This article explains how you can control a domain controller contacting a PDC which is out of the site.
This article explains the mechanim Bridgehead Servers use to process the replication changes.
This article explains a small tip or syntax of a command you can use to check the network and DNS settings before deploying a child domain or additional domain controller in an existing forest.
This article explains some notes related to the FRS and SYSVOL replication.
Windows Vista and later have a way of reducing the SYSVOL bloat that happens with Group Policy in earlier versions of Windows.