|Time     | sip provider                          | IP (2) proxy      |                   |
|         |                   | IP (1) proxy      |                   | Customer IPBX     |                   
|0,000    |         INVITE SDP ype-101 )          |                   |                   |
|         |(5060)   ------------------>  (5060)   |                   |                   |
|0,000    |         100 Trying|                   |                   |                   |SIP Status
|         |(5060)   <------------------  (5060)   |                   |                   |
|0,000    |         100 Giving a try              |                   |                   |SIP Status
|         |(5060)   <------------------  (5060)   |                   |                   |
|0,000    |         180 Ringing                   |                   |                   |SIP Status
|         |(5060)   <------------------  (5060)   |                   |                   |
|0,000    |                   |                   |         INVITE SDP                    |SIP Request
|         |                   |                   |(5060)   ------------------>  (5060)   |
|0,190    |                   |                   |         100 Trying|                   |SIP Status
|         |                   |                   |(5060)   <------------------  (5060)   |
|0,285    |                   |                   |         183 Session Progress          |SIP Status
|         |                   |                   |(5060)   <------------------  (5060)   |
|0,285    |                   |                   |         180 Ringing                   |SIP Status
|         |                   |                   |(5060)   <------------------  (5060)   |
|0,285    |         180 Ringing                   |                   |                   |SIP Status
|         |(5060)   <------------------  (5060)   |                   |                   |
|1,818    |                   |                   |         200 OK SDP (g711A)            |SIP Status
|         |                   |                   |(5060)   <------------------  (5060)   |
|1,818    |         200 OK SDP (g711A)            |                   |                   |SIP Status
|         |(5060)   <------------------  (5060)   |                   |                   |
|1,818    |         ACK       |                   |                   |                   |SIP Request
|         |(5060)   ------------------>  (5060)   |                   |                   |
|2,289    |         200 OK SDP (g711A)            |                   |                   |SIP Status
|         |(5060)   <------------------  (5060)   |                   |                   |
|2,289    |                   |                   |         200 OK SDP (g711A)            |SIP Status
|         |                   |                   |(5060)   <------------------  (5060)   |
|2,289    |         ACK       |                   |                   |                   |SIP Request
|         |(5060)   ------------------>  (5060)   |                   |                   |
|3,242    |                   |                   |         200 OK SDP (g711A)            |SIP Status
|         |                   |                   |(5060)   <------------------  (5060)   |
|3,338    |         ACK       |                   |                   |                   |SIP Request
|         |(5060)   ------------------>  (5060)   |                   |                   |
|3,338    |         200 OK SDP (g711A)            |                   |                   |SIP Status
|         |(5060)   <------------------  (5060)   |                   |                   |
|5,277    |         200 OK SDP (g711A)            |                   |                   |SIP Status
|         |(5060)   <------------------  (5060)   |                   |                   |
|5,277    |                   |                   |         200 OK SDP (g711A)            |SIP Status
|         |                   |                   |(5060)   <------------------  (5060)   |
|5,278    |         ACK       |                   |                   |                   |SIP Request
|         |(5060)   ------------------>  (5060)   |                   |                   |
|9,245    |                   |                   |         200 OK SDP (g711A)            |SIP Status
|         |                   |                   |(5060)   <------------------  (5060)   |
|13,259   |                   |                   |         200 OK SDP (g711A)            |SIP Status
|         |                   |                   |(5060)   <------------------  (5060)   |
|17,336   |                   |                   |         200 OK SDP (g711A)            |SIP Status
|         |                   |                   |(5060)   <------------------  (5060)   |
|21,304   |                   |                   |         200 OK SDP (g711A)            |SIP Status
|         |                   |                   |(5060)   <------------------  (5060)   |
|25,243   |                   |                   |         200 OK SDP (g711A)            |SIP Status
|         |                   |                   |(5060)   <------------------  (5060)   |
|29,291   |                   |                   |         200 OK SDP (g711A)            |SIP Status
|         |                   |                   |(5060)   <------------------  (5060)   |
|33,328   |                   |                   |         200 OK SDP (g711A)            |SIP Status
|         |                   |                   |(5060)   <------------------  (5060)   |
|60,716   |         BYE       |                   |                   |                   |SIP Request
|         |(5060)   ------------------>  (5060)   |                   |                   |
|60,716   |         404 Not here                  |                   |                   |SIP Status
|         |(5060)   <------------------  (5060)   |                   |                   |
|239,836  |         BYE       |                   |                   |                   |SIP Request
|         |(5060)   <------------------  (5060)   |                   |                   |
|239,836  |                   |                   |         BYE       |                   |SIP Request
|         |                   |                   |(5060)   ------------------>  (5060)   |
|239,837  |         481 Call Leg/Transaction Does Not Exist          |                   |                   |SIP Status
|         |(5060)   ------------------>  (5060)   |                   |                   |
|239,931  |                   |                   |         481 Call/Transaction Does Not Exist          |SIP Status
|         |                   |                   |(5060)   <------------------  (5060)   |