merge heads

19 files changed, 379 insertions, 378 deletions

diff --git a/.hgignore b/.hgignore
index 7b796b66..03b60914 100644
--- a/.hgignore
+++ b/.hgignore
@@ -11,7 +11,7 @@ syntax: regexp
 ^dist/
 ^include/rabbit_framing\.hrl$
 ^include/rabbit_framing_spec\.hrl$
-^src/rabbit_framing\.erl$
+^src/rabbit_framing_amqp.*\.erl$
 ^src/.*\_usage.erl$
 ^rabbit\.plt$
 ^basic.plt$
diff --git a/Makefile b/Makefile
index 5694292d..a97838cc 100644
--- a/Makefile
+++ b/Makefile
@@ -12,7 +12,7 @@ EBIN_DIR=ebin
 INCLUDE_DIR=include
 DOCS_DIR=docs
 INCLUDES=$(wildcard $(INCLUDE_DIR)/*.hrl) $(INCLUDE_DIR)/rabbit_framing.hrl
-SOURCES=$(wildcard $(SOURCE_DIR)/*.erl) $(SOURCE_DIR)/rabbit_framing.erl $(USAGES_ERL)
+SOURCES=$(wildcard $(SOURCE_DIR)/*.erl) $(SOURCE_DIR)/rabbit_framing_amqp_0_9_1.erl $(SOURCE_DIR)/rabbit_framing_amqp_0_8.erl $(USAGES_ERL)
 BEAM_TARGETS=$(patsubst $(SOURCE_DIR)/%.erl, $(EBIN_DIR)/%.beam, $(SOURCES))
 TARGETS=$(EBIN_DIR)/rabbit.app $(INCLUDE_DIR)/rabbit_framing.hrl $(BEAM_TARGETS)
 WEB_URL=http://www.rabbitmq.com/
@@ -56,7 +56,8 @@ TARGET_SRC_DIR=dist/$(TARBALL_NAME)
 
 SIBLING_CODEGEN_DIR=../rabbitmq-codegen/
 AMQP_CODEGEN_DIR=$(shell [ -d $(SIBLING_CODEGEN_DIR) ] && echo $(SIBLING_CODEGEN_DIR) || echo codegen)
-AMQP_SPEC_JSON_FILES=$(AMQP_CODEGEN_DIR)/amqp-0.8.json $(AMQP_CODEGEN_DIR)/rabbitmq-0.8-extensions.json
+AMQP_SPEC_JSON_FILES_0_9_1=$(AMQP_CODEGEN_DIR)/amqp-rabbitmq-0.9.1.json
+AMQP_SPEC_JSON_FILES_0_8=$(AMQP_CODEGEN_DIR)/amqp-rabbitmq-0.8.json
 
 ERL_CALL=erl_call -sname $(RABBITMQ_NODENAME) -e
 
@@ -99,11 +100,14 @@ $(EBIN_DIR)/rabbit.app: $(EBIN_DIR)/rabbit_app.in $(BEAM_TARGETS) generate_app
 $(EBIN_DIR)/%.beam:
 	erlc $(ERLC_OPTS) -pa $(EBIN_DIR) $<
 
-$(INCLUDE_DIR)/rabbit_framing.hrl: codegen.py $(AMQP_CODEGEN_DIR)/amqp_codegen.py $(AMQP_SPEC_JSON_FILES)
-	$(PYTHON) codegen.py header $(AMQP_SPEC_JSON_FILES) $@
+$(INCLUDE_DIR)/rabbit_framing.hrl: codegen.py $(AMQP_CODEGEN_DIR)/amqp_codegen.py $(AMQP_SPEC_JSON_FILES_0_9_1) $(AMQP_SPEC_JSON_FILES_0_8)
+	$(PYTHON) codegen.py --ignore-conflicts header $(AMQP_SPEC_JSON_FILES_0_9_1) $(AMQP_SPEC_JSON_FILES_0_8) $@
 
-$(SOURCE_DIR)/rabbit_framing.erl: codegen.py $(AMQP_CODEGEN_DIR)/amqp_codegen.py $(AMQP_SPEC_JSON_FILES)
-	$(PYTHON) codegen.py body   $(AMQP_SPEC_JSON_FILES) $@
+$(SOURCE_DIR)/rabbit_framing_amqp_0_9_1.erl: codegen.py $(AMQP_CODEGEN_DIR)/amqp_codegen.py $(AMQP_SPEC_JSON_FILES_0_9_1)
+	$(PYTHON) codegen.py body $(AMQP_SPEC_JSON_FILES_0_9_1) $@
+
+$(SOURCE_DIR)/rabbit_framing_amqp_0_8.erl: codegen.py $(AMQP_CODEGEN_DIR)/amqp_codegen.py $(AMQP_SPEC_JSON_FILES_0_8)
+	$(PYTHON) codegen.py body $(AMQP_SPEC_JSON_FILES_0_8) $@
 
 dialyze: $(BEAM_TARGETS) $(BASIC_PLT)
 	$(ERL_EBIN) -eval \
@@ -128,7 +132,7 @@ $(BASIC_PLT): $(BEAM_TARGETS)
 clean:
 	rm -f $(EBIN_DIR)/*.beam
 	rm -f $(EBIN_DIR)/rabbit.app $(EBIN_DIR)/rabbit.boot $(EBIN_DIR)/rabbit.script $(EBIN_DIR)/rabbit.rel
-	rm -f $(INCLUDE_DIR)/rabbit_framing.hrl $(SOURCE_DIR)/rabbit_framing.erl codegen.pyc
+	rm -f $(INCLUDE_DIR)/rabbit_framing.hrl $(SOURCE_DIR)/rabbit_framing_amqp_*.erl codegen.pyc
 	rm -f $(DOCS_DIR)/*.[0-9].gz $(DOCS_DIR)/*.man.xml $(DOCS_DIR)/*.erl $(USAGES_ERL)
 	rm -f $(RABBIT_PLT)
 	rm -f $(DEPS_FILE)
diff --git a/codegen.py b/codegen.py
index 1244aae1..230d785e 100644
--- a/codegen.py
+++ b/codegen.py
@@ -315,11 +315,16 @@ def genErl(spec):
     methods = spec.allMethods()
 
     printFileHeader()
-    print """-module(rabbit_framing).
--include("rabbit_framing.hrl").
-
+    module = "rabbit_framing_amqp_%d_%d" % (spec.major, spec.minor)
+    if spec.revision != 0:
+        module = "%s_%d" % (module, spec.revision)
+    if module == "rabbit_framing_amqp_8_0":
+        module = "rabbit_framing_amqp_0_8"
+    print "-module(%s)." % module
+    print """-include("rabbit_framing.hrl").
+
+-export([version/0]).
 -export([lookup_method_name/1]).
-
 -export([method_id/1]).
 -export([method_has_content/1]).
 -export([is_method_synchronous/1]).
@@ -395,6 +400,7 @@ def genErl(spec):
     print """
 %% Method signatures
 -ifdef(use_specs).
+-spec(version/0 :: () -> {non_neg_integer(), non_neg_integer(), non_neg_integer()}).
 -spec(lookup_method_name/1 :: (amqp_method()) -> amqp_method_name()).
 -spec(method_id/1 :: (amqp_method_name()) -> amqp_method()).
 -spec(method_has_content/1 :: (amqp_method_name()) -> boolean()).
@@ -413,6 +419,10 @@ bitvalue(true) -> 1;
 bitvalue(false) -> 0;
 bitvalue(undefined) -> 0.
 """
+    version = "{%d, %d, %d}" % (spec.major, spec.minor, spec.revision)
+    if version == '{8, 0, 0}': version = '{0, 8, 0}'
+    print "version() -> %s." % (version)
+
     for m in methods: genLookupMethodName(m)
     print "lookup_method_name({_ClassId, _MethodId} = Id) -> exit({unknown_method_id, Id})."
 
@@ -471,8 +481,6 @@ def genHrl(spec):
     methods = spec.allMethods()
 
     printFileHeader()
-    print "-define(PROTOCOL_VERSION_MAJOR, %d)." % (spec.major)
-    print "-define(PROTOCOL_VERSION_MINOR, %d)." % (spec.minor)
     print "-define(PROTOCOL_PORT, %d)." % (spec.port)
 
     for (c,v,cls) in spec.constants:
diff --git a/docs/rabbitmqctl.1.xml b/docs/rabbitmqctl.1.xml
index e53a97c2..a7d064f1 100644
--- a/docs/rabbitmqctl.1.xml
+++ b/docs/rabbitmqctl.1.xml
@@ -888,6 +888,10 @@
                 <listitem><para>Number of channels using the connection.</para></listitem>
               </varlistentry>
               <varlistentry>
+                <term>protocol</term>
+                <listitem><para>Version of the AMQP protocol in use (currently one of <command>{0,9,1}</command> or <command>{0,8,0}</command>). Note that if a client requests an AMQP 0-9 connection, we treat it as AMQP 0-9-1.</para></listitem>
+              </varlistentry>
+              <varlistentry>
                 <term>user</term>
                 <listitem><para>Username associated with the connection.</para></listitem>
               </varlistentry>
diff --git a/include/rabbit.hrl b/include/rabbit.hrl
index 3fd52568..6364d60f 100644
--- a/include/rabbit.hrl
+++ b/include/rabbit.hrl
@@ -36,7 +36,8 @@
 
 -record(vhost, {virtual_host, dummy}).
 
--record(connection, {user, timeout_sec, frame_max, vhost, client_properties}).
+-record(connection, {protocol, user, timeout_sec, frame_max, vhost,
+                     client_properties}).
 
 -record(content,
         {class_id,
@@ -44,6 +45,7 @@
          properties_bin, %% either 'none', or an encoded properties binary
          %% Note: at most one of properties and properties_bin can be
          %% 'none' at once.
+         protocol, %% The protocol under which properties_bin was encoded
          payload_fragments_rev %% list of binaries, in reverse order (!)
          }).
 
@@ -74,6 +76,7 @@
 
 -define(COPYRIGHT_MESSAGE, "Copyright (C) 2007-2010 LShift Ltd., Cohesive Financial Technologies LLC., and Rabbit Technologies Ltd.").
 -define(INFORMATION_MESSAGE, "Licensed under the MPL.  See http://www.rabbitmq.com/").
+-define(PROTOCOL_VERSION, "AMQP 0-9-1 / 0-9 / 0-8").
 -define(ERTS_MINIMUM, "5.6.3").
 
 -define(MAX_WAIT, 16#ffffffff).
diff --git a/src/rabbit.erl b/src/rabbit.erl
index 18045b94..ada2c38e 100644
--- a/src/rabbit.erl
+++ b/src/rabbit.erl
@@ -426,9 +426,9 @@ print_banner() ->
               "| ~s  +---+   |~n"
               "|                   |~n"
               "+-------------------+~n"
-              "AMQP ~p-~p~n~s~n~s~n~n",
+              "~s~n~s~n~s~n~n",
               [Product, string:right([$v|Version], ProductLen),
-               ?PROTOCOL_VERSION_MAJOR, ?PROTOCOL_VERSION_MINOR,
+               ?PROTOCOL_VERSION,
                ?COPYRIGHT_MESSAGE, ?INFORMATION_MESSAGE]),
     Settings = [{"node",           node()},
                 {"app descriptor", app_location()},
diff --git a/src/rabbit_amqqueue.erl b/src/rabbit_amqqueue.erl
index 6bf2f6db..870c119a 100644
--- a/src/rabbit_amqqueue.erl
+++ b/src/rabbit_amqqueue.erl
@@ -39,7 +39,7 @@
 -export([pseudo_queue/2]).
 -export([lookup/1, with/2, with_or_die/2, assert_equivalence/5,
          check_exclusive_access/2, with_exclusive_access_or_die/3,
-         stat/1, deliver/2, requeue/3, ack/4]).
+         stat/1, deliver/2, requeue/3, ack/4, reject/4]).
 -export([list/1, info_keys/0, info/1, info/2, info_all/1, info_all/2]).
 -export([consumers/1, consumers_all/1]).
 -export([basic_get/3, basic_consume/7, basic_cancel/4]).
@@ -124,6 +124,7 @@
 -spec(ack/4 ::
         (pid(), rabbit_types:maybe(rabbit_types:txn()), [msg_id()], pid())
         -> 'ok').
+-spec(reject/4 :: (pid(), [msg_id()], boolean(), pid()) -> 'ok').
 -spec(commit_all/3 :: ([pid()], rabbit_types:txn(), pid()) -> ok_or_errors()).
 -spec(rollback_all/3 :: ([pid()], rabbit_types:txn(), pid()) -> 'ok').
 -spec(notify_down_all/2 :: ([pid()], pid()) -> ok_or_errors()).
@@ -367,6 +368,9 @@ requeue(QPid, MsgIds, ChPid) ->
 ack(QPid, Txn, MsgIds, ChPid) ->
     delegate_pcast(QPid, 7, {ack, Txn, MsgIds, ChPid}).
 
+reject(QPid, MsgIds, Requeue, ChPid) ->
+    delegate_pcast(QPid, 7, {reject, MsgIds, Requeue, ChPid}).
+
 commit_all(QPids, Txn, ChPid) ->
     safe_delegate_call_ok(
       fun (QPid) -> exit({queue_disappeared, QPid}) end,
diff --git a/src/rabbit_amqqueue_process.erl b/src/rabbit_amqqueue_process.erl
index 67f0fcf5..ac5fb7f9 100644
--- a/src/rabbit_amqqueue_process.erl
+++ b/src/rabbit_amqqueue_process.erl
@@ -783,6 +783,21 @@ handle_cast({ack, Txn, AckTags, ChPid},
             noreply(State#q{backing_queue_state = BQS1})
     end;
 
+handle_cast({reject, AckTags, Requeue, ChPid},
+            State = #q{backing_queue = BQ, backing_queue_state = BQS}) ->
+    case lookup_ch(ChPid) of
+        not_found ->
+            noreply(State);
+        C = #cr{acktags = ChAckTags} ->
+            ChAckTags1 = subtract_acks(ChAckTags, AckTags),
+            store_ch_record(C#cr{acktags = ChAckTags1}),
+            noreply(case Requeue of
+                        true  -> requeue_and_run(AckTags, State);
+                        false -> BQS1 = BQ:ack(AckTags, BQS),
+                                 State #q { backing_queue_state = BQS1 }
+                    end)
+    end;
+
 handle_cast({rollback, Txn, ChPid}, State) ->
     noreply(rollback_transaction(Txn, ChPid, State));
 
diff --git a/src/rabbit_basic.erl b/src/rabbit_basic.erl
index 03a19961..c76c01ac 100644
--- a/src/rabbit_basic.erl
+++ b/src/rabbit_basic.erl
@@ -97,18 +97,24 @@ delivery(Mandatory, Immediate, Txn, Message) ->
               sender = self(), message = Message}.
 
 build_content(Properties, BodyBin) ->
-    {ClassId, _MethodId} = rabbit_framing:method_id('basic.publish'),
+    %% basic.publish hasn't changed so we can just hard-code amqp_0_9_1
+    {ClassId, _MethodId} =
+        rabbit_framing_amqp_0_9_1:method_id('basic.publish'),
     #content{class_id = ClassId,
              properties = Properties,
              properties_bin = none,
+             protocol = none,
              payload_fragments_rev = [BodyBin]}.
 
 from_content(Content) ->
     #content{class_id = ClassId,
              properties = Props,
              payload_fragments_rev = FragmentsRev} =
-        rabbit_binary_parser:ensure_content_decoded(Content),
-    {ClassId, _MethodId} = rabbit_framing:method_id('basic.publish'),
+        %% basic.publish hasn't changed so we can just hard-code amqp_0_9_1
+        rabbit_binary_parser:ensure_content_decoded(Content,
+                                                    rabbit_framing_amqp_0_9_1),
+    {ClassId, _MethodId} =
+        rabbit_framing_amqp_0_9_1:method_id('basic.publish'),
     {Props, list_to_binary(lists:reverse(FragmentsRev))}.
 
 message(ExchangeName, RoutingKeyBin, RawProperties, BodyBin) ->
diff --git a/src/rabbit_binary_generator.erl b/src/rabbit_binary_generator.erl
index 0e6ebe57..f0ec6180 100644
--- a/src/rabbit_binary_generator.erl
+++ b/src/rabbit_binary_generator.erl
@@ -41,12 +41,12 @@
 % See definition of check_empty_content_body_frame_size/0, an assertion called at startup.
 -define(EMPTY_CONTENT_BODY_FRAME_SIZE, 8).
 
--export([build_simple_method_frame/2,
-         build_simple_content_frames/3,
+-export([build_simple_method_frame/3,
+         build_simple_content_frames/4,
          build_heartbeat_frame/0]).
 -export([generate_table/1, encode_properties/2]).
 -export([check_empty_content_body_frame_size/0]).
--export([ensure_content_encoded/1, clear_encoded_content/1]).
+-export([ensure_content_encoded/2, clear_encoded_content/1]).
 
 -import(lists).
 
@@ -56,20 +56,22 @@
 
 -type(frame() :: [binary()]).
 
--spec(build_simple_method_frame/2 ::
-        (rabbit_channel:channel_number(), rabbit_framing:amqp_method_record())
+-spec(build_simple_method_frame/3 ::
+        (rabbit_channel:channel_number(), rabbit_framing:amqp_method_record(),
+         rabbit_types:protocol())
         -> frame()).
--spec(build_simple_content_frames/3 ::
+-spec(build_simple_content_frames/4 ::
         (rabbit_channel:channel_number(), rabbit_types:content(),
-         non_neg_integer())
+         non_neg_integer(), rabbit_types:protocol())
         -> [frame()]).
 -spec(build_heartbeat_frame/0 :: () -> frame()).
 -spec(generate_table/1 :: (rabbit_framing:amqp_table()) -> binary()).
 -spec(encode_properties/2 ::
         ([rabbit_framing:amqp_property_type()], [any()]) -> binary()).
 -spec(check_empty_content_body_frame_size/0 :: () -> 'ok').
--spec(ensure_content_encoded/1 ::
-        (rabbit_types:content()) -> rabbit_types:encoded_content()).
+-spec(ensure_content_encoded/2 ::
+        (rabbit_types:content(), rabbit_types:protocol()) ->
+                                       rabbit_types:encoded_content()).
 -spec(clear_encoded_content/1 ::
         (rabbit_types:content()) -> rabbit_types:unencoded_content()).
 
@@ -77,30 +79,24 @@
 
 %%----------------------------------------------------------------------------
 
-build_simple_method_frame(ChannelInt, MethodRecord) ->
-    MethodFields = rabbit_framing:encode_method_fields(MethodRecord),
+build_simple_method_frame(ChannelInt, MethodRecord, Protocol) ->
+    MethodFields = Protocol:encode_method_fields(MethodRecord),
     MethodName = rabbit_misc:method_record_type(MethodRecord),
-    {ClassId, MethodId} = rabbit_framing:method_id(MethodName),
+    {ClassId, MethodId} = Protocol:method_id(MethodName),
     create_frame(1, ChannelInt, [<<ClassId:16, MethodId:16>>, MethodFields]).
 
-build_simple_content_frames(ChannelInt,
-                            #content{class_id = ClassId,
-                                     properties = ContentProperties,
-                                     properties_bin = ContentPropertiesBin,
-                                     payload_fragments_rev = PayloadFragmentsRev},
-                            FrameMax) ->
-    {BodySize, ContentFrames} = build_content_frames(PayloadFragmentsRev, FrameMax, ChannelInt),
+build_simple_content_frames(ChannelInt, Content, FrameMax, Protocol) ->
+    #content{class_id = ClassId,
+             properties_bin = ContentPropertiesBin,
+             payload_fragments_rev = PayloadFragmentsRev} =
+        ensure_content_encoded(Content, Protocol),
+    {BodySize, ContentFrames} =
+        build_content_frames(PayloadFragmentsRev, FrameMax, ChannelInt),
     HeaderFrame = create_frame(2, ChannelInt,
                                [<<ClassId:16, 0:16, BodySize:64>>,
-                                maybe_encode_properties(ContentProperties, ContentPropertiesBin)]),
+                                ContentPropertiesBin]),
     [HeaderFrame | ContentFrames].
 
-maybe_encode_properties(_ContentProperties, ContentPropertiesBin)
-  when is_binary(ContentPropertiesBin) ->
-    ContentPropertiesBin;
-maybe_encode_properties(ContentProperties, none) ->
-    rabbit_framing:encode_properties(ContentProperties).
-
 build_content_frames(FragsRev, FrameMax, ChannelInt) ->
     BodyPayloadMax = if FrameMax == 0 ->
                              iolist_size(FragsRev);
@@ -283,13 +279,16 @@ check_empty_content_body_frame_size() ->
                   ComputedSize, ?EMPTY_CONTENT_BODY_FRAME_SIZE})
     end.
 
-ensure_content_encoded(Content = #content{properties_bin = PropsBin})
+ensure_content_encoded(Content = #content{properties_bin = PropsBin,
+                                          protocol = Protocol}, Protocol)
   when PropsBin =/= 'none' ->
     Content;
-ensure_content_encoded(Content = #content{properties = Props}) ->
-    Content #content{properties_bin = rabbit_framing:encode_properties(Props)}.
+ensure_content_encoded(Content = #content{properties = Props}, Protocol) ->
+    Content#content{properties_bin = Protocol:encode_properties(Props),
+                    protocol = Protocol}.
 
-clear_encoded_content(Content = #content{properties_bin = none}) ->
+clear_encoded_content(Content = #content{properties_bin = none,
+                                         protocol = none}) ->
     Content;
 clear_encoded_content(Content = #content{properties = none}) ->
     %% Only clear when we can rebuild the properties_bin later in
@@ -297,4 +296,4 @@ clear_encoded_content(Content = #content{properties = none}) ->
     %% one of properties and properties_bin can be 'none'
     Content;
 clear_encoded_content(Content = #content{}) ->
-    Content#content{properties_bin = none}.
+    Content#content{properties_bin = none, protocol = none}.
diff --git a/src/rabbit_binary_parser.erl b/src/rabbit_binary_parser.erl
index 69e34440..1d0a62af 100644
--- a/src/rabbit_binary_parser.erl
+++ b/src/rabbit_binary_parser.erl
@@ -34,7 +34,7 @@
 -include("rabbit.hrl").
 
 -export([parse_table/1, parse_properties/2]).
--export([ensure_content_decoded/1, clear_decoded_content/1]).
+-export([ensure_content_decoded/2, clear_decoded_content/1]).
 
 -import(lists).
 
@@ -45,8 +45,9 @@
 -spec(parse_table/1 :: (binary()) -> rabbit_framing:amqp_table()).
 -spec(parse_properties/2 ::
         ([rabbit_framing:amqp_property_type()], binary()) -> [any()]).
--spec(ensure_content_decoded/1 ::
-        (rabbit_types:content()) -> rabbit_types:decoded_content()).
+-spec(ensure_content_decoded/2 ::
+        (rabbit_types:content(), rabbit_types:protocol())
+        -> rabbit_types:decoded_content()).
 -spec(clear_decoded_content/1 ::
         (rabbit_types:content()) -> rabbit_types:undecoded_content()).
 
@@ -162,12 +163,12 @@ parse_property(bit, Rest) ->
 parse_property(table, <<Len:32/unsigned, Table:Len/binary, Rest/binary>>) ->
     {parse_table(Table), Rest}.
 
-ensure_content_decoded(Content = #content{properties = Props})
+ensure_content_decoded(Content = #content{properties = Props}, _Protocol)
   when Props =/= 'none' ->
     Content;
-ensure_content_decoded(Content = #content{properties_bin = PropBin})
+ensure_content_decoded(Content = #content{properties_bin = PropBin}, Protocol)
   when is_binary(PropBin) ->
-    Content#content{properties = rabbit_framing:decode_properties(
+    Content#content{properties = Protocol:decode_properties(
                                    Content#content.class_id, PropBin)}.
 
 clear_decoded_content(Content = #content{properties = none}) ->
diff --git a/src/rabbit_channel.erl b/src/rabbit_channel.erl
index dafc3075..1928e21d 100644
--- a/src/rabbit_channel.erl
+++ b/src/rabbit_channel.erl
@@ -36,11 +36,9 @@
 -behaviour(gen_server2).
 
 -export([start_link/6, do/2, do/3, shutdown/1]).
--export([send_command/2, deliver/4, conserve_memory/2, flushed/2]).
+-export([send_command/2, deliver/4, flushed/2]).
 -export([list/0, info_keys/0, info/1, info/2, info_all/0, info_all/1]).
 
--export([flow_timeout/2]).
-
 -export([init/1, terminate/2, code_change/3, handle_call/3, handle_cast/2,
          handle_info/2, handle_pre_hibernate/1]).
 
@@ -48,12 +46,9 @@
              transaction_id, tx_participants, next_tag,
              uncommitted_ack_q, unacked_message_q,
              username, virtual_host, most_recently_declared_queue,
-             consumer_mapping, blocking, queue_collector_pid, flow}).
-
--record(flow, {server, client, pending}).
+             consumer_mapping, blocking, queue_collector_pid}).
 
 -define(MAX_PERMISSION_CACHE_SIZE, 12).
--define(FLOW_OK_TIMEOUT, 10000). %% 10 seconds
 
 -define(INFO_KEYS,
         [pid,
@@ -78,7 +73,7 @@
 
 -spec(start_link/6 ::
       (channel_number(), pid(), pid(), rabbit_access_control:username(),
-       rabbit_types:vhost(), pid()) -> pid()).
+       rabbit_types:vhost(), pid()) -> rabbit_types:ok(pid())).
 -spec(do/2 :: (pid(), rabbit_framing:amqp_method_record()) -> 'ok').
 -spec(do/3 :: (pid(), rabbit_framing:amqp_method_record(),
                rabbit_types:maybe(rabbit_types:content())) -> 'ok').
@@ -87,9 +82,7 @@
 -spec(deliver/4 ::
         (pid(), rabbit_types:ctag(), boolean(), rabbit_amqqueue:qmsg())
         -> 'ok').
--spec(conserve_memory/2 :: (pid(), boolean()) -> 'ok').
 -spec(flushed/2 :: (pid(), pid()) -> 'ok').
--spec(flow_timeout/2 :: (pid(), ref()) -> 'ok').
 -spec(list/0 :: () -> [pid()]).
 -spec(info_keys/0 :: () -> [rabbit_types:info_key()]).
 -spec(info/1 :: (pid()) -> [rabbit_types:info()]).
@@ -102,10 +95,8 @@
 %%----------------------------------------------------------------------------
 
 start_link(Channel, ReaderPid, WriterPid, Username, VHost, CollectorPid) ->
-    {ok, Pid} = gen_server2:start_link(
-                  ?MODULE, [Channel, ReaderPid, WriterPid,
-                            Username, VHost, CollectorPid], []),
-    Pid.
+    gen_server2:start_link(?MODULE, [Channel, ReaderPid, WriterPid,
+                                     Username, VHost, CollectorPid], []).
 
 do(Pid, Method) ->
     do(Pid, Method, none).
@@ -122,15 +113,9 @@ send_command(Pid, Msg) ->
 deliver(Pid, ConsumerTag, AckRequired, Msg) ->
     gen_server2:cast(Pid, {deliver, ConsumerTag, AckRequired, Msg}).
 
-conserve_memory(Pid, Conserve) ->
-    gen_server2:pcast(Pid, 8, {conserve_memory, Conserve}).
-
 flushed(Pid, QPid) ->
     gen_server2:cast(Pid, {flushed, QPid}).
 
-flow_timeout(Pid, Ref) ->
-    gen_server2:pcast(Pid, 7, {flow_timeout, Ref}).
-
 list() ->
     pg_local:get_members(rabbit_channels).
 
@@ -172,9 +157,7 @@ init([Channel, ReaderPid, WriterPid, Username, VHost, CollectorPid]) ->
              most_recently_declared_queue = <<>>,
              consumer_mapping        = dict:new(),
              blocking                = dict:new(),
-             queue_collector_pid     = CollectorPid,
-             flow                    = #flow{server = true, client = true,
-                                             pending = none}},
+             queue_collector_pid     = CollectorPid},
      hibernate,
      {backoff, ?HIBERNATE_AFTER_MIN, ?HIBERNATE_AFTER_MIN, ?DESIRED_HIBERNATE}}.
 
@@ -225,27 +208,7 @@ handle_cast({deliver, ConsumerTag, AckRequired, Msg},
                         next_tag = DeliveryTag}) ->
     State1 = lock_message(AckRequired, {DeliveryTag, ConsumerTag, Msg}, State),
     ok = internal_deliver(WriterPid, true, ConsumerTag, DeliveryTag, Msg),
-    noreply(State1#ch{next_tag = DeliveryTag + 1});
-
-handle_cast({conserve_memory, true}, State = #ch{state = starting}) ->
-    noreply(State);
-handle_cast({conserve_memory, false}, State = #ch{state = starting}) ->
-    ok = rabbit_writer:send_command(State#ch.writer_pid, #'channel.open_ok'{}),
-    noreply(State#ch{state = running});
-handle_cast({conserve_memory, Conserve}, State = #ch{state = running}) ->
-    flow_control(not Conserve, State);
-handle_cast({conserve_memory, _Conserve}, State) ->
-    noreply(State);
-
-handle_cast({flow_timeout, Ref},
-            State = #ch{flow = #flow{client = Flow, pending = {Ref, _TRef}}}) ->
-    {stop, normal, terminating(
-                     rabbit_misc:amqp_error(
-                       precondition_failed,
-                       "timeout waiting for channel.flow_ok{active=~w}",
-                       [not Flow], none), State)};
-handle_cast({flow_timeout, _Ref}, State) ->
-    {noreply, State}.
+    noreply(State1#ch{next_tag = DeliveryTag + 1}).
 
 handle_info({'EXIT', WriterPid, Reason = {writer, send_failed, _Error}},
             State = #ch{writer_pid = WriterPid}) ->
@@ -385,10 +348,7 @@ queue_blocked(QPid, State = #ch{blocking = Blocking}) ->
     end.
 
 handle_method(#'channel.open'{}, _, State = #ch{state = starting}) ->
-    case rabbit_alarm:register(self(), {?MODULE, conserve_memory, []}) of
-        true  -> {noreply, State};
-        false -> {reply, #'channel.open_ok'{}, State#ch{state = running}}
-    end;
+    {reply, #'channel.open_ok'{}, State#ch{state = running}};
 
 handle_method(#'channel.open'{}, _, _State) ->
     rabbit_misc:protocol_error(
@@ -405,10 +365,6 @@ handle_method(#'channel.close'{}, _, State = #ch{writer_pid = WriterPid}) ->
 handle_method(#'access.request'{},_, State) ->
     {reply, #'access.request_ok'{ticket = 1}, State};
 
-handle_method(#'basic.publish'{}, _, #ch{flow = #flow{client = false}}) ->
-    rabbit_misc:protocol_error(
-      command_invalid,
-      "basic.publish received after channel.flow_ok{active=false}", []);
 handle_method(#'basic.publish'{exchange    = ExchangeNameBin,
                                routing_key = RoutingKey,
                                mandatory   = Mandatory,
@@ -421,7 +377,8 @@ handle_method(#'basic.publish'{exchange    = ExchangeNameBin,
     Exchange = rabbit_exchange:lookup_or_die(ExchangeName),
     %% We decode the content's properties here because we're almost
     %% certain to want to look at delivery-mode and priority.
-    DecodedContent = rabbit_binary_parser:ensure_content_decoded(Content),
+    DecodedContent = rabbit_binary_parser:ensure_content_decoded(
+                       Content, rabbit_framing_amqp_0_9_1),
     IsPersistent = is_message_persistent(DecodedContent),
     Message = #basic_message{exchange_name  = ExchangeName,
                              routing_key    = RoutingKey,
@@ -638,6 +595,17 @@ handle_method(#'basic.recover'{requeue = Requeue}, Content, State) ->
     ok = rabbit_writer:send_command(WriterPid, #'basic.recover_ok'{}),
     {noreply, State2};
 
+handle_method(#'basic.reject'{delivery_tag = DeliveryTag,
+                              requeue = Requeue},
+              _, State = #ch{ unacked_message_q = UAMQ}) ->
+    {Acked, Remaining} = collect_acks(UAMQ, DeliveryTag, false),
+    ok = fold_per_queue(
+           fun (QPid, MsgIds, ok) ->
+                   rabbit_amqqueue:reject(QPid, MsgIds, Requeue, self())
+           end, ok, Acked),
+    ok = notify_limiter(State#ch.limiter_pid, Acked),
+    {noreply, State#ch{unacked_message_q = Remaining}};
+
 handle_method(#'exchange.declare'{exchange = ExchangeNameBin,
                                   type = TypeNameBin,
                                   passive = false,
@@ -853,48 +821,12 @@ handle_method(#'channel.flow'{active = false}, _,
                                  blocking = dict:from_list(Queues)}}
     end;
 
-handle_method(#'channel.flow_ok'{active = Active}, _,
-              State = #ch{flow = #flow{server = Active, client = Flow,
-                                       pending = {_Ref, TRef}} = F})
-  when Flow =:= not Active ->
-    {ok, cancel} = timer:cancel(TRef),
-    {noreply, State#ch{flow = F#flow{client = Active, pending = none}}};
-handle_method(#'channel.flow_ok'{active = Active}, _,
-              State = #ch{flow = #flow{server = Flow, client = Flow,
-                                       pending = {_Ref, TRef}}})
-  when Flow =:= not Active ->
-    {ok, cancel} = timer:cancel(TRef),
-    {noreply, issue_flow(Flow, State)};
-handle_method(#'channel.flow_ok'{}, _, #ch{flow = #flow{pending = none}}) ->
-    rabbit_misc:protocol_error(
-      command_invalid, "unsolicited channel.flow_ok", []);
-handle_method(#'channel.flow_ok'{active = Active}, _, _State) ->
-    rabbit_misc:protocol_error(
-      command_invalid,
-      "received channel.flow_ok{active=~w} has incorrect polarity", [Active]);
-
 handle_method(_MethodRecord, _Content, _State) ->
     rabbit_misc:protocol_error(
       command_invalid, "unimplemented method", []).
 
 %%----------------------------------------------------------------------------
 
-flow_control(Active, State = #ch{flow = #flow{server = Flow, pending = none}})
-  when Flow =:= not Active ->
-    ok = clear_permission_cache(),
-    noreply(issue_flow(Active, State));
-flow_control(Active, State = #ch{flow = F}) ->
-    noreply(State#ch{flow = F#flow{server = Active}}).
-
-issue_flow(Active, State) ->
-    ok = rabbit_writer:send_command(
-           State#ch.writer_pid, #'channel.flow'{active = Active}),
-    Ref = make_ref(),
-    {ok, TRef} = timer:apply_after(?FLOW_OK_TIMEOUT, ?MODULE, flow_timeout,
-                                   [self(), Ref]),
-    State#ch{flow = #flow{server = Active, client = not Active,
-                          pending = {Ref, TRef}}}.
-
 binding_action(Fun, ExchangeNameBin, QueueNameBin, RoutingKey, Arguments,
                ReturnMethod, NoWait,
                State = #ch{virtual_host = VHostPath,
@@ -938,7 +870,7 @@ basic_return(#basic_message{exchange_name = ExchangeName,
                             content       = Content},
              WriterPid, Reason) ->
     {_Close, ReplyCode, ReplyText} =
-        rabbit_framing:lookup_amqp_exception(Reason),
+        rabbit_framing_amqp_0_9_1:lookup_amqp_exception(Reason),
     ok = rabbit_writer:send_command(
            WriterPid,
            #'basic.return'{reply_code  = ReplyCode,
@@ -1031,7 +963,7 @@ fold_per_queue(F, Acc0, UAQ) ->
               Acc0, D).
 
 start_limiter(State = #ch{unacked_message_q = UAMQ}) ->
-    LPid = rabbit_limiter:start_link(self(), queue:len(UAMQ)),
+    {ok, LPid} = rabbit_limiter:start_link(self(), queue:len(UAMQ)),
     ok = limit_queues(LPid, State),
     LPid.
 
diff --git a/src/rabbit_exchange.erl b/src/rabbit_exchange.erl
index 7f7622b2..49f87a22 100644
--- a/src/rabbit_exchange.erl
+++ b/src/rabbit_exchange.erl
@@ -378,7 +378,6 @@ cleanup_deleted_queue_bindings1(ExchangeName, Bindings) ->
     [X] = mnesia:read({rabbit_exchange, ExchangeName}),
     {maybe_auto_delete(X), Bindings}.
 
-
 delete_forward_routes(Route) ->
     ok = mnesia:delete_object(rabbit_route, Route, write),
     ok = mnesia:delete_object(rabbit_durable_route, Route, write).
diff --git a/src/rabbit_framing_channel.erl b/src/rabbit_framing_channel.erl
index bc1a2a08..00b74ad0 100644
--- a/src/rabbit_framing_channel.erl
+++ b/src/rabbit_framing_channel.erl
@@ -32,21 +32,22 @@
 -module(rabbit_framing_channel).
 -include("rabbit.hrl").
 
--export([start_link/2, process/2, shutdown/1]).
+-export([start_link/3, process/2, shutdown/1]).
 
 %% internal
--export([mainloop/1]).
+-export([mainloop/2]).
 
 %%--------------------------------------------------------------------
 
-start_link(StartFun, StartArgs) ->
-    spawn_link(
-      fun () ->
-              %% we trap exits so that a normal termination of the
-              %% channel or reader process terminates us too.
-              process_flag(trap_exit, true),
-              mainloop(apply(StartFun, StartArgs))
-      end).
+start_link(StartFun, StartArgs, Protocol) ->
+    {ok, spawn_link(
+           fun () ->
+                   %% we trap exits so that a normal termination of
+                   %% the channel or reader process terminates us too.
+                   process_flag(trap_exit, true),
+                   {ok, ChannelPid} = apply(StartFun, StartArgs),
+                   mainloop(ChannelPid, Protocol)
+           end)}.
 
 process(Pid, Frame) ->
     Pid ! {frame, Frame},
@@ -72,37 +73,42 @@ read_frame(ChannelPid) ->
         Msg                    -> exit({unexpected_message, Msg})
     end.
 
-mainloop(ChannelPid) ->
-    {method, MethodName, FieldsBin} = read_frame(ChannelPid),
-    Method = rabbit_framing:decode_method_fields(MethodName, FieldsBin),
-    case rabbit_framing:method_has_content(MethodName) of
-        true  -> {ClassId, _MethodId} = rabbit_framing:method_id(MethodName),
-                 rabbit_channel:do(ChannelPid, Method,
-                                   collect_content(ChannelPid, ClassId));
-        false -> rabbit_channel:do(ChannelPid, Method)
-    end,
-    ?MODULE:mainloop(ChannelPid).
+mainloop(ChannelPid, Protocol) ->
+    case read_frame(ChannelPid) of
+        {method, MethodName, FieldsBin} ->
+            Method = Protocol:decode_method_fields(MethodName, FieldsBin),
+            case Protocol:method_has_content(MethodName) of
+                true  -> {ClassId, _MethodId} = Protocol:method_id(MethodName),
+                         rabbit_channel:do(ChannelPid, Method,
+                                           collect_content(ChannelPid,
+                                                           ClassId,
+                                                           Protocol));
+                false -> rabbit_channel:do(ChannelPid, Method)
+            end,
+            ?MODULE:mainloop(ChannelPid, Protocol);
+        _ ->
+            unexpected_frame("expected method frame, "
+                             "got non method frame instead",
+                             [])
+    end.
 
-collect_content(ChannelPid, ClassId) ->
+collect_content(ChannelPid, ClassId, Protocol) ->
     case read_frame(ChannelPid) of
         {content_header, ClassId, 0, BodySize, PropertiesBin} ->
             Payload = collect_content_payload(ChannelPid, BodySize, []),
             #content{class_id = ClassId,
                      properties = none,
                      properties_bin = PropertiesBin,
+                     protocol = Protocol,
                      payload_fragments_rev = Payload};
         {content_header, HeaderClassId, 0, _BodySize, _PropertiesBin} ->
-            rabbit_misc:protocol_error(
-              command_invalid,
-              "expected content header for class ~w, "
-              "got one for class ~w instead",
-              [ClassId, HeaderClassId]);
+            unexpected_frame("expected content header for class ~w, "
+                             "got one for class ~w instead",
+                             [ClassId, HeaderClassId]);
         _ ->
-            rabbit_misc:protocol_error(
-              command_invalid,
-              "expected content header for class ~w, "
-              "got non content header frame instead",
-              [ClassId])
+            unexpected_frame("expected content header for class ~w, "
+                             "got non content header frame instead",
+                             [ClassId])
     end.
 
 collect_content_payload(_ChannelPid, 0, Acc) ->
@@ -114,8 +120,10 @@ collect_content_payload(ChannelPid, RemainingByteCount, Acc) ->
                                     RemainingByteCount - size(FragmentBin),
                                     [FragmentBin | Acc]);
         _ ->
-            rabbit_misc:protocol_error(
-              command_invalid,
-              "expected content body, got non content body frame instead",
-              [])
+            unexpected_frame("expected content body, "
+                             "got non content body frame instead",
+                             [])
     end.
+
+unexpected_frame(ExplanationFormat, Params) ->
+    rabbit_misc:protocol_error(unexpected_frame, ExplanationFormat, Params).
diff --git a/src/rabbit_limiter.erl b/src/rabbit_limiter.erl
index 878af029..813ccc75 100644
--- a/src/rabbit_limiter.erl
+++ b/src/rabbit_limiter.erl
@@ -45,7 +45,7 @@
 
 -type(maybe_pid() :: pid() | 'undefined').
 
--spec(start_link/2 :: (pid(), non_neg_integer()) -> pid()).
+-spec(start_link/2 :: (pid(), non_neg_integer()) -> rabbit_types:ok(pid())).
 -spec(shutdown/1 :: (maybe_pid()) -> 'ok').
 -spec(limit/2 :: (maybe_pid(), non_neg_integer()) -> 'ok' | 'stopped').
 -spec(can_send/3 :: (maybe_pid(), pid(), boolean()) -> boolean()).
@@ -74,8 +74,7 @@
 %%----------------------------------------------------------------------------
 
 start_link(ChPid, UnackedMsgCount) ->
-    {ok, Pid} = gen_server2:start_link(?MODULE, [ChPid, UnackedMsgCount], []),
-    Pid.
+    gen_server2:start_link(?MODULE, [ChPid, UnackedMsgCount], []).
 
 shutdown(undefined) ->
     ok;
diff --git a/src/rabbit_reader.erl b/src/rabbit_reader.erl
index b5514c82..46171aec 100644
--- a/src/rabbit_reader.erl
+++ b/src/rabbit_reader.erl
@@ -39,9 +39,9 @@
 
 -export([init/1, mainloop/3]).
 
--export([server_properties/0]).
+-export([conserve_memory/2, server_properties/0]).
 
--export([analyze_frame/2]).
+-export([analyze_frame/3]).
 
 -import(gen_tcp).
 -import(fprof).
@@ -58,12 +58,12 @@
 %---------------------------------------------------------------------------
 
 -record(v1, {sock, connection, callback, recv_ref, connection_state,
-             queue_collector}).
+             queue_collector, conserving_memory}).
 
 -define(INFO_KEYS,
         [pid, address, port, peer_address, peer_port,
-         recv_oct, recv_cnt, send_oct, send_cnt, send_pend,
-         state, channels, user, vhost, timeout, frame_max, client_properties]).
+         recv_oct, recv_cnt, send_oct, send_cnt, send_pend, state, channels,
+         protocol, user, vhost, timeout, frame_max, client_properties]).
 
 %% connection lifecycle
 %%
@@ -142,6 +142,7 @@
 -spec(info/1 :: (pid()) -> [rabbit_types:info()]).
 -spec(info/2 :: (pid(), [rabbit_types:info_key()]) -> [rabbit_types:info()]).
 -spec(shutdown/2 :: (pid(), string()) -> 'ok').
+-spec(conserve_memory/2 :: (pid(), boolean()) -> 'ok').
 -spec(server_properties/0 :: () -> rabbit_framing:amqp_table()).
 
 -endif.
@@ -208,6 +209,10 @@ teardown_profiling(Value) ->
             fprof:analyse([{dest, []}, {cols, 100}])
     end.
 
+conserve_memory(Pid, Conserve) ->
+    Pid ! {conserve_memory, Conserve},
+    ok.
+
 server_properties() ->
     {ok, Product} = application:get_key(rabbit, id),
     {ok, Version} = application:get_key(rabbit, vsn),
@@ -249,7 +254,8 @@ start_connection(Parent, Deb, Sock, SockTransform) ->
                                       timeout_sec = ?HANDSHAKE_TIMEOUT,
                                       frame_max = ?FRAME_MIN_SIZE,
                                       vhost = none,
-                                      client_properties = none},
+                                      client_properties = none,
+                                      protocol = none},
                                     callback = uninitialized_callback,
                                     recv_ref = none,
                                     connection_state = pre_init,
@@ -294,6 +300,8 @@ mainloop(Parent, Deb, State = #v1{sock= Sock, recv_ref = Ref}) ->
             end;
         {inet_async, Sock, Ref, {error, Reason}} ->
             throw({inet_error, Reason});
+        {conserve_memory, Conserve} ->
+            mainloop(Parent, Deb, internal_conserve_memory(Conserve, State));
         {'EXIT', Parent, Reason} ->
             terminate(io_lib:format("broker forced connection closure "
                                     "with reason '~w'", [Reason]), State),
@@ -347,11 +355,14 @@ mainloop(Parent, Deb, State = #v1{sock= Sock, recv_ref = Ref}) ->
             exit({unexpected_message, Other})
     end.
 
-switch_callback(OldState, NewCallback, Length) ->
+switch_callback(State = #v1{conserving_memory = true}, Callback, Length) ->
+    %% TODO: pause heartbeat monitor
+    %% TODO: only do this after receiving a content-bearing method
+    State#v1{callback = {Callback, Length}, recv_ref = none};
+switch_callback(State, Callback, Length) ->
     Ref = inet_op(fun () -> rabbit_net:async_recv(
-                              OldState#v1.sock, Length, infinity) end),
-    OldState#v1{callback = NewCallback,
-                recv_ref = Ref}.
+                              State#v1.sock, Length, infinity) end),
+    State#v1{callback = Callback, recv_ref = Ref}.
 
 terminate(Explanation, State = #v1{connection_state = running}) ->
     {normal, send_exception(State, 0,
@@ -360,6 +371,14 @@ terminate(Explanation, State = #v1{connection_state = running}) ->
 terminate(_Explanation, State) ->
     {force, State}.
 
+internal_conserve_memory(false, State = #v1{conserving_memory = true,
+                                            callback = {Callback, Length},
+                                            recv_ref = none}) ->
+    %% TODO: resume heartbeat monitor
+    switch_callback(State#v1{conserving_memory = false}, Callback, Length);
+internal_conserve_memory(Conserve, State) ->
+    State#v1{conserving_memory = Conserve}.
+
 close_connection(State = #v1{connection = #connection{
                                timeout_sec = TimeoutSec}}) ->
     %% We terminate the connection after the specified interval, but
@@ -437,7 +456,9 @@ wait_for_channel_termination(N, TimerRef) ->
     end.
 
 maybe_close(State = #v1{connection_state = closing,
-                        queue_collector = Collector}) ->
+                        queue_collector = Collector,
+                        connection = #connection{protocol = Protocol},
+                        sock = Sock}) ->
     case all_channels() of
         [] ->
             %% Spec says "Exclusive queues may only be accessed by the current
@@ -445,16 +466,18 @@ maybe_close(State = #v1{connection_state = closing,
             %% This does not strictly imply synchrony, but in practice it seems
             %% to be what people assume.
             rabbit_queue_collector:delete_all(Collector),
-            ok = send_on_channel0(State#v1.sock, #'connection.close_ok'{}),
+            ok = send_on_channel0(Sock, #'connection.close_ok'{}, Protocol),
             close_connection(State);
         _  -> State
     end;
 maybe_close(State) ->
     State.
 
-handle_frame(Type, 0, Payload, State = #v1{connection_state = CS})
+handle_frame(Type, 0, Payload,
+             State = #v1{connection_state = CS,
+                         connection = #connection{protocol = Protocol}})
   when CS =:= closing; CS =:= closed ->
-    case analyze_frame(Type, Payload) of
+    case analyze_frame(Type, Payload, Protocol) of
         {method, MethodName, FieldsBin} ->
             handle_method0(MethodName, FieldsBin, State);
         _Other -> State
@@ -462,20 +485,20 @@ handle_frame(Type, 0, Payload, State = #v1{connection_state = CS})
 handle_frame(_Type, _Channel, _Payload, State = #v1{connection_state = CS})
   when CS =:= closing; CS =:= closed ->
     State;
-handle_frame(Type, 0, Payload, State) ->
-    case analyze_frame(Type, Payload) of
+handle_frame(Type, 0, Payload,
+             State = #v1{connection = #connection{protocol = Protocol}}) ->
+    case analyze_frame(Type, Payload, Protocol) of
         error     -> throw({unknown_frame, 0, Type, Payload});
         heartbeat -> State;
-        trace     -> State;
         {method, MethodName, FieldsBin} ->
             handle_method0(MethodName, FieldsBin, State);
         Other -> throw({unexpected_frame_on_channel0, Other})
     end;
-handle_frame(Type, Channel, Payload, State) ->
-    case analyze_frame(Type, Payload) of
+handle_frame(Type, Channel, Payload,
+             State = #v1{connection = #connection{protocol = Protocol}}) ->
+    case analyze_frame(Type, Payload, Protocol) of
         error         -> throw({unknown_frame, Channel, Type, Payload});
         heartbeat     -> throw({unexpected_heartbeat_frame, Channel});
-        trace         -> throw({unexpected_trace_frame, Channel});
         AnalyzedFrame ->
             %%?LOGDEBUG("Ch ~p Frame ~p~n", [Channel, AnalyzedFrame]),
             case get({channel, Channel}) of
@@ -516,17 +539,20 @@ handle_frame(Type, Channel, Payload, State) ->
             end
     end.
 
-analyze_frame(?FRAME_METHOD, <<ClassId:16, MethodId:16, MethodFields/binary>>) ->
-    {method, rabbit_framing:lookup_method_name({ClassId, MethodId}), MethodFields};
-analyze_frame(?FRAME_HEADER, <<ClassId:16, Weight:16, BodySize:64, Properties/binary>>) ->
+analyze_frame(?FRAME_METHOD,
+              <<ClassId:16, MethodId:16, MethodFields/binary>>,
+              Protocol) ->
+    MethodName = Protocol:lookup_method_name({ClassId, MethodId}),
+    {method, MethodName, MethodFields};
+analyze_frame(?FRAME_HEADER,
+              <<ClassId:16, Weight:16, BodySize:64, Properties/binary>>,
+              _Protocol) ->
     {content_header, ClassId, Weight, BodySize, Properties};
-analyze_frame(?FRAME_BODY, Body) ->
+analyze_frame(?FRAME_BODY, Body, _Protocol) ->
     {content_body, Body};
-analyze_frame(?FRAME_TRACE, _Body) ->
-    trace;
-analyze_frame(?FRAME_HEARTBEAT, <<>>) ->
+analyze_frame(?FRAME_HEARTBEAT, <<>>, _Protocol) ->
     heartbeat;
-analyze_frame(_Type, _Body) ->
+analyze_frame(_Type, _Body, _Protocol) ->
     error.
 
 handle_input(frame_header, <<Type:8,Channel:16,PayloadSize:32>>, State) ->
@@ -543,54 +569,61 @@ handle_input({frame_payload, Type, Channel, PayloadSize}, PayloadAndMarker, Stat
             throw({bad_payload, PayloadAndMarker})
     end;
 
-handle_input(handshake, <<"AMQP",1,1,ProtocolMajor,ProtocolMinor>>,
-             State = #v1{sock = Sock, connection = Connection}) ->
-    case check_version({ProtocolMajor, ProtocolMinor},
-                       {?PROTOCOL_VERSION_MAJOR, ?PROTOCOL_VERSION_MINOR}) of
-        true ->
-            ok = send_on_channel0(
-                   Sock,
-                   #'connection.start'{
-                     version_major = ?PROTOCOL_VERSION_MAJOR,
-                     version_minor = ?PROTOCOL_VERSION_MINOR,
-                     server_properties = server_properties(),
-                     mechanisms = <<"PLAIN AMQPLAIN">>,
-                     locales = <<"en_US">> }),
-            {State#v1{connection = Connection#connection{
-                                     timeout_sec = ?NORMAL_TIMEOUT},
-                      connection_state = starting},
-             frame_header, 7};
-        false ->
-            throw({bad_version, ProtocolMajor, ProtocolMinor})
-    end;
+%% The two rules pertaining to version negotiation:
+%%
+%% * If the server cannot support the protocol specified in the
+%% protocol header, it MUST respond with a valid protocol header and
+%% then close the socket connection.
+%%
+%% * The server MUST provide a protocol version that is lower than or
+%% equal to that requested by the client in the protocol header.
+handle_input(handshake, <<"AMQP", 0, 0, 9, 1>>, State) ->
+    start_connection({0, 9, 1}, rabbit_framing_amqp_0_9_1, State);
+
+handle_input(handshake, <<"AMQP", 1, 1, 0, 9>>, State) ->
+    start_connection({0, 9, 0}, rabbit_framing_amqp_0_9_1, State);
+
+%% the 0-8 spec, confusingly, defines the version as 8-0
+handle_input(handshake, <<"AMQP", 1, 1, 8, 0>>, State) ->
+    start_connection({8, 0, 0}, rabbit_framing_amqp_0_8, State);
+
+handle_input(handshake, <<"AMQP", A, B, C, D>>, #v1{sock = Sock}) ->
+    refuse_connection(Sock, {bad_version, A, B, C, D});
 
 handle_input(handshake, Other, #v1{sock = Sock}) ->
-    ok = inet_op(fun () -> rabbit_net:send(
-                             Sock, <<"AMQP",1,1,
-                                    ?PROTOCOL_VERSION_MAJOR,
-                                    ?PROTOCOL_VERSION_MINOR>>) end),
-    throw({bad_header, Other});
+    refuse_connection(Sock, {bad_header, Other});
 
 handle_input(Callback, Data, _State) ->
     throw({bad_input, Callback, Data}).
 
-%% the 0-8 spec, confusingly, defines the version as 8-0
-adjust_version({8,0})   -> {0,8};
-adjust_version(Version) -> Version.
-check_version(ClientVersion, ServerVersion) ->
-    {ClientMajor, ClientMinor} = adjust_version(ClientVersion),
-    {ServerMajor, ServerMinor} = adjust_version(ServerVersion),
-    ClientMajor > ServerMajor
-        orelse
-          (ClientMajor == ServerMajor andalso
-           ClientMinor >= ServerMinor).
+%% Offer a protocol version to the client.  Connection.start only
+%% includes a major and minor version number, Luckily 0-9 and 0-9-1
+%% are similar enough that clients will be happy with either.
+start_connection({ProtocolMajor, ProtocolMinor, _ProtocolRevision},
+                 Protocol,
+                 State = #v1{sock = Sock, connection = Connection}) ->
+    Start = #'connection.start'{ version_major = ProtocolMajor,
+                                 version_minor = ProtocolMinor,
+                                 server_properties = server_properties(),
+                                 mechanisms = <<"PLAIN AMQPLAIN">>,
+                                 locales = <<"en_US">> },
+    ok = send_on_channel0(Sock, Start, Protocol),
+    {State#v1{connection = Connection#connection{
+                             timeout_sec = ?NORMAL_TIMEOUT,
+                             protocol = Protocol},
+              connection_state = starting},
+     frame_header, 7}.
+
+refuse_connection(Sock, Exception) ->
+    ok = inet_op(fun () -> rabbit_net:send(Sock, <<"AMQP",0,0,9,1>>) end),
+    throw(Exception).
 
 %%--------------------------------------------------------------------------
 
-handle_method0(MethodName, FieldsBin, State) ->
+handle_method0(MethodName, FieldsBin,
+               State = #v1{connection = #connection{protocol = Protocol}}) ->
     try
-        handle_method0(rabbit_framing:decode_method_fields(
-                         MethodName, FieldsBin),
+        handle_method0(Protocol:decode_method_fields(MethodName, FieldsBin),
                        State)
     catch exit:Reason ->
             CompleteReason = case Reason of
@@ -612,14 +645,14 @@ handle_method0(#'connection.start_ok'{mechanism = Mechanism,
                                       response = Response,
                                       client_properties = ClientProperties},
                State = #v1{connection_state = starting,
-                           connection = Connection,
+                           connection = Connection =
+                               #connection{protocol = Protocol},
                            sock = Sock}) ->
     User = rabbit_access_control:check_login(Mechanism, Response),
-    ok = send_on_channel0(
-           Sock,
-           #'connection.tune'{channel_max = 0,
+    Tune = #'connection.tune'{channel_max = 0,
                               frame_max = ?FRAME_MAX,
-                              heartbeat = 0}),
+                              heartbeat = 0},
+    ok = send_on_channel0(Sock, Tune, Protocol),
     State#v1{connection_state = tuning,
              connection = Connection#connection{
                             user = User,
@@ -645,46 +678,31 @@ handle_method0(#'connection.tune_ok'{frame_max = FrameMax,
                                     frame_max = FrameMax}}
     end;
 
-handle_method0(#'connection.open'{virtual_host = VHostPath,
-                                  insist = Insist},
+handle_method0(#'connection.open'{virtual_host = VHostPath},
+
                State = #v1{connection_state = opening,
                            connection = Connection = #connection{
-                                          user = User},
+                                          user = User,
+                                          protocol = Protocol},
                            sock = Sock}) ->
     ok = rabbit_access_control:check_vhost_access(User, VHostPath),
     NewConnection = Connection#connection{vhost = VHostPath},
-    KnownHosts = format_listeners(rabbit_networking:active_listeners()),
-    Redirects = compute_redirects(Insist),
-    if Redirects == [] ->
-            ok = send_on_channel0(
-                   Sock,
-                   #'connection.open_ok'{known_hosts = KnownHosts}),
-            State#v1{connection_state = running,
-                     connection = NewConnection};
-       true ->
-            %% FIXME: 'host' is supposed to only contain one
-            %% address; but which one do we pick? This is
-            %% really a problem with the spec.
-            Host = format_listeners(Redirects),
-            rabbit_log:info("connection ~p redirecting to ~p~n",
-                            [self(), Host]),
-            ok = send_on_channel0(
-                   Sock,
-                   #'connection.redirect'{host = Host,
-                                          known_hosts = KnownHosts}),
-            close_connection(State#v1{connection = NewConnection})
-    end;
+    ok = send_on_channel0(Sock, #'connection.open_ok'{}, Protocol),
+    rabbit_alarm:register(self(), {?MODULE, conserve_memory, []}),
+    State#v1{connection_state = running,
+             connection = NewConnection};
 handle_method0(#'connection.close'{},
                State = #v1{connection_state = running}) ->
     lists:foreach(fun rabbit_framing_channel:shutdown/1, all_channels()),
     maybe_close(State#v1{connection_state = closing});
 handle_method0(#'connection.close'{},
                State = #v1{connection_state = CS,
+                           connection = #connection{protocol = Protocol},
                            sock = Sock})
   when CS =:= closing; CS =:= closed ->
     %% We're already closed or closing, so we don't need to cleanup
     %% anything.
-    ok = send_on_channel0(Sock, #'connection.close_ok'{}),
+    ok = send_on_channel0(Sock, #'connection.close_ok'{}, Protocol),
     State;
 handle_method0(#'connection.close_ok'{},
                State = #v1{connection_state = closed}) ->
@@ -697,23 +715,8 @@ handle_method0(_Method, #v1{connection_state = S}) ->
     rabbit_misc:protocol_error(
       channel_error, "unexpected method in connection state ~w", [S]).
 
-send_on_channel0(Sock, Method) ->
-    ok = rabbit_writer:internal_send_command(Sock, 0, Method).
-
-format_listeners(Listeners) ->
-    list_to_binary(
-      rabbit_misc:intersperse(
-        $,,
-        [io_lib:format("~s:~w", [Host, Port]) ||
-            #listener{host = Host, port = Port} <- Listeners])).
-
-compute_redirects(true) -> [];
-compute_redirects(false) ->
-    Node = node(),
-    LNode = rabbit_load:pick(),
-    if Node == LNode -> [];
-       true -> rabbit_networking:node_listeners(LNode)
-    end.
+send_on_channel0(Sock, Method, Protocol) ->
+    ok = rabbit_writer:internal_send_command(Sock, 0, Method, Protocol).
 
 %%--------------------------------------------------------------------------
 
@@ -747,6 +750,10 @@ i(state, #v1{connection_state = S}) ->
     S;
 i(channels, #v1{}) ->
     length(all_channels());
+i(protocol, #v1{connection = #connection{protocol = none}}) ->
+    none;
+i(protocol, #v1{connection = #connection{protocol = Protocol}}) ->
+    Protocol:version();
 i(user, #v1{connection = #connection{user = #user{username = Username}}}) ->
     Username;
 i(user, #v1{connection = #connection{user = none}}) ->
@@ -770,11 +777,13 @@ send_to_new_channel(Channel, AnalyzedFrame,
     #v1{sock = Sock, connection = #connection{
                        frame_max = FrameMax,
                        user = #user{username = Username},
-                       vhost = VHost}} = State,
-    WriterPid = rabbit_writer:start(Sock, Channel, FrameMax),
-    ChPid = rabbit_framing_channel:start_link(
-              fun rabbit_channel:start_link/6,
-              [Channel, self(), WriterPid, Username, VHost, Collector]),
+                       vhost = VHost,
+                       protocol = Protocol}} = State,
+    {ok, WriterPid} = rabbit_writer:start(Sock, Channel, FrameMax, Protocol),
+    {ok, ChPid} = rabbit_framing_channel:start_link(
+                    fun rabbit_channel:start_link/6,
+                    [Channel, self(), WriterPid, Username, VHost, Collector],
+                    Protocol),
     put({channel, Channel}, {chpid, ChPid}),
     put({chpid, ChPid}, {channel, Channel}),
     ok = rabbit_framing_channel:process(ChPid, AnalyzedFrame).
@@ -790,25 +799,27 @@ handle_exception(State = #v1{connection_state = CS}, Channel, Reason) ->
     log_channel_error(CS, Channel, Reason),
     send_exception(State, Channel, Reason).
 
-send_exception(State, Channel, Reason) ->
-    {ShouldClose, CloseChannel, CloseMethod} = map_exception(Channel, Reason),
+send_exception(State = #v1{connection = #connection{protocol = Protocol}},
+               Channel, Reason) ->
+    {ShouldClose, CloseChannel, CloseMethod} =
+        map_exception(Channel, Reason, Protocol),
     NewState = case ShouldClose of
                    true  -> terminate_channels(),
                             close_connection(State);
                    false -> close_channel(Channel, State)
                end,
     ok = rabbit_writer:internal_send_command(
-           NewState#v1.sock, CloseChannel, CloseMethod),
+           NewState#v1.sock, CloseChannel, CloseMethod, Protocol),
     NewState.
 
-map_exception(Channel, Reason) ->
+map_exception(Channel, Reason, Protocol) ->
     {SuggestedClose, ReplyCode, ReplyText, FailedMethod} =
-        lookup_amqp_exception(Reason),
+        lookup_amqp_exception(Reason, Protocol),
     ShouldClose = SuggestedClose or (Channel == 0),
     {ClassId, MethodId} = case FailedMethod of
                               {_, _} -> FailedMethod;
                               none   -> {0, 0};
-                              _      -> rabbit_framing:method_id(FailedMethod)
+                              _      -> Protocol:method_id(FailedMethod)
                           end,
     {CloseChannel, CloseMethod} =
         case ShouldClose of
@@ -823,22 +834,16 @@ map_exception(Channel, Reason) ->
         end,
     {ShouldClose, CloseChannel, CloseMethod}.
 
-%% FIXME: this clause can go when we move to AMQP spec >=8.1
-lookup_amqp_exception(#amqp_error{name        = precondition_failed,
-                                  explanation = Expl,
-                                  method      = Method}) ->
-    ExplBin = amqp_exception_explanation(<<"PRECONDITION_FAILED">>, Expl),
-    {false, 406, ExplBin, Method};
 lookup_amqp_exception(#amqp_error{name        = Name,
                                   explanation = Expl,
-                                  method      = Method}) ->
-    {ShouldClose, Code, Text} = rabbit_framing:lookup_amqp_exception(Name),
+                                  method      = Method},
+                      Protocol) ->
+    {ShouldClose, Code, Text} = Protocol:lookup_amqp_exception(Name),
     ExplBin = amqp_exception_explanation(Text, Expl),
     {ShouldClose, Code, ExplBin, Method};
-lookup_amqp_exception(Other) ->
+lookup_amqp_exception(Other, Protocol) ->
     rabbit_log:warning("Non-AMQP exit reason '~p'~n", [Other]),
-    {ShouldClose, Code, Text} =
-        rabbit_framing:lookup_amqp_exception(internal_error),
+    {ShouldClose, Code, Text} = Protocol:lookup_amqp_exception(internal_error),
     {ShouldClose, Code, Text, none}.
 
 amqp_exception_explanation(Text, Expl) ->
diff --git a/src/rabbit_tests.erl b/src/rabbit_tests.erl
index 090c714b..56aca1d6 100644
--- a/src/rabbit_tests.erl
+++ b/src/rabbit_tests.erl
@@ -504,8 +504,10 @@ test_content_framing(FrameMax, BodyBin) ->
         rabbit_binary_generator:build_simple_content_frames(
           1,
           rabbit_binary_generator:ensure_content_encoded(
-            rabbit_basic:build_content(#'P_basic'{}, BodyBin)),
-          FrameMax),
+            rabbit_basic:build_content(#'P_basic'{}, BodyBin),
+            rabbit_framing_amqp_0_9_1),
+          FrameMax,
+          rabbit_framing_amqp_0_9_1),
     %% header is formatted correctly and the size is the total of the
     %% fragments
     <<_FrameHeader:7/binary, _ClassAndWeight:4/binary,
@@ -938,8 +940,8 @@ test_user_management() ->
 test_server_status() ->
     %% create a few things so there is some useful information to list
     Writer = spawn(fun () -> receive shutdown -> ok end end),
-    Ch = rabbit_channel:start_link(1, self(), Writer, <<"user">>, <<"/">>,
-                                   self()),
+    {ok, Ch} = rabbit_channel:start_link(1, self(), Writer,
+                                         <<"user">>, <<"/">>, self()),
     [Q, Q2] = [Queue || Name <- [<<"foo">>, <<"bar">>],
                         {new, Queue = #amqqueue{}} <-
                             [rabbit_amqqueue:declare(
@@ -1068,8 +1070,8 @@ test_memory_pressure_sync(Ch, Writer) ->
 test_memory_pressure_spawn() ->
     Me = self(),
     Writer = spawn(fun () -> test_memory_pressure_receiver(Me) end),
-    Ch = rabbit_channel:start_link(1, self(), Writer, <<"user">>, <<"/">>,
-                                   self()),
+    {ok, Ch} = rabbit_channel:start_link(1, self(), Writer,
+                                         <<"user">>, <<"/">>, self()),
     ok = rabbit_channel:do(Ch, #'channel.open'{}),
     MRef = erlang:monitor(process, Ch),
     receive #'channel.open_ok'{} -> ok
@@ -1142,8 +1144,8 @@ test_memory_pressure() ->
     alarm_handler:set_alarm({vm_memory_high_watermark, []}),
     Me = self(),
     Writer4 = spawn(fun () -> test_memory_pressure_receiver(Me) end),
-    Ch4 = rabbit_channel:start_link(1, self(), Writer4, <<"user">>, <<"/">>,
-                                    self()),
+    {ok, Ch4} = rabbit_channel:start_link(1, self(), Writer4,
+                                          <<"user">>, <<"/">>, self()),
     ok = rabbit_channel:do(Ch4, #'channel.open'{}),
     MRef4 = erlang:monitor(process, Ch4),
     Writer4 ! sync,
diff --git a/src/rabbit_types.erl b/src/rabbit_types.erl
index 2e492b80..3aaf1917 100644
--- a/src/rabbit_types.erl
+++ b/src/rabbit_types.erl
@@ -39,8 +39,8 @@
               delivery/0, content/0, decoded_content/0, undecoded_content/0,
               unencoded_content/0, encoded_content/0, vhost/0, ctag/0,
               amqp_error/0, r/1, r2/2, r3/3, ssl_socket/0, listener/0,
-              binding/0, amqqueue/0, exchange/0, connection/0, user/0,
-              error/1, ok_or_error/1, ok_or_error2/2, ok/1]).
+              binding/0, amqqueue/0, exchange/0, connection/0, protocol/0,
+              user/0, error/1, ok_or_error/1, ok_or_error2/2, ok/1]).
 
 -type(maybe(T) :: T | 'none').
 -type(vhost() :: binary()).
@@ -133,6 +133,8 @@
 
 -type(connection() :: pid()).
 
+-type(protocol() :: atom()).
+
 -type(user() ::
       #user{username :: rabbit_access_control:username(),
             password :: rabbit_access_control:password()}).
diff --git a/src/rabbit_writer.erl b/src/rabbit_writer.erl
index 80602038..f90ee734 100644
--- a/src/rabbit_writer.erl
+++ b/src/rabbit_writer.erl
@@ -33,14 +33,14 @@
 -include("rabbit.hrl").
 -include("rabbit_framing.hrl").
 
--export([start/3, start_link/3, shutdown/1, mainloop/1]).
+-export([start/4, start_link/4, shutdown/1, mainloop/1]).
 -export([send_command/2, send_command/3, send_command_and_signal_back/3,
          send_command_and_signal_back/4, send_command_and_notify/5]).
--export([internal_send_command/3, internal_send_command/5]).
+-export([internal_send_command/4, internal_send_command/6]).
 
 -import(gen_tcp).
 
--record(wstate, {sock, channel, frame_max}).
+-record(wstate, {sock, channel, frame_max, protocol}).
 
 -define(HIBERNATE_AFTER, 5000).
 
@@ -48,14 +48,14 @@
 
 -ifdef(use_specs).
 
--spec(start/3 ::
+-spec(start/4 ::
         (rabbit_net:socket(), rabbit_channel:channel_number(),
-         non_neg_integer())
-        -> pid()).
--spec(start_link/3 ::
+         non_neg_integer(), rabbit_types:protocol())
+        -> rabbit_types:ok(pid())).
+-spec(start_link/4 ::
         (rabbit_net:socket(), rabbit_channel:channel_number(),
-         non_neg_integer())
-        -> pid()).
+         non_neg_integer(), rabbit_types:protocol())
+        -> rabbit_types:ok(pid())).
 -spec(send_command/2 ::
         (pid(), rabbit_framing:amqp_method_record()) -> 'ok').
 -spec(send_command/3 ::
@@ -70,29 +70,31 @@
         (pid(), pid(), pid(), rabbit_framing:amqp_method_record(),
          rabbit_types:content())
         -> 'ok').
--spec(internal_send_command/3 ::
+-spec(internal_send_command/4 ::
         (rabbit_net:socket(), rabbit_channel:channel_number(),
-         rabbit_framing:amqp_method_record())
+         rabbit_framing:amqp_method_record(), rabbit_types:protocol())
         -> 'ok').
--spec(internal_send_command/5 ::
+-spec(internal_send_command/6 ::
         (rabbit_net:socket(), rabbit_channel:channel_number(),
          rabbit_framing:amqp_method_record(), rabbit_types:content(),
-         non_neg_integer())
+         non_neg_integer(), rabbit_types:protocol())
         -> 'ok').
 
 -endif.
 
 %%----------------------------------------------------------------------------
 
-start(Sock, Channel, FrameMax) ->
-    spawn(?MODULE, mainloop, [#wstate{sock = Sock,
-                                      channel = Channel,
-                                      frame_max = FrameMax}]).
-
-start_link(Sock, Channel, FrameMax) ->
-    spawn_link(?MODULE, mainloop, [#wstate{sock = Sock,
+start(Sock, Channel, FrameMax, Protocol) ->
+    {ok, spawn(?MODULE, mainloop, [#wstate{sock = Sock,
                                            channel = Channel,
-                                           frame_max = FrameMax}]).
+                                           frame_max = FrameMax,
+                                           protocol = Protocol}])}.
+
+start_link(Sock, Channel, FrameMax, Protocol) ->
+    {ok, spawn_link(?MODULE, mainloop, [#wstate{sock = Sock,
+                                                channel = Channel,
+                                                frame_max = FrameMax,
+                                                protocol = Protocol}])}.
 
 mainloop(State) ->
     receive
@@ -102,35 +104,40 @@ mainloop(State) ->
     end.
 
 handle_message({send_command, MethodRecord},
-               State = #wstate{sock = Sock, channel = Channel}) ->
-    ok = internal_send_command_async(Sock, Channel, MethodRecord),
+               State = #wstate{sock = Sock, channel = Channel,
+                               protocol = Protocol}) ->
+    ok = internal_send_command_async(Sock, Channel, MethodRecord, Protocol),
     State;
 handle_message({send_command, MethodRecord, Content},
                State = #wstate{sock = Sock,
                                channel = Channel,
-                               frame_max = FrameMax}) ->
+                               frame_max = FrameMax,
+                               protocol = Protocol}) ->
     ok = internal_send_command_async(Sock, Channel, MethodRecord,
-                                     Content, FrameMax),
+                                     Content, FrameMax, Protocol),
     State;
 handle_message({send_command_and_signal_back, MethodRecord, Parent},
-               State = #wstate{sock = Sock, channel = Channel}) ->
-    ok = internal_send_command_async(Sock, Channel, MethodRecord),
+               State = #wstate{sock = Sock, channel = Channel,
+                               protocol = Protocol}) ->
+    ok = internal_send_command_async(Sock, Channel, MethodRecord, Protocol),
     Parent ! rabbit_writer_send_command_signal,
     State;
 handle_message({send_command_and_signal_back, MethodRecord, Content, Parent},
                State = #wstate{sock = Sock,
                                channel = Channel,
-                               frame_max = FrameMax}) ->
+                               frame_max = FrameMax,
+                               protocol = Protocol}) ->
     ok = internal_send_command_async(Sock, Channel, MethodRecord,
-                                     Content, FrameMax),
+                                     Content, FrameMax, Protocol),
     Parent ! rabbit_writer_send_command_signal,
     State;
 handle_message({send_command_and_notify, QPid, ChPid, MethodRecord, Content},
                State = #wstate{sock = Sock,
                                channel = Channel,
-                               frame_max = FrameMax}) ->
+                               frame_max = FrameMax,
+                               protocol = Protocol}) ->
     ok = internal_send_command_async(Sock, Channel, MethodRecord,
-                                     Content, FrameMax),
+                                     Content, FrameMax, Protocol),
     rabbit_amqqueue:notify_sent(QPid, ChPid),
     State;
 handle_message({inet_reply, _, ok}, State) ->
@@ -171,30 +178,32 @@ shutdown(W) ->
 
 %---------------------------------------------------------------------------
 
-assemble_frames(Channel, MethodRecord) ->
+assemble_frames(Channel, MethodRecord, Protocol) ->
     ?LOGMESSAGE(out, Channel, MethodRecord, none),
-    rabbit_binary_generator:build_simple_method_frame(Channel, MethodRecord).
+    rabbit_binary_generator:build_simple_method_frame(Channel, MethodRecord,
+                                                      Protocol).
 
-assemble_frames(Channel, MethodRecord, Content, FrameMax) ->
+assemble_frames(Channel, MethodRecord, Content, FrameMax, Protocol) ->
     ?LOGMESSAGE(out, Channel, MethodRecord, Content),
     MethodName = rabbit_misc:method_record_type(MethodRecord),
-    true = rabbit_framing:method_has_content(MethodName), % assertion
+    true = Protocol:method_has_content(MethodName), % assertion
     MethodFrame = rabbit_binary_generator:build_simple_method_frame(
-                    Channel, MethodRecord),
+                    Channel, MethodRecord, Protocol),
     ContentFrames = rabbit_binary_generator:build_simple_content_frames(
-                      Channel, Content, FrameMax),
+                      Channel, Content, FrameMax, Protocol),
     [MethodFrame | ContentFrames].
 
 tcp_send(Sock, Data) ->
     rabbit_misc:throw_on_error(inet_error,
                                fun () -> rabbit_net:send(Sock, Data) end).
 
-internal_send_command(Sock, Channel, MethodRecord) ->
-    ok = tcp_send(Sock, assemble_frames(Channel, MethodRecord)).
+internal_send_command(Sock, Channel, MethodRecord, Protocol) ->
+    ok = tcp_send(Sock, assemble_frames(Channel, MethodRecord, Protocol)).
 
-internal_send_command(Sock, Channel, MethodRecord, Content, FrameMax) ->
+internal_send_command(Sock, Channel, MethodRecord, Content, FrameMax,
+                      Protocol) ->
     ok = tcp_send(Sock, assemble_frames(Channel, MethodRecord,
-                                        Content, FrameMax)).
+                                        Content, FrameMax, Protocol)).
 
 %% gen_tcp:send/2 does a selective receive of {inet_reply, Sock,
 %% Status} to obtain the result. That is bad when it is called from
@@ -214,13 +223,14 @@ internal_send_command(Sock, Channel, MethodRecord, Content, FrameMax) ->
 %% Also note that the port has bounded buffers and port_command blocks
 %% when these are full. So the fact that we process the result
 %% asynchronously does not impact flow control.
-internal_send_command_async(Sock, Channel, MethodRecord) ->
-    true = port_cmd(Sock, assemble_frames(Channel, MethodRecord)),
+internal_send_command_async(Sock, Channel, MethodRecord, Protocol) ->
+    true = port_cmd(Sock, assemble_frames(Channel, MethodRecord, Protocol)),
     ok.
 
-internal_send_command_async(Sock, Channel, MethodRecord, Content, FrameMax) ->
+internal_send_command_async(Sock, Channel, MethodRecord, Content, FrameMax,
+                            Protocol) ->
     true = port_cmd(Sock, assemble_frames(Channel, MethodRecord,
-                                              Content, FrameMax)),
+                                          Content, FrameMax, Protocol)),
     ok.
 
 port_cmd(Sock, Data) ->