UC520 as a voice gateway for 2951 CME-SRST

[mohamed Yatim]

I am currently using a  Cisco 2951 router for CME-SRST in my branch office in the event that our MPLS link failed and the CUCM inside our datacenter is unreachable from the branch office.

The problem now is that my IP Phones are all able to register to my 2951 router when the CUCM is unreachable but they are only able to do extension calling between themselves, they can't receive incoming calls or outgoing calls from PSTN as there is no voice gateway in our branch office.

We have an old Cisco UC520 with 8 x FXO ports lying around and I am thinking of configuring it as the voice gateway in my branch office. I know that UC520 doesn't support SRST at all and so is it possible for me to route incoming and outgoing calls to PSTN for my branch office in the event of a CUCM unreachable event ?

Can someone please help to advise how should I configure my Cisco 2951 and UC520 for this purpose ?

[Ayodeji Okanlawon]

Mohamed,

Yes this is very much possible. Just configure voip dial-peers between your UC520 and 2951 branch router.

What you need to do..

1. Get your fxo line up, ie cetup your fxo on uc520 to your service provider

2. configure your fxo ports

3. configure voip dial-peers directing all inbound pstn calls from uc520 to the 2951

4. configure all outbound pstn calls in SRST to the uc520

This should get thins going pretty easily

[mohamed Yatim]

Ayodeji,

How do I configure dial-peers in my 2951 for use only in SRST mode ?

I want the dial-peers configured inside my 2951 to stop taking effect once my CUCM is reachable again ? is this even possible at all ?