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<font face="Arial" size="2"><span class="656214310-24052006"></span></font>
<blockquote
cite="midA0E9DBAAF59F2C49AB566EC7B3907872136A69@EXCH1.superinternet.net.sg"
type="cite">
<div><font face="Arial" size="2"><span class="656214310-24052006">I
notice during the NGREP session , there is this field called Call-ID .
It is something like this format :-</span></font></div>
<div><font face="Arial" size="2"><a
href="mailto:9ce97fd3-1a800040@172.16.1.123">9ce97fd3-1a800040@172.16.1.1<span
class="656214310-24052006">23</span></a>.</font></div>
<div> </div>
<div><span class="656214310-24052006"><font face="Arial" size="2">According
to the RFC , it is said that this field is generated by the UA who
started the request. I was just wondering, how did they get the IP
Address at the back ? Which IP Address did they reference it from ?</font></span></div>
</blockquote>
Most often this is the address of the interface the UA is using.<br>
<blockquote
cite="midA0E9DBAAF59F2C49AB566EC7B3907872136A69@EXCH1.superinternet.net.sg"
type="cite">
<div><span class="656214310-24052006"></span> </div>
<div><span class="656214310-24052006"><font face="Arial" size="2">From
the RFC, it also says that the all request/response in the dialog
should use the same Call-ID. When they say this, does it mean the
entire field with the ip address (eg. <a
href="mailto:9ce97fd3-1a800040@172.16.1.123">9ce97fd3-1a800040@172.16.1.123</a>
) or just the front part of it (eg. 9ce97fd3-1a800040 ) ?</font></span></div>
<div><span class="656214310-24052006"></span> <br>
</div>
</blockquote>
Entire.<br>
<br>
<blockquote
cite="midA0E9DBAAF59F2C49AB566EC7B3907872136A69@EXCH1.superinternet.net.sg"
type="cite">
<div><span class="656214310-24052006"><font face="Arial" size="2">I
notice that during a dialog session from a UA to the server going to
the PSTN gateway, it was refering to this Call-ID until the point when
the request was forwarded to the PSTN gateway. When the PSTN gateway
replies, it replied with a same Call-ID with a different IP address at
the back (<a href="mailto:9ce97fd3-1a800040@123.234.123.234">9ce97fd3-1a800040@123.234.123.234</a>
)</font></span></div>
<div><span class="656214310-24052006"></span> </div>
<div><span class="656214310-24052006"><font face="Arial" size="2">172.16.1.123
- Private address of the UA</font></span></div>
<div><span class="656214310-24052006"><font face="Arial" size="2">123.234.123.234
- Public address of the UA</font></span></div>
<div><span class="656214310-24052006"></span> </div>
<div><span class="656214310-24052006"><font face="Arial" size="2">Strange
? Give your comment. Somehow i feel that this implementation is wrong.</font></span></div>
</blockquote>
Yes, a unique dialog is composed of to/from and call-id. Creating a new
call-id creates a new dialog and can only be done by a dialog-creation
SIP message.<br>
g-)
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