TABLE OF CONTENTS The Site Replication Service (SRS) is in general a poorly understood component of Exchange 2003, and Exchange 2000 before that. For the most part, it's perceived to be a component that allows an Exchange 2003 server to synchronize directory information with an Exchange 5.5 server. In some part, this is true. However, the SRS's role in life is merely to allow an Exchange 2003 server to participate in Exchange 5.5 style directory replication. Why might an Exchange 2003 server need to do this? The remainder of this chapter sets out to explain just that.
Only the Active Directory Connector provides the mechanism to perform directory synchronization between the Exchange 5.5 Directory Service and the AD. The SRS has nothing to do with this exchange of information. The SRS presents itself as an Exchange 5.5 Directory Service to other Exchange 5.5 servers but runs on an Exchange 2003 server. The SRS is only available if you're running Exchange in mixed mode. (A mixed-mode Exchange organization includes Exchange 5.5 Service Pack 3 legacy servers. In Exchange 2000, a mixed-mode organization could also support Exchange 5.0 and Exchange 4.0 servers, but these legacy versions are not supported in terms of interoperability with Exchange 2003.)
Using the SRS to provide a shadow Exchange 5.5 Directory Service allows other Exchange 5.5 servers to continue with Exchange 5.5 directory replication to a particular server in the same way that they always did, even if...
