When originating a call the respective call channel's call state is set to RINGING right after progress 100 is received. 

Here's the captured flow:

|Time     | <src ip>                              |
|         |                   | <dst ip>          |                   
|2.848    |         INVITE SDP (g711A g711U GSM telephone-eventRTP...e-101 CN)          |SIP From: "" <sip:endpoint removed To:<sip:endpoint removed
|         |(5080)   ------------------>  (5060)   |
|2.848    |         407 Proxy Authentication Required          |SIP Status
|         |(5080)   <------------------  (5060)   |
|2.849    |         ACK       |                   |SIP Request
|         |(5080)   ------------------>  (5060)   |
|2.849    |         INVITE SDP (g711A g711U GSM telephone-eventRTP...e-101 CN)          |SIP From: "" <sip:endpoint removed To:<sip:endpoint removed
|         |(5080)   ------------------>  (5060)   |
|2.850    |         100 Trying|                   |SIP Status
|         |(5080)   <------------------  (5060)   |
|13.444   |         180 Ringing                   |SIP Status
|         |(5080)   <------------------  (5060)   |
|13.445   |         183 Session Progress SDP (g711A g711U GSM tele...ne-eventRTPType-101)          |SIP Status
|         |(5080)   <------------------  (5060)   |
|13.445   |         RTP (g711A)                   |RTP Num packets:230  Duration:4.574s SSRC:0x1E777E26
|         |(26056)  <------------------  (19312)  |
|13.601   |         RTP (g711A)                   |RTP Num packets:220  Duration:4.419s SSRC:0xA530C519
|         |(26056)  ------------------>  (19312)  |

After the 100 Trying is received the switch executes switch_channel_perform_set_running_state (switch_channel.c) and the channel call state is set to RINGING and ESL event CHANNEL_CALLSTATE:RINGING is generated.

I would expect the channel call state to be set to RINGING only after 180 Ringing is received from the far endpoint.

Could anybody give me a hint what could be wrong or what steps to take to figure out? I am already out of ideas.

Thanks!
Hynek