diff --git a/apps/of_switch/src/ofs_userspace_port.erl b/apps/of_switch/src/ofs_userspace_port.erl
index 78c6565..f5d9e43 100644
--- a/apps/of_switch/src/ofs_userspace_port.erl
+++ b/apps/of_switch/src/ofs_userspace_port.erl
@@ -58,7 +58,7 @@
                 rate_bps :: integer(),
                 throttling_ets :: ets:tid()}).
 
--define(DEFAULT_QUEUE, 0).
+-define(DEFAULT_QUEUE, default).
 
 %%%-----------------------------------------------------------------------------
 %%% API functions
@@ -207,14 +207,20 @@ remove(PortNo) ->
                              {ok, #state{}, timeout()} |
                              ignore |
                              {stop, Reason :: term()}.
-init(Args) ->
+init({OfsPortNo, ConfigOpts}) ->
     process_flag(trap_exit, true),
     %% epcap crashes if this dir does not exist.
     filelib:ensure_dir(filename:join([code:priv_dir(epcap), "tmp", "ensure"])),
-    {interface, Interface} = lists:keyfind(interface, 1, Args),
-    {ofs_port_no, OfsPortNo} = lists:keyfind(ofs_port_no, 1, Args),
-    {queues, Queues} = lists:keyfind(queues, 1, Args),
-    {rate, RateDesc} = lists:keyfind(rate, 1, Args),
+
+    {ok, BackendOpts} = application:get_env(of_switch, backends),
+    {userspace, UserspaceOpts} = lists:keyfind(userspace, 1, BackendOpts),
+    {ports, UserspacePorts} = lists:keyfind(ports, 1, UserspaceOpts),
+    {OfsPortNo, PortOpts} = lists:keyfind(OfsPortNo, 1, UserspacePorts),
+
+    {interface, Interface} = lists:keyfind(interface, 1, PortOpts),
+    {rate, RateDesc} = lists:keyfind(rate, 1, ConfigOpts),
+    {queues, Queues} = lists:keyfind(queues, 1, ConfigOpts),
+
     Rate = rate_desc_to_bps(RateDesc),
     State = case re:run(Interface, "^tap.*$", [{capture, none}]) of
                 %% When switch connects to a tap interface, erlang receives file
@@ -229,7 +235,7 @@ init(Args) ->
                                 %% programatically as they can't be created in
                                 %% persistent mode before node startup.
                                 {unix, darwin} ->
-                                    {ip, IP} = lists:keyfind(ip, 1, Args),
+                                    {ip, IP} = lists:keyfind(ip, 1, PortOpts),
                                     ok = tuncer:up(Ref, IP);
                                 %% We assume that under linux TAP interfaces are
                                 %% already set up in persistent state and
@@ -289,6 +295,10 @@ init(Args) ->
                                  ofs_port_no = OfsPortNo,
                                  rate_bps = Rate,
                                  throttling_ets = ThrottlingEts},
+
+            %% Add default queue with no min or max rate
+            do_attach_queue(State1, default, []),
+
             State2 = lists:foldl(fun({QueueId, QueueOpts}, StateAcc) ->
                                      do_attach_queue(StateAcc,
                                                      QueueId,
@@ -475,18 +485,16 @@ unit_to_bps(gbps) -> 1000 * 1000 * 1000;
 unit_to_bps(gibps) -> 1024 * 1024 * 1024.
 
 get_min_rate_bps(QueueProps, PortRateBps) ->
-    case lists:keyfind(ofp_queue_prop_min_rate, 1, QueueProps) of
-        #ofp_queue_prop_min_rate{rate = Rate} when Rate =< 1000 ->
+    case lists:keyfind(min_rate, 1, QueueProps) of
+        {min_rate, Rate} when Rate =< 1000 ->
             Rate * PortRateBps div 1000;
-        #ofp_queue_prop_min_rate{} ->
-            no_qos;
         false ->
-            0
+            no_qos
     end.
 
 get_max_rate_bps(QueueProps, PortRateBps) ->
-    case lists:keyfind(ofp_queue_prop_max_rate, 1, QueueProps) of
-        #ofp_queue_prop_max_rate{rate = Rate} when Rate =< 1000 ->
+    case lists:keyfind(max_rate, 1, QueueProps) of
+        {max_rate, Rate} when Rate =< 1000 ->
             Rate * PortRateBps div 1000;
         _ ->
             no_max_rate
diff --git a/rel/files/sys.config b/rel/files/sys.config
index ea58efe..356acd2 100644
--- a/rel/files/sys.config
+++ b/rel/files/sys.config
@@ -4,33 +4,44 @@
    {controllers,
     [
      %% If you want to connect to the controller,
-     %% specify its hostname and port as in following example:
+     %% specify its hostname and port as in the following example:
      %% {"localhost", 6633}
     ]},
    {ports,
     [
-     %% Configure ports available to switch according to your
-     %% system setup.
-     %% * Under Linux all TAP interfaces must be set up beforehand as
-     %%   persistent.
-     %% * Under MacOSX TAP interfaces are created during node startup.
-     %% * Each port must have at least one queue defined.
-     %% * queues tuple has list of queue tuples with format {queue_id, []
-     %% * spec for port entry:
-     %%   list({ofs_port_no, integer()}
-     %%        | {interface, string()}
-     %%        | {queues, [{integer(), [of_protocol:ofp_queue_property()]}]},
-     %%        | {rate, {integer(), bps|kbps|kibps|mbps|mibps|gbps|gibps}}).
+     %% Configure port features. This part of the configuration will be handled
+     %% by the OF-Config protocol in future releases of LINC.
+     %% * Spec for port entry:
+     %% [{integer(),
+     %%   [{rate, {integer(), bps|kbps|kibps|mbps|mibps|gbps|gibps}} |
+     %%    {queues, [{integer(), [{min_rate, integer()} |
+     %%                           {max_rate, integer()}]}]}]]
      %% * Sample port entries:
-     %%   [{ofs_port_no, 1},
-     %%    {interface, "eth0"},
-     %%    {queues, [{1, [{ofp_queue_prop_min_rate, 20},
-     %%                   {ofp_queue_prop_max_rate, 80}]}]},
-     %%    {rate, {200, kibps}}],
-     %%   [{ofs_port_no, 2},
-     %%    {interface, "tap0"},
-     %%    {queues, [{1, [{ofp_queue_prop_max_rate, 90}]}]},
-     %%    {rate, {100, kibps}}]
+     %% {1, [
+     %%      {rate, {200, kibps}},
+     %%      {queues, [{1, [{min_rate, 20},
+     %%                     {max_rate, 80}]}]}
+     %%     ]},
+     %% {2, [
+     %%      {rate, {100, kibps}},
+     %%      {queues, [{1, [{max_rate, 90}]}]}
+     %%     ]}
+    ]},
+   {backends,
+    [
+     {userspace, [
+                  %% Configure ports available to the switch when using the
+                  %% userspace backend according to your system setup.
+                  %% * Under Linux all TAP interfaces must be set up beforehand
+                  %%   as persistent.
+                  %% * Under MacOSX TAP interfaces are created during node
+                  %%   startup.
+                  {ports,
+                   [
+                    %% {1, [{interface, "eth0"}]},
+                    %% {2, [{interface, "tap0"}]}
+                   ]}
+                 ]}
     ]}
   ]},
  {lager,