Global catalog for Connect and Presence
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 about global catalogs, visit the Technet Library to see 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. For instructions on configuring the Connect service to use the global catalog, see Enable BlackBerry collaboration suite users from multiple domains within the same forest.
You can also configure the Presence service to use the global catalog so that the Presence service can subscribe the receive presence information for Lync 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. For instructions on configuring the Presence service to use the global catalog, see Prerequisites: Connect for Microsoft Lync Server and Skype for Business.
To provide this service, in addition to configuring the Connect and Presence services to use the global catalog, you must replicate a couple of additional Lync related attributes to the global catalog. Whether this is for one or both services, this only needs to be done once.