Call Manager at small remote sites?

[apbaseball]

Hello there,

We are looking for the best/easiest solution to implement at our small remote sites to tie them into our call manager solution at our HQ. Our current system is 1 Call Manager Pub and 1 Sub as well as 1 Unity Connection Pub and 1 Sub virtualized at our HQ. We have about 150 SCCP phones on site at our HQ utilizing these services. 

What is our best move to tie in our small remote offices (largest is 30 users, others are 5-10)? Our largest remote office has Exchange servers on site.

Should we just purchase a handful of integrated service routers - ie. 2901, 2911, 2921's and leverage SRST? Should we leverage the Exchange installs for Unified Messaging? There are so many options, I'm just not sure where to go from here.

Any insight would be much appreciated!

[Chris Deren]

Have you had the opportunity to review CUCM SRND? It covers best practice deployment models for models such as yours. Centralized model with SRST at the branch is the recommended solution for such a deployment with either local trunking at the branch or centralized i.e. SIP trunking at the head end site(s).  If there is separate Exchange environment at the site (not sure why you would have that) and these Exchange mailbox servers are separate from centralized Exchange environment you can definitely integrate multiple Exchange servers with centralized Unity Connection for unified messaging. However if the Exchange servers are simply part of the wide Exchange cluster then you should not need a separate integration as mailboxes should be found on any server if integration is built properly.