The global catalog is a distributed data repository that contains a searchable, partial representation of every object in every domain in a multi-domain Active Directory Domain Services (AD DS) forest. Global catalogs are typically used in a single AD DS forest that has more than one domain. A global catalog provides a way for products and services to access data that is available in other domains in the same forest. For more information, see the Microsoft resource What Is the Global Catalog?.

You can configure the Connect service to use the global catalog so that the Connect service can find users who exist in other domains within your AD DS forest. This enables the BlackBerry Connect app to search for people in those other domains and start conversations with them, or add them to the contact list.

You can also configure the Presence service to use the global catalog so that the Presence service can subscribe the receive presence information for Skype for Business users who exist in other domains within your AD DS forest. This is helpful if you are using a Presence client, such as BlackBerry Work, by users who email with others who reside in other domains in your AD DS forest.

In addition to configuring the Connect and Presence services to use the global catalog, you must replicate some additional Skype for Business attributes to the global catalog. You must perform this set up only once, whether the global catalog is used for one or both services. Some environments might require some Active Directory attributes to be correctly replicated to the global catalog in the other domains.