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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I’m certainly not a network expert (beyond normal network knowledge for an IT person), and I agree with you TCP SHOULD be dropped first because of what you said, but I often heard so-called network expert (or at least some holding jobs as such) say that it`s normal my UDP packets get dropped because they are UDP.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>UDP is, or was until recently, considering to be carrying those “who cares?” packets, like SNMP, etc. Sort of like ICMP. The reverse logic held true, where if it was a mechanism using UDP, it was because nobody really cared about reliability in the first place.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>VoIP may have changed some people`s mind, of course. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Mike<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> asterisk-users-bounces@lists.digium.com [mailto:asterisk-users-bounces@lists.digium.com] <b>On Behalf Of </b>Steve Jones<br><b>Sent:</b> Tuesday, November 30, 2010 1:33 PM<br><b>To:</b> asterisk-users@lists.digium.com<br><b>Subject:</b> Re: [asterisk-users] TCP port, VPN and resolving the cutting voice problem<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Just the contrary - Most QoS schemes will drop TCP first, specifically because it is known that with TCP, the packet will be resent, so no application will be hurt. UDP is not dropped first because it is known that there will likely be more impact.<br><br>I am not aware of any way to run IAX over TCP, and I agree it would be a bad idea. The proper thing to do is to implement PROPER QoS on BOTH SIDES of the link, which I hope is point to point. If it goes over the Internet, your QoS is lost as soon as it hits a router you dont control (or pay for QoS services on)<br><br>I think in IAX, the jitter buffer size can be adjusted, but I dont know the detail on this.. A jitter buffer can be looked upon as like a funnel - as packets arrive, they are dumped in the funnel, which is then pouring your audio out the bottom in a smooth stream, no matter how much delay there is in the filling of the funnel. When the funnel runs out of packets (ie: delay has caused you to run out of data) then you get a break in your audio stream. Increasing the jitter buffer (bigger funnel) can fix this, but at a certain point, the audio will be SO DELAYED (because the packets are waiting in the buffer) that the users will notice and get confused.<br><br><br><br>-Steve<br><br><br><br>---------original message ------<br><br>From: "Mike" <<a href="mailto:list@net-wall.com">list@net-wall.com</a>><br>To: "'Asterisk Users Mailing List - Non-Commercial Discussion'" <<a href="mailto:asterisk-users@lists.digium.com">asterisk-users@lists.digium.com</a>><br>Date: Tue, 30 Nov 2010 12:34:08 -0500<br>Subject: Re: [asterisk-users] TCP port, VPN and resolving the cutting voice problem<br><br>> I know understand the latency due to the resending .. But if the link was<br>have a good speed internet, then resending will make a big latency?<br><br>I think the point is that with TCP, congestion will create a vicious circle<br>of more congestion, while with UDP congestion is bad in itself, but doesn't<br>result in more congestion created by the original congestion.<br><br>That being said, isn't UDP sometimes looked at as being lower priority than<br>TCP by many routers out there and dropped first when congestion does occur?<br>That makes it a good reason to use TCP in some cases.<br><br>Mike<o:p></o:p></p></div></body></html>