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<br><br><div class="gmail_quote">On Fri, Dec 11, 2009 at 8:21 AM, Lelio Fulgenzi <span dir="ltr"><<a href="mailto:lelio@uoguelph.ca">lelio@uoguelph.ca</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div><div style="font-family: Verdana; font-size: 10pt; color: rgb(0, 0, 0);">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<div><div></div><div class="h5"><br><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).<br>
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