Directory Synchronization
Directory Synchronization allows organizations with an Active Directory (AD) environment to synchronize the AD users and groups to an Office 365 subscription. The Directory Synchronization tool provided by Microsoft can only synchronize a single AD forest and within this single forest, all the domains are synchronized.
Microsoft offers two versions of the Directory Synchronization software. The 32-bit version , which was the first version released, followed by the 64-bit version. Currently these two versions are in feature parity. The 32-bit version is based on Microsoft's Identity Lifecycle Manager 2007 (ILM) and the 64-bit version is based on Microsoft's Forefront Identity Manager 2010 (FIM).
Once you deploy Directory Synchronization in your environment, you should consider this server to be a permanent addition to your environment. Microsoft will likely phase out the 32-bit version of the Directory Synchronization software, so it's highly recommended that you...