Technical Architecture of Exchange Server 2007
In Exchange Server 2007 introduces several architectural changes from previous versions of Exchange. Many features and components have been redesigned, some features have been removed, and several new features have been added.
This document discusses the technical architecture of Exchange 2007, including descriptions of server roles, topologies, and the transport architecture. It is a compilation of several Exchange 2007 Help topics and is provided as a convenience for customers.
Please find the following documentation here