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    <small><font face="Courier New, Courier, monospace" size="-1"><small><font
            size="-1"><br>
            <font size="-1">the scheme <font size="-1">is</font>    <font
                size="-1">PBX</font></font>---E1--Cisco 2811-----VoIP
            SIP-----<font size="-1">F</font>ree<font size="-1">SWITCH---</font>--</font></small></font></small><small><font
        face="Courier New, Courier, monospace" size="-1"><small><font
            size="-1"><small><font face="Courier New, Courier,
                monospace" size="-1"><small><font size="-1">VoIP SIP</font></small></font></small>---asterisk(1.8.20)</font>---IP
          Phone<br>
          <br>
          <font size="-1"><font size="-1">FreeSWITCH <font size="-1">IP</font>
            </font></font></small></font></small><small><font
        face="Courier New, Courier, monospace" size="-1"><small><font
            size="-1"><font size="-1"><small><font face="Courier New,
                  Courier, monospace" size="-1"><small>is 191.21.19.12</small></font></small></font></font><br>
          <font size="-1">Asterisk IP </font></small></font></small><small><font
        face="Courier New, Courier, monospace" size="-1"><small><font
            size="-1"><small><font face="Courier New, Courier,
                monospace" size="-1"><small>is 162.48.13.26</small></font></small></font><br>
          Call comes to  <font size="-1">F</font>ree<font size="-1">SWITCH</font>
          from a </small></font></small><small><font face="Courier New,
        Courier, monospace" size="-1"><small><small><font face="Courier
              New, Courier, monospace" size="-1"><small><font size="-1">Cisco
                  2811</font></small></font></small>.</small></font></small><small><font
        face="Courier New, Courier, monospace" size="-1"><small><font
            size="-1"><font size="-1"><font size="-1"><small><font
                    face="Courier New, Courier, monospace" size="-1"><small><small><font
                          face="Courier New, Courier, monospace"
                          size="-1"><small><font size="-1"><br>
                            </font></small></font></small></small></font></small></font></font></font><br>
          <font size="-1">SIP session betwee<font size="-1">n  </font></font></small></font></small><small><font
        face="Courier New, Courier, monospace" size="-1"><small><font
            size="-1"><small><font face="Courier New, Courier,
                monospace" size="-1"><small><font size="-1">freeswitch 
                    and </font></small></font></small></font></small></font></small><small><font
        face="Courier New, Courier, monospace" size="-1"><small><font
            size="-1"><small><font face="Courier New, Courier,
                monospace" size="-1"><small><font size="-1"><small><font
                        face="Courier New, Courier, monospace" size="-1"><small><font
                            size="-1">asterisk(1.8.20)</font></small></font></small></font></small></font></small><br>
            <br>
            <br>
          </font>|Time     | 191.21.19.12                          |<br>
          |         |                   | 162.48.13.26     
          |                   <br>
          |21.048754|         INVITE SDP (g711A CN)         |SIP From:
          "91295" &lt;<a class="moz-txt-link-abbreviated" href="mailto:sip:9195@191.21.19.12">sip:9195@191.21.19.12</a> To:&lt;<a class="moz-txt-link-abbreviated" href="mailto:sip:9647@162.48.13.26">sip:9647@162.48.13.26</a><br>
          |         |(5065)   ------------------&gt;  (5060)   |<br>
          |21.048758|         INVITE SDP (g711A CN)         |SIP From:
          "91295" &lt;<a class="moz-txt-link-abbreviated" href="mailto:sip:9195@191.21.19.12">sip:9195@191.21.19.12</a> To:&lt;<a class="moz-txt-link-abbreviated" href="mailto:sip:9647@162.48.13.26">sip:9647@162.48.13.26</a><br>
          |         |(5065)   ------------------&gt;  (5060)   |<br>
          |21.065794|         100 Trying|                   |SIP Status<br>
          |         |(5065)   &lt;------------------  (5060)   |<br>
          |21.122406|         180 Ringing                   |SIP Status<br>
          |         |(5065)   &lt;------------------  (5060)   |<br>
          |21.143580|         RTP (g711A)                   |RTP Num
          packets:50  Duration:0.922s SSRC:0xB5320A6<br>
          |         |(21866)  &lt;------------------  (12772)  |<br>
          |22.282684|         180 Ringing                   |SIP Status<br>
          |         |(5065)   &lt;------------------  (5060)   |<br>
          |22.296762|         181 Call is being forwarded   |SIP Status<br>
          |         |(5065)   &lt;------------------  (5060)   |<br>
          |27.558268|         180 Ringing                   |SIP Status<br>
          |         |(5065)   &lt;------------------  (5060)   |<br>
          |35.039883|         200 OK SDP (g711A)            |SIP Status<br>
          |         |(5065)   &lt;------------------  (5060)   |<br>
          |35.307222|         RTP (g711A)                   |RTP Num
          packets:1490  Duration:29.773s SSRC:0x530CAB37<br>
          |         |(21866)  &lt;------------------  (12772)  |<br>
          |35.476614|         200 OK SDP (g711A)            |SIP Status<br>
          |         |(5065)   &lt;------------------  (5060)   |<br>
          |35.532995|         RTP (g711A)                   |RTP Num
          packets:2966  Duration:29.680s SSRC:0x308FC816<br>
          |         |(21866)  ------------------&gt;  (12772)  |<br>
          |36.436846|         200 OK SDP (g711A)            |SIP Status<br>
          |         |(5065)   &lt;------------------  (5060)   |<br>
          |38.282686|         200 OK SDP (g711A)            |SIP Status<br>
          |         |(5065)   &lt;------------------  (5060)   |<br>
          |42.025399|         200 OK SDP (g711A)            |SIP Status<br>
          |         |(5065)   &lt;------------------  (5060)   |<br>
          |45.637280|         200 OK SDP (g711A)            |SIP Status<br>
          |         |(5065)   &lt;------------------  (5060)   |<br>
          |49.343115|         200 OK SDP (g711A)            |SIP Status<br>
          |         |(5065)   &lt;------------------  (5060)   |<br>
          |53.119940|         200 OK SDP (g711A)            |SIP Status<br>
          |         |(5065)   &lt;------------------  (5060)   |<br>
          |56.907800|         200 OK SDP (g711A)            |SIP Status<br>
          |         |(5065)   &lt;------------------  (5060)   |<br>
          |60.791453|         200 OK SDP (g711A)            |SIP Status<br>
          |         |(5065)   &lt;------------------  (5060)   |<br>
          |64.606730|         200 OK SDP (g711A)            |SIP Status<br>
          |         |(5065)   &lt;------------------  (5060)   |<br>
          |65.219392|         BYE       |                   |SIP Request<br>
          |         |(5065)   &lt;------------------  (5060)   |<br>
          |65.234354|         200 OK    |                   |SIP Status<br>
          |         |(5065)   ------------------&gt;  (5060)   |<br>
          |65.234359|         200 OK    |                   |SIP Status<br>
          |         |(5065)   ------------------&gt;  (5060)   |<br>
        </small></font></small><br>
    <small><font face="Courier New, Courier, monospace" size="-1"><small>It
          is visible that there is no package with ACK confirmation from
          a <font size="-1">Free<font size="-1">SWITCH to Asterisk</font></font>. 
          Asterisk sends several times SIP OK on a <font size="-1">free</font>switch,
          and without having waited confirmations (</small></font></small><small><font
        face="Courier New, Courier, monospace" size="-1"><small><small><font
              face="Courier New, Courier, monospace" size="-1"><small>ACK</small></font></small>)
          after 23 seconds sends SIP BY on a </small></font></small><small><font
        face="Courier New, Courier, monospace" size="-1"><small><small><font
              face="Courier New, Courier, monospace" size="-1"><small><font
                  size="-1">free</font>switch</small></font></small> and
          on IP Phone. <font size="-1">Aft<font size="-1">er that</font></font>
          call stops. Before <font size="-1">disconnection</font>
          subscribers hear each other of <font size="-1">29</font> (+-)
          seconds<br>
          <br>
          <font size="-1"><font size="-1">In <font size="-1">tcpdump</font>
              between Cisco and Free<font size="-1">SWITCH</font> it is
              visible that the SIP ACK <font size="-1">packet from
                Cisco arrives on a </font></font></font></small></font></small><small><font
        face="Courier New, Courier, monospace" size="-1"><small><font
            size="-1"><font size="-1"><font size="-1"><small><font
                    face="Courier New, Courier, monospace" size="-1"><small><small><font
                          face="Courier New, Courier, monospace"
                          size="-1"><small><font size="-1">free</font>switch<font
                              size="-1">.</font></small></font></small></small></font></small></font></font></font></small></font></small><br>
    <br>
    <small><font face="Courier New, Courier, monospace">In what place
        the SIP ACK in a FreeSWITCH disappeared?<br>
        What to me to analyse in SIP session?<br>
        Maybe someone solved a similar problem?</font></small><br>
    <small><font face="Courier New, Courier, monospace">please, Help!</font></small><br>
    <br>
    <font face="Courier New" size="2" color="black"><span
        style="font-size:10.0pt; font-family:&quot;Courier
        New&quot;;color:black" lang="EN-US">Vladislav Grishin</span></font><br>
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