A global catalog server is available to directory clients when Domain Name System (DNS) servers can locate it
as a global catalog server. In which order do the following events need to occur before the catalog server is
ready?
A) The Net Logon service on the domain controller has updated DNS with global-catalogspecific service (SRV)
resource records.
B) The isGlobalCatalogReadyrootDSE attribute is set to TRUE.
C) The global catalog receives replication of read-only replicas to the required occupancy level.

A.
C then A, then B

B.
B then C, then A

C.
A then C, then B

D.
C then B, then A

Explanation:
http://technet.microsoft.com/fr-fr/library/cc739901%28v=ws.10%29.aspx
Verify global catalog readiness When a global catalog server has satisfied replication requirements, the
isGlobalCatalogReady Root DSE attribute is set to TRUE and the global catalog is ready to serve clients.
http://technet.microsoft.com/de-de/library/howglobal-catalog-serverswork%28v=ws.10%29.aspx
How the Global Catalog Works Global Catalog Server Creation and Advertisement By default, before a domain
controller advertises itself as a global catalog server in DNS, the global catalog contents must be replicated to
the server. This process involves replication of a partial, read-only replica of every domain in the forest except
for the domain for which the new global catalog server is authoritative. The duration of this process depends on
how many domains the forest contains, the size of the domains, and the relative locations of source and
destination domain controllers. If multiple domains are in the forest and if source domain controllers are located
only in distant sites, the process takes longer than if all domains are in the same site or in only a few sites.
When replication must occur between sites to create the global catalog, replication occurs according to the site
link schedule. Requirements for Global Catalog Readiness By default, a global catalog server is not considered
“ready” (the server advertises itself in DNS as a global catalog server) until all read-only directory partitions
have been fully replicated to the new global catalog server. The Global Catalog Partition Occupancy registry
entry under HKEY_Local_Machine\\System \\CurrentControlSet \\Services\\NTDS\\Parameters determines the requirements for how many read- only directory partitions must be present
on a domain controller for it to be considered a global catalog server, from no partitions (0) to all partitions (6).
For domain controllers that run Windows Server 2003 or later, the default occupancy value requires that all
read-only directory partitions be replicated to the global catalog server before the Net Logon service registers
SRV resource records in DNS. For most conditions, this default provides the best option for ensuring that a
global catalog server provides a consistent view of the directory. In less common circumstances, however, it
might be useful to make the global catalog server available with an incomplete set of partial domain directory
partitions for example, when delay of replication of a domain that is not required by users is jeopardizing their
ability to log on.