Here are the requirements for bandwidth between Exchange and Unity:
http://www.cisco.com/univercd/cc/td/doc/product/voice/c_unity/sysreq/40_sysrq.htm#96744
While I can't find any documentation that says so, I seriously doubt Unity is supported at remote sites without some sort of call processing engine also at that remote site (be it another callmanager or callmanager express). Even if it's just voice mail only for the users at that remote site, you've got to think about the skinny traffic that's going to flow between the two servers. Keepalives are sent every 15 seconds, and if we miss just a couple of those (due to congestion over a slow link), the ports will unregister and attempt to reregister. Not a good thing if this is during production hours.
adam
