diff --git a/src/xua_asp_fsm.erl b/src/xua_asp_fsm.erl
new file mode 100644
index 0000000..a02f70c
--- /dev/null
+++ b/src/xua_asp_fsm.erl
@@ -0,0 +1,227 @@
+% SCCP M3UA / SUA ASP gsn_fsm according to RFC3868 4.3.1
+
+% (C) 2011-2012 by Harald Welte <laforge@gnumonks.org>
+%
+% All Rights Reserved
+%
+% This program is free software; you can redistribute it and/or modify
+% it under the terms of the GNU Affero General Public License as
+% published by the Free Software Foundation; either version 3 of the
+% License, or (at your option) any later version.
+%
+% This program is distributed in the hope that it will be useful,
+% but WITHOUT ANY WARRANTY; without even the implied warranty of
+% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+% GNU General Public License for more details.
+%
+% You should have received a copy of the GNU Affero General Public License
+% along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+-module(xua_asp_fsm).
+-author('Harald Welte <laforge@gnumonks.org>').
+-behaviour(gen_fsm).
+
+-include("osmo_util.hrl").
+-include("m3ua.hrl").
+
+% gen_fsm exports
+-export([init/1, terminate/3, code_change/4, handle_event/3, handle_info/3]).
+
+% states in this FSM
+-export([asp_down/2, asp_inactive/2, asp_active/2]).
+
+% helper functions exporte to callback modules
+-export([send_sctp_to_peer/2, send_prim_to_user/2]).
+
+-export([behaviour_info/1]).
+
+behaviour_info(callbacks) ->
+	[{gen_xua_msg, 3}, {asp_down, 3}, {asp_inactive, 3}, {asp_active, 3}].
+
+% Timeouts in milliseconds
+-define(T_ACK_TIMEOUT, 2*60*100).
+
+-record(asp_state, {
+		module,
+		role,
+		t_ack,
+		ext_state,
+		user_fun,
+		user_args,
+		sctp_pid
+	}).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% gen_fsm callbacks
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+init([Module, ModuleArgs, UserFun, UserArgs, SctpPid]) ->
+	{ok, ExtState} = Module:init(ModuleArgs),
+	AspState = #asp_state{module = Module,
+			      user_fun = UserFun,
+			      user_args = UserArgs,
+			      ext_state = ExtState,
+			      sctp_pid = SctpPid,
+			      role = asp},
+	{ok, asp_down, AspState}.
+
+terminate(Reason, State, _LoopDat) ->
+	io:format("Terminating ~p in State ~p (Reason: ~p)~n",
+		  [?MODULE, State, Reason]),
+	ok.
+
+code_change(_OldVsn, StateName, LoopDat, _Extra) ->
+	{ok, StateName, LoopDat}.
+
+handle_event(Event, State, LoopDat) ->
+	io:format("Unknown Event ~p in state ~p~n", [Event, State]),
+	{next_state, State, LoopDat}.
+
+
+handle_info(Info, State, LoopDat) ->
+	io:format("Unknown Info ~p in state ~p~n", [Info, State]),
+	{next_state, State, LoopDat}.
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% STATE "asp_down"
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+asp_down(#primitive{subsystem = 'M', gen_name = 'ASP_UP',
+		    spec_name = request, parameters = _Params}, LoopDat) ->
+	% M-ASP_UP.req from user, generate message and send to remote peer
+	send_msg_start_tack(LoopDat, asp_down, ?M3UA_MSGC_ASPSM, ?M3UA_MSGT_ASPSM_ASPUP, []);
+asp_down({timer_expired, t_ack, {?M3UA_MSGC_ASPSM, ?M3UA_MSGT_ASPSM_ASPUP, Params}}, LoopDat) ->
+	send_msg_start_tack(LoopDat, asp_down, ?M3UA_MSGC_ASPSM, ?M3UA_MSGT_ASPSM_ASPUP, Params);
+
+asp_down({xua_msg, ?M3UA_MSGC_ASPSM, ?M3UA_MSGT_ASPSM_ASPUP_ACK}, LoopDat) ->
+	timer:cancel(LoopDat#asp_state.t_ack),
+	% transition into ASP_INACTIVE
+	send_prim_to_user(LoopDat, osmo_util:make_prim('M','ASP_UP',confirm)),
+	{next_state, asp_inactive, LoopDat};
+
+asp_down(WhateverElse, LoopDat = #asp_state{module = Module, ext_state = ExtState}) ->
+	Module:asp_down(WhateverElse, ExtState, LoopDat).
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% STATE "asp_inactive"
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+asp_inactive(#primitive{subsystem = 'M', gen_name = 'ASP_ACTIVE',
+			spec_name = request, parameters = Params}, LoopDat) ->
+	% M-ASP_ACTIVE.req from user, generate message and send to remote peer
+	send_msg_start_tack(LoopDat, asp_inactive, ?M3UA_MSGC_ASPTM, ?M3UA_MSGT_ASPTM_ASPAC,
+			   Params);
+
+asp_inactive({timer_expired, t_ack, {?M3UA_MSGC_ASPTM, ?M3UA_MSGT_ASPTM_ASPAC, Params}}, LoopDat) ->
+	send_msg_start_tack(LoopDat, asp_inactive, ?M3UA_MSGC_ASPTM, ?M3UA_MSGT_ASPTM_ASPAC, Params);
+
+asp_inactive(#primitive{subsystem = 'M', gen_name = 'ASP_DOWN',
+		      spec_name = request, parameters = _Params}, LoopDat) ->
+	% M-ASP_DOWN.req from user, generate message and send to remote peer
+	send_msg_start_tack(LoopDat, asp_inactive, ?M3UA_MSGC_ASPSM, ?M3UA_MSGT_ASPSM_ASPDN, []);
+
+asp_inactive({timer_expired, t_ack, {?M3UA_MSGC_ASPSM, ?M3UA_MSGT_ASPSM_ASPDN, Params}}, LoopDat) ->
+	send_msg_start_tack(LoopDat, asp_inactive, ?M3UA_MSGC_ASPSM, ?M3UA_MSGT_ASPSM_ASPDN, Params);
+
+asp_inactive({xua_msg,?M3UA_MSGC_ASPTM, ?M3UA_MSGT_ASPTM_ASPAC_ACK}, LoopDat) ->
+	timer:cancel(LoopDat#asp_state.t_ack),
+	% transition into ASP_ACTIVE
+	% signal this to the user
+	send_prim_to_user(LoopDat, osmo_util:make_prim('M','ASP_ACTIVE',confirm)),
+	{next_state, asp_active, LoopDat};
+
+asp_inactive({xua_msg, ?M3UA_MSGC_ASPSM, ?M3UA_MSGT_ASPSM_ASPDN_ACK}, LoopDat) ->
+	timer:cancel(LoopDat#asp_state.t_ack),
+	% transition into ASP_DOWN
+	% signal this to the user
+	send_prim_to_user(LoopDat, osmo_util:make_prim('M','ASP_DOWN',confirm)),
+	{next_state, asp_down, LoopDat};
+
+asp_inactive(WhateverElse, LoopDat = #asp_state{module = Module, ext_state = ExtState}) ->
+	Module:asp_inactive(WhateverElse, ExtState, LoopDat).
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% STATE "asp_active"
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+asp_active({xua_msg, ?M3UA_MSGC_ASPSM, ?M3UA_MSGT_ASPSM_ASPDN_ACK}, LoopDat) ->
+	timer:cancel(LoopDat#asp_state.t_ack),
+	% transition into ASP_DOWN
+	% signal this to the user
+	send_prim_to_user(LoopDat, osmo_util:make_prim('M','ASP_DOWN',confirm)),
+	{next_state, asp_down, LoopDat};
+
+asp_active({xua_msg, ?M3UA_MSGC_ASPTM, ?M3UA_MSGT_ASPTM_ASPIA_ACK}, LoopDat) ->
+	timer:cancel(LoopDat#asp_state.t_ack),
+	% transition into ASP_INACTIVE
+	% signal this to the user
+	send_prim_to_user(LoopDat, osmo_util:make_prim('M','ASP_INACTIVE',confirm)),
+	{next_state, asp_inactive, LoopDat};
+
+asp_active(#primitive{subsystem = 'M', gen_name = 'ASP_DOWN',
+		      spec_name = request, parameters = _Params}, LoopDat) ->
+	% M-ASP_DOWN.req from user, generate message and send to remote peer
+	send_msg_start_tack(LoopDat, asp_active, ?M3UA_MSGC_ASPSM, ?M3UA_MSGT_ASPSM_ASPDN, []);
+
+asp_active({timer_expired, t_ack, {?M3UA_MSGC_ASPSM, ?M3UA_MSGT_ASPSM_ASPDN, Params}}, LoopDat) ->
+	send_msg_start_tack(LoopDat, asp_active, ?M3UA_MSGC_ASPSM, ?M3UA_MSGT_ASPSM_ASPDN, Params);
+
+asp_active(#primitive{subsystem = 'M', gen_name = 'ASP_INACTIVE',
+		      spec_name = request, parameters = _Params}, LoopDat) ->
+	% M-ASP_INACTIVE.req from user, generate message and send to remote peer
+	send_msg_start_tack(LoopDat, asp_active, ?M3UA_MSGC_ASPTM, ?M3UA_MSGT_ASPTM_ASPIA, []);
+
+asp_active({timer_expired, t_ack, {?M3UA_MSGC_ASPTM, ?M3UA_MSGT_ASPTM_ASPIA, Params}}, LoopDat) ->
+	send_msg_start_tack(LoopDat, asp_active, ?M3UA_MSGC_ASPTM, ?M3UA_MSGT_ASPTM_ASPIA, Params);
+
+asp_active(#primitive{subsystem = 'MTP', gen_name = 'TRANSFER',
+		      spec_name = request, parameters = Params}, LoopDat) ->
+	% MTP-TRANSFER.req from user app: Send message to remote peer
+	OptList = [{?M3UA_IEI_PROTOCOL_DATA, Params}],
+	Msg = #m3ua_msg{version = 1, msg_class = ?M3UA_MSGC_TRANSFER,
+			msg_type = ?M3UA_MSGT_XFR_DATA,
+			payload = OptList},
+	send_sctp_to_peer(LoopDat, Msg),
+	{next_state, asp_active, LoopDat};
+asp_active(#m3ua_msg{version = 1, msg_class = ?M3UA_MSGC_TRANSFER,
+		     msg_type = ?M3UA_MSGT_XFR_DATA, payload = Params}, LoopDat) ->
+	% Data transfer from remote entity: Send MTP-TRANSFER.ind primitive to the user
+	Mtp3 = proplists:get_value(?M3UA_IEI_PROTOCOL_DATA, Params),
+	send_prim_to_user(LoopDat, osmo_util:make_prim('MTP','TRANSFER',indication,Mtp3)),
+	{next_state, asp_active, LoopDat};
+
+asp_active(WhateverElse, LoopDat = #asp_state{module = Module, ext_state = ExtState}) ->
+	Module:asp_active(WhateverElse, ExtState, LoopDat).
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% helper functions
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+% helper to send one of the up/down/act/inact management messages + start timer
+send_msg_start_tack(LoopDat, State, MsgClass, MsgType, Params) ->
+	Module = LoopDat#asp_state.module,
+	% generate and send the respective message
+	%Msg = #m3ua_msg{version = 1, msg_class = MsgClass, msg_type = MsgType, payload = Params},
+	Msg = Module:gen_xua_msg(MsgClass, MsgType, Params),
+	send_sctp_to_peer(LoopDat, Msg),
+	% start T(ack) timer and wait for ASP_UP_ACK
+	timer:cancel(LoopDat#asp_state.t_ack),
+	{ok, Tack} = timer:apply_after(?T_ACK_TIMEOUT, gen_fsm, send_event,
+				 [self(), {timer_expired, t_ack, {MsgClass, MsgType, Params}}]),
+	{next_state, State, LoopDat#asp_state{t_ack = Tack}}.
+
+
+send_prim_to_user(LoopDat, Prim) when is_record(LoopDat, asp_state),
+				      is_record(Prim, primitive) ->
+	#asp_state{user_fun = Fun, user_args = Args} = LoopDat,
+	Fun(Prim, Args).
+
+
+% Helper function to send data to the SCTP peer
+send_sctp_to_peer(LoopDat, Msg) ->
+	Prim = osmo_util:make_prim('MTP','TRANSFER',request, Msg),
+	gen_fsm:send_event(LoopDat#asp_state.sctp_pid, Prim).