Hi:I hope to learn about how to partition the emails of one company to be managed by 2 exchange servers. For example, let's say there are 2 departments A and B, and the emails of these two departments' employees are:john@a.company.com (also can receive email from john@company.com)bob@b.company.com (also can receive email from bob@company.com)I am looking for some architectural diagrams that answer a few questions:What types of servers do we need? (2 or 3 exchange servers? 2 or 3 active directory servers?)What is the sequence of actions that reserve names during creation of accounts? For example, john@a.company.com will also reserve the email address john@company.com.What is the sequence of interaction during mail routing?What is the sequence of interaction during calendar appointment? How will bob know where to get john's free/busy information?I tried to get this information online but couldn't find a good web page that describes these topics. If you know about the answers, or can point me to a page or a book, that will be great.Thanks in advance!Ken

I'm not sure about diagrams, but I believe your design request is fairly simple to implement. Asingle active directy server (2003)would suffice. More AD servers don't directly add more Exchange functionality. Redundancy, site topology and workload are more direct reasons for multiple AD servers A single Exchange 2k7 server would be enough for the design, however if you have other business requirements dictating theneed to flow domain "A.company.com" through one server and "B.company.com" through another, then get two exchange servers, with hub transport roles installed on each. (Again, I'm stating the minimum.) The configuration is done at the send and receive connector level. The use of Edge transport servers would increase the server requirement as well. They cannot share a box with any other role. "Free/Busy" is now handled by the Availability Service, as described here: http://msexchangeteam.com/archive/2006/10/23/429296.aspx I'm not sure I understand the mail routing question, but all mail would go through hub transport servers, which are determined automaticly. Questions for you: How many AD domains do you have? How many sites do you have? How many users / mailboxes / total storage size do you have redundancy / fault tollorance requirements? What is the reason for this separation? Is it just the flow of mail, or storage as well?