anchor.diff:  	{ok, Prim, LoopDat}.
   
   
  -% sctp_core indicates that ew have received some data...
  +% sctp_core indicates that we have received some data...
   rx_sctp(#sctp_sndrcvinfo{ppid = ?M2PA_PPID}, Data, State, LoopDat) ->
   	{ok, M2pa} = m2pa_codec:parse_msg(Data),
   	FsnRecv = M2pa#m2pa_msg.fwd_seq_nr,
  
positive.code: 		#m2pa_msg{msg_class = ?M2PA_CLASS_M2PA,
  			  msg_type = ?M2PA_TYPE_USER} ->
  			Mtp3 = M2pa#m2pa_msg.mtp3,
  			Prim = osmo_util:make_prim('MTP','TRANSFER',indication, Mtp3),
  			{ok, Prim, LoopDat#m2pa_state{last_bsn_received = FsnRecv}};
  		#m2pa_msg{msg_type = ?M2PA_TYPE_LINK} ->
  			handle_linkstate(M2pa, LoopDat),
  			{ignore, LoopDat};
  
negative.code: 	tx_sctp(Stream, M2paBin),
  	LoopDat.
  
  send_userdata_ack(LoopDat) ->
  	M2pa = #m2pa_msg{msg_class = ?M2PA_CLASS_M2PA,
  			 msg_type = ?M2PA_TYPE_USER,
  			 fwd_seq_nr = LoopDat#m2pa_state.last_fsn_sent,
  			 back_seq_nr = LoopDat#m2pa_state.last_bsn_received},
  	M2paBin = m2pa_codec:encode_msg(M2pa),
  	tx_sctp(0, M2paBin).
  
  tx_sctp(Stream, Payload) when is_integer(Stream), is_binary(Payload) ->
  	Param = {Stream, ?M2PA_PPID, Payload},
  	% sent to 'ourselves' (behaviour master module)
  