Active Directory generates a default replication topology
among domain controllers in the same domain within a single
site. This default replication topology defines the path for
the Active Directory updates so that all domain controllers
in the same domain receive the updates within that site.

This default replication topology is fault tolerant
between the domain controllers. If there is a break in the
default replication topology between unreachable domain
controllers within a site, replication still continues to
all other domain controllers through the redundant paths.

Active Directory periodically verifies the status of the
current replication topology within a site to ensure that it
is operational. Active Directory reconfigures the
replication topology to reflect any changes in the
environment, such as the addition or permanent removal of a
domain controller.

INTER-Site Replication Overview

Active Directory uses network
connection information to generate default connection
objects (bridgehead servers) to replicate Active Directory
data between sites. These bridgehead servers are the only
connection points between the sites for the purposes of
replication.

You can provide additional information
about the protocol to be used for replication, cost of the
site links (specifically, if there are redundant paths
between sites and certain ones are favored over others),
link availability schedules, etc. to further optimize your
network utilization and to minimize replication traffic by
scheduling what you can during the slow periods of the day
to make replication as efficient as possible and to impact
your network a little as possible.

Well, that wraps up this section
of Learn Active Directory Design and Administration in 15
Minutes a Week - Windows 2000 Global Catalog Server. I hope
you found it informative and will return for the next
installment.

If you have any questions, comments or
even constructive criticism, please feel free to drop me a
note.

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