  <seealso marker="#NEW_REFERENCE_EXT"><c>NEW_REFERENCE_EXT</c></seealso>
+	  from older nodes.
 	</p>
     </section>
 
@@ -1408,7 +1418,7 @@
 	<p>
 	  <c>SMALL_ATOM_EXT</c> was introduced in ERTS 5.7.2 and
 	  require an exchange of distribution flag
-	  <seealso marker="erl_dist_protocol#dflags">
+	  <seealso marker="erl_dist_protocol#DFLAG_SMALL_ATOM_TAGS">
 	  <c>DFLAG_SMALL_ATOM_TAGS</c></seealso> in the
 	  <seealso marker="erl_dist_protocol#distribution_handshake">
 	  distribution handshake</seealso>.
diff --git a/erts/doc/src/erl_ext_fig.gif b/erts/doc/src/erl_ext_fig.gif
index 14d6bbc871..40dd17bd5e 100644
--- a/erts/doc/src/erl_ext_fig.gif
+++ b/erts/doc/src/erl_ext_fig.gif
diff --git a/erts/emulator/beam/bif.c b/erts/emulator/beam/bif.c
index dd04018ce6..9f67f46b31 100644
--- a/erts/emulator/beam/bif.c
+++ b/erts/emulator/beam/bif.c
@@ -1915,7 +1915,7 @@ do_send(Process *p, Eterm to, Eterm msg, Eterm return_term, Eterm *refp,
 	    erts_dsprintf_buf_t *dsbufp = erts_create_logger_dsbuf();
 	    erts_dsprintf(dsbufp,
 			  "Discarding message %T from %T to %T in an old "
-			  "incarnation (%d) of this node (%d)\n",
+			  "incarnation (%u) of this node (%u)\n",
 			  msg,
 			  p->common.id,
 			  to,
@@ -1959,7 +1959,7 @@ do_send(Process *p, Eterm to, Eterm msg, Eterm return_term, Eterm *refp,
 	erts_dsprintf_buf_t *dsbufp = erts_create_logger_dsbuf();
 	erts_dsprintf(dsbufp,
 		      "Discarding message %T from %T to %T in an old "
-		      "incarnation (%d) of this node (%d)\n",
+		      "incarnation (%u) of this node (%u)\n",
 		      msg,
 		      p->common.id,
 		      to,
diff --git a/erts/emulator/beam/big.c b/erts/emulator/beam/big.c
index 522f50287a..7666f23a4f 100644
--- a/erts/emulator/beam/big.c
+++ b/erts/emulator/beam/big.c
@@ -2176,6 +2176,24 @@ term_to_Uint64(Eterm term, Uint64 *up)
 #endif
 }
 
+int
+term_to_Uint32(Eterm term, Uint32 *up)
+{
+#if ERTS_SIZEOF_ETERM == 4
+    return term_to_Uint(term,up);
+#else
+    if (is_small(term)) {
+	Sint i = signed_val(term);
+	if (i >= 0) {
+            *up = (Uint32) i;
+            return 1;
+        }
+    }
+    *up = BADARG;
+    return 0;
+#endif
+}
+
 
 int term_to_Sint(Eterm term, Sint *sp)
 {
diff --git a/erts/emulator/beam/big.h b/erts/emulator/beam/big.h
index ad19cce395..3fed076419 100644
--- a/erts/emulator/beam/big.h
+++ b/erts/emulator/beam/big.h
@@ -168,6 +168,8 @@ Eterm erts_uint64_array_to_big(Uint **, int, int, Uint64 *);
 int term_to_Uint64(Eterm, Uint64*);
 int term_to_Sint64(Eterm, Sint64*);
 #endif
+int term_to_Uint32(Eterm, Uint32*);
+
 
 Uint32 big_to_uint32(Eterm b);
 int term_equals_2pow32(Eterm);
diff --git a/erts/emulator/beam/dist.c b/erts/emulator/beam/dist.c
index 6bf866eac9..83ef10cbec 100644
--- a/erts/emulator/beam/dist.c
+++ b/erts/emulator/beam/dist.c
@@ -3774,12 +3774,10 @@ int distribution_info(fmtfn_t to, void *arg)	/* Called by break handler */
 BIF_RETTYPE setnode_2(BIF_ALIST_2)
 {
     Process *net_kernel;
-    Uint creation;
+    Uint32 creation;
 
     /* valid creation ? */
-    if(!term_to_Uint(BIF_ARG_2, &creation))
-	goto error;
-    if(creation > 3)
+    if(!term_to_Uint32(BIF_ARG_2, &creation))
 	goto error;
 
     /* valid node name ? */
@@ -3823,7 +3821,7 @@ BIF_RETTYPE setnode_2(BIF_ALIST_2)
     erts_proc_unlock(BIF_P, ERTS_PROC_LOCK_MAIN);
     erts_thr_progress_block();
     inc_no_nodes();
-    erts_set_this_node(BIF_ARG_1, (Uint32) creation);
+    erts_set_this_node(BIF_ARG_1, creation);
     erts_is_alive = 1;
     send_nodes_mon_msgs(NULL, am_nodeup, BIF_ARG_1, am_visible, NIL);
     erts_thr_progress_unblock();
diff --git a/erts/emulator/beam/dist.h b/erts/emulator/beam/dist.h
index 067028634b..f953a2ab8c 100644
--- a/erts/emulator/beam/dist.h
+++ b/erts/emulator/beam/dist.h
@@ -54,11 +54,12 @@
 #define DFLAG_DIST_MANDATORY (DFLAG_EXTENDED_REFERENCES         \
                               | DFLAG_EXTENDED_PIDS_PORTS       \
 			      | DFLAG_UTF8_ATOMS                \
-			      | DFLAG_NEW_FUN_TAGS)
+			      | DFLAG_NEW_FUN_TAGS              \
+                              | DFLAG_BIG_CREATION)
 
 /*
  * Additional optimistic flags when encoding toward pending connection.
- * If remote node (erl_interface) does not supporting these then we may need
+ * If remote node (erl_interface) does not support these then we may need
  * to transcode messages enqueued before connection setup was finished.
  */
 #define DFLAG_DIST_HOPEFULLY (DFLAG_EXPORT_PTR_TAG              \
@@ -75,7 +76,6 @@
                             | DFLAG_SMALL_ATOM_TAGS           \
                             | DFLAG_UTF8_ATOMS                \
                             | DFLAG_MAP_TAG                   \
-                            | DFLAG_BIG_CREATION              \
                             | DFLAG_SEND_SENDER               \
                             | DFLAG_BIG_SEQTRACE_LABELS       \
                             | DFLAG_EXIT_PAYLOAD              \
diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index 0339589b79..aa55bdab6a 100644
--- a/erts/emulator/beam/erl_bif_info.c
+++ b/erts/emulator/beam/erl_bif_info.c
@@ -2799,7 +2799,10 @@ BIF_RETTYPE system_info_1(BIF_ALIST_1)
     } else if (BIF_ARG_1 == am_threads) {
 	return am_true;
     } else if (BIF_ARG_1 == am_creation) {
-	return make_small(erts_this_node->creation);
+        Uint hsz = 0;
+        erts_bld_uint(NULL, &hsz, erts_this_node->creation);
+        hp = hsz ? HAlloc(BIF_P, hsz) : NULL;
+        BIF_RET(erts_bld_uint(&hp, NULL, erts_this_node->creation));
     } else if (BIF_ARG_1 == am_break_ignored) {
       extern int ignore_break;
       if (ignore_break) 
diff --git a/erts/emulator/beam/erl_node_tables.c b/erts/emulator/beam/erl_node_tables.c
index 4eb6c3e214..11df871763 100644
--- a/erts/emulator/beam/erl_node_tables.c
+++ b/erts/emulator/beam/erl_node_tables.c
@@ -976,7 +976,7 @@ static void print_node(void *venp, void *vpndp)
 	if(pndp->sysname == NIL) {
 	    erts_print(pndp->to, pndp->to_arg, "Name: %T ", enp->sysname);
 	}
-	erts_print(pndp->to, pndp->to_arg, " %d", enp->creation);
+	erts_print(pndp->to, pndp->to_arg, " %u", enp->creation);
 #ifdef DEBUG
 	erts_print(pndp->to, pndp->to_arg, " (refc=%ld)",
 		   erts_refc_read(&enp->refc, 0));
@@ -1019,7 +1019,7 @@ void erts_print_node_info(fmtfn_t to,
 /* ----------------------------------------------------------------------- */
 
 void
-erts_set_this_node(Eterm sysname, Uint creation)
+erts_set_this_node(Eterm sysname, Uint32 creation)
 {
     ERTS_LC_ASSERT(erts_thr_progress_is_blocking());
     ASSERT(2 <= de_refc_read(erts_this_dist_entry, 2));
diff --git a/erts/emulator/beam/erl_node_tables.h b/erts/emulator/beam/erl_node_tables.h
index aa8af12555..fc3e117463 100644
--- a/erts/emulator/beam/erl_node_tables.h
+++ b/erts/emulator/beam/erl_node_tables.h
@@ -259,7 +259,7 @@ void erts_set_dist_entry_pending(DistEntry *);
 void erts_set_dist_entry_connected(DistEntry *, Eterm, Uint);
 ErlNode *erts_find_or_insert_node(Eterm, Uint32, Eterm);
 void erts_schedule_delete_node(ErlNode *);
-void erts_set_this_node(Eterm, Uint);
+void erts_set_this_node(Eterm, Uint32);
 Uint erts_node_table_size(void);
 void erts_init_node_tables(int);
 void erts_node_table_info(fmtfn_t, void *);
diff --git a/erts/emulator/beam/external.c b/erts/emulator/beam/external.c
index 4156eb8d1e..5cea253ebe 100644
--- a/erts/emulator/beam/external.c
+++ b/erts/emulator/beam/external.c
@@ -51,18 +51,17 @@
 
 #define MAX_STRING_LEN 0xffff
 
-/* MAX value for the creation field in pid, port and reference
-   for the local node and for the current external format.
-
-   Larger creation values than this are allowed in external pid, port and refs
-   encoded with NEW_PID_EXT, NEW_PORT_EXT and NEWER_REFERENCE_EXT.
-   The point here is to prepare for future upgrade to 32-bit creation.
-   OTP-19 (erts-8.0) can handle big creation values from other (newer) nodes,
-   but do not use big creation values for the local node yet,
-   as we still may have to communicate with older nodes.
+/*
+ * MAX value for the creation field in pid, port and reference
+ * for the old PID_EXT, PORT_EXT, REFERENCE_EXT and NEW_REFERENCE_EXT.
+ * Older nodes (OTP 19-22) will send us these so we must be able to decode them.
+ *
+ * From OTP 23 DFLAG_BIG_CREATION is mandatory so this node will always
+ * encode with new big 32-bit creations using NEW_PID_EXT, NEW_PORT_EXT
+ * and NEWER_REFERENCE_EXT.
 */
-#define ERTS_MAX_LOCAL_CREATION (3)
-#define is_valid_creation(Cre) ((unsigned)(Cre) <= ERTS_MAX_LOCAL_CREATION)
+#define ERTS_MAX_TINY_CREATION (3)
+#define is_tiny_creation(Cre) ((unsigned)(Cre) <= ERTS_MAX_TINY_CREATION)
 
 #undef ERTS_DEBUG_USE_DIST_SEP
 #ifdef DEBUG
@@ -2469,7 +2468,8 @@ enc_pid(ErtsAtomCacheMap *acmp, Eterm pid, byte* ep, Uint32 dflags)
     Eterm sysname = ((is_internal_pid(pid) && (dflags & DFLAG_INTERNAL_TAGS))
 		      ? INTERNAL_LOCAL_SYSNAME : pid_node_name(pid));
     Uint32 creation = pid_creation(pid);
-    byte* tagp = ep++;
+
+    *ep++ = NEW_PID_EXT;
 
     /* insert  atom here containing host and sysname  */
     ep = enc_atom(acmp, sysname, ep, dflags);
@@ -2481,15 +2481,8 @@ enc_pid(ErtsAtomCacheMap *acmp, Eterm pid, byte* ep, Uint32 dflags)
     ep += 4;
     put_int32(os, ep);
     ep += 4;
-    if (creation <= ERTS_MAX_LOCAL_CREATION) {
-        *tagp = PID_EXT;
-        *ep++ = creation;
-    } else {
-        ASSERT(is_external_pid(pid));
-        *tagp = NEW_PID_EXT;
-        put_int32(creation, ep);
-        ep += 4;
-    }
+    put_int32(creation, ep);
+    ep += 4;
     return ep;
 }
 
@@ -2609,7 +2602,7 @@ dec_pid(ErtsDistExternal *edep, ErtsHeapFactory* factory, byte* ep,
     if (tag == PID_EXT) {
         cre = get_int8(ep);
         ep += 1;
-        if (!is_valid_creation(cre)) {
+        if (!is_tiny_creation(cre)) {
             return NULL;
         }
     } else {
@@ -2870,25 +2863,18 @@ enc_term_int(TTBEncodeContext* ctx, ErtsAtomCacheMap *acmp, Eterm obj, byte* ep,
 	    Eterm sysname = (((dflags & DFLAG_INTERNAL_TAGS) && is_internal_ref(obj))
 			     ? INTERNAL_LOCAL_SYSNAME : ref_node_name(obj));
             Uint32 creation = ref_creation(obj);
-            byte* tagp = ep++;
 
 	    ASSERT(dflags & DFLAG_EXTENDED_REFERENCES);
 
 	    erts_magic_ref_save_bin(obj);
 
+            *ep++ = NEWER_REFERENCE_EXT;
 	    i = ref_no_numbers(obj);
 	    put_int16(i, ep);
 	    ep += 2;
 	    ep = enc_atom(acmp, sysname, ep, dflags);
-            if (creation <= ERTS_MAX_LOCAL_CREATION) {
-                *tagp = NEW_REFERENCE_EXT;
-                *ep++ = creation;
-            } else {
-                ASSERT(is_external_ref(obj));
-                *tagp = NEWER_REFERENCE_EXT;
-                put_int32(creation, ep);
-                ep += 4;
-            }
+            put_int32(creation, ep);
+            ep += 4;
 	    ref_num = ref_numbers(obj);
 	    for (j = 0; j < i; j++) {
 		put_int32(ref_num[j], ep);
@@ -2901,21 +2887,14 @@ enc_term_int(TTBEncodeContext* ctx, ErtsAtomCacheMap *acmp, Eterm obj, byte* ep,
 	    Eterm sysname = (((dflags & DFLAG_INTERNAL_TAGS) && is_internal_port(obj))
 			     ? INTERNAL_LOCAL_SYSNAME : port_node_name(obj));
             Uint32 creation = port_creation(obj);
-            byte* tagp = ep++;
 
+            *ep++ = NEW_PORT_EXT;
 	    ep = enc_atom(acmp, sysname, ep, dflags);
 	    j = port_number(obj);
 	    put_int32(j, ep);
 	    ep += 4;
-            if (creation <= ERTS_MAX_LOCAL_CREATION) {
-                *tagp = PORT_EXT;
-                *ep++ = creation;
-            } else {
-                ASSERT(is_external_port(obj));
-                *tagp = NEW_PORT_EXT;
-                put_int32(creation, ep);
-                ep += 4;
-            }
+            put_int32(creation, ep);
+            ep += 4;
 	    break;
 	}
 	case LIST_DEF:
@@ -3610,7 +3589,7 @@ dec_term_atom_common:
                 if (tag == PORT_EXT) {
                     cre = get_int8(ep);
                     ep++;
-                    if (!is_valid_creation(cre)) {
+                    if (!is_tiny_creation(cre)) {
                         goto error;
                     }
                 }
@@ -3657,7 +3636,7 @@ dec_term_atom_common:
 
 		cre = get_int8(ep);
 		ep += 1;
-		if (!is_valid_creation(cre)) {
+		if (!is_tiny_creation(cre)) {
 		    goto error;
 		}
 		goto ref_ext_common;
@@ -3671,7 +3650,7 @@ dec_term_atom_common:
 
 		cre = get_int8(ep);
 		ep += 1;
-		if (!is_valid_creation(cre)) {
+		if (!is_tiny_creation(cre)) {
 		    goto error;
 		}
 		r0 = get_int32(ep);
@@ -4334,30 +4313,21 @@ encode_size_struct_int(TTBSizeContext* ctx, ErtsAtomCacheMap *acmp, Eterm obj,
 		result += 1 + 4 + 1 + i;  /* tag,size,sign,digits */
 	    break;
         case EXTERNAL_PID_DEF:
-            if (external_pid_creation(obj) > ERTS_MAX_LOCAL_CREATION)
-                result += 3;
-            /*fall through*/
 	case PID_DEF:
 	    result += (1 + encode_size_struct2(acmp, pid_node_name(obj), dflags) +
-		       4 + 4 + 1);
+		       4 + 4 + 4);
 	    break;
         case EXTERNAL_REF_DEF:
-            if (external_ref_creation(obj) > ERTS_MAX_LOCAL_CREATION)
-                result += 3;
-            /*fall through*/
 	case REF_DEF:
 	    ASSERT(dflags & DFLAG_EXTENDED_REFERENCES);
 	    i = ref_no_numbers(obj);
 	    result += (1 + 2 + encode_size_struct2(acmp, ref_node_name(obj), dflags) +
-		       1 + 4*i);
+		       4 + 4*i);
 	    break;
         case EXTERNAL_PORT_DEF:
-            if (external_port_creation(obj) > ERTS_MAX_LOCAL_CREATION)
-                result += 3;
-            /*fall through*/
         case PORT_DEF:
 	    result += (1 + encode_size_struct2(acmp, port_node_name(obj), dflags) +
-		      4 + 1);
+		      4 + 4);
 	    break;
 	case LIST_DEF: {
 	    int is_str = is_external_string(obj, &m);
diff --git a/erts/epmd/epmd.mk b/erts/epmd/epmd.mk
index b1fd04dc04..f6889a7ff1 100644
--- a/erts/epmd/epmd.mk
+++ b/erts/epmd/epmd.mk
@@ -67,5 +67,5 @@ EPMD_NODE_TYPE=110
 # Distribution format 5 contains the new md5 based handshake.
 
 EPMD_DIST_LOW=5
-EPMD_DIST_HIGH=5
+EPMD_DIST_HIGH=6
 
diff --git a/erts/epmd/src/epmd.h b/erts/epmd/src/epmd.h
index cffcd4ae7a..7332294d3d 100644
--- a/erts/epmd/src/epmd.h
+++ b/erts/epmd/src/epmd.h
@@ -26,6 +26,7 @@
 #define EPMD_ALIVE2_REQ 'x'
 #define EPMD_PORT2_REQ 'z'
 #define EPMD_ALIVE2_RESP 'y'
+#define EPMD_ALIVE2_X_RESP 'v'
 #define EPMD_PORT2_RESP 'w'
 #define EPMD_NAMES_REQ 'n'
 
diff --git a/erts/epmd/src/epmd_int.h b/erts/epmd/src/epmd_int.h
index ed9bbdb8cd..a5156a142e 100644
--- a/erts/epmd/src/epmd_int.h
+++ b/erts/epmd/src/epmd_int.h
@@ -277,6 +277,12 @@ static const struct in6_addr in6addr_loopback =
 #define put_int16(i, s) {((unsigned char*)(s))[0] = ((i) >> 8) & 0xff; \
                         ((unsigned char*)(s))[1] = (i)         & 0xff;}
 
+#define put_int32(i, s) do {((char*)(s))[0] = (char)((i) >> 24) & 0xff;   \
+                            ((char*)(s))[1] = (char)((i) >> 16) & 0xff;   \
+                            ((char*)(s))[2] = (char)((i) >> 8)  & 0xff;   \
+                            ((char*)(s))[3] = (char)(i)         & 0xff;} \
+                        while (0)
+
 #if defined(__GNUC__)
 #  define EPMD_INLINE __inline__
 #elif defined(__WIN32__)
@@ -307,10 +313,10 @@ struct enode {
   int fd;			/* The socket in use */
   unsigned short port;		/* Port number of Erlang node */
   char symname[MAXSYMLEN+1];	/* Name of the Erlang node */
-  short creation;		/* Started as a random number 1..3 */
+  unsigned int cr_counter;	/* Used to generate 'creation' numbers */
   char nodetype;                /* 77 = normal erlang node 72 = hidden (c-node */
   char protocol;                /* 0 = tcp/ipv4 */
-  unsigned short highvsn;       /* 0 = OTP-R3 erts-4.6.x, 1 = OTP-R4 erts-4.7.x*/
+  unsigned short highvsn;       /* 5: creation=1..3, 6: creation=1..(2^32-1)*/
   unsigned short lowvsn;
   int extralen;
   char extra[MAXSYMLEN+1];
diff --git a/erts/epmd/src/epmd_srv.c b/erts/epmd/src/epmd_srv.c
index 3c6f1fbdf4..633ec71e5f 100644
--- a/erts/epmd/src/epmd_srv.c
+++ b/erts/epmd/src/epmd_srv.c
@@ -665,6 +665,21 @@ static int do_accept(EpmdVars *g,int listensock)
     return conn_open(g,msgsock);
 }
 
+static void bump_creation(Node* node)
+{
+    if (++node->cr_counter == 0)
+        node->cr_counter = 1;
+}
+static unsigned int get_creation(Node* node)
+{
+    if (node->highvsn >= 6) {
+        return node->cr_counter;  /* 1..(2^32-1)*/
+    }
+    else {
+        return (node->cr_counter - 1) % 3 + 1;   /* 1..3 */
+    }
+}
+
 /* buf is actually one byte larger than bsize,
    giving place for null termination */
 static void do_request(g, fd, s, buf, bsize)
@@ -706,8 +721,10 @@ static void do_request(g, fd, s, buf, bsize)
 	unsigned char protocol;
 	unsigned short highvsn;
 	unsigned short lowvsn;
+        unsigned int creation;
 	int namelen;
 	int extralen;
+        int replylen;
 	char *name; 
 	char *extra;
 	eport = get_int16(&buf[1]);
@@ -737,17 +754,22 @@ static void do_request(g, fd, s, buf, bsize)
 
 	extra = &buf[11+namelen+2];
 	extra[extralen]='\000';
-	wbuf[0] = EPMD_ALIVE2_RESP;
-	if ((node = node_reg2(g, namelen, name, fd, eport, nodetype, protocol,
-			      highvsn, lowvsn, extralen, extra)) == NULL) {
-	    wbuf[1] = 1; /* error */
-	    put_int16(99, wbuf+2);
-	} else {
-	    wbuf[1] = 0; /* ok */
-	    put_int16(node->creation, wbuf+2);
-	}
+        node = node_reg2(g, namelen, name, fd, eport, nodetype, protocol,
+                         highvsn, lowvsn, extralen, extra);
+        creation = node ? get_creation(node) :  99;
+        wbuf[1] = node ? 0 : 1; /* ok | error */
+        if (highvsn >= 6) {
+            wbuf[0] = EPMD_ALIVE2_X_RESP;
+            put_int32(creation, wbuf+2);
+            replylen = 6;
+        }
+        else {
+            wbuf[0] = EPMD_ALIVE2_RESP;
+            put_int16(creation, wbuf+2);
+            replylen = 4;
+        }
   
-	if (!reply(g, fd, wbuf, 4))
+	if (!reply(g, fd, wbuf, replylen))
 	  {
             node_unreg(g, name);
 	    dbg_tty_printf(g,1,"** failed to send ALIVE2_RESP for \"%s\"",
@@ -1200,8 +1222,8 @@ static int node_unreg(EpmdVars *g,char *name)
   for (; node; prev = &node->next, node = node->next)
     if (is_same_str(node->symname, name))
       {
-	dbg_tty_printf(g,1,"unregistering '%s:%d', port %d",
-		       node->symname, node->creation, node->port);
+	dbg_tty_printf(g,1,"unregistering '%s:%u', port %d",
+		       node->symname, get_creation(node), node->port);
 
 	*prev = node->next;	/* Link out from "reg" list */
 
@@ -1235,8 +1257,8 @@ static int node_unreg_sock(EpmdVars *g,int fd)
   for (; node; prev = &node->next, node = node->next)
     if (node->fd == fd)
       {
-	dbg_tty_printf(g,1,"unregistering '%s:%d', port %d",
-		       node->symname, node->creation, node->port);
+	dbg_tty_printf(g,1,"unregistering '%s:%u', port %d",
+		       node->symname, get_creation(node), node->port);
 
 	*prev = node->next;	/* Link out from "reg" list */
 
@@ -1264,19 +1286,8 @@ static int node_unreg_sock(EpmdVars *g,int fd)
 }
 
 /*
- *  Finding a node slot and a (name,creation) name is a bit tricky.
- *  We try in order
- *
- *  1. If the name was used before and we can reuse that slot but use
- *     a new "creation" digit in the range 1..3.
- *
- *  2. We try to find a new unused slot.
- *
- *  3. We try to use an used slot this isn't used any longer.
- *     FIXME: The criteria for *what* slot to steal should be improved.
- *     Perhaps use the oldest or something.
+ * Register a new node
  */
-
 static Node *node_reg2(EpmdVars *g,
 		       int namelen,
 		       char* name,
@@ -1346,7 +1357,7 @@ static Node *node_reg2(EpmdVars *g,
       }
 
   /* Try to find the name in the used queue so that we
-     can change "creation" number 1..3 */
+     can change "creation" number */
 
   prev = NULL;
 
@@ -1375,9 +1386,8 @@ static Node *node_reg2(EpmdVars *g,
 
 	g->nodes.unreg_count--;
 
-	/* When reusing we change the "creation" number 1..3 */
-
-	node->creation = node->creation % 3 + 1;
+	/* When reusing we change the "creation" number */
+	bump_creation(node);
 
 	break;
       }
@@ -1404,7 +1414,8 @@ static Node *node_reg2(EpmdVars *g,
 	      exit(1);
 	    }
 
-	  node->creation = (current_time(g) % 3) + 1; /* "random" 1-3 */
+	  node->cr_counter = current_time(g); /* "random" */
+          bump_creation(node);
 	}
     }
 
@@ -1423,11 +1434,11 @@ static Node *node_reg2(EpmdVars *g,
   select_fd_set(g, fd);
 
   if (highvsn == 0) {
-    dbg_tty_printf(g,1,"registering '%s:%d', port %d",
-		   node->symname, node->creation, node->port);
+    dbg_tty_printf(g,1,"registering '%s:%u', port %d",
+		   node->symname, get_creation(node), node->port);
   } else {
-    dbg_tty_printf(g,1,"registering '%s:%d', port %d",
-		   node->symname, node->creation, node->port);
+    dbg_tty_printf(g,1,"registering '%s:%u', port %d",
+		   node->symname, get_creation(node), node->port);
     dbg_tty_printf(g,1,"type %d proto %d highvsn %d lowvsn %d",
 		   nodetype, protocol, highvsn, lowvsn);
   }      
@@ -1561,8 +1572,8 @@ static void print_names(EpmdVars *g)
 
   for (node = g->nodes.reg; node; node = node->next)
     {
-      fprintf(stderr,"*****     active name     \"%s#%d\" at port %d, fd = %d\r\n",
-	      node->symname, node->creation, node->port, node->fd);
+      fprintf(stderr,"*****     active name     \"%s#%u\" at port %d, fd = %d\r\n",
+	      node->symname, get_creation(node), node->port, node->fd);
       count ++;
     }
 
@@ -1572,8 +1583,8 @@ static void print_names(EpmdVars *g)
 
   for (node = g->nodes.unreg; node; node = node->next)
     {
-      fprintf(stderr,"*****     old/unused name \"%s#%d\"\r\n",
-	      node->symname, node->creation);
+      fprintf(stderr,"*****     old/unused name \"%s#%u\"\r\n",
+	      node->symname, get_creation(node));
       count ++;
     }
 
diff --git a/erts/test/erl_print_SUITE.erl b/erts/test/erl_print_SUITE.erl
index 463d890688..0a5987df88 100644
--- a/erts/test/erl_print_SUITE.erl
+++ b/erts/test/erl_print_SUITE.erl
@@ -324,6 +324,9 @@ run_case(Config, TestArgs, Fun) ->
 -define(PORT_EXT,            102).
 -define(PID_EXT,             103).
 -define(NEW_REFERENCE_EXT,   114).
+-define(NEW_PID_EXT,         $X).
+-define(NEW_PORT_EXT,        $Y).
+-define(NEWER_REFERENCE_EXT, $Z).
 
 uint32_be(Uint) when is_integer(Uint), 0 =< Uint, Uint < 1 bsl 32 ->
     [(Uint bsr 24) band 16#ff,
@@ -351,13 +354,13 @@ mk_pid({NodeName, Creation}, Number, Serial) when is_atom(NodeName) ->
     mk_pid({atom_to_list(NodeName), Creation}, Number, Serial);
 mk_pid({NodeName, Creation}, Number, Serial) ->
     case catch binary_to_term(list_to_binary([?VERSION_MAGIC,
-                                              ?PID_EXT,
+                                              ?NEW_PID_EXT,
                                               ?ATOM_EXT,
                                               uint16_be(length(NodeName)),
                                               NodeName,
                                               uint32_be(Number),
                                               uint32_be(Serial),
-                                              uint8(Creation)])) of
+                                              uint32_be(Creation)])) of
         Pid when is_pid(Pid) ->
             Pid;
         {'EXIT', {badarg, _}} ->
@@ -370,12 +373,12 @@ mk_port({NodeName, Creation}, Number) when is_atom(NodeName) ->
     mk_port({atom_to_list(NodeName), Creation}, Number);
 mk_port({NodeName, Creation}, Number) ->
     case catch binary_to_term(list_to_binary([?VERSION_MAGIC,
-                                              ?PORT_EXT,
+                                              ?NEW_PORT_EXT,
                                               ?ATOM_EXT,
                                               uint16_be(length(NodeName)),
                                               NodeName,
                                               uint32_be(Number),
-                                              uint8(Creation)])) of
+                                              uint32_be(Creation)])) of
         Port when is_port(Port) ->
             Port;
         {'EXIT', {badarg, _}} ->
@@ -388,33 +391,16 @@ mk_ref({NodeName, Creation}, Numbers) when is_atom(NodeName),
                                            is_integer(Creation),
                                            is_list(Numbers) ->
     mk_ref({atom_to_list(NodeName), Creation}, Numbers);
-mk_ref({NodeName, Creation}, [Number]) when is_list(NodeName),
-                                            is_integer(Creation),
-                                            is_integer(Number) ->
-    case catch binary_to_term(list_to_binary([?VERSION_MAGIC,
-                                              ?REFERENCE_EXT,
-                                              ?ATOM_EXT,
-                                              uint16_be(length(NodeName)),
-                                              NodeName,
-                                              uint32_be(Number),
-                                              uint8(Creation)])) of
-        Ref when is_reference(Ref) ->
-            Ref;
-        {'EXIT', {badarg, _}} ->
-            exit({badarg, mk_ref, [{NodeName, Creation}, [Number]]});
-        Other ->
-            exit({unexpected_binary_to_term_result, Other})
-    end;
 mk_ref({NodeName, Creation}, Numbers) when is_list(NodeName),
                                            is_integer(Creation),
                                            is_list(Numbers) ->
     case catch binary_to_term(list_to_binary([?VERSION_MAGIC,
-                                              ?NEW_REFERENCE_EXT,
+                                              ?NEWER_REFERENCE_EXT,
                                               uint16_be(length(Numbers)),
                                               ?ATOM_EXT,
                                               uint16_be(length(NodeName)),
                                               NodeName,
-                                              uint8(Creation),
+                                              uint32_be(Creation),
                                               lists:map(fun (N) ->
                                                                 uint32_be(N)
                                                         end,
@@ -429,11 +415,10 @@ mk_ref({NodeName, Creation}, Numbers) when is_list(NodeName),
 
 my_cre() -> erlang:system_info(creation).
 
-oth_cre(0) -> 1;
-oth_cre(1) -> 2;
-oth_cre(2) -> 3;
-oth_cre(3) -> 1;
-oth_cre(N) -> exit({invalid_creation, N}).
+oth_cre(N) when N >= 0, N < (1 bsl 32) ->
+    (N rem ((1 bsl 32) - 1)) + 1;
+oth_cre(N) ->
+    exit({invalid_creation, N}).
 
 str_1_bsl_10000() ->
     "19950631168807583848837421626835850838234968318861924548520089498529438830221946631919961684036194597899331129423209124271556491349413781117593785932096323957855730046793794526765246551266059895520550086918193311542508608460618104685509074866089624888090489894838009253941633257850621568309473902556912388065225096643874441046759871626985453222868538161694315775629640762836880760732228535091641476183956381458969463899410840960536267821064621427333394036525565649530603142680234969400335934316651459297773279665775606172582031407994198179607378245683762280037302885487251900834464581454650557929601414833921615734588139257095379769119277800826957735674444123062018757836325502728323789270710373802866393031428133241401624195671690574061419654342324638801248856147305207431992259611796250130992860241708340807605932320161268492288496255841312844061536738951487114256315111089745514203313820202931640957596464756010405845841566072044962867016515061920631004186422275908670900574606417856951911456055068251250406007519842261898059237118054444788072906395242548339221982707404473162376760846613033778706039803413197133493654622700563169937455508241780972810983291314403571877524768509857276937926433221599399876886660808368837838027643282775172273657572744784112294389733810861607423253291974813120197604178281965697475898164531258434135959862784130128185406283476649088690521047580882615823961985770122407044330583075869039319604603404973156583208672105913300903752823415539745394397715257455290510212310947321610753474825740775273986348298498340756937955646638621874569499279016572103701364433135817214311791398222983845847334440270964182851005072927748364550578634501100852987812389473928699540834346158807043959118985815145779177143619698728131459483783202081474982171858011389071228250905826817436220577475921417653715687725614904582904992461028630081535583308130101987675856234343538955409175623400844887526162643568648833519463720377293240094456246923254350400678027273837755376406726898636241037491410966718557050759098100246789880178271925953381282421954028302759408448955014676668389697996886241636313376393903373455801407636741877711055384225739499110186468219696581651485130494222369947714763069155468217682876200362777257723781365331611196811280792669481887201298643660768551639860534602297871557517947385246369446923087894265948217008051120322365496288169035739121368338393591756418733850510970271613915439590991598154654417336311656936031122249937969999226781732358023111862644575299135758175008199839236284615249881088960232244362173771618086357015468484058622329792853875623486556440536962622018963571028812361567512543338303270029097668650568557157505516727518899194129711337690149916181315171544007728650573189557450920330185304847113818315407324053319038462084036421763703911550639789000742853672196280903477974533320468368795868580237952218629120080742819551317948157624448298518461509704888027274721574688131594750409732115080498190455803416826949787141316063210686391511681774304792596709376".
diff --git a/lib/erl_docgen/priv/dtd/common.dtd b/lib/erl_docgen/priv/dtd/common.dtd
index 0ccd52068b..0feb09eac2 100644
--- a/lib/erl_docgen/priv/dtd/common.dtd
+++ b/lib/erl_docgen/priv/dtd/common.dtd
@@ -67,7 +67,7 @@
 
 <!ELEMENT list                (item+) >
 <!ATTLIST list                 type (ordered|bulleted) "bulleted" >
-<!ELEMENT taglist             (tag,item+)+ >
+<!ELEMENT taglist             (marker*,tag,item+)+ >
 <!ELEMENT tag                 (#PCDATA|c|i|em|br|seealso|url|marker|anno)* >
 <!ELEMENT item                (%inline;|%block;|warning|note|dont|do|quote)* >
 
diff --git a/lib/erl_interface/src/connect/ei_connect.c b/lib/erl_interface/src/connect/ei_connect.c
index 1b1479d2e9..f600758385 100644
--- a/lib/erl_interface/src/connect/ei_connect.c
+++ b/lib/erl_interface/src/connect/ei_connect.c
@@ -659,7 +659,7 @@ int ei_connect_xinit_ussi(ei_cnode* ec, const char *thishostname,
         return ERL_ERROR;
     }
     
-    ec->creation = creation & 0x3; /* 2 bits */
+    ec->creation = creation;
     
     if (cookie) {
 	if (strlen(cookie) >= sizeof(ec->ei_connect_cookie)) { 
@@ -698,7 +698,7 @@ int ei_connect_xinit_ussi(ei_cnode* ec, const char *thishostname,
     strcpy(ec->self.node,thisnodename);
     ec->self.num = 0;
     ec->self.serial = 0;
-    ec->self.creation = creation & 0x3; /* 2 bits */
+    ec->self.creation = creation;
 
     ec->cbs = cbs;
     ec->setup_context = setup_context;
diff --git a/lib/erl_interface/src/encode/encode_pid.c b/lib/erl_interface/src/encode/encode_pid.c
index d14746b40f..0dfdb16372 100644
--- a/lib/erl_interface/src/encode/encode_pid.c
+++ b/lib/erl_interface/src/encode/encode_pid.c
@@ -25,7 +25,6 @@
 int ei_encode_pid(char *buf, int *index, const erlang_pid *p)
 {
   char* s = buf + *index;
-  const char tag = (p->creation > 3) ? ERL_NEW_PID_EXT : ERL_PID_EXT;
 
   ++(*index); /* skip ERL_PID_EXT */
   if (ei_encode_atom_len_as(buf, index, p->node, strlen(p->node),
@@ -33,21 +32,17 @@ int ei_encode_pid(char *buf, int *index, const erlang_pid *p)
       return -1;
 
   if (buf) {
-    put8(s, tag);
+    put8(s, ERL_NEW_PID_EXT);
 
     s = buf + *index;
 
     /* now the integers */
     put32be(s,p->num & 0x7fff); /* 15 bits */
     put32be(s,p->serial & 0x1fff); /* 13 bits */
-    if (tag == ERL_PID_EXT) {
-        put8(s,(p->creation & 0x03)); /* 2 bits */
-    } else {
-        put32be(s, p->creation); /* 32 bits */
-    }
+    put32be(s, p->creation); /* 32 bits */
   }
 
-  *index += 4 + 4 + (tag == ERL_PID_EXT ? 1 : 4);
+  *index += 4 + 4 + 4;
   return 0;
 }
 
diff --git a/lib/erl_interface/src/encode/encode_port.c b/lib/erl_interface/src/encode/encode_port.c
index eb464380c0..0fb4018db1 100644
--- a/lib/erl_interface/src/encode/encode_port.c
+++ b/lib/erl_interface/src/encode/encode_port.c
@@ -25,7 +25,6 @@
 int ei_encode_port(char *buf, int *index, const erlang_port *p)
 {
   char *s = buf + *index;
-  const char tag = p->creation > 3 ? ERL_NEW_PORT_EXT : ERL_PORT_EXT;
 
   ++(*index); /* skip ERL_PORT_EXT */
   if (ei_encode_atom_len_as(buf, index, p->node, strlen(p->node), ERLANG_UTF8,
@@ -33,19 +32,15 @@ int ei_encode_port(char *buf, int *index, const erlang_port *p)
       return -1;
   }
   if (buf) {
-    put8(s, tag);
+    put8(s, ERL_NEW_PORT_EXT);
 
     s = buf + *index;
 
     /* now the integers */
     put32be(s,p->id & 0x0fffffff /* 28 bits */);
-    if (tag == ERL_PORT_EXT) {
-        put8(s,(p->creation & 0x03));
-    } else {
-        put32be(s, p->creation);
-    }
+    put32be(s, p->creation);
   }
-  *index += 4 + (tag == ERL_PORT_EXT ? 1 : 4);
+  *index += 4 + 4;
   return 0;
 }
 
diff --git a/lib/erl_interface/src/encode/encode_ref.c b/lib/erl_interface/src/encode/encode_ref.c
index 5ccfc32c6d..8c2e0a25f7 100644
--- a/lib/erl_interface/src/encode/encode_ref.c
+++ b/lib/erl_interface/src/encode/encode_ref.c
@@ -24,7 +24,6 @@
 
 int ei_encode_ref(char *buf, int *index, const erlang_ref *p)
 {
-  const char tag = (p->creation > 3) ? ERL_NEWER_REFERENCE_EXT : ERL_NEW_REFERENCE_EXT;
   char *s = buf + *index;
   int i;
 
@@ -37,7 +36,7 @@ int ei_encode_ref(char *buf, int *index, const erlang_ref *p)
   /* Always encode as an extended reference; all participating parties
      are now expected to be able to decode extended references. */
   if (buf) {
-	  put8(s, tag);
+	  put8(s, ERL_NEWER_REFERENCE_EXT);
 
 	  /* first, number of integers */
 	  put16be(s, p->len);
@@ -46,15 +45,12 @@ int ei_encode_ref(char *buf, int *index, const erlang_ref *p)
 	  s = buf + *index;
 
 	  /* now the integers */
-          if (tag == ERL_NEW_REFERENCE_EXT)
-              put8(s,(p->creation & 0x03));
-          else
-              put32be(s, p->creation);
+          put32be(s, p->creation);
 	  for (i = 0; i < p->len; i++)
 	      put32be(s,p->n[i]);
   }
   
-  *index += p->len*4 + (tag == ERL_NEW_REFERENCE_EXT ? 1 : 4);
+  *index += p->len*4 + 4;
   return 0;
 }
 
diff --git a/lib/erl_interface/src/epmd/ei_epmd.h b/lib/erl_interface/src/epmd/ei_epmd.h
index ac153b6e66..597a955676 100644
--- a/lib/erl_interface/src/epmd/ei_epmd.h
+++ b/lib/erl_interface/src/epmd/ei_epmd.h
@@ -25,8 +25,8 @@
 #endif
 
 #ifndef EI_DIST_HIGH
-#define EI_DIST_HIGH 5 /* R4 and later */
-#define EI_DIST_LOW  1 /* R3 and earlier */
+#define EI_DIST_HIGH 6 /* OTP 23 and later */
+#define EI_DIST_LOW  5 /* OTP R4 - 22 */
 #endif
 
 #ifndef EPMD_PORT
@@ -45,6 +45,7 @@
 #ifndef EI_EPMD_ALIVE2_REQ
 #define EI_EPMD_ALIVE2_REQ  120
 #define EI_EPMD_ALIVE2_RESP 121
+#define EI_EPMD_ALIVE2_X_RESP 118
 #define EI_EPMD_PORT2_REQ   122
 #define EI_EPMD_PORT2_RESP  119
 #define EI_EPMD_STOP_REQ      's'
diff --git a/lib/erl_interface/src/epmd/epmd_publish.c b/lib/erl_interface/src/epmd/epmd_publish.c
index 20b8e867e8..ef8a5d6b70 100644
--- a/lib/erl_interface/src/epmd/epmd_publish.c
+++ b/lib/erl_interface/src/epmd/epmd_publish.c
@@ -68,7 +68,8 @@ static int ei_epmd_r4_publish (int port, const char *alive, unsigned ms)
   int nlen = strlen(alive);
   int len = elen + nlen + 13; /* hard coded: be careful! */
   int n;
-  int err, res, creation;
+  int err, response, res;
+  unsigned creation;
   ssize_t dlen;
   unsigned tmo = ms == 0 ? EI_SCLBK_INF_TMO : ms;
 
@@ -124,8 +125,10 @@ static int ei_epmd_r4_publish (int port, const char *alive, unsigned ms)
 
   /* Don't close fd here! It keeps us registered with epmd */
   s = buf;
-  if (((res=get8(s)) != EI_EPMD_ALIVE2_RESP)) {  /* response */
-    EI_TRACE_ERR1("ei_epmd_r4_publish","<- unknown (%d)",res);
+  response = get8(s);
+  if (response != EI_EPMD_ALIVE2_RESP &&
+      response != EI_EPMD_ALIVE2_X_RESP) {
+    EI_TRACE_ERR1("ei_epmd_r4_publish","<- unknown (%d)",response);
     EI_TRACE_ERR0("ei_epmd_r4_publish","-> CLOSE");
     ei_close__(fd);
     erl_errno = EIO;
@@ -141,18 +144,21 @@ static int ei_epmd_r4_publish (int port, const char *alive, unsigned ms)
     return -1;
   }
 
-  creation = get16be(s);
+  if (response == EI_EPMD_ALIVE2_RESP)
+      creation = get16be(s);
+  else /* EI_EPMD_ALIVE2_X_RESP */
+      creation = get32be(s);
 
   EI_TRACE_CONN2("ei_epmd_r4_publish",
-		 " result=%d (ok) creation=%d",res,creation);
+		 " result=%d (ok) creation=%u",res,creation);
 
-  /* probably should save fd so we can close it later... */
-  /* epmd_saveconn(OPEN,fd,alive); */
+  /*
+   * Would be nice to somehow use the nice "unique" creation value
+   * received here from epmd instead of using the crappy one
+   * passed (already) to ei_connect_init.
+   */
 
-  /* return the creation number, for no good reason */
-  /* return creation;*/
-
-  /* no - return the descriptor */
+  /* return the descriptor */
   return fd;
 }
 
diff --git a/lib/erl_interface/src/prog/erl_call.c b/lib/erl_interface/src/prog/erl_call.c
index ab91157035..dce2ecdec2 100644
--- a/lib/erl_interface/src/prog/erl_call.c
+++ b/lib/erl_interface/src/prog/erl_call.c
@@ -292,8 +292,7 @@ int erl_call(int argc, char **argv)
 	flags.cookie = NULL;
     }
 
-    /* FIXME decide how many bits etc or leave to connect_xinit? */
-    creation = (time(NULL) % 3) + 1; /* "random" */
+    creation = time(NULL) + 1; /* "random" */
 
     if (flags.hidden == NULL) {
       /* As default we are c17@gethostname */
diff --git a/lib/erl_interface/test/erl_eterm_SUITE.erl b/lib/erl_interface/test/erl_eterm_SUITE.erl
index 77910a9fc7..4605293c74 100644
--- a/lib/erl_interface/test/erl_eterm_SUITE.erl
+++ b/lib/erl_interface/test/erl_eterm_SUITE.erl
@@ -73,6 +73,10 @@
 
 -import(runner, [get_term/1]).
 
+-define(REFERENCE_EXT, $e).
+-define(NEW_REFERENCE_EXT, $r).
+-define(NEWER_REFERENCE_EXT, $Z).
+
 %% This test suite controls the running of the C language functions
 %% in eterm_test.c and print_term.c.
 
@@ -1026,9 +1030,11 @@ cnode_1(Config) when is_list(Config) ->
 
 check_ref(Ref) ->
     case bin_ext_type(Ref) of
-        101 ->
+        ?REFERENCE_EXT ->
             ct:fail(oldref);
-        114 ->
+        ?NEW_REFERENCE_EXT ->
+            ok;
+        ?NEWER_REFERENCE_EXT ->
             ok;
         Type ->
             ct:fail({type, Type})
diff --git a/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpErlangPid.java b/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpErlangPid.java
index 9cbd735751..3abdf9535f 100644
--- a/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpErlangPid.java
+++ b/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpErlangPid.java
@@ -27,7 +27,6 @@ public class OtpErlangPid extends OtpErlangObject implements Comparable<Object>
     // don't change this!
     private static final long serialVersionUID = 1664394142301803659L;
 
-    private final int tag;
     private final String node;
     private final int id;
     private final int serial;
@@ -45,7 +44,6 @@ public class OtpErlangPid extends OtpErlangObject implements Comparable<Object>
     public OtpErlangPid(final OtpLocalNode self) {
         final OtpErlangPid p = self.createPid();
 
-	tag = p.tag;
         id = p.id;
         serial = p.serial;
         creation = p.creation;
@@ -67,7 +65,6 @@ public class OtpErlangPid extends OtpErlangObject implements Comparable<Object>
             throws OtpErlangDecodeException {
         final OtpErlangPid p = buf.read_pid();
 
-	tag = p.tag;
         node = p.node();
         id = p.id();
         serial = p.serial();
@@ -118,7 +115,6 @@ public class OtpErlangPid extends OtpErlangObject implements Comparable<Object>
      */
     protected OtpErlangPid(final int tag, final String node, final int id,
 			   final int serial, final int creation) {
-	this.tag = tag;
 	this.node = node;
 	if (tag == OtpExternal.pidTag) {
 	    this.id = id & 0x7fff; // 15 bits
@@ -133,7 +129,7 @@ public class OtpErlangPid extends OtpErlangObject implements Comparable<Object>
     }
 
     protected int tag() {
-	return tag;
+	return OtpExternal.newPidTag;
     }
 
     /**
diff --git a/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpErlangPort.java b/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpErlangPort.java
index 79b5d2736c..c8648d7aa3 100644
--- a/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpErlangPort.java
+++ b/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpErlangPort.java
@@ -26,7 +26,6 @@ public class OtpErlangPort extends OtpErlangObject {
     // don't change this!
     private static final long serialVersionUID = 4037115468007644704L;
 
-    private final int tag;
     private final String node;
     private final int id;
     private final int creation;
@@ -43,7 +42,6 @@ public class OtpErlangPort extends OtpErlangObject {
     private OtpErlangPort(final OtpSelf self) {
         final OtpErlangPort p = self.createPort();
 
-	tag = p.tag;
         id = p.id;
         creation = p.creation;
         node = p.node;
@@ -64,7 +62,6 @@ public class OtpErlangPort extends OtpErlangObject {
             throws OtpErlangDecodeException {
         final OtpErlangPort p = buf.read_port();
 
-	tag = p.tag;
         node = p.node();
         id = p.id();
         creation = p.creation();
@@ -105,7 +102,6 @@ public class OtpErlangPort extends OtpErlangObject {
      */
     public OtpErlangPort(final int tag, final String node, final int id,
 			 final int creation) {
-	this.tag = tag;
 	this.node = node;
 	if (tag == OtpExternal.portTag) {
 	    this.id = id & 0xfffffff; // 28 bits
@@ -118,7 +114,7 @@ public class OtpErlangPort extends OtpErlangObject {
     }
 
     protected int tag() {
-        return tag;
+        return OtpExternal.newPortTag;
     }
 
     /**
diff --git a/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpErlangRef.java b/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpErlangRef.java
index 2165397013..2bf8d9a56b 100644
--- a/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpErlangRef.java
+++ b/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpErlangRef.java
@@ -28,7 +28,6 @@ public class OtpErlangRef extends OtpErlangObject {
     // don't change this!
     private static final long serialVersionUID = -7022666480768586521L;
 
-    private final int tag;
     private final String node;
     private final int creation;
 
@@ -49,7 +48,6 @@ public class OtpErlangRef extends OtpErlangObject {
     public OtpErlangRef(final OtpLocalNode self) {
         final OtpErlangRef r = self.createRef();
 
-	tag = r.tag;
         ids = r.ids;
         creation = r.creation;
         node = r.node;
@@ -70,7 +68,6 @@ public class OtpErlangRef extends OtpErlangObject {
             throws OtpErlangDecodeException {
         final OtpErlangRef r = buf.read_ref();
 
-	tag = r.tag;
         node = r.node();
         creation = r.creation();
 
@@ -90,7 +87,6 @@ public class OtpErlangRef extends OtpErlangObject {
      *            another arbitrary number.
      */
     public OtpErlangRef(final String node, final int id, final int creation) {
-	this.tag = OtpExternal.newRefTag;
         this.node = node;
         ids = new int[1];
         ids[0] = id & 0x3ffff; // 18 bits
@@ -138,7 +134,6 @@ public class OtpErlangRef extends OtpErlangObject {
      */
     public OtpErlangRef(final int tag, final String node, final int[] ids,
 			final int creation) {
-	this.tag = tag;
         this.node = node;
 
         // use at most 3 words
@@ -162,7 +157,7 @@ public class OtpErlangRef extends OtpErlangObject {
     }
 
     protected int tag() {
-        return tag;
+        return OtpExternal.newerRefTag;
     }
 
     /**
diff --git a/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpOutputStream.java b/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpOutputStream.java
index 187705a0b5..a3b089c1da 100644
--- a/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpOutputStream.java
+++ b/lib/jinterface/java_src/com/ericsson/otp/erlang/OtpOutputStream.java
@@ -713,7 +713,7 @@ public class OtpOutputStream extends ByteArrayOutputStream {
      */
     public void write_pid(final String node, final int id, final int serial,
             final int creation) {
-	write1(OtpExternal.pidTag);
+	write1(OtpExternal.newPidTag);
 	write_atom(node);
 	write4BE(id & 0x7fff); // 15 bits
 	write4BE(serial & 0x1fff); // 13 bits
@@ -727,20 +727,11 @@ public class OtpOutputStream extends ByteArrayOutputStream {
      *            the pid
      */
     public void write_pid(OtpErlangPid pid) {
-	write1(pid.tag());
+	write1(OtpExternal.newPidTag);
 	write_atom(pid.node());
 	write4BE(pid.id());
 	write4BE(pid.serial());
-	switch (pid.tag()) {
-	case OtpExternal.pidTag:
-	    write1(pid.creation());
-	    break;
-	case OtpExternal.newPidTag:
-	    write4BE(pid.creation());
-	    break;
-	default:
-	    throw new AssertionError("Invalid pid tag " + pid.tag());
-	}
+        write4BE(pid.creation());
     }
 
 
@@ -758,7 +749,7 @@ public class OtpOutputStream extends ByteArrayOutputStream {
      *            be used.
      */
     public void write_port(final String node, final int id, final int creation) {
-	write1(OtpExternal.portTag);
+	write1(OtpExternal.newPortTag);
 	write_atom(node);
 	write4BE(id & 0xfffffff); // 28 bits
 	write1(creation & 0x3); // 2 bits
@@ -771,19 +762,10 @@ public class OtpOutputStream extends ByteArrayOutputStream {
      *            the port.
      */
     public void write_port(OtpErlangPort port) {
-	write1(port.tag());
+	write1(OtpExternal.newPortTag);
 	write_atom(port.node());
 	write4BE(port.id());
-	switch (port.tag()) {
-	case OtpExternal.portTag:	    
-	    write1(port.creation());
-	    break;
-	case OtpExternal.newPortTag:
-	    write4BE(port.creation());
-	    break;
-	default:
-	    throw new AssertionError("Invalid port tag " + port.tag());
-	}
+        write4BE(port.creation());
     }
 
     /**
@@ -829,7 +811,7 @@ public class OtpOutputStream extends ByteArrayOutputStream {
             arity = 3; // max 3 words in ref
         }
 
-	write1(OtpExternal.newRefTag);
+	write1(OtpExternal.newerRefTag);
 
 	// how many id values
 	write2BE(arity);
@@ -857,24 +839,12 @@ public class OtpOutputStream extends ByteArrayOutputStream {
 	int[] ids = ref.ids();
         int arity = ids.length;
 
-	write1(ref.tag());
+	write1(OtpExternal.newerRefTag);
 	write2BE(arity);
 	write_atom(ref.node());
+        write4BE(ref.creation());
 
-	switch (ref.tag()) {
-	case OtpExternal.newRefTag:
-	    write1(ref.creation());
-	    write4BE(ids[0] & 0x3ffff); // first word gets truncated to 18 bits
-	    break;
-	case OtpExternal.newerRefTag:
-	    write4BE(ref.creation());
-	    write4BE(ids[0]); // full first word
-	    break;
-	default:
-	    throw new AssertionError("Invalid ref tag " + ref.tag());
-	}
-
-	for (int i = 1; i < arity; i++) {
+	for (int i = 0; i < arity; i++) {
 	    write4BE(ids[i]);
 	}
     }
diff --git a/lib/kernel/src/erl_epmd.erl b/lib/kernel/src/erl_epmd.erl
index 7a14e2635c..f31a1722ce 100644
--- a/lib/kernel/src/erl_epmd.erl
+++ b/lib/kernel/src/erl_epmd.erl
@@ -33,10 +33,10 @@
 -define(erlang_daemon_port, 4369).
 -endif.
 -ifndef(epmd_dist_high).
--define(epmd_dist_high, 4370).
+-define(epmd_dist_high, 6).
 -endif.
 -ifndef(epmd_dist_low).
--define(epmd_dist_low, 4370).
+-define(epmd_dist_low, 5).
 -endif.
 
 %% External exports
@@ -342,6 +342,13 @@ wait_for_reg_reply(Socket, SoFar) ->
     receive
 	{tcp, Socket, Data0} ->
 	    case SoFar ++ Data0 of
+		[$v, Result, A, B, C, D] ->
+		    case Result of
+			0 ->
+			    {alive, Socket, ?u32(A, B, C, D)};
+			_ ->
+			    {error, duplicate_name}
+		    end;
 		[$y, Result, A, B] ->
 		    case Result of
 			0 ->
diff --git a/lib/kernel/test/erl_distribution_wb_SUITE.erl b/lib/kernel/test/erl_distribution_wb_SUITE.erl
index 8256444bdc..bb42a0ac39 100644
--- a/lib/kernel/test/erl_distribution_wb_SUITE.erl
+++ b/lib/kernel/test/erl_distribution_wb_SUITE.erl
@@ -47,6 +47,9 @@
 	        R
         end).
 
+-define(EPMD_DIST_HIGH, 6).
+-define(EPMD_DIST_LOW, 5).
+
 -define(DFLAG_PUBLISHED,1).
 -define(DFLAG_ATOM_CACHE,2).
 -define(DFLAG_EXTENDED_REFERENCES,4).
@@ -57,15 +60,18 @@
 -define(DFLAG_NEW_FUN_TAGS,16#80).
 -define(DFLAG_EXTENDED_PIDS_PORTS,16#100).
 -define(DFLAG_UTF8_ATOMS, 16#10000).
+-define(DFLAG_BIG_CREATION, 16#40000).
 
 %% From R9 and forward extended references is compulsory
 %% From R10 and forward extended pids and ports are compulsory
 %% From R20 and forward UTF8 atoms are compulsory
 %% From R21 and forward NEW_FUN_TAGS is compulsory (no more tuple fallback {fun, ...})
+%% From R23 and forward BIG_CREATION is compulsory
 -define(COMPULSORY_DFLAGS, (?DFLAG_EXTENDED_REFERENCES bor
                             ?DFLAG_EXTENDED_PIDS_PORTS bor
                             ?DFLAG_UTF8_ATOMS bor
-                            ?DFLAG_NEW_FUN_TAGS)).
+                            ?DFLAG_NEW_FUN_TAGS bor
+                            ?DFLAG_BIG_CREATION)).
 
 -define(PASS_THROUGH, $p).
 
@@ -208,9 +214,9 @@ pending_up_md5(Node,OurName,Cookie) ->
     {ok, SocketA} = gen_tcp:connect(atom_to_list(NB),PortNo,
 				    [{active,false},
 				     {packet,2}]),
-    send_name(SocketA,OurName,5),
+    send_name(SocketA,OurName, ?EPMD_DIST_HIGH),
     ok = recv_status(SocketA),
-    {hidden,Node,5,HisChallengeA} = recv_challenge(SocketA), % See 1)
+    {hidden,Node,?EPMD_DIST_HIGH,HisChallengeA} = recv_challenge(SocketA), % See 1)
     OurChallengeA = gen_challenge(),
     OurDigestA = gen_digest(HisChallengeA, Cookie),
     send_challenge_reply(SocketA, OurChallengeA, OurDigestA),
@@ -224,11 +230,11 @@ pending_up_md5(Node,OurName,Cookie) ->
     {ok, SocketB} = gen_tcp:connect(atom_to_list(NB),PortNo,
 				    [{active,false},
 				     {packet,2}]),
-    send_name(SocketB,OurName,5),
+    send_name(SocketB,OurName, ?EPMD_DIST_HIGH),
     alive = recv_status(SocketB),
     send_status(SocketB, true),
     gen_tcp:close(SocketA),
-    {hidden,Node,5,HisChallengeB} = recv_challenge(SocketB), % See 1)
+    {hidden,Node,?EPMD_DIST_HIGH,HisChallengeB} = recv_challenge(SocketB), % See 1)
     OurChallengeB = gen_challenge(),
     OurDigestB = gen_digest(HisChallengeB, Cookie),
     send_challenge_reply(SocketB, OurChallengeB, OurDigestB),
@@ -254,7 +260,7 @@ simultaneous_md5(Node, OurName, Cookie) when OurName < Node ->
 		  Else ->
 		      exit(Else)
 	      end,
-    EpmdSocket = register(OurName, LSocket, 1, 5),
+    EpmdSocket = register_node(OurName, LSocket, ?EPMD_DIST_LOW, ?EPMD_DIST_HIGH),
     {NA, NB} = split(Node),
     rpc:cast(Node, net_adm, ping, [OurName]),
     receive after 1000 -> ok end,
@@ -262,7 +268,7 @@ simultaneous_md5(Node, OurName, Cookie) when OurName < Node ->
     {ok, SocketA} = gen_tcp:connect(atom_to_list(NB),PortNo,
 				    [{active,false},
 				     {packet,2}]),
-    send_name(SocketA,OurName,5),
+    send_name(SocketA,OurName, ?EPMD_DIST_HIGH),
     %% We are still not marked up on the other side, as our first message 
     %% is not sent.
     SocketB = case gen_tcp:accept(LSocket) of
@@ -275,11 +281,11 @@ simultaneous_md5(Node, OurName, Cookie) when OurName < Node ->
     %% Now we are expected to close A
     gen_tcp:close(SocketA),
     %% But still Socket B will continue
-    {normal,Node,5} = recv_name(SocketB),  % See 1)
+    {normal,Node,?EPMD_DIST_HIGH} = recv_name(SocketB),  % See 1)
     send_status(SocketB, ok_simultaneous),
     MyChallengeB = gen_challenge(),
-    send_challenge(SocketB, OurName, MyChallengeB,5),
-    HisChallengeB = recv_challenge_reply(SocketB, MyChallengeB, Cookie),
+    send_challenge(SocketB, OurName, MyChallengeB, ?EPMD_DIST_HIGH),
+    {ok,HisChallengeB} = recv_challenge_reply(SocketB, MyChallengeB, Cookie),
     DigestB = gen_digest(HisChallengeB,Cookie),
     send_challenge_ack(SocketB, DigestB),
     inet:setopts(SocketB, [{active, false},
@@ -301,7 +307,8 @@ simultaneous_md5(Node, OurName, Cookie) when OurName > Node ->
 		  Else ->
 		      exit(Else)
 	      end,
-    EpmdSocket = register(OurName, LSocket, 1, 5),
+    EpmdSocket = register_node(OurName, LSocket,
+                               ?EPMD_DIST_LOW, ?EPMD_DIST_HIGH),
     {NA, NB} = split(Node),
     rpc:cast(Node, net_adm, ping, [OurName]),
     receive after 1000 -> ok end,
@@ -315,16 +322,16 @@ simultaneous_md5(Node, OurName, Cookie) when OurName > Node ->
 		  Else2 ->
 		      exit(Else2)
 	      end,
-    send_name(SocketA,OurName,5),
+    send_name(SocketA,OurName, ?EPMD_DIST_HIGH),
     ok_simultaneous = recv_status(SocketA),
     %% Socket B should die during this
     case catch begin
-		   {normal,Node,5} = recv_name(SocketB),  % See 1)
+		   {normal,Node,?EPMD_DIST_HIGH} = recv_name(SocketB),  % See 1)
 		   send_status(SocketB, ok_simultaneous),
 		   MyChallengeB = gen_challenge(),
 		   send_challenge(SocketB, OurName, MyChallengeB,
 				  5),
-		   HisChallengeB = recv_challenge_reply(
+		   {ok,HisChallengeB} = recv_challenge_reply(
 				     SocketB,
 				     MyChallengeB,
 				     Cookie),
@@ -346,7 +353,7 @@ simultaneous_md5(Node, OurName, Cookie) when OurName > Node ->
     end,
     gen_tcp:close(SocketB),
     %% But still Socket A will continue
-    {hidden,Node,5,HisChallengeA} = recv_challenge(SocketA), % See 1)
+    {hidden,Node,?EPMD_DIST_HIGH,HisChallengeA} = recv_challenge(SocketA), % See 1)
     OurChallengeA = gen_challenge(),
     OurDigestA = gen_digest(HisChallengeA, Cookie),
     send_challenge_reply(SocketA, OurChallengeA, OurDigestA),
@@ -372,7 +379,7 @@ missing_compulsory_dflags(Config) when is_list(Config) ->
 				    [{active,false},
 				     {packet,2}]),
     BadNode = list_to_atom(atom_to_list(Name2)++"@"++atom_to_list(NB)),
-    send_name(SocketA,BadNode,5,0),
+    send_name(SocketA,BadNode, ?EPMD_DIST_HIGH, 0),
     not_allowed = recv_status(SocketA),
     gen_tcp:close(SocketA),
     stop_node(Node),
@@ -516,16 +523,16 @@ send_challenge_reply(Socket, Challenge, Digest) ->
 
 recv_challenge_reply(Socket, ChallengeA, Cookie) ->
     case gen_tcp:recv(Socket, 0) of
-	{ok,[$r,CB3,CB2,CB1,CB0 | SumB]} when length(SumB) == 16 ->
+	{ok,[$r,CB3,CB2,CB1,CB0 | SumB]=Data} when length(SumB) == 16 ->
 	    SumA = gen_digest(ChallengeA, Cookie),
 	    ChallengeB = ?u32(CB3,CB2,CB1,CB0),
 	    if SumB == SumA ->
-		    ChallengeB;
+		    {ok,ChallengeB};
 	       true ->
-		    ?shutdown(bad_challenge_reply)
+		    {error,Data}
 	    end;
-	_ ->
-	    ?shutdown(no_node)
+	Err ->
+            {error,Err}
     end.
 
 send_challenge_ack(Socket, Digest) ->
@@ -620,6 +627,13 @@ wait_for_reg_reply(Socket, SoFar) ->
     receive
 	{tcp, Socket, Data0} ->
 	    case SoFar ++ Data0 of
+		[$v, Result, A, B, C, D] ->
+		    case Result of
+			0 ->
+			    {alive, Socket, ?u32(A, B, C, D)};
+			_ ->
+			    {error, duplicate_name}
+		    end;
 		[$y, Result, A, B] ->
 		    case Result of
 			0 ->
@@ -640,7 +654,7 @@ wait_for_reg_reply(Socket, SoFar) ->
     end.
 
 
-register(NodeName, ListenSocket, VLow, VHigh) ->
+register_node(NodeName, ListenSocket, VLow, VHigh) ->
     {ok,{_,TcpPort}} = inet:sockname(ListenSocket),
     case do_register_node(NodeName, TcpPort, VLow, VHigh) of
 	{alive, Socket, _Creation} ->