SRST and Call manager

Answered Question
Jun 13th, 2009


i have in the same LAN cluster of 2 server call manager 6.1 ( publisher and suscriber).the publisher works as secondary subsriber.

I have one H323 gateway (router 2811) in tha same LAN.

the customer wants to configure this router as SRST, when phone lost connections with cluster, they subsribe with this router(H323 gateway)that is in the same network LAN.

Is this possible ?

thanks foe advice.

Correct Answer by Chris Deren about 7 years 8 months ago


No need to copy any files.


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Overall Rating: 5 (1 ratings)
Chris Deren Sat, 06/13/2009 - 07:24

Sure it is, but what's the point? The likelihood of both servers being down is very low, typically it is not a practice to configure the GW for SRST at the head end site, since you have the servers there. Also, keep in mind that SRST is not a free thing and the customer needs to purchase SRST licenses in order to be able to legally use it.



bsaid1977 Sat, 06/13/2009 - 07:46

thanks for your replay.

the customer have CISCO2811-CCME/K9, so the cme can work as SRST.

if you can confirm that if i configure this gateway as srst in the publisher and

in the router i make this config:


srst mode auto-provision all

srst dn line-mode dual

srst dn template 3

srst ephone description srst fallback auto-provision phone.

i don't understand this situation, the call manager send a file configuration to the router, and the phones see the router and the cluster in tha same time,

there is no confilct.


Chris Deren Sat, 06/13/2009 - 07:51

Ok, yes you can use CME as SRST.

The way it works is by defining SRST reference in CallManager by specifying the IP address of the SRST GW, then assign this SRST reference to the device pool of the phones. Once phone loose connection to CM servers they attempt to register with the SRST router. You also need the following commands under telephony-service

max-ephones X

max-dn Y

ip source-address x.x.x.x port 2000



bsaid1977 Sat, 06/13/2009 - 07:58

ip source-address x.x.x.x port 2000 ,

the X.X.X.X is the address ip of the router ?

shoud I copy the all file ( firmware,music on hold, ring file, and local file(language)? in the flash.

thank you


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