<div dir="ltr">Hello all;<br>I need some Clarification about timestamp header in RFC 3261; i need to use it to estimate the RTT value;<br>how it is work in this scenario?:<br><br>           Invite                                                     <br>

  UA --------------------&gt;   Proxy1<br>   |                                |          Invite<br>   |                                | ------------------------------<div dir="ltr">---------&gt;Proxy2<br>   |                 100 trying |                                             |<br>

   |   &lt;---------------------------|                                             |          invite<br>   |                                |                                             |<br>   |                                |                                             | ---------------------------------------&gt;UA2<br>

   |                                | &lt;-------100 trying-------------------  |                                            |<br>   |                                |                                             | &lt;--------180 Ringing--------------  | <br>

   |                                | &lt;---------------180 Ringing-------   |                                            | <br>   |                                |                                             |                                            |<br>

   |&lt;---180 Ringing----------|                                             |                                            |<br><br><br>UA
send invite to proxy1 with timestamp=10 ; then the Proxy1 send the
invite message to proxy2 and reply with provisional response (100
trying) and with timestamp=10 0.5; <br>
<br>When UA receive 100trying; UA will adapt its retransmition timer T1 to the calculated value from timestamp; <br>then UA adapt T2 Timer value; is This true?<br><br>Here Can Proxy1 send invite message with timestamp header?;<br>

 for example timestamp=8 and when proxy2 recive invite request, it send it to UA and he send 100 trying to proxy1 with<br> timestamp=8  0.4;<br> <br>Please Help me;<br>Thanks;<br>Mustafa AL Rifaee<br></div></div>