This post is to clarify that a previously discussed feature that was intended for Exchange 2010 SP1 is not present in the SP1 final build.
Update: This feature is now live in the Exchange 2010 SP2 RU3 build of Exchange.
The feature I am referring to is the allow/block cross site RPC Client Access connections. This sometimes comes up in workshops and discussions with clients regarding CAS & DAG interaction. There are numerous blogs (http://tinyurl.com/4yysfp5) and a couple of books that describe the feature.
The original TechNet documentation on the Set-DatabaseAvailabilitygroup cmdlet lists the feature as reserved. This is shown below:
TechNet has since been updated to reflect this change, and the new content is below for reference.
The AllowCrossSiteRpcClientAccess parameter specifies the client access endpoint used by Outlook clients after a cross-site database *over event. The default value is False, which disables cross-site RPC client access. Thus, when a cross-site database *over event occurs, the affected user's Outlook profile will be updated to use the RPC Client Access Server array in the Active Directory site containing the mounted database. If configured with a value of True, the affected user's Outlook profile will not be updated, and the user will continue to connect to the same RPC Client Access Server array. In order to use this parameter, all Mailbox servers in the DAG must be running Exchange Server 2010 Service Pack 2 Rollup Update 3 or later