What make IP Phones survive.

[msaeedi]

i have an HQ ( main university ) and it has CUCM 9.1 , university has two connection one connection to PSTN and another connection to WAN that connect to small Branch ( collage ) , on that collage there is no PSTN at all, on the branch there is only Router 3921

so i need the configuration of the branch router in such a way that if the WAN link to HQ failed , phones will survive and will register locally on branch router

i need in both cases :

phones are registered using sccp.

phones are registered using sip

another issue , i dont want to register remote Gateway as an MGCP Gateway.

please explain detailed , if anyone do it before , please post the configuration asap

[Chris Deren · Accepted solution]

You would need to configure SRST, you can find plenty of documentation on how to configure it.  However, if there are no PSTN trunks at the remote site what value will it bring? Without PSTN the phones will be able to talk to each other at the remote branch, but nobody else, i.e. outside users nor main campus university.

[msaeedi]

i agree with you of that "but nobody else, i.e. outside users nor main campus university. " , but phones will talk to each other within a branch.

i need to configure SRST with registering a gateway as an MGCP Gateway.

can you help on that

[Jaime Valencia]

As Chris has mentioned, there are already PLENTY of resources on cisco.com and CSC for SRST configuration, have you tried searching and following them?????

You've already asked the exact same thing, and you've already got confirmation that you can it, not sure what you're looking for????

https://supportforums.cisco.com/discussion/12599416/srst-without-mgcp-configuration

[Chris Deren]

SRST has nothing to do with MGCP. What you need to do is define SRST reference in CUCM, assign it to the device pool used by the branch phones, and then configure SRST configuration on the voice GW.  When WAN is lost phones will know to register with the local SRST router, but since there are no local trunks they will not be able to make and/or receive any calls from outside.

If you had a local trunk(s) then those could be used under SRST.