This guide provides basic instruction on setting up autonomous or replica downstream WSUS servers. Downstream WSUS servers reduce overall off-campus bandwidth as updates are downloaded from Microsoft to the WSUS service once, and then distributed to campus downstream servers.
An autonomous downstream server, like a replica server, also uses another WSUS server as its master repository, but allows for individual approvals for updates different from those of the master. The autonomous server:
Allows flexibility in creating computer groups.
Does not have to be in the same Active Directory forest as the master.