<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv=Content-Type content="text/html; charset=us-ascii">
<meta name=Generator content="Microsoft Word 12 (filtered medium)">
<style>
<!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;}
@page Section1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.Section1
{page:Section1;}
-->
</style>
<!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang=EN-GB link=blue vlink=purple>
<div class=Section1>
<p class=MsoNormal>We have a customer running CUMC V4 with a remote site across
a private leased line. At the remote site we have IP phones and two H323
voice gateways. Users at the remote site can make internal local calls and
calls across the WAN. They can make and receive calls through both the H323
gateways in the remote site.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>The customer now has a 20Mb Metro-Ethernet MPLS circuit
between the two sites and has re-routed the traffic between the two sites from
the private leased line to the MPLS circuit.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Following this change, the users at the remote site can
still make internal local calls and calls across the WAN. They can make
outgoing calls through either of the two H323 voice gateways at the remote
site.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>The problem is with incoming calls through either of the voice
gateways at the remote site. When either of the two remote H323 gateways
receives an incoming call, it rings the extension but when the user takes the
phone off-hook, the calling party still hears ringing and the called party
hears nothing. If the called party places the phone back on-hook, it starts
ringing again. If the calling party continues to wait, the call goes to
voicemail.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Debugging the H225/245 on the gateway, we see the H225
signalling traffic to the CUCM when the call comes in but when the phone is
taken off-hook to answer the call, there is no H225/245 traffic back from the
CUCM to complete the e call.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>If we re-route traffic back across the leased line, it all
works fine.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>All routing has been thoroughly checked and none of the H323
source bind addresses have been changed. Our next step is to take sniffer
traces from each end of the link to analyse the H323.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>The only time I have seen something similar was when a
firewall in the MPLS cloud decided the H225 traffic was a DOS attack and closed
the session but we are assured there are no firewalls in the network.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Has anyone seen anything similar or have any ideas what may
be causing the problem.<o:p></o:p></p>
</div>
<br><br>
<P align=center>This message has been scanned by <A href="http://www.mailcontroller.altohiway.com/">MailController</A>.</P>
</body>
</html>