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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>I’m almost completely positive Lelio is correct in the way
this works. I remember doing this in the lab, but it’s been a while<o:p></o:p></span></p>
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<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"'>
cisco-voip-bounces@puck.nether.net [mailto:cisco-voip-bounces@puck.nether.net] <b>On
Behalf Of </b>Karen Cheng<br>
<b>Sent:</b> Thursday, December 10, 2009 4:32 PM<br>
<b>To:</b> Lelio Fulgenzi<br>
<b>Cc:</b> cisco-voip@puck.nether.net; anand<br>
<b>Subject:</b> Re: [cisco-voip] WAN failure in call manager<o:p></o:p></span></p>
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<p class=MsoNormal style='margin-bottom:12.0pt'>Hi Lelio,<br>
<br>
I don't believe that part about the phone triggering the SRST function is true.
>From memory I believe the SRST router is the one that detects the WAN failure
in which after a certain amount of time (dependent on how many servers in the
CM cluster) it reconfigures itself to be the call agent instead. It then also
continues to monitor connectivity to the CM cluster and once backup will again
wait (dependent on how it is configured, wait until no calls are active etc)
before handing the call agent functions back to the CM cluster.<br>
<br>
I may be wrong though.<br>
<br>
Karen<o:p></o:p></p>
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<p class=MsoNormal>On Fri, Dec 11, 2009 at 8:21 AM, Lelio Fulgenzi <<a
href="mailto:lelio@uoguelph.ca">lelio@uoguelph.ca</a>> wrote:<o:p></o:p></p>
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<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";
color:black'>Correct, during the SRST mode, the CUCM cluster is not controlling
anything. The phones register to the SRST router using a "simplified"
configuration they store in memory. The tell the router what DNs it is supposed
to have, and the router configures the appropriate dial-peers. Then using the
dynamic dial peers it can call other phones, or using the static dial-peers
(ones you program) a phone can call off-net using PSTN.<br>
<br>
Interesting thing is this, SRST is "always on" waiting for a device
to register to it. The device is what controls when it talks to the SRST router
or not. That's how you can test registering devices to the router when the WAN
really isn't down.<br>
<br>
It also means that if there is some way or scenario that your phones may not be
able to talk to CUCM, but your router can, you will have phones that can call
each other, but not out the PSTN because the gateways are still registered to
CUCM. That is, of course, if you have MGCP gateways. If you have H323 gateways,
I think it's a moot point.<br>
<br>
Of course, I could be wrong on one or two points, and would be happy to learn
something new. ;)<br>
<br>
<br>
<br>
---<br>
Lelio Fulgenzi, B.A.<br>
Senior Analyst (CCS) * University of Guelph * Guelph, Ontario N1G 2W1<br>
(519) 824-4120 x56354 (519) 767-1060 FAX (JNHN)<br>
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^<br>
"Bad grammar makes me [sic]" - Tshirt<o:p></o:p></span></p>
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<br>
<br>
----- Original Message -----<br>
From: "anand" <<a href="mailto:anand.eee@gmail.com" target="_blank">anand.eee@gmail.com</a>><br>
To: <a href="mailto:cisco-voip@puck.nether.net" target="_blank">cisco-voip@puck.nether.net</a><br>
Sent: Thursday, December 10, 2009 5:15:00 PM GMT -05:00 US/Canada Eastern<br>
Subject: Re: [cisco-voip] WAN failure in call manager<br>
<br>
Hi,<br>
<br>
I have been breaking my head to understand the exact functions of SRST. During
the WAN failure, SRST router takes PSTN path.My question is during this time
will the call manager controls the call or Call Manager is completely out of
operation(I mean it does not take any part in the call control on the PSTN
path).<o:p></o:p></span></p>
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<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";
color:black'>_______________________________________________ cisco-voip mailing
list <a href="mailto:cisco-voip@puck.nether.net" target="_blank">cisco-voip@puck.nether.net</a>
<a href="https://puck.nether.net/mailman/listinfo/cisco-voip" target="_blank">https://puck.nether.net/mailman/listinfo/cisco-voip</a>
<o:p></o:p></span></p>
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