SRST with Local Unity UM

[tmaurello_2]

I need to provide local voicemail/auto attendant during SRST in the event of a WAN outage. The customer has Exchange at both the main site and the remote site which forced us to go with two Unity servers, each co-located with their subscribers message store. During a WAN outage, I lose all voicemail and auto attendant functionality. I could configure the TCL script for the AA part, but lack of voicemail is the big hurdle I am dealing with. I cannot use RDNIS to have voicemail failover to the main site since the subscribers reside on the remote Unity server. Having a separate subscriber at the main site for the entire remote office during the outage is also not an option.

Is there any way to configure some of the ports on the remote Unity server to connect to the SRST gateway - either SIP or SCCP - to handle calls in SRST mode? This would be similar to a Unity to CME connection. Can something like this be done?

I'm running the latest - Unity 4.2, CCM 4.2, SRST 4.0.

Thanks,

- Tony

[JeremyL]

Was looking into the same issue and got back the following from TAC:

- Unity and the router should be co located

- Unity uses some ports as an SCCP integration to the router

- The router should be configured as CME as SRST - as below:

http://www.cisco.com/en/US/products/sw/voicesw/ps4625/products_configuration_guide_chapter09186a00806a7fe8.html

- there are caveats with MWI - if the Unity goes to fallback mode and then goes back to the Call Mgr - then the MWI updates will not work until Unity does its daily update.

So, it looks like it can be done, have not tested it though. The configuration would not be straight forward, such as using CUE during fallback.

[jaber23]

I've read these posts with interest as I need to do the same, I have a remote site (remote from the CallManager) which has a Unity server. How do I configure the Unity to be available to the phones on that site in SRST mode? I've scanned the Unity installguide and see no reference to the SCCP prt integration you talk about.

[tmaurello_2]

After a little research, I figured out how to make this happen. First, you need to upgrade to an IOS that supports CME 4.0. Either 12.4(9)T or 12.4(4)XC. The configuration and integration is very straightforward.

CME 4.0 now has a new feature that allows it to run in an SRST-type configuration. Instead of having the SRST config, you configure CME in SRST-mode. You get all of the benefits of CME with the failover of SRST.

http://www.cisco.com/en/US/partner/products/sw/voicesw/ps4625/products_configuration_guide_chapter09186a00806a7fe8.html

You can also integrate Unity with CME using standard SCCP skinny ports instead of a SIP integration. On the Unity side, all you do is add the CME router as another CallManager in the current integration. On the CME side, you configure ephone-dns and ephones that do the same thing as the voicemail ports in CallManager. It works out great.

http://www.cisco.com/en/US/partner/products/sw/voicesw/ps2237/prod_configuration_guide09186a00806e09b8.html