Before you perform the forest preparation step to prepare Active Directory Domain Services (AD DS) for Office Communications Server 2007 R2, you must decide where to store global settings by evaluating several factors.
Evaluating Global Settings Locations
When you perform forest preparation, you need to select a location to store Office Communications Server global settings. You can select either the System container in the root domain or the Configuration container, which is replicated forest-wide.
Several factors, as illustrated in the following decision tree, can help you determine the best location for your organization.
Decision tree for global settings location
Live Communications Server 2005
Do you have Microsoft Office Live Communications Server 2005 with Service Pack 1 (SP1) installed? If so, the Configuration container is not an option. Choose the System container.
If you implemented Live Communications Server 2005 in a centralized topology and are moving toward a distributed topology, you may experience performance problems with servers or Microsoft Management Console (MMC) that are related to root domain access. In this case, you can migrate your global settings from the System container to the Configuration container. For details about migrating global settings to the Configuration container, see Migrating Global Settings Container.
Mature Exchange implementation
Do you have a mature Exchange implementation for which you have been able to assess the impact of replication traffic on your network? If so, Exchange configuration settings are already replicating forest-wide, so adding Office Communications Server global settings to the Configuration container should not significantly impact your network. Choose the Configuration container.
Do you have a distributed forest that has Active Directory domains or sites without fast, reliable connections to a domain controller in the root domain? If so and you plan to deploy servers running Office Communications Server (except Edge servers, which are not joined to the domain) in these locations, choose the Configuration container.
Empty root domain
Does your forest have a root domain that does not host users or servers? If so, are there any child domains without a fast, reliable connection to a domain controller in the root domain? If so and you plan to deploy servers running Office Communications Server (except Edge servers, which are not joined to the domain) in such a domain, choose the Configuration container. This situation is similar to the distributed forest situation described above.
Are you performing a new, straightforward installation, in an environment without Live Communications Server, Exchange, or a complex forest? If so, choose the System container to reduce Active Directory replication traffic on your network.