Merge tag 'OTP-19.0' into sverker/19/binary_to_atom-utf8-crash/ERL-474/OTP-14590

25 files changed, 3978 insertions, 463 deletions

diff --git a/lib/diameter/doc/src/Makefile b/lib/diameter/doc/src/Makefile
index bd2b6b103a..7a7546fc4d 100644
--- a/lib/diameter/doc/src/Makefile
+++ b/lib/diameter/doc/src/Makefile
@@ -1,18 +1,19 @@
 #
 # %CopyrightBegin%
 #
-# Copyright Ericsson AB 2010-2013. All Rights Reserved.
+# Copyright Ericsson AB 2010-2016. All Rights Reserved.
 #
-# The contents of this file are subject to the Erlang Public License,
-# Version 1.1, (the "License"); you may not use this file except in
-# compliance with the License. You should have received a copy of the
-# Erlang Public License along with this software. If not, it can be
-# retrieved online at http://www.erlang.org/.
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
 #
-# Software distributed under the License is distributed on an "AS IS"
-# basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-# the License for the specific language governing rights and limitations
-# under the License.
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
 #
 # %CopyrightEnd%
 
@@ -82,6 +83,7 @@ gifs: $(GIF_FILES:%=$(HTMLDIR)/%)
 man: $(MAN1_FILES) $(MAN3_FILES) $(MAN4_FILES)
 
 $(INDEX_TARGET): $(INDEX_SRC) $(APP_FILE)
+	$(gen_verbose) \
 	sed -e 's/%VSN%/$(VSN)/; \
 	        s/%ERLANG_SITE%/www\.erlang\.se\//; \
 	        s/%UP_ONE_LEVEL%/..\/..\/..\/doc\/index.html/; \
@@ -140,7 +142,10 @@ release_spec:
 
 depend.mk: depend.sed Makefile seealso.ent \
            $(XML_REF_FILES) $(XML_CHAPTER_FILES)
+	$(gen_verbose)
+	$(V_at) \
 	sed -f seehere.sed seealso.ent > seehere.ent
+	$(V_at) \
 	(for f in $(XML_REF_FILES) $(XML_CHAPTER_FILES); do \
 	     sed -f $< $$f | sed "s@%FILE%@`basename $$f .xml`@g"; \
 	 done) \
diff --git a/lib/diameter/doc/src/book.xml b/lib/diameter/doc/src/book.xml
index 960296528b..b6cbcbc560 100644
--- a/lib/diameter/doc/src/book.xml
+++ b/lib/diameter/doc/src/book.xml
@@ -1,24 +1,25 @@
-<?xml version="1.0" encoding="latin1" ?>
+<?xml version="1.0" encoding="utf-8" ?>
 <!DOCTYPE book SYSTEM "book.dtd">
 
 <book xmlns:xi="http://www.w3.org/2001/XInclude">
 
 <header titlestyle="normal">
 <copyright>
-<year>2011</year>
+<year>2011</year><year>2016</year>
 <holder>Ericsson AB. All Rights Reserved.</holder>
 </copyright>
 <legalnotice>
-The contents of this file are subject to the Erlang Public License,
-Version 1.1, (the "License"); you may not use this file except in
-compliance with the License. You should have received a copy of the
-Erlang Public License along with this software. If not, it can be
-retrieved online at http://www.erlang.org/.
-
-Software distributed under the License is distributed on an "AS IS"
-basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-the License for the specific language governing rights and limitations
-under the License.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+ 
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
 
 </legalnotice>
 
diff --git a/lib/diameter/doc/src/depend.sed b/lib/diameter/doc/src/depend.sed
index 42de597f15..9c0a417be2 100644
--- a/lib/diameter/doc/src/depend.sed
+++ b/lib/diameter/doc/src/depend.sed
@@ -1,18 +1,19 @@
 #
 # %CopyrightBegin%
 #
-# Copyright Ericsson AB 2011. All Rights Reserved.
-#
-# The contents of this file are subject to the Erlang Public License,
-# Version 1.1, (the "License"); you may not use this file except in
-# compliance with the License. You should have received a copy of the
-# Erlang Public License along with this software. If not, it can be
-# retrieved online at http://www.erlang.org/.
-#
-# Software distributed under the License is distributed on an "AS IS"
-# basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-# the License for the specific language governing rights and limitations
-# under the License.
+# Copyright Ericsson AB 2011-2016. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
 #
 # %CopyrightEnd%
 
diff --git a/lib/diameter/doc/src/diameter.xml b/lib/diameter/doc/src/diameter.xml
index db19fbb271..d68a78ed6d 100644
--- a/lib/diameter/doc/src/diameter.xml
+++ b/lib/diameter/doc/src/diameter.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="latin1" ?>
+<?xml version="1.0" encoding="utf-8" ?>
 <!DOCTYPE erlref SYSTEM "erlref.dtd" [
   <!ENTITY spawn_opt
   '<seealso marker="erts:erlang#spawn_opt-2">erlang:spawn_opt/2</seealso>'>
@@ -20,20 +20,22 @@
 <header>
 
 <copyright>
-<year>2011</year><year>2013</year>
+<year>2011</year>
+<year>2016</year>
 <holder>Ericsson AB. All Rights Reserved.</holder>
 </copyright>
 <legalnotice>
-The contents of this file are subject to the Erlang Public License,
-Version 1.1, (the "License"); you may not use this file except in
-compliance with the License. You should have received a copy of the
-Erlang Public License along with this software. If not, it can be
-retrieved online at http://www.erlang.org/.
-
-Software distributed under the License is distributed on an "AS IS"
-basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-the License for the specific language governing rights and limitations
-under the License.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+ 
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
 
 </legalnotice>
 
@@ -110,7 +112,7 @@ Defined in &dict_data_types;.</p>
 <tag><c>application_alias() = term()</c></tag>
 <item>
 <p>
-A name identifying a Diameter application in
+Name identifying a Diameter application in
 service configuration.
 Passed to &call; when sending requests
 defined by the application.</p>
@@ -128,9 +130,9 @@ ExtraArgs = list()
 </pre>
 
 <p>
-A module implementing the callback interface defined in &man_app;,
+Module implementing the callback interface defined in &man_app;,
 along with any
-extra arguments to be appended to those documented for the interface.
+extra arguments to be appended to those documented.
 Note that extra arguments specific to an outgoing request can be
 specified to &call;, in which case
 those are are appended to any module-specific extra arguments.</p>
@@ -138,7 +140,7 @@ those are are appended to any module-specific extra arguments.</p>
 <p>
 Specifying a <c>#diameter_callback{}</c> record allows individual
 functions to be configured in place of the usual &man_app; callbacks.
-See that module for details.</p>
+See <c>diameter_callback.erl</c> for details.</p>
 
 <marker id="application_opt"/>
 </item>
@@ -155,7 +157,7 @@ Has one the following types.</p>
 <tag><c>{alias, &application_alias;}</c></tag>
 <item>
 <p>
-An unique identifier for the application in the scope of the
+Unique identifier for the application in the scope of the
 service.
 Defaults to the value of the <c>dictionary</c> option if
 unspecified.</p>
@@ -164,16 +166,16 @@ unspecified.</p>
 <tag><c>{dictionary, atom()}</c></tag>
 <item>
 <p>
-The name of an encode/decode module for the Diameter
+Name of an encode/decode module for the Diameter
 messages defined by the application.
-These modules are generated from a specification file whose format is
-documented in &man_dict;.</p>
+These modules are generated from files whose format is documented in
+&man_dict;.</p>
 </item>
 
 <tag><c>{module, &application_module;}</c></tag>
 <item>
 <p>
-The callback module with which messages of the Diameter application are
+Callback module in which messages of the Diameter application are
 handled.
 See &man_app; for the required interface and semantics.</p>
 </item>
@@ -181,7 +183,7 @@ See &man_app; for the required interface and semantics.</p>
 <tag><c>{state, term()}</c></tag>
 <item>
 <p>
-The initial callback state.
+Initial callback state.
 The prevailing state is passed to some
 &man_app;
 callbacks, which can then return a new state.
@@ -191,25 +193,24 @@ Defaults to the value of the <c>alias</c> option if unspecified.</p>
 <tag><c>{call_mutates_state, true|false}</c></tag>
 <item>
 <p>
-Specifies whether or not the &app_pick_peer;
+Whether or not the &app_pick_peer;
 application callback can modify the application state.
 Defaults to <c>false</c> if unspecified.</p>
 
-<note>
+<warning>
 <p>
-&app_pick_peer; callbacks
-are serialized when these are allowed to modify state, which is a
-potential performance bottleneck.
+&app_pick_peer; callbacks are serialized when this option is <c>true</c>,
+which is a potential performance bottleneck.
 A simple Diameter client may suffer no ill effects from using mutable
 state but a server or agent that responds to incoming request should
 probably avoid it.</p>
-</note>
+</warning>
 </item>
 
 <tag><c>{answer_errors, callback|report|discard}</c></tag>
 <item>
 <p>
-Determines the manner in which incoming answer messages containing
+Manner in which incoming answer messages containing
 decode errors are handled.</p>
 
 <p>
@@ -227,14 +228,14 @@ question is as if a callback had taken place and returned
 <c>{error, failure}</c>.</p>
 
 <p>
-Defaults to <c>report</c> if unspecified.</p>
+Defaults to <c>discard</c> if unspecified.</p>
 </item>
 
 <tag><c>{request_errors, answer_3xxx|answer|callback}</c></tag>
 <item>
 <p>
-Determines the manner in which incoming requests are handled when an
-error other than 3007, DIAMETER_APPLICATION_UNSUPPORTED (which cannot
+Manner in which incoming requests are handled when an
+error other than 3007 (DIAMETER_APPLICATION_UNSUPPORTED, which cannot
 be associated with an application callback module), is detected.</p>
 
 <p>
@@ -244,7 +245,8 @@ If <c>answer</c> then even 5xxx errors are answered without a
 callback unless the connection in question has configured the RFC 3588
 common dictionary as noted below.
 If <c>callback</c> then a &app_handle_request; callback always takes
-place and the return value determines the answer sent to the peer.</p>
+place and its return value determines the answer sent to the peer, if
+any.</p>
 
 <p>
 Defaults to <c>answer_3xxx</c> if unspecified.</p>
@@ -252,13 +254,14 @@ Defaults to <c>answer_3xxx</c> if unspecified.</p>
 <note>
 <p>
 Answers sent by diameter set the E-bit in the Diameter Header.
-Since RFC 3588 allowed only 3xxx result codes in an
+Since RFC 3588 allows only 3xxx result codes in an
 <c>answer-message</c>, <c>answer</c> has the same semantics as
-<c>answer_3xxx</c> if the peer connection in question has configured
-the RFC 3588 common dictionary, <c>diameter_gen_base_rfc3588</c>.
-RFC 6733 allows both 3xxx and 5xxx result codes in an
-<c>answer-message</c> so a connection configured with the RFC 6733
-common dictionary, <c>diameter_gen_base_rfc6733</c>, does
+<c>answer_3xxx</c> when the transport in question has
+been configured with <c>diameter_gen_base_rfc3588</c> as its common
+dictionary.
+Since RFC 6733 allows both 3xxx and 5xxx result codes in an
+<c>answer-message</c>, a transport with
+<c>diameter_gen_base_rfc6733</c> as its common dictionary does
 distinguish between <c>answer_3xxx</c> and <c>answer</c>.</p>
 </note>
 </item>
@@ -291,9 +294,8 @@ Multiple options append to the argument list.</p>
 <tag><c>{filter, &peer_filter;}</c></tag>
 <item>
 <p>
-A filter to apply to the list of available peers before passing them to
-the &app_pick_peer;
-callback for the application in question.
+Filter to apply to the list of available peers before passing it to
+the &app_pick_peer; callback for the application in question.
 Multiple options are equivalent a single <c>all</c> filter on the
 corresponding list of filters.
 Defaults to <c>none</c>.</p>
@@ -302,7 +304,7 @@ Defaults to <c>none</c>.</p>
 <tag><c>{timeout, &dict_Unsigned32;}</c></tag>
 <item>
 <p>
-The number of milliseconds after which the request should
+Number of milliseconds after which the request should
 timeout.
 Defaults to 5000.</p>
 </item>
@@ -310,9 +312,9 @@ Defaults to 5000.</p>
 <tag><c>detach</c></tag>
 <item>
 <p>
-Causes &call; to return <c>ok</c> as
+Cause &call; to return <c>ok</c> as
 soon as the request in
-question has been encoded instead of waiting for and returning
+question has been encoded, instead of waiting for and returning
 the result from a subsequent &app_handle_answer; or
 &app_handle_error; callback.</p>
 </item>
@@ -331,8 +333,8 @@ An invalid option will cause &call; to fail.</p>
 <p>
 AVP values sent in outgoing CER or CEA messages during capabilities
 exchange.
-Can be configured both on a service and a transport, values specified
-on the latter taking precedence over any specified on the former.
+Can be configured both on a service and a transport, values
+on the latter taking precedence.
 Has one of the following types.</p>
 
 <taglist>
@@ -355,10 +357,10 @@ question communicates an address list as described in
 <tag><c>{'Origin-State-Id', &dict_Unsigned32;}</c></tag>
 <item>
 <p>
-Origin-State-Id is optional but will be included in outgoing messages
-sent by diameter itself: CER/CEA, DWR/DWA and DPR/DPA.
+Origin-State-Id is optional but, if configured, will be included in
+outgoing CER/CEA and DWR/DWA messages.
 Setting a value of <c>0</c> (zero) is equivalent to not setting a
-value as documented in &the_rfc;.
+value, as documented in &the_rfc;.
 The function &origin_state_id;
 can be used as to retrieve a value that is computed when the diameter
 application is started.</p>
@@ -370,8 +372,8 @@ application is started.</p>
 <item>
 <p>
 Inband-Security-Id defaults to the empty list, which is equivalent to a
-list containing only 0 (= NO_INBAND_SECURITY).
-If 1 (= TLS) is specified then TLS is selected if the CER/CEA received
+list containing only 0 (NO_INBAND_SECURITY).
+If 1 (TLS) is specified then TLS is selected if the CER/CEA received
 from the peer offers it.</p>
 </item>
 
@@ -426,7 +428,7 @@ configuration passed to &start_service; or &add_transport;.</p>
 <tag><c>peer_filter() = term()</c></tag>
 <item>
 <p>
-A filter passed to &call; in order to select candidate peers for a
+Filter passed to &call; in order to select candidate peers for a
 &app_pick_peer; callback.
 Has one of the following types.</p>
 
@@ -437,38 +439,38 @@ Has one of the following types.</p>
 <p>
 Matches any peer.
 This is a convenience that provides a filter equivalent to no
-filter at all.</p>
+filter.</p>
 </item>
 
 <tag><c>host</c></tag>
 <item>
 <p>
-Matches only those peers whose <c>Origin-Host</c> has the same value
-as <c>Destination-Host</c> in the outgoing request in question,
+Matches only those peers whose Origin-Host has the same value
+as Destination-Host in the outgoing request in question,
 or any peer if the request does not contain
-a <c>Destination-Host</c> AVP.</p>
+a Destination-Host AVP.</p>
 </item>
 
 <tag><c>realm</c></tag>
 <item>
 <p>
-Matches only those peers whose <c>Origin-Realm</c> has the same value
-as <c>Destination-Realm</c> in the outgoing request in question,
+Matches only those peers whose Origin-Realm has the same value
+as Destination-Realm in the outgoing request in question,
 or any peer if the request does not contain
-a <c>Destination-Realm</c> AVP.</p>
+a Destination-Realm AVP.</p>
 </item>
 
 <tag><c>{host, any|&dict_DiameterIdentity;}</c></tag>
 <item>
 <p>
-Matches only those peers whose <c>Origin-Host</c> has the
+Matches only those peers whose Origin-Host has the
 specified value, or all peers if the atom <c>any</c>.</p>
 </item>
 
-<tag><c>{realm, any|&dict_DiameterIdentity;</c></tag>
+<tag><c>{realm, any|&dict_DiameterIdentity;}</c></tag>
 <item>
 <p>
-Matches only those peers whose <c>Origin-Realm</c> has the
+Matches only those peers whose Origin-Realm has the
 specified value, or all peers if the atom <c>any</c>.</p>
 </item>
 
@@ -477,7 +479,8 @@ specified value, or all peers if the atom <c>any</c>.</p>
 <p>
 Matches only those peers for which the specified
 <c>&evaluable;</c> returns
-<c>true</c> on the connection's <c>diameter_caps</c> record.
+<c>true</c> when applied to the connection's <c>diameter_caps</c>
+record.
 Any other return value or exception is equivalent to <c>false</c>.</p>
 </item>
 
@@ -497,7 +500,23 @@ Matches only those peers matched by each filter in the specified list.</p>
 <item>
 <p>
 Matches only those peers matched by at least one filter in the
-specified list.</p>
+specified list.
+The resulting list will be in match order, peers matching the
+first filter of the list sorting before those matched by the second,
+and so on.</p>
+</item>
+
+<tag><c>{first, [&peer_filter;]}</c></tag>
+<item>
+<p>
+Like <c>any</c>, but stops at the first filter for which there are
+matches, which can be much more efficient when there are many peers.
+For example, the following filter causes only peers best matching
+both the host and realm filters to be presented.</p>
+
+<pre>
+{first, [{all, [host, realm]}, realm]}
+</pre>
 </item>
 
 </taglist>
@@ -508,10 +527,10 @@ that matches no peer.</p>
 
 <note>
 <p>
-The <c>host</c> and <c>realm</c> filters examine the
-outgoing request as passed to &call;,
-assuming that this is a record- or list-valued <c>&codec_message;</c>,
-and that the message contains at most one of each AVP.
+The <c>host</c> and <c>realm</c> filters cause the Destination-Host
+and Destination-Realm AVPs to be extracted from the
+outgoing request, assuming it to be a record- or list-valued
+<c>&codec_message;</c>, and assuming at most one of each AVP.
 If this is not the case then the <c>{host|realm, &dict_DiameterIdentity;}</c>
 filters must be used to achieve the desired result.
 An empty <c>&dict_DiameterIdentity;</c>
@@ -555,7 +574,7 @@ Can have one of the following types.</p>
 <p>
 The service is being started or stopped.
 No event precedes a <c>start</c> event.
-No event follows a <c>stop</c> event and this event
+No event follows a <c>stop</c> event, and this event
 implies the termination of all transport processes.</p>
 </item>
 
@@ -575,16 +594,15 @@ The RFC 3539 watchdog state machine has
 transitioned into (<c>up</c>) or out of (<c>down</c>) the OKAY
 state.
 If a <c>#diameter_packet{}</c> is present in an <c>up</c> event
-then there has been a capabilties exchange on a newly established
-transport connection and the record contains the received CER or CEA.
-Otherwise a connection has reestablished without the loss or
-connectivity.</p>
+then there has been a capabilities exchange on a newly established
+transport connection and the record contains the received CER or
+CEA.</p>
 
 <p>
 Note that a single <c>up</c> or <c>down</c> event for a given peer
 corresponds to multiple &app_peer_up; or &app_peer_down;
 callbacks, one for each of the Diameter applications negotiated during
-capablilities exchange.
+capabilities exchange.
 That is, the event communicates connectivity with the
 peer as a whole while the callbacks communicate connectivity with
 respect to individual Diameter applications.</p>
@@ -599,7 +617,7 @@ Opts = [&transport_opt;]
 
 <p>
 A connecting transport is attempting to establish/reestablish a
-transport connection with a peer following &reconnect_timer; or
+transport connection with a peer following &connect_timer; or
 &watchdog_timer; expiry.</p>
 </item>
 
@@ -627,10 +645,10 @@ CB = &evaluable;
 </pre>
 
 <p>
-An incoming CER has been answered with the indicated result code or
+An incoming CER has been answered with the indicated result code, or
 discarded.
-<c>Caps</c> contains pairs of values for the local node and remote
-peer.
+<c>Caps</c> contains pairs of values, for the local node and remote
+peer respectively.
 <c>Pkt</c> contains the CER in question.
 In the case of rejection by a capabilities callback, the tuple
 contains the rejecting callback.</p>
@@ -647,7 +665,7 @@ Pkt  = #diameter_packet{}
 <p>
 An incoming CER contained errors and has been answered with the
 indicated result code.
-<c>Caps</c> contains only values for the local node.
+<c>Caps</c> contains values for the local node only.
 <c>Pkt</c> contains the CER in question.</p>
 </item>
 
@@ -661,7 +679,7 @@ connection establishment.</p>
 <tag><c>{'CEA', Result, Caps, Pkt}</c></tag>
 <item>
 <pre>
-Result = integer() | atom() | {capabilities_cb, CB, ResultCode|discard}
+Result = ResultCode | atom() | {capabilities_cb, CB, ResultCode|discard}
 Caps = #diameter_caps{}
 Pkt  = #diameter_packet{}
 ResultCode = integer()
@@ -729,7 +747,7 @@ info fields of forms other than the above.</p>
 <tag><c>service_name() = term()</c></tag>
 <item>
 <p>
-The name of a service as passed to &start_service; and with which the
+Name of a service as passed to &start_service; and with which the
 service is identified.
 There can be at most one service with a given name on a given node.
 Note that &make_ref;
@@ -741,7 +759,7 @@ can be used to generate a service name that is somewhat unique.</p>
 <tag><c>service_opt()</c></tag>
 <item>
 <p>
-An option passed to &start_service;.
+Option passed to &start_service;.
 Can be any <c>&capability;</c> as well as the following.</p>
 
 <taglist>
@@ -749,12 +767,12 @@ Can be any <c>&capability;</c> as well as the following.</p>
 <tag><c>{application, [&application_opt;]}</c></tag>
 <item>
 <p>
-Defines a Diameter application supported by the service.</p>
+A Diameter application supported by the service.</p>
 
 <p>
 A service must configure one tuple for each Diameter
 application it intends to support.
-For an outgoing Diameter request, the relevant <c>&application_alias;</c> is
+For an outgoing request, the relevant <c>&application_alias;</c> is
 passed to &call;, while for an
 incoming request the application identifier in the message
 header determines the application, the identifier being specified in
@@ -765,11 +783,24 @@ the application's &dictionary; file.</p>
 The capabilities advertised by a node must match its configured
 applications. In particular, <c>application</c> configuration must
 be matched by corresponding &capability; configuration, of
-Application-Id AVP's in particular.</p>
+*-Application-Id AVPs in particular.</p>
 </warning>
 
 </item>
 
+<marker id="incoming_maxlen"/>
+<tag><c>{incoming_maxlen, 0..16777215}</c></tag>
+<item>
+<p>
+Bound on the expected size of incoming Diameter messages.
+Messages larger than the specified number of bytes are discarded.</p>
+
+<p>
+Defaults to <c>16777215</c>, the maximum value of the 24-bit Message
+Length field in a Diameter Header.</p>
+
+</item>
+
 <tag><c>{restrict_connections, false
                              | node
                              | nodes
@@ -777,11 +808,12 @@ Application-Id AVP's in particular.</p>
                              | evaluable()}</c></tag>
 <item>
 <p>
-Specifies the degree to which the service allows multiple transport
-connections to the same peer.</p>
+The degree to which the service allows multiple transport
+connections to the same peer, as identified by its Origin-Host
+at capabilities exchange.</p>
 
 <p>
-If type <c>[node()]</c> then a connection is rejected if another already
+If <c>[node()]</c> then a connection is rejected if another already
 exists on any of the specified nodes.
 Types <c>false</c>, <c>node</c>, <c>nodes</c> and
 &evaluable; are equivalent to
@@ -802,9 +834,9 @@ Defaults to <c>nodes</c>.</p>
 <tag><c>{sequence, {H,N} | &evaluable;}</c></tag>
 <item>
 <p>
-Specifies a constant value <c>H</c> for the topmost <c>32-N</c> bits of
-of 32-bit End-to-End and Hop-by-Hop identifiers generated
-by the service, either explicity or as a return value of a function
+A constant value <c>H</c> for the topmost <c>32-N</c> bits of
+of 32-bit End-to-End and Hop-by-Hop Identifiers generated
+by the service, either explicitly or as a return value of a function
 to be evaluated at &start_service;.
 In particular, an identifier <c>Id</c> is mapped to a new identifier
 as follows.</p>
@@ -812,11 +844,11 @@ as follows.</p>
 (H bsl N) bor (Id band ((1 bsl N) - 1))
 </pre>
 <p>
-Note that &the_rfc; requires that End-to-End identifiers remain unique
+Note that &the_rfc; requires that End-to-End Identifiers remain unique
 for a period of at least 4 minutes and that this and the call rate
-places a lower bound on the appropriate values of <c>N</c>:
-at a rate of <c>R</c> requests per second an <c>N</c>-bit counter
-traverses all of its values in <c>(1 bsl N) div (R*60)</c> minutes so
+places a lower bound on appropriate values of <c>N</c>:
+at a rate of <c>R</c> requests per second, an <c>N</c>-bit counter
+traverses all of its values in <c>(1 bsl N) div (R*60)</c> minutes, so
 the bound is <c>4*R*60 =&lt; 1 bsl N</c>.</p>
 
 <p><c>N</c> must lie in the range <c>0..32</c> and <c>H</c> must be a
@@ -829,7 +861,7 @@ Defaults to <c>{0,32}</c>.</p>
 <p>
 Multiple Erlang nodes implementing the same Diameter node should
 be configured with different sequence masks to ensure that each node
-uses a unique range of End-to-End and Hop-by-Hop identifiers for
+uses a unique range of End-to-End and Hop-by-Hop Identifiers for
 outgoing requests.</p>
 </warning>
 </item>
@@ -837,7 +869,7 @@ outgoing requests.</p>
 <tag><c>{share_peers, boolean() | [node()] | evaluable()}</c></tag>
 <item>
 <p>
-Specifies nodes to which peer connections established on the local
+Nodes to which peer connections established on the local
 Erlang node are communicated.
 Shared peers become available in the remote candidates list passed to
 &app_pick_peer; callbacks on remote nodes whose services are
@@ -852,7 +884,7 @@ by the specified function, evaluated whenever a peer connection
 becomes available or a remote service requests information about local
 connections.
 The value <c>true</c> is equivalent to <c>fun &nodes;</c>.
-The value <c>node()</c> in a node list is ignored, so a collection of
+The value <c>node()</c> in a list is ignored, so a collection of
 services can all be configured to share with the same list of
 nodes.</p>
 
@@ -876,7 +908,7 @@ of a single Diameter node across multiple Erlang nodes.</p>
 <tag><c>{spawn_opt, [term()]}</c></tag>
 <item>
 <p>
-An options list passed to &spawn_opt; when spawning a process for an
+Options list passed to &spawn_opt; when spawning a process for an
 incoming Diameter request, unless the transport in question
 specifies another value.
 Options <c>monitor</c> and <c>link</c> are ignored.</p>
@@ -885,10 +917,77 @@ Options <c>monitor</c> and <c>link</c> are ignored.</p>
 Defaults to the empty list.</p>
 </item>
 
+<marker id="strict_mbit"/>
+<tag><c>{strict_mbit, boolean()}</c></tag>
+<item>
+<p>
+Whether or not to regard an AVP setting the M-bit as erroneous when
+the command grammar in question does not explicitly allow the AVP.
+If <c>true</c> then such AVPs are regarded as 5001 errors,
+DIAMETER_AVP_UNSUPPORTED.
+If <c>false</c> then the M-bit is ignored and policing
+it becomes the receiver's responsibility.</p>
+
+<p>
+Defaults to <c>true</c>.</p>
+
+<warning>
+<p>
+RFC 6733 is unclear about the semantics of the M-bit.
+One the one hand, the CCF specification in section 3.2 documents AVP
+in a command grammar as meaning <b>any</b> arbitrary AVP; on the
+other hand, 1.3.4 states that AVPs setting the M-bit cannot be added
+to an existing command: the modified command must instead be
+placed in a new Diameter application.</p>
+<p>
+The reason for the latter is presumably interoperability:
+allowing arbitrary AVPs setting the M-bit in a command makes its
+interpretation implementation-dependent, since there's no
+guarantee that all implementations will understand the same set of
+arbitrary AVPs in the context of a given command.
+However, interpreting <c>AVP</c> in a command grammar as <b>any</b>
+AVP, regardless of M-bit, renders 1.3.4 meaningless, since the receiver
+can simply ignore any AVP it thinks isn't relevant, regardless of the
+sender's intent.</p>
+<p>
+Beware of confusing mandatory in the sense of the M-bit with mandatory
+in the sense of the command grammar.
+The former is a semantic requirement: that the receiver understand the
+semantics of the AVP in the context in question.
+The latter is a syntactic requirement: whether or not the AVP must
+occur in the message in question.</p>
+</warning>
+
+</item>
+
+<marker id="string_decode"/>
+<tag><c>{string_decode, boolean()}</c></tag>
+<item>
+<p>
+Whether or not to decode AVPs of type &dict_OctetString; and its
+derived types &dict_DiameterIdentity;, &dict_DiameterURI;,
+&dict_IPFilterRule;, &dict_QoSFilterRule;, and &dict_UTF8String;.
+If <c>true</c> then AVPs of these types are decoded to string().
+If <c>false</c> then values are retained as binary().</p>
+
+<p>
+Defaults to <c>true</c>.</p>
+
+<warning>
+<p>
+This option should be set to <c>false</c>
+since a sufficiently malicious peer can otherwise cause large amounts
+of memory to be consumed when decoded Diameter messages are passed
+between processes.
+The default value is for backwards compatibility.</p>
+</warning>
+
+</item>
+
 <tag><c>{use_shared_peers, boolean() | [node()] | evaluable()}</c></tag>
 <item>
 <p>
-Specifies nodes from which communicated peers are made available in
+Nodes from which communicated peers are made available in
 the remote candidates list of &app_pick_peer; callbacks.</p>
 
 <p>
@@ -899,7 +998,7 @@ If <c>evaluable()</c> then only peers returned by the specified
 function are used, evaluated whenever a remote service communicates
 information about an available peer connection.
 The value <c>true</c> is equivalent to <c>fun &nodes;</c>.
-The value <c>node()</c> in a node list is ignored.</p>
+The value <c>node()</c> in a list is ignored.</p>
 
 <p>
 Defaults to <c>false</c>.</p>
@@ -928,7 +1027,7 @@ each node from which requests are sent.</p>
 <tag><c>transport_opt()</c></tag>
 <item>
 <p>
-An option passed to &add_transport;.
+Option passed to &add_transport;.
 Has one of the following types.</p>
 
 <taglist>
@@ -936,8 +1035,7 @@ Has one of the following types.</p>
 <tag><c>{applications, [&application_alias;]}</c></tag>
 <item>
 <p>
-The list of Diameter applications to which the transport should be
-restricted.
+Diameter applications to which the transport should be restricted.
 Defaults to all applications configured on the service in question.
 Applications not configured on the service in question are ignored.</p>
 
@@ -946,7 +1044,7 @@ Applications not configured on the service in question are ignored.</p>
 The capabilities advertised by a node must match its configured
 applications.
 In particular, setting <c>applications</c> on a transport typically
-implies having to set matching Application-Id AVP's in a
+implies having to set matching *-Application-Id AVPs in a
 &capabilities; tuple.</p>
 </warning>
 
@@ -956,7 +1054,7 @@ implies having to set matching Application-Id AVP's in a
 <tag><c>{capabilities, [&capability;]}</c></tag>
 <item>
 <p>
-AVP's used to construct outgoing CER/CEA messages.
+AVPs used to construct outgoing CER/CEA messages.
 Values take precedence over any specified on the service in
 question.</p>
 
@@ -970,7 +1068,7 @@ TLS is desired over TCP as implemented by &man_tcp;.</p>
 <tag><c>{capabilities_cb, &evaluable;}</c></tag>
 <item>
 <p>
-A callback invoked upon reception of CER/CEA during capabilities
+Callback invoked upon reception of CER/CEA during capabilities
 exchange in order to ask whether or not the connection should
 be accepted.
 Applied to the <c>&transport_ref;</c> and
@@ -1018,32 +1116,61 @@ case the corresponding callbacks are applied until either all return
 <tag><c>{capx_timeout, &dict_Unsigned32;}</c></tag>
 <item>
 <p>
-The number of milliseconds after which a transport process having an
+Number of milliseconds after which a transport process having an
 established transport connection will be terminated if the expected
 capabilities exchange message (CER or CEA) is not received from the peer.
-For a connecting transport, the timing of reconnection attempts is
-governed by &watchdog_timer; or &reconnect_timer; expiry.
+For a connecting transport, the timing of connection attempts is
+governed by &connect_timer; or &watchdog_timer; expiry.
 For a listening transport, the peer determines the timing.</p>
 
 <p>
 Defaults to 10000.</p>
 </item>
 
+<marker id="connect_timer"/>
+<tag><c>{connect_timer, Tc}</c></tag>
+<item>
+<pre>
+Tc = &dict_Unsigned32;
+</pre>
+
+<p>
+For a connecting transport, the &the_rfc; Tc timer, in milliseconds.
+This timer determines the frequency with which a transport
+attempts to establish an initial connection with its peer
+following transport configuration.
+Once an initial connection has been
+established, &watchdog_timer; determines the frequency of
+reconnection attempts, as required by RFC 3539.</p>
+
+<p>
+For a listening transport, the timer specifies the time after which a
+previously connected peer will be forgotten: a connection after this time is
+regarded as an initial connection rather than reestablishment,
+causing the RFC 3539 state machine to pass to state OKAY rather than
+REOPEN.
+Note that these semantics are not governed by the RFC and
+that a listening transport's &connect_timer; should be greater
+than its peer's Tw plus jitter.</p>
+
+<p>
+Defaults to 30000 for a connecting transport and 60000 for a listening
+transport.</p>
+</item>
+
 <marker id="disconnect_cb"/>
 <tag><c>{disconnect_cb, &evaluable;}</c></tag>
 
 <item>
 <p>
-A callback invoked prior to terminating the transport process of a
+Callback invoked prior to terminating the transport process of a
 transport connection having watchdog state <c>OKAY</c>.
-Applied to <c>Reason=transport|service|application</c> and the
-<c>&transport_ref;</c> and
-<c>&app_peer;</c>
-in question, <c>Reason</c> indicating whether the diameter
-application is being stopped, the service in question is being stopped
-at &stop_service; or
-the transport in question is being removed at &remove_transport;,
-respectively.</p>
+Applied to <c>application|service|transport</c> and the
+<c>&transport_ref;</c> and <c>&app_peer;</c> in question:
+<c>application</c> indicates that the diameter application is
+being stopped, <c>service</c> that the service in question is being
+stopped by &stop_service;, and <c>transport</c> that the transport in
+question is being removed by &remove_transport;.</p>
 
 <p>
 The return value can have one of the following types.</p>
@@ -1052,7 +1179,7 @@ The return value can have one of the following types.</p>
 <tag><c>{dpr, [option()]}</c></tag>
 <item>
 <p>
-Causes Disconnect-Peer-Request to be sent to the peer, the transport
+Send Disconnect-Peer-Request to the peer, the transport
 process being terminated following reception of
 Disconnect-Peer-Answer or timeout.
 An <c>option()</c> can be one of the following.</p>
@@ -1061,7 +1188,7 @@ An <c>option()</c> can be one of the following.</p>
 <tag><c>{cause, 0|rebooting|1|busy|2|goaway}</c></tag>
 <item>
 <p>
-The Disconnect-Cause to send, <c>REBOOTING</c>, <c>BUSY</c> and
+Disconnect-Cause to send, <c>REBOOTING</c>, <c>BUSY</c> and
 <c>DO_NOT_WANT_TO_TALK_TO_YOU</c> respectively.
 Defaults to <c>rebooting</c> for <c>Reason=service|application</c> and
 <c>goaway</c> for <c>Reason=transport</c>.</p>
@@ -1070,9 +1197,9 @@ Defaults to <c>rebooting</c> for <c>Reason=service|application</c> and
 <tag><c>{timeout, &dict_Unsigned32;}</c></tag>
 <item>
 <p>
-The number of milliseconds after which the transport process is
+Number of milliseconds after which the transport process is
 terminated if DPA has not been received.
-Defaults to 1000.</p>
+Defaults to the value of &dpa_timeout;.</p>
 </item>
 </taglist>
 </item>
@@ -1086,7 +1213,7 @@ Equivalent to <c>{dpr, []}</c>.</p>
 <tag><c>close</c></tag>
 <item>
 <p>
-Causes the transport process to be terminated without
+Terminate the transport process without
 Disconnect-Peer-Request being sent to the peer.</p>
 </item>
 
@@ -1109,11 +1236,34 @@ configured them.</p>
 Defaults to a single callback returning <c>dpr</c>.</p>
 </item>
 
+<marker id="dpa_timeout"/>
+<tag><c>{dpa_timeout, &dict_Unsigned32;}</c></tag>
+<item>
+<p>
+Number of milliseconds after which a transport connection is
+terminated following an outgoing DPR if DPA is not received.</p>
+
+<p>
+Defaults to 1000.</p>
+</item>
+
+<marker id="dpr_timeout"/>
+<tag><c>{dpr_timeout, &dict_Unsigned32;}</c></tag>
+<item>
+<p>
+Number of milliseconds after which a transport connection is
+terminated following an incoming DPR if the peer does not close the
+connection.</p>
+
+<p>
+Defaults to 5000.</p>
+</item>
+
 <marker id="length_errors"/>
 <tag><c>{length_errors, exit|handle|discard}</c></tag>
 <item>
 <p>
-Specifies how to deal with errors in the Message Length field of the
+How to deal with errors in the Message Length field of the
 Diameter Header in an incoming message.
 An error in this context is that the length is not at least 20 bytes
 (the length of a Header), is not a multiple of 4 (a valid length) or
@@ -1121,9 +1271,7 @@ is not the length of the message in question, as received over the
 transport interface documented in &man_transport;.</p>
 
 <p>
-If <c>exit</c> then a warning report is emitted and the parent of the
-transport process in question exits, which causes the transport
-process itself to exit as described in &man_transport;.
+If <c>exit</c> then the transport process in question exits.
 If <c>handle</c> then the message is processed as usual, a resulting
 &app_handle_request; or &app_handle_answer; callback (if one takes
 place) indicating the <c>5015</c> error (DIAMETER_INVALID_MESSAGE_LENGTH).
@@ -1145,41 +1293,26 @@ See &man_tcp; for the behaviour of that module.</p>
 </note>
 </item>
 
-<marker id="reconnect_timer"/>
-<tag><c>{reconnect_timer, Tc}</c></tag>
+<tag><c>{pool_size, pos_integer()}</c></tag>
 <item>
-<pre>
-Tc = &dict_Unsigned32;
-</pre>
-
 <p>
-For a connecting transport, the &the_rfc; Tc timer, in milliseconds.
-Note that this timer determines the frequency with which a transport
-will attempt to establish a connection with its peer only <em>before</em>
-an initial connection is established: once there is an initial
-connection it's &watchdog_timer; that determines the
-frequency of reconnection attempts, as required by RFC 3539.</p>
-
-<p>
-For a listening transport, the timer specifies the time after which a
-previously connected peer will be forgotten: a connection after this time is
-regarded as an initial connection rather than a reestablishment,
-causing the RFC 3539 state machine to pass to state OKAY rather than
-REOPEN.
-Note that these semantics are not governed by the RFC and
-that a listening transport's &reconnect_timer; should be greater
-than its peer's Tw plus jitter.</p>
+Number of transport processes to start.
+For a listening transport, determines the size of the pool of
+accepting transport processes, a larger number being desirable for
+processing multiple concurrent peer connection attempts.
+For a connecting transport, determines the number of connections to
+the peer in question that will be attempted to be establshed:
+the &service_opt;: <c>restrict_connections</c> should also be
+configured on the service in question to allow multiple connections to
+the same peer.</p>
 
-<p>
-Defaults to 30000 for a connecting transport and 60000 for a listening
-transport.</p>
 </item>
 
 <marker id="spawn_opt"/>
 <tag><c>{spawn_opt, [term()]}</c></tag>
 <item>
 <p>
-An options list passed to &spawn_opt; when spawning a process for an
+Options passed to &spawn_opt; when spawning a process for an
 incoming Diameter request.
 Options <c>monitor</c> and <c>link</c> are ignored.</p>
 
@@ -1192,7 +1325,7 @@ Defaults to the list configured on the service if not specified.</p>
 <tag><c>{transport_config, term(), &dict_Unsigned32; | infinity}</c></tag>
 <item>
 <p>
-A term passed as the third argument to the &transport_start; function of
+Term passed as the third argument to the &transport_start; function of
 the relevant &transport_module; in order to
 start a transport process.
 Defaults to the empty list if unspecified.</p>
@@ -1220,7 +1353,7 @@ To listen on both SCTP and TCP, define one transport for each.</p>
 <tag><c>{transport_module, atom()}</c></tag>
 <item>
 <p>
-A module implementing a transport process as defined in &man_transport;.
+Module implementing a transport process as defined in &man_transport;.
 Defaults to <c>diameter_tcp</c> if unspecified.</p>
 
 <p>
@@ -1240,7 +1373,7 @@ corresponding timeout (see below) or all fail.</p>
 <tag><c>{watchdog_config, [{okay|suspect, non_neg_integer()}]}</c></tag>
 <item>
 <p>
-Specifies configuration that alters the behaviour of the watchdog
+Configuration that alters the behaviour of the watchdog
 state machine.
 On key <c>okay</c>, the non-negative number of answered DWR
 messages before transitioning from REOPEN to OKAY.
@@ -1295,7 +1428,7 @@ in predicate functions passed to &remove_transport;.</p>
 <tag><c>transport_ref() = reference()</c></tag>
 <item>
 <p>
-An reference returned by &add_transport; that
+Reference returned by &add_transport; that
 identifies the configuration.</p>
 </item>
 
@@ -1631,11 +1764,13 @@ An example return value with for a client service with Origin-Host
                       {send_pend,0}]}]},
   {statistics,[{{{0,258,0},recv},3},
                {{{0,258,1},send},3},
+               {{{0,258,0},recv,{'Result-Code',2001}},3},
                {{{0,257,0},recv},1},
                {{{0,257,1},send},1},
-               {{{0,258,0},recv,{'Result-Code',2001}},3},
+               {{{0,257,0},recv,{'Result-Code',2001}},1},
                {{{0,280,1},recv},2},
-               {{{0,280,0},send},2}]}]]
+               {{{0,280,0},send},2},
+               {{{0,280,0},send,{'Result-Code',2001}},2}]}]]
 </pre>
 
 <p>
@@ -1661,7 +1796,7 @@ R_Flag}</c>.</p>
 Note that <c>watchdog</c>, <c>peer</c>, <c>apps</c>, <c>caps</c>
 and <c>port</c> entries depend on connectivity
 with the peer and may not be present.
-Note also that the <c>statistics</c> entry presents values acuumulated
+Note also that the <c>statistics</c> entry presents values accumulated
 during the lifetime of the transport configuration.</p>
 
 <p>
@@ -1711,19 +1846,31 @@ connection might look as follows.</p>
            [{watchdog,{&lt;0.72.0>,{1346,171491,998404},initial}}]]},
   {statistics,[{{{0,280,0},recv},7},
                {{{0,280,1},send},7},
-               {{{0,258,0},send,{'Result-Code',2001}},3},
+               {{{0,280,0},recv,{'Result-Code',2001}},7},
                {{{0,258,1},recv},3},
                {{{0,258,0},send},3},
+               {{{0,258,0},send,{'Result-Code',2001}},3},
                {{{0,280,1},recv},5},
                {{{0,280,0},send},5},
+               {{{0,280,0},send,{'Result-Code',2001}},5},
                {{{0,257,1},recv},1},
-               {{{0,257,0},send},1}]}]]
+               {{{0,257,0},send},1},
+               {{{0,257,0},send,{'Result-Code',2001}},1}]}]]
 </pre>
 
 <p>
 The information presented here is as in the <c>connect</c> case except
 that the client connections are grouped under an <c>accept</c> tuple.</p>
 
+<p>
+Whether or not the &transport_opt; <c>pool_size</c> has been
+configured affects the format
+of the listing in the case of a connecting transport, since a value
+greater than 1 implies multiple transport processes for the same
+<c>&transport_ref;</c>, as in the listening case.
+The format in this case is similar to the listening case, with a
+<c>pool</c> tuple in place of an <c>accept</c> tuple.</p>
+
 </item>
 
 <tag><c>connections</c></tag>
@@ -1776,13 +1923,16 @@ A return value for the server above might look as follows.</p>
                       {send_pend,0}]}]},
   {statistics,[{{{0,280,0},recv},62},
                {{{0,280,1},send},62},
-               {{{0,258,0},send,{'Result-Code',2001}},3},
+               {{{0,280,0},recv,{'Result-Code',2001}},62},
                {{{0,258,1},recv},3},
                {{{0,258,0},send},3},
+               {{{0,258,0},send,{'Result-Code',2001}},3},
                {{{0,280,1},recv},66},
                {{{0,280,0},send},66},
+               {{{0,280,0},send,{'Result-Code',2001}},66},
                {{{0,257,1},recv},1},
-               {{{0,257,0},send},1}]}]]
+               {{{0,257,0},send},1},
+               {{{0,257,0},send,{'Result-Code',2001}},1}]}]]
 </pre>
 
 <p>
diff --git a/lib/diameter/doc/src/diameter_app.xml b/lib/diameter/doc/src/diameter_app.xml
index e6c9cc9a90..973b6eb732 100644
--- a/lib/diameter/doc/src/diameter_app.xml
+++ b/lib/diameter/doc/src/diameter_app.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="latin1" ?>
+<?xml version="1.0" encoding="utf-8" ?>
 <!DOCTYPE erlref SYSTEM "erlref.dtd" [
   <!ENTITY message '<seealso marker="#message">message()</seealso>'>
   <!ENTITY dict
@@ -13,20 +13,21 @@
 <header>
 
 <copyright>
-<year>2011</year><year>2013</year>
+<year>2011</year><year>2016</year>
 <holder>Ericsson AB. All Rights Reserved.</holder>
 </copyright>
 <legalnotice>
-The contents of this file are subject to the Erlang Public License,
-Version 1.1, (the "License"); you may not use this file except in
-compliance with the License. You should have received a copy of the
-Erlang Public License along with this software. If not, it can be
-retrieved online at http://www.erlang.org/.
-
-Software distributed under the License is distributed on an "AS IS"
-basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-the License for the specific language governing rights and limitations
-under the License.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+ 
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
 
 </legalnotice>
 
@@ -308,7 +309,7 @@ The return value <c>{Peer, NewState}</c> is only allowed if
 the Diameter application in question was configured with the
 &mod_application_opt; <c>{call_mutates_state, true}</c>.
 Otherwise, the <c>State</c> argument is always
-the intial value as configured on the application, not any subsequent
+the initial value as configured on the application, not any subsequent
 value returned by a &peer_up;
 or &peer_down; callback.</p>
 </warning>
@@ -565,7 +566,7 @@ Equivalent to</p>
 </pre>
 <p>
 where <c>Avps</c> sets the Origin-Host, Origin-Realm, the specified
-Result-Code and (if the request contained one) Session-Id AVP's, and
+Result-Code and (if the request contained one) Session-Id AVPs, and
 possibly Failed-AVP as described below.</p>
 
 <p>
diff --git a/lib/diameter/doc/src/diameter_codec.xml b/lib/diameter/doc/src/diameter_codec.xml
index 4a77d5435b..a0313e2877 100644
--- a/lib/diameter/doc/src/diameter_codec.xml
+++ b/lib/diameter/doc/src/diameter_codec.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="latin1" ?>
+<?xml version="1.0" encoding="utf-8" ?>
 <!DOCTYPE erlref SYSTEM "erlref.dtd" [
   <!ENTITY records
   '<seealso marker="diameter_dict#MESSAGE_RECORDS">diameter_dict(4)</seealso>'>
@@ -13,20 +13,21 @@
 <erlref>
 <header>
 <copyright>
-<year>2012</year>
+<year>2012</year><year>2016</year>
 <holder>Ericsson AB. All Rights Reserved.</holder>
 </copyright>
 <legalnotice>
-The contents of this file are subject to the Erlang Public License,
-Version 1.1, (the "License"); you may not use this file except in
-compliance with the License. You should have received a copy of the
-Erlang Public License along with this software. If not, it can be
-retrieved online at http://www.erlang.org/.
-
-Software distributed under the License is distributed on an "AS IS"
-basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-the License for the specific language governing rights and limitations
-under the License.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+ 
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
 
 </legalnotice>
 
@@ -73,7 +74,7 @@ are defined in diameter.hrl, which can be included as follows.</p>
 </pre>
 
 <p>
-Application-specific records are definied in the hrl
+Application-specific records are defined in the hrl
 files resulting from dictionary file compilation.</p>
 
 </description>
@@ -122,7 +123,7 @@ Fields have the following types.</p>
 <item>
 <p>
 Values in the AVP header, corresponding to AVP Code, the M flag, P
-flags and Vendor-ID respectivelty.
+flags and Vendor-ID respectively.
 A Vendor-ID other than <c>undefined</c> implies a set V flag.</p>
 </item>
 
@@ -222,7 +223,7 @@ header.</p>
 <tag><c>is_retransmitted = boolean()</c></tag>
 <item>
 <p>
-Values correspoding to the R(equest), P(roxiable), E(rror)
+Values corresponding to the R(equest), P(roxiable), E(rror)
 and T(Potentially re-transmitted message) flags of the Diameter
 header.</p>
 </item>
diff --git a/lib/diameter/doc/src/diameter_dict.xml b/lib/diameter/doc/src/diameter_dict.xml
index 4fcde495b3..ae40f99aee 100644
--- a/lib/diameter/doc/src/diameter_dict.xml
+++ b/lib/diameter/doc/src/diameter_dict.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="latin1" ?>
+<?xml version="1.0" encoding="utf-8" ?>
 <!DOCTYPE erlref SYSTEM "fileref.dtd" [
   <!ENTITY format
            '<seealso marker="#FILE_FORMAT">FILE FORMAT</seealso>'>
@@ -16,20 +16,21 @@
 <header>
 
 <copyright>
-<year>2011</year><year>2013</year>
+<year>2011</year><year>2016</year>
 <holder>Ericsson AB. All Rights Reserved.</holder>
 </copyright>
 <legalnotice>
-The contents of this file are subject to the Erlang Public License,
-Version 1.1, (the "License"); you may not use this file except in
-compliance with the License. You should have received a copy of the
-Erlang Public License along with this software. If not, it can be
-retrieved online at http://www.erlang.org/.
-
-Software distributed under the License is distributed on an "AS IS"
-basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-the License for the specific language governing rights and limitations
-under the License.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+ 
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
 
 </legalnotice>
 
@@ -431,7 +432,7 @@ equivalent to specifying it with <c>@avp_vendor_id</c>.</p>
 Defines values of AVP Name having type Enumerated.
 Section content consists of names and corresponding integer values.
 Integer values can be prefixed with 0x to be interpreted as
-hexidecimal.</p>
+hexadecimal.</p>
 
 <p>
 Note that the AVP in question can be defined in an inherited
@@ -529,6 +530,11 @@ answer record and passed to a &app_handle_request;
 callback upon reception of an incoming request.</p>
 
 <p>
+In cases in which there is a choice between string() and binary() types
+for OctetString() and derived types, the representation is determined
+by the value of &mod_string_decode;.</p>
+
+<p>
 <em>Basic AVP Data Formats</em></p>
 
 <marker id="OctetString"/>
@@ -541,7 +547,7 @@ callback upon reception of an incoming request.</p>
 <marker id="Grouped"/>
 
 <pre>
-OctetString() = [0..255]
+OctetString() = string() | binary()
 Integer32()   = -2147483647..2147483647
 Integer64()   = -9223372036854775807..9223372036854775807
 Unsigned32()  = 0..4294967295
@@ -603,13 +609,15 @@ and <c>{{2104,2,26},{9,42,23}}</c> (both inclusive) can be encoded.</p>
 
 <marker id="UTF8String"/>
 <pre>
-UTF8String() = [integer()]
+UTF8String() = [integer()] | binary()
 </pre>
 
 <p>
 List elements are the UTF-8 encodings of the individual characters
 in the string.
-Invalid codepoints will result in encode/decode failure.</p>
+Invalid codepoints will result in encode/decode failure.
+On encode, a UTF8String() can be specified as a binary, or as a nested
+list of binaries and codepoints.</p>
 
 <marker id="DiameterIdentity"/>
 <pre>
diff --git a/lib/diameter/doc/src/diameter_examples.xml b/lib/diameter/doc/src/diameter_examples.xml
index 1fd7755695..853ef96bb3 100644
--- a/lib/diameter/doc/src/diameter_examples.xml
+++ b/lib/diameter/doc/src/diameter_examples.xml
@@ -1,25 +1,26 @@
-<?xml version="1.0" encoding="latin1" ?>
+<?xml version="1.0" encoding="utf-8" ?>
 <!DOCTYPE chapter SYSTEM "chapter.dtd">
 
 <chapter>
 <header>
 
 <copyright>
-<year>2011</year><year>2012</year>
+<year>2011</year><year>2016</year>
 <holder>Ericsson AB. All Rights Reserved.</holder>
 </copyright>
 
 <legalnotice>
-The contents of this file are subject to the Erlang Public License,
-Version 1.1, (the "License"); you may not use this file except in
-compliance with the License. You should have received a copy of the
-Erlang Public License along with this software. If not, it can be
-retrieved online at http://www.erlang.org/.
-
-Software distributed under the License is distributed on an "AS IS"
-basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-the License for the specific language governing rights and limitations
-under the License.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+ 
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
 
 </legalnotice>
 
diff --git a/lib/diameter/doc/src/diameter_intro.xml b/lib/diameter/doc/src/diameter_intro.xml
index 288ebc0c7c..cb0aa3de2a 100644
--- a/lib/diameter/doc/src/diameter_intro.xml
+++ b/lib/diameter/doc/src/diameter_intro.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="latin1" ?>
+<?xml version="1.0" encoding="utf-8" ?>
 <!DOCTYPE chapter SYSTEM "chapter.dtd" [
   <!ENTITY % also SYSTEM "seealso.ent">
   %also;
@@ -7,21 +7,22 @@
 <chapter>
 <header>
 <copyright>
-<year>2011</year><year>2013</year>
+<year>2011</year><year>2016</year>
 <holder>Ericsson AB. All Rights Reserved.</holder>
 </copyright>
 
 <legalnotice>
-The contents of this file are subject to the Erlang Public License,
-Version 1.1, (the "License"); you may not use this file except in
-compliance with the License. You should have received a copy of the
-Erlang Public License along with this software. If not, it can be
-retrieved online at http://www.erlang.org/.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+ 
+    http://www.apache.org/licenses/LICENSE-2.0
 
-Software distributed under the License is distributed on an "AS IS"
-basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-the License for the specific language governing rights and limitations
-under the License.
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
 
 </legalnotice>
 
@@ -40,7 +41,7 @@ under the License.
 The diameter application is an implementation of the Diameter protocol
 as defined by &the_rfc;.
 It supports arbitrary Diameter applications by way of a
-<em>dictionary</em> interface that allows messages and AVP's to be
+<em>dictionary</em> interface that allows messages and AVPs to be
 defined and input into diameter as configuration.
 It has support for all roles defined in the RFC: client, server and
 agent.
@@ -69,7 +70,7 @@ interface</seealso>.</p>
 <p>
 While a service typically implements a single Diameter node (as
 identified by an Origin-Host AVP), transports can themselves be
-associated with capabilities AVP's so that a single service can be
+associated with capabilities AVPs so that a single service can be
 used to implement more than one Diameter node.</p>
 
 <p>
diff --git a/lib/diameter/doc/src/diameter_make.xml b/lib/diameter/doc/src/diameter_make.xml
index ec71251be1..112355816f 100644
--- a/lib/diameter/doc/src/diameter_make.xml
+++ b/lib/diameter/doc/src/diameter_make.xml
@@ -1,5 +1,7 @@
-<?xml version="1.0" encoding="latin1" ?>
+<?xml version="1.0" encoding="utf-8" ?>
 <!DOCTYPE erlref SYSTEM "erlref.dtd" [
+  <!ENTITY compile_forms2
+  '<seealso marker="compiler:compile#forms-2">compile:forms/2</seealso>'>
   <!ENTITY filename
   '<seealso marker="kernel:file#type-name">file:name()</seealso>'>
   <!ENTITY dictionary
@@ -14,20 +16,21 @@
 <header>
 <copyright>
 <year>2012</year>
-<year>2013</year>
+<year>2016</year>
 <holder>Ericsson AB. All Rights Reserved.</holder>
 </copyright>
 <legalnotice>
-The contents of this file are subject to the Erlang Public License,
-Version 1.1, (the "License"); you may not use this file except in
-compliance with the License. You should have received a copy of the
-Erlang Public License along with this software. If not, it can be
-retrieved online at http://www.erlang.org/.
-
-Software distributed under the License is distributed on an "AS IS"
-basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-the License for the specific language governing rights and limitations
-under the License.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+ 
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
 
 </legalnotice>
 
@@ -50,8 +53,8 @@ under the License.
 <p>
 The function &codec; is used to compile a diameter
 &dictionary; into Erlang source.
-The resulting source implements the interface diameter required
-to encode and decode the dictionary's messages and AVP's.</p>
+The resulting source implements the interface diameter requires
+to encode and decode the dictionary's messages and AVPs.</p>
 
 <p>
 The utility &man_compile; provides an alternate compilation
@@ -64,16 +67,47 @@ interface.</p>
 <funcs>
 
 <func>
-<name>codec(Path::string(), [Opt]) -> ok | {error, Reason}</name>
+<name>codec(File :: iolist() | binary(), [Opt]) -> ok
+                                                 | {ok, [Out]}
+                                                 | {error, Reason}</name>
 <fsummary>Compile a dictionary file into Erlang source.</fsummary>
 <desc>
 
 <p>
-Compile a single dictionary file to Erlang source.
-<c>Opt</c> can have the following types.</p>
+Compile a single dictionary file.
+The input <c>File</c> can be either a path or a literal dictionary,
+the occurrence of newline (ascii NL) or carriage return (ascii CR)
+identifying the latter.
+<c>Opt</c> determines the format of the results and whether they are
+written to file or returned, and can have the following types.</p>
 
 <taglist>
 
+<tag><c>parse | forms | erl | hrl</c></tag>
+<item>
+<p>
+Specifies an output format.
+Whether the output is returned or written to file depends on whether
+or not option <c>return</c> is specified.
+When written to file, the resulting file(s) will have extensions
+<c>.D</c>, <c>.F</c>, <c>.erl</c>, and <c>.hrl</c>
+respectively, basenames defaulting to <c>dictionary</c> if the input
+dictionary is literal and does not specify <c>&dict_name;</c>.
+When returned, results are in the order of the corresponding format
+options.
+Format options default to <c>erl</c> and <c>hrl</c> (in this order) if
+unspecified.</p>
+
+<p>
+The <c>parse</c> format is an internal representation that can be
+passed to &flatten; and &format;, while the <c>forms</c> format can be
+passed to &compile_forms2;.
+The <c>erl</c> and <c>hrl</c> formats are returned as
+iolists.</p>
+<!-- That codec/2 can take the parsed format is undocumented, and
+     options name and inherits have no effect in this case. -->
+</item>
+
 <tag><c>{include, string()}</c></tag>
 <item>
 <p>
@@ -90,7 +124,15 @@ Multiple <c>include</c> options can be specified.</p>
 <item>
 <p>
 Write generated source to the specified directory.
-Defaults to the current working directory.</p>
+Defaults to the current working directory.
+Has no effect if option <c>return</c> is specified.</p>
+</item>
+
+<tag><c>return</c></tag>
+<item>
+<p>
+Return results in a <c>{ok, [Out]}</c> tuple instead of writing to
+file and returning <c>ok</c>.</p>
 </item>
 
 <tag><c>{name|prefix, string()}</c></tag>
@@ -108,7 +150,7 @@ Transform the input dictionary before compilation, appending
 <c>&dict_inherits;</c> of the specified string.</p>
 
 <p>
-Two forms of <c>@inherits</c> have special meaning:</p>
+Two forms have special meaning:</p>
 
 <pre>
 {inherits, "-"}
@@ -127,6 +169,57 @@ Multiple <c>inherits</c> options can be specified.</p>
 
 </taglist>
 
+<p>
+Note that a dictionary's <c>&dict_name;</c>, together with the
+<c>outdir</c> option, determine the output paths when the
+<c>return</c> option is not specified.
+The <c>&dict_name;</c> of a literal input dictionary defaults to
+<c>dictionary</c>.</p>
+
+<p>
+A returned error reason can be converted into a readable string using
+&format_error;.</p>
+
+</desc>
+</func>
+
+<!-- ===================================================================== -->
+
+<func>
+<name>format(Parsed) -> iolist()</name>
+<fsummary>Format a parsed dictionary.</fsummary>
+<desc>
+<p>
+Turns a parsed dictionary, as returned by &codec;, back into the
+dictionary format.</p>
+</desc>
+</func>
+
+<!-- ===================================================================== -->
+
+<func>
+<name>flatten(Parsed) -> term()</name>
+<fsummary>Flatten a parsed dictionary.</fsummary>
+<desc>
+
+<p>
+Reconstitute a parsed dictionary, as returned by &codec;, without
+using <c>&dict_inherits;</c>.
+That is, construct an equivalent dictionary in which all AVP's are
+definined in the dictionary itself.
+The return value is also a parsed dictionary.</p>
+</desc>
+</func>
+
+<!-- ===================================================================== -->
+
+<func>
+<name>format_error(Reason) -> string()</name>
+<fsummary>Turn an error reason into a readable string.</fsummary>
+<desc>
+
+<p>
+Turn an error reason returned by &codec; into a readable string.</p>
 </desc>
 </func>
 
@@ -138,11 +231,7 @@ Multiple <c>inherits</c> options can be specified.</p>
 <title>BUGS</title>
 
 <p>
-All options are string-valued.
-In particular, it is not currently possible to specify
-an &dict_inherits; module as an atom(), or a path as an arbitrary
-&filename;</p>
-
+Unrecognized options are silently ignored.</p>
 </section>
 
 <!-- ===================================================================== -->
diff --git a/lib/diameter/doc/src/diameter_sctp.xml b/lib/diameter/doc/src/diameter_sctp.xml
index 5fe14b1ef6..9b6d629f79 100644
--- a/lib/diameter/doc/src/diameter_sctp.xml
+++ b/lib/diameter/doc/src/diameter_sctp.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="latin1" ?>
+<?xml version="1.0" encoding="utf-8" ?>
 <!DOCTYPE erlref SYSTEM "erlref.dtd" [
   <!ENTITY gen_sctp '<seealso marker="kernel:gen_sctp">gen_sctp(3)</seealso>'>
   <!ENTITY gen_sctp_open1
@@ -15,20 +15,22 @@
 <erlref>
 <header>
 <copyright>
-<year>2011</year><year>2013</year>
+<year>2011</year>
+<year>2016</year>
 <holder>Ericsson AB. All Rights Reserved.</holder>
 </copyright>
 <legalnotice>
-The contents of this file are subject to the Erlang Public License,
-Version 1.1, (the "License"); you may not use this file except in
-compliance with the License. You should have received a copy of the
-Erlang Public License along with this software. If not, it can be
-retrieved online at http://www.erlang.org/.
-
-Software distributed under the License is distributed on an "AS IS"
-basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-the License for the specific language governing rights and limitations
-under the License.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+ 
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
 
 </legalnotice>
 
@@ -90,7 +92,7 @@ Options <c>raddr</c> and <c>rport</c> specify the remote address
 and port for a connecting transport and not valid for a listening
 transport: the former is required while latter defaults to 3868 if
 unspecified.
-Mupltiple <c>raddr</c> options can be specified, in which case the
+Multiple <c>raddr</c> options can be specified, in which case the
 connecting transport in question attempts each in sequence until
 an association is established.</p>
 
@@ -113,7 +115,7 @@ and port respectively.</p>
 <p>
 Multiple <c>ip</c> options can be specified for a multihomed peer.
 If none are specified then the values of <c>Host-IP-Address</c>
-in the <c>#diameter_service{}</c> record are used.
+in the <c>diameter_service</c> record are used.
 (In particular, one of these must be specified.)
 Option <c>port</c> defaults to 3868 for a listening transport and 0 for a
 connecting transport.</p>
@@ -131,25 +133,18 @@ the buffer size.</p>
 </warning>
 
 <p>
-diameter_sctp uses the <c>transport_data</c> field of
-the <c>#diameter_packet{}</c> record to communicate the stream on which an
-inbound message has been received, or on which an outbound message
-should be sent: the value will be of the form <c>{stream, Id}</c>
-on an inbound message passed to a &app_handle_request; or
-&app_handle_answer; callback.
-For an outbound message, either <c>undefined</c> (explicitly or
-by receiving the outbound message as a <c>binary()</c>) or a tuple
-should be set in the return value of &app_handle_request;
-(typically by retaining the value passed into this function)
-or &app_prepare_request;.
-The value <c>undefined</c> uses a "next outbound stream" id and
-increments this modulo the total number outbound streams.
-That is, successive values of <c>undefined</c> cycle through all
-outbound streams.</p>
-
-<!-- TODO: Some way of getting at the number of available outbound -->
-<!--       streams.                                                -->
-
+The <c>transport_data</c> field of record <c>diameter_packet</c>
+is used to communicate the stream on which an inbound message
+has been received, or on which an outbound message should be sent.
+The value will be of the form <c>{stream, Id}</c> for an inbound
+message passed to a &app_handle_request; or &app_handle_answer;
+callback.
+For an outbound message, <c>{outstream, Id}</c> in the return value of
+&app_handle_request; or &app_prepare_retransmit; sets the outbound
+stream, the stream id being interpreted modulo the number of outbound
+streams.
+Any other value, or not setting a value, causes successive such sends
+to cycle though all outbound streams.</p>
 </desc>
 </func>
 
diff --git a/lib/diameter/doc/src/diameter_soc.xml b/lib/diameter/doc/src/diameter_soc.xml
index 4f5419122f..ae404fcda4 100644
--- a/lib/diameter/doc/src/diameter_soc.xml
+++ b/lib/diameter/doc/src/diameter_soc.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="latin1" ?>
+<?xml version="1.0" encoding="utf-8" ?>
 <!DOCTYPE chapter SYSTEM "chapter.dtd" [
   <!ENTITY % also SYSTEM "seealso.ent" >
   %also;
@@ -9,21 +9,22 @@
 <header>
 <copyright>
 <year>2011</year>
-<year>2013</year>
+<year>2016</year>
 <holder>Ericsson AB. All Rights Reserved.</holder>
 </copyright>
 
 <legalnotice>
-The contents of this file are subject to the Erlang Public License,
-Version 1.1, (the "License"); you may not use this file except in
-compliance with the License. You should have received a copy of the
-Erlang Public License along with this software. If not, it can be
-retrieved online at http://www.erlang.org/.
-
-Software distributed under the License is distributed on an "AS IS"
-basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-the License for the specific language governing rights and limitations
-under the License.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+ 
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
 
 </legalnotice>
 
diff --git a/lib/diameter/doc/src/diameter_soc_rfc6733.xml b/lib/diameter/doc/src/diameter_soc_rfc6733.xml
index 8d85569650..2098965706 100644
--- a/lib/diameter/doc/src/diameter_soc_rfc6733.xml
+++ b/lib/diameter/doc/src/diameter_soc_rfc6733.xml
@@ -1,23 +1,24 @@
-<?xml version="1.0" encoding="latin1" ?>
+<?xml version="1.0" encoding="utf-8" ?>
 
 <!--
 
 <copyright>
-<year>2013</year>
+<year>2013</year><year>2016</year>
 <holder>Ericsson AB. All Rights Reserved.</holder>
 </copyright>
 
 <legalnotice>
-The contents of this file are subject to the Erlang Public License,
-Version 1.1, (the "License"); you may not use this file except in
-compliance with the License. You should have received a copy of the
-Erlang Public License along with this software. If not, it can be
-retrieved online at http://www.erlang.org/.
-
-Software distributed under the License is distributed on an "AS IS"
-basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-the License for the specific language governing rights and limitations
-under the License.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+ 
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
 
 </legalnotice>
 
@@ -1272,7 +1273,7 @@ during capabilities exchange.)</p>
 
 <p>
 The frequency of reconnection attempts is configured with the
-&mod_transport_opt; <c>reconnect_timer</c> and
+&mod_transport_opt; <c>connect_timer</c> and
 <c>watchdog_timer</c>.</p>
 
 <pre>
diff --git a/lib/diameter/doc/src/diameter_tcp.xml b/lib/diameter/doc/src/diameter_tcp.xml
index ce4d6cfd0f..00ccc39c15 100644
--- a/lib/diameter/doc/src/diameter_tcp.xml
+++ b/lib/diameter/doc/src/diameter_tcp.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="latin1" ?>
+<?xml version="1.0" encoding="utf-8" ?>
 <!DOCTYPE erlref SYSTEM "erlref.dtd" [
   <!ENTITY start '<seealso marker="#start-3">start/3</seealso>'>
   <!ENTITY gen_tcp_connect3
@@ -27,20 +27,21 @@
 <erlref>
 <header>
 <copyright>
-<year>2011</year><year>2013</year>
+<year>2011</year><year>2016</year>
 <holder>Ericsson AB. All Rights Reserved.</holder>
 </copyright>
 <legalnotice>
-The contents of this file are subject to the Erlang Public License,
-Version 1.1, (the "License"); you may not use this file except in
-compliance with the License. You should have received a copy of the
-Erlang Public License along with this software. If not, it can be
-retrieved online at http://www.erlang.org/.
-
-Software distributed under the License is distributed on an "AS IS"
-basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-the License for the specific language governing rights and limitations
-under the License.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+ 
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
 
 </legalnotice>
 
diff --git a/lib/diameter/doc/src/diameter_transport.xml b/lib/diameter/doc/src/diameter_transport.xml
index 9161bd1f48..736d4cbfbd 100644
--- a/lib/diameter/doc/src/diameter_transport.xml
+++ b/lib/diameter/doc/src/diameter_transport.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="latin1" ?>
+<?xml version="1.0" encoding="utf-8" ?>
 <!DOCTYPE erlref SYSTEM "erlref.dtd" [
   <!ENTITY message '<seealso marker="#message">message()</seealso>'>
   <!ENTITY MESSAGES '<seealso marker="#MESSAGES">MESSAGES</seealso>'>
@@ -14,20 +14,21 @@
 <erlref>
 <header>
 <copyright>
-<year>2011</year><year>2013</year>
+<year>2011</year><year>2016</year>
 <holder>Ericsson AB. All Rights Reserved.</holder>
 </copyright>
 <legalnotice>
-The contents of this file are subject to the Erlang Public License,
-Version 1.1, (the "License"); you may not use this file except in
-compliance with the License. You should have received a copy of the
-Erlang Public License along with this software. If not, it can be
-retrieved online at http://www.erlang.org/.
-
-Software distributed under the License is distributed on an "AS IS"
-basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-the License for the specific language governing rights and limitations
-under the License.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+ 
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
 
 </legalnotice>
 
diff --git a/lib/diameter/doc/src/diameter_using.xml b/lib/diameter/doc/src/diameter_using.xml
index c487d94a16..dbdb1be284 100644
--- a/lib/diameter/doc/src/diameter_using.xml
+++ b/lib/diameter/doc/src/diameter_using.xml
@@ -1,25 +1,26 @@
-<?xml version="1.0" encoding="latin1" ?>
+<?xml version="1.0" encoding="utf-8" ?>
 <!DOCTYPE chapter SYSTEM "chapter.dtd">
 
 <chapter>
 
 <header>
 <copyright>
-<year>2011</year><year>2013</year>
+<year>2011</year><year>2016</year>
 <holder>Ericsson AB. All Rights Reserved.</holder>
 </copyright>
 
 <legalnotice>
-The contents of this file are subject to the Erlang Public License,
-Version 1.1, (the "License"); you may not use this file except in
-compliance with the License. You should have received a copy of the
-Erlang Public License along with this software. If not, it can be
-retrieved online at http://www.erlang.org/.
-
-Software distributed under the License is distributed on an "AS IS"
-basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-the License for the specific language governing rights and limitations
-under the License.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+ 
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
 
 </legalnotice>
 
diff --git a/lib/diameter/doc/src/diameter_compile.xml b/lib/diameter/doc/src/diameterc.xml
index 6630019e5c..5bffe9a771 100644
--- a/lib/diameter/doc/src/diameter_compile.xml
+++ b/lib/diameter/doc/src/diameterc.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="iso-8859-1" ?>
+<?xml version="1.0" encoding="utf-8" ?>
 <!DOCTYPE comref SYSTEM "comref.dtd" [
   <!ENTITY dictionary
   '<seealso marker="diameter_dict">dictionary file</seealso>'>
@@ -29,7 +29,7 @@ supplied.
 <docno></docno>
 <date></date>
 <rev></rev>
-<file>diameter_compile.xml</file>
+<file>diameterc.xml</file>
 </header>
 
 <com>diameterc</com>
@@ -41,7 +41,7 @@ supplied.
 The diameterc utility is used to compile a diameter
 &dictionary; into Erlang source.
 The resulting source implements the interface diameter required
-to encode and decode the dictionary's messages and AVP's.</p>
+to encode and decode the dictionary's messages and AVPs.</p>
 
 <p>
 The module &man_make; provides an alternate compilation interface.</p>
@@ -83,7 +83,7 @@ Defaults to the current working directory.</p>
 <tag><![CDATA[-H]]></tag>
 <item>
 <p>
-Supress erl and hrl generation, respectively.</p>
+Suppress erl and hrl generation, respectively.</p>
 </item>
 
 <tag><![CDATA[--name <name>]]></tag>
diff --git a/lib/diameter/doc/src/files.mk b/lib/diameter/doc/src/files.mk
index 510786a7fb..cb4f88a375 100644
--- a/lib/diameter/doc/src/files.mk
+++ b/lib/diameter/doc/src/files.mk
@@ -2,18 +2,19 @@
 
 # %CopyrightBegin%
 #
-# Copyright Ericsson AB 2010-2013. All Rights Reserved.
+# Copyright Ericsson AB 2010-2016. All Rights Reserved.
 #
-# The contents of this file are subject to the Erlang Public License,
-# Version 1.1, (the "License"); you may not use this file except in
-# compliance with the License. You should have received a copy of the
-# Erlang Public License along with this software. If not, it can be
-# retrieved online at http://www.erlang.org/.
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
 #
-# Software distributed under the License is distributed on an "AS IS"
-# basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-# the License for the specific language governing rights and limitations
-# under the License.
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
 #
 # %CopyrightEnd%
 
@@ -21,7 +22,7 @@ XML_APPLICATION_FILES = \
 	ref_man.xml
 
 XML_REF1_FILES = \
-	diameter_compile.xml
+	diameterc.xml
 
 XML_REF3_FILES = \
 	diameter.xml \
diff --git a/lib/diameter/doc/src/notes.xml b/lib/diameter/doc/src/notes.xml
index e750b56f1e..b1be7bdcf7 100644
--- a/lib/diameter/doc/src/notes.xml
+++ b/lib/diameter/doc/src/notes.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="latin1" ?>
+<?xml version="1.0" encoding="utf-8" ?>
 <!DOCTYPE chapter SYSTEM "chapter.dtd" [
   <!ENTITY % also SYSTEM "seealso.ent" >
   <!ENTITY % here SYSTEM "seehere.ent" >
@@ -11,20 +11,21 @@
 <header>
 <copyright>
 <year>2011</year>
-<year>2013</year>
+<year>2016</year>
 <holder>Ericsson AB. All Rights Reserved.</holder>
 </copyright>
 <legalnotice>
-The contents of this file are subject to the Erlang Public License,
-Version 1.1, (the "License"); you may not use this file except in
-compliance with the License. You should have received a copy of the
-Erlang Public License along with this software. If not, it can be
-retrieved online at http://www.erlang.org/.
-
-Software distributed under the License is distributed on an "AS IS"
-basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-the License for the specific language governing rights and limitations
-under the License.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+ 
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
 
 </legalnotice>
 
@@ -42,6 +43,1058 @@ first.</p>
 
 <!-- ===================================================================== -->
 
+<section><title>diameter 1.12</title>
+
+    <section><title>Fixed Bugs and Malfunctions</title>
+      <list>
+        <item>
+          <p>
+	    Ensure listening socket is closed at transport removal.</p>
+          <p>
+	    Transport removal did not immediately close a
+	    <c>diameter_tcp/sctp</c> listening socket, and a
+	    subsequent peer connection caused it to remain open.</p>
+          <p>
+	    Own Id: OTP-13611</p>
+        </item>
+      </list>
+    </section>
+
+
+    <section><title>Improvements and New Features</title>
+      <list>
+        <item>
+          <p>
+	    Add <c>diameter:peer_info/1</c>.</p>
+          <p>
+	    That retrieves information in the style of
+	    <c>diameter:service_info/2</c>, but for a single peer
+	    connection.</p>
+          <p>
+	    Own Id: OTP-13508</p>
+        </item>
+      </list>
+    </section>
+
+</section>
+
+<section><title>diameter 1.11.2</title>
+
+    <section><title>Fixed Bugs and Malfunctions</title>
+      <list>
+        <item>
+          <p>
+	    Make peer handling more efficient.</p>
+          <p>
+	    Inefficient lookup and manipulation of peer lists could
+	    result in poor performance when many outgoing requests
+	    were sent simultaneously, or when many peers connected
+	    simultaneously. Filtering peer lists on realm/host is now
+	    also more efficient in many cases.</p>
+          <p>
+	    Own Id: OTP-13164</p>
+        </item>
+        <item>
+          <p>
+	    Fix handling of shared peer connections in watchdog state
+	    SUSPECT.</p>
+          <p>
+	    A peer connection shared from a remote node was regarded
+	    as being up for the lifetime of the connection, ignoring
+	    watchdog transitions into state SUSPECT.</p>
+          <p>
+	    Own Id: OTP-13342</p>
+        </item>
+      </list>
+    </section>
+
+</section>
+
+<section><title>diameter 1.11.1</title>
+
+    <section><title>Fixed Bugs and Malfunctions</title>
+      <list>
+        <item>
+          <p>
+	    Fix request table leaks</p>
+          <p>
+	    The End-to-End and Hop-by-Hop identifiers of outgoing
+	    Diameter requests are stored in a table in order for the
+	    caller to be located when the corresponding answer
+	    message is received. Entries were orphaned if the handler
+	    was terminated by an exit signal as a consequence of
+	    actions taken by callback functions, or if callbacks
+	    modified identifiers in retransmission cases.</p>
+          <p>
+	    Own Id: OTP-13137</p>
+        </item>
+      </list>
+    </section>
+
+</section>
+
+<section><title>diameter 1.11</title>
+
+    <section><title>Fixed Bugs and Malfunctions</title>
+      <list>
+        <item>
+          <p>
+	    Fix relay encode of nested, Grouped AVPs.</p>
+          <p>
+	    A fault in OTP-12475 caused encode to fail if the first
+	    AVP in a Grouped AVP was itself Grouped.</p>
+          <p>
+	    Own Id: OTP-12879 Aux Id: OTP-12475 </p>
+        </item>
+        <item>
+          <p>
+	    Match acceptable peer addresses case insensitively.</p>
+          <p>
+	    Regular expressions passed in an 'accept' tuple to
+	    diameter_tcp or diameter_sctp inappropriately matched
+	    case.</p>
+          <p>
+	    Own Id: OTP-12902</p>
+        </item>
+        <item>
+          <p>
+	    Fix diameter_watchdog function clause.</p>
+          <p>
+	    OTP-12912 introduced an error with accepting transports
+	    setting <c>{restrict_connections, false}</c>, causing
+	    processes to fail when peer connections were terminated.</p>
+          <p>
+	    Own Id: OTP-12969</p>
+        </item>
+      </list>
+    </section>
+
+
+    <section><title>Improvements and New Features</title>
+      <list>
+        <item>
+          <p>
+	    Don't report 5005 (DIAMETER_AVP_MISSING) errors
+	    unnecessarily.</p>
+          <p>
+	    An AVP whose decode failed was reported as missing,
+	    despite having been reported with another error as a
+	    consequence of the failure.</p>
+          <p>
+	    Own Id: OTP-12871</p>
+        </item>
+        <item>
+          <p>
+	    Improve decode performance.</p>
+          <p>
+	    The time required to decode a message increased
+	    quadratically with the number of AVPs in the worst case,
+	    leading to extremely long execution times.</p>
+          <p>
+	    Own Id: OTP-12891</p>
+        </item>
+        <item>
+          <p>
+	    Improve watchdog and statistics performance.</p>
+          <p>
+	    Inefficient use of timers contributed to poor performance
+	    at high load, as did ordering of the table statistics are
+	    written to.</p>
+          <p>
+	    Own Id: OTP-12912</p>
+        </item>
+        <item>
+          <p>
+	    Add service_opt() strict_mbit.</p>
+          <p>
+	    There are differing opinions on whether or not reception
+	    of an arbitrary AVP setting the M-bit is an error. The
+	    default interpretation is strict: if a command grammar
+	    doesn't explicitly allow an AVP setting the M-bit then
+	    reception of such an AVP is regarded as an error. Setting
+	    <c>{strict_mbit, false}</c> disables this check.</p>
+          <p>
+	    Own Id: OTP-12947</p>
+        </item>
+      </list>
+    </section>
+
+</section>
+
+<section><title>diameter 1.10</title>
+
+    <section><title>Fixed Bugs and Malfunctions</title>
+      <list>
+        <item>
+          <p>
+	    Fix decode of Grouped AVPs containing errors.</p>
+          <p>
+	    RFC 6733 says this of Failed-AVP in 7.5:</p>
+          <p>
+	    <taglist><item><p><c> In the case where the offending AVP
+	    is embedded within a Grouped AVP, the Failed-AVP MAY
+	    contain the grouped AVP, which in turn contains the
+	    single offending AVP. The same method MAY be employed if
+	    the grouped AVP itself is embedded in yet another grouped
+	    AVP and so on. In this case, the Failed-AVP MAY contain
+	    the grouped AVP hierarchy up to the single offending AVP.
+	    This enables the recipient to detect the location of the
+	    offending AVP when embedded in a
+	    group.</c></p></item></taglist></p>
+          <p>
+	    It says this of DIAMETER_INVALID_AVP_LENGTH in 7.1.5:</p>
+          <p>
+	    <taglist><item><p><c> The request contained an AVP with
+	    an invalid length. A Diameter message indicating this
+	    error MUST include the offending AVPs within a Failed-AVP
+	    AVP. In cases where the erroneous AVP length value
+	    exceeds the message length or is less than the minimum
+	    AVP header length, it is sufficient to include the
+	    offending AVP header and a zero filled payload of the
+	    minimum required length for the payloads data type. If
+	    the AVP is a Grouped AVP, the Grouped AVP header with an
+	    empty payload would be sufficient to indicate the
+	    offending AVP. In the case where the offending AVP header
+	    cannot be fully decoded when the AVP length is less than
+	    the minimum AVP header length, it is sufficient to
+	    include an offending AVP header that is formulated by
+	    padding the incomplete AVP header with zero up to the
+	    minimum AVP header length.</c></p></item></taglist></p>
+          <p>
+	    The AVPs placed in the errors field of a diameter_packet
+	    record are intended to be appropriate for inclusion in a
+	    Failed-AVP, but neither of the above paragraphs has been
+	    followed in the Grouped case: the entire faulty AVP
+	    (non-faulty components and all) has been included. This
+	    made it difficult to identify the actual faulty AVP in
+	    all but simple cases.</p>
+          <p>
+	    The decode is now adapted to the RFC, and implements the
+	    suggested single faulty AVP, nested in as many Grouped
+	    containers as required.</p>
+          <p>
+	    Own Id: OTP-12721</p>
+        </item>
+        <item>
+          <p>
+	    Fix SCTP problems on Solaris.</p>
+          <p>
+	    The allocation of association ids in Solaris was in
+	    conflict with an assumption made in diameter_sctp,
+	    resulting in failures when accepting multiple peer
+	    connections.</p>
+          <p>
+	    Own Id: OTP-12768</p>
+        </item>
+        <item>
+          <p>
+	    Fix start order of alternate transports.</p>
+          <p>
+	    A transport configured with diameter:add_transport/2 can
+	    be passed multiple transport_module/transport_config
+	    tuples in order to specify alternate configuration,
+	    modules being attempted in order until one succeeds. This
+	    is primarily for the connecting case; for example, to
+	    allow a transport to be configured to first attempt
+	    connection over SCTP, and then TCP in case SCTP fails.
+	    Multiple module tuples can be paired with a single config
+	    tuple, but in this case the start order was reversed
+	    relative to the order in which the modules were specifed.</p>
+          <p>
+	    Own Id: OTP-12851</p>
+        </item>
+      </list>
+    </section>
+
+
+    <section><title>Improvements and New Features</title>
+      <list>
+        <item>
+          <p>
+	    Change license text from Erlang Public License to Apache
+	    Public License v2.</p>
+          <p>
+	    Own Id: OTP-12845</p>
+        </item>
+      </list>
+    </section>
+
+</section>
+
+<section><title>diameter 1.9.2</title>
+
+    <section><title>Fixed Bugs and Malfunctions</title>
+      <list>
+        <item>
+          <p>
+	    Fix broken relay counters.</p>
+          <p>
+	    OTP-12654 in OTP 17.5.3 broke counters in the case of
+	    answer messages received in the relay application.
+	    Counters were accumulated as unknown messages or
+	    no_result_code instead of as relayed messages on the
+	    intended Result-Code and 'Experimental-Result' tuples.</p>
+          <p>
+	    Own Id: OTP-12741</p>
+        </item>
+        <item>
+          <p>
+	    Fix diameter_sctp listener race.</p>
+          <p>
+	    An oversight in OTP-12428 made it possible to start a
+	    transport process that could not establish associations.</p>
+          <p>
+	    Own Id: OTP-12744</p>
+        </item>
+      </list>
+    </section>
+
+</section>
+
+<section><title>diameter 1.9.1</title>
+
+    <section><title>Known Bugs and Problems</title>
+      <list>
+        <item>
+          <p>
+	    Don't leave extra bit in decoded AVP data.</p>
+          <p>
+	    OTP-12074 in OTP 17.3 missed one case: a length error on
+	    a trailing AVP unknown to the dictionary in question.</p>
+          <p>
+	    Own Id: OTP-12642</p>
+        </item>
+        <item>
+          <p>
+	    Don't confuse Result-Code and Experimental-Result.</p>
+          <p>
+	    The errors field of a decoded diameter_packet record was
+	    populated with a Result-Code AVP when an
+	    Experimental-Result containing a 3xxx Result-Code was
+	    received in an answer not setting the E-bit. The correct
+	    AVP is now extracted from the incoming message.</p>
+          <p>
+	    Own Id: OTP-12654</p>
+        </item>
+        <item>
+          <p>
+	    Don't count on unknown Application Id.</p>
+          <p>
+	    OTP-11721 in OTP 17.1 missed the case of an Application
+	    Id not agreeing with that of the dictionary in question,
+	    causing counters to be accumulated on keys containing the
+	    unknown id.</p>
+          <p>
+	    Own Id: OTP-12701</p>
+        </item>
+      </list>
+    </section>
+
+</section>
+
+<section><title>diameter 1.9</title>
+
+    <section><title>Fixed Bugs and Malfunctions</title>
+      <list>
+        <item>
+          <p>
+	    Don't discard outgoing answers unnecessarily.</p>
+          <p>
+	    Answers missing a Result-Code AVP or setting an E-bit
+	    inappropriately were discarded even if encode was
+	    successful.</p>
+          <p>
+	    Own Id: OTP-11492</p>
+        </item>
+        <item>
+          <p>
+	    Increase supervision timeouts.</p>
+          <p>
+	    At diameter application shutdown, DPR could be omitted on
+	    open peer connections because of short supervision
+	    timeouts.</p>
+          <p>
+	    Own Id: OTP-12412</p>
+        </item>
+        <item>
+          <p>
+	    Fix retransmission of messages sent as header/avps list.</p>
+          <p>
+	    Extracting End-to-End and Hop-by-Hop Identifiers resulted
+	    in a function clause error, resulting in a handle_error
+	    callback.</p>
+          <p>
+	    Own Id: OTP-12415</p>
+        </item>
+        <item>
+          <p>
+	    Fix diameter_avp decode of Grouped AVPs having decode
+	    errors.</p>
+          <p>
+	    Components of such an AVP were not extracted, causing it
+	    to be represented by a single diameter_avp record instead
+	    of the intended list.</p>
+          <p>
+	    Dictionary files must be recompiled for the fix to have
+	    effect.</p>
+          <p>
+	    Own Id: OTP-12475</p>
+        </item>
+        <item>
+          <p>
+	    Fix ordering of AVPs in relayed messages.</p>
+          <p>
+	    The order was reversed relative to the received order,
+	    with a Route-Record AVP prepended.</p>
+          <p>
+	    Thanks to Andrzej Trawiński.</p>
+          <p>
+	    Own Id: OTP-12551</p>
+        </item>
+        <item>
+          <p>
+	    Fix issues with DiameterURI encode/decode.</p>
+          <p>
+	    RFC 6773 changed the default port and transport, but the
+	    RFC 3588 defaults were used even if the RFC 6733 common
+	    dictionary was in use. The RFC 3588 defaults are now only
+	    used when the common dictionary is
+	    diameter_gen_base_rfc3588.</p>
+          <p>
+	    Both RFC 3588 and 6733 disallow
+	    transport=udp;protocol=diameter. Encode of the
+	    combination now fails.</p>
+          <p>
+	    Decode of ports numbers outside the range 0-65535 and
+	    fully qualified domain names longer than 255 octets now
+	    fails.</p>
+          <p>
+	    Note that RFC 3588 is obsolete, and that there is a
+	    diameter_gen_base_rfc6733. The change in defaults is a
+	    potential interoperability problem when moving to RFC
+	    6733 with peers that do not send all URI components. The
+	    fact that 6733 allows 5xxx result codes in answer
+	    messages setting the E-bit, which RFC 3588 doesn't, is
+	    another.</p>
+          <p>
+	    Own Id: OTP-12589</p>
+        </item>
+      </list>
+    </section>
+
+
+    <section><title>Improvements and New Features</title>
+      <list>
+        <item>
+          <p>
+	    Add service_opt() string_decode.</p>
+          <p>
+	    To disable the decode of potentially large binaries to
+	    string. This prevents large strings from being copied
+	    when incoming Diameter messages are passed between
+	    processes, a vulnerability that can lead to memory being
+	    exhausted given sufficiently malicious peers.</p>
+          <p>
+	    The value is a boolean(), true being the default for
+	    backwards compatibility. Setting false causes both
+	    diameter_caps records and decoded messages to contain
+	    binary() in relevant places that previously had string():
+	    diameter_app(3) callbacks need to be prepared for the
+	    change.</p>
+          <p>
+	    The Diameter types affected are OctetString and the
+	    derived types UTF8String, DiameterIdentity, DiameterURI,
+	    IPFilterRule, and QoSFilterRule. Time and Address are
+	    unaffected.</p>
+          <p>
+	    Own Id: OTP-11952</p>
+        </item>
+        <item>
+          <p>
+	    Add transport_opt() pool_size.</p>
+          <p>
+	    To allow for pools of accepting transport processes,
+	    which can better service multiple simultaneous peer
+	    connections. The option can also be used with connecting
+	    transports, to establish multiple connections to the same
+	    peer without having to configure multiple transports.</p>
+          <p>
+	    Own Id: OTP-12428</p>
+        </item>
+        <item>
+          <p>
+	    Allow DPR to be sent with diameter:call/4.</p>
+          <p>
+	    It has been possible to send, but the answer was regarded
+	    as unsolicited and discarded. DPA now causes the
+	    transport process in question to be terminated, as for
+	    DPR that diameter itself sends.</p>
+          <p>
+	    Own Id: OTP-12542</p>
+        </item>
+        <item>
+          <p>
+	    Discard requests after DPR.</p>
+          <p>
+	    RFC 6733 is imprecise, but the tone is that messages
+	    received after DPR are an exception to be dealt with only
+	    because of the possibility of unordered delivery over
+	    SCTP. As a consequence, and because a request following
+	    DPR is unlikely to be answered due to the impending loss
+	    of the peer connection, discard outgoing requests
+	    following an outgoing or incoming DPR. Incoming requests
+	    are also discarded, with the exception of DPR itself.
+	    Answers are sent and received as usual.</p>
+          <p>
+	    Own Id: OTP-12543</p>
+        </item>
+        <item>
+          <p>
+	    Add transport_opt() dpr_timeout.</p>
+          <p>
+	    To cause a peer connection to be closed following an
+	    outgoing DPA when the peer fails to do so. It is the
+	    recipient of DPA that should close the connection
+	    according to RFC 6733.</p>
+          <p>
+	    Own Id: OTP-12609</p>
+        </item>
+        <item>
+          <p>
+	    Add service_opt() incoming_maxlen.</p>
+          <p>
+	    To bound the expected size of incoming Diameter messages.
+	    Messages larger than the specified number of bytes are
+	    discarded, to prevent a malicious peer from generating
+	    excessive load.</p>
+          <p>
+	    Own Id: OTP-12628</p>
+        </item>
+      </list>
+    </section>
+
+</section>
+
+<section><title>diameter 1.8</title>
+
+    <section><title>Fixed Bugs and Malfunctions</title>
+      <list>
+        <item>
+          <p>
+	    Fix remote diameter_request table leak.</p>
+          <p>
+	    An outgoing request whose pick_peer callback selected a
+	    transport on another node resulted in an orphaned table
+	    entry on that node.</p>
+          <p>
+	    Own Id: OTP-12196</p>
+        </item>
+        <item>
+          <p>
+	    Fix handling of 3xxx Result-Code without E-bit.</p>
+          <p>
+	    OTP-12233 broke the population of the errors field of the
+	    diameter_packet record when an incoming request with an
+	    E-bit/Result-Code mismatch was detected, causing a
+	    4-tuple to be inserted as Result-Code in a diameter_avp
+	    record.</p>
+          <p>
+	    Own Id: OTP-12233</p>
+        </item>
+        <item>
+          <p>
+	    Fix ignored connect timer.</p>
+          <p>
+	    There are two timers governing the establishment of peer
+	    connections: connect_timer and watchdog_timer. The former
+	    is the RFC 6733 Tc timer, and is used at initial
+	    connection establishment. The latter is RFC 3539 TwInit,
+	    and is used for connection reestablishment. A connecting
+	    transport erroneously used watchdog_timer in both cases.</p>
+          <p>
+	    Own Id: OTP-12281 Aux Id: seq12728 </p>
+        </item>
+      </list>
+    </section>
+
+
+    <section><title>Improvements and New Features</title>
+      <list>
+        <item>
+          <p>
+	    Order candidate peers in pick_peer callbacks.</p>
+          <p>
+	    The order of candidate peers presented to a
+	    diameter_app(3) pick_peer callback has previously not
+	    been documented, but there are use cases that are
+	    simplified by an ordering. The order is now determined by
+	    the filter.</p>
+          <p>
+	    Own Id: OTP-12308</p>
+        </item>
+      </list>
+    </section>
+
+</section>
+
+<section><title>diameter 1.7.1</title>
+
+    <section><title>Fixed Bugs and Malfunctions</title>
+      <list>
+        <item>
+          <p>
+	    Don't leave extra bit in decoded AVP data.</p>
+          <p>
+	    An extra bit could be communicated in the data field of a
+	    diameter_avp record in the case of length errors. Of no
+	    consequence for code using the record encoding of
+	    Diameter messages, but code examining diameter_avp
+	    records would see this bit.</p>
+          <p>
+	    Dictionary files must be recompiled for the fix to have
+	    effect.</p>
+          <p>
+	    Own Id: OTP-12074</p>
+        </item>
+        <item>
+          <p>
+	    Fix counting of outgoing requests and answers setting the
+	    E-bit.</p>
+          <p>
+	    OTP-11721 broke these counters for all outgoing requests
+	    except DWR, and caused answers setting the E-bit to be
+	    counted as unknown messages.</p>
+          <p>
+	    Own Id: OTP-12080</p>
+        </item>
+        <item>
+          <p>
+	    Fix Failed-AVP decode.</p>
+          <p>
+	    The best-effort decode only worked for AVPs in the common
+	    dictionary, not for those in the dictionary of the
+	    application identified in the Diameter Header of the
+	    answer message in question.</p>
+          <p>
+	    Failed-AVP in an answer decoded with the RFC 3588 common
+	    dictionary (diameter_gen_base_rfc3588) was regarded as an
+	    error. The RFC 6733 dictionary was unaffected.</p>
+          <p>
+	    Dictionary files must be recompiled for the fix to have
+	    effect.</p>
+          <p>
+	    Own Id: OTP-12094</p>
+        </item>
+      </list>
+    </section>
+
+</section>
+
+<section><title>diameter 1.7</title>
+
+    <section><title>Fixed Bugs and Malfunctions</title>
+      <list>
+        <item>
+          <p>
+	    Improve robustness.</p>
+          <p>
+	    Counters returned by diameter:service_info/2 now only
+	    count messages known to the dictionary in question, so
+	    that an attacker cannot cause arbitrarily many counters
+	    to be created.</p>
+          <p>
+	    Messages to the Erlang log have been minimized, and those
+	    related to traffic have been removed entirely since an
+	    attacker could cause a node to be logged to death.
+	    Consequently, the default answer_errors configuration has
+	    been changed from report to discard. A service needs to
+	    be restarted for the change in default to take effect.</p>
+          <p>
+	    Own Id: OTP-11721</p>
+        </item>
+        <item>
+          <p>
+	    Fix request table leak.</p>
+          <p>
+	    Outgoing Diameter requests are stored in a table until an
+	    answer is received or times out. Calling
+	    diameter:stop_service/1 before this took place would
+	    orphan the entries, resulting in a memory leak.</p>
+          <p>
+	    Own Id: OTP-11893</p>
+        </item>
+        <item>
+          <p>
+	    Fix broken SCTP transport.</p>
+          <p>
+	    OTP-11593 caused the sending of answer messages over SCTP
+	    to fail.</p>
+          <p>
+	    Own Id: OTP-11901 Aux Id: OTP-11593 </p>
+        </item>
+        <item>
+          <p>
+	    Fix watchdog process leak.</p>
+          <p>
+	    A failed capabilities exchange on a listening transport
+	    would orphan a process, causing a memory leak.</p>
+          <p>
+	    Own Id: OTP-11934</p>
+        </item>
+        <item>
+          <p>
+	    Fix incorrect handling of incoming DPR.</p>
+          <p>
+	    In the case of a listening transport, a reconnection by a
+	    peer following DPR could transition the watchdog state to
+	    REOPEN instead of OKAY.</p>
+          <p>
+	    Own Id: OTP-11938</p>
+        </item>
+        <item>
+          <p>
+	    Fix handling of AVP length errors on unknown AVPs.</p>
+          <p>
+	    An AVP (Header) length that pointed past the end of the
+	    message was not flagged as a 5014 error in this case.
+	    Moreover, encoding such an AVP in the Failed-AVP of an
+	    answer message as a consequence of other errors (eg.
+	    M-bit, resulting in 5001) failed if the AVP contained a
+	    complete header.</p>
+          <p>
+	    Dictionary files must be recompiled for the fix to have
+	    effect.</p>
+          <p>
+	    Own Id: OTP-11946</p>
+        </item>
+        <item>
+          <p>
+	    Fix broken check in dictionary compilation.</p>
+          <p>
+	    That an AVP specified in the content of a @codecs or
+	    @custom_types section was undefined went undetected,
+	    causing compilation to fail when attempting to lookup the
+	    AVP's type.</p>
+          <p>
+	    Own Id: OTP-11958</p>
+        </item>
+      </list>
+    </section>
+
+
+    <section><title>Improvements and New Features</title>
+      <list>
+        <item>
+          <p>
+	    Add result code counters for CEA, DWA, and DPA.</p>
+          <p>
+	    In addition to the existing result code counters on other
+	    answer messages.</p>
+          <p>
+	    Own Id: OTP-11891</p>
+        </item>
+        <item>
+          <p>
+	    Add best-effort decode of AVPs within Failed-AVP.</p>
+          <p>
+	    OTP-11007 disabled the decode of AVPs in Failed-AVP since
+	    errors could cause the decode of Failed-AVP itself to
+	    fail. Component AVPs are now decoded if possible,
+	    otherwise not. AVPs of type Grouped are decoded as much
+	    as possible, as deeply as possible.</p>
+          <p>
+	    Dictionary files must be recompiled for the fix to have
+	    effect.</p>
+          <p>
+	    Own Id: OTP-11936 Aux Id: OTP-11007 </p>
+        </item>
+        <item>
+          <p>
+	    Add counters for encode errors in outgoing Diameter
+	    messages.</p>
+          <p>
+	    In addition to the existing counters on decode errors.
+	    The latter now count independently of result codes in
+	    answer messages since decode errors do not preclude the
+	    presence of a result code.</p>
+          <p>
+	    Own Id: OTP-11937</p>
+        </item>
+      </list>
+    </section>
+
+</section>
+
+<section><title>diameter 1.6</title>
+
+    <section><title>Fixed Bugs and Malfunctions</title>
+      <list>
+        <item>
+          <p>
+	    Add missing check at dictionary compilation.</p>
+          <p>
+	    In particular, that an AVP defined as having type Grouped
+	    in an @avp_types section has a corresponding definition
+	    in a @grouped section.</p>
+          <p>
+	    Own Id: OTP-11561</p>
+        </item>
+        <item>
+          <p>
+	    Correct documentation on the setting of Origin-State-Id</p>
+          <p>
+	    It was incorrectly stated that the AVP would be set in an
+	    outgoing DPR/DPA.</p>
+          <p>
+	    Own Id: OTP-11583</p>
+        </item>
+        <item>
+          <p>
+	    Change interface for communicating outbound stream id to
+	    diameter_sctp</p>
+          <p>
+	    The module uses the transport_data field of record
+	    diameter_packet to communicate the stream on which the an
+	    incoming message is received and on which an outgoing
+	    message should be sent, the previous interface being that
+	    both are communicated as a tuple of the form {stream,
+	    Id}. However, since diameter retains the value of an
+	    incoming request's transport_data unless the
+	    corresponding answer message specifies otherwise, the
+	    behaviour in this case is to send an answer on the
+	    outbound stream with the same identifier as the that of
+	    the inbound stream on which the request was received. If
+	    the inbound stream id is greater than or equal to the
+	    number of outbound streams then this is guaranteed to
+	    fail, causing the transport process in question to
+	    terminate. There is no relationship between inbound and
+	    outbound stream identifiers so diameter_sctp's imposition
+	    of one is simply wrong.</p>
+          <p>
+	    Outbound stream ids are now communicated with a different
+	    tuple: {outstream, Id}, interpreted modulo the number of
+	    outbound streams. Thus, retention of an inbound request's
+	    transport_data has no effect on the selection of an
+	    outbound stream.</p>
+          <p>
+	    The change in interface is not strictly backwards
+	    compatible because of the new atom for the outbound
+	    stream. However, as there is currently no documented way
+	    of obtaining the available number of outbound streams for
+	    a peer connection, there is no way for a client to have
+	    known the range of ids from which it could reliably have
+	    chosen with the previous interface, so any setting of the
+	    outbound stream has probably been unintentional. Not
+	    explicitly specifying an outbound stream now results in a
+	    round-robin selection.</p>
+          <p>
+	    Thanks to Sharmila Pillai for reporting the problem.</p>
+          <p>
+	    *** POTENTIAL INCOMPATIBILITY ***</p>
+          <p>
+	    Own Id: OTP-11593</p>
+        </item>
+        <item>
+          <p>
+	    Fix unicode path failure in diameter_make:codec/2.</p>
+          <p>
+	    A dictionary path containing a unicode codepoint > 255
+	    caused the function to fail.</p>
+          <p>
+	    Own Id: OTP-11655</p>
+        </item>
+        <item>
+          <p>
+	    Fix 'accept' config to diameter_sctp.</p>
+          <p>
+	    OTP-10893 added support for {accept, Match} tuples to
+	    specify addresses or regexps that should be matched
+	    against peer addresses to decide whether or not a newly
+	    established association should be retained, but this
+	    hasn't been functional in the SCTP case because of
+	    missing support in inet(3).</p>
+          <p>
+	    The display of both local and peer addresses in
+	    diameter:service_info/2 output has also been corrected.</p>
+          <p>
+	    Own Id: OTP-11661 Aux Id: OTP-10229 </p>
+        </item>
+        <item>
+          <p>
+	    Be lenient with the M-bit in Grouped AVPs.</p>
+          <p>
+	    RFC 6733 says this, in 4.4:</p>
+          <p>
+	    <taglist><item><p><c>Receivers of a Grouped AVP that does
+	    not have the 'M' (mandatory) bit set and one or more of
+	    the encapsulated AVPs within the group has the 'M'
+	    (mandatory) bit set MAY simply be ignored if the Grouped
+	    AVP itself is unrecognized. The rule applies even if the
+	    encapsulated AVP with its 'M' (mandatory) bit set is
+	    further encapsulated within other sub-groups, i.e., other
+	    Grouped AVPs embedded within the Grouped
+	    AVP.</c></p></item></taglist></p>
+          <p>
+	    The first sentence is mangled but take it to mean this:</p>
+          <p>
+	    <taglist><item><p><c>An unrecognized AVP of type Grouped
+	    that does not set the 'M' bit MAY be ignored even if one
+	    of its encapsulated AVPs sets the 'M'
+	    bit.</c></p></item></taglist></p>
+          <p>
+	    This is a bit of a non-statement since if the AVP is
+	    unrecognized then its type is unknown. We therefore don't
+	    know that its data bytes contain encapsulated AVPs, so
+	    can't but ignore any of those that set the M-bit. Doing
+	    anything else when the type *is* known would be
+	    inconsistent.</p>
+          <p>
+	    OTP-11087 (R16B03) caused the M-bit on any unrecognized
+	    AVP to be regarded as an error, unrecognized being taken
+	    to mean "not explicitly defined as a member of its
+	    container". (That is, an AVP that can't be packed into a
+	    dedicated record field, which is slightly stronger than
+	    "not defined".) This fixed the original intention for
+	    top-level AVPs but broke the required leniency for
+	    Grouped AVPs whose type is known. This leniency is now
+	    restored.</p>
+          <p>
+	    Note that dictionary files need to be recompiled for the
+	    change to have effect.</p>
+          <p>
+	    Thanks to Rory McKeown for reporting the problem.</p>
+          <p>
+	    Own Id: OTP-11675 Aux Id: OTP-11087 </p>
+        </item>
+        <item>
+          <p>
+	    Fix pick_peer case clause failure.</p>
+          <p>
+	    In the case of {call_mutates_state, true} configuration
+	    on the service in question, any peer selection that
+	    failed to select a peer resulted in a case clause
+	    failure. This was noticed in the case of a peer failover
+	    in which an alternate peer wasn't available.</p>
+          <p>
+	    Own Id: OTP-11789</p>
+        </item>
+      </list>
+    </section>
+
+</section>
+
+<section><title>diameter 1.5</title>
+
+    <section><title>Improvements and New Features</title>
+      <list>
+        <item>
+          <p>
+	    Rename reconnect_timer to connect_timer.</p>
+          <p>
+	    The former is still accepted for backwards compatibility,
+	    but the name is misleading given the semantics of the
+	    timer.</p>
+          <p>
+	    Own Id: OTP-11168</p>
+        </item>
+        <item>
+          <p>
+	    Extend diameter_make(3).</p>
+          <p>
+	    Dictionaries can now be compiled from strings, not just
+	    filesystem paths, and results can be returned instead of
+	    written to the filesystem.</p>
+          <p>
+	    Own Id: OTP-11348</p>
+        </item>
+        <item>
+          <p>
+	    Remove hardcoding of diameter_base as @prefix on
+	    dictionaries for application id 0.</p>
+          <p>
+	    Own Id: OTP-11361</p>
+        </item>
+      </list>
+    </section>
+
+</section>
+
+<section><title>diameter 1.4.4</title>
+
+    <section><title>Fixed Bugs and Malfunctions</title>
+      <list>
+        <item>
+          <p>
+	    Fix setting of End-to-End and Hop-by-Hop Identifiers in
+	    outgoing DWA.</p>
+          <p>
+	    Broken by OTP-11184, which caused the identifiers to be
+	    set anew, discarding the values from the incoming DWR.</p>
+          <p>
+	    Own Id: OTP-11367</p>
+        </item>
+        <item>
+          <p>
+	    Fix handling of 5014, DIAMETER_INVALID_AVP_LENGTH.</p>
+          <p>
+	    The error was detected as 5004,
+	    DIAMETER_INVALID_AVP_VALUE, for some Diameter types, in
+	    which case an AVP length that pointed past the end of a
+	    message resulted in encode failure.</p>
+          <p>
+	    Own Id: OTP-11395</p>
+        </item>
+      </list>
+    </section>
+
+</section>
+
+<section><title>diameter 1.4.3</title>
+
+    <section><title>Fixed Bugs and Malfunctions</title>
+      <list>
+        <item>
+          <p>
+	    Fix UTF8String encode.</p>
+          <p>
+	    Encode now accepts any nested list of codepoints and
+	    binaries. A list containing a binary was previously
+	    misinterpreted and the documentation was incomplete.</p>
+          <p>
+	    Own Id: OTP-11172</p>
+        </item>
+        <item>
+          <p>
+	    Ensure DWR isn't sent immediately after DWA.</p>
+          <p>
+	    This was possible if the timing was unfortunate. An
+	    incoming DWR now properly resets the watchdog timer.</p>
+          <p>
+	    Own Id: OTP-11184</p>
+        </item>
+        <item>
+          <p>
+	    Fix faulty encode of Failed-AVP</p>
+          <p>
+	    Reception of a CER, DWR or DPR that has decode failures
+	    caused encode of the corresponding answer message to
+	    fail.</p>
+          <p>
+	    Own Id: OTP-11293</p>
+        </item>
+        <item>
+          <p>
+	    Fix broken service_opt() spawn_opt.</p>
+          <p>
+	    The option was ignored.</p>
+          <p>
+	    Own Id: OTP-11299</p>
+        </item>
+      </list>
+    </section>
+
+</section>
+
 <section><title>diameter 1.4.2</title>
 
     <section><title>Fixed Bugs and Malfunctions</title>
diff --git a/lib/diameter/doc/src/ref_man.xml b/lib/diameter/doc/src/ref_man.xml
index 4b99fe716d..a0ef28844d 100644
--- a/lib/diameter/doc/src/ref_man.xml
+++ b/lib/diameter/doc/src/ref_man.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="latin1" ?>
+<?xml version="1.0" encoding="utf-8" ?>
 <!DOCTYPE application SYSTEM "application.dtd">
 
 <application xmlns:xi="http://www.w3.org/2001/XInclude">
@@ -6,20 +6,21 @@
 <header>
 <copyright>
 <year>2011</year>
-<year>2012</year>
+<year>2016</year>
 <holder>Ericsson AB. All Rights Reserved.</holder>
 </copyright>
 <legalnotice>
-The contents of this file are subject to the Erlang Public License,
-Version 1.1, (the "License"); you may not use this file except in
-compliance with the License. You should have received a copy of the
-Erlang Public License along with this software. If not, it can be
-retrieved online at http://www.erlang.org/.
-
-Software distributed under the License is distributed on an "AS IS"
-basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-the License for the specific language governing rights and limitations
-under the License.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+ 
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
 
 </legalnotice>
 
@@ -39,7 +40,7 @@ applications on top of the Diameter protocol. </p>
 </description>
 
 <xi:include href="diameter.xml"/>
-<xi:include href="diameter_compile.xml"/>
+<xi:include href="diameterc.xml"/>
 <xi:include href="diameter_app.xml"/>
 <xi:include href="diameter_codec.xml"/>
 <xi:include href="diameter_dict.xml"/>
diff --git a/lib/diameter/doc/src/seealso.ent b/lib/diameter/doc/src/seealso.ent
index 76b9823f79..e5c284c6e8 100644
--- a/lib/diameter/doc/src/seealso.ent
+++ b/lib/diameter/doc/src/seealso.ent
@@ -4,18 +4,19 @@
 
 %CopyrightBegin%
 
-Copyright Ericsson AB 2012-2013. All Rights Reserved.
+Copyright Ericsson AB 2012-2015. All Rights Reserved.
 
-The contents of this file are subject to the Erlang Public License,
-Version 1.1, (the "License"); you may not use this file except in
-compliance with the License. You should have received a copy of the
-Erlang Public License along with this software. If not, it can be
-retrieved online at http://www.erlang.org/.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+ 
+    http://www.apache.org/licenses/LICENSE-2.0
 
-Software distributed under the License is distributed on an "AS IS"
-basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-the License for the specific language governing rights and limitations
-under the License.
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
 
 %CopyrightEnd%
 
@@ -64,11 +65,14 @@ significant.
 <!ENTITY capabilities_cb '<seealso marker="#capabilities_cb">capabilities_cb</seealso>'>
 <!ENTITY capx_timeout '<seealso marker="#capx_timeout">capx_timeout</seealso>'>
 <!ENTITY disconnect_cb '<seealso marker="#disconnect_cb">disconnect_cb</seealso>'>
+<!ENTITY dpa_timeout '<seealso marker="#dpa_timeout">dpa_timeout</seealso>'>
 <!ENTITY transport_config '<seealso marker="#transport_config">transport_config</seealso>'>
 <!ENTITY transport_module '<seealso marker="#transport_module">transport_module</seealso>'>
-<!ENTITY reconnect_timer '<seealso marker="#reconnect_timer">reconnect_timer</seealso>'>
+<!ENTITY connect_timer '<seealso marker="#connect_timer">connect_timer</seealso>'>
 <!ENTITY watchdog_timer '<seealso marker="#watchdog_timer">watchdog_timer</seealso>'>
 
+<!ENTITY mod_string_decode '<seealso marker="diameter#service_opt">diameter:service_opt()</seealso> <seealso marker="diameter#string_decode">string_decode</seealso>'>
+
 <!-- diameter_app -->
 
 <!ENTITY app_handle_answer '<seealso marker="diameter_app#Mod:handle_answer-4">handle_answer/4</seealso>'>
@@ -102,6 +106,9 @@ significant.
 
 <!ENTITY dict_Address '<seealso marker="diameter_dict#DATA_TYPES">Address()</seealso>'>
 <!ENTITY dict_DiameterIdentity '<seealso marker="diameter_dict#DATA_TYPES">DiameterIdentity()</seealso>'>
+<!ENTITY dict_DiameterURI '<seealso marker="diameter_dict#DATA_TYPES">DiameterURI()</seealso>'>
+<!ENTITY dict_IPFilterRule '<seealso marker="diameter_dict#DATA_TYPES">IPFilterRule()</seealso>'>
+<!ENTITY dict_QoSFilterRule '<seealso marker="diameter_dict#DATA_TYPES">QoSFilterRule()</seealso>'>
 <!ENTITY dict_Grouped '<seealso marker="diameter_dict#DATA_TYPES">Grouped()</seealso>'>
 <!ENTITY dict_OctetString '<seealso marker="diameter_dict#DATA_TYPES">OctetString()</seealso>'>
 <!ENTITY dict_Time '<seealso marker="diameter_dict#DATA_TYPES">Time()</seealso>'>
@@ -115,6 +122,9 @@ significant.
 <!-- diameter_make -->
 
 <!ENTITY make_codec '<seealso marker="diameter_make#codec-2">diameter_make:codec/2</seealso>'>
+<!ENTITY make_format '<seealso marker="diameter_make#format-1">diameter_make:format/1</seealso>'>
+<!ENTITY make_flatten '<seealso marker="diameter_make#flatten-1">diameter_make:flatten/1</seealso>'>
+<!ENTITY make_format_error '<seealso marker="diameter_make#format_error-1">diameter_make:format_error/1</seealso>'>
 
 <!-- diameter_transport -->
 
diff --git a/lib/diameter/doc/src/seehere.sed b/lib/diameter/doc/src/seehere.sed
index c62a783d40..10eca9258e 100644
--- a/lib/diameter/doc/src/seehere.sed
+++ b/lib/diameter/doc/src/seehere.sed
@@ -1,18 +1,19 @@
 #
 # %CopyrightBegin%
 #
-# Copyright Ericsson AB 2012. All Rights Reserved.
-#
-# The contents of this file are subject to the Erlang Public License,
-# Version 1.1, (the "License"); you may not use this file except in
-# compliance with the License. You should have received a copy of the
-# Erlang Public License along with this software. If not, it can be
-# retrieved online at http://www.erlang.org/.
-#
-# Software distributed under the License is distributed on an "AS IS"
-# basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-# the License for the specific language governing rights and limitations
-# under the License.
+# Copyright Ericsson AB 2012-2016. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
 #
 # %CopyrightEnd%
 
diff --git a/lib/diameter/doc/src/user_man.xml b/lib/diameter/doc/src/user_man.xml
index a6416c7e23..adfc8de880 100644
--- a/lib/diameter/doc/src/user_man.xml
+++ b/lib/diameter/doc/src/user_man.xml
@@ -1,24 +1,25 @@
-<?xml version="1.0" encoding="latin1" ?>
+<?xml version="1.0" encoding="utf-8" ?>
 <!DOCTYPE part SYSTEM "part.dtd">
 
 <part xmlns:xi="http://www.w3.org/2001/XInclude">
 
 <header>
 <copyright>
-<year>2011</year>
+<year>2011</year><year>2016</year>
 <holder>Ericsson AB. All Rights Reserved.</holder>
 </copyright>
 <legalnotice>
-The contents of this file are subject to the Erlang Public License,
-Version 1.1, (the "License"); you may not use this file except in
-compliance with the License. You should have received a copy of the
-Erlang Public License along with this software. If not, it can be
-retrieved online at http://www.erlang.org/.
-
-Software distributed under the License is distributed on an "AS IS"
-basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
-the License for the specific language governing rights and limitations
-under the License.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+ 
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
 
 </legalnotice>
 
diff --git a/lib/diameter/doc/standard/rfc7068.txt b/lib/diameter/doc/standard/rfc7068.txt
new file mode 100644
index 0000000000..70fc24fab0
--- /dev/null
+++ b/lib/diameter/doc/standard/rfc7068.txt
@@ -0,0 +1,1627 @@
+
+
+
+
+
+
+Internet Engineering Task Force (IETF)                        E. McMurry
+Request for Comments: 7068                                   B. Campbell
+Category: Informational                                           Oracle
+ISSN: 2070-1721                                            November 2013
+
+
+                 Diameter Overload Control Requirements
+
+Abstract
+
+   When a Diameter server or agent becomes overloaded, it needs to be
+   able to gracefully reduce its load, typically by advising clients to
+   reduce traffic for some period of time.  Otherwise, it must continue
+   to expend resources parsing and responding to Diameter messages,
+   possibly resulting in a progressively severe overload condition.  The
+   existing Diameter mechanisms are not sufficient for managing overload
+   conditions.  This document describes the limitations of the existing
+   mechanisms.  Requirements for new overload management mechanisms are
+   also provided.
+
+Status of This Memo
+
+   This document is not an Internet Standards Track specification; it is
+   published for informational purposes.
+
+   This document is a product of the Internet Engineering Task Force
+   (IETF).  It represents the consensus of the IETF community.  It has
+   received public review and has been approved for publication by the
+   Internet Engineering Steering Group (IESG).  Not all documents
+   approved by the IESG are a candidate for any level of Internet
+   Standard; see Section 2 of RFC 5741.
+
+   Information about the current status of this document, any errata,
+   and how to provide feedback on it may be obtained at
+   http://www.rfc-editor.org/info/rfc7068.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+McMurry & Campbell            Informational                     [Page 1]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+Copyright Notice
+
+   Copyright (c) 2013 IETF Trust and the persons identified as the
+   document authors.  All rights reserved.
+
+   This document is subject to BCP 78 and the IETF Trust's Legal
+   Provisions Relating to IETF Documents
+   (http://trustee.ietf.org/license-info) in effect on the date of
+   publication of this document.  Please review these documents
+   carefully, as they describe your rights and restrictions with respect
+   to this document.  Code Components extracted from this document must
+   include Simplified BSD License text as described in Section 4.e of
+   the Trust Legal Provisions and are provided without warranty as
+   described in the Simplified BSD License.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+McMurry & Campbell            Informational                     [Page 2]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+Table of Contents
+
+   1. Introduction ....................................................4
+      1.1. Documentation Conventions ..................................4
+      1.2. Causes of Overload .........................................5
+      1.3. Effects of Overload ........................................6
+      1.4. Overload vs. Network Congestion ............................6
+      1.5. Diameter Applications in a Broader Network .................7
+   2. Overload Control Scenarios ......................................7
+      2.1. Peer-to-Peer Scenarios .....................................8
+      2.2. Agent Scenarios ...........................................10
+      2.3. Interconnect Scenario .....................................14
+   3. Diameter Overload Case Studies .................................15
+      3.1. Overload in Mobile Data Networks ..........................15
+      3.2. 3GPP Study on Core Network Overload .......................16
+   4. Existing Mechanisms ............................................17
+   5. Issues with the Current Mechanisms .............................18
+      5.1. Problems with Implicit Mechanism ..........................18
+      5.2. Problems with Explicit Mechanisms .........................18
+   6. Extensibility and Application Independence .....................19
+   7. Solution Requirements ..........................................20
+      7.1. General ...................................................20
+      7.2. Performance ...............................................21
+      7.3. Heterogeneous Support for Solution ........................22
+      7.4. Granular Control ..........................................23
+      7.5. Priority and Policy .......................................23
+      7.6. Security ..................................................23
+      7.7. Flexibility and Extensibility .............................24
+   8. Security Considerations ........................................25
+      8.1. Access Control ............................................25
+      8.2. Denial-of-Service Attacks .................................26
+      8.3. Replay Attacks ............................................26
+      8.4. Man-in-the-Middle Attacks .................................26
+      8.5. Compromised Hosts .........................................27
+   9. References .....................................................27
+      9.1. Normative References ......................................27
+      9.2. Informative References ....................................27
+   Appendix A. Contributors ..........................................29
+   Appendix B. Acknowledgements ......................................29
+
+
+
+
+
+
+
+
+
+
+
+
+McMurry & Campbell            Informational                     [Page 3]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+1.  Introduction
+
+   A Diameter [RFC6733] node is said to be overloaded when it has
+   insufficient resources to successfully process all of the Diameter
+   requests that it receives.  When a node becomes overloaded, it needs
+   to be able to gracefully reduce its load, typically by advising
+   clients to reduce traffic for some period of time.  Otherwise, it
+   must continue to expend resources parsing and responding to Diameter
+   messages, possibly resulting in a progressively severe overload
+   condition.  The existing mechanisms provided by Diameter are not
+   sufficient for managing overload conditions.  This document describes
+   the limitations of the existing mechanisms and provides requirements
+   for new overload management mechanisms.
+
+   This document draws on the work done on SIP overload control
+   ([RFC5390], [RFC6357]) as well as on experience gained via overload
+   handling in Signaling System No. 7 (SS7) networks and studies done by
+   the Third Generation Partnership Project (3GPP) (Section 3).
+
+   Diameter is not typically an end-user protocol; rather, it is
+   generally used as one component in support of some end-user activity.
+
+   For example, a SIP server might use Diameter to authenticate and
+   authorize user access.  Overload in the Diameter backend
+   infrastructure will likely impact the experience observed by the end
+   user in the SIP application.
+
+   The impact of Diameter overload on the client application (a client
+   application may use the Diameter protocol and other protocols to do
+   its job) is beyond the scope of this document.
+
+   This document presents non-normative descriptions of causes of
+   overload, along with related scenarios and studies.  Finally, it
+   offers a set of normative requirements for an improved overload
+   indication mechanism.
+
+1.1.  Documentation Conventions
+
+   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
+   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
+   document are to be interpreted as defined in [RFC2119], with the
+   exception that they are not intended for interoperability of
+   implementations.  Rather, they are used to describe requirements
+   towards future specifications where the interoperability requirements
+   will be defined.
+
+   The terms "client", "server", "agent", "node", "peer", "upstream",
+   and "downstream" are used as defined in [RFC6733].
+
+
+
+McMurry & Campbell            Informational                     [Page 4]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+1.2.  Causes of Overload
+
+   Overload occurs when an element, such as a Diameter server or agent,
+   has insufficient resources to successfully process all of the traffic
+   it is receiving.  Resources include all of the capabilities of the
+   element used to process a request, including CPU processing, memory,
+   I/O, and disk resources.  It can also include external resources such
+   as a database or DNS server, in which case the CPU, processing,
+   memory, I/O, and disk resources of those elements are effectively
+   part of the logical element processing the request.
+
+   External resources can include upstream Diameter nodes; for example,
+   a Diameter agent can become effectively overloaded if one or more
+   upstream nodes are overloaded.
+
+   A Diameter node can become overloaded due to request levels that
+   exceed its capacity, a reduction of available resources (for example,
+   a local or upstream hardware failure), or a combination of the two.
+
+   Overload can occur for many reasons, including:
+
+   Inadequate capacity:  When designing Diameter networks, that is,
+      application-layer multi-node Diameter deployments, it can be very
+      difficult to predict all scenarios that may cause elevated
+      traffic.  It may also be more costly to implement support for some
+      scenarios than a network operator may deem worthwhile.  This
+      results in the likelihood that a Diameter network will not have
+      adequate capacity to handle all situations.
+
+   Dependency failures:  A Diameter node can become overloaded because a
+      resource on which it depends has failed or become overloaded,
+      greatly reducing the logical capacity of the node.  In these
+      cases, even minimal traffic might cause the node to go into
+      overload.  Examples of such dependency overloads include DNS
+      servers, databases, disks, and network interfaces that have failed
+      or become overloaded.
+
+   Component failures:  A Diameter node can become overloaded when it is
+      a member of a cluster of servers that each share the load of
+      traffic and one or more of the other members in the cluster fail.
+      In this case, the remaining nodes take over the work of the failed
+      nodes.  Normally, capacity planning takes such failures into
+      account, and servers are typically run with enough spare capacity
+      to handle failure of another node.  However, unusual failure
+      conditions can cause many nodes to fail at once.  This is often
+      the case with software failures, where a bad packet or bad
+      database entry hits the same bug in a set of nodes in a cluster.
+
+
+
+
+McMurry & Campbell            Informational                     [Page 5]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+   Network-initiated traffic flood:  Certain access network events can
+      precipitate floods of Diameter signaling traffic.  For example,
+      operational changes can trigger avalanche restarts, or frequent
+      radio overlay handovers can generate excessive authorization
+      requests.  Failure of a Diameter proxy may also result in a large
+      amount of signaling as connections and sessions are reestablished.
+
+   Subscriber-initiated traffic flood:  Large gatherings of subscribers
+      or events that result in many subscribers interacting with the
+      network in close time proximity can result in Diameter signaling
+      traffic floods.  For example, the finale of a large fireworks show
+      could be immediately followed by many subscribers posting
+      messages, pictures, and videos concentrated on one portion of a
+      network.  Subscriber devices such as smartphones may use
+      aggressive registration strategies that generate unusually high
+      Diameter traffic loads.
+
+   DoS attacks:  An attacker wishing to disrupt service in the network
+      can cause a large amount of traffic to be launched at a target
+      element.  This can be done from a central source of traffic or
+      through a distributed DoS attack.  In all cases, the volume of
+      traffic well exceeds the capacity of the element, sending the
+      system into overload.
+
+1.3.  Effects of Overload
+
+   Modern Diameter networks, composed of application-layer multi-node
+   deployments of Diameter elements, may operate at very large
+   transaction volumes.  If a Diameter node becomes overloaded or, even
+   worse, fails completely, a large number of messages may be lost very
+   quickly.  Even with redundant servers, many messages can be lost in
+   the time it takes for failover to complete.  While a Diameter client
+   or agent should be able to retry such requests, an overloaded peer
+   may cause a sudden large increase in the number of transactions
+   needing to be retried, rapidly filling local queues or otherwise
+   contributing to local overload.  Therefore, Diameter devices need to
+   be able to shed load before critical failures can occur.
+
+1.4.  Overload vs. Network Congestion
+
+   This document uses the term "overload" to refer to application-layer
+   overload at Diameter nodes.  This is distinct from "network
+   congestion", that is, congestion that occurs at the lower networking
+   layers that may impact the delivery of Diameter messages between
+   nodes.  This document recognizes that element overload and network
+   congestion are interrelated, and that overload can contribute to
+   network congestion and vice versa.
+
+
+
+
+McMurry & Campbell            Informational                     [Page 6]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+   Network congestion issues are better handled by the transport
+   protocols.  Diameter uses TCP and the Stream Control Transmission
+   Protocol (SCTP), both of which include congestion management
+   features.  Analysis of whether those features are sufficient for
+   transport-level congestion between Diameter nodes and of any work to
+   further mitigate network congestion is out of scope for both this
+   document and the work proposed by it.
+
+1.5.  Diameter Applications in a Broader Network
+
+   Most elements using Diameter applications do not use Diameter
+   exclusively.  It is important to realize that overload of an element
+   can be caused by a number of factors that may be unrelated to the
+   processing of Diameter or Diameter applications.
+
+   An element that doesn't use Diameter exclusively needs to be able to
+   signal to Diameter peers that it is experiencing overload regardless
+   of the cause of the overload, since the overload will affect that
+   element's ability to process Diameter transactions.  If the element
+   communicates with protocols other than Diameter, it may also need to
+   signal the overload situation on these protocols, depending on its
+   function and the architecture of the network and application for
+   which it is providing services.  Whether that is necessary can only
+   be decided within the context of that architecture and use cases.
+   This specification details the requirements for a mechanism for
+   signaling overload with Diameter; this mechanism provides Diameter
+   nodes the ability to inform their Diameter peers of overload,
+   mitigating that part of the issue.  Diameter nodes may need to use
+   this, as well as other mechanisms, to solve their broader overload
+   issues.  Indicating overload on protocols other than Diameter is out
+   of scope for this document and for the work proposed by it.
+
+2.  Overload Control Scenarios
+
+   Several Diameter deployment scenarios exist that may impact overload
+   management.  The following scenarios help motivate the requirements
+   for an overload management mechanism.
+
+   These scenarios are by no means exhaustive and are in general
+   simplified for the sake of clarity.  In particular, this document
+   assumes for the sake of clarity that the client sends Diameter
+   requests to the server, and the server sends responses to the client,
+   even though Diameter supports bidirectional applications.  Each
+   direction in such an application can be modeled separately.
+
+   In a large-scale deployment, many of the nodes represented in these
+   scenarios would be deployed as clusters of servers.  This document
+   assumes that such a cluster is responsible for managing its own
+
+
+
+McMurry & Campbell            Informational                     [Page 7]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+   internal load-balancing and overload management so that it appears as
+   a single Diameter node.  That is, other Diameter nodes can treat it
+   as a single, monolithic node for the purposes of overload management.
+
+   These scenarios do not illustrate the client application.  As
+   mentioned in Section 1, Diameter is not typically an end-user
+   protocol; rather, it is generally used in support of some other
+   client application.  These scenarios do not consider the impact of
+   Diameter overload on the client application.
+
+2.1.  Peer-to-Peer Scenarios
+
+   This section describes Diameter peer-to-peer scenarios, that is,
+   scenarios where a Diameter client talks directly with a Diameter
+   server, without the use of a Diameter agent.
+
+   Figure 1 illustrates the simplest possible Diameter relationship.
+   The client and server share a one-to-one peer-to-peer relationship.
+   If the server becomes overloaded, either because the client exceeds
+   the server's capacity or because the server's capacity is reduced due
+   to some resource dependency, the client needs to reduce the amount of
+   Diameter traffic it sends to the server.  Since the client cannot
+   forward requests to another server, it must either queue requests
+   until the server recovers or itself become overloaded in the context
+   of the client application and other protocols it may also use.
+
+                            +------------------+
+                            |                  |
+                            |                  |
+                            |     Server       |
+                            |                  |
+                            +--------+---------+
+                                     |
+                                     |
+                            +--------+---------+
+                            |                  |
+                            |                  |
+                            |     Client       |
+                            |                  |
+                            +------------------+
+
+                   Figure 1: Basic Peer-to-Peer Scenario
+
+
+
+
+
+
+
+
+
+McMurry & Campbell            Informational                     [Page 8]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+   Figure 2 shows a similar scenario, except in this case the client has
+   multiple servers that can handle work for a specific realm and
+   application.  If Server 1 becomes overloaded, the client can forward
+   traffic to Server 2.  Assuming that Server 2 has sufficient reserve
+   capacity to handle the forwarded traffic, the client should be able
+   to continue serving client application protocol users.  If Server 1
+   is approaching overload, but can still handle some number of new
+   requests, it needs to be able to instruct the client to forward a
+   subset of its traffic to Server 2.
+
+               +------------------+     +------------------+
+               |                  |     |                  |
+               |                  |     |                  |
+               |     Server 1     |     |     Server 2     |
+               |                  |     |                  |
+               +--------+-`.------+     +------.'+---------+
+                            `.               .'
+                              `.           .'
+                                `.       .'
+                                  `.   .'
+                            +-------`.'--------+
+                            |                  |
+                            |                  |
+                            |     Client       |
+                            |                  |
+                            +------------------+
+
+              Figure 2: Multiple-Server Peer-to-Peer Scenario
+
+   Figure 3 illustrates a peer-to-peer scenario with multiple Diameter
+   realm and application combinations.  In this example, Server 2 can
+   handle work for both applications.  Each application might have
+   different resource dependencies.  For example, a server might need to
+   access one database for Application A and another for Application B.
+   This creates a possibility that Server 2 could become overloaded for
+   Application A but not for Application B, in which case the client
+   would need to divert some part of its Application A requests to
+   Server 1, but the client should not divert any Application B
+   requests.  This requires that Server 2 be able to distinguish between
+   applications when it indicates an overload condition to the client.
+
+   On the other hand, it's possible that the servers host many
+   applications.  If Server 2 becomes overloaded for all applications,
+   it would be undesirable for it to have to notify the client
+   separately for each application.  Therefore, it also needs a way to
+   indicate that it is overloaded for all possible applications.
+
+
+
+
+
+McMurry & Campbell            Informational                     [Page 9]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+   +---------------------------------------------+
+   | Application A       +----------------------+----------------------+
+   |+------------------+ |  +----------------+  |  +------------------+|
+   ||                  | |  |                |  |  |                  ||
+   ||                  | |  |                |  |  |                  ||
+   ||     Server 1     | |  |    Server 2    |  |  |     Server 3     ||
+   ||                  | |  |                |  |  |                  ||
+   |+--------+---------+ |  +-------+--------+  |  +-+----------------+|
+   |         |           |          |           |    |                 |
+   +---------+-----------+----------+-----------+    |                 |
+             |           |          |                |                 |
+             |           |          |                |  Application B  |
+             |           +----------+----------------+-----------------+
+             ``-.._                 |                |
+                   `-..__           |            _.-''
+                        `--._       |        _.-''
+                             ``-._  |   _.-''
+                            +-----`-.-''-----+
+                            |                |
+                            |                |
+                            |     Client     |
+                            |                |
+                            +----------------+
+
+           Figure 3: Multiple-Application Peer-to-Peer Scenario
+
+2.2.  Agent Scenarios
+
+   This section describes scenarios that include a Diameter agent, in
+   the form of either a Diameter relay or Diameter proxy.  These
+   scenarios do not consider Diameter redirect agents, since they are
+   more readily modeled as end servers.  The examples have been kept
+   simple deliberately, to illustrate basic concepts.  Significantly
+   more complicated topologies are possible with Diameter, including
+   multiple intermediate agents in a path connected in a variety
+   of ways.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+McMurry & Campbell            Informational                    [Page 10]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+   Figure 4 illustrates a simple Diameter agent scenario with a single
+   client, agent, and server.  In this case, overload can occur at the
+   server, at the agent, or both.  But in most cases, client behavior is
+   the same whether overload occurs at the server or at the agent.  From
+   the client's perspective, server overload and agent overload are the
+   same thing.
+
+                           +------------------+
+                           |                  |
+                           |                  |
+                           |     Server       |
+                           |                  |
+                           +--------+---------+
+                                    |
+                                    |
+                           +--------+---------+
+                           |                  |
+                           |                  |
+                           |      Agent       |
+                           |                  |
+                           +--------+---------+
+                                    |
+                                    |
+                           +--------+---------+
+                           |                  |
+                           |                  |
+                           |     Client       |
+                           |                  |
+                           +------------------+
+
+                      Figure 4: Basic Agent Scenario
+
+   Figure 5 shows an agent scenario with multiple servers.  If Server 1
+   becomes overloaded but Server 2 has sufficient reserve capacity, the
+   agent may be able to transparently divert some or all Diameter
+   requests originally bound for Server 1 to Server 2.
+
+   In most cases, the client does not have detailed knowledge of the
+   Diameter topology upstream of the agent.  If the agent uses dynamic
+   discovery to find eligible servers, the set of eligible servers may
+   not be enumerable from the perspective of the client.  Therefore, in
+   most cases the agent needs to deal with any upstream overload issues
+   in a way that is transparent to the client.  If one server notifies
+   the agent that it has become overloaded, the notification should not
+   be passed back to the client in a way that the client could
+   mistakenly perceive the agent itself as being overloaded.  If the set
+
+
+
+
+
+McMurry & Campbell            Informational                    [Page 11]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+   of all possible destinations upstream of the agent no longer has
+   sufficient capacity for incoming load, the agent itself becomes
+   effectively overloaded.
+
+   On the other hand, there are cases where the client needs to be able
+   to select a particular server from behind an agent.  For example, if
+   a Diameter request is part of a multiple-round-trip authentication,
+   or is otherwise part of a Diameter "session", it may have a
+   Destination-Host Attribute-Value Pair (AVP) that requires that the
+   request be served by Server 1.  Therefore, the agent may need to
+   inform a client that a particular upstream server is overloaded or
+   otherwise unavailable.  Note that there can be many ways a server can
+   be specified, which may have different implications (e.g., by IP
+   address, by host name, etc).
+
+              +------------------+     +------------------+
+              |                  |     |                  |
+              |                  |     |                  |
+              |     Server 1     |     |     Server 2     |
+              |                  |     |                  |
+              +--------+-`.------+     +------.'+---------+
+                           `.               .'
+                             `.           .'
+                               `.       .'
+                                 `.   .'
+                           +-------`.'--------+
+                           |                  |
+                           |                  |
+                           |     Agent        |
+                           |                  |
+                           +--------+---------+
+                                    |
+                                    |
+                                    |
+                           +--------+---------+
+                           |                  |
+                           |                  |
+                           |     Client       |
+                           |                  |
+                           +------------------+
+
+                 Figure 5: Multiple-Server Agent Scenario
+
+
+
+
+
+
+
+
+
+McMurry & Campbell            Informational                    [Page 12]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+   Figure 6 shows a scenario where an agent routes requests to a set of
+   servers for more than one Diameter realm and application.  In this
+   scenario, if Server 1 becomes overloaded or unavailable while
+   Server 2 still has available capacity, the agent may effectively
+   operate at reduced capacity for Application A but at full capacity
+   for Application B.  Therefore, the agent needs to be able to report
+   that it is overloaded for one application but not for another.
+
+   +--------------------------------------------+
+   | Application A       +----------------------+----------------------+
+   |+------------------+ |  +----------------+  |  +------------------+|
+   ||                  | |  |                |  |  |                  ||
+   ||                  | |  |                |  |  |                  ||
+   ||     Server 1     | |  |    Server 2    |  |  |     Server 3     ||
+   ||                  | |  |                |  |  |                  ||
+   |+---------+--------+ |  +-------+--------+  |  +--+---------------+|
+   |          |          |          |           |     |                |
+   +----------+----------+----------+-----------+     |                |
+              |          |          |                 |                |
+              |          |          |                 | Application B  |
+              |          +----------+-----------------+----------------+
+              |                     |                 |
+               ``--.__              |                _.
+                      ``-.__        |          __.--''
+                            `--.._  |    _..--'
+                            +----``-+.''-----+
+                            |                |
+                            |                |
+                            |    Agent       |
+                            |                |
+                            +-------+--------+
+                                    |
+                                    |
+                            +-------+--------+
+                            |                |
+                            |                |
+                            |    Client      |
+                            |                |
+                            +----------------+
+
+               Figure 6: Multiple-Application Agent Scenario
+
+
+
+
+
+
+
+
+
+
+McMurry & Campbell            Informational                    [Page 13]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+2.3.  Interconnect Scenario
+
+   Another scenario to consider when looking at Diameter overload is
+   that of multiple network operators using Diameter components
+   connected through an interconnect service, e.g., using IPX (IP Packet
+   eXchange).  IPX [IR.34] is an Inter-Operator IP Backbone that
+   provides a roaming interconnection network between mobile operators
+   and service providers.  IPX is also used to transport Diameter
+   signaling between operators [IR.88].  Figure 7 shows two network
+   operators with an interconnect network between them.  There could be
+   any number of these networks between any two network operators'
+   networks.
+
+               +-------------------------------------------+
+               |               Interconnect                |
+               |                                           |
+               |   +--------------+      +--------------+  |
+               |   |   Server 3   |------|   Server 4   |  |
+               |   +--------------+      +--------------+  |
+               |         .'                      `.        |
+               +------.-'--------------------------`.------+
+                    .'                               `.
+                 .-'                                   `.
+   ------------.'-----+                             +----`.-------------
+         +----------+ |                             | +----------+
+         | Server 1 | |                             | | Server 2 |
+         +----------+ |                             | +----------+
+                      |                             |
+   Network Operator 1 |                             | Network Operator 2
+   -------------------+                             +-------------------
+
+                Figure 7: Two-Network Interconnect Scenario
+
+   The characteristics of the information that an operator would want to
+   share over such a connection are different from the information
+   shared between components within a network operator's network.  For
+   example, network operators may not want to convey topology or
+   operational information; this would in turn limit how much overload
+   and loading information can be sent.  For the interconnect scenario
+   shown in Figure 7, Server 2 may want to signal overload to Server 1,
+   to affect traffic coming from Network Operator 1.
+
+   This case is distinct from those internal to a network operator's
+   network, where there may be many more elements in a more complicated
+   topology.  Also, the elements in the interconnect network may not
+   support Diameter overload control, and the network operators may not
+   want the interconnect network to use overload or loading information.
+   They may only want the information to pass through the interconnect
+
+
+
+McMurry & Campbell            Informational                    [Page 14]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+   network without further processing or action by the interconnect
+   network, even if the elements in the interconnect network do support
+   Diameter overload control.
+
+3.  Diameter Overload Case Studies
+
+3.1.  Overload in Mobile Data Networks
+
+   As the number of smartphone devices that are Third Generation (3G)
+   and Long Term Evolution (LTE) enabled continues to expand in mobile
+   networks, there have been situations where high signaling traffic
+   load led to overload events at the Diameter-based Home Location
+   Registers (HLRs) and/or Home Subscriber Servers (HSS) [TR23.843].
+   The root causes of the HLR overload events were manifold but included
+   hardware failure and procedural errors.  The result was high
+   signaling traffic load on the HLR and HSS.
+
+   The 3GPP architecture [TS23.002] makes extensive use of Diameter.  It
+   is used for mobility management [TS29.272], the IP Multimedia
+   Subsystem (IMS) [TS29.228], and policy and charging control
+   [TS29.212], as well as other functions.  The details of the
+   architecture are out of scope for this document, but it is worth
+   noting that there are quite a few Diameter applications, some with
+   quite large amounts of Diameter signaling in deployed networks.
+
+   The 3GPP specifications do not currently address overload for
+   Diameter applications or provide a load control mechanism equivalent
+   to those provided in the more traditional SS7 elements in the Global
+   System for Mobile Communications (GSM); see [TS29.002].  The
+   capabilities specified in the 3GPP standards do not adequately
+   address the abnormal condition where excessively high signaling
+   traffic load situations are experienced.
+
+   Smartphones, which comprise an increasingly large percentage of
+   mobile devices, contribute much more heavily, relative to
+   non-smartphones, to the continuation of a registration surge, due to
+   their very aggressive registration algorithms.  Smartphone behavior
+   contributes to network loading and can contribute to overload
+   conditions.  The aggressive smartphone logic is designed to:
+
+   a.  always have voice and data registration, and
+
+   b.  constantly try to be on 3G or LTE data (and thus on 3G voice or
+       Voice over LTE (VoLTE) [IR.92]) for their added benefits.
+
+   Non-smartphones typically have logic to wait for a time period after
+   registering successfully on voice and data.
+
+
+
+
+McMurry & Campbell            Informational                    [Page 15]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+   The aggressive smartphone registration is problematic in two ways:
+
+   o  first, by generating excessive signaling load towards the HSS that
+      is ten times the load from a non-smartphone, and
+
+   o  second, by causing continual registration attempts when a network
+      failure affects registrations through the 3G data network.
+
+3.2.  3GPP Study on Core Network Overload
+
+   A study in the 3GPP System Aspects working group 2 (SA2) on core
+   network overload has produced the technical report [TR23.843].  This
+   enumerates several causes of overload in mobile core networks,
+   including portions that are signaled using Diameter.  [TR23.843] is a
+   work in progress and is not complete.  However, it is useful for
+   pointing out scenarios and the general need for an overload control
+   mechanism for Diameter.
+
+   It is common for mobile networks to employ more than one radio
+   technology and to do so in an overlay fashion with multiple
+   technologies present in the same location (such as 2nd or 3rd
+   generation mobile technologies, along with LTE).  This presents
+   opportunities for traffic storms when issues occur on one overlay and
+   not another as all devices that had been on the overlay with issues
+   switch.  This causes a large amount of Diameter traffic as locations
+   and policies are updated.
+
+   Another scenario called out by this study is a flood of registration
+   and mobility management events caused by some element in the core
+   network failing.  This flood of traffic from end nodes falls under
+   the network-initiated traffic flood category.  There is likely to
+   also be traffic resulting directly from the component failure in this
+   case.  A similar flood can occur when elements or components recover
+   as well.
+
+   Subscriber-initiated traffic floods are also indicated in this study
+   as an overload mechanism where a large number of mobile devices are
+   attempting to access services at the same time, such as in response
+   to an entertainment event or a catastrophic event.
+
+   While this 3GPP study is concerned with the broader effects of these
+   scenarios on wireless networks and their elements, they have
+   implications specifically for Diameter signaling.  One of the goals
+   of this document is to provide guidance for a core mechanism that can
+   be used to mitigate the scenarios called out by this study.
+
+
+
+
+
+
+McMurry & Campbell            Informational                    [Page 16]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+4.  Existing Mechanisms
+
+   Diameter offers both implicit and explicit mechanisms for a Diameter
+   node to learn that a peer is overloaded or unreachable.  The implicit
+   mechanism is simply the lack of responses to requests.  If a client
+   fails to receive a response in a certain time period, it assumes that
+   the upstream peer is unavailable or is overloaded to the point of
+   effective unavailability.  The watchdog mechanism [RFC3539] ensures
+   that transaction responses occur at a certain rate even when there is
+   otherwise little or no other Diameter traffic.
+
+   The explicit mechanism can involve specific protocol error responses,
+   where an agent or server tells a downstream peer that it is either
+   too busy to handle a request (DIAMETER_TOO_BUSY) or unable to route a
+   request to an upstream destination (DIAMETER_UNABLE_TO_DELIVER)
+   perhaps because that destination itself is overloaded to the point of
+   unavailability.
+
+   Another explicit mechanism, a DPR (Disconnect-Peer-Request) message,
+   can be sent with a Disconnect-Cause of BUSY.  This signals the
+   sender's intent to close the transport connection and requests that
+   the client not reconnect.
+
+   Once a Diameter node learns via one of these mechanisms that an
+   upstream peer has become overloaded, it can then attempt to take
+   action to reduce the load.  This usually means forwarding traffic to
+   an alternate destination, if available.  If no alternate destination
+   is available, the node must either reduce the number of messages it
+   originates (in the case of a client) or inform the client to reduce
+   traffic (in the case of an agent).
+
+   Diameter requires the use of a congestion-managed transport layer,
+   currently TCP or SCTP, to mitigate network congestion.  It is
+   expected that these transports manage network congestion and that
+   issues with transport (e.g., congestion propagation and window
+   management) are managed at that level.  But even with a congestion-
+   managed transport, a Diameter node can become overloaded at the
+   Diameter protocol or application layers due to the causes described
+   in Section 1.2, and congestion-managed transports do not provide
+   facilities (and are at the wrong level) to handle server overload.
+   Transport-level congestion management is also not sufficient to
+   address overload in cases of multi-hop and multi-destination
+   signaling.
+
+
+
+
+
+
+
+
+McMurry & Campbell            Informational                    [Page 17]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+5.  Issues with the Current Mechanisms
+
+   The currently available Diameter mechanisms for indicating an
+   overload condition are not adequate to avoid service outages due to
+   overload.  This inadequacy may, in turn, contribute to broader
+   impacts resulting from overload due to unresponsive Diameter nodes
+   causing application-layer or transport-layer retransmissions.  In
+   particular, they do not allow a Diameter agent or server to shed load
+   as it approaches overload.  At best, a node can only indicate that it
+   needs to entirely stop receiving requests, i.e., that it has
+   effectively failed.  Even that is problematic due to the inability to
+   indicate durational validity on the transient errors available in the
+   base Diameter protocol.  Diameter offers no mechanism to allow a node
+   to indicate different overload states for different categories of
+   messages, for example, if it is overloaded for one Diameter
+   application but not another.
+
+5.1.  Problems with Implicit Mechanism
+
+   The implicit mechanism doesn't allow an agent or server to inform the
+   client of a problem until it is effectively too late to do anything
+   about it.  The client does not know that it needs to take action
+   until the upstream node has effectively failed.  A Diameter node has
+   no opportunity to shed load early to avoid collapse in the first
+   place.
+
+   Additionally, the implicit mechanism cannot distinguish between
+   overload of a Diameter node and network congestion.  Diameter treats
+   the failure to receive an answer as a transport failure.
+
+5.2.  Problems with Explicit Mechanisms
+
+   The Diameter specification is ambiguous on how a client should handle
+   receipt of a DIAMETER_TOO_BUSY response.  The base specification
+   [RFC6733] indicates that the sending client should attempt to send
+   the request to a different peer.  It makes no suggestion that the
+   receipt of a DIAMETER_TOO_BUSY response should affect future Diameter
+   messages in any way.
+
+   The Authentication, Authorization, and Accounting (AAA) Transport
+   Profile [RFC3539] recommends that a AAA node that receives a "Busy"
+   response failover all remaining requests to a different agent or
+   server.  But while the Diameter base specification explicitly depends
+   on [RFC3539] to define transport behavior, it does not refer to
+   [RFC3539] in the description of behavior on receipt of a
+   DIAMETER_TOO_BUSY error.  There's a strong likelihood that at least
+   some implementations will continue to send Diameter requests to an
+   upstream peer even after receiving a DIAMETER_TOO_BUSY error.
+
+
+
+McMurry & Campbell            Informational                    [Page 18]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+   BCP 41 [RFC2914] describes, among other things, how end-to-end
+   application behavior can help avoid congestion collapse.  In
+   particular, an application should avoid sending messages that will
+   never be delivered or processed.  The DIAMETER_TOO_BUSY behavior as
+   described in the Diameter base specification fails at this, since if
+   an upstream node becomes overloaded, a client attempts each request
+   and does not discover the need to failover the request until the
+   initial attempt fails.
+
+   The situation is improved if implementations follow the [RFC3539]
+   recommendation to keep state about upstream peer overload.  But even
+   then, the Diameter specification offers no guidance on how long a
+   client should wait before retrying the overloaded destination.  If an
+   agent or server supports multiple realms and/or applications,
+   DIAMETER_TOO_BUSY offers no way to indicate that it is overloaded for
+   one application but not another.  A DIAMETER_TOO_BUSY error can only
+   indicate overload at a "whole server" scope.
+
+   Agent processing of a DIAMETER_TOO_BUSY response is also problematic
+   as described in the base specification.  DIAMETER_TOO_BUSY is defined
+   as a protocol error.  If an agent receives a protocol error, it may
+   either handle it locally or forward the response back towards the
+   downstream peer.  If a downstream peer receives the DIAMETER_TOO_BUSY
+   response, it may stop sending all requests to the agent for some
+   period of time, even though the agent may still be able to deliver
+   requests to other upstream peers.
+
+   DIAMETER_UNABLE_TO_DELIVER errors, or using DPR with cause code BUSY,
+   also have no mechanisms for specifying the scope or cause of the
+   failure, or the durational validity.
+
+   The issues with error responses described in [RFC6733] extend beyond
+   the particular issues for overload control and have been addressed in
+   an ad hoc fashion by various implementations.  Addressing these in a
+   standard way would be a useful exercise, but it is beyond the scope
+   of this document.
+
+6.  Extensibility and Application Independence
+
+   Given the variety of scenarios in which Diameter elements can be
+   deployed and the variety of roles they can fulfill with Diameter and
+   other technologies, a single algorithm for handling overload may not
+   be sufficient.  For purposes of this discussion, an algorithm is
+   inclusive of behavior for control of overload but does not encompass
+   the general mechanism for transporting control information.  This
+   effort cannot anticipate all possible future scenarios and roles.
+   Extensibility, particularly of algorithms used to deal with overload,
+   will be important to cover these cases.
+
+
+
+McMurry & Campbell            Informational                    [Page 19]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+   Similarly, the scopes to which overload information may apply may
+   include cases that have not yet been considered.  Extensibility in
+   this area will also be important.
+
+   The basic mechanism is intended to be application independent, that
+   is, a Diameter node can use it across any existing and future
+   Diameter applications and expect reasonable results.  Certain
+   Diameter applications might, however, benefit from application-
+   specific behavior over and above the mechanism's defaults.  For
+   example, an application specification might specify relative
+   priorities of messages or selection of a specific overload control
+   algorithm.
+
+7.  Solution Requirements
+
+   This section proposes requirements for an improved mechanism to
+   control Diameter overload, with the goals of addressing the issues
+   described in Section 5 and supporting the scenarios described in
+   Section 2.  These requirements are stated primarily in terms of
+   individual node behavior to inform the design of the improved
+   mechanism; solution designers should keep in mind that the overall
+   goal is improved overall system behavior across all the nodes
+   involved, not just improved behavior from specific individual nodes.
+
+7.1.  General
+
+   REQ 1:  The solution MUST provide a communication method for Diameter
+           nodes to exchange load and overload information.
+
+   REQ 2:  The solution MUST allow Diameter nodes to support overload
+           control regardless of which Diameter applications they
+           support.  Diameter clients and agents must be able to use the
+           received load and overload information to support graceful
+           behavior during an overload condition.  Graceful behavior
+           under overload conditions is best described by REQ 3.
+
+   REQ 3:  The solution MUST limit the impact of overload on the overall
+           useful throughput of a Diameter server, even when the
+           incoming load on the network is far in excess of its
+           capacity.  The overall useful throughput under load is the
+           ultimate measure of the value of a solution.
+
+   REQ 4:  Diameter allows requests to be sent from either side of a
+           connection, and either side of a connection may have need to
+           provide its overload status.  The solution MUST allow each
+           side of a connection to independently inform the other of its
+           overload status.
+
+
+
+
+McMurry & Campbell            Informational                    [Page 20]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+   REQ 5:  Diameter allows nodes to determine their peers via dynamic
+           discovery or manual configuration.  The solution MUST work
+           consistently without regard to how peers are determined.
+
+   REQ 6:  The solution designers SHOULD seek to minimize the amount of
+           new configuration required in order to work.  For example, it
+           is better to allow peers to advertise or negotiate support
+           for the solution, rather than to require that this knowledge
+           be configured at each node.
+
+7.2.  Performance
+
+   REQ 7:  The solution and any associated default algorithm(s) MUST
+           ensure that the system remains stable.  At some point after
+           an overload condition has ended, the solution MUST enable
+           capacity to stabilize and become equal to what it would be in
+           the absence of an overload condition.  Note that this also
+           requires that the solution MUST allow nodes to shed load
+           without introducing non-converging oscillations during or
+           after an overload condition.
+
+   REQ 8:  Supporting nodes MUST be able to distinguish current overload
+           information from stale information.
+
+   REQ 9:  The solution MUST function across fully loaded as well as
+           quiescent transport connections.  This is partially derived
+           from the requirement for stability in REQ 7.
+
+   REQ 10: Consumers of overload information MUST be able to determine
+           when the overload condition improves or ends.
+
+   REQ 11: The solution MUST be able to operate in networks of different
+           sizes.
+
+   REQ 12: When a single network node fails, goes into overload, or
+           suffers from reduced processing capacity, the solution MUST
+           make it possible to limit the impact of the affected node on
+           other nodes in the network.  This helps to prevent a small-
+           scale failure from becoming a widespread outage.
+
+   REQ 13: The solution MUST NOT introduce substantial additional work
+           for a node in an overloaded state.  For example, a
+           requirement for an overloaded node to send overload
+           information every time it received a new request would
+           introduce substantial work.
+
+
+
+
+
+
+McMurry & Campbell            Informational                    [Page 21]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+   REQ 14: Some scenarios that result in overload involve a rapid
+           increase of traffic with little time between normal levels
+           and levels that induce overload.  The solution SHOULD provide
+           for rapid feedback when traffic levels increase.
+
+   REQ 15: The solution MUST NOT interfere with the congestion control
+           mechanisms of underlying transport protocols.  For example, a
+           solution that opened additional TCP connections when the
+           network is congested would reduce the effectiveness of the
+           underlying congestion control mechanisms.
+
+7.3.  Heterogeneous Support for Solution
+
+   REQ 16: The solution is likely to be deployed incrementally.  The
+           solution MUST support a mixed environment where some, but not
+           all, nodes implement it.
+
+   REQ 17: In a mixed environment with nodes that support the solution
+           and nodes that do not, the solution MUST NOT result in
+           materially less useful throughput during overload as would
+           have resulted if the solution were not present.  It SHOULD
+           result in less severe overload in this environment.
+
+   REQ 18: In a mixed environment of nodes that support the solution and
+           nodes that do not, the solution MUST NOT preclude elements
+           that support overload control from treating elements that do
+           not support overload control in an equitable fashion relative
+           to those that do.  Users and operators of nodes that do not
+           support the solution MUST NOT unfairly benefit from the
+           solution.  The solution specification SHOULD provide guidance
+           to implementors for dealing with elements not supporting
+           overload control.
+
+   REQ 19: It MUST be possible to use the solution between nodes in
+           different realms and in different administrative domains.
+
+   REQ 20: Any explicit overload indication MUST be clearly
+           distinguishable from other errors reported via Diameter.
+
+   REQ 21: In cases where a network node fails, is so overloaded that it
+           cannot process messages, or cannot communicate due to a
+           network failure, it may not be able to provide explicit
+           indications of the nature of the failure or its levels of
+           overload.  The solution MUST result in at least as much
+           useful throughput as would have resulted if the solution were
+           not in place.
+
+
+
+
+
+McMurry & Campbell            Informational                    [Page 22]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+7.4.  Granular Control
+
+   REQ 22: The solution MUST provide a way for a node to throttle the
+           amount of traffic it receives from a peer node.  This
+           throttling SHOULD be graded so that it can be applied
+           gradually as offered load increases.  Overload is not a
+           binary state; there may be degrees of overload.
+
+   REQ 23: The solution MUST provide sufficient information to enable a
+           load-balancing node to divert messages that are rejected or
+           otherwise throttled by an overloaded upstream node to other
+           upstream nodes that are the most likely to have sufficient
+           capacity to process them.
+
+   REQ 24: The solution MUST provide a mechanism for indicating load
+           levels, even when not in an overload condition, to assist
+           nodes in making decisions to prevent overload conditions from
+           occurring.
+
+7.5.  Priority and Policy
+
+   REQ 25: The base specification for the solution SHOULD offer general
+           guidance on which message types might be desirable to send or
+           process over others during times of overload, based on
+           application-specific considerations.  For example, it may be
+           more beneficial to process messages for existing sessions
+           ahead of new sessions.  Some networks may have a requirement
+           to give priority to requests associated with emergency
+           sessions.  Any normative or otherwise detailed definition of
+           the relative priorities of message types during an overload
+           condition will be the responsibility of the application
+           specification.
+
+   REQ 26: The solution MUST NOT prevent a node from prioritizing
+           requests based on any local policy, so that certain requests
+           are given preferential treatment, given additional
+           retransmission, not throttled, or processed ahead of others.
+
+7.6.  Security
+
+   REQ 27: The solution MUST NOT provide new vulnerabilities to
+           malicious attack or increase the severity of any existing
+           vulnerabilities.  This includes vulnerabilities to DoS and
+           DDoS attacks as well as replay and man-in-the-middle attacks.
+           Note that the Diameter base specification [RFC6733] lacks
+           end-to-end security, and this must be considered (see
+           Security Considerations in this document (Section 8)).  Note
+
+
+
+
+McMurry & Campbell            Informational                    [Page 23]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+           that this requirement was expressed at a high level so as to
+           not preclude any particular solution.  Is is expected that
+           the solution will address this in more detail.
+
+   REQ 28: The solution MUST NOT depend on being deployed in
+           environments where all Diameter nodes are completely trusted.
+           It SHOULD operate as effectively as possible in environments
+           where other nodes are malicious; this includes preventing
+           malicious nodes from obtaining more than a fair share of
+           service.  Note that this does not imply any responsibility on
+           the solution to detect, or take countermeasures against,
+           malicious nodes.
+
+   REQ 29: It MUST be possible for a supporting node to make
+           authorization decisions about what information will be sent
+           to peer nodes based on the identity of those nodes.  This
+           allows a domain administrator who considers the load of their
+           nodes to be sensitive information to restrict access to that
+           information.  Of course, in such cases, there is no
+           expectation that the solution itself will help prevent
+           overload from that peer node.
+
+   REQ 30: The solution MUST NOT interfere with any Diameter-compliant
+           method that a node may use to protect itself from overload
+           from non-supporting nodes or from denial-of-service attacks.
+
+7.7.  Flexibility and Extensibility
+
+   REQ 31: There are multiple situations where a Diameter node may be
+           overloaded for some purposes but not others.  For example,
+           this can happen to an agent or server that supports multiple
+           applications, or when a server depends on multiple external
+           resources, some of which may become overloaded while others
+           are fully available.  The solution MUST allow Diameter nodes
+           to indicate overload with sufficient granularity to allow
+           clients to take action based on the overloaded resources
+           without unreasonably forcing available capacity to go unused.
+           The solution MUST support specification of overload
+           information with granularities of at least "Diameter node",
+           "realm", and "Diameter application" and MUST allow
+           extensibility for others to be added in the future.
+
+   REQ 32: The solution MUST provide a method for extending the
+           information communicated and the algorithms used for overload
+           control.
+
+
+
+
+
+
+McMurry & Campbell            Informational                    [Page 24]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+   REQ 33: The solution MUST provide a default algorithm that is
+           mandatory to implement.
+
+   REQ 34: The solution SHOULD provide a method for exchanging overload
+           and load information between elements that are connected by
+           intermediaries that do not support the solution.
+
+8.  Security Considerations
+
+   A Diameter overload control mechanism is primarily concerned with the
+   load-related and overload-related behavior of nodes in a Diameter
+   network, and the information used to affect that behavior.  Load and
+   overload information is shared between nodes and directly affects the
+   behavior, and thus the information is potentially vulnerable to a
+   number of methods of attack.
+
+   Load and overload information may also be sensitive from both
+   business and network protection viewpoints.  Operators of Diameter
+   equipment want to control the visibility of load and overload
+   information to keep it from being used for competitive intelligence
+   or for targeting attacks.  It is also important that the Diameter
+   overload control mechanism not introduce any way in which any other
+   information carried by Diameter is sent inappropriately.
+
+   Note that the Diameter base specification [RFC6733] lacks end-to-end
+   security, making it difficult for non-adjacent nodes to verify the
+   authenticity and ownership of load and overload information.
+   Authentication of load and overload information helps to alleviate
+   several of the security issues listed in this section.
+
+   This document includes requirements intended to mitigate the effects
+   of attacks and to protect the information used by the mechanism.
+   This section discusses potential security considerations for overload
+   control solutions.  This discussion provides the motivation for
+   several normative requirements described in Section 7.  The
+   discussion includes specific references to the normative requirements
+   that apply for each issue.
+
+8.1.  Access Control
+
+   To control the visibility of load and overload information, sending
+   should be subject to some form of authentication and authorization of
+   the receiver.  It is also important to the receivers that they are
+   confident the load and overload information they receive is from a
+   legitimate source.  REQ 28 requires that the solution work without
+   assuming that all Diameter nodes in a network are trusted for the
+   purposes of exchanging overload and load information.  REQ 29
+   requires that the solution let nodes restrict unauthorized parties
+
+
+
+McMurry & Campbell            Informational                    [Page 25]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+   from seeing overload information.  Note that this implies a certain
+   amount of configurability on the nodes supporting the Diameter
+   overload control mechanism.
+
+8.2.  Denial-of-Service Attacks
+
+   An overload control mechanism provides a very attractive target for
+   denial-of-service attacks.  A small number of messages may effect a
+   large service disruption by falsely reporting overload conditions.
+   Alternately, attacking servers nearing, or in, overload may also be
+   facilitated by disrupting their overload indications, potentially
+   preventing them from mitigating their overload condition.
+
+   A design goal for the Diameter overload control mechanism is to
+   minimize or eliminate the possibility of using the mechanism for this
+   type of attack.  More strongly, REQ 27 forbids the solution from
+   introducing new vulnerabilities to malicious attack.  Additionally,
+   REQ 30 stipulates that the solution not interfere with other
+   mechanisms used for protection against denial-of-service attacks.
+
+   As the intent of some denial-of-service attacks is to induce overload
+   conditions, an effective overload control mechanism should help to
+   mitigate the effects of such an attack.
+
+8.3.  Replay Attacks
+
+   An attacker that has managed to obtain some messages from the
+   overload control mechanism may attempt to affect the behavior of
+   nodes supporting the mechanism by sending those messages at
+   potentially inopportune times.  In addition to time shifting, replay
+   attacks may send messages to other nodes as well (target shifting).
+
+   A design goal for the Diameter overload control solution is to
+   minimize or eliminate the possibility of causing disruption by using
+   a replay attack on the Diameter overload control mechanism.
+   (Allowing a replay attack using the overload control solution would
+   violate REQ 27.)
+
+8.4.  Man-in-the-Middle Attacks
+
+   By inserting themselves between two nodes supporting the Diameter
+   overload control mechanism, an attacker may potentially both access
+   and alter the information sent between those nodes.  This can be used
+   for information gathering for business intelligence and attack
+   targeting, as well as direct attacks.
+
+
+
+
+
+
+McMurry & Campbell            Informational                    [Page 26]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+   REQs 27, 28, and 29 imply a need to prevent man-in-the-middle attacks
+   on the overload control solution.  A transport using Transport Layer
+   Security (TLS) and/or IPsec may be desirable for this purpose.
+
+8.5.  Compromised Hosts
+
+   A compromised host that supports the Diameter overload control
+   mechanism could be used for information gathering as well as for
+   sending malicious information to any Diameter node that would
+   normally accept information from it.  While it is beyond the scope of
+   the Diameter overload control mechanism to mitigate any operational
+   interruption to the compromised host, REQs 28 and 29 imply a need to
+   minimize the impact that a compromised host can have on other nodes
+   through the use of the Diameter overload control mechanism.  Of
+   course, a compromised host could be used to cause damage in a number
+   of other ways.  This is out of scope for a Diameter overload control
+   mechanism.
+
+9.  References
+
+9.1.  Normative References
+
+   [RFC2119]   Bradner, S., "Key words for use in RFCs to Indicate
+               Requirement Levels", BCP 14, RFC 2119, March 1997.
+
+   [RFC6733]   Fajardo, V., Arkko, J., Loughney, J., and G. Zorn,
+               "Diameter Base Protocol", RFC 6733, October 2012.
+
+   [RFC2914]   Floyd, S., "Congestion Control Principles", BCP 41,
+               RFC 2914, September 2000.
+
+   [RFC3539]   Aboba, B. and J. Wood, "Authentication, Authorization and
+               Accounting (AAA) Transport Profile", RFC 3539, June 2003.
+
+9.2.  Informative References
+
+   [RFC5390]   Rosenberg, J., "Requirements for Management of Overload
+               in the Session Initiation Protocol", RFC 5390,
+               December 2008.
+
+   [RFC6357]   Hilt, V., Noel, E., Shen, C., and A. Abdelal, "Design
+               Considerations for Session Initiation Protocol (SIP)
+               Overload Control", RFC 6357, August 2011.
+
+   [TR23.843]  3GPP, "Study on Core Network (CN) overload solutions",
+               TR 23.843 1.2.0, Work in Progress, October 2013.
+
+
+
+
+
+McMurry & Campbell            Informational                    [Page 27]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+   [IR.34]     GSMA, "Inter-Service Provider IP Backbone Guidelines",
+               IR 34 9.1, May 2013.
+
+   [IR.88]     GSMA, "LTE Roaming Guidelines", IR 88 9.0, January 2013.
+
+   [IR.92]     GSMA, "IMS Profile for Voice and SMS", IR 92 7.0,
+               March 2013.
+
+   [TS23.002]  3GPP, "Network Architecture", TS 23.002 12.2.0,
+               June 2013.
+
+   [TS29.272]  3GPP, "Evolved Packet System (EPS); Mobility Management
+               Entity (MME) and Serving GPRS Support Node (SGSN) related
+               interfaces based on Diameter protocol", TS 29.272 12.2.0,
+               September 2013.
+
+   [TS29.212]  3GPP, "Policy and Charging Control (PCC) over Gx/Sd
+               reference point", TS 29.212 12.2.0, September 2013.
+
+   [TS29.228]  3GPP, "IP Multimedia (IM) Subsystem Cx and Dx interfaces;
+               Signalling flows and message contents", TS 29.228 12.0.0,
+               September 2013.
+
+   [TS29.002]  3GPP, "Mobile Application Part (MAP) specification",
+               TS 29.002 12.2.0, September 2013.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+McMurry & Campbell            Informational                    [Page 28]
+
+RFC 7068         Diameter Overload Control Requirements    November 2013
+
+
+Appendix A.  Contributors
+
+   Significant contributions to this document were made by Adam Roach
+   and Eric Noel.
+
+Appendix B.  Acknowledgements
+
+   Review of, and contributions to, this specification by Martin Dolly,
+   Carolyn Johnson, Jianrong Wang, Imtiaz Shaikh, Jouni Korhonen, Robert
+   Sparks, Dieter Jacobsohn, Janet Gunn, Jean-Jacques Trottin, Laurent
+   Thiebaut, Andrew Booth, and Lionel Morand were most appreciated.  We
+   would like to thank them for their time and expertise.
+
+Authors' Addresses
+
+   Eric McMurry
+   Oracle
+   17210 Campbell Rd.
+   Suite 250
+   Dallas, TX  75252
+   US
+
+   EMail: [email protected]
+
+
+   Ben Campbell
+   Oracle
+   17210 Campbell Rd.
+   Suite 250
+   Dallas, TX  75252
+   US
+
+   EMail: [email protected]
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+McMurry & Campbell            Informational                    [Page 29]
+
diff --git a/lib/diameter/doc/standard/rfc7075.txt b/lib/diameter/doc/standard/rfc7075.txt
new file mode 100644
index 0000000000..f5fd905e72
--- /dev/null
+++ b/lib/diameter/doc/standard/rfc7075.txt
@@ -0,0 +1,563 @@
+
+
+
+
+
+
+Internet Engineering Task Force (IETF)                           T. Tsou
+Request for Comments: 7075                     Huawei Technologies (USA)
+Updates: 6733                                                     R. Hao
+Category: Standards Track                                  Comcast Cable
+ISSN: 2070-1721                                           T. Taylor, Ed.
+                                                     Huawei Technologies
+                                                           November 2013
+
+
+                  Realm-Based Redirection In Diameter
+
+Abstract
+
+   The Diameter protocol includes a capability for message redirection,
+   controlled by an application-independent "redirect agent".  In some
+   circumstances, an operator may wish to redirect messages to an
+   alternate domain without specifying individual hosts.  This document
+   specifies an application-specific mechanism by which a Diameter
+   server or proxy (node) can perform such a redirection when the
+   Straightforward-Naming Authority Pointer (S-NAPTR) is not used for
+   dynamic peer discovery.  A node performing this new function is
+   referred to as a "Realm-based Redirect Server".
+
+   This memo updates Sections 6.13 and 6.14 of RFC 6733 with respect to
+   the usage of the Redirect-Host-Usage and Redirect-Max-Cache-Time
+   Attribute-Value Pairs (AVPs).
+
+Status of This Memo
+
+   This is an Internet Standards Track document.
+
+   This document is a product of the Internet Engineering Task Force
+   (IETF).  It represents the consensus of the IETF community.  It has
+   received public review and has been approved for publication by the
+   Internet Engineering Steering Group (IESG).  Further information on
+   Internet Standards is available in Section 2 of RFC 5741.
+
+   Information about the current status of this document, any errata,
+   and how to provide feedback on it may be obtained at
+   http://www.rfc-editor.org/info/rfc7075.
+
+
+
+
+
+
+
+
+
+
+
+Tsou, et al.                 Standards Track                    [Page 1]
+
+RFC 7075           Realm-Based Redirection In Diameter     November 2013
+
+
+Copyright Notice
+
+   Copyright (c) 2013 IETF Trust and the persons identified as the
+   document authors.  All rights reserved.
+
+   This document is subject to BCP 78 and the IETF Trust's Legal
+   Provisions Relating to IETF Documents
+   (http://trustee.ietf.org/license-info) in effect on the date of
+   publication of this document.  Please review these documents
+   carefully, as they describe your rights and restrictions with respect
+   to this document.  Code Components extracted from this document must
+   include Simplified BSD License text as described in Section 4.e of
+   the Trust Legal Provisions and are provided without warranty as
+   described in the Simplified BSD License.
+
+Table of Contents
+
+   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
+     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
+   2.  Support of Realm-Based Redirection Within Applications  . . .   4
+   3.  Realm-Based Redirection . . . . . . . . . . . . . . . . . . .   5
+     3.1.  Configuration of the Realm-Based Redirect Server  . . . .   5
+     3.2.  Behavior of Diameter Nodes  . . . . . . . . . . . . . . .   6
+       3.2.1.  Behavior at the Realm-Based Redirect Server . . . . .   6
+       3.2.2.  Proxy Behavior  . . . . . . . . . . . . . . . . . . .   6
+       3.2.3.  Client Behavior . . . . . . . . . . . . . . . . . . .   7
+     3.3.  The Redirect-Realm AVP  . . . . . . . . . . . . . . . . .   7
+     3.4.  DIAMETER_REALM_REDIRECT_INDICATION Protocol Error Code  .   7
+   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
+   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
+   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   9
+   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
+     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   9
+     7.2.  Informative References  . . . . . . . . . . . . . . . . .   9
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Tsou, et al.                 Standards Track                    [Page 2]
+
+RFC 7075           Realm-Based Redirection In Diameter     November 2013
+
+
+1.  Introduction
+
+   The Diameter base protocol [RFC6733] specifies a basic redirection
+   service provided by a redirect agent.  The redirect indication
+   returned by the redirect agent is described in Section 6.1.8 and
+   Sections 6.12 through 6.14 of [RFC6733].  It provides one or more
+   individual hosts to the message sender as the destination of the
+   redirected message.
+
+   However, consider the case where an operator has offered a specific
+   service but no longer wishes to do so.  The operator has arranged for
+   an alternative domain to provide the service.  To aid in the
+   transition to the new arrangement, the original operator maintains a
+   redirect server to indicate to the message sender the alternative
+   domain to which the redirect the request should be sent.  However,
+   the original operator should not have to configure the redirect
+   server with a list of hosts to contact in the alternative operator's
+   domain; the original operator should simply be able to provide
+   redirect indications to the domain as a whole.
+
+1.1.  Terminology
+
+   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
+   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
+   document are to be interpreted as described in [RFC2119].
+
+   Within this specification, the term "realm-based redirection" is used
+   to refer to a mode of operation where a realm, rather than an
+   individual host, is returned as the redirect indication.
+
+   The term "Realm-based Redirect Server" denotes the Diameter node
+   (Diameter server or proxy) that returns the realm-based redirection.
+   The behavior of the Realm-based Redirect Server itself is a slight
+   modification to the behavior of a basic redirect agent as described
+   in Section 6.1.8 of [RFC6733].
+
+   The use of a number of terms in this document is consistent with the
+   usage in [RFC6733]: "Diameter client", "Diameter node", "Diameter
+   peer", "Diameter server", "proxy", "realm" or "domain", "redirect
+   agent", and "session" as defined in Section 1.2, and "application" as
+   defined implicitly by Sections 1.3.4, 2.3, and 2.4.
+
+
+
+
+
+
+
+
+
+
+Tsou, et al.                 Standards Track                    [Page 3]
+
+RFC 7075           Realm-Based Redirection In Diameter     November 2013
+
+
+2.  Support of Realm-Based Redirection Within Applications
+
+   The DNS-based dynamic peer discovery mechanism defined in the
+   Diameter base protocol [RFC6733] provides a simple mechanism for
+   realm-based redirection using the S-NAPTR DDDS application [RFC3958].
+   When S-NAPTR is used for peer discovery, redirection of Diameter
+   requests from the original realm to a new realm may be performed by
+   updating the existing NAPTR resource records (RRs) for the original
+   realm as follows: the NAPTR RR for the desired application(s) and
+   supported application protocol(s) provided by the new realm will have
+   an empty FLAG field and the REPLACEMENT field will contain the new
+   realm to use for the next DNS lookup.  The new realm can be
+   arbitrary; the restriction in [RFC6733] that the NAPTR replacement
+   field match the domain of the original query does not apply for
+   realm-based redirect purposes.
+
+   However, the use of DNS-based dynamic peer discovery is optional for
+   Diameter implementations.  For deployments that do not make use of
+   S-NAPTR peer discovery, support of realm-based redirection needs to
+   be specified as part of the functionality supported by a Diameter
+   application.  In this way, support of the considered Diameter
+   application (discovered during capabilities exchange phase as defined
+   in Diameter base protocol [RFC6733]) indicates implicit support of
+   the realm-based redirection mechanism.  A new application
+   specification can incorporate the mechanism specified here by making
+   it mandatory to implement for the application and referencing this
+   specification normatively.
+
+   The result of making realm-based redirection an application-specific
+   behavior is that it cannot be performed by a redirect agent as
+   defined in [RFC6733], but MUST be performed instead by an
+   application-aware Diameter node (Diameter server or proxy) (hereafter
+   called a "Realm-based Redirect Server").
+
+   An application can specify that realm-based redirection operates only
+   on complete sessions beginning with the initial message or on every
+   message within the application, even if earlier messages of the same
+   session were not redirected.  This distinction matters only when
+   realm-based redirection is first initiated.  In the former case,
+   existing sessions will not be disrupted by the deployment of realm-
+   based redirection.  In the latter case, existing sessions will be
+   disrupted if they are stateful.
+
+
+
+
+
+
+
+
+
+Tsou, et al.                 Standards Track                    [Page 4]
+
+RFC 7075           Realm-Based Redirection In Diameter     November 2013
+
+
+3.  Realm-Based Redirection
+
+   This section specifies an extension of the Diameter base protocol
+   [RFC6733] to achieve realm-based redirection.  The elements of this
+   solution are:
+
+   o  a new result code, DIAMETER_REALM_REDIRECT_INDICATION (3011);
+
+   o  a new attribute-value pair (AVP), Redirect-Realm (620); and
+
+   o  associated behavior at Diameter nodes implementing this
+      specification.
+
+   This behavior includes the optional use of the Redirect-Host-Usage
+   and Redirect-Max-Cache-Time AVPs.  In this document, these AVPs apply
+   to the peer discovered by a node acting on the redirect server's
+   response, an extension to their normal usage as described in Sections
+   6.13 and 6.14 of [RFC6733].
+
+   Section 3.2.2 and Section 3.2.3 describe how a proxy or client may
+   update its routing table for the application and initial realm as a
+   result of selecting a peer in the new realm after realm-based
+   redirection.  Note that as a result, the proxy or client will
+   automatically route subsequent requests for that application to the
+   new realm (with the possible exception of requests within sessions
+   already established with the initial realm) until the cached routing
+   entry expires.  This should be borne in mind if the rerouting is
+   intended to be temporary.
+
+3.1.  Configuration of the Realm-Based Redirect Server
+
+   A Diameter node (Diameter server or proxy) acting as a Realm-based
+   Redirect Server MUST be configured as follows to execute realm-based
+   redirection:
+
+   o  configured with an application that incorporates realm-based
+      redirection;
+
+   o  the Local Action field of the routing table described in
+      Section 2.7 of [RFC6733] is set to LOCAL;
+
+   o  an application-specific field is set to indicate that the required
+      local action is to perform realm-based redirection;
+
+   o  an associated application-specific field is configured with the
+      identities of one or more realms to which the request should be
+      redirected.
+
+
+
+
+Tsou, et al.                 Standards Track                    [Page 5]
+
+RFC 7075           Realm-Based Redirection In Diameter     November 2013
+
+
+3.2.  Behavior of Diameter Nodes
+
+3.2.1.  Behavior at the Realm-Based Redirect Server
+
+   As mentioned in Section 2, an application can specify that realm-
+   based redirection operates only on complete sessions beginning with
+   the initial message (i.e., to prevent disruption of established
+   sessions) or on every message within the application, even if earlier
+   messages of the same session were not redirected.
+
+   If a Realm-based Redirect Server configured as described in
+   Section 3.1 receives a request to which realm-based redirection
+   applies, the Realm-based Redirect Server MUST reply with an answer
+   message with the 'E' bit set, while maintaining the Hop-by-Hop
+   Identifier in the header.  The Realm-based Redirect Server MUST
+   include the Result-Code AVP set to
+   DIAMETER_REALM_REDIRECT_INDICATION.  The Realm-based Redirect Server
+   MUST also include the alternate realm identifier(s) with which it has
+   been configured, each in a separate Redirect-Realm AVP instance.
+
+   The Realm-based Redirect Server MAY include a copy of the Redirect-
+   Host-Usage AVP, which SHOULD be set to REALM_AND_APPLICATION.  If
+   this AVP is added, the Redirect-Max-Cache-Time AVP MUST also be
+   included.  Note that these AVPs apply to the peer discovered by a
+   node acting on the Realm-based Redirect Server's response as
+   described in the next section.  This is an extension of their normal
+   usage as described by Sections 6.13 and 6.14 of [RFC6733].
+
+      Realm-based redirection MAY be applied even if a Destination-Host
+      AVP is present in the request, depending on the operator-based
+      policy.
+
+3.2.2.  Proxy Behavior
+
+   A proxy conforming to this specification that receives an answer
+   message with the Result-Code AVP set to
+   DIAMETER_REALM_REDIRECT_INDICATION MUST attempt to reroute the
+   original request to a server in a realm identified by a Redirect-
+   Realm AVP instance in the answer message, and if it fails MUST
+   forward the indication toward the client.  To reroute the request, it
+   MUST take the following actions:
+
+   1.  Select a specific realm from amongst those identified in
+       instances of the Redirect-Realm AVP in the answer message.
+
+   2.  If successful, locate and establish a route to a peer in the
+       realm given by the Redirect-Realm AVP, using normal discovery
+       procedures as described in Section 5.2 of [RFC6733].
+
+
+
+Tsou, et al.                 Standards Track                    [Page 6]
+
+RFC 7075           Realm-Based Redirection In Diameter     November 2013
+
+
+   3.  If again successful:
+
+       A.  update its cache of routing entries for the realm and
+           application to which the original request was directed,
+           taking into account the Redirect-Host-Usage and Redirect-Max-
+           Cache-Time AVPs, if present in the answer.
+
+       B.  Remove the Destination-Host (if present) and Destination-
+           Realm AVPs from the original request and add a new
+           Destination-Realm AVP containing the realm selected in the
+           initial step.
+
+       C.  Forward the modified request.
+
+   4.  If either of the preceding steps 2-3 fail and additional realms
+       have been identified in the original answer, select another
+       instance of the Redirect-Realm AVP in that answer and repeat
+       steps 2-3 for the realm that it identifies.
+
+3.2.3.  Client Behavior
+
+   A client conforming to this specification MUST be prepared to receive
+   either an answer message containing a Result-Code AVP set to
+   DIAMETER_REALM_REDIRECT_INDICATION, or, as the result of proxy
+   action, some other result from a realm differing from the one to
+   which it sent the original request.  In the case where it receives
+   DIAMETER_REALM_REDIRECT_INDICATION, the client SHOULD follow the same
+   steps prescribed in the previous section for a proxy, in order to
+   both update its routing table and obtain service for the original
+   request.
+
+3.3.  The Redirect-Realm AVP
+
+   The Redirect-Realm AVP (620) is of type DiameterIdentity.  It
+   specifies a realm to which a node receiving a redirect indication
+   containing the result code value DIAMETER_REALM_REDIRECT_INDICATION
+   and the Redirect-Realm AVP SHOULD route the original request.
+
+3.4.  DIAMETER_REALM_REDIRECT_INDICATION Protocol Error Code
+
+   The DIAMETER_REALM_REDIRECT_INDICATION (3011) Protocol error code
+   indicates that a server has determined that the request within an
+   application supporting realm-based redirection could not be satisfied
+   locally, and the initiator of the request SHOULD direct the request
+   directly to a peer within a realm that has been identified in the
+   response.  When set, the Redirect-Realm AVP MUST be present.
+
+
+
+
+
+Tsou, et al.                 Standards Track                    [Page 7]
+
+RFC 7075           Realm-Based Redirection In Diameter     November 2013
+
+
+4.  Security Considerations
+
+   The general recommendations given in Section 13 of the Diameter base
+   protocol [RFC6733] apply.  Specific security recommendations related
+   to the realm-based redirection defined in this document are described
+   below.
+
+   Realm-based redirection implies a change in the business relationship
+   between organizations.  Before redirecting a request towards a realm
+   different from the initial realm, the client or proxy MUST ensure
+   that the authorization checks have been performed at each connection
+   along the path toward the realm identified in the realm-based
+   redirect indication.  Details on Diameter authorization path set-up
+   are given in Section 2.9 of [RFC6733].  Section 13 of [RFC6733]
+   provides recommendations on how to authenticate and secure each peer-
+   to-peer connection (using TLS, DTLS, or IPsec) along the way, thus
+   permitting the necessary hop-by-hop authorization checks.
+
+   Although it is assumed that the administrative domains are secure, a
+   compromised Diameter node acting as a Realm-based Redirect Server
+   would be able to redirect a large number of Diameter requests towards
+   a victim domain that would then be flooded with undesired Diameter
+   requests.  Such an attack is nevertheless discouraged by the use of
+   secure Diameter peer-to-peer connections and authorization checks,
+   since these would enable a potential victim domain to discover from
+   where an attack is coming.  That in itself, however, does not prevent
+   such a DoS attack.
+
+   Because realm-based redirection defined in this document implies that
+   the Destination-Realm AVP in a client-initiated request can be
+   changed by a Diameter proxy in the path between the client and the
+   server, any cryptographic algorithm that would use the Destination-
+   Realm AVP as input to the calculation performed by the client and the
+   server would be broken by this form of redirection.  Application
+   specifications that would rely on such cryptographic algorithms
+   SHOULD NOT incorporate this realm-based redirection.
+
+5.  IANA Considerations
+
+   This specification allocates a new AVP code Redirect-Realm (620) in
+   the "AVP Codes" registry under "Authentication, Authorization, and
+   Accounting (AAA) Parameters".
+
+   This specification allocates a new Result-Code value
+   DIAMETER_REALM_REDIRECT_INDICATION (3011) in the "Result-Code AVP
+   Values (code 268) - Protocol Errors" registry under "Authentication,
+   Authorization, and Accounting (AAA) Parameters".
+
+
+
+
+Tsou, et al.                 Standards Track                    [Page 8]
+
+RFC 7075           Realm-Based Redirection In Diameter     November 2013
+
+
+6.  Acknowledgements
+
+   Glen Zorn, Sebastien Decugis, Wolfgang Steigerwald, Mark Jones,
+   Victor Fajardo, Jouni Korhonen, Avi Lior, and Lionel Morand
+   contributed comments that helped to shape this document.  As
+   shepherd, Lionel contributed a second set of comments that added
+   polish to the document before it was submitted to the IESG.  Benoit
+   Claise picked up additional points that were quickly resolved with
+   Lionel's help.  During IETF Last Call Review, Enrico Marocco picked
+   up some important editorial corrections.  Stefan Winter contributed
+   text on the use of S-NAPTR as an alternative method of realm-based
+   redirection already specified in [RFC6733].  Derek Atkins performed a
+   review on behalf of the Security Directorate.  Lionel noted one more
+   correction.
+
+   Finally, this document benefited from comments and discussion raised
+   by IESG members Stewart Bryant, Stephen Farrell, Barry Leiba, Pete
+   Resnick, Jari Arkko, and Sean Turner during IESG review.
+
+   The authors are very grateful to Lionel Morand for his active role as
+   document shepherd.  At each stage, he worked to summarize and resolve
+   comments, making the editor's role easy.  Thank you.
+
+7.  References
+
+7.1.  Normative References
+
+   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
+              Requirement Levels", BCP 14, RFC 2119, March 1997.
+
+   [RFC6733]  Fajardo, V., Arkko, J., Loughney, J., and G. Zorn,
+              "Diameter Base Protocol", RFC 6733, October 2012.
+
+7.2.  Informative References
+
+   [RFC3958]  Daigle, L. and A. Newton, "Domain-Based Application
+              Service Location Using SRV RRs and the Dynamic Delegation
+              Discovery Service (DDDS)", RFC 3958, January 2005.
+
+
+
+
+
+
+
+
+
+
+
+
+
+Tsou, et al.                 Standards Track                    [Page 9]
+
+RFC 7075           Realm-Based Redirection In Diameter     November 2013
+
+
+Authors' Addresses
+
+   Tina Tsou
+   Huawei Technologies (USA)
+   2330 Central Expressway
+   Santa Clara, CA  95050
+   USA
+
+   Phone: +1 408 330 4424
+   EMail: [email protected]
+   URI:   http://tinatsou.weebly.com/contact.html
+
+
+   Ruibing Hao
+   Comcast Cable
+   One Comcast Center
+   Philadelphia, PA  19103
+   USA
+
+   Phone: +1 215 286 3991(O)
+   EMail: [email protected]
+
+
+   Tom Taylor (editor)
+   Huawei Technologies
+   Ottawa
+   Canada
+
+   EMail: [email protected]
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Tsou, et al.                 Standards Track                   [Page 10]
+