[Freeswitch-users] Hangup cause when destination is busy

[mbo]

Hi,

I’m originating a call from FREESWITCH1 to FREESWITCH2, which bridges the call via a gateway to a carrier. 

FREESWITCH1 -> FREESWITCH2 -> CARRIER 

Freeswitch2 only executes a simple dialplan like: 

<extension name="bt">
  <condition field="destination_number" expression="^(\\+\d{5,20})$">
    <action application="bridge" data="sofia/gateway/bt/${destination_number}"/>
  </condition>
</extension>    


When the destination is BUSY, I can see in the logs 

...
[NOTICE] switch_core_state_machine.c:313 sofia/internal/XXXXXXXXXX has executed the last dialplan instruction, hanging up.
[NOTICE] switch_core_state_machine.c:315 Hangup sofia/internal/XXXXXXXXXX [CS_EXECUTE] [NORMAL_CLEARING]
…

FREESWITCH2 hangs up with cause NORMAL_CLEARING after the bridge, and then sends 

...

 SIP/2.0 486 Busy Here
   Via: SIP/2.0/UDP 192.168.154.100:5080;rport=5080;branch=z9hG4bK18gUcH38BXQ8H
   Max-Forwards: 65
   From: „XXXXXXXXXXXXX>;tag=S4SS3j0HyUv2Q
   To: <XXXXXXXXXXXXX>;tag=B7XU8ZtQUDvrF
   Call-ID: b61b6f21-b9ab-1232-5abc-00163e6b3124
   CSeq: 65177338 INVITE
   User-Agent: FreeSWITCH-mod_sofia/1.4.6+git~20140603T193516Z~9479729340~64bit
   Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, INFO, UPDATE, REGISTER, REFER, NOTIFY, PUBLISH, SUBSCRIBE
   Supported: timer, path, replaces
   Allow-Events: talk, hold, conference, presence, as-feature-event, dialog, line-seize, call-info, sla, include-session-description, presence.winfo, message-summary, refer
   Reason: Q.850;cause=16;text="NORMAL_CLEARING"
   Content-Length: 0
   X-FS-Display-Name: Outbound Call
   X-FS-Display-Number: XXXXXXXXXXXX
   Remote-Party-ID: "Outbound Call“ <XXXXXXXXXXXX>;party=calling;privacy=off;screen=no
…

to FREESWITCH1. In the CDR on FREESWITCH1, the hangup cause for the call is NORMAL_CLEARING and not USER_BUSY.
Does this really works as designed or shouldn’t it hangup with hangup cause „USER_BUSY" and then set "Reason: Q.850;cause=17;text=„USER_BUSY“" in the SIP/2.0 486 Busy Here message, which is sent to FREESWITCH1?