Got it. Thanks. Makes sense to keep an extra two in mind for conference etc....<div><br></div><div>Off topic - what is top post? I am using gmail + chrome - no ugly Outlook.<br><br><div class="gmail_quote">On Fri, Jan 14, 2011 at 3:33 PM, Danny Nicholas <span dir="ltr"><<a href="mailto:danny@debsinc.com">danny@debsinc.com</a>></span> wrote:<br>
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<p class="MsoNormal"><font size="2" color="navy" face="Arial"><span style="font-size:10.0pt;font-family:Arial;color:navy">Hurray for Microsoft Outlook (for creating
this whole top-post thread). Just my .02; The other two ports must have been
a remnant of another channel; as for the 4 ports – I think that the 4
port requirement is probably for “niceties” like conferencing and
transfers.</span></font></p>
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<p class="MsoNormal"><b><font size="2" face="Tahoma"><span style="font-size:10.0pt;font-family:Tahoma;font-weight:bold">From:</span></font></b><font size="2" face="Tahoma"><span style="font-size:10.0pt;font-family:Tahoma">
<a href="mailto:asterisk-users-bounces@lists.digium.com" target="_blank">asterisk-users-bounces@lists.digium.com</a>
[mailto:<a href="mailto:asterisk-users-bounces@lists.digium.com" target="_blank">asterisk-users-bounces@lists.digium.com</a>] <b><span style="font-weight:bold">On Behalf Of </span></b>Bruce B<br>
<b><span style="font-weight:bold">Sent:</span></b> Friday, January 14, 2011
2:15 PM</span></font></p><div class="im"><font size="2" face="Tahoma"><br>
<b><span style="font-weight:bold">To:</span></b> Asterisk
Users Mailing List - Non-Commercial Discussion<br>
<b><span style="font-weight:bold">Subject:</span></b> Re: [asterisk-users] Why
are 4 ports used for a single call?</font></div><p></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">Thanks guys. I am not sure whether that call
was asymmetric or not but I saw 4 ports open. It could be that the
other two ports were </span></font><span><font face="Arial"><span style="font-family:Arial">remnant </span></font></span>of
another channel even though I doubt it. </p><div><div></div><div class="h5">
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">Now, when I tried again, it is only 2 ports that is opened like you
mentioned, even RTP port, and RTP port +1. So, does Asterisk usually use
the symmetric method or is the asymmetric method used as
well by some media servers? </span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">The reason why I am asking is because there are many many
online responses that there is 4 ports needed per call and make sure
you keep enough ports open, blah blah...</span></font></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">Thanks again</span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">On Fri, Jan 14, 2011 at 2:57 PM, Gary Allen <<a href="mailto:solstars1@gmail.com" target="_blank">solstars1@gmail.com</a>> wrote:</span></font></p>
<p class="MsoNormal" style="margin-bottom:12.0pt"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">RTP always uses a random
even numbered port, then RTCP will use the next port, which will always be odd
numbered. Symmetric RTP only needs two ports, while asymmetric RTP uses
four.<br>
<br>
<a href="http://www.armware.dk/RFC/rfc/rfc4961.html" target="_blank">http://www.armware.dk/RFC/rfc/rfc4961.html</a><br>
<br>
<br>
</span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">On Fri, Jan 14, 2011 at 12:44 PM, Bruce B <<a href="mailto:bruceb444@gmail.com" target="_blank">bruceb444@gmail.com</a>>
wrote:</span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">I mean part of RTP RFC?</span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">On Fri, Jan 14, 2011 at 2:41 PM, Bruce B <<a href="mailto:bruceb444@gmail.com" target="_blank">bruceb444@gmail.com</a>>
wrote:</span></font></p>
<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">Hi Everyone,</span></font></p>
<div>
<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt"> </span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">I am just tweaking a pfSense router and learning lots about NAT
etc....I noticed that each call uses four UDP port for RTP. Here is an example
of port for a call I made:</span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt"> </span></font></p>
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<div>
<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">10200</span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">10201</span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">10504</span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">10505</span></font></p>
</div>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">Seems like they are random in pair. I have a restriction of 10000-11000
in my rtp.conf so that makes sense. But why use 4 ports per call? is that part
of SIP RFC?</span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt"> </span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">Thanks</span></font></p>
</div>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">--<br>
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