[cisco-voip] WAN failure in call manager

[Wes Sisk]

it depends.

For MGCP functionality the gateway is monitoring CM.  When failure is 
detected router follows the configured fallback apllication, usually h.323
http://www.cisco.com/en/US/docs/voice_ip_comm/cusrst/admin/srst/configuration/guide/srs_wlan.html#wp1351962

That is only for the gateway though.

Phones monitor CM connecvity. When phone loses connectivity to CM they 
attempt to register with SRST router.  When they register they tell the 
router about their configuration.

To that end it is both phone initiated and gateway initiated.  The 
gateway does not control all logic, nor does the phone control all logic.

/Wes

On Thursday, December 10, 2009 5:32:16 PM, Karen Cheng 
<kaz.cheng at gmail.com> wrote:
> Hi Lelio,
>
> 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.
>
> I may be wrong though.
>
> Karen
>
> On Fri, Dec 11, 2009 at 8:21 AM, Lelio Fulgenzi <lelio at uoguelph.ca 
> <mailto:lelio at uoguelph.ca>> wrote:
>
>     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.
>
>     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.
>
>     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.
>
>     Of course, I could be wrong on one or two points, and would be
>     happy to learn something new. ;)
>
>
>
>     ---
>     Lelio Fulgenzi, B.A.
>     Senior Analyst (CCS) * University of Guelph * Guelph, Ontario N1G 2W1
>     (519) 824-4120 x56354 (519) 767-1060 FAX (JNHN)
>     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>     "Bad grammar makes me [sic]" - Tshirt
>
>
>
>     ----- Original Message -----
>     From: "anand" <anand.eee at gmail.com <mailto:anand.eee at gmail.com>>
>     To: cisco-voip at puck.nether.net <mailto:cisco-voip at puck.nether.net>
>     Sent: Thursday, December 10, 2009 5:15:00 PM GMT -05:00 US/Canada
>     Eastern
>     Subject: Re: [cisco-voip] WAN failure in call manager
>
>     Hi,
>
>     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).
>
>     _______________________________________________ cisco-voip mailing
>     list cisco-voip at puck.nether.net
>     <mailto:cisco-voip at puck.nether.net>
>     https://puck.nether.net/mailman/listinfo/cisco-voip
>
>     _______________________________________________
>     cisco-voip mailing list
>     cisco-voip at puck.nether.net <mailto:cisco-voip at puck.nether.net>
>     https://puck.nether.net/mailman/listinfo/cisco-voip
>
>
> ------------------------------------------------------------------------
>
> _______________________________________________
> cisco-voip mailing list
> cisco-voip at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-voip
>   

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://puck.nether.net/pipermail/cisco-voip/attachments/20091210/1c7a6c32/attachment.html>