anchor.diff:  	    #local_ipv4_address{ip_address = <<127,0,0,1>>},
   	    #result_code{result_code = 0}],
       Header = #capwap_header{radio_id = RadioId, wb_id = WBID, flags = Flags},
  -    State = send_response(Header, join_response, Seq, RespElements, State1),
  +    Data = send_response(Header, join_response, Seq, RespElements, Data1),
       SessionOpts = wtp_accounting_infos(Elements, [{'CAPWAP-Radio-Id', RadioId}]),
       lager:info("WTP Session Start Opts: ~p", [SessionOpts]),
   
  
positive.code: 	    NotifyFun = start_gtk_rekey_result(WlanIdent, Stations, _, _, _)
      end,
  
      State1 = update_wlan_state(WlanIdent, fun(_W) -> Wlan end, State0),
      send_request(Header, ieee_802_11_wlan_configuration_request, ReqElements, NotifyFun, State1);
  
  start_gtk_rekey({RadioId, WlanId}, Wlan, State) ->
      lager:warning("failed to start GTK rekey for ~w:~w (~p)", [RadioId, WlanId, lager:pr(Wlan, ?MODULE)]),
      State.
  
  %% Note: failures will be handled the FSM event function
  start_gtk_rekey_result(WlanIdent, Stations, Code, _Arg, State)
    when Code == 0 ->
      update_wlan_state(WlanIdent,
  		      fun(W = #wlan{gtk = GTK, igtk = IGTK}) ->
  			      {ok, _Pid} = capwap_ac_gtk_rekey:start_link({self(), WlanIdent},
  									  GTK, IGTK, Stations),
  			      W#wlan{group_rekey_state = running}
  		      end, State);
  
  start_gtk_rekey_result(WlanIdent, _Stations, _Code, _Arg, State) ->
      update_wlan_state(WlanIdent, fun(W) -> W#wlan{group_rekey_state = failed} end, State).
  
  
  
  
  finish_gtk_rekey(WlanIdent = {RadioId, WlanId},
  		 Wlan0 = #wlan{group_rekey_state = running},
  		 State0) ->
      WBID = ?CAPWAP_BINDING_802_11,
      Flags = [{frame,'802.3'}],
      Header = #capwap_header{radio_id = RadioId, wb_id = WBID, flags = Flags},
  
negative.code:     StartTime = erlang:system_time(milli_seconds),
      MacTypes = ie(wtp_mac_type, Elements),
      TunnelModes = ie(wtp_frame_tunnel_mode, Elements),
      Data1 = Data0#data{config = Config,
  			  session_id = SessionId, mac_types = MacTypes,
  			  tunnel_modes = TunnelModes, version = Version,
  			  location = ie(location_data, Elements),
  