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<DIV style="FONT: 10pt arial">
<DIV><FONT size=2 face=Arial>Customer is complaining about noise, drops,
breakup, etc. I have taken several packet captures from the switch. When I
listen them them with the Wireshark defauilt jitter buffer of 50 ms, I hear the
problems the customer is reporting. If I set the wireshark jitter buffer to
160ms, which is the same jitterbuffering we do to packets going out to the PSTN,
the problems disappear. Almost all of the issues identified by wireshark at 50ms
jitterbuffer are packets dropped for exceeding the jitter buffer.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Changing this on almost any device is simple and
straightforward, except for these NEC DT700 phones.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV></DIV></DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px"
dir=ltr>
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=Dennis.Heim@cdw.com href="mailto:Dennis.Heim@cdw.com">Dennis Heim</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=mays@win.net
href="mailto:mays@win.net">Joseph Mays</A> ; <A
title=cisco-voip@puck.nether.net
href="mailto:cisco-voip@puck.nether.net">cisco-voip@puck.nether.net</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, February 20, 2012 2:24
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> RE: [cisco-voip] Jitter
buffering on NEC phones</DIV>
<DIV><BR></DIV>
<DIV class=WordSection1>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">I
guess the first thing I would be curious as to what is the reason for
adjusting the jitter buffer. What issues are you
encountering?<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><o:p> </o:p></SPAN></P>
<DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #1f497d; FONT-SIZE: 10pt">Dennis
Heim<BR>Senior Engineer (Unified Communications)<BR>CDW Advanced
Technology Services<BR>10610 9<SUP>th</SUP> Place<BR>Bellevue, WA
98004<BR><BR>425.310.5299 Single Number Reach (WA)<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #1f497d; FONT-SIZE: 10pt">317.569.4255
Single Number Reach (IN)<BR>317.569.4201 Fax</SPAN><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">
<BR><A href="mailto:dennis.heim@cdw.com"><SPAN
style="COLOR: blue; FONT-SIZE: 10pt">dennis.heim@cdw.com</SPAN></A></SPAN><U><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: blue; FONT-SIZE: 11pt"><BR></SPAN></U><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><A
href="http://www.cdw.com/content/solutions/unified-communications/"><SPAN
style="COLOR: blue">cdw.com/content/solutions/unified-communications/</SPAN></A><o:p></o:p></SPAN></P></DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><o:p> </o:p></SPAN></P>
<DIV>
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<P class=MsoNormal><B><SPAN
style="FONT-FAMILY: 'Tahoma','sans-serif'; FONT-SIZE: 10pt">From:</SPAN></B><SPAN
style="FONT-FAMILY: 'Tahoma','sans-serif'; FONT-SIZE: 10pt">
cisco-voip-bounces@puck.nether.net [mailto:cisco-voip-bounces@puck.nether.net]
<B>On Behalf Of </B>Joseph Mays<BR><B>Sent:</B> Monday, February 20, 2012
10:44 AM<BR><B>To:</B> cisco-voip@puck.nether.net<BR><B>Subject:</B>
[cisco-voip] Jitter buffering on NEC phones<o:p></o:p></SPAN></P></DIV></DIV>
<P class=MsoNormal><o:p> </o:p></P>
<DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt">My apologies in
advance for sending this to the Cisco VOIP list, since it's not, strictly
speaking, a cisco issue, but I'm hoping to find someone here who has worked
with NEC DT700 voip phones, because we are trying to get an answer to what
should be a simple question, but no amount of calling to NEC has yielded an
answer, and multiple searches online have proven
useless.</SPAN><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal> <o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt">We are trying to
figure out how to set the jitter buffer in NEC DT700 phones to 160ms. Or set
the buffer for 16 10ms packets. We have a template config we found on NEC's
site that contains all the parameters that can be set for the phone, but no
amount of begging NEC support through several layers of escalation has yielded
a simple answer to what exactly are the config parameters we want. The section
they are in is easy enough to identify; it should be one or two of the
following parameters --</SPAN><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal> <o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt">phone.audio.rfc2833.dtmf.relay="0"
phone.audio.onhook.dtmf.mode="1" phone.audio.pcmu.pref="4"
phone.audio.pcma.pref="5" phone.audio.g722.pref="3" phone.audio.g729.pref="6"
phone.audio.g7221.24kbps.pref="1" phone.audio.g7221.32kbps.pref="2"
phone.audio.g729.vad="1" phone.audio.pcmu.ptime="80"
phone.audio.pcma.ptime="80" phone.audio.g722.ptime="80"
phone.audio.g729.ptime="80" phone.audio.g7221.24kbps.ptime="80"
phone.audio.g7221.32kbps.ptime="80" </SPAN><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal> <o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt">The codec we are
using is G711, so it's probably among the default values, rather than the
values aimed specifically at g722 or others.</SPAN><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal> <o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt">Again, my apologies
for sending it here, I have been very hesitant to do so for days, but we are
out of other options, and at this point are just hoping that there is either
someone who knows DT700 phones or knows VoIP in general enough that they can
identify what we need to set for 160 ms (16 10ms packets) jitter
buffer.</SPAN><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal> <o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt">Joe
Mays</SPAN><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal> <o:p></o:p></P></DIV></DIV></BLOCKQUOTE></BODY></HTML>